I just noticed that this only has 1 aileron servo controlling all 4 ailerons. Would there be any major advantages to converting this to dual servos? If so is there any method to determining where on the wings to mount them? I would assume that I want them as close to the spars as possible.

You would minimize control link slop by the direct link to two of the ailerons at the expense of a couple of ounces additional weight.

Many have said "what ever you do you should be using 4-40 hardware for the links between the two ailerons on each side....4-40 wire....very stiff or you may experience contro surface flutter.

You could always bash it if you like. I have the .40 size ultimate from GP and I have used the one servo for almost 2 years now without any issues. If it is the .40 size, get a good servo and stop worrying about it. I have to say it is a great little plane. You will love it.

Crash90, just wanted to let you know that I had the exact same worry as you do. When I was building my GP Ultimate I really just didn't like 1 servo controlling 4 surfaces. So, what I did is I placed 2 servos in the lower wing between the 5th and 6th rib from the tip. That basically put it just past where the sheeting stops on the center of the wing. I had to build a little hatch in to the wing for servo, but that wasn't that hard. You can either build one yourself, or I've heard good things about the ones from www.jbaccesspanels.com. Some may say it's overkill to add the second servo, but I've never seen an ultimate with a roll rate anywhere near mine, so I'm going to stick with the 2.

Thanks everybody. I am building the left wing on my GB US40+. I will trace the servo mounting tray and install 2 low profile servos. It cant hurt. I will be powering the plane with a saito 72 so a few ounces of weight wont hurt any.

I too did the 2 servo, bottom, wing conversion. Mine has an OS 70 in it and the power is a little on the low side. This plane has a very thick wing and it takes a lot of power to make it fly. It does one of the nicest inverted flat spins you will ever see. I like how the plane flys but it completely lacks vertical performance (prop APC 13X6 @ 10,000 RPM). Good Luck!

Here is a picture of my wing:

Phil (Mesa, AZ)

Here is a picture of the plane all assembled. The only mod, besides the 2 servo conversion, was to add a pull pull setup to the rudder. Much easier and effecient than a single rod.

Well, here is a picture of mine before I covered it. I added a half rib in the highlighted area. Between a stock rib and this half rib lies the servo tray. I made a simple rectangle tray out of ply that the servo screws into.

Phil (Mesa, AZ)

Help also!! I had the same thoughts so I just built a wider tray in the center of the bottom wing and ran supports to the spars. There seems to be plenty of room for two servos between the fush sides did I do something wrong? Why would you want the servos outside the fush in view?

I BUILT MY ULTIMATE WITH 2 SERVOS ALSO . I MOUNTED STANDARD SERVOS RECESSED IN THE LOWER WING. INSTALLED OS46FX BUT HAD TO ADD 12 OZ OF LEAD TO THE NOSE. LATER INSTALLED TT90 4stroke NOW HAS UNLIMITED VERTICAL. I LOVE IT. :

I also went with two aileron servos in the bottom wing. I Used the method that is used on the Sig 4-star. The ailerons are mounted to plywood hatches that are fastened to rails that I glued in the wing. The hatches fit flush with the bottom of the wing.

Here's what it looks like.

Here it is with the hatch removed.

Here's the plane. Unfortunately it had a midair last summer. I'll have to rebuild both wings, but the fuse is OK.

Last one, her it is during an inverted low pass.