On my fourth flight of my Sig Cap231 EX today I was having a hell of a time controlling the plane. After a nerve racking attempt at an approach I was able to land the plane undamaged. Upon inspection I discovered that BOTH aileron servos (9202's) were stripped. I had heard what possibly could have been flutter early in the flight, but with others running their engines close by it was hard to tell. I am very happy that I was able to land it safely with little or no aileron control, but puzzled as to the cause. All of the hinges are in solid, the gaps are minimal and sealed, and I am using a DuBro anti vibration mount for my Saito 180. Could the servos not be strong enough to handle the load, or is it a case of 'I should have got metal gear servos'? Any help you could provide would be great. I want to try to avoid $#@# in my pants next time I fly this bird.

Thanks,

Mike

Hey Mike,
This is problem that alot of people have had, including myself. Maiden flight, lost both aileron servos due to flutter. Couldn't recover and took hit home in a bag. That took along time to get over. A member of our club flew his sig cap today for it's maiden and the same thing happend. Completely tore the right aileron off. He, like yourself was able to limp it in to fly another day! Most people don't get a second chance. I have talked to Sig but they were no help at all. The one thing they did say was you have to use metal geared servos. As to the reason why, I personally think it is a design flaw with the aileron itself. not sure if it is the weight of the control surface or if the surface area of aileron is to large for one servo, either way I would use a metal geared servo. also, make sure to use a short servo arm. your control throw will be reduced but you will gain some mechanical advantage for the servo. Hope this helps and you get back in the air.......and stay there

Airborn

I have one of these and use Hitec 605's for ailerons and elevators. I use a 615mg on the rudder. I started with 9202 servos and they worked fine until I cranked up the hp on my ST2500 and went to an 18X8 Mezjlik. I recently ripped the right aileron off, a big evergreen caught it for me with slight damage! Use the higher torque servos and you will be fine (65 oz in or more as recomended by SIG).

I had the same problem with a Sig Extra 300-the deal is THE AILERONS ARE HEAVY! I too lost both ail servos. The best fix is to rebuild the ailerons lite and maximize the geometry of your setup and to use high quality servos. IMO.

My .02

I was LUCKY to get that airplane back down with rudder only.

Has anyone tried balancing the ailerons so that they are balanced at the hinge line? I have seen articles in the mags that show how to do this and it doesn't appear too hard...

Just a thought...

I think I will upgrade all of the servos to MG. I think the Futaba S9451's(120oz) for the ailerons and the elevators and a S9350(138oz) for the rudder should take care of the problem, or at least prevent it from happening again. What do you think?

Thanks again,

Mike

You'll be fine with those. I'm using Hitec 605s with no problems (servo wise).

were you flying around at full throttle?

I was flying straight and level at 1/2 - 3/4 throttle.

I flew mine alot for just about a year with Futaba 9202 servos and never had a problem. The plane was powered by a ST 3000. I was never gentle with it and the ailerons and elevators were always crisp and responsive. As a matter of fact I had to reprop the plane to slow it down. Sorry to hear about your problems. I guess I finally got lucky for a change.

Mike, about a year ago this was the hot topic on RCU. Several were losing ailerons on the first flight. One of my buddies and I both have been flying the Sig 231 for over two years. We both run Saitos 180s, I run 15% and manage the throttle on down lines while he runs 30% and is blur on up and down lines. Neither of us have ever had any flutter. I can't remember the number but I am running 69oz Futabas with nylon gears.

I think the guy earlier who stated a heavy aileron caused the problem is correct. After about a year I dumb/thumbed my first one in. It is such a great flying plane I immediately ordered a repalcement. Taking the parts out of the box I noticed one of the ailerons was much heavier than the other. On the scales it came out to three and one half, thats right 3 1/2 times the weight of the other aileron. When striking the work bench with the heavy one it sounded like a ball bat. Luckily I had salvaged the airlerons on the old plane and used them. My thoughts are the heavy ailerons strips the gear, next comes the flutter.

Gary M

Boy's I had the brush with disaster and I have the brush to prove it, It still stuck in the controls of the plane...I was trying to land being coached by the Russman...My first real scale plane, I'm used to pulling back on the throttle on final and flaring...Not this animal, It don't like to fly slow...Well, coming in I was set in my ways and was trying to flare to early and SNAP, well it took a left into the broom straw, I thought Its gone, waiting for the BIG BOOM, I don't know what got into me but as a last resort I floored it and pulled all the way back, next thing I know she pops up out of the field, and I scream take it, take it...Well, I tried it once more, this time it was even more spectacular, It snapped left, went inverted, and some how, I pulled it out too...Thanks to the G2, it still lives today...I have got to correct a bad habit of flaring too soon and throttle management...That was my weekend and I am still shake'n...Kneesaknock'n

I have a cap 232 from cmpro with a 120 2 stroke in it has about a 66" wing span.

Today I came in and landed and notice all the CA hinges on one wing came out, is this a sign of to high a load on the wing alierons?.. I'm using JR 591 servos are these strong enough on a plane this size??

Extremely important to close the gaps I am guessing.
I hear some people don't bother and others will not fly a trainer without doing it.
I figure for the cost of a couple of strips of mono and the 15 min it take's why not?
Lean540