November 18th 08, 03:04 AM
posted to rec.aviation.piloting,alt.comp.freeware
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What happened to Jay?]
On Mon, 17 Nov 2008 18:20:33 -0800 (PST), Dudley Henriques wrote:
On Nov 18, 12:51*pm, Franklin see_REPLY-TO_header wrote:
On Tue 18 Nov08 06:59, Dudley Henriques wrote:
On Nov 18, 7:14*am, Franklin see_REPLY-TO_header wrote:
On Mon 17 Nov08 23:30, Dudley Henriques wrote
in news:60ccd111-02f8-4eae-bb7a-582816c86b45
@v22g2000pro.googlegroups.com:
On Nov 17, 10:23*am, Payton Byrd
wrote:
[...]
You missed the term "increasing" I'm afraid. 5.5 squared is 30.5,
which is fine for pure math, but not fine for a turning F14 with
a linear expanding g profile.
The 25 figure as stated in the assumption is correct within the
problem.
Fun isn't it?
Sir, please sir. The Ps value is far too low.
Good try but no cigar I'm afraid. No Ps value is possible for ANY
aircraft without the inclusion of altitude in the equation.
Ps can be positive or negative anywhere in the envelope not on the
Ps0 line for the aircraft, BUT establishing that Ps value in any
turn is directly related to the altitude where the turn parameters
are in play.
I see that now. Ok. My mistake.
I have no idea who you're trying to impress here, but you
unfortunately picked the wrong guy :-) The purpose of my work with
the Turkey was related to EM :-))
You asked a question. I thought I could answer it. I got it wrong but I'd
like another go!
You don't give altitude so I will assume it. *You made me re-examine
where I went wrong with Ps. And look up some F-14 specs. Specific excess
power Ps is delta energy with delta time. Accounting for induced drag
which the question focuses on then (assumming weight is approx 55 klbs)
at that state I say you would get acceleration.
Going over the various possibilities it seemed (not entirely sure) that
greater thrust should encounter even greater drag and so airspeed could
fall. *Am I getting closer?
If you want to talk energy maneuverability be my guest.
Dudley Henriques
That's for a John Boyd! What a maverick. I couldn't hope to match his
stunts to highlight E-M.
Sorry for my offensive post. Things have been nuts around here lately
with all these characters and I thought you might be another one :-)
Yes, your second try is exactly right. In the example given, if the g
is decreased the Turkey will accelerate which is the answer to the
first question, and if the g is increased, airspeed will fall victim
to drag.
Another way to present the "problem" would be as follows, only this
time including the altitude which as you have correctly surmised,
gives us a Ps figure for the F14. In our example, the Turkey is at T-
D=0 which = Ps=0 or on the Ps equals zero line for the F14.
An F14 at 420 KCAS, 15K, in a level turn at military. As the g is
increased, drag increases as it's square. At about 5.5g, induced drag
has increased by a factor of 25. At this point, T-D=0 and Ps=0. If g
is decreased the F14 will accelerate. If we pull harder, airspeed will
drop off.
Thank you for explaining your post instead of reacting to my over
aggressive response to you.
Dudley Henriques
Ben's a doll.
Really.
--
Meet Ari!
http://preview.tinyurl.com/3wh3hh
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