RCU Review: Top Flite B-25J Mitchell ARF


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    Contributed by: Ken Isaac | Published: June 2008 | Views: 107873 | email icon Email this Article | PDFpdf icon
    Top Flite B-25J Mitchell - RCU Review

    Review by: Ken Isaac (RCKen) | Email me


    Distributed Exclusively by: Great Planes
    Model Manufacturing Company


    P.O. Box 9021
    Champaign, IL 61826-9021
    www.greatplanes.com



     
    • High quality hardware
    • Well engineered
    • Complete & thorough instruction manual
    • Easy assembly
    • Scale interior parts included
    • Outstanding flying plane
    • Very high "fun" factor
    • Plane lends itself to modifications to add further scale features.

     
    • No parts identification page
    • Foam Wheels
    • CA on Nose Canopy
    • Small screws made of softer metal
    • Color on scale interior parts

     

     

     

     

     

     

     

     


    I have noticed that there are two types of planes that seem to get everybody at a flying field to stop what they are doing and watch the plane flying; a classic warbird and a twin engine plane. And you can bet that a twin engine warbird is going to really get some attention. So when I found out that Top Flite was coming out with a B-25 I was really hoping that I would get a chance to review this plane.

    The workhorse of World War II

    Originally designed for the Army Air Corps, the B-25 was known world-wide as the most devastatingly effective medium-range bomber of its time. By the end of the war, nearly 10,000 B-25s had been manufactured for use as bombers, naval anti-submarine patrols, Air Force reconnaissance platforms, air-to-ground attack/strafing asset and VIP transport. To date, it is the only United States military aircraft ever named for an individual.

    Top Flite has a long history of producing some of the best kits that have been made. Their quality and attention to details have always rewarded the builder with a top-of-the-line model when they were finished building. So it's perfectly reasonable to expect their ARF's would have the same high quality as their kits.

    So, let's open up the box and see what this plane has to offer.....

     



    Top Flite B-25J Mitchell ARF
     

    Specifications
    Price: $649.88
    Wingspan: 88.5 in (2255 mm)
    Wing Area: 1036 in sq. (66.8 dm sq.)
    Weight: 17-19 lb (7.7-8.6 kg)
    Wing Loading: 38-42 oz/in sq. (116-128 g/dm sq.)
    Length: 70.5 in (1795 mm)
    Requires: 8-channel radio w/13 servos & two 2-stroke .46-.50 cu in (7.5-8 cc) or
    two 4-stroke .70 cu in (11.5 cc) glow engines.

    Key Features

    • Construction: Balsa and plywood

    • Wings: Plug-in type for easy, accurate assembly with removable outboard and inboard wing panels

    • Covering: Pre-covered in flat Top Flite MonoKote, color scheme is flat gray and flat olive drab with black and white trim.

    • Radio Compartment: Plywood reinforced

    • Cowling: Fiberglass

    • Engine Nacelles: Constructed of fiberglass over built-up wooden understructure

    • Canopy and Windows: Clear molded plastic

    • Landing Gear: Fixed wire .197" (5mm) diameter with scale fiberglass landing gear doors. Includes instructions and hardware for operational spring loaded mechanism to open and close the doors when using the optional Robart Retracts (ROBQ1624)

    • Wheels: Foam construction, two 3.8" (98mm) diameter main wheels and one 2-5/8" (68mm) nose wheel

    • Aileron Control: Dual servos

    • Interior Features: Detailed nose gunner deck including, ammo boxes, kneeling pad and pivoting .50 caliber machine gun; Twin .50 caliber tail machine guns, .50 caliber side mounted machine guns; Detailed instrument panel

    • Fuel Tanks: Two 14.2oz (420cc)

    • Building Time: Ready to fly in approximately 45 hours

    • Warranty: Top Flite Models guarantees this kit free of defects in material and workmanship at the date of purchase. This warranty does not cover any component parts damaged by use or modification.

    Required to Complete

    • Engines: Two .46-.50 cu in (7.5 - 8cc) 2-stroke OR Two .70 cu in (11.5cc) 4-stroke

    • Exhaust: Standard mufflers supplied with engines

    • Radio: 7-channel without landing gear 8-channel with landing gear

    • Servos: Ailerons: 2 standard Elevator: 1 high torque at least 50oz (FUTM0075) Throttle: 2 standard for independent throttle control Rudder: 2 mini at least 35oz torque (FUTM0415) Flaps: 4 standard (2 for inboard panels, 2 for outboard) Nose Steering: 1 standard Landing Gear: 1 standard

    • Servo Extensions: Four 6" (152mm) Two 12" (300mm) Five 24" (600mm) One 36" (910mm)

    • Y-Harnesses: Five

    • Receiver Battery: 2000mAh minimum

    • Misc. Items: Glow plugs, 1/2" foam rubber padding, medium fuel tubing fuel filter, propeller based on engine selection

    Actual Flying Weight: 19 lbs, 8 oz.
    Engine Used: OS FL-70 4-stroke, 2 each.
    Radio Used: Futaba T9CAP Super, Futaba R149DP PCM 72 MHz receiver
    Channels Used: 9 total. Throttle - 2 channels, Flaps -1 channels, Rudder - 2 channels (1 Rudder & 1 Nose Wheel Steering), Ailerons - 1 channel w/Y-harness, Elevator - 1 channel, Retracts - 1 channel
    Servos Used: 8 each, Futaba S3004 Servo Standard Ball Bearing (2 aileron, 4 flaps, 1 nose wheel steering). 1 each,
     Futaba S9001 Servo Aircraft Coreless Ball Bearing (Elevator). 2 each,  Futaba S3115 Micro Precision Servo (2 Rudders)
    Props Used: APC 13x6 Sport Propellers (used for maiden flights), Master Airscrew 12x8 3-Bladed G/F Nylon Propeller

    Required Tools and Adhesives

    In addition to common hobby tools and household tools, this is the "short list" of the most important items required to build the B-25 ARF. Great Planes Pro? CA and Epoxy glue are recommended.

    Foremost, a Great Planes Standard 3/32" Ball Wrench (GPMR8002) and a Great Planes Standard .050" Ball Wrench (GPMR8000) are virtual necessities for assembling this model. These are long-handle Allen wrenches that will be invaluable for mounting the cowls and the other  scale details.

    • 1 oz. [30g] Thin Pro CA (GPMR6002)

    • 1 oz. [30g] Medium Pro CA+ (GPMR6008)

    • CA Applicator Tips (HCAR3780)

    • CA Activator 2 oz. [57g] Spray Bottle (GPMR6035),

    • or 4 oz. [113g] Aerosol (GPMR634)

    • Pro 30-Minute Epoxy (GPMR6047)

    • Milled Fiberglass (GPMR6165) -OR- Microballoons

    • (TOPR1090)

    • Threadlocker Thread Locking Cement (GPMR6060)

    • #1 Hobby Knife (HCAR0105)

    • #11 Blades (5-pack, HCAR0211)

    • #11 Blades (100-pack, HCAR0311)

    • Drill Bits: 1/16" [1.6mm], 5/64" [2mm], 3/32" [2.4mm],

    • 7/64" [2.8mm], 1/8" [3.2mm], 5/32" [4mm], #29 Drill and 4-40 Tap (or Great Planes 4-40 Tap and Drill

    • Set (GPMR8101)

    • Tap handle (GPMR8120)

    • Soldering Iron or Hobby Heat Micro Torch II

    • (HCAR0755)

    • Silver Solder w/Flux (GPMR8070)

    • Denatured Alcohol for Epoxy Cleanup

    • Plastic-Compatible Oil for Hinge Pins

    • Rotary Tool and Cutting Bits (See Page 20)

    • Rotary Tool Reinforced Cut-Off Wheel (GPMR8200)

    • Fine-point felt-tip pen (Top Flite Panel Line Pen?

    • TOPQ2510)

    • Black Paint for Cockpit Interior

    • Medium-Grit (220 - 320-Grit) Sandpaper

     

    OPTIONAL SUPPLIES AND TOOLS

    • Here is a list of optional tools that are also mentioned in the manual.

    • Epoxy Brushes (6, GPMR8060)

    • Mixing Sticks (50, GPMR8055)

    • Mixing Cups (GPMR8056)

    • CA Debonder (GPMR6039)

    • Dead Center Engine Mount Hole Locator

    • (GPMR8130)

    • Curved-Tip Canopy Scissors for trimming plastic parts (HCAR0667)

    • Non-Elastic String for stab alignment (such as

    • K&S #801 Kevlar thread or fi shing Kevlar thread)

    • 9/32" [7mm] O.D. K+S brass tube for fueling line

    • (See page 22)

    • Masking tape (TOPR8018)

    • 3M 77 Spray Adhesive (MMMR1990)

    • AccuThrow Deflection Gauge (GPMR2405)

    • CG Machine (GPMR2400)

    • Laser Incidence Meter (GPMR4020)

    • Precision Magnetic Prop Balancer (TOPQ5700)

    Covering and Tools:

    A covering iron will be required for tightening the covering on the model after it is removed from the box. Following are the covering tools recommended:

    • Coverite 21st Century Sealing Iron (COVR2700)

    • Coverite 21st Century Iron Cover (COVR2702)

    • Coverite 21st Century Seal Iron (COVR2750)

    The Top Flite B-25 ARF is factory covered with Top Flite MonoKote fi lm. Should repairs ever be required, following is a list of colors used on this model and order numbers for 6' [1.8m] rolls.

    • Flat Olive Drab (TOPQ0510)

    • Flat Dove Gray (TOPQ0511)

    • Flat Black (TOPQ0508)

    • Jet White (TOPQ0204)

     


    Unpacking The Box

    Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box

    The box that the B-25 comes in is just plain big. I was glad that I was in my truck the day it got delivered because it took up the entire bed of the truck to haul the box home. The outside of the box has full color prints of the plane, all the specs for the plane, plus the requirements to get the plane up and flying. Opening it up will reveal a box very full of parts. Everything it tightly packed into the box, but is still well protected from damage from rough handling of the box. When it comes time to unpack the box make sure that a large area is available as there are a LOT of parts in this plane. As I unpacked the box it seemed like every surface of my dining room and kitchen was covered in B-25 parts. It would be really hard to show all of the parts included with this plane because of the amount of space involved, but I'll try to hit on some of the highlights to give everybody a good idea of what to expect. All of the major assemblies (wing tips, horizontal stabilizer, vertical stabilizers, and the inboard wing sections) come with their mating control surfaces taped in place. I found it easier to keep all of these pieces taped together until I was ready to work with them.

    Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box

    All of the plastic and fiberglass parts are individually packed and wrapped in plastic to protect them. The plane is shipped with wheels that are made of foam rubber. I was a bit disappointed to see such a high-quality plane provided with foam wheels and would have rather seen rubber wheels provided. With the scale parts unwrapped it's easy to see that they are high quality parts.

    Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box

    Laying out all of the "parts" bags reveal a LOT of parts. Included with the B-25 are full color self-sticking decals. While not included with the plane itself, I wanted to lay out all of the electronics needed for the B-25.

    Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box Top Flite  B-25J Mitchell ARF - Unpacking the box

    With a plane the size of this staying organized is really an important part in assembling the plane. Along these lines I've included a couple of pictures of some of the things I do to help stay organized as I put a plane together. Small containers such as those shown here are a fantastic way to not only organize your parts, but they also help in keeping parts from being misplaced. Those shown here are simple pencil boxes that I found on sale at Office Depot. I always keep an eye out for items like this on sale, as I never seem to have enough of them on hand. The second item I use is a rollaway cart that I picked up at Sam's. This is great for storing all the big parts for the plane and as it's on wheels I can move it around if it gets in the way. This really helps to keep my shop organized, and with a plane the size of the B-25 organization is really going to help speed the assembly. In the last picture we see a cradle that is included with the Top Flite B-25. It is molded to fit the fuselage of the plane as is sized perfectly. It will hold the assembled plane up high enough so that the retracts can be exercised and tested, as well as providing a place to set the plane when it needs to be inverted for work or cleaning.


    The Manual*

    Top Flite  B-25J Mitchell ARF - The Manual Top Flite  B-25J Mitchell ARF - The Manual

    The manual for B-25 is 51 pages long and printed in black and white. The manual does a very good job of laying out what is needed to successfully complete the assembly of the plane as well as identifying all of the major parts of the plane. There is one thing I would have liked to see in this manual though, and that would be an identification page for all of the small hardware included with the plane. There are a lot of small screws, nuts, bolts, washers, and other hardware and having an identification page would have helped to sort it all out.

    Top Flite  B-25J Mitchell ARF - The Manual Top Flite  B-25J Mitchell ARF - The Manual

    The instructions for every step of the assembly are well written and do a great job of explaining what needs to be done. The manual also includes plenty of pictures and illustrations to help show each step.

    *Note: An online version of the manual can be found here:  Top Flite B-25J Mitchell ARF Manual



    Getting Started

    As I get started here I just wanted to stop and say that I do realize this is a really long review. It's hard to review a plane of this size and quality and keep the review short. I want to make sure that I point out everything involved with getting this plane together and flying and I do apologize for the length of the review. But trust me, stick with the review and read it all as this plane is definitely worth the time spent.

    Removing Wrinkles From Covering

    As we get started in the assembly of this plane we need to take a little time with the covering of the plane. Before we get started I want to comment on the quality of the covering job on this plane. The plane covering is expertly applied and looks great. But even the best of covering jobs is going to pick up some wrinkles over time, so we need to take care of those.

    One thing I have found working with ARF's is to never assume that the edges of the covering are completely sealed down. In the past I have started to apply heat to the covering only to see it pull away from the edges because it wasn't properly sealed. So the first step I always do is to use a covering iron, or trim iron for the tight spots, and seal down all the edges of the covering for all of the assemblies of the plane. On most ARF's I don't usually use a heat gun to shrink the covering, but rather I will use it to find the areas where the covering its fully adhered to the structure beneath it. Apply heat to the covering and you will be able to see these areas as the covering will wrinkle up in those areas. This actually is doing the same thing that the sun will do to your plane as it sits out at the field, so doing it here will help avoid wrinkles from forming when the plane is outside in the sun. Once an area that needs to be sealed down is found I use a covering iron with a hot sock on it to properly seal the covering down to the wood beneath it.

    For smaller areas such as the control surfaces I will usually just use the covering iron and go over the entire surface to seal the covering. As you can see in the above picture I did have one small problem with the plane, one section of this flap was "crunched" in a bit. I didn't make a big deal of it though as it was a very simple repair. I used a small syringe to shoot some water into the wood of the crushed portion of the flap. Then I use the covering iron to heat that area. The iron will heat up the water which expands the wood back into shape.


    Assembly of the Wing Panels

    The ailerons and flaps for this plane use Robart Hinge Points, which I much prefer over CA hinges, so I was very happy to see them used on this plane. There are two sizes of hinge points used on the wing with the smaller size being used for the ailerons and the larger size used for the flaps. Before installing the hinges it's a good idea to put a drop of oil into the hinge itself. This will prevent epoxy from getting into the hinge as they are installed in the wing. I prefer to use 30-minute epoxy when installing items such as this as it will give plenty of time to get everything installed and set properly before the epoxy sets. After mixing the epoxy I used a small pin to apply epoxy into each hole for the aileron in the wing.

    With epoxy in each hole I pushed a hinge point into each hole in the wing. After pushing each hinge point into the wing use a paper towel to clean up any epoxy that squeezed out when inserting the hinge point. Next put epoxy into each hole in the aileron in the same manner and then install the aileron to the wing.

    The flaps are installed in the same manner as the ailerons. With the flaps and ailerons installed insure that they are positioned properly on the wing before the epoxy sets, and make any adjustments needed.


    Mounting the Engines, Throttles, and Fuel Tanks


    The engines, fuel tank, throttle servo, and landing gear for each wing is installed into a nacelle structure that can be removed from the wing. I really like this design as it made it easy to install components in the nacelle for each wing. The nacelles are then attached to the wing with 4 nylon bolts.

    I found early on that it was beneficial to identify each nacelle and label them in order to not mix them up while working. While it's next to impossible to install the wrong nacelle on the wing it just made things easier to be able to quickly identify each nacelle.

    Install 2 nylon alignment pegs into the nacelle. These need to be epoxied in place with 3/4" of the bolt exposed above the nacelle.

    Place the nacelle on the wing and secure using 4 2" nylon bolts.

    Located in the back of the manual are templates for drilling the engine mounting holes in the firewall. Provided are templates for both 2 and 4 stroke engines. The template is cut out and placed on the firewall to mark the mounting holes. When marking the firewall make sure that the template is oriented properly as indicated on the template.
     

    OS-FL70 4-Stroke Engine

    Price: $179.97
    Displacement:
    0.699 cu in (11.45cc)
    Bore: 1.091 in (27.7mm)
    Stroke: 0.748 in (19.0mm)
    Practical RPM: 2,300 - 12,000 RPM
    Power Output: 1.1ps/11,000 RPM
    Weight: 18.3oz (519g) All Parts included
    16.5oz (467g)
    Recommended Props:
    Sport & Aerobatic - 12x7, 12.5x7 and 13x6
    Trainer & Scale - 12.5x7, 13.6-7

    It's a breakthrough in R/C engine technology: the performance of a 4-stroke, but with less maintenance. The FL-70 allows airplane modelers to enjoy higher torque, greater fuel economy and more realistic sound, in an engine that boasts a clean, efficient design. With the FL-70, there's no longer a need to fear 4-stroke sophistication - making it easy to step up to the benefits!

    Features

    • All components at the rear of the engine are fixed, which reduces overall costs and maintenance.
    • The newly designed 60W airbleed carburetor is easy to adjust.
    • The front bearing is sealed to prevent oil leaks
    • Also comes with a lightweight, compact F-4030 silencer and #F glow plug.
    • Approximately 20% lighter than the FS-70SII owing to a plastic cover plate, redesigned mechanism and smaller number of parts
    • Easier handling 60W airbleed-type carburetor
    • Ringless piston/liner set for easier maintenance
    • Redesigned muffler pressure system for stable power and response regardless of fuel level in tank
    • Two year limited warranty
       

    Includes

    • One O.S. Max FL-70 4-Stroke Engine with F-4030 silencer
    • One T-fitting (for easier re-fueling)
    • One type F glow plug, OSMG2692
    • One instruction booklet
    • One O.S. decal sheet

    View online manual for the OS FL-70

     

    With the mounting hole locations marked drill the mounting holes using a 5/32" drill bit. Install a 4-40 blind nut in the backside of the firewall in each mounting hole using a 4-40 allen head screw and a couple of washers to pull the blind nut into the wood of the firewall. After all the blind nuts are installed used thick CA, or epoxy, to secure the blind nuts in place so they will not come loose.

    Mount the engine mount to the firewall. The next step is to establish the proper location for mounting the engine on the engine mounts. Clamp the engine to the engine mount and then position the engine so that the front of the drive washer of the engine is located 5" from the firewall. And with this step I had a big problem. With the OS FL-70 engines I could not move them far enough forward so that the drive washer was 5" from the firewall. The physical dimensions of the engine just wouldn't fit. To correct this problem I cut a spacer out of 1/4" ply that was the same shape as the bottom of the engine mount. This spacer would move the engine far enough forward to properly mount the engine.

    With the engine mount back in place use clamps to temporarily hold the engine in place on the engine mount. Now position the engine so that the front of the drive washer is 5" from the firewall. If an old spinner with a flat backplate is available it will aid in making the proper measurement for the engine location. Simply install the spinner backplate on the engine shaft and then measure 5" from the firewall to the backplate. When the engine is in place mark the mounting holes. I prefer to use the Hobbico Dead Center tool, as it will give an accurate marking of where to drill the mounting holes. With the mounting holes marked remove the engine from the mount. Drill and tap the mounting holes using a 4-40 tap.

