The World Models
Distributed through: AirBorne Models
4749 - K Bennett Drive
Livermore, CA 94551
Phone: (925) 371-0922 www.airborne-models.com
The Republic P-47 is an aircraft that needs little introduction. Any WWII aviation enthusiast will immediately recognize the P-47 as the 'Jug' or 'Thunderbolt'. It is as iconic as the P-51 Mustang, the F-4U Corsair, and the Spitfire. The latter three played their roles in the war and were well-suited to their jobs, but none protected their most valuable weapon as well as the Thunderbolt. Wrapped in armor and a bullet proof windshield, the Jug was well-designed to bring its pilot home safely. A total of 23 countries have operated the P-47, and it was modified many, many times after its origination.
While not a new release from the World Models, I felt that their 1/7th scale P-47 deserved a proper product review. It's been around for several years already, and many people have already purchased it. I like its size - designed for a 1.20 4-stroke, it makes for an easy gas engine conversion. Nearly any 20-30cc gasser will be a great candidate for installation!
Time to open the box and see what's inside!
Balsa and Ply Construction
Painted Fiberglass Cowl and Air Scoop
Over All Size Good for Transport in Most Vehicles
Pre-installed, Spring Assisted Mechanical Retractible Main Gear
3D cowl Template
Covered in Toughlon Iron-on Covering
All Needed Hardware Included
Air Scoop Required Lots of Trimming to Fit - See Text
Price: $359.99 (Accurate at Time of Review) Stock Number: A213 Wingspan: 70 in (1780 mm) Wing Area: 893 sq in (57.6 sq dm) Weight: 10.7 lb (4.85 kg) Length: 62 in (1580 mm)
Center of Gravity: 4.75 in (120 mm) Back from the wing's leading edge at the wing root Radio Used:Futaba 10CG Engine Used: JC Engines 28cc Evo 2 Gasoline engine (replaced by JC30 evo) Channels Used: 6 total - Aileron, Elevator, Throttle, Rudder, Retracts, and Flaps
The World Models always double-boxes their aircraft, and the P-47 was no exception. Every model I have received from them has arrived in perfect condition! Removing the outer layer gave access to the inside box, which had a large, color label. Along with a nice picture of the Thunderbolt, there were specifications and a required items list. I pulled the lid from the box and found that the top layer had the wing halves, horizontal stabilizer and elevators, and fin and rudder assemblies all individually bagged and taped in place. I do like it when a manufacturer takes so much care to ensure that the product arrives safely! With the top layer removed, I got my first look and the fuselage, cowl, and a large bag of 'goodies'.
One of the first things I noticed about the P-47 is its size - with a 70" wingspan, its small enough to fit in most vehicles, yet large enough to fly on breezy days. This makes it an ideal aircraft for warbird lovers that want to fly nearly every day. The fuselage itself is around 49" in length, and the large main wheels and spring-assisted mechanical gear are pre-installed at the factory!
The bubble canopy is easy to install, though it's a little oversized for a true 'scale' look. The firewall is robust and offers two different mounting options for a 1.20 sized 4-stroke glow engine. One of the neatest features on nearly any World Models aircraft is their inclusion of a transparent cowl template - this makes cowl cutting and mounting MUCH easier, and the paint job on the fiberglass cowl is nearly flawless!
I like that the World Models uses steel, pin-hinged hinges on all of their larger aircraft. These hinges are well made, and I haven't EVER had a single one fail on me! Though the full-scale P-47 did not have split flaps, this one does. The small pocket in the middle of the wing section is there for flap control horn clearance. The tail section of the fuselage has a unique mounting system for the horizontal and vertical stabilizers. I will talk more about that in the assembly section.
In addition to the fiberglass cowl, the Thunderbolt's belly section is also painted fiberglass, and it's removable for disassembly of the plane! The wing has a unique joiner tube, consisting of an aluminum tube with a hardwood dowel inside. There is a taper cut on each side of the tube where it slides inside the wing. One last (but not least) feature to note is that most of this aircraft is constructed of balsa and light ply - other than a few fiberglass pieces, it's all wood, and the fit and finish are top notch!
