The twin ducted fan jet on the right is designed by Super Flying Model and sold in the U.S. by Hobby Lobby International. It is made from molded-bead foam construction, has a 47" wingspan, and meant to fly at around 47 oz. or 3lbs. The model resembles a Learjet 45XR with the lower dart fins on the tail. The larger engine pods are typical on an EDF powered R/C model.

The fuselage comes with two 66mm ducted fans that are pre-installed and ready to mount the motors. The wings are reinforced with carbon tubes and have molded recesses for the aileron servos. The wing tips are made of wood and come pre-covered. The bottom of the wings have molded pockets with plywood mounting blocks for the included fixed landing gear or you can upgrade to the optional retract gear set (SFM3501B) with steerable nose wheel.

The Exec Jet assembly was quite easy since there were very few parts in the kit. I added the optional retracts to my model which also require several more servos.

All the bays were ready to accept servos and retracts but the fuselage bottom needed to be cut for the nose wheel. A template is provided for tracing the right cut outline.

The ailerons, elevator and rudder are made of balsa and covered with heat-shrink film. They are pre-installed and the hinges are pre-pinned for safety. The fuselage has wooden servo mounts and battery tray pre-installed. The model is powered by two 3s 2100mAh packs.

My power system was upgraded from the stock 3-blade rotors to the well balanced Wemotec 504 rotors while still using the stock pre-mounted fan units. Ductedfans.com sells a nice Dual Rotor Upgrade Kit (WE504ex2) for this purpose. The Wemotec rotors and adapters allowed me to use the 3.2mm shaft AMMO 28-35-3900 Brushless Inrunner motors to double my power level over the stock 2.3mm shaft SFM Outrunner motors.

My Executive Jet was ready for taxi testing in a nearby parking lot. The March weather was sunny but still cold and the flying soggy flying fields would not be open for another month or so. We were just happy to see the snow was gone.

The SFM Exec Jet taxi testing went very well. I did find that one of the retracts was not properly locking down but that was fixed with a simple servo travel adjustment on the transmitter. In a future issue of AMP'D, I'll show some flying photos and a video with both a hand-launch and pavement take-off from this summer.

The newer "Version 2" Hero 100 Twin EDF Executive Jet from Nitro Planes is a larger 71" span semi-scale Cessna Citation II fiberglass model aircraft. This twin-EDF model was designed around dual 101mm fan units and matched D36-2200kv brushless motors. Created for the advanced sport scale pilot, the Hero Eagle 100 ARF is designed for easy assembly and setup using quality wood construction with a fiberglass fuselage.

The removable front hatch also allows for easy access to the radio equipment and batteries. The entire trim scheme is pre-painted, and the the wings are covered in quality shrink material. Most of the decals have already been applied and all hardware and accessories are included.

Specifications:

• Wing span: 71 in / 1803 mm
• Wing area: 746 sq in / 48.4 sq dm
• Flying weight: 14.3lb / 6500g
• Fuselage length: 71 in / 1803 mm
• EDF : 101mm / 4.0 in x 2pcs
• Radio Required: 6-channels, 8-servos
• Brushless Motors : D36 x L 50 mm , 2200 kv
• Speed Controllers : 22.2 v ; 85A
• Li-poly Battery : 4000mAh ; 25C

The Hero 100 Cessna 550 comes in a big 68" long box. The plane looked well packed and the parts were either wrapped in foam or plastic.

I split the box photos in half to get a closer look. The fuselage spans the entire length of the box.

The wing halves measured 31.5" each. All the wood surfaces were perfectly covered without a single wrinkle. This was unexpected quality from a $200 ARF of this size.

The control surfaces, like ailerons, rudder, and elevator halves, all had the hinge material inserted but needed to be glued with thin CA.

The main wing tube measured 27.5" across. I discovered another addition to the Version 2 kit, there were three wheel retract bays instead of two on the original kit.

