I am building a Lanier Ultimate Bipe, and was thinking about modifying the ailerons to be longer span so that they will be within the prop wash for control during hovering and High Alpha maneuvers. In the plans, the ailerons are pretty large, but short span, and they go from the wing tips in towards the fuse and are about 2" X 6" (I'm gussing because I'm at work). What would be the effect if I went with a 1.5" aileron, that didn't go all the way to the tips (maybe start 1 inch from the tip) and went in to about 5 inches from the fuse (I'm using a 18 to 20 inch prop). That should get all 4 ailerons 5 inches into the prop wash.

Any ideas?

Have a look at Chip Hydes TOC biplane for guidance on how wide to make the ailerons. Based on your sketch I would suggest that keeping them the same width and just continueing the hingline inward would be fine. In your sketch the ailerons are not overly large by % of the chord.

I also would keep the ailerons at the same chord and just extend them to the fuselage. Due to the shorter moment arm, ailerons close to fuselage are not as effective as ailerons out at the tip. Even with prop blast, you will need big ailerons with lots of throw. Another thing to consider is that the ailerons may need low rates to prevent getting too sensitive at higher speeds. Are the elevator and rudder big enough to provide adequate control in hover?

I'm just a Pattern interloper, but all the Ultimate rudders I've flown have ridiculous rudders in terms of control harmony---way too powerful---on the one model bipe I have now,in its 3D settings, the rudder needs to be at +- 25 degrees, instead of the common 45+, in order not to swamp the ail/el response.

tmproff,
If you're wanting to 3D the biplane, and your picture describes the planform you expect to use, I have a suggestion.

Take a look at all the 3D biplanes you can find. I think you will see that almost every 3D airplane has ailerons that are a considerable percentage of the total wing chord. The picture you've included shows ailerons that would be marginal for 3D.

3D airplanes fly the 3D maneuvers on the prop and get their movement then from prop blast on the surfaces. So they have lots of surface to their ailerons, elevators, and rudders. And they often have very large "aerodynamic" balance proportions in those surfaces. Aerodynamic balance areas often cause those surfaces to stall at very shallow deflections. So they're often lousy for non-3D flying because they're so apt to hit the airplane with the massive drag that a stalled surface creates when flown at speed.

Take a look at some of the TOC biplanes for example.

Well I decided to cut out the extended ailerons this weekend. I am using 2" aileron stock from the LHS, and I extended it to about 20 inches. As to the tail surfaces, they are HUGE. Due to the way I usually build elevators / rudders, I added about a half an inch (triangle stock for better deflection on both surfaces). When I get all 4 done, I'll have some pictures. My fear is that since I'm going to be using only one large 168 oz torque digital (HS 5645) servo per side, I didn't want to make the ailerons too huge for fear of flutter in dives, etc.