What Kind of Helmet is This? - Page 3

 

Who is this Dave guy?  I am The Lizard.


Thanks for providing the link above.  I found it interesting.

I hadn't realized that the dual-shaft arrangement was relatively recent.

With the Pinnacle Airlines thing, I wasn't so fascinated by the restart
failure as what led to the trouble.

I don't think that taking an empty transport jet and yanking it around at
2-3 positive g's really does any structural harm (bad behavior, but maybe
not terrible behavior).  I can forgive that.  But what amazed me is the
deliberate abuse of the jet engines and overheating them.  Those are
expensive pieces of hardware, and they are generally necessary to get you to
an airport.  That seems like very reckless behavior directed towards one's
employer.

 

Chuck Yeager writes in his autobiography about a test pilot who made a
forced landing at some podunk airport in the middle of no place. It
would have cost tens of thousands of dollars to ship the proper
equipment in by train to get it started again, so Yeager just flew a
Lear jet over there. He parked it in front of the test plane, locked the
brakes, and opened the throttle on the turbine. He figured that since it
was a turbofan, enough of the jet exhaust was fresh air that the test
plane's engine could breathe and light up. So that's what they did ...
and got both planes home safely and without making a fuss.


Well, it's more recent than the original single-shaft design, but I read
about it when I was in grade school.

--
Timberwoof <me at timberwoof dot com>
faq:  http://www.timberwoof.com/motorcycle/faq.shtml
Ten Steps to Fascism: http://www.guardian.co.uk/usa/story/0,,2064157,00.html

 te:


Dave lives in Marshall, Michigan and rides a Honda 600 Shadow. He owns
at least two cats and likes to fly airplanes and fantasizes about
skydiving with his cats.

You are Dave.


Gas turbine technology has come a long way since the centrifugal flow
J33 engine
had a compression ratio of only about 5 or 6 to 1. Axial flow
turbojets from the 1950's were lucky to have a compression ratio of
10:1.

That would provide about 147 psi going into the nozzles before the
combustor cans.

But the improved interstage sealing has made it possible for the
compressor to put
a lot more pressure into the cans, as well as bypass a lot of air
around them to cool the engine.

A while back I was discussing the subject with Bob Nixon,
alt.motorcycle.sportbike's resident technofreak and we figured out
that modern turbofan compressors must be putting several hundred
pounds of pressure to the
combustor cans and providing a lot of cooling air to the engine.

Nixon rides with airline pilots. You should post your aviation
comments to alt.motorcycle.sportbike

If that aircooled turbine engine suddenly stops turning, the hot
section loses cooling, and the tight clearances that improved engine
efficiency work against you and you get core lock.


Well, it looks to me like they tried to zoom climb to FL410, but
didn't know how to
do it correctly. They needed to be flying close to Mach 1 and then
pull up to convert speed into altitude.

Turbine compressors don't like sudden changes in AOA, they stall. That
might have caused the flame out...

 

Sigh...y'know, that was cute, MAYBE, the first time.


Bob M.

 
Seriously, my e-mail address is jujitsu.lizard@gmail.com.  Now, would Google
allow me to obtain that e-mail address if I wasn't a real lizard with some
training in Jujitsu?  Would they?  That is proof.

Furthermore, I don't have a picture of me handy, but this is my wife:

http://upload.wikimedia.org/wikipedia/commons/9/94/Plumed.basilisk.750pix.jpg

I remember the day we discussed sending her picture into Wikipedia.  I took
several photos and we chose the best one.

I think that is proof enough.

The Lizard