My Extra 300
#1

So I bought an ARF Extra 300 and I was pleasantly surprised at the quality of the plane. All wood construction with beautiful covering. It was a .48 size nitro powered plane, so I put a .61 2-stroke on it to be sure it performed as good as it looked. Now I am a novice flyer, so I'm a little apprehensive about flying this fast plane. Maiden flight was going well at about half throttle when I decided to open her up. Full throttle, high-speed fly-by and something went horribly wrong. I heard a terrible buzz and lost elevator. She went into the woods like a missile. After forensics I noticed most of the teeth on the elevator servo were gone. The buzzing that I heard was the elevator flapping as the long composite push rod flexed. I contacted the manufacturer, explained what had happened, and they sent me a new plane. I relocated that elevator servo about 4" from the tail with a short rigid steel push-rod, adjusted the C.G. All good now.
#2
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Yep - flutter can and will destroy some components real fast. Now you know that the next time you hear that sound, you should reduce throttle immediately, land, find the cause and fix it before you fly again.
Is a .61 2-stroke larger than the recommended engine size? If so, you are very fortunate that the manufacturer replaced it, on their dime. Care to share who makes the plane?
Is a .61 2-stroke larger than the recommended engine size? If so, you are very fortunate that the manufacturer replaced it, on their dime. Care to share who makes the plane?
#3

Actually I think the .61 was at the top of the recommended engine sizes. It was a Graupner model, similar to this pic. except Patty Wagstaff was the pilot figure.

Graupner

Graupner