I recently seen a Seinor with flaps, and I was amazed how slow it could fly and the short takeoffs. I was wondering just how much work it would be to do this to a 40 size Tower trainer. I am kinda new to RC flying, and I have kit built all of my planes. I am unsure if it can even be done with this airplane... the wingspan is 56" and with 5-6" flaps, would there be enough aileron to turn the plane?

Thanks.

Would be easier if you had Ail-Flap mix on your radio. Otherwise I dont think it would be worth it. To much work, and a trainer really does not need Flaps. I will also add, cutting down the Ails 5-6 inches will make a huge differance in banking.

Hypter,

I don't think there would be a problem with this modification. You might want to increase the chord of the ailerons to compensate for the lost span, but even that may not be necessary. You could also increase the aileron throws. This plane generally is not expected to have the kind of roll rate that fun-flies do, and the outboard portion of the aileron is the most effective anyway. It's kind of a marriage made in heaven, since the flaps want to be inboard, and the ailerons want to be outboard. As CHassan says, this plane doesn't really need flaps, but if you would get a kick out of it, go for it and don't worry about aileron authority.

banktoturn

Thanks to both of you..

I think I will go ahead and try it, I know that the trainer doesnt really need the flaps, but thought it would be fun to try and it will give me something to do. Banking the plane was my biggest concern, I think I can go with some wider ailerons and increese the throws... in theory it should work?

again, thanks alot to both of you. maybe ill post some pics of the progress.

Right on the button! I have done this to a number of trainer style planes. Make the ailerons and flaps about 50% larger in chord, and make the flaps about 30% of the wing half. It's a blast to have this on a plane, and really helps with float planes. For short take-offs I use 15-20 degrees with 30 for landings. There will be a MAJOR trim change with the flaps down so be prepared, if your using a computer radio you can mix the change with the flaps. Have fun

It can be a relatively easy mod too. There are basically two ways to do it. The first is the easiest... Flapperons.

If you don't have mixing, you can make flapperons with a configuration like this...

The other is to cut about 6" off of the inboard side of each aileron for flaps and use the torque rods to move them, then run the ailerons with either a servo in each wing, or one servo in the middle with Nyrods running out to the ailerons.

In either case, I wouldn't extend them until I tried them out first. As was pointed out earlier, the outboard end of the aileron does 90% of the work anyway.

Nice diagrams Minnflyer! For simplicity, flaperons are really appealing, and might give you all the extra lift you need, especially if they have enough chord. From an aerodynamics perspective, I prefer separate flaps and ailerons, to assure that you retain aileron authority at low speed. This is definitely not a problem for every plane, but the low speed situations in which one would use flaps are the kinds of situations in which aileron authority can be a problem.

banktoturn

I agree with Banktoturn, the most you can droop flaperons and still have good aileron response is about 15 degrees, and although this does produce considerable lift, it does not create the large amount of drag that you get from 30 degrees of flaps. Drag is a requirement for STOL performance. Drop the flaps, point the nose down at 45 degrees and the plane doesn't accelerate, pull out 5 feet from the ground and end up with a 20 foot ground roll. Now thats fun!
The reason I always increase the chord of the aileron is because the plane will be able to fly much slower than the original design, and the extra area keeps the roll control from getting too mushy and slow.

True, I should have mentioned that separate control surfaces are definitely better for several reasons (for example, tip stalls will occur more frequently with flapperons then with inboard flaps). flapperons are just the easy way out.

The old Hobby Lobby Telemaster 40 trainer was orginally designed for torque rod flaps and bellcrank ailerones. They work great and are very helpful for some beginners.

Plus I really like landing backwards in a stiff breeze

Bill