On Sun, 16 Dec 2007 17:48:24 -0600, "Eric" wrote:

If you want teeth rattling and the feeling that your heart is going to
vibrate though your chest, you should try a B-52G with all 8 burning water
(water injection for the uninitiated).

I never got to work on the SR-71, but their power runs were always awesome.
Your teeth rattled from a 1/2 mile away.

Well, I got 1/2 that with the old 707 water wagons. They phased them out just
as I started working at LAX. I wasn't sad to see the 707's go away, they were a
pain in the arse to work on... dirty, nasty and patches on top of patches.
Built like the proverbial brick outhouse and nearly bulletproof but I much
preferred working on the L-10's and 747's.

One of the worst jarring's I ever got was during a 767 engine runup. I was on
the headset, leaning against the fuse by the nose gear, half asleep. There was
an LST (Lead Systems Technician... a super trouble-shooter, as it were) and a
couple of mech's in the cockpit. #2 was already running and they were just
starting to spin #1 up when the N1 rotor simply froze. The wing and engine
flapped like a bird, the nose jumped a full 2 feet to the right and I amost got
dumped on my backside (it was 6 AM and I'd been there all night). I don't know
what the N1 %RPM was, I know it was low but still, I couldn't see individual
blades. I'd guess maybe 10% or so.

I'd never seen (or felt!) anything like it and just automatically assumed it was
an engine change, since we were working on the ETOPS program at the time
(Extended over water flight with a twin engine) and every time the airplane
farted, they changed something. I was pretty excited (not to mention wide
awake) and asked the LST what the hell had happened but he just asked if the
disk was turning now (it was, rotating slowly in the wind) and when I said yes,
he just started it up like nothing had happened. I was pretty well floored,
since even a compressor stall was cause for an engine change.

I talked to him later and he said "Oh, they do that now and then, the blades get
caught up in the sound baffle material." (which was a micarta stuff that got
chewed up as the blades grew). Basically, he just blew it off. Funny, I'd
never heard of it nor seen it, before or after. Take into account I'd just been
recalled after a 5 year lay off and a couple of years in Saudi Arabia and I'd
only just started working on the 767's. Still, it rattled me, certainly more
than the LST, anyway. The other guys said they'd never seen it before, either.
Oh well. The airplane flew off on it's morning flight and made it to London
without incident. Weird stuff, it was.
Cheers,
jc