CJM F-4D Conversion and Build
 

Lets start with a short background.
I purchased a CJM DF kit on RCU couple of years ago. The Kit was not as I expected when received, so I put it aside while working on other projects. Well I just could not get it out of my head and had to do something with it, so I called Bruce at CJM and they were able to send me the original plans. The more I thought about it, the more I wanted to convert this bad boy to Turbine, well I really did not like the one piece wing and wanted to change the design to CJM's updated version with the plug in wing. Armed with a lot of knowledge on RCU and the builders like John Reddman, CounrtyBoy, Split S and others I started the build which has been on and off for a while now so some of the Mods have already taken place. Here is a few photos of the original Kit I got:

RE: CJM F-4D Conversion and Build
 

Well after spending some time sorting things out, I had to repair some of the damage to the foam and a few other things.
I had to modify the wing and the Fuse basically at the same time to get things to line up. I started on the bulk heads, there seemed to be some mold problems with the wood, so I cut and cleaned them up. The wood is solid no issues. The foam core was marked by CJM but I added a few more on what I needed to do. Oh yeh, u guys like my wire feed tube? Late night and did not have any of the blue stuff, so you do what you can....hehehehehe.

RE: CJM F-4D Conversion and Build
 

Ok, next I had to cut the thrust tube to size and reconfigure for single turbine intake. The good old pink foam comes handy. cheap and plenty at the local HD. So I built a plug and made a mold to lay the thrust tube.

RE: CJM F-4D Conversion and Build
 

Ok, here is a few more photos of the fuse and the wing. I am setting up the wing for pylons per plan.

RE: CJM F-4D Conversion and Build
 

Now, it is time for putting the wing skin on using nothing but Gorilla Power, this stuff really works, the only problem was that the bottle would dry up after a couple of times till someone here on RCU had a genius idea to store the bottle upside down so the top portion of the glue (bottom side) would dry but the top would stay fresh and usable.... Thankyou whoever you were.

I wet both surfaces and applied the glue to both side and then pulled vacuum about 18 In Hg. worked like a charm.

RE: CJM F-4D Conversion and Build
 

I marked the Pylon screw holes and drilled for later insert installation. Now it is time for the outer wing, I put a bit more CF to avoid any deflection, call me crazy but I think that is just what the doctor ordered :D

RE: CJM F-4D Conversion and Build
 

Time for machining the plug in wing parts. Used T6061 MTL and machine to fit the wing aluminum spar. No I am not a machinist as you can tell, but I know enough to be dangerous :D

While I was working on metal pieces, I was thinking about the SS pipes, so I made my own welding station and bought some SS sheets to attempt making my own tube, most probably I will have to order one , but we will see if I can pull it off.

It is getting late, I will post more progress in the coming days.

RE: CJM F-4D Conversion and Build
 

Jsut Dry fitting the Main wing and outboard wing, fits pretty good. Second photo is the 1/8 ply to cap the foam and the dowel placement.

RE: CJM F-4D Conversion and Build
 

It is time for setting the wing box for the fuse. I used the plan and cut two Ribs, similar to the one on the end of the wing and squared them with respect to each other and installed it in to fuse and attached to the main formers. The main formers had to be modified a bit, added an extension to the ends to accommodate attachment to the wing box.

RE: CJM F-4D Conversion and Build
 

Next I capped the wings and installed two dowel rods, one on each end. I had made the same exact hole in the matching wing box rib.

RE: CJM F-4D Conversion and Build
 

Now it is time for the wing spar receptacle installation. This was a bit tricky, the receptacles had to be in line and parallel to each other, it took awhile but I think it came out real well.

RE: CJM F-4D Conversion and Build
 

I don't know if you guys have ever watched Bob on Youtube, he is got a lot of neat ways to build stuff. this next wing spar is similar to what he did in one of his shows.

RE: CJM F-4D Conversion and Build
 

Now that the Spar box is made, I held the wing against the wing box and used the two dowel rods to line it up and marked the wing where it lined up with the spar hold downs. I them cut two slot in each wing to accept the spar box.

I turned the fuse on its side and inserted the two wing spars in to the hold downs and put slid the wing on two the wing spar box. Lined everything up, added epoxy and microballoon mixture and glued the wing to the wing spar box. repeated the same process for the other wing.

RE: CJM F-4D Conversion and Build
 

Wow. I really miss building something.

RE: CJM F-4D Conversion and Build
 

FalconWings,

Know what you mean, it took me a while before I talked myself in to starting the build.

Best Regards,
Mike

RE: CJM F-4D Conversion and Build
 

While I was working on the wing, I was watching what CounrtyBoy and SplitS were doing on their F-4 (JL and ??). The stab hardware looked beefy. SplitS sent me some photos of the hardware and I started dreaming about a 3 Axis CNC machine. so I took some time off to build the circuitcard and cut the wood pieces to make a 3'X4' 3 axis router/CNC table. I need to get the full version of the software to do anything substantial. But it looks and works pretty good. I can use it for wood or aluminum parts.

RE: CJM F-4D Conversion and Build
 

I cut the aileron/flap section of the wing and installed the 1/8 ply to cap the end of the exposed foam, a strong base for the hinges. Again, nothing but Gorilla Glue. I will leave the Aileron/Flap section in one piece till the very end. Things will line up better.

RE: CJM F-4D Conversion and Build
 

Next, it is time to cut the wing servo boxes. Again, this trick was learned on Bob Tube. I used 1/16 ply wood to build the servo cover and its box. Basically, the servo cover is built using 1/16" ply and caped with 1/16" ply pieces on top of a 1/8" ply with the center removed. I then installed the servo box cover on to the wing.

Oh, forgot about the hinges, sorry no pictures, but the wings and Flap/Ailerons are also hinged.

RE: CJM F-4D Conversion and Build
 

Next, I worked on setting the mains in place and building a box around the retract area for cover installation later, not sure how to do it yet, but will figure it out later. I also lined the retract well walls with 1/64 ply. The floor was decorated with a piece of CF.

RE: CJM F-4D Conversion and Build
 

The mains do not fit inside the well, they are too long. There was a worn out mechanism to pull the mains and compress the spring as the legs were pulled in, but I think it was too cumbersome and may not let me install the wheel covers. So i used a 30Lb test fishing line leader to pull on the assembly as in is pulled in. I will have to test it later but so far it works. The picture shows the installation.

RE: CJM F-4D Conversion and Build
 

Next it is time to work on the spoilers, I cut the area per plan and removed the foam. The spoiler itself is made per plan using, ply woods, Carbon fiber and the plastic hinges. To begin with, I did not think it will be sturdy enough, but man o man it is pretty strong and no deflection.....

RE: CJM F-4D Conversion and Build
 

Next, I installed the 1/32 ply covers on top and bottom per plan.

RE: CJM F-4D Conversion and Build
 

Next , I filled the holes and uneven surface with Hobbico's Hobbylite Filler, the stuff is pretty good and dries in 15 minutes. I also dry fit the outboard wing, that is going to bit hard to line up and epoxy in place, I will have to figure a way to do this and make sure it stays put during epoxy cure.

RE: CJM F-4D Conversion and Build
 

If anyone has a good idea as to how to attach the outboard wing to the main wing and maitain the correct washout, please chime in. The only way I can figure it is to lineup the front end and the back end and then sand/fill once the epoxy is cured.

RE: CJM F-4D Conversion and Build
 

great jet your building, i dont understand your question about the outer wing part, cant you just place in on a table and messure the height?

PS. why does no one reply to these special threads, but are a person putting together another ARF and mounting servos, then people are replying wildly?