    With the mounting holes drilled and tapped use the included 4-40 x 3/4" socket head screws, # 4 lock washers, and #4 flat washers to mount the engine on the mount. The engine nacelles have 2 places in them to mount the throttle servos in order to accommodate different engines that can be used on this plane. With the location of the needle valve I would have preferred to have reversed the carburetor on the engine so that I could run the throttle pushrod through the bottom of the engine nacelle, as well as have the needle valve extension exit through the top of the cowl. But unfortunately the FL-70 engine does not have a reversible carburetor so I had to "make do". Luckily the two different servo mounting locations made it pretty easy to accomplish this. I mounted the servo at the rear servo location in the nacelle, which would allow the pushrod to travel along the top of the nacelle. This would mean that the pushrod would be routed so that it was between the fuel tank and bottom of the wing surface, but this was not a problem as there was plenty of room for the pushrod. I mounted the servos by drilling out the mount holes, cutting threads with a mount screw, and then hardening the threads with the CA. With the position of the servo in the mounting hole it was a bit difficult to get a screwdriver on the servo arm screw as well as the two outer servo mounting screws. I drilled holes in the nacelle in the area of the servo so that these screws were accessible. The pushrod consists of 4-40 threaded pushrod with a nylon clevis that attaches to the throttle servo, and this is routed through the firewall to the servo arm on the carburetor. Before going any further it would be a good idea to check your servo set up at this point. Later on it will be difficult to access the servo and pushrod to make any adjustments, so it's best to do it now while everything is easy to access.

    The plane includes 2 fuel tanks, one for each engine, which has a capacity of 14.2 oz (420 cc). The included hardware provides enough material to set up a 3 line system which will allow the tanks to be fueled and de-fueled without having to disconnect any of the fuel lines connected to the engine. This is needed because all the plumbing for the engines are inside of the cowling. The tank assembly is pretty standard. The rubber stopper is sandwiched between two metal plates and 3 aluminum tubes run through the stopper. The upper tube is bent towards the top of the tank, which will be used as the vent for the tank, which will be connected to the muffler pressure line. The other two tubes will be connected to fuel line with a clunk on each line at the back of the tank. One line is the fuel pickup, which will provide fuel to the carburetor. The other pickup line is actually the fill line, which will also be used to de-fuel the plane. Once the stopper assembly is completed it is inserted into the hole of the fuel tank.

    The stopper assembly is held in place by tightening the screw in the assembly. When I assemble a tank I like to label each tube so that I don't get mixed up later on as I assemble the plane. The tank is then inserted into the engine nacelle directly behind the firewall. When installing the fuel tank make sure that the vent line is at the top of the tank when the tank is held in the correct position.

    The fuel tank is held in place by 2 ply strips that are inserted in the pre-cut slots in the engine nacelle, one at the bottom of the tank and one at the end of tank. Put a small drop of thick/medium CA on each strip to hold it in place. The picture above shows the completed nacelle and installed engine. The last thing to do at this point is to route the throttle servo wire through the wing. Make sure the wire is labeled. Trust me in that this is very important to do as we continue on into the assembly of this plane. There are a lot of servo wires used in this plane and if they aren't all properly labeled it will lead to a lot of confusion later on, so it's better to label them and keep them straight as we go along.


    Main Landing Gear

     As the landing gear are installed it's important to choose the colors of your air tubing. It doesn't matter what color you use for each function (gear up and down) but it is important that all retracts are connected in the same manner. To start off cut off approximately 21" of the line used for "up" and 18" for the "down" line. Connect these lines to the air cylinder of the retracts with the "down" line connecting to the air fitting that comes out of the end of the cylinder, and with the "up" line connected to the other air fitting. Place the retract unit in place on the engine nacelle. As the location for the mounting screws is marked it's important to push the retract unit as far to the rear of the recessed mounting area as possible. This is done to ensure that the landing gear strut clears the nacelle cover when it is installed later. Mark each location of the mounting hole and then drill the holes with a 7/64" drill bit. Use one of the mounting screws to cut threads into this mounting hole.

    Use thin CA to harden the threads that were cut into each hole. When the CA has fully cured mount the retract unit in place using #6 x1/2" Phillips head screws.

    Route the airline from the end or the air cylinder back into the nacelle structure using the pre-drilled hole. Slide a wheel on to the wheel axle and install it in place in the landing gear strut. Mark the location of the setscrew on the wheel axle and grind a flat spot on the axle. I found that a Dremel tool with a flat cutoff wheel is the easiest to accomplish this.

    Reassemble the wheel on the axle and install in the gear strut. Place threadlock on the setscrew and tighten to secure the wheel axle in place. Put a drop of oil on the wheel at the axle to ensure that is moves freely. Use a can of compressed air to verify that the retract mechanism functions correctly.


    Mount the Fiberglass Nacelle Covers

    Before mounting the fiberglass nacelle covers the engine needs to be removed so that the nacelle cover will fit over the nacelle. Make sure the correct nacelle cover is used, as there is a left and right cover. The easiest way to tell the difference is the notch cut out for the landing gear strut. To mark the mounting holes for the nacelle cover I found it easier to use painter's tape to hold the cover in place as I marked the mounting hole. Use a Dead Center marking tool to mark the position of the mounting holes on the wing. Remove the nacelle covers and use a 3/32" drill bit to drill the mounting holes. Use a 1/8" bit to enlarge the mounting holes in the nacelle cover.
     

    Use the #4 x 5/8" Phillips head screw to cut threads in each of the drilled mounting holes and then use thin CA to harden these threads. When the CA has cured use #4 x 5/8" Phillips head screws, #4 lock washers, and #4 flat washers to mount the nacelle cover to the bottom of the wing. A long shaft screwdriver is essential to mount the nacelle cover. I found the easiest way to do this was to shine a flashlight on the mounting screw from the landing gear bay, and then look through the crack between the firewall and the nacelle cover to place the screwdriver on the head of the screw.
    Don't worry if it feels clumsy putting this nacelle cover in place on the wing, because you're going to get a lot of practice as the assembly of the plane continues. The nacelle cover will be put on and removed several times as we continue.


    Mount the Main Landing Gear Doors

    Working gear doors have always been a bit difficult to design and implement, but Top Flite has done an outstanding job of accomplishing this very task. Their design for working gear doors is very well done and very sturdy.


    The first step to installing the gear doors is to remove the nacelle cover from the wing. Locate the areas on the inside of the gear doors where the hinges will mount. Use a hobby knife to scrape away the black paint where the hinges will mount to the gear doors.

    Use tape to secure the gear doors in place on the nacelle cover. At this point I found I had a problem with one of the gear doors as it was pretty warped and would not mount correctly on the nacelle cover. I was able to correct this by running hot water over the gear door to heat it up. Then I twisted the gear door in the opposite direction of the warp. A few minutes of doing this straightened out the gear door so it fit flush on the nacelle cover. Use a razor blade to cut off 1/8" from two nylon ball links, then use a 5/64" drill bit to drill out the inside of the ball link. These hinges will be used for the rear of the gear doors. Now cut 1/6" off of two ball links and construct two more hinges, which will be for the front of the gear doors.

    The ball links are mounted to the door hinges using 2-56 x 3/8" screws, # 2 lock washers, and #2 flat washers. The orientation of the hinges is very important so make sure to refer to the instruction manual as they are installed in the plane. Four nacelle hinges are constructed by mounting 0-80 ball link ball in the bottom hole of each hinge using a 0-80 nut and a drop of threadlock to secure the nut in place. Be careful here as I had one ball link shaft break off as I was tightening down the nut, which caused me to be short at the end of the assembly of the plane. Build two "A" hinges and two "B" hinges, referring to the instructions as a guide for doing this. Referring to the pictures in the instruction manual use coarse sandpaper to roughen the inside of the nacelle cover where the gear door hinges will mount


    Use 30-minute epoxy mixed with microballons to glue each hinge assembly to the gear doors where the paint was scraped off earlier. After the epoxy has set repeat this to glue the hinge bases to the inside of the nacelle cover. After all of the epoxy has set remove the tape from the outer doors and ensure that the gear doors open and close freely. If any epoxy has "oozed" out so that it interferes with the closing of the gear door it will need to be removed.

    If for any reason the gear doors need to be removed it's important to NOT pop the ball links off of the ball mounts. If the door needs to be removed unscrew the door hinges at the ball link and remove the gear door this way.


    Hooking up the Main Landing gear

     Glue a 1/8" x 1/2" hardwood dowel into a lever mount, with the end of the dowel should be flush with the backside of the lever mount. Hold the lever mount on the back side of the nacelle so that the outer edge of the lever mount is flush with the side of the nacelle, and the top flat portion of the lever mount is flush with the top of the nacelle. Use a 1/16" drill bit to drill a pilot hole for the mounting screw. Remove the lever mount and use #2 x 3/8" button head Allen screw to cut threads in the pilot hole and then harden the threads with thin CA. When the CA has dried install the lever mount in place using the button head Allen screw. Use the second hole in the lever mount to drill a pilot hole using a 3/32" drill bit; this hole will be to mount the bell crank. Use a #4 screw to cut threads in this hole and then harden the threads with thin CA.

    A wooden bell crank that is made out of hardwood ply operates the gear doors. While the original wood doors are very durable some may find that repeated use over a long period of time may wear out the wooden doors. With this in mind one of our RCU members had made available a set of aluminum bell cranks that can be used in place of the stock wooden ones. They are available for a cost of $10, which includes shipping. If you are interested contact RCU member Mike-Rc (gear doors may be found here) to get a set of these bell cranks. I picked up a set so that I could show them here in this review.

    To install the bell crank first glue a plastic washer to each side of the bell crank using thin CA. Now fit a brass bushing into the bell crank and install it in the lever mount using a #4 x 5/8" screw. Tighten the screw tight enough to hold the bell crank in place, but it still needs to be able to move freely. Bend a hook in each end of the provided spring approximately 3/8" from the coils of the spring. One end of the spring is hooked through the hole in the bell crank, and the other end is hooked into one of the notches in the lever mount. Start in the middle notch, but this can be adjusted if needed for better operation of the gear door. Test the operation of the landing gear in that it moves freely and does not bind. If needed trim the bell crank in order to provide free movement of the landing gear strut. Cut a 4" pushrod so there is 3/8" of thread remaining and then a total length of 2-1/2". Bend the pushrod to match the diagram provided in the instructions.

