Mike,
I wasn't aware of the instances you noted below, so no argument. FWIW, I did have a vibration problem with my Neu setup, and it was because the aft support was loose.
For the firewall mounted outrunners, I am convinced the firewall needs to be very stiff, and if the firewall can be softened by heat from the heads of the mounting bolts, which allows the motor to become loose. Even a small amount of flex or looseness in the motor or mount can allow nasty vibration/resonance with either inrunners or outrunners.
I would note that the vast majority of electrics in recent years have run APC-E props, which makes it likely that any problems included the use of an APC-E prop (whether APC-E contributed to the problem or not). With increased use of CF props, it stands to reason that CF props will be associated with more problems in the future (whether the prop is the problem or not - and post mortem is quite difficult in most instances).
For the incidents you noted below, was APC contacted? APC has always been very proactive about researching/evaluating/understanding problems or potential problems, and in the past they have made improvements to props to resolve issues.
Regards,
Dave
ORIGINAL: mups53
Dave I know of 4 seperate cases this last season of motor ejections with both outrunners and inrunners. Dave Snow twice ejected and his last one was his brand new Neu inrunner. Chris Moon ejected a Pletty firewall mounted and we had another firewall mounted ejection from an AXI F3A at my field this year with Gary Stephens. All using an APC E.
My opinion is there is a correlation. Anyone is free to argue it but it's still my opinion that the E. props are too thin and too large for the stress and I'd advise using a CF prop or the APC's with the CF reinforcement. Who knows what side forces and turbulance situations happen in the air. I saw a video on violent worrble and its unbelievable what happens once it gets started. No mount or fuse could hold up to the stress.
Does anyone know the link to that video? Thanks, Mike