Let me say up front that I haven't completely worked through this yet, but am taking it step by step. I have an Ultra Stick Lite with a Zenoah G-26 for power. I maidened it for the first time this last Sunday and I and my instructor noticed a few things that may need correction. The plane was balanced at 4 1/2" as indicated in the instruction manual. I did balance it (less fuel) leaving a little nose down in it for easier handling after fuel is gone. During trimming we noticed that it needed a lot of right rudder and aeleron trimming along with up elevator to create level flight at about 1/2 to 3/4 throttle. I have gone back with an incidence meter and checked the engine incidence finding that it actually had a little left thrust and 0 degrees on the up and down. I have corrected the left thrust portion and am planning on leaving the engine thrust at the 0 degrees for up and down. Next step is to check the wing incidence and to determine "if" we need to add a little positive incidence to the wing. My question is this: If we decide to add about 1-2 degrees of incidence to the wing, what is the best way to do this.

One recommendation that I have received is to lower the rear of the wing, but this would require a changing of the entire wing saddle from front to back. (At least that's what it looks like to me anyway.) The other option would be to raise the front of the wing to increase the incidence, but this too has some modification that would be required. I am considering the second option of raising the wing and adding shim strips under the wing on the wing saddle, but would appreciate any input on how to do this without losing the good fit that I have with the wing dowel set up on the front. I thought I might fill the holes with dowel material and remark them and re-drill, but not sure if this is the route to go.

Any help on steps to change the incidence and still maintain the wing's good fit to the dowel holes would be appreciated. BTW: I did reinforce the dowel bulkhead by adding light ply to the front side of the bulkhead, and replaced the lousy wood dowels provided in the ARF with solid oak dowel material.

Hope I have put enough information in this post. Sorry for the length, just wanted to make sure you had what you needed.

I'd start with the thrust angles on the engine first....I'm sure you're going to need both down and right thrust... I'm not sure the exact numbers for the USLite But on the original US120 I had 2 deg down and 2 deg right.. Proabbly could have use more on both.

It's far easier (and easily reversable) to play with the engines thrus line VS changing the wings incidence (BTW did you ever measure the wings incidence??? I'm guessing it should be around 0)

Yep, I measured it as soon as I got home from work today. It is plus 1/2 degree, so we have decided to leave it alone for now. I must say I am surprised at needing down angle on the engine. Can you elaborate a little on why this would lower the tail and reduce the need for up elavator? I would think that down thrust would tend to raise the tail and that's what we are trying to avoid. We are working towards lowering the tail for less down force on the elevator. You are right about being able to adjust it easier though. I can add a small washer to the top mounting screw on the engine and get a little down thrust.

i missread that you needed up elevator (plane wants to go down).... it went thru my brain the opposite.... I think if you call horizon they'll be able to tell you all the inceidences and thrust angles they where shooting for when designed..

hookedonrc,

I have the USL with a G-26. Iim running 3 degrees right thrust and zero downthrust. It required the normal type of trim adjustments, but not much on the rudder. 35 flights so far. The thrust seems to be about right - it tracks good on take off, straight on vertical up lines. It requires very slight down elevator for inverted flight and it's the easiest plane I own to hover.

Servos and battery are in the tail, tank is on Cg, engine is mounted with standoff dowels directly into the reinforced firewall (no aluminum mount plate or plywood plate). Minor work done on lightning the engine. Cg tward back of range, dry weight about 10.3 lbs.

Greg

Greg,
With the adjustments that I made in the thrust, I too am running 0 degrees down thrust, and about 3-4 degrees of right thrust. I am going out to the field after work today (weather permitting) and we will fly it again. We think that with the change from left thrust in the engine to right, and the fact that we do have a 1/2 degree positive incidence in the wing that it should trim more like yours. As far as construction, I did add an additional firewall to the front using 3/16" light ply, and I moved the elevator and rudder servos to the rear of the tail. I also am using a pull pull configuration on the rudder. The battery and receiver are in the servo tray area where the rudder and elevator servos would have normally been. I did not move the tank to the cg, but could always go back to do so if the adjustments that I have already made need a little more. Will let you know how the flights go today.

hooked, I'm going through this exact same thing with the little one (Ultra Stick 40). Specs are:

OS 70 Surpass
Quad flaps with standard (S148) servos all around
CG at rear of recommended range, with rx battery mounted just ahead of the horizontal stab

The maiden flight showed a severe pitch-down problem. I added engine up-thrust and reflexed the flaps; this helped, but the model still doesn't fly neutrally stable in the pitch axis. I was thinking it was either wing or stab incidence, but now I'm wondering if the thing is simply nose-heavy.