    At this point I was a bit perplexed in constructing the other gear door pushrod. The instructions do not mention what to use to build this. I finally a found small piece of threaded rod that is used for this in the bag that contained all of the screws, but it took me some time searching to find this. Once the pushrods are constructed use epoxy mixed with microballons to glue control horns to the inside of the gear doors, attach the pushrods to the bell crank and use this as a guide in placing the control horns.

    Attach each gear door and work the retracts to adjust the length of the pushrods so that the gear door completely closes without binding. I found it easier to disconnect one door to adjust the pushrod of the other door. With both doors adjusted use a can of compressed air to cycle the landing gear and make sure that the gear doors completely close without binding.

    These pictures can be used as reference for the workings of the landing gear and gear doors.


    Mount The Cowl

    Once again, the nacelle cover needs to be removed for these next steps. Use 5/32" drill bit to drill holes through the firewall at the 8 precut marks for the cowl mounting tabs. As you can see in the picture place something solid behind the firewall when drilling the holes to prevent accidentally drilling holes in the fuel tank. Use a 4-40 x 3/8" Phillips screw and 2 #4 washers to pull the blind nuts in place in each of the holes that were just drilled. Use thick CA to secure the blind nuts in place, making sure to not get any glue in the threads of the blind nuts. There are two different sizes of cowl mounting tabs: the long ones are marked "A" and the short ones are marked "B". One of the "A" tabs will have a larger hole in the top of it. Press a 4-40 blind nut into the larger hole and use thick CA to secure it.

    Use threadlock on the screws to install the cowl mounting tabs and install each mounting tab with 2 each 4-40 x 3/8" Phillips screws, #4 lock washers, and #4 flat washers. When installing the tabs the "A" tab with the blind nut in it is installed at the top of the firewall, with the blind nut to the rear. Install the remaining tabs so that the blind nuts are to the front of the nacelle. In the cowl ring there are 3 larger holes pre-drilled and one smaller pre-drilled hole. Install 3 4-40 blind nuts in the 3 larger holes.

    When installing the 4-40 socket head screws that mount the cowl it's important to remember that when the plane is assembled it's going to be rough to get into the cowl when removing it, and therefore could lead to the screw falling out and being lost. I will admit that this is not my idea and that I picked it up from the thread about this plane here on RCU, but use fuel tubing to retain the screw in place. Insert the 4-40 x 1/2" socket head screw, #4 lock washer, and #4 flat washer through the mounting tabs (and through the cowl ring for the tab at the top of the cowl) and then slide a small piece of fuel tubing over the screw. Now when the cowl is removed the fuel tubing will keep the screw from falling on the ground and being lost. As you can see it is about impossible to get an Allen wrench straight on to the cowl mounting screws, so a ball end wrench is mandatory for this plane. The ball end will allow the screws to be turned from an angle so that the cowl can be removed. And as you'll see later a long shaft wrench is needed as well in order to access the one screw at the top of the cowl ring. Great Planes makes a set of ball drivers that are perfect for this application, the part number for these can b found in the instruction manual. As can be seen above, the cowl ring is mounted on the mounting tabs.

    Leaving the cowl ring in place cut the ring so the engine muffler can be installed on the engine. The cowl now needs to be rough-cut in order to allow it to slip over the head of the engine. Use a cutting wheel on a rotary tool to rough cut this hole. The hole will be cleaned up later on as we finish up the installation of the cowl.
     

    For the next step the inboard portion of the wing with the nacelle needs to be mounted on the fuselage. Slip the three wing tubes through the fuselage and slide the inboard wing section in place. I placed a small board across the wing tubes on the other side of the fuselage and placed some weight bags on the boards to counter the weight of the wing section. This let the fuselage sit level. Position the fiberglass carburetor intake in place on top of the wing and mark the position of the mounting holes. Use a 1/16" wrench to drill mounting holes, cut threads in each hole with the #2 x 3/8" Allen Head Button screw, and then harden the threads using thin CA. When the CA has cured install the carburetor intake using #2 x 3/8" Allen head button screws.

    Now slide the cowl into position on the nacelle. As you can see in the picture above there is quite a bit of down thrust built into the engine mounts. Because of this the user will need to make a compromise between centering the propeller in the cowl and aligning the cowl with the nacelle cover. The user needs to position the cowls so that they look "about right". Looking at the cowl from different angles while doing this will help to get it positioned correctly. When satisfied with the position use thin or medium CA to tack the cowl to the cowl ring.

    Without breaking the cowl ring free from the cowl carefully remove the cowl. Use 30-minute epoxy mixed with microballons or milled fiber to build a fillet all the way around the cowl ring on both sides of the ring. When dried remount the cowl and cut an access hole in the top of the cowl that will be used to insert a ball driver to access the mounting screw. With the cowl mounted now cut the cowl in order to allow the muffler to be mounted. Also clean up the hole cut for the engine, ensuring to add a hole for the glow diver to be attached to the engine.

    Since this is a 3-line fuel system a mount in the cowl is needed for the fill line. Included with the plane is an end for the fill line, so we need to build a mount in the cowl. This is actually very easy to do with a scrap piece of balsa and 9/32" brass tube. Cut the scrap balsa to approximately 1" square and shape one side to fit the curve on the inside of the cowl. Drill a 9/32" hole in the middle of the block and insert the brass tube. The tube needs to be cut so that it just extends to the outside of the cowl. This is then epoxied into the plane inside the cowl. To mount the replica engine first sand the side of the replica to remove the paint from the plastic.

    Cut out two of the cylinders from the replica. This is to allow air flow through the replica to the "real" engine inside of the cowl. On the remaining cylinders us a small drill bit, or the tip of a hobby knife, to make small holes for the replica pushrods. Each cylinder has 2 pushrods on it. Insert the replica pushrods and put a drop of medium CA on the inside of the replica engine to hold the pushrods in place. Next mount the replica engine inside of the cowl so that it sit evenly in the cowl. Use thin CA to secure it in place. If needed, enlarge the hole around the center of the replica engine in order for the "real" engine to sit without rubbing or vibrating against the replica.

    The last bit for installing the cowl is to install a needle valve extension. As you can see in the pictures I had to have my needle extension exit at the bottom of the cowl. I really didn't want to do it this way, but because I couldn't reverse the carb on the FL-70 engines I didn't have much choice. I used a tried and true technique for installing items such as this. First tape a strip cut from a file folder to the nacelle behind the cowl. Position the needle extension and make a hole in the file folder. Without moving the strip of folder install the cowl into position and then transfer the hole to the cowl. Drill the cowl to install the needle valve extension.


    Hook up Flaps and Ailerons

    As you can see in the picture above there are a lot of servos in the wing (in fact there are two more servos for the throttles as well, for a total 8!). The flaps and ailerons all use standard servos. The mounts for the servos are all pre-constructed with the wood mounting rails already glued to the hatches. I did find a couple of the glue joints to be a bit loose, so it would be a good idea to run a bead of medium CA around the base of each servo rail just to make sure it's secure. One mistake I see a lot in mounting servos is that many times they will be mounted directly to the wood in installations such as this. This is not a good idea because that contact with the wood will directly transfer vibrations to the internals of the servo. If direct contact such as this occurs it bypasses the benefits that the servo grommets give. To avoid this contact I will place a small metal ruler between the servo and the hatch when marking the mounting holes. This gives enough separation to keep vibrations out of the servo. Mark the holes with a Dead Center marking tool and drill the mounting holes with a 1/16" drill bit. I like to use #2 servo mounting screws from www.microfasteners.com for mounting servos, as the socket heads in these screws aren't prone to stripping like regular screws are. After using a screw to cut threads in the mounting hole the threads are then hardened with thin CA.

    The servo is then mounted to the hatch. The hatches are mounted into the wing using #2 x 3/8" Allen head button screws. As with all other screws in wood the threads are hardened with thin CA prior to mounting the screw in the hole. For each aileron a 6" servo extension is added to the servo wire. Heat shrink tubing is provided with the plane and should be used on all connections such as this to prevent the joint from pulling apart. Simply slide the heat shrink over the joint and heat it with a heat gun to shrink the material. Although the instructions say to use a heat gun or lighter to shrink it I would advise against using the lighter. I have used them in the past and it's possible to melt and distort the servo connections if too much heat is applied. This is why I prefer to use the heat gun. As with the throttle wires, make sure each wire is properly labeled.

    With all the servo hatches in place the pushrods for the ailerons and flaps need to be installed. The TF B-25 includes solder clevises for all the pushrods, which I really liked to see. To install the control horns first use a ruler to mark their location on the control surface. When mounting the control horns the ailerons are mounted 3/16" from the edge of the aileron and the horn on the flaps is 3/8" from the edge. One thing I do want to point out is that even though backs for the control horns are provided they are not used to mount the control horns. The horns are mounted by directly screwing in #2 x 3/8" Phillips head screws into the control surface. I like to use a couple of craft sticks and two clamps to center a control surface such as this when I am setting up the pushrods.

    Plug the servo into the receiver and turn it on in order to center the servo and then measure the pushrod for the proper length. Use proper soldering techniques to solder the clevis on the pushrod at the length that was previously marked. Install the pushrod on the control surface.


    Assemble the Tail

    Assembling the tail starts with installing the rudders on the vertical stabilizers. These are mounted with the same smaller hinge points as the ailerons use, and are installed in the same manner. While the epoxy is setting on the rudder hinges move on to the elevator. The TF B-25 has a split elevator that is connected with an elevator joiner wire. Use a piece of sandpaper to rough up the torque arm portion of the elevator joiner wire so that the epoxy will get a better grip. Slide 2 plywood elevator joiner mounts onto each side of the elevator joiner wire. Once the mounts are on the wire use thin CA to glue the two mounts together.

    Before installing the elevator mounts to the trailing edge of the horizontal stabilizer it's very important to make sure that it is straight. Slide each elevator half onto the joiner wire and place on a flat surface to see if the wire is straight. If both sides don't sit flat then bend the joiner wire until both sides do sit flat. Cut away the covering on the trailing edge of the stab and epoxy the elevator joiner mounts to the stab. While the epoxy is mixed use a little bit to install the stabilizer dowel in the hole in the front of the horizontal stabilizer.

