FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I recently purchased another Fly Eagle Jet aircraft. The first FEJ was one of the original 1:6.5 A-10 that was built and flown as an AMA LTMA jet last year. This time I purchased a FEJ 1:6 scale J-10 'Vigorous Dragon'. The one I purchased is not the 3D model, but is also constructed of the light weight honeycomb material. It has an operating canopy, full cockpit, airbrakes (4), and scale landing gear / doors (unlike the 3D version).

I did not document the building of the A-10, but I thought I would do so for the J-10. I intend to show all the great things related to the build, as well as, areas for improvement. Please be patient since I am a relatively slow builder and tend to jump around to various locations on the jet during building….

I resisted temporarily assembling the J-10 for pictures, but have included the factory pictures of the jet just after it was painted. The paint job of the J-10, as received, was outstanding.

Nick

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I weighed each major grouping of components before assembly:

Wings = 2 lbs 5 oz. each
Forward Fuse, cockpit, and canards = 5 lbs 10 oz.
Rear Fuse, Rudder / Fin = 10 lbs 2 oz.
Pipe, bellmouth and fuel tank = 1 lbs 10 oz.
Misc parts supplied (aluminum servo brackets, pushrods, etc.) 4 oz.
Total weight as delivered by FEJ = 22 lbs 4 oz.

I am using Hitec 7955TG servos on all main control surfaces (same as A-10). Also, using Smartfly PowerExpander Competition 12 with a Futaba 6014FS receiver with 2 switches and two 2300mAh A123 2S batteries (my normal jet setup). Working with Dan Gill (Details4Scale) to make up a lighting package for the 1:6 J-10.

The cockpit is made from very thin styrene plastic. Plus side, it is very lightweight; but not the same quality as I received for my FEJ A-10 or other manufacturer’s cockpits. I decided to purchase a toy 1/6 scale “helicopter pilot” in a red flight suit from Amazon – very inexpensive.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

The fuel tank supplied is a single 120oz. fiberglass tank (no internal baffle; I did replumb the tank though). It mounts ahead of the CG. I may be adding an additional 'custom' fuel tank and smoke tank in the future (only place to put them is directly in front of the main tank). As you can see I had to enlarge the one bulkhead to allow the fuel tank to be mounted as per the instructions. I also mounted the new Dreamworksrc overflow vents (one for fuel and one for smoke).

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I decided to tackle the canards first. If you look at the FEJ 1:6 J-10 “instructions” online, you will see long special aluminum servo brackets supplied to mount the servo to the bulkhead where the canards mount (pic 1 and 2). I did not receive those; I received the normal aluminum mounts for the servo boxes for the canard servo. I did look at the 1:4.85 size J-10 instructions and they show the normal aluminum mounts being used (pic 3). One hurdle though, in both size instructions, the aluminum canard arm is configured / machined differently than the one supplied to me (pic 4 is mine and notice where the screws are located.) You cannot mount my aluminum canard arm with the arm facing down, with the servo mounted to the “cross tray”, and still tighten the aluminum canard arm screws and set screws. So, I flipped the aluminum canard arm up and had to place a block of wood on the cross tray to raise the servo to the correct height. Now I can tighten all of the screws on the aluminum canard arm. I did file a flat where the set screws contact the aluminum canard arm and also used a Robart incidence meter to ensure both canards were set correctly.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I decided to tackle adding the steering servo to the scale nose gear. The scale nose gear is a work of art! I couldn’t see a way to mount the steering linkage without removing the nose gear from the fuse, but it did afford me a chance to see how the gear was mounted to the fuse. As you can see, the nose gear frame is mounted to the rear with two screws into a honeycomb partial bulkhead with some carbon fiber to reinforce the area. The front of the frame uses 4 wood screws into a piece of plywood which is glued two honeycomb partial bulkheads. I had to remove some of the rear bulkhead on one side (in red on the pic) so the steering servo could be mounted. A little difficult mounting the servo since the gear frame must be inside the fuse when you attach the servo. Also, you must purchase a button head screw for the front top location, otherwise the screw head will hit the strut when retracting. On the 1:4.85 scale J-10 instructions, you can see some carbon fiber cloth covering / strengthening the ply and a portion of the inlet duct. This was not done on the 1:6 scale.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I find myself liking this model more and more as I look at it. I think it will be one of my next after the A-10 I ordered. looks great.

Kevin

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

The first task to mount the exhaust pipe and turbine is to install the fiberglass exhaust nozzle to the rear fuse to locate the rear of the dual wall pipe. Once the fiberglass exhaust nozzle is in place you can see where the pipe straps need to attach to the turbine mount rails in the rear. I did cut a relief in both sides of the bellmouth to allow the straps to line up with the turbine mount rails.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

After the exhaust pipe was installed I could then locate and line up the turbine for installation. I needed to cut small reliefs in the turbine mounting rails to allow the KingTech K-170F mounting bracket to clear the rail. I used 6-32 socket head cap screws and blind nuts in the rail. I then located and mounted the partial bypasses to keep debris from coming up through the huge main gear door openings. I will be painting a portion of the rear 'bypass' and the fuse near the bellmouth with BVM HeatShield” later in the assembly.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

I then attached the rear strakes with Hysol after determining their location from looking at scale pictures of the J-10. You must be careful locating these strakes since if they are mounted too far forward they will interfere with the wing inner elevons.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Created a plate to mount in the hatch opening just aft of the fuel tank. It contains air fill valves and air gauges for Gear and brakes, fuel fill valve and manual fuel shutoff, and connector for the turbine GSU.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

THe detail they have added to the china plane is nice, guess they take some pride in their countries model :D

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Next, I built a cradle to hold the Hansen UAT. It is going to be mounted under the main tank between the main gear. I decided the best place for the fuel pump and valves was under the forward end of the main tank. The v10.x ECU is nearby (upper left in pic) mounted out of the way to allow future, custom tanks to be mounted below.