The assembly manual is very typical for TWM - not many words are used, but there are LOTS of assembly illustrations that do a very nice job of putting the P-47 together. It's probably not a bad idea to look over the manual a couple of times before you begin assembly, though, to familiarize yourself with the different symbols that are used throughout assembly.
Since the main gear are pre-installed, all that was required was to install the gear doors. This was not a difficult task by any means, but it took some time to get them positioned correctly. When I was satisfied with their fit, I drilled holes through the gear door and backing plate and installed them using six machine screws, washers, and nuts. A drop of medium CA was added to each bolt/nut to keep everything in its place.
The holes in all four of the servo hatches were enlarged to allow adequate room for servo arm travel.
The servos were attached to the hatches - I used Power HD 1201MG servos for the flaps and ailerons. They're analog servos with metal gears that produce 169 oz/in of torque. With the servos mounted, it was time to epoxy the wing halves together - I applied a liberal coating of Z-Poxy to both wing roots and the wing tube, slid the two wing halves on to the tube, wiped away the excess epoxy, and used a few pieces of masking tape to hold the wings together until the epoxy cured. Reviewer's Note: The tapered side of the wing tube faces the bottom of the wing.
I attached an 18" servo extension to each of the aileron servos and a 6" extension to each flap servo, and pulled the wire through the wing using the pre-installed pull string, prepared the servo hatch mounts, and installed the hatches.
The pushrods for the ailerons and flaps were assembled and installed next, along with the two retract servos. The retract servos were installed through a hole in the top of each wing, and then covered. The World models included two pieces of white decal material to cover these holes, but I felt they were a little too small. I went to my box of covering materials, found a piece of white iron-on covering, and cut two larger pieces to fit the holes.
A Few Details Prior to Engine Installation
It's not quite time to install the engine, but I thought it was a good time to get the firewall ready. Since the tail hadn't been installed yet, it was much easier to mark and drill the new mounting holes while the fuselage could be set on the floor without damaging the tail feathers. I made a template for my gas engine of choice (in this case, my trusty JC 28 EVO II), and taped it to the firewall. With the four new holes marked, I used the included pieces of dowel to fill the pre-drilled holes closest to my new mounting locations. When the epoxy for the dowels had cured, I drilled the new holes and installed the blind nuts in the back of the firewall.
Tail Feathers, Control Horns, and Pushrod Installation
I temporarily installed the wing, set the horizontal stabilizer in place, and checked for proper fit and placement of the stab to the wing - the alignment was spot on, but I felt a little leery about the thin sections of wood to which the stab would be epoxied. I decided to add some 1/4 " balsa stock to the inside of the stab mounting area, which added more surface area. I now felt better about the horizontal stabilizer mounting, and felt it would not come loose in flight. I mixed up a large batch of 15 minute Z-Poxy, and installed both the Horizontal and vertical stabilizers.
When the epoxy had cured, the tail wheel assembly was secured in place. This was a simple task, and required only a pair of wood screws. The elevator and rudder control horns were installed next, followed by the pushrods and clevises.
Time to mount my engine! When installing a gasser, I prefer to use threaded rod. The threaded rod is screwed into the blind nuts in the firewall, and a nylon locking nut is added inside as well. The light ply spacers were added next, to set the prop hub at the required 152mm from the firewall, followed by the engine's stand-offs, the engine, washers, and four more locking nuts. With that, the basic engine installation was complete.
I had a J'Tec Pitts Muffler on hand for my JC28, but I didn't want to cut large holes in the nicely painted cowl. Instead, I added some short sections of 1/2" copper pipe (regular plumbing copper pipe) and some elbows to make the exhaust exit the cowl in the full-scale location of the exhaust waste gate.