    Install the elevator hinge points in the same way as all others already installed. When installing each elevator halve also put a bit of epoxy into the hole for the elevator joiner wire. Install both elevator halves and set aside until the epoxy sets. While the epoxy is setting install the rudder servos into each servo hatch in the same manner as the aileron and flap servos were installed.

    When the elevators are set install the rudder servos into each hatch using #2 x 3/8" Allen head button screws. Use the string that is installed in the stabilizer to pull the rudder servo wires to the middle hole. Use heat shrink on the connectors and connect each rudder wire to each side of a Y-harness, and then connect the Y-harness to a 24" extension that will run to the front of the fuselage. The vertical stabilizers are installed using 2 4-40 x 3/8" socket head screws on each stabilizer. Use a bit of threadlock on each screw before installing them. Next install the rudder control horns on each rudder; this is done in the same manner as the ailerons were done.

    The rudder pushrods are built from threaded rod with a metal clevis on the servo end and a nylon clevis on the rudder side. Connect the rudder servos and center them before installing the rudder pushrods. The elevator servo is the only high torque servo used on this plane, and is installed in the precut servo mount in the horizontal stabilizer. Mark, drill, thread, and harden the mounting holes the same way as the rest during this installation. The pushrod is soldered together in the same manner as the aileron pushrods.

    A tube is provided to run the servo wires to the front of the airplane. However, I had a hard time getting the wires all the to way the end of this tube, so I ran the wire inside of the fuselage instead. The tail assembly is installed by inserting the front dowel pin into the hole in the fuselage. The tail assembly is secured using 4-40 x 1-1/2" socket head screws, #4 lock washers, and #4 flat washers. I put a bit of threadlock on these bolts as well as a little added insurance to keep the tail securely attached to the plane.


    Mount the Nose Gear

    The nose gear is controlled by a separate servo mounted in the bottom of the fuselage behind the cockpit. The nose wheel is connected to the servo by two steel cables that steer the nose wheel. The steel cables are connected to a brass coupler, which will be screwed into a metal clevis that will connect to the servo arm. To assemble the wire first slide a copper swage over the wire, through the brass coupler, and then back through the swage. Use pliers to crimp the swage and secure it on the steel wire loop. I found the swage to be very small and I had a very hard time getting the second wire into it.

    Install the steering servo into the mount at the bottom of the fuselage. The steering wires are routed to the nose wheel bay through two plastic guide tubes.

    Disassemble the nose gear strut and file a flat spot on the rod to help the setscrew hold tightly. Reassemble the nose gear and set the retract mechanism into the gear bay. Mark the location for the mounting holes, then drill and cut threads in the same way as the main landing gear was done. Use #6 x 1/2" Phillips screws to mount the nose gear in place.

    Shown in the picture is the 0-80 ball link that broke earlier as I was installing the main gear doors. Because of this breaking I was short one ball link. According to the instructions two ball links are installed on each side of the nose gear strut and the steering wire is then looped over it to steer the gear. I had to do it a bit differently because I was one ball link short. What I did was to simply loop the wire through the holes on each side of the nose gear strut. Also, as this area was really tight I didn't feel that I could get the brass swage threaded with both wires. I cut two 1/16" diameter brass tubing and used that to crimp on the steering wire. The axle for the nose wheel will need to be cut off with a cut-off wheel on a rotary tool.

    While not absolutely necessary, the hinge wells for the front gear door can be painted grey to match the color of the covering. I used paint intended for plastic models, as this is what I had on hand to do the job. The hinges for the front gear door are spring-loaded and should spring to the "open" position for the door. This is because it's actually the spring action that opens this gear door and not the motion of the landing gear. The gear strut will engage a wooden lever which will pull the door shut as the gear retract. The lever is constructed with a 2-56 ball link bolted in place in the pre-drilled hole and a 4-40 x 1" socket head screw used as a pivot point. The socket head screw is inserted through a brass bushing before it is put through the lever.

    Use epoxy to glue the front gear door in place. Place epoxy on each side of the spring loaded hinge and install the gear door to the fuselage. While the epoxy is setting up tape the gear door in place. Use something to insert into the gap between the fuselage and the gear door. Here I used two nail files that I had on hand, as they were the perfect thickness. Once the epoxy has set use medium CA to glue a control horn on the inside of the gear door. This will attach with a pushrod to the gear door lever. Retract the landing gear and then use a long shank ball driver to adjust the linkage. Cycle the front gear to ensure the proper movement of the landing gear and gear doors, and make any necessary adjustments.


    Assemble the Cockpit

    NOTE: In the initial run of kits for this plane there was a misprint on the needed air tank if Robart retracts are being use. While the plane was originally designed to use a small air tank, the stock number listed in the instruction manual is for the large air tank available from Robart. Actually, it may be better to use the larger air tank as it will give more retract cycles than the smaller air tank will. The plane was designed to have the small air tank installed just forward of the cockpit, but the larger tank will not fit into this location. If using the large air tank the area directly behind the cockpit is the perfect location to place this tank. Top Flite has a template for making mounts on their website.

    The cockpit is assembled by first gluing two 3/16" x 3/16" x 5" balsa sticks to each side of the cockpit, just slightly above the edge of the front shelf in the cockpit. Using the cockpit floor as a guide drill 4 1/16" pilot holes in the balsa rails. Use Allen head button screws to mount the cockpit floor. Use black paint to paint the parts of the cockpit that will be visible when the plane is assembled.

    The instrument panel is made from the two instrument decals, the plastic instrument panel back piece, and the wooden instrument. Use spray adhesive to attach the decal with the instrument dials to the front of the black plastic panel back piece. Trim off any excess around the edges of the panel. Now glue the wooden piece on top of the panel decal. Finally, place the last decal over the top of the wooden panel middle, lining up the holes in the instrument panel with the dials below. The pilot figures are simply profiles of a pilot. Cut the appropriate decals and attach them to the wooden pilot profiles. Glue the 2 full size pilots to the cockpit floor by CA'ing them into the provided slots. Complete the cockpit by adding the seat backs and the control yokes to the cockpit. At this point the cockpit floor will be removed until the plane is put back together for final assembly.

    The mount for the retract air control valve is made from the supplied ply parts. Assemble the mount and secure the air control valve. Install a 0-80 ball link ball on the control shaft of the valve. Mount the retract servo and the air control valve beneath the cockpit on the right side of the fuselage. The retract servo needs to be adjusted so that it has no more movement than 1/4" of travel.

    Provided are two ply mounts that will serve to hold the receiver in place beneath the cockpit floor. Install these with medium CA. There are 4 slots in the floor to glue these mounts in, so you can tailor it to fit your specific radio gear. Use the supplied parts to build the air fill valve mount. Mount the fill valve in the mount and adjust it so that the end of the fill valve is 7/32" from the top of the ply side rails. With this build install this in the plane on the left side of the fuselage in the pre-cut mount hole. The air fill valve should be installed so that it sits flush with the outside of the fuselage side.

    Use epoxy to glue the air fill valve in place. Included are several wire management "loops" that can be used to tame down all of the wires and air lines that will run in the fuselage of this big bird. One of these guides is glued in place behind the retract servo, but the other guides can be placed as needed. One thing I found that really helps keep down the clutter is to join each set of retract lines together. I do this by using small pieces of fuel tubing slipped over the lines to hold them together.

    The receiver is wrapped in foam rubber and then mounted in the cockpit area. Air lines for the main gear are run back through the fuselage and then a "T" fitting is used to branch out to each main landing gear. Quick disconnects are provided with the plane to facilitate removal of the wings if needed. Here you can see the completed cockpit area.


    Radio Installation

    For the review of the Top Flite B-25J Mitchell I had the opportunity to try a new product that I have not seen before. These are new power systems from Duralite batteries. These systems are unique as they are Lithium chemistry batteries that are regulated down to the voltage of the receiver that is being used. Because of this there is a constant voltage available to the receiver even when the battery drained. These batteries also have the advantage for being able to handle large current draws from the servos and flight system in today's modern planes.

    The setup of these batteries is a bit different than some people may be used to. The battery itself is a 2-cell Lithium-Manganese battery that has 2 wire sets coming out of it. The heavy gauge wire is the power tap and this is plugged into the voltage regulator. The second wire is the charge lead which will be used to recharge the battery. The second component is the voltage regulator. This is plugged into the power tap from the battery. The regulator has it's own power switch that is used to turn on power to the system. There is a jack attached to this switch which is used to check the voltage level of the battery. Duralite has an adapter available that will go from the voltage regulator into your radio system. All power connections in these systems utilize Deans connectors to handle the higher voltage loads on the system.

    Duralite Lithium-Manganese Receiver Batteries

    • Non combustable chemistry

    • Non flammable if punctured or overcharged

    • Highest Discharge - 20c continuous with 40c bursts

    • Great low temperature toleranace

    • High charge rates up to 10c

    • Stay Balance circuit built into pack - no need for   external balancing

    • Longer life cycles than li-polymers

    • Dual lead system - choice of power output leads/connectors, plus charging lead w/yellow connector

    2200 mah - 2 cell Li-MN -7.4 volt
    Price:
    $97.95
    Flight weight: 5.8oz (165 grams)
    Size: .5 x 1.75 x 5.5in (T/W/L)
    Discharge Amperage: 44Amp (20C)
    Charge Rate: 1AMP

    Voltage Regulator

    High Current Regulator The High Current version of the DURALITE regulator uses 16 gauge wire and the Ultra Deans connectors to reduce resistance in the wiring and the connectors which improves the regulators overall efficiency. We have found that the minimum voltage is significantly higher when the HC-wiring is used. We hope to have another graph of this same situation that will show as soon as the weather co-operates this spring.

    • Surface mounted electronic components.

    • Compact heat sink.

    • Full RF filter in and out delivers highest performance.

