Prawnik

Hey, all!

Today I test-flew my ArtHobby Thermic 2.5M, straight-wing version with ailerons/spoilerons. It flew well, penetrated wind well, showed good agility and climbed like a rocket off the winch. A contest glider pilot commented that this plane has the makings of a champion, but only if we solve one problem. The spoilerons are largely ineffective, which makes spot-landings an issue. On final, I gave full spoilers, and barely slowed down or lost altitude.

I am using Hitec HS-81 servos for the ailerons, set to maximum throws, and a low-end Futaba 6-channel computer radio to get my aileron/spoiler mix. The airplane uses tape for the aileron-hinges, as per the kit instructions. As ailerons, they were quite effective - the problem was in landing.

Does anyone have any suggestions to get more "oomph" out of the spoilerons? Will changing to a different transmitter give me more spoileron throw?

aeajr

My Feedback: (2)

The radio has nothing to do with it.

First - set your control rod at the hole furthers from the servo and closest to the aileron. That will give you maximum throw.

If you have already done that then you need a longer control arm on the servo to get more travel.

While you can probably dial some "some" extra travel from the radio, the biggest deal is the control arm on the servo. Longer = more throw.

BMatthews

For the spoilerons to work at all decently you need to basically throw them up at a 60 or more degree angle. That is not going to happen given the limits of a normal aileron setup. This is pretty much why combined controls do not work well. For contest type airbraking you pretty much need flaps or flaps combined with crow on the ailerons to really slow that puppy down. Just deflecting the ailerons up by 20 or even 30 degrees isn't going to do much.

aeajr

My Feedback: (2)

I have spoilerons set up on one of my slope planes and my buddy has them on his thermal glider. The work and they help. They are not as effective as true spoilers, but, at least on these planes, they make enough of a difference to be worth the bother.

I don't find that they slow the plane down much. They can shorten the landing distance. Get it low and rather than have it float forever in ground effect, hit the spoilerons and you will find it much easier to get it down on the level for a smooth belly slide landing.

May not be the best set-up for a contest pilot however for for sport flying, spoilerons will help, even if you only get them up 20-30 degrees. If the plane starts to dive, use a little up elevator compensation in the comptuer radio to help keep it level.

Your alternative is to cut in flaps or install reall spoilers on the wings.

Prawnik

I am going to email Andrzej at ArtHobby; he strongly recommends NOT weakening the Thermic's wing by cutting it for flaps or spoilers. Maybe he knows what to do. I have already used all the throw the servo arms and control horns will give.

I can probably get a few degrees more spoiler throw by playing with the geometry of the pushrods themselves, but I don't think it will be enough to make a difference.

aeajr

My Feedback: (2)

Can you extend the arms on the servos?

Johng

My Feedback: (4)

The wing lift distribution will be screwed up by reflexing the ailerons, which will cause more drag. However, if you are floating the plane in, the difference will not be very apparent. If the plane is moving along at a good clip, the spoilerons will burn off more energy. I suggest trimming for a steeper glide on approach, then use spoileron-elevator mixing to maintain that speed as the spoilerons are used.