Split Ailerons?

[Trumpetman]

I've been flying my Dalton ML300 for a few years now and I built it with shortened ailerons with the idea of optimizing the airframe for IMAC (no 3D for me LOL). I've been very happy with this decision but I've always wondered how it would fly with full length ailerons.

I'm building a 2.8m JTec MC2 as a back up competition airplane and I've been kicking around the idea of using split ailerons. The outer ailerons would be my primary surfaces but the inner ailerons would be on a switch for use in certain maneuvers.

Questions

1. I know that this has been done in the recent past but I was wondering was the general concensus was about the legality? I've read the rules recently and it would seem that split ailerons are within the "letter" of the law.

2. Is the extra weight and complexity worth it?

Looking for your thoughts and input.

 

[Pistolera]

I've flown other friends plane with split ailerons in IMAC and have had many discussions. As the current rules are written, there is nothing illegal about them. I just split them on my 42% Raven and should have it in the air in a week or so.

Right now I just have a simple flap function for the inboards, using the outboards for all my sequence flying. I do plan on fiddling with adding another condition to allow both at the flip of a switch for 3D playing.

The only complexity is actually splitting them. To do a good job I think you'll need to remove them from the wing. Maybe not on a foam core, but on a built-up like the Raven it'd be difficult to do while still on the wing.

Oops....just noticed you're in the build stage, so no worries there! As for weight, while I didn't weigh mine before or after, I don't think I added more the a couple of oz's worth of ply/balsa to do them.
Once you have them split and installed.....NO MORE servo binding/matching issues!!!!

 

[Terryscustom]

No weight difference other than a couple of extra hinges at the split. I've built 5 planes now with splits and I usually split the surface area just about in half but I fly 3D primarily so my main goal is similar force on each surface. I've flown mine with just the outside ones for IMAC and it's just my opinion but I would make the outside aileron slightly larger than splitting the surface area like I do. Maybe 60/40. That would get the inside aileron out of the prop wash for IMAC but still have enough authority for good precision flying, especially when it comes to snaps, etc.

Again, I've never done one just for IMAC but if I were this is what I would do. Super happy I talked with @Pistolera about it and eventually gave it a try

 

[Trumpetman]

Thanks for the input guys. When I built my Dalton I set it up with the (approx.) 60/40 split that Terry mentioned and it has more than enough authority for IMAC precision snaps etc.

 

[Pistolera]

I now have about a dozen flights on the my 42% Raven with splits....and I honestly cannot tell the difference flying IMAC (Advanced) sequences. I haven't even changed the throws I had setup with the full span ailerons. Way more than enough aileron.....and landing with those big inboard flaps down is silly slow/short. I did mix in about 10% down elevator with flap deployment.

 

[Terryscustom]

I practiced IMAC with the inside stationary but I actually flew better with full ailerons.......but I also did better on high rates than low rates too so I'm kinda strange I guess.

 

[Pistolera]

My snap conditions (upline and downline) are dictated by the throttle position and both of those are high rate ailerons. The rest of the flying is between those throttle positions and has about 1/2 the aileron throw.

 

[Terryscustom]

My snap conditions (upline and downline) are dictated by the throttle position and both of those are high rate ailerons. The rest of the flying is between those throttle positions and has about 1/2 the aileron throw.

That's very interesting, I never thought of mixing rates to throttle.

 

[Trumpetman]

Excellent input. I'm just about to sheet the wings on my MX2 (JTec Radiowave 2.8 metre version) and I will definitely be setting them up for split surfaces.