REFLECTOR:Incident/crash

[reflector@tvbf.org]

At 06:09 PM 5/23/03 -0500, you wrote:
>Mike,
>I was just going to post the same thing..... the dump should work perfectly,
>and in mine, the nose gear is down and locked before the mains, plus the
>airflow should help it also, so this is puzzling...... unless the nitrogen
>spring was dead, and unable to push the linkage over center, so the gear was
>down but not locked????????

I'm an outsider here (and grateful for your letting me hang out) but if you 
folks are using gas springs for gear overcenter springs, you should know 
about one of the failure modes.

We used gas springs for gear overcenter and canopies on the prototype 
Berkut, and when we talked to a rep from The Gas Spring Company (that was 
really their name) they specifically asked about using them in the gear, 
because that's what Lancair was doing.  It turns out that if a little chunk 
of seal breaks off inside the cylinder, it can get lodged in the orifice 
and totally lock a gas spring in both directions.

We ended up making cylinders with springs and plungers that worked 
basically the same way as a gas spring, but without the damping.  That 
failure mode is rare, but the rep had a picture of a car hood creased at 
the gas spring attach point, where someone had tried to force it down 
against a locked spring.  He said it was about a 1-1000 failure mode.

Just thought I'd let you know, I don't know if the Velocity design would 
still let you lower the gear with a locked gas spring in the system.