Is this loud sound flutter?
 

Had a friend put my Lazy Tiger P51 in a start of a dive and heard this pop -pop -pop noise. Is this a control surface or is the wing sretching the rubber bands out and bouncing. this was a very loud noise.. I'm running a 32sx, which has pretty decent power. any Ideas how to correct? or what the heck is going on, I dont think a small surface could make that loud noise? Could it?

RE: Is this loud sound flutter?
 

It's a bit difficult to tell without actually hearing the sound, but flutter usually sounds more like a "buzzing" sound. But it's not out of the question that your popping sound could be flutter. You need to check all of your controls because if it is flutter it can destroy an aircraft in seconds. Make sure everything involved with the controls is tight and won't flex.

Ken

RE: Is this loud sound flutter?
 

Two things I would do, add a pair of rubber bands, and hold the plane by the wing near the fuselage. Shake up and down, and see if the fuselage moves. If it does, add 2 more and test again. Also, it could be some loose covering, go over the covering with a heat gun carefully, you will see fairly quickly when you hit a spot that's looser than the rest, it will make a sound. Also, check all of the seams where 2 pieces of covering overlap, a loose seam can get air under it, and that can be loud. Carefully tack / shrink it down some. This can happen to planes that see changes in temp. and humidity. I have been checking mine about once a year and have to tighten up something yearly. Good luck.

RE: Is this loud sound flutter?
 

Flutter and the cracking of balsa at 500 feet are distinct and unforgettable sounds. Maybe another club member can listen to the sound and advise.

Bill

RE: Is this loud sound flutter?
 

Can strip servo gears in an instant. Make sure there is no play in any of the linkages and hinges. I wouldn't let it do it till you find out what's causing it. Not worth losing a plane over.

RE: Is this loud sound flutter?
 

ever hear air brakes on a dump truck go off? something like that. or sometimes, like a playing card in bicycle spoke. the sound is more low pitched, somewhat slower and will possible resonate through the airframe, making it quite loud and distinct.

basically, a flapping-sound.

RE: Is this loud sound flutter?
 

You also might want to put some clear cellophane tape over your hinge gaps. Many times flutter is caused by air bypassing through the gap.

RE: Is this loud sound flutter?
 

Most flutter sounds like a low to mid range buzz, i.e. a large flying bug. However, I have heard flutter that had what I would consider an abnormally low frequency. I would compare the sound of this lower frequency flutter to a bicycle card in the spokes. So, you probably heard flutter. Like others have posted, check all hinges, hinge gaps, control slop, servo's, etc.

RE: Is this loud sound flutter?
 

If you are experiencing flutter, it is probably coming from the elevators. The junky pushrod that comes with plane needs to be replaced with two straight metal pushrods running straight to the control horns and connecting just aft of the servo arm. This took care of my flutter problems for good.
P.S. just sold mine last week after 4 years of flying the snot out of it with a 32sx.