Unfortunately, I found out after a couple of flights that the exhaust was hot enough to melt the solder holding the joints together on my copper tubing. Some high temp silicone and Du-Bro servo screws proved to be much better at holding the copper together!
The fuel tank was assembled using a Du-Bro 'Fill it' fueling system This added a third line to make filling and emptying the tank an easy task. The fuel tank was then slid in place and secured using the large zip tie and double-sided tape included with the P-47. Reviewer's Note: If you plan to use a gas engine with a rear-mounted carburetor, install your throttle cable prior to installing the fuel tank!
Servos and Radio Gear Installation
Time for some more servo work! The plywood servo tray and tri-stock were epoxied in place. When the epoxy had cured, the elevator, rudder, and throttle servos were installed. I used an older JR DS821 servo for the throttle, but otherwise stuck to the Power HD 1201 MGs for the elevator and rudder. A special clamp was used to connect the two elevator pushrods together and attach to the servo with a single rod. I have used this clamp several times, and The World Models has this one right - it ALWAYS works! The rudder and throttle pushrods were connected to their respective servos.
I added a small secondary tray behind the servo tray to install the ignition battery and receiver, and secured the receiver battery to the inside wall of the fuselage next to the fuel tank. Since I installed a gas engine, I made certain that there was plenty of Du-Bro dense foam protecting my on-board gear.
Scale Details, Canopy, and Cowl Installation
There are several extra painted plastic pieces that need to be installed. I cut and removed the covering on each side of the fuselage, epoxied the intercooler air exits into the holes, and taped them in place until the epoxy had cured.
The supercharger exit was next on the task list. I marked its position, removed the covering 1/16 " inside the marked line, and epoxied the exit in place. The fiberglass wing cover/air scoop was locked in place using two latches. Reviewer's Note: The wing cover MUST be trimmed to fit the wing. If it doesn't latch easily in place, it will put undue stress on the latches, causing failure.
I attached the canopy using four silicone washers and screws. I chose not to install the included pilot at this time. The six cowl mounting lugs were screwed to the marked locations on the fuselage, and the cowl was mounted using the six plastic rivets and screws.
Cowl Fitting and Oil Cooler Istallation
To create an air gap around the custom exhaust pipes, I removed a small portion of the cowl and applied a small piece of aluminum foil tape. The foil tape was applied to keep excess heat away from the covering. The two plastic oil cooler were secured using the same method as the supercharger exit, and the decals were cut from their sheets and applied.
At this point, the P-47 was so close to complete, but I was waiting for a couple of items to arrive. I purchased a 1.5" Tru-Turn prop hub, and my friend, Steve Thomas of Bob's Hobby Center, had sent me a Falcon 18x10 beechwood propeller. When they arrived, I installed them and checked the Center of Gravity. The CG came out perfectly - and that meant it was time to go flying!
Falcon Propellers and Bob's Hobby Center at Steve's Hangar
Bob's Hobby Center at Steve's Hangar is the US distributor for Falcon Propellers. They offer a full product range - i.e. gas wood props,electric wood props, carbon spinners for gas and electric applications, and carbon fiber props for both gas and electric. At the 2014 Extreme Flight Challenge, 13 out of the 15 competitors flew Falcon Props!
As well as being the US distributor for Falcon and Xoar, Bob's Hobby Center is a great, full-line hobby store with knowledgeable, helpful employees. If you're in Orlando, Florida, stop in at Bob's - you'll be glad you did! You can also find Bob's Hobby Center on the web. If you're looking for a full line of high quality propellers, look no further than FALCON PROPS!
About a week after completing the P-47, we got a break in the weather. I loaded the Thunderbolt into my small SUV, and headed to the field! It was a nice July evening - the temp was pushing 80 degrees, and the wind was fairly steady at about 10 MPH.
The pilot I had ordered arrived the day before the maiden, so I got 'him' secured in place. While The World Models does include a pilot with their planes, I felt the included pilot was a little too 'cartoonish' for a beautiful looking model. The replacement was purchased on e-bay from Pete's Pilots - they're hand painted in Stafforshire, England. I had the pilot a week after I purchased 'him'. Not too shabby for a flight 'across the pond'...