    • Rated at 7.5 amps with 10 amp spikes

    • Unique Hybrid Pulsing Design

    • Designed for 6 - 8.4 volts

    • Specifically designed for use with the DURALITE PLUSTM Battery but also works well with other battery chemistry types

    Voltage Regulator with Fail Safe Switch, 7.5 amp w/standard 22ga wire, 6.0 volt
    If the switch were to fail regulator stays in the on state until you unplug it from the battery. Not suitable for ignition applications due to fail safe feature.
    Price: $49.95

     

    Bringing in all of the servo leads to the receiver. Labeling each wire will help to keep them all straight and organized

    There is a tube provided to run the receiver antenna through. Use a strain relief to keep the wire from pulling out of the receiver if any pressure is placed on the antenna wire.

    The antenna wire isn't long enough to extend all the way to the tail of the plane. Tie a piece of string to the antenna wire and pull back to the tail and tie off the string. This will keep the antenna from working it's way back up the antenna tube.

    The on/off switch is mounted on the left side of the fuselage directly below the cockpit. The Duralite power system provides a jack used to check the power level of the battery. This jack is mounted here with the switch.

    Duralite battery installed where small air tank should go.

    Duralite power regulator. Zip ties used to secure regulator behind front landing gear bay.

    Radio installation completed. All components in place. Power lead from battery is routed back underneath cockpit to the voltage regulator located behind the landing gear bay. The charge jack for the battery is tied off in the landing gear bay and can simply be pulled out to charge the battery.


    Mount the Inboard Wing Panels

    The design of the Top Flite B-25J Mitchell leaves the end user with several options as to how to transport the plane to the field. The wing is actually made up of 2 sections; the outboard wing section and the inboard wing section that has the engine nacelles on it. If transportation space is limited it's possible to leave both sections off and assemble the entire wing at the field. I chose to instead install the inboard wing sections on the fuselage and transport to the field assembled as such.

    1 30 x 440 mm main wing tube and 2 10 x 305 m wing tubes support the wing sections. The smaller wing tubes are secured with 4-40 socket head screws, which also secure the wing sections to the fuselage. These tubes come with one end already tapped to accept the socket head screw. Slide these sections into the wing section and install the 4-40 x 1" socket head screw through the wing section into the wing tubes. Slide these wing tubes into the fuselage section and connect all of the wiring and air connectors. Because I plan to leave these assembled I used heat shrink on all of the connectors to ensure that they remain secure. With all the connectors in place slide the wing section all the way tight against the fuselage.

    Turn the fuselage around and slide the other wing section onto the wing tubes. Once again secure all the wires and air connections and slide the wing section tightly against the fuselage. Ensure that both wing sections are tight against the fuselage. Use brass tubing to make a small drilling jig to drill pilot holes in the wing tubes. First place a 1/8" piece of tubing into the screw hole in the wing. Then place a 1/16" piece of tubing inside of the first brass tube. Now use a 1/16" drill bit to drill a pilot hole in the wing tube using the guide to keep the drill straight. Ensure that you drill all the way through the wing tube.

    Remove the wing section and re-drill the holes in the wing tube using a #43 drill bit. Use a 4-40 tap to cut threads into the wing tube. After tapping the tube use a file to remove any metal burrs that may be left around the hole. Reinstall the wing section and secure in place using a 4-40 x 1" socket head screw. Use a drop of threadlock on the screw to secure it in place on the wing tube.


    Mount the Outboard Wing Panels

    The outer wing panels are installed in a similar manner to the inner wing panels. Wing tubes are used to support the wing using a socket head screw at the rear wing tube to secure the wing to the tube. The difference here is that a nylon bolt is used at the front of the wing to secure it. This bolt is installed at an angle along the front of the wing panel and is hidden from view by the molded plastic oil cooler. The instructions call for determining which oil cooler went on each wing, but as I looked at them I found both oil coolers to be identical. The oil cooler is placed in position on the wing and then use a marker to outline the oil cooler. Use a hobby knife to cut through the covering 1/16" inside of the line. Remove the covering from this area, leaving the black covering in place over the air scoop. Use medium CA to glue the air scoop in place on the wing.

    Install the 2" nylon bolt in the front of the wing panel and tighten it down against the inboard wing panel. Use the same method to drill and tap the wing tube as we did for the inboard wing panel. Use a 4-40 x 3/4" socket head screw to secure the wing panel in place.


    Scale Features

    Use medium CA to glue the plywood rubber band hooks on the inside of the nose-gunner window. To prepare the parts of the nose section to be joined first use medium grit sandpaper to scuff the edge of the bottom piece as well as the edges of the nose canopy. Align the parts and use tape to hold the nose canopy and bottom section together.

    The nose canopy and bottom section are joined using thin CA. Maybe it's just me, but I never have any luck using CA around clear pieces on a plane. No matter how careful I try to be CA always seems to wind up in the clear portions. I would rather use different method than had been used to construct the nose portion of the plane. I followed the instructions and use thin CA for gluing the nose canopy parts together, and tried to be very careful as I did this. However I still had CA run where I didn't want to, which resulted with CA in the clear window portions of nose canopy. When I tried to remove it with CA debonder it clouded the canopy. I was able to "clean" this up by "painting" that portion of the nose canopy with clear fingernail polish which did a pretty good job of filling in the clouded portion of the canopy. But it's still not perfect and if looked at close enough brush strokes can be seen where the nail polish was brushed on. It looks ok as long as you don't look too closely at it. If I were to do this again, or had to recommend and alternative method, I would use Formula 560 Canopy adhesive to join these parts together.

    When the nose section is complete use rubber bands to secure the nose gun into position. Glue the supports to the bottom of the nose gunner cabin platform. Also, this platform can be used to secure the battery if needed. Parts are provided to assemble a platform that glues to the underside of this section. Unfortunately I could not use this because the Duralite battery that I used was too long to fit under the platform. This is the reason why I needed to move the battery to the cockpit area of the plane.

    Glue the cabin platform into position on the plane. If Top Flite missed on anything big in this plane I would have to say it was the paint used on the scale parts. While I compliment TF for putting the parts in the plane, the colors were all off. What should have been a interior green turned out to be an almost neon green, and the leather of the nose gunner seat turned out orange. Hopefully they can correct this in later editions of this plane as I feel that correct colors would add a lot to this great warbird. Use the provided Allen head button screws to secure the cabin back wall to the structure of the plane. I made sure to install these so that I could access them later on so I could remove the back wall if any servicing is needed of parts behind the wall. Use medium CA to glue the cabin floor to the platform.

    Glue the tops of ammo boxes on the ammo boxes and then glue the boxes to the ammo tray. Then glue the ammo tray to the cabin floor as shown. I would recommend using epoxy to glue the ammo cans to the ammo tray. I initially used medium CA for this and while I was breaking-in the engines the vibrations caused them all to break loose. I reattached them using epoxy and so far that seems to be holding. Glue the kneeling pad to the post on the floor of the cabin. Position the canopy on the plane and use Allen head button screws to secure the canopy in place. Unfortunately I did not have enough of these to complete this. As I state in my summary below I had a problem with these screws "stripping" out as I installed them, even though I used several different wrenches. I used #2 socket head screws from www.microfasteners.com to install the canopy in place.

    The scale features for the tail gunner are installed in the same manner as the nose section. Scrape the paint away from plastic parts before gluing them together.

    Glue all the plastic scale parts in place including the tail gunner profile figure. I used Formula 560 Canopy Glue to install the tail gunner canopy in place. I had another issue with the tail section similar to the nose section. While breaking-in the engines the vibrations broke loose the gunner figure. To fix this I drilled through the cabin floor and used small screws to secure the figure in place in the cabin.
     

    The top turret gun is assembled from two machine gun barrels and the gun unit. Included in the kit is a circular piece of steel grey MonoKote that should be ironed down where the top turret will be mounted.

    The back edge of the top turret guns should be placed 5" behind the back of the cockpit. Mark and cut the MonoKote where the guns will be mounted and glue the guns in place. I used the Formula 560 adhesive again to glue the top turret in place on the top of the fuselage. I did have to trim the gun slots of the canopy a bit in order to get the turret to fit properly over the guns.

    Gluing machine gun barrels into each waist gun window assembles the waist gun windows. Place the waist gun window on the side of the fuselage and mark it's position. Make sure to get the windows on the proper side of the plane. It was impossible to get them wrong on my plane as the invasion strips on both the fuselage and the windows would only line up one way. Use epoxy to glue the waist gunner windows in place on the fuselage.

    The side gun packs are assembled by gluing the gun barrels into each gun pack. The instructions called for the bottom gun to extend 3-1/2" from the pack, but I was unable to do this, as there just wasn't enough gun to extend that far. I glued the gun in as far out as it would go and then matched the other gun in the pack with it so that they were even. The side gun packs are molded to fit the curve of the fuselage so they need to be mated to the sides of the plane. In addition, the painting of the gun packs should also match up with the covering of the fuselage. I would like to compliment Top Flite here as I can't think of any other plane that I've ever seen where painted parts matched the covering scheme as well as they did here on the B-25. They definitely did a great job here. When positioning the parts attention needs to be paid to any switches, charging jacks, the air fill valve, and anything else installed on the sides of the plane. I used tape to hold the side guns in place while I traced them.

    With the outline of the side pack guns traced out use a hobby knife to cut the covering away, cutting approximately 1/16" inside of the line that was traced. After cutting the covering away use a paper towel with alcohol on it to remove the traced lines. Go back over the covering with a covering iron to seal down the edges around the cut away area. Use thin CA to glue the side pack guns in place. I found that it helps to glue one part of the gun at a time. I started with the bottom of each pack and then when the CA was dried I would then do the top pack.

    The homework that Top Flite put into this plane really shows in parts as simple as the ADF "Football" antenna mounted on the bottom of the fuselage. This part would be very vulnerable to be broken off while transporting or storing the plane. To prevent this Top Flite has designed this part so that it mounts with strong magnets. This allows the antenna to be removed for transportation or storage, and if the antenna is accidentally "bumped" it will simply come off and can easily be reattached because it's mounted with the magnets. Included in the ply parts is a template for cutting the holes for mounting the magnets in the fuselage. I used a sharpened piece of brass tubing to cut the holes for these magnets. Once the holes are cut use thick CA to mount the magnets in the fuselage.