To answer your specific question, the only ways to add positive wing incidence on this ARF is to lower the rear of the wing saddle or raise the attachment point dowels. The wing saddle, IMO, would definitely be the lesser of those two evils. But personally, I would abandon the model before I went through that hassle. I bought this thing for a quick throw-together for something to fly while I finish up a couple of other projects. It doesn't fly well enough for me to invest the necessary time for a major re-work. And to top off everything else, the epoxy securing my vertical fin failed; the fin/rudder simply pulled out of its slot when I grabbed it to back the model out of the pits for another flight Sunday. Now, I have to wonder... did I improperly mix that batch of epoxy, or are both tubes bad???[&o]

Anyway, before you commence any radical surgery, do this quick test; from straight and level flight at full throttle, climb to a 45 degree up-line and roll inverted. If the nose drops quickly (like mine did), you're nose heavy. There is plenty of room behind the wing to cut a hatch into the bottom of the fuselage for the rx battery.

This certainly wouldn't be the first ARF that had incorrect or overly generous CG figures given in the manual.

That's what we will be doing this afternoon. As indicated, I did leave some nose down when I balanced it and I could make minor corrections to this if needed. I have also read on RCU where the balance point has been moved by some back to about 5-5 1/2 inches, which I may do as well. With the small amount of weight that I have to add and the power of the G-26, I won't be giving up very much performance. And...I can always move the battery further back if necessary. The change in the wing saddle or mounting points will be my last resort. And finally, that is not to say that the plane doesn't fly well now, quite the opposite. We just want to work on the charactersistics for better handling.

Let us know how she did.

I'm still debating on whether or not to continue working with this model, or bag it. The vertical fin is an easy fix, but I've got an uneasy feeling that the epoxy is bad; and all critical points on this model were done with the same epoxy...[]

Well, wind didn't cooperate this afternoon. It was gusting from 10-20 mph. Flyable, but not the best conditions for fine tuning the trim and incidence checking. So I thought I would add a few pics of the plane so you can get a good look before I report on the flight testing on a better day.

You gotta love this airplane, I finally got mine on the scales today. 11 1/2 pounds with an MVVS 26cc gasser and 9 oz of fuel in the tank. This should be everyones first big plane/gasser!

My engine looks like a .49 glow compared to the lumps some of you boys have been hanging off this plane! I have unlimited vertical and half-throttle hover with this combo.

I did mount my servos in the tail, but I mounted them internally with little fairings to cover the push-rod exits. Some day this plane will end up on floats, I didn't want that servos exposed to too much water. A buddy engineered a very cool mount that makes this possible, wish I would have taken photos before it went into the fuse, but I was in a hurry to get it in the air.

Dave,
My instructor has the older version of this Ultra Stick (the 120) and he has a G-23 for the power. I have been drooling over it for quite some time and mostly since the G-26 became available. And since I was able to pick up the engine from a fellow club member for $100 after only 1 flight, I just couldn't resist. He had it on the older version as well, but it flew away one day and ended up in a field where the cows pretty much stomped the plane to pieces. After several weeks of being missing the farmer found it and returned it. The engine runs just like the day it came out of the box, with only a few areas that have a little rust from the time spent in the field. I know it is a pretty big lump hanging out there, but that lump sure has a lot of power.

OK...here's the latest. (and the best) I got the plane back in the air on Sunday and flew most of the afternoon. Also got out yesterday after work and flew till almost dark. The right thrust change was just what the Dr. ordered along with a 3/4 oz lateral balance. What an awsome flying plane. The G-26 is great and provides smooth an consistent power. The vertical performance is terrific, although I would not call it unlimited. Looks like the only thing that I might do is add 1/4 - 1/2 oz of balance to the tail to bring the nose up a little. However, I am not really planning it presently. If you get a chance to and want to add this plane and engine combo to your fleet I would recommend it.