Filken's P-38 Build Log

[jpot1]

I have built about 15 different FT models over the years along with various plans from MesaRC, Lockey (RCGroups) and others and was looking for something different and challenging. I had never built anything with two motors and was initially looking at the FT Bronco. There was not a lot on the forums for the FT Bronco and then one day I stumbled across the article by Filken for the P-38. I had built his corsair which flew great so I knew I had to build it. This thread will hopefully help someone else that wants to build this plane as I took the original plans and "enhanced" a few things. I waited to make sure things were coming together before posting.

Below is the article that started it all:
http://www.flitetest.com/articles/p38-lightning-twin-engine-goodness

 

[jpot1]

Reserved for final pics and hopefully video.

 

[jpot1]

I started with building the nacelles and the main portion of the fuse. For the nacelles the original plan had the bottom folding over in the FT spitfire style. I was uncomfortable closing up this area and still having to feed all the wires through. When cutting them out, I cut the bottom portion of the nacelle off and added the b fold paper to the outside edge, omitting the tabs as well as shown below.



This was a big help when running my wires. For the fuse I also deviated from the plans and did not use any of the fold over pieces. Instead I used the bottom of the fuse/canopy as the template to create the top and again added typical b-fold paper to cover the seams. Note the score line, this is not in the plans but is needed to match the canopy shape.

 

[jpot1]

I then moved on to the wings. Relatively standard to FT style but I also did not like in the article how Filken cut out the bottom of the wing to fit the servo. I was able to get everything to fit by adding the servo at the end of the spar and simply removing foam down to the paper on the wing bottom.



Built both wing halves, attached on the bottom with tape. The spars have the shape for the dihedral built it so I used that to set the dihedral and then did the fold-over. I reinforced the joint with a popsicle stick on either side.

 

[jpot1]

Probably my biggest learning curve was in regard to the wiring needed to utilize one battery to the two motor/esc combos. I followed the cruiser supplementary video but was unable to take one long wire, strip the insulation and get it to fit in one of the cups on an xt60 connector. Most likely the gauge wire I was using was too thick.

I stumbled across a youtube video that ( http://www.youtube.com/watch?v=4vLqajvCgdI) which was a huge help. I had the xt60 connectors, fired up the soldering iron and found 3/4" heat shrink at home depot. Followed one of the many differential thrust videos for my spektrum dx6 and tested everything out - woohoo - it worked first shot!

 

[jpot1]

Started to then put the pieces together. Note it was key to plan ahead and I had all the wires run and labeled, don't forget about the elevator - BEFORE - closing up the wing. I attached dental floss to the ends, shoved them in and then slid the nacelles and canopy over the wing and was able to pull all the connectors out no problem. Below is where I am currently at. Notice that by not adding the bottom covers on the nacelles it gives me much better access to all the wiring.

 

[jpot1]

The nacelles are not quite level but good enough for this build. To make sure the power pod sat even with the top of thanacelle I used a piece of foam as a spacer. It looks tilted but the wing has dihedral so the power pod mounting plate is parallel to the top of the nacelle.



Below with both motors installed and done foamboard wrapped to cover the top of the nacelle and bottom of the canopy area.



Quick test balance with a 3s 2200 sitting close to the front of the nose balances nicely!

 

[Flingn' Chopstick]

My favorite warbirds

I love the P-38 Lightning and the little celebrated history it has. It was such a crucial aircraft in the Pacific in WWII. I'll be watching how you accomplish this design and build. I'm really interested to see how she flies. Thanks for sharing.

 

[FoamyDM]

This is Looking really good. I love the P-38 in the simulator, and I REALLY want to build one. This look VERY doable. Plans please when you're done!

 

[Ricci]

Subscribed!

 

[jpot1]

Well I did finish it off and did fly it but it was a mess. The undercamber on the wingtips was way too much. I could visually see the outer 5 inches or so of the wings flexing as this turned. I was able to land and could see visible creases in the foam on the opposite side so parked this in the corner. The plans are embedded in an article on the form if you look under Filken as the author. You will definitely need to reduce the amount of undercamber. I took my electronics and put them in an FT Bronco which flew fantastic.