The kit came with a decal sheet and a 10-page glossy manual with clear photos. The decal sheet includes both scale decals (that I plan to use) and non-scale decals for the model name.

The manual appeared to be for Version 1 and shows using a steerable non-retractable nose wheel. This option, along with the wheels, still comes with Version 2 for those that don't build it with retracts. There is no cutout on the bottom of the fuselage in the manual and the canopy section has been crossed out with pen marks.

Overall, I think what you get for only $200 is a great value and I was excited to finally start this project after a 6 month wait for it to return to stock. There are certain pitfalls with these lower cost fiberglass models from China but they can easily be overcome with some experience and skill. I will address these issues along the way.

The large one-piece fuselage was 68" long. Most of the colors and decals had already been applied. I decided that I would be modifying the color scheme to closer match the full-scale Cessna Citation that this design mostly mimics. More to come on the scale-up process.

The formers, retract bays, and servo/battery bay appeared to be intact but I recommend doing a full inspection for strength of adhesion to the fiberglass body. I typically use the aerospace grade epoxy called Vpoxy from BVM Jets to ensure a quality bond between fiberglass and other materials like wood or plastic.

Note the addition of the nose wheel retract cutout and retract bay in the Version 2 kits.

There was an odd 90 degree twist in the cutout and matching well. Since my plan was to use Spring Air 301 retracts with Robart struts, I needed to make some changes.

The Hero Eagle 100 was modeled after the full-scale Cessna 550 Citation II research aircraft from NLR in the Netherlands. The Cessna Citation II PH-LAB is one of the research aircraft operated by the National Aerospace Laboratory NLR. It is owned and operated jointly with the Delft University of Technology, Faculty of Aerospace Engineering. Originally designed for executive travel, this Citation II has been extensively modified by NLR and Delft University of Technology to serve as a versatile airborne research platform.

The full-scale Citation II is a twinjet aircraft of conventional aluminum construction. It can accommodate up to eight passengers (or observers) in addition to the two-pilot cockpit crew. The plane's registration, PH-LAB, is derived from the Netherlands designation of PH (like N for USA) and the three letter call sign LAB for Laboratory. The flying laboratory's primary purpose is to teach students what it takes to do measurements on dynamic flights, sometimes in zero-G conditions, and as a platform for atmospheric measurements all over the world.

The non-scale colors of the Nitro Planes' Hero 100 appear to be from combining schemes of several Cessna Citations together. The yellow appears to be derived from the international Aeromed Medivac Cessna Citation II; N174DR.

Other colors like the bright red across the leading edges were likely chosen to increase orientation in the air. I'll be changing some of the shrink film colors on my wing and tail as well as removing the yellow from the fuselage.

My navigation lights for the Cessna 550 are the EDR-117 LiteSys from Electro Dynamics. This plug and play lighting system for scale models uses the ED-SunVis Wide-angle lamps that are visible in sunlight. The dual RC Switch can either turn the lights on whenever the receiver hears the transmitter or by a spare channel. I'm using the LiteSys Starter System with Transmitter-controlled switching for $119. It includes the following items.

• Red and Green Nav Lights
• Red Beacon or White Strobe (select)
• 4-way Distributor
• Landing Light
• Dual RC Switch

My retract choice is the Spring Air 301 Firewall Retract Set. These retracts use air pressure to go up and spring force to go down. I have successfully used this brand in the past on my Byron A-4 Skyhawk and feel they offer a good quality value with a great fail-safe mode of operation. If you loose the air pressure, the retracts lock down in the landing position. Carl Rich also proved that these retracts were a good size choice on the Version 1 Cessna. The 301 retracts can handle models up to 15-16lbs.

Instead of using the supplied wire mains, I'm using a pre-enjoyed set of Robart 501 struts with Dubro (275TL) 2-3/4" Treaded Lightweight Wheels.

Any strut can be easily added by making your own 5/32" pin with a Dremel tool. The struts not only reduce bounce on landing but enhance the gear appearance by eliminating the skinny wire look.

