Minumum Sink Rate/Best L/D at 17,000 feet ?

Andy wrote:


You'll need to define how height and altitude
are independent.



Height = AGL
Altitude = above MSL


Jack

On Apr 12, 8:26*am, Jack wrote:
Andy wrote:

* You'll need to define how height and altitude

are independent.

Height = AGL
Altitude = above MSL

Jack

My understanding is NO. Here's an example:

On the CRJ at 10,000 feet best L/D is 170 kias......then at the same
weight and ISA deviation and flap setting, stall speed at 41,000 feet
is 173. So if you pitched for best L/D for 10,000 at an altiude of
41,000 feet you would stall the airplane. I know this because I have
studied in great detail flight 3701. Those pilots just a few years
ago, stalled the crj at 41,000 feet at 173 knots. Then they glided
the 50 seat passenger jet into a neighborhood in the middle of the
night. The plane exploded and both pilots died. No passengers aboard
the flight. It was a reposition. Very sad day.

KIAS stall speed changes with altitude....so does L/D KIAS.

41,000 feet you would stall the airplane. *I know this because I have
studied in great detail flight 3701. *Those pilots just a few years
ago, stalled the crj at 41,000 feet at 173 knots. *Then they glided
the 50 seat passenger jet into a neighborhood in the middle of the
night. *The plane exploded and both pilots died. *No passengers aboard
the flight. *It was a reposition. *Very sad day.

KIAS stall speed changes with altitude....so does L/D KIAS.

I think you'll find that you are confusing KTAS and KIAS. The NTSB
investigation of Pinnacle Flight 3701 is he

http://www.ntsb.gov/Publictn/2007/AAR0701.pdf

See section 1.16.1.2, footnote 54, saying all airspeeds are in KCAS
(which is basically KIAS). Section 1.16.1.3 para gives the best L/D of
170 KCAS. It doesn't say anything at which altitude that was, because
L/D given in KCAS doesn't change with altitude.

I find that flying at 1,000 feet and 20,000 feet my glider will stall
at the same KIAS, you should try it yourself.