[pianodude]

i just reread the above post(it was another 12 hour day!!) i am using my first OS .46ax and it GOBBLES!!! the fuel. five or six minutes max on a ten ounce tank.

[pianodude]

i flew mine and have the exact same issues in every respect. quite a handful to fly. not difficult, but certainly not for a beginners...

[AJCoholic]

Just to follow up - the Sig WOnder IS a very stable plane provided the CG is correctly set, it is not overpowered (read that as heavy) and the control throws are kept reasonable.

It can be a handfull, especially if the throws are set wild. Small planes in general need a LOT less throw than many realise.

Keep working at the set up untill it grooves in flight.

AJC

[RCFlyingKnight]

I flew my Wonder again Tuesday night. It was very calm so I was able to get a good idea of what it was doing. At half throttle it wouldn't climb on it's own but it was making a reasonable flat turn to the right. Tried a couple of loops heading straight out from myself, plane exited the loop to the right of where it entered. Going vertical to a stall the plane would always fall off to the right. The only thing I haven't checked is the wingtips to make sure they are not the cause of the right yaw.

This is becoming quite the learning experience

M. Smerdon

[pianodude]

i have put about ten flights on mine now. it is not fun to fly. it has negative dynamic stability. no matter where i put it, it doesn't want to stay there. level, it wants to climb, level out it wants to dive, etc. i have triple checked the cg, throws etc. i am at a loss here...

[Guest]

pianodude, what are you using for servo's? Are you sure there is no slop in the elevator servo or is it perhaps a cheap servo that doesn't center well? When you bolt your wing on, does it sit tight in the saddle? no movement anywhere?

Reason I ask is that I have had quite a few wonders in the past and no word of a lie probably have 6000 - 6500 flights on wonders. I have worn engines out on them. In all of those flights the ONLY one that was a bit of a challenge was my Nelson powered one, and that's only because it was clipped wing, thinner wing, and heavy. But it still was not what I would call unstable, just fast and heavy. All my other wonders flew beautifully. One of my favorite things to do before landing was to climb until it was just a speck and kill the engine, then do aerobatics all the way down. I bet I got a good minute and a half of glide time with them.

It sounds to me like the biggest problem you are having is centering of your elevator, if it wants to climb in hands off flight, but dives after you correct it, that tells me the elevator is not coming back to center all the time. This could be a bad servo, slop in the linkage, or heavy binding in the hinges (though if you used CA hinges that shouldn't be an issue).
Although not a precise airplane, the Wonder is so short coupled there is no room for a sloppy or innaccurate servo. I used JR4131's in my later wonders, in the first ones I used the JR537's. Just a thought.

[pianodude]

hey LGM. i am using futaba micro metal gear servos(S128 i think). definitely not cheap($38 apiece). there is no binding at the elevator and the cg is spot on. the only thing not to plan is the motor(o.s. .25 fx). the saddle and everything else checks ok. the thing is fast, but not crazy fast by any stretch. maybe i sshould move the cg forward an eigth of an inch or so. what do you think?

[Guest]

Hi Pianodude, the S128 isn't a metal gear or micro, it's an old Futaba standard servo.
If you are using a micro servo though that could very well be the problem, how many screws hold the servo in? If it's just 2 like most micro's you could be experiencing twist in the servo case itself. I always used a standard size servo in there as there is a much larger area for the servo to mount to. Also make sure your servo mounting blocks go all the way across the fuse, in other words, don't have the servo mounted to only one fuse side.
Lastly, a cored motor servo will not center very accurately compared to a coreless motor. If the servo is an older one (been used) it's possible there is some backlash in the gear train as well (common on metal gear servo's) Or it's entirely possible the servo is not strong enough, with a 25FX I would use no less than 50oz of torque.
As for CG, I believe I balanced all of my wonders right on the spar so that it had a slightly nose down attitude.

I would recheck the CG, and I would swap out the micro for a standard size servo. You don't have to use a coreless or a digital servo, but I would at least use a ball bearing servo with 50oz of torque.

The wonder is a lot of fun to fly, it's worth working the bugs out.
Where are you located BTW?

[pianodude]

finally figured out the problem.. balanced as per the specs, my plane was a little tail heavy. took the weight(half an ounce) out of the tail and it was rock solid at all speeds... that is until the last flight of the day. did not have ANY control on takeoff and it now in the trashbin.... ah well, another day at the field....

[AJCoholic]

Sucks about your plane... but it was good you found the problem. Yes, a plane that hunts in pitch is a sign of tail heaviness, thats for sure (been there) and the short coupled planes like the wonder are ore prone to any out of balance condition.

At least if you want another, the kit is cheap and you can build it in a few nights.

AJC