Help!!! Electric to Glow Conversion

[chuckywhiskers]

Hi, I'm going to be converting my FMS PA-18 Super Cub to glow fuel because I have happened upon a bunch of seemingly new glow engines and have gotten plenty of use out of this plane as is. I used to work on small engines, so I realize what a new engine looks like. Currently, I'm needing a new power system anyway and I figured this would be a simple way to get into glow.

Stock, this plane flies a 4S lipo pack (I run 4000 mAh 60C) and a 60A ESC with a 3541, 750Kv motor and a 12x6 2-blade prop. Am I right in my guess that it needs a .60 size engine? Or would a .40-.45 size be adequate with the right prop? I have never flown a gas or glow plane before.

I have looked at conversion charts, but they are all in the other direction (glow to electric), and I always wind up doing the reverse engineering mathematics for the charts differently. My brain is about fried from this and I would like some advice. I definitely want to get into engines, no matter what the people who preach electric are going to tell me. This is what I want to do because it is interesting to me.

Any tips on retrofitting a fuel tank, BEC, engine, etc... will also be much appreciated! Once next winter rolls around, I will build a proper balsa plane. For now, this is what I'm working with. Money is relatively tight, but not to a point where I cannot budget for a project.

Thanks a bunch!

[Evan D]

3541 is a 25 size motor... Look at specs of a eFlite 25 or similar.

By the size and weight of the plane maybe a .40?

[Raydar]

A 40 size would be plenty.

TBH this likely is not a great idea unless you are going to do a bit of work on the front end of a foam model, just slapping a vibrating engine onto foam or thin ply/plastic/whatever is there is not going to last or be safe. A 1/4 ply firewall is going to be needed and supported and tied in to the model at least to first former.

[chuckywhiskers]

I totally redid the firewall and first former with an aircraft-ply/abs/aircraft-ply laminate I made. Should be 3/8 thick mounting surface secured to the foam with reinforcing BBQ skewers glued in foam parallel to the thrust line. I put two 45 minute flights on her the other day. I'm happy.

[Evan D]

What did you end up using for power?

[chuckywhiskers]

I used a 500mL fuel tank that fit nicely in the fuselage, an OS Max 40FP that I got from an estate sale (along with several other engines), and a 2S LiFe for the receiver and servos. I'll take some pictures when I get home.

[Russell]

Is the fuel going to play well with the foam? Or eat it like gasoline. The FMS PA-18 1700mm is a foamy

[chuckywhiskers]

So far no problem. I have five 45 minute flights on it so far. I wipe it clean every flight and the only thing I could see happening is oil soaking in to the foam over time. It flies great and runs for about 50 minutes on a tank.