As I do with any maiden flight, I performed a range check on the radio gear. With that completed satisfactorily, it was time to fuel up the JC 28 and get the Thunderbolt in the air. A few flips of the Falcon 18x10 prop brought the engine to life, and it looked very realistic with a few 'puffs' of smoke coming from the exhaust. I taxied the P-47 out on to the runway, and was very pleased with the robust main gear and steerable tail wheel.
With a final check of the control surfaces, the throttle was advanced, and the Thunderbolt was rolling down the runway! The take-off roll was approximately 60 feet at three-quarter throttle, and the P-47 lifted off and started climbing out. Even at three-quarter throttle, the JC28 was easily pulling the airframe.
I pulled up the gear shortly after the initial turn , and a quick circuit of the field had the P-47 trimmed for straight and level flight - four clicks of right aileron and six clicks of down elevator were needed to fly 'hands off' at half-throttle. Another circuit later and I put the Thunderbolt through its first aileron roll. I had set the aileron deflection according to the manual, but it felt a little 'heavy' while rolling. But it was the maiden flight, so I figured I'd push on and see what else the plane would do.
At full throttle, the JC28 was turning about 6000 RPM with the Falcon 18x10 prop, and that gave the plane a nice sound - not so high pitched as to sound whiny, and the P-47 flew very quickly!
I pulled the throttle back to about one-third, and dropped the flaps one notch to the recommended 35mm. The nose pitched up slightly until some speed was bled off, but then settled in nicely and flew well at slower speeds. I shot a couple of 'practice landings' about 50 feet in the air with the flaps down, and the P-47 reacted just as I suspected it would - Nice and easy, with just a touch of power held on.
I decided to bring the Thunderbolt in for a landing and adjust the aileron deflection. Just as my practice landings went, so did the actual landing. With the flaps dropped, the P-47 settled in nicely with about one-third throttle, and I cut the power to nearly nothing as I crossed over the mowed section of our field. The Thunderbolt gave one small hop, then settled back down on the main gear and dropped the tail a couple of seconds later. Unfortunately, the grass was a little tall on that evening, and the P-47 nearly nosed over when it rolled off the end of our textile runway. But, quick thinking on the elevator saved the Thunderbolt from a rough landing. I would recommend adding 50% more throw to the elevator with exponential if you plan to fly from a thick grass runway - this will give the additional authority to keep the tail down after landing, yet retain smooth flying characteristics in the air.
With the ailerons deflection adjusted, I put the plane back in the air and tried some aerobatics. A full-throttle take off was about 20 feet shorter, but looked a little more 'sport plane' like. At altitude, I rolled the P-47, again, and was immediately happy with the extra aileron! The Thunderbolt no longer felt heavy - it felt RIGHT! The JC28 had more than enough power to pull the plane through ridiculously large loops, and stall turns and split 'S's' were a breeze. The P-47 tracked through all maneuvers easily!
Check out the video to see her in action!
The World Models 1/7 Scale P-47 ARF
Time to wrap this one up. The World Models has produced a lot of really nice airplanes over the years, and the 1/7 th scale P-47 is no exception. Though the canopy is too large for that true 'scale' look, it certainly isn't a deal breaker. The P-47 looks good, flies better, and will definitely be a great addition to anyone's hangar. I am really diggin' my Thunderbolt, and plan to have it around for several years to come!
Distributed through AirBorne Models
4749 - K Bennett Drive
Livermore, CA 94551
Phone: (925) 371-0922 www.airborne-models.com
Distributed through Hobbico
2904 Research Rd
Champaign, IL 61822
Phone: 1-217-398-8970 www.futaba-rc.com
Distributed through Bob's Hobby Center
540 N Goldenrod Rd
Orlando, FL 32807
Phone: (407) 277-1248 www.bobshobbycenter.com
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.