My power system components will be the following items...times two.

• Neu 1415/1.5Y inrunner motor
• Castle Creations ICE 100 ESC
• RC Lander 90mm DF
• Two 4s 30C 4000mAh Blue Lipo packs in series
  

My original plan was to use Wemotec Midi Pro fans. When I received the new RC Lander 90mm metal DFs, I was very surprised at the quality of the machining. Further, it fit perfectly into the Hero 100 nacelle and was a great color match! I didn't have any measurements on the fan performance so I needed a way to compare it with the Midi Pro rotor. RC Lander also makes clam shell mounts for these 90mm DFs so it will easily mount onto the platform in the nacelle.

The RC Lander rotor is only 5-blades compared to the Midi Pro 6-blade rotor but it does have a more aggressive pitch so perhaps the loading and thrust may be comparable. The rotor is made from some composite that is very hard and the quality was very high so that I did not see any flaws.

I made the following weight measurements.

• 2-piece fan housing = 3.1oz
• Rotor, spinner, and adapter = 1.4oz
• Red tail cone = 1.6oz

Here are some photos of the RC Lander 90mm DF using the Wemotec Midi Pro rotor and spinner. The 6-blade Midi Pro rotor is on the left and then mounted in the fan. The shaft size and adapter screw are the same so it fits right on the Lander adapter. The Midi Pro rotor length is slightly smaller than the Lander rotor length by about 4mm.

It looked promising for a reasonable load on 8s LiPo with the Neu motor. If not, then the Midi Pros will provide a known 2500 watts per side with great efficiency.

I measured the distance needed from the nacelle to the ESC (mounted in the fuselage) and extended the motor wires by 6" of #10 Castle Creations wire. This would also allow me to mount the assembled nacelle first and then connect the motor wires to the ICE 100 ESC via the bottom hatch opening in the fuselage.

My new ICE 100 ESCs had built-in data logging so I could easily take my power, current, and RPM measurements while measuring the thrust on my new low-cost thrust stand, shown below. The 6mm gold bullet connectors on my LiPo packs could now plug directly into the ICE 100 ESC without the need for an external in-line wattmeter, which can sometimes damage ESCs due to the added inductance. For more information on this incredibly useful feature from Castle Creations, go here.

The Castle Creations Data Log showed that I was right on target with a full throttle reading of 90amps and 2400 watts. The 37.1K rpms proved that the Neu 1415/1.5Y inrunner motor is really spinning that 90mm rotor! I changed the PWM setting from the default of "Outrunner" to 12KHz as a middle of the road setting that should not make the controller too hot. The little blips on the charts before the full throttle tests were from me giving a small throttle movement to check the system after the Spektrum receiver sync lights came on.

For only $14 at Harbor Freight and another $19 at Gander Mountain Sporting Goods, I created a $33 thrust stand with some additional scrap plywood. The Rapala Digital Fish Scale can read up to 50lbs or 25kg without any movement of the chain. I simply removed the casters and reversed the long planks so that the flat side faced the inside. The drawer slides were mounted with the supplied screws and then held with a custom base meant to hold a 90mm EDF. I initially secured the Rapala scale with large wood screws to make my measurements but I will likely make it removable in the future so that I can also use it to measure the installed system in the plane.

At full throttle, my scale read about 6.5lbs static thrust. Although this may not be too accurate without a thrust tube in place, it was a good sanity check that allowed me to move forward with the RC Lander DF and rotor.

The first step of assembly in these larger low-cost fiberglass models is always inspection. While I was surprised at the wrinkle-free covering, I was not surprised to find some loose formers.

It is always best to take some time at the beginning of a project like this to stress test all the parts that come in contact with the fiberglass. Even if you do not find loose formers, I still recommend running a bead of a quality epoxy like the VPOXY from BVM Jets. Another popular brand is the Locktite Hysol.