    Once the magnets are mounted it's very easy to install and remove the ADF "Football" antenna.

    Top Flite has included a very good set of decals to duplicate the paint scheme of the "Executive Sweet", which the plane is based on. While the decals are sticky backed the instructions recommend an alternate way of installing them. They call for using water with a mild detergent for installing the decals, but I prefer to use Windex for this. Spray Windex on the area where the decal will be installed. Cut the decal away from the decal sheet and place it down on the area with the Windex. The Windex will allow the decal to be moved into position without the adhesive on the back of the decal "grabbing" hold. When the decal is in place use a paper towel to push all the Windex out from under the decal. Also use a scrap piece of balsa to burnish the decal into place on the plane. Use the illustrations in the manual, as well as the box art, to indicate where to place all the decals on this plane.


    Balancing the Plane

    The instructions call for the B-25 to be balanced at a point 5" behind the leading edge of the wing, measured at the fuselage side. The instructions also specify to balance the plane with the landing gear in the down position. I must admit that I was a bit worried about the balance of the plane. The plane already weighed over 19 pounds and I was afraid I might need to add more weight to get it to balance properly. Once I had the plane up on the balance stand I was pleasantly surprised, as the plane only needed 2 ounces to come to a perfect level. As you can see in my last picture, I used very "precise" weights to add to the plane! With the plane balanced the final dry weight was 19 pounds 8 ounces.


    Control Throws

    Control Throws:
    Aileron: High Rate: 5/8" Up
    5/8" Down
    (16mm)
    Low Rate: 3/8" Up
    3/8" Down
    (10mm)
    Elevator: High Rate: 1-1/4" Up
    1-1/4" Down
    (32mm)
    Low Rate: 1" Up
    1" Down
    (25mm)
    Rudder: High Rate: 1-1/4" Right
    1-1/4" Left
    (32mm)
    Low Rate: 3/4" Right
    3/4" Left
    (19mm)
    Flaps*: Full Flaps: 1"
    (25m)
    Half Flaps: 1/2"
    (13mm)
    *Note: 1/4" (6m) of down elevator should be mixed in with the full flap deflection to control "pitch-up" when flaps are extended

     

    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot
    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot
    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot
    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot
    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot
    Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot Top Flite  B-25J Mitchell ARF - Photo Shoot

     

    Top Flite  B-25J Mitchell ARF - Flight Report Top Flite  B-25J Mitchell ARF - Flight Report Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report Top Flite  B-25J Mitchell ARF - Flight Report Top Flite  B-25J Mitchell ARF - Flight Report

     
    Getting the TF B-25 ready to fly long before actually getting it to the flying field. Twin-engine planes such as this need absolutely reliable engines, and to get reliable engines requires time on the ground running them. I spent the better part of a day with the plane staked down on my driveway running the engines until I felt comfortable with them. I first started out by breaking the engines in according to the manufacturer's instructions. Past that point I ran them keeping them running rich for another 4 tanks of fuel. At that point I started looking at the low-end settings for each engine. I wanted to make sure that the planes had a reliable low end so I knew they could be powered back up in flight without an engine dying. After warming the engines up I let them idle for 3 minutes and then opened the engines to full throttle. When both engines could be powered up without dying I felt comfortable flying the plane, as I was pretty sure the engines were reliable. All told I used close to 2 gallons of fuel getting the engines to the point that I felt I could trust them in flight.

    I want to make a comment here on the Duralite Flight System battery that was used in this plane. When I talked to Duralite in planning the correct battery for this plane they estimated that I should be able to get approximately 20 flights out of a full charge on the battery. I was a bit skeptical about that until I broke in the engines on this plane. With a full charge on the battery I was able to leave the battery on for 4 hours straight and there was just a little drop in the battery voltage. Think about it, hours worth of flight on one charge. I am definitely sold on these batteries.

    Getting the plane to the field does take a little thought; make sure that a vehicle large enough is available. As you can see in the pictures it takes up the entire bed of my Nissan Frontier truck, but in order to get it to fit I had to take off the rear guns. While transporting the plane I wrapped the wings in a towel to protect them, but I would recommend a set of wing bags for anybody that owns the plane.

    After following the threads here on RCU about this plane I initially was planning on using 12 x 8 3-bladed props for the flights as this was recommended by one of the people at Hobbico that helped develop this plane. But during a conversation with him I decided to change those props out. He suggested using APC 13 x 6 2-bladed props for the first flights of the plane as they have a bit more pulling power and would be better until I learned how the plane flew. Based on his recommendation I used the 2-bladed props for the initial flights of this plane.

    Once at the field I used one of our larger tables to put the plane together and get it ready to fly. While I don't have it in any of the pictures it's a good idea to take the cradle to the field as it's perfect for setting the plane in to check operation of the retracts. Top Flite has done a great job with the B-25 in making it very easy to set up at the field. While the set up goes pretty quick I took my time getting ready as this was the first time with this plane and I wanted to make sure everything was good to fly. The outer wings are installed by first inserting both wing tubes, connecting the flap and aileron extensions, and then sliding the wing in place. The wing is secured with the 4-40 x3/4" socket screw and the 2" nylon bolt inserted through the oil cooler in the front of the wing. I found it important to be careful with installing the nylon screw. I stripped the first two threads off the nylon screw because I didn't have it lined up straight as I started to tighten it down. With both wings installed I pressurized the retracts to 120 psi and tested them to ensure that they were working properly. Next up was a range check on the radio to make sure it was working properly. I then fueled up the plane and fired up each engine to adjust the tuning to make sure each engine was properly set. With both engines set it was time to fire up both engines and taxi out to the runway.

    I'm going to admit that as I taxied out to the runway with the B-25 I was actually pretty nervous about the flight. I was nervous because this was one REALLY nice airplane that I had put a lot of time into getting ready to fly. But I think that just about any pilot is going to be a bit nervous at this point. I taxied down to the end of the runway and turned around and made a high-speed taxi run to get a feel for the way the plane handled on the ground. I did need to adjust the trim on my nose wheel to get the plane to taxi straight. As I taxied back down the runway the plane suddenly pulled to the left. Looking at the plane I found that the left main landing gear was turned to the side, so I shut down the engines to take the plane back to the pits to figure out what was wrong. As I picked up the plane the left landing gear fell out, definitely not good. Back to the table and I found that the setscrews that held the landing gear in were simply loose. I was able to reinstall the landing gear pretty quickly. A quick check showed that the setscrews on the other landing gear were also loose, so I tightened them up as well. This is one where I have to kick myself, as I will admit that I didn't check those setscrews when I was installing the landing gear in the plane. It would be a good idea for anybody assembling this plane to put a drop of threadlock on these setscrews and ensure they are properly tightened down. With the gear reinstalled I topped off the fuel and air tanks and got ready to take it back out. So, back out to the end of the runway and ready to take off and I found another little "problem", although it certainly had nothing to do with the plane. I had set up the timer on my Futaba 9TCAP radio and tied it to an unused switch to start the timer, but unfortunately I had not cancelled out that switch still being tied to the channel that I was using for the left throttle. Because of this when I hit the switch to start the timer it killed the left engine! But that was a quick fix there on the runway that only took a minute or so to take care of. I restarted the engine on the runway and ran both engines back to speed to "blow them out" and get ready to fly.

    I took a deep breath and pushed the throttle forward to get the plane rolling down the runway. Now I have to admit that as soon as I heard that "buzz" that a multi-engine plane makes when the engines are running wide open I felt a little bit better. The plane tracked pretty well down the runway, but I did have a little bit of trouble with the plane bouncing from bumps in the runway but it wasn't bad and easy enough to deal with. As the plane got up to speed it actually lifted up on it's own, which I later found was because the elevator was out of trim. As the plane broke the ground I flipped the switch to retract the landing gear and made the turn in to the pattern we use at our field. Right off the bat I discovered that I was going to need quite a bit of aileron trim as the plane was trying to roll to the left, and quite a bit of elevator as the plane was climbing quite a bit on its own. Because of this I decided to get the plane up to a good safe altitude so that I could trim it out and still have a few "mistakes" to spare. I was able to trim out the ailerons myself with no problems and needed only 4 "clicks" of right aileron to get back to flying level. But the elevator was trying to climb to the point that I had to hold down elevator in to keep it level. Because of this I called for my photographer to give me a hand to add in some down elevator trim. I don't know how many "clicks" it finally took, but it did take quite a bit of down trim to get the plane flying level. I will admit that it was a tense few minutes getting the plane trimmed out. So, with the plane trimmed out and flying "hands free" it was time to bring it down so it wasn't a speck in the sky and see what it could do.

    With the big bomber trimmed and back down to a comfortable flight level I wanted to see how she flew. I brought the plane around and lined up parallel to the runway and ran the length of the runway at full throttle and quickly found that I definitely didn't need full throttle. With it "wide open" the plane was just plain FAST, much faster than was needed to keep the plane flying. As I flew the plane around I discovered that it flew just fine at about 1/2 throttle and was still easy to maneuver. In flight the plane really didn't feel like a war bird but rather more like a sport plane. It turned very well with using the ailerons only, and had no tendency to drop while in an aileron turn. Since we had the camera rolling shooting flight video I made many passes down the runway with the B-25, flying from both directions. I had my radio timer set for an eleven-minute flight and before I knew it the timer was telling me that it was time to land. I have to be perfectly honest that that 11 minutes went by way too fast as I was really having so much fun flying the plane. But I still needed to get a landing in to be able to finish up this flight. As I didn't know how the plane would come in for a landing I lined up with the runway quite a way out from the runway and quickly found out that I didn't need to do that at all. The plane slowed down very easily and I actually had to add power to fly the plane to the runway. Once over the runway I lowered the throttles and let the plane settle down to a very soft landing. I had so much fun on this first flight that if you listen carefully to the flight video you can hear me "whooping it up" as the plane slows down on the runway. Wow, what a fun plane to fly.