Nick

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Time to look at the main gear and how it is mounted. The struts are very near scale down to the landing lights. The pistons appear to be very robust and the retracts lock in the up and down position. I tested the retract’s ability to hold air and they did without issue in both the up and down positions with the test repeated many times. As you can see, the retract mounting rails are thinly skinned with Carbon Fiber and those rails mount to two, honeycomb bulkheads also skinned with CF. I am going to resist “beefing up” those bulkheads even though I instinctively want to. I am going to trust FEJ on this at least to start.

Nick

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Nice Nick the j10 is very unique looking, I like that. So this the smaller version?
Can hardly wait to fly yours at Jets over Ky! :)

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Bob:

It is the "middle" size. They make it in a larger and smaller scale also....

Getting excited about KY Jets!

Nick

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Thanks for info Nick. I'm looking forward to Jets over KY too. It's nice having a major event like this so close to home.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Nick, what is the diameter of your cylinders? I want to see if the F-104 uses the same size. Thanks again, love the thread and appreciate the time it takes to post.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Nick I was told they stopped using the honeycomb/carbon on load bearing bulkheads, I would suggest fly it and keep an eye on it, it may need to be strengthened, sometimes they do a ply bulkhead in the area where the gear mounts and above it they will add the honeycomb/carbon as well. If this is the case any hard landing may cause the joint where the two meet to crack, with that said it all depends on how the load is in that area, it may be fine since you have two bulkheads sharing the load front/back. Unlike the f-16 that has one large bulkhead supporting the entire main gear.
After I saw mr djs video I saw them cutting full bulkheads with carbon/honey comb design, it does work great just isnt as strong as solid a/c ply with carbon. Plenty of these flying right now ask someone who has one to see, I think with two bulkheads sharing the load everything should be fine. looks like a nice clean install in that area.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Next, I decided to build the servo trays for the split control surfaces on the wing. Actually, unlike the EuroSport I have flown for many years (which has huge elevons on each wing), I was told by others in this forum to program the outer control surfaces as elevons, but the inner control surfaces as elevators only (just like the canards). The tray sides are made from the honeycomb material sides and ply tops. I had some concern about the sturdiness of this setup, but once I used Hysol to assemble they are plenty strong (plus they are going to be glued to both the top and bottom of the wing.) I “Hysol”ed the trays into the openings in the wing and then glued the tops of the trays to the bottom of the wing so they are fully secured. The hardware supplied by FEJ is new to me and consists of aluminum clevises with 3mm pins and c-clips plus 3mm pushrods. They appear to be high quality and I decided to use them (normally I just use my own hardware on jets). I was able to use the Hitec 7955 blue aluminum servo arms and supplied control surface horns, maintain mechanical advantage with the linkage, and still get the 40mm of elevator throw indicated by FEJ. I trimmed and mounted the four servo covers with BVM 3/8” long miniature screws. Two of the servo covers appear to have been removed from the molds prematurely (they were distorted) and I had to heat them with a heat gun to reshape them to their proper shape. The covers really make the wing look scale; nice touch! I am using Dreamworksrc “TBolt” (ASHLOK) harnesses to connect the wing servos and lights to the fuse wiring.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Nick:

Looking really nice. Keep working on her. See you at KY jets.

James

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Hey Nick,

I like that color scheme.[8D]

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

OK, more progress. I am guessing the J-10 will be similar to my Eurosport, in that, I will need to place all of the A123 batteries up in the nose to balance. One of the challenges with scale jets with a full cockpit and operating canopy is where to locate switches and charging jacks. On the J-10, the closest access hatch to locate any switches is the engine hatch. If the switches were located in the engine hatch (past the fuel tank), and with the batteries in the nose, the wire to the switches would be 51” long. Since the receiver is located behind the cockpit, the wire from the switches to the receiver would be 28” long. Total length would be 79” long from the batteries to the receiver. Even with heavy gauge wire and double switches, I believe the total length would be way too long. The only solution is to create a “new” access hatch. I chose a location just under and near the rear of the canopy (not really any other choice based on the internal layout). First, I strengthened the area with carbon fiber cloth and West Systems epoxy. Using a Dremel and thin cutoff wheel I cut the hatch from the fuse. I taped the hatch back in place then mounted two, offset hinges from the inside. I then created a “box” to house the switches and charge jacks. I saw Ali’s builder using magnets to hold his A-10 hatches closed so I decided to try that method instead of the usual hatch latch approach.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Looking good! Something to think about next, having the door open like a speed brake is a good way to prevent it from getting ripped off if it ever comes open flight. Make sure since u have yours opening into the dir of travel that you have a good latch.

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Thanks for the tip. I did know to make my hatches open in the opposite direction on my FEJ A-10, but based on internal bulkheads and layout in the J-10, unfortunately it had to open in the direction I have it.

Nick

RE: FEJ 1:6 Scale J-10 Vigorous Dragon Build
 

Cool deal nice looking bird is it going to ky jets?