To fix loose areas, the proper procedure is to first tack glue the area with medium CA, let it dry, and then run a bead of VPOXY preferably on both sides, although this is not always possible. There are different length mixing tubes available for the gun or you can mix it yourself before applying it to the surfaces.

The next step of the assembly is to complete the wings. The Spring Air 301 retract installed easily after first making some minor cut adjustments. I also noticed that with a little modification, you could mount the flap and aileron servos sideways for a cleaner look. I used JR DS821 digital servos because they offer strong torque and great return to center for a reasonable price.

The flap servo mounted sideways after a few cuts with a Dremel tool and a small block of balsa underneath to raise it up flush with the surface. The aileron servo needed a tray running between the two ribs. I used a scrap piece of light plywood. To extend the servo wires, I used JR (JRPA102) 24" Heavy Duty Servo Extensions.

The plug and play navigation light easily mounted on the wing tip after drilling a hole from the end into the long open bay that travels the length of the wing.

By drilling a hole from the wheel well into the main bay that runs the length of the wing, all four lines could exit the normal opening that goes into the fuselage without further modification.

When I looked at the supplied hardware, I knew that I wanted to mount the control horns on the bottom side only for a cleaner look on the top of the wing. The control surfaces were plenty thick so I used the supplied wood screws instead of the intended machine screws that were meant to pass through the control surface. By pre-drilling some pilot holes for the control horns and using some CA, it created a strong hold that could not be seen from the top. I didn't think there was a long enough block in the flap for the outer most screw so I cut an opening in the covering and added a small piece of plywood.

One issue I had with the hardware was that the threaded ends of the aileron and flap control rods were too small for the plastic clevis. I used my own metric control rods from an old bulk pack (HLH804) I bought from Hobby Lobby years ago. Since these control rods also came with a metal clevis, I used those instead of the supplied plastic clevis.

All that remains to do on the wing is to cover the red and yellow sections. This will be saved towards the end of the project.

The yellow on the fuselage was re-painted with Valspar Gloss White (102S) Spray Enamel paint. First, the black lines were masked off and then the yellow area was sanded with #220 grit sandpaper. I then taped paper towels over the rest of the fuselage before spraying. Several coats of paint were needed.

A burgundy (maroon) color line will be painted in the center between the two black lines. The color will be close to the burgundy covering used to eliminate the remaining yellow on the control surfaces.

Before mounting the Lander DF unit in the nacelle, I added an MPI (ACC3939) Heatsink for 36mm motors. These low-cost heatsinks simply press into place and keep your motor cooler which helps add longevity. Also before mounting the DF, I added extra epoxy to the mounts in the nacelle.

I discovered that there was a thrust offset in the nacelle motor mount that made the DF point away from the fuselage. I centered the thrust line by using some washers in the aft end of my Lander clam-shell mount and slightly recessing the front end with a Dremel tool.

The nacelle cover was temporarily taped into place. The fit was not great so it will require some cutting with the Dremel tool before being finished. I'll also be adding some exhaust tubing for an 85% FSA. With a setup of 2400 watts per nacelle, I can sacrifice some thrust for added speed.

After finishing the second wing, I was able to install them on the fuselage using the two aluminum tubes. The larger diameter and longer tube needed to be cut shorter about an inch before the wings would butt up against the fuselage. The fit seemed pretty good so I secured the wings to the fuselage using the supplied bolts and wooden washers.

I used a piece of foam to position the nose at the proper angle. This length can be used to check the nose wheel distance from the fuselage when installing the retract.

Note that I used a reverse DS-821 digital servo on the second flap in order to utilize a single channel by using a Y-harness. The second aileron still used a standard DS-821 servo since it needs to move in the opposite direction. Both flaps use a single channel and both ailerons use a single channel.

For the nose retract, I wasn't quite sure what the manufacturer had in mind. Not only was it intended for a 90 degree rotating retract but it was also cut off center. The pre-installed 4mm t-nuts did not match the footprint of my SpringAir 301 retract so it was time for some changes.