    With the trim flight under my belt I wanted to take the plane back up for a second flight to get more of a feel for how she flies. So with her fueled up and ready to go I taxied back out the runway, pointed her into the wind, and opened the engines up. When she reached speed I lifted off the runway. One thing that I noticed right away this flight is that as it's lifted off the runway everything feels just a little bit mushy. But as the landing gear comes up and the gear doors close the plane cleans up and starts flying nicely. The plane is only mushy for a little bit and as long as the pilot is expecting it there is nothing to worry about with it. But once the plane has cleaned up and started flying there are no more issues. At this point the throttles can be pulled back and the plane will respond nicely. My second flight was done pretty much as the first. I did a lot of passes down the runway but this time I did get down to lower altitudes as I became more comfortable with flying it.
    <
    On my first flight I never had to use the rudders for anything other than steering the plane while it's on the ground. So on my second flight I used the rudder to get a good feel for how the plane handled. I found that there was quite a bit of rudder authority and I was able to steer the plane quite easily with the rudders, and coordinated turns were very easy to deal with by using the ailerons in conjunction with the rudder. I brought the plane back in after another very "short" eleven-minute flight and brought it back in to the pits. I honestly had a huge grin on my face.

    My hat is off to Top Flite; they have produced one fantastic flying airplane. At no time in the air did if feel like I was flying an almost twenty pound twin-engine bomber, but rather it felt more like I was flying my favorite sport plane. The plane flies that well.

    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Report
    Top Flite  B-25J Mitchell ARF - Flight Video, Small File
    Top Flite B-25J Mitchell ARF
    Flight Video
    Small File (7.8 MB)
    CLICK HERE
    Top Flite  B-25J Mitchell ARF - Flight Video, Large File
    Top Flite B-25J Mitchell ARF
    Flight Video
    Large File (22.4 MB)
    CLICK HERE
    In years past Top Flite had a reputation of having very high quality kits that produced outstanding planes. And today they produce the same high quality in an ARF plane. The Top Flite B-25J Mitchell ARF is probably the best ARF I have seen, bar none. As the plane is assembled it's easy to tell that Top Flite definitely did their homework as they designed this plane. All structures in the plane are well designed and easy to assemble. The instruction manual is first rate and leaves no doubt as to what is required for each step. A read through the manual before starting assembly will give the modeler a very good idea of what's required to properly assemble the plane.

    One thing that I really think needs to be pointed out is the scale potential for this plane. To start with Top Flite has covered the B-25J with flat MonoKote which really adds to the overall scale appearance of the plane.  Included in the plane are a limited set of parts that will add scale looking details to parts of the plane, but that's not the best part. Top Flite has designed this plane so that modelers have a fantastic platform to start with in adding their own scale features. It almost appears that Top Flite had this in mind when they designed this plane. In fact, several modelers here on RCU have put a great amount of work into adding scale features to their plane. You can find their work here; "Top Flite B-25 ARF (Technical, tips, suggestions)" thread. In addition, several companies are developing scale "add-ons" for this plane. One in particular is WingSpan Models who has developed a working Top Turret and Bomb Bay kit that has the ability to add a working bomb drop mechanism. As this plane becomes more popular I expect that we will see more companies putting out add-ons for this plane.

    One note that I will add here about this plane. When it goes to the field I would recommend others to find some way to block off the front and rear of this plane. I can assure you that this plane is going to draw attention at the field and it would be very easy for somebody to accidentally break off the front or rear machine guns. Because of this I would recommend that owners of this plane find a way to make it so people can not get close enough for this to happen.

    With overall high quality of this plane there are a few items that I felt could have been done better. These items really are minor in comparison to the overall quality of this plane, but I wanted to mention them.

    • The plane includes foam wheels. The included foam wheels just don't look right on this plane. I think that a plane of this quality really should have rubber wheels included with it. In addition, with a plane this size the foam wheels won't last long before they are worn down, especially if the plane is flown off of an asphalt runway.
    • I felt that one portion of the hardware could have been better. I didn't like the use of the #2 x 3/8" button-head Allen screws. Because of the small size I had several of these round out as I installed them in to the various areas they are used. At first I thought this might be caused by the Allen wrench I was using, but I used several different wrenches with the same result. I needed to use different screws to replace those that rounded out.
    • I would have liked to see an identification page included in the manual that can be used to identify all of the hardware in this ARF. There are a lot of nuts, bolts, screws, and such and picking them all out when needed took a little bit of time. A page with sizes of these items would have gone a long way to help identify them all.
    • CA glue used to glue the pieces of the nose canopy together. It might just be me but every time I get CA near a clear canopy there is always at least a spot of CA left on the clear portions of the canopy, no matter how careful I am. I would like to have seen the nose canopy put together in a different fashion than using CA. NOTE: I have heard from Top Flite and they have made a change for future production of this plane which will have the nose canopy parts pre-glued so the end user will not need to do this.
    • The color of the interior scale parts was not correct. Instead of Interior Green and Leather Brown the parts have an almost neon green and a bright orange color. I felt that these parts could have been done better.

    I'm not going to try and kid anybody and tell everybody that this isn't a big project to put together, and it can be a bit on the high side price wise. But I can tell you that all of the work and every penny will be worth it the first time you hear those twin engines as you make a pass over your field. This plane truly is a "Honey" to fly. When you start flying, the plane will be just a bit mushy when you take off, but when the retracts pull up and the gear door close the plane cleans up and starts flying like it was designed to do. This plane flies more like a sport plane than it does a warbird. Top Flite really did a fantastic job and has turned out a plane that is worthy of the title "Class Leading".

    As I wrap up I'll say flat out that I think this is one of the best ARF's I have seen in a long long time. It's well engineered and well put together, and to top it off it's an outstanding flyer. I just absolutely love the way it flies and the way it looks in the air. I don't say that often about a plane, but this one definitely deserves that high praise. This plane had definitely found a home in my hanger. I enjoyed flying it so much that I can't wait to get it back to the field and fly it again!


    Top Flite B-25J Mitchell ARF

     

     

    Distributed Exclusively by:
    Great Planes
    Model Manufacturing Company


    P.O. Box 9021
    Champaign, IL 61826-9021
    www.greatplanes.com

     
     
    Duralite Flight Systems

    D3 PORTABLE ENERGY, INC.
    149 Petworth Drive, Victoria BC V9E 1J4
    Phone: 877-744-3685 Fax 250-744-3696
    www.duraliteflightsystems.com
    Products Used:
    2200 mah - 2 cell Li-MN -7.4 volt, Voltage Regulator, 7.5 amp w/standard 22ga wire 6.0 volt, Load Tester - Digital .5, 1 & 1.5 amp load, Glow Driver
     

     

    Tru Turn Products
    100 West 1st Street
    Deer Park, Texas 77536
    Phone: (281)479-9600
    Website: http://www.truturn.com
    Products Use:TTN-0750-A-140
    3/4 " x 1/4-28 A-Style Prop Nut (2 ea)
    DU-BRO Products, Inc.
    P.O. Box 815
    480 Bonner Rd.
    Wauconda, IL 60084
    Toll-Free: 1-800-848-9411
    Website: http://www.dubro.com
    Products used: Foam Rubber padding
    <APC Propellers
    Landing Products
    1222 Harter Ave.
    Woodland, CA 95776
    Phone: (530)661-0399
    Fax: (530)666-6661
    Website: http://www.apcprop.com
    Micro Fasteners
    24 Cokesbury Rd Suite 2
    Lebanon, NJ 08833
    Phone: (800) 892-6917 or (908) 236-8120
    Fax: (908) 236-8721
    Website: http://www.microfasteners.com
       
    Zap Adhesives
    Frank Tiano Enterprises
    3607 Ventura Drive E.
    Lakeland, Florida 33811
    Phone: (863)607-6611
    Website: http://www.franktiano.com
    Products Used: Thin & Thick CA, 5-minute epoxy, Z-42 Thread Locker
     

     

     

    Comments on RCU Review: Top Flite B-25J Mitchell ARF

    Posted by: Kmot on 06/16/2008
    Thank you soooooooo much for not making another -glow to electric- conversion!
    Posted by: ChuckW on 06/16/2008
    Nothing sounds as nice as twin 4-strokes.
    Posted by: STLPilot on 06/26/2008
    Amazing review! This one must have taken some time. Thanks.
    Posted by: allelectric on 03/25/2009
    Excellent review!!!! But, I am all electric. So, I WISH it had and electric conversion option. It will, I am in the process of building a Top-Flite B-25 and converting it to electrics. I will let everyone no how it turns out. Thanks for the detailed review. It helped make a decision on which large scale B-25 I was going to build and fly. (my Father was a tailgunner in a B-25 Mitchell. Shoot down over Burma. And spent 7 months in a Japanese Prison Camp) Thanks allelectric50
    Posted by: allelectric on 03/25/2009
    Excellent review!!!! But, I am all electric. So, I WISH it had and electric conversion option. It will, I am in the process of building a Top-Flite B-25 and converting it to electrics. I will let everyone no how it turns out. Thanks for the detailed review. It helped make a decision on which large scale B-25 I was going to build and fly. (my Father was a tailgunner in a B-25 Mitchell. Shoot down over Burma. And spent 7 months in a Japanese Prison Camp) Thanks allelectric50
    Posted by: jgarrett on 04/01/2009
    I agree with the first comment, THANK YOU for NOT mentioning electric conversion! I think I might have to have one of these! Thanks, John....
    Posted by: Lifer on 04/15/2010
    What is the span of the main wing with nacelles but without the outer panels? I need to see if it would fit in a mini-van. Thanks!
    Posted by: ledzep443 on 05/20/2012
    I just got this ARF and my inboard flap had similar damage as well! It's not a big deal, I just wish Top Flite would protect that area better on a $600 ARF. Other than that, I am impressed with the detail and quality of the model (until now I have been only a kit builder, but TF doesn't offer the B25 as a kit).
    Posted by: Antoinebobrob on 09/30/2012
    What a nice review and plane! Twin 4 strokes sound great! I am 13 years old and I have an Extra 330.60 that I have been flying for 3 years. The covering is starting to get bad because of all the moisture in our house. Do you have a link where I can get more information on how to shrink the covering?
    Page: 1
    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

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