Twister - FINISHED, DONE, READY TO FLY!!!

[Colin McRae]

Thanks.  Actually, I have and am still considering putting heavier wheels and an APC prop.  I will have to cut the spinner opening if I do.  However, I don't have an appropriate size APC. The prop on it now is a new TF wood 11 x 5 (old school) prop.   I would like to see if the heavy prop nut gives a smoother engine run, due to the flywheel affect. 

BUT, I still have no solution to getting somebody to fly with.  My flying buddy (Jim) is still too sick to participate.   I have a back log of planes to test.   I have my ringmaster that I did fly twice and made some changes to that needs flying.  I have my Vector that I have never flown and now the Twister is waiting.  I'm not complaining, this better than having no planes.  What size APC do I use for a FP40?

I cut into Dubro spinners all the time to fit a prop when needed. Not a big deal. Just remember to check the balance on the spinner.

Is your FP 40 the newer ABN design? The first-generation FP's had iron pistons and steel liners. But at some point, OS upgraded to ABN metallurgy. But OS never changed the FP designation. It is easy to see which one you have. The older iron/steel design has a bump on the side of the case.

I have a SIG Banshee which is about the same size as the Twister. I used to have a 40 FP (ABN) on it, but it was just too much engine for it. Plus, I needed to lose nose weight as the 40 FP is quite heavy. I went to a lighter OS MAX 30 and was able to lose a bunch of tail lead weight. Overall lighter model. The model was transomed and flew great. The MAX 30 power was fine for the Banshee and is probably a bit more power than a Fox 35. I am running an APC 10-5 on the MAX 30. Somewhere around 9,800 rpm.

The 40 FP will easily turn a 11-5 prop. So, I would try a 10 or 11 inch diameter prop with low pitch say 4 or even 3. You can even cut an 11" down to 10.5". You'll have to test the various props and corresponding ground rpm to achieve the lap time you want. Probably something like 5.2 seconds.

And don't be afraid to tone down the power of the 40 FP by using a smaller venturi. I believe the stock venturi for the 40 FP is 0.283". I ran my 40 FP with the venturi off of a stock 25 LA (0.257"). And even smaller ones are available from James Lee (Lee Machine Shop).