I decided to use one of my articulated-knee Spring-Shock struts from Golden Skies R/C. For only $27 each, this well-made strut can handle models up to 16lbs.

After first cutting the bridge away on the second former, I re-located the 4mm t-nuts for the SpringAir retract and corrected the center line. I used my foam piece from the previous step to help determine how long my 5/32" music wire pin needed to be. Both the Spring Air 301 retract and the Golden Skies R/C strut are made to accept the 5/32" wire.

In order for the wheel to retract into the fuselage, I opened the bottom up a bit using a Dremel tool.

I finished up the nose retract installation by adding three pieces of plywood for additional strength. Two square pieces bridge the two formers and a third triangle piece runs from the first former forward. The whole assembly was now very solid.

My steering retract was a Futaba S3115 mini servo. The metal linkage was short, easy to adjust, and wobble-free. It is important to keep the white swivel horn on the SpringAir retract in line with the retract joint so that the wheel does not turn as it retracts.

I used a mix on a spare channel to the rudder in my Spektrum 9503 transmitter. The same mix also disables itself when the gear switch is in the retracted position so that rudder movement does not turn the nose wheel during normal flight.

Notes: The nose retract, servo, and linkage are not part of the Cessna kit. The epoxy I have been using is 3M Scotch-Weld DP-110. I had several tubes on hand so I decided to use it up. It has a 9-minute worklife and is similar to V-poxy and Hysol but has a yellowish color instead of white or clear.

The next step in the assembly was to mount the stabilizers so it was time "to get the red out". I covered the cherry red sections of the stabilizers with maroon Monokote and used 3M Scotchcal Striping Tape to blend in the joints. The burgundy colored striping tape comes in 3/32" and 3/16" widths and is available at most automotive detailing stores.

The re-painted yellow stripe on the fuselage was also detailed with the burgundy Scotchcal tape.

While the horizontal stabilizer fit well on the fuselage, the vertical stab wasn't even close. Further, you can see that the rudder covering does not match the vertical stabilizer...suggesting that kit parts from Version 1 and 2 may have been mixed. It didn't take much effort to make it work. As long as you expect some issues on these low-cost fiberglass ARFs, you are prepared to make adjustments. I also enjoy making small enhancements along the way.

The elevator servos were installed in their normal positions but since the nose wheel retracted into the rudder servo position, I re-positioned it further back and down by the fuselage. I made some servo holder blocks from one of the unused stock gear mains mounting blocks. Note that one of the elevator servos is a reverse servo so that only a single channel is need for elevator control.

The three long control rods had the same fit issue as before when using the supplied clevis. I took one to my local hobby shop and they measured the threads as 2mm with a .4mm pitch. This meant that I could use some Dubro 2mm hardware.

I purchased some #819 Dubro 2mm Safety-Lock Kwik-Links for my tail connections.These Kwik-Links worked perfectly with the rest of the stock hardware.

My installation technique was to keep the control horns on the bottom side which made for a clean look from the top side of the Cessna. I used some medium CA into pre-drilled pilot holes and mounted the stock control horns using the supplied wood screws that are just the right length to not push through to the other side of the control surface.

The plastic control rod sleeves were epoxied in place and then painted.

I mounted the right nacelle using the supplied M4 screws and t-nuts. My kit had no Mylar for the thrust tubes so I picked up some .020" thick Duralar at a local art supply store. I knew the nacelle exit would be large for my 90mm power system so I wanted a thick tube that could stand on its own without any support. The Cessna application is not all that weight critical.

I borrowed the thrust tube photo from my Nitro Predator UCAV project and changed just the length dimension to 9.25". Since both applications used 90mm EDFs, the ends of the tube are the same for the desired 86% FSA. I usually cut the tube a little longer and then trim it to where I want it later.

The nacelle cover wasn't a perfect fit but it wasn't bad for this low-cost ARF.

