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How To Prevent Flutter And Other Aeroelastic Modes

Interesting article and the Youtube links. There was a recent post about a F1 Rocket that lost most of the horizontal stabilizer but the pilot managed to land it safely. Scary stuff.
 
The F1 Rocket that recently had the tail damage was above VNE however the failure appears to have been caused by a rapid G onset starting from a negative G value to above 8 G?s with a high onset rate. It does not appear to be flutter.
 
I have had a prop/engine whirl mode with my 7, IO360 M1B engine w/Hartzell composite prop. The spinner moves 1/4" off center. It has occurred at low rpm after a gentle bounce on the runway. Has anyone else had this occur in an RV?
 
Gust Loading

The F1 Rocket that recently had the tail damage was above VNE however the failure appears to have been caused by a rapid G onset starting from a negative G value to above 8 G?s with a high onset rate. It does not appear to be flutter.

You probably shouldn?t rule out turbulence/gust loading as a contributor either....
 
Nice briefing Carl! This thread should be a sticky just so guys can find that easier.
 
Carl,

The presentation, IMHO, is beyond excellent.

I benefited from 15+ years of mentoring by John Thorp. After his passing I contacted Martin Holman (noted flutter expert) to reinforce John's position as various "modifications" were being explored by T-18 builders that my personal exposure led me to conclude they were not consistent with John's position.

The push-back to my request to "think it over" was interpreted by many as "You have to do it my way" - even if I specifically stated otherwise.

This presentation is the most "together" survey I've come across and I thank you for bringing together the concepts and teaching me what (except in limited circles) usually isn't taught!

Thanks again!
 
I have had a prop/engine whirl mode with my 7, IO360 M1B engine w/Hartzell composite prop. The spinner moves 1/4" off center. It has occurred at low rpm after a gentle bounce on the runway. Has anyone else had this occur in an RV?

That's very interesting, Bill. I have an RV7 with the aluminum 7497 blended airfoil Hartzell and have never noticed mine do that.
 
I have had a prop/engine whirl mode with my 7, IO360 M1B engine w/Hartzell composite prop. The spinner moves 1/4" off center. It has occurred at low rpm after a gentle bounce on the runway. Has anyone else had this occur in an RV?

I would suspect your engine mount rubber isolation dampers. How old? What brand?
 
Super nice guy too!

On top of the excellent flutter presentation Carl is a super nice guy and took the time to go out of his way to welcome me to the RV community when I was visiting another RV guru Terry Burch ( super nice guy too ) in Arlington Washington before this dam border closure . This kind of self less giving is what makes aviation and especially the RV community so inviting and pleasurable Cheers. Stew
 
RV6 whirl mode on taxi

I have had a prop/engine whirl mode with my 7, IO360 M1B engine w/Hartzell composite prop. The spinner moves 1/4" off center. It has occurred at low rpm after a gentle bounce on the runway. Has anyone else had this occur in an RV?

I have an RV-6A and when I put on my WhirlWind GA-200L-72" I would get more than just a gentle bounce when taxiing around 1000-1100rpm! It got MUCH better after dynamic balancing, but then I actually decided to re-index my prop for a completely different reason and even without the dynamic balancing the problem seems to be completely gone. I can provide more details (best to email me: [email protected])
 
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