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RV-6 overspeed

F

floridawing

Well Known Member
Hello, I was doing a loop the other day, at the bottom I did not pull hard enough and allowed the IAS to reach 230 mph. The gmeter in the Dynon said 2.7 g's. The Dynon ems recorded 2730 rpm. I did not have any flutter. I have looked the aircraft over pretty well and all seems OK but am nervous about returning it to service. I would appreciate any information on what others in the group would look at before returning the plane to service. Thanks in advance for your help.
 
While you did top VNE, you did not come close to over g-ing the airframe and the rpm is so slightly over speed it is insignificant.

Go fly and have fun and let's be careful out there.


Glenn Wilkinson
 
loop

You do not say what engine or prop but assuming a four cyl Lyc, you just can't hardly hurt these engines. I operated the A4A in my Pitts for 1000 hours at 3300-3500 rpm almost every flight. The exception was cross country at 2500 to 2750 r/m. Your LIKELY problem with the loop is not that you didn't pull hard enough, but rather that you did not "float" the top enough. The entry and exit COULD be done at 2.5 G's, although 3 would be better. To dispel the "clean airplane" nonsense, I did a lot of loops in the Glasair I, 0 320, fixed pitch metal prop, no inverted system. The goal is to come as close as practical to zero g at the very top without causing a power interuption. With the Glasair if I did the loop properly with entry speed of 180, exit speed was 180, full power all the way around. If you are fairly new to this, as you approach the vertical down, if you sense you are going too fast, by all means pull the power back, all the way to idle if necessary. The ultimate goal is full power all the way around, entry and exit speed within a few knots. I met a gentleman years ago who had split s'ed a RV6 at near 300.
I would not worry about the speed you reached, just try not to do it again. Be VERY AGRESSIVE about pulling the power back if necessary. If you have not had some formal aerobatic training now would be a good time.
 
rvmike said:
A friend who self taught himself loops in a 6A told me that if the RPM goes over 10 percent of max rpm for a certain time Lcy says a tear down is mandatory. This could be a rumor but he was a perfectionist. Won't hurt to do some research. Also many older tachs are way off calibration and your efis could be also. I would not worry about the airframe.
Click to expand...

His tach would need to be off by 300 RPM or more for this to be a consideration, if true.

Agree with the others, learn from it, move on. Remember Vne also has a margin of safety before flutter speed, although that's not an excuse to push the limits.
 
r/m

I have heard the Lycoming 10% overspeed limit. I can't remember if I saw it in writing. The reality is that in the aerobatic competetion world of the sixties until the era of the superplanes with six cylindedrs and constant speed props, MOST were turning 33-3500 r/m. Even the Eagles team retained fixed pitch props in order to make a lot of noise for airshows. The engines would go 1200 plus hours.
 
Propeller too!

My hartzell has a 10% overspeed limitation on it too.

But, with only 2730 rpm if you have the same 10% limitation that I am allowed it's seems you are ok there.
 
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