The Castle Creations ICE 100 ESCs fit nicely on the bottom of the fuselage. By cutting the right size rectangle in the fiberglass, you can pop the ESC into place using the built-in heat sink as a holder. The ESCs protrude just slightly so they can get some cooling air during flight.

I mounted the second nacelle like the first. The covers didn't fit all that well and made me wonder if they were original version 1 parts on version 2 nacelles. Since the new plastic canopy fits great on the fuselage, I would have preferred some better fitting plastic nacelle covers instead of the ill-fitting fiberglass ones. The nacelles fit great against the fuselage and I saw no thrust offset.

To support all my digital servos and navigation lights, I decided to use the new CC BEC Pro from Castle Creations. It provides 10-amps continuous current and 20-amps peak on a wide range of supplies from 3s to 12s Lipo. Further, it can be programmed from 4.8v to 12.5v using the CastleLink software and only weighs an ounce. It allowed me to use any of my smaller 3s LiPo packs, around 1AH, as a receiver pack.

The CC BEC Pro fit nicely under the battery tray and connects to my 3s Lipo pack without using a switch. It has two output lines going to servo connectors that can handle up to 5-amps each. This was a perfect mate to my JR R921 9-channel 2.4GHz. receiver that has two battery inputs for redundancy.

I also mounted my EDR-117 LiteSys controller next to my receiver as it was time to mount the strobe light and the gear light. Note that the wires have increased in quantity. I plan to clean them up after my initial checkout of the control surfaces and lighting.

The two 4s Blue Lipo 4AH packs seemed to fit well in the area provided. In addition to Velcro on the bottom, I used a wide Velcro One-Wrap strap as a safety belt. This strap also helped secure the wires underneath the tray.

The white strobe light was too difficult to mount on top of the vertical stab so I positioned it on top of the fuselage. The very bright flashing strobe can be seen from any direction around the plane. I'll likely save mounting the last white nose gear light until after my taxi testing.

The plastic canopy was cut out from the mold to fit well on the fuselage. I then epoxied a dowel and block to the canopy front and drilled a mating hole into the fuselage. By using dual hatch latches, one on each side, it held the canopy in place fairly well. The latches were secured with Plasti-Zap after first sanding the contact surfaces.

I found the white hatch latches for sale on the RCU Marketplace for $6 each. Hobby Lobby also sells the HLRE001 for $5 each.

To increase the hold so that the front ends would not flap in the air stream, I created a balsa frame for the front of the canopy. This technique allowed the canopy to be easily removed while keeping it secure during flight.

The bottom hatch opening wasn't quite square so I needed to trim some of the corners on the cover before it would properly screw into place.

Since this photo was taken, I marked the CG location on the fuselage bottom at 106mm back from the leading edge. This was 31mm forward of the suggested CG in the manual but proven to be a better choice by Carl Rich.

It was time to focus on changing the color scheme and adding some decals.

The stock yellow and red colors were replaced with burgundy and flat black vinyl covering that was purchased from a sign shop. The sticky-back covering was easier to apply without wrinkles than the initial Monokote shrink film I used on the tail.

Since there are several versions of full scale PH-LAB Cessna, I choose to mimic one that allowed me to use most of the supplied decals. By first cutting away the clear sections with a razor knife, the decals apply much easier without wrinkles or bubbles.

I had the "Delft University of Technology" decals made special by RCU's Matt Kirsch.

The initial taxi test on pavement went very well. Although I never went above 1/3 throttle, the Cessna Citation seemed ready to go. All the control surfaces worked smoothly and I powered up each 8s system using my anti-spark 100ohm resistor that had proven successful in several previous projects.

The now majestic looking Cessna Citation II taxied without effort on pavement. My plan is to fly it off a grass field so we will see how much runway is needed when the 4800 watt power system is a full throttle.

All that remains is to create the air retract control board and cut the thrust tubes shorter. I will likely add a few more scale details as this is a very fun part of our hobby!