"Gord Beaman" wrote in message
...
"Dudley Henriques" wrote:

The team was officially "reformed" on April 1st, 78 as the 431st ADS, but
this had absolutely nothing whatever to do with the Tutor. In fact, it
was
the existence of the toot that prompted Col Phillip to form the team
several
years earlier . I don't believe the team would ever have been formed had
the
toot not been available, as budget restraints have always been a problem.
Dudley Henriques

Yes, it does seem that I was in error having misinterpreted the
information on the Snowbirds' website (which was misleading imo)
I'll need to be more careful.

So that makes the score 'one for you' & 'what' for
me?...considerable in any case...


-Gord
"Are you trying to tell me that the
rotational (energy) of a propeller is
the same at 15 inches as it is at 61?"
-Guess who

Why yes, that's EXACTLY what I was trying to tell you, and I was as correct
then as I am now.
Any high school student knows that the rotational energy of a propeller is
directly tied to it's rpm and not it's manifold pressure. That wasn't the
context of what I saying at all, unless you have an agenda that requires you
to believe that....like you do apparently.
I'll go over it one more time so that you and anyone else who cares to
comment can do so.
The discussion where this came up was directly concerned with a bail out by
two people from a P51D where a snap roll caused by an engine seizure could
have been a factor in throwing the occupants from the cockpit.
Knowing the 51 as I do, I suggested if you remember, that the snap might not
have been caused by the seizure. I had a reason for suggesting this. The
24D50 Ham Standard on this airplane has a constant speed pitch range of 42
degrees. In a bail out preparation under stress assuming the prop set at
some degree of cruise and under normal aerodynamic load for that
configuration, the reduction of manifold pressure without changing the prop
setting would cause the prop to begin a pitch change to maintain RPM toward
full increase. You were absolutely correct when you said that manifold
pressure didn't control rotational velocity, but you failed to consider as I
had considered, the governor high RPM pitch limit for this propeller. It's
absolutely true that the rotational velocity of the prop will remain the
same at any RPM within it's constant speed range, but with the power brought
back to idle, it's entirely possible that the prop would exceed it's high
RPM pitch limiter on the governor and at that point the RPM would DECREASE.
It would be this decrease in RPM and NOT the decrease in manifold pressure
that would cause lesser forces in an engine seizure.
The post where you inserted yourself into the discussion about RPM and
manifold pressure wasn't a friendly insertion. In fact, it was a lot like
your insertion here about my flying with the Snowbirds. It was an obvious
implication that I am nothing less than a liar of the first order in the
Snowbird case, and that I needed a lecture from you on rotational velocity.
I believe your opening statement about the prop was "You do.......well I
don't!!!
If you remember, I did everything I could to avoid lecturing you back, since
I know your background is sound on these matters and you don't need a
lecture from me any more than I need one from you.
I tried subtlety to suggest we were dealing with a constant speed prop,
hoping you would finally get the hint about the governor, but you took this
to mean that since a fixed pitch propeller is the only prop that is DIRECTLY
linked to manifold pressure, and as such exhibits an increase and decrease
in rpm as the result of power change as opposed to the constant speed which
of course doesn't.......unless the governor limits are exceeded :-)
I had made your point for you. Sorry, that wasn't the case at all.
My point was valid then and it's valid now. FWIW, you also were correct as
far as you went with your explanation on momentum and constant speed props;
but I say again, in discussing RPM and a constant speed prop like the 24D50
on the Mustang, you must include the governor high RPM limit or the momentum
will INDEED change as power is reduced below this limit......just like a
fixed pitch propeller; and THIS was the scenario that was being discussed in
the P51 bailout situation, NOT that power controls momentum per se'. I would
close my remarks to you on this by telling you that there is always an area
on Usenet for misunderstanding to occur, and you very well might have
misunderstood what I was saying because I was not clear enough. If that was
the case, I apologize for creating that misunderstanding, and I sincerely
hope that this post clears the air on the matter.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/ CFI Retired
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