In article t,
"Dudley Henriques" writes:
Thanks much Pete. That's the exact quote I was getting on this, so this
has to be the training manual in question.
I asked around the P51 community a bit on this and have heard back from
Vlado Lenoch and Glenn Wegman. Neither mentioned the manual per se, but
not to my surprise, agreed with me that there are no basic issues in
slipping the 51 save doing it below 200 feet due to the quick and
sometimes unpredictable payoff behavior of the wing at low speed and
high angles of attack.

Thanks. Back when Don Davidson had his Mustang, he told me that he
had no problems at all with anything he wanted to do with it. (I know
- that's a somewhat loaded statement, but he's practice aerobatics
over my house, so it wasn't all straight and level.) The stability
and control derivitives from the NACA documents indicate that there
shouldn't be any problems, either.

When I was told about this being in this manual, I immediately dove into
my dusty old desk and dug out the old dash 1 for my airplane. Under
rudder control, it plainly states that sideslips are no issue at all,
and in fact mentions sideslips by name.
My take on the training manual is that pilots coming out of Advance in
the AT6 and transitioning into 51's during lead in fighter training were
faced with dealing with the laminar characteristics of the Mustang
coming off the comparatively higher lift characteristics of the T6,
which could be slipped like mad. I'm fairly certain, although I could
never prove this, that the Training Command thinking at the time was to
save lives and conserve sheet metal. The Mustang really doesn't need to
be slipped on final due to the extremely high drag of the last flap
position at 50 degrees (47 actually) plus running up the prop to low
pitch against the stops is like dragging your feet in the mud in this
airplane. My guess is that ATC just decided after looking at the log
books for total time of the guys transitioning into the Mustang that
having this restriction saved them a lot of trouble writing accident
reports, since it wasn't necessary to slip the airplane anyway.
The wording is interesting though, and I guess one could stretch a point
in justifying the restriction by noting control response degradation in
the left side of the Mustang's envelope.

That makes a lot of sense, from a Peacetime Air Force point of view.
I've heard similar tales about the F-86. Apparantly the Word Went
Down in ATC that F-86s couldn't be slipped, while pilots all over the
world were slipping them in on final.

About the military/civvie conversions;
Mine had the old radios and junk in it.
The military Mustang had a bunch of crap in it that more or less kept
the cg in limits. When the guys started gutting them and converting
them, they took a lot out and threw the cg forward enough that they
needed weight in the tail or at least had to be REAL careful landing
them. It wasn't uncommon to see full nose up pitch trim on some of them
after 3 pointing them.

To tell you the truth, that seems more than a bit dicey to me. Wasn't
anybody doing Weights & Balances on them? Throwing the CG out to make
room for more stuff sounds like a disaster in the making. Especially
if the pilot's new to the airplane, and new to high performance
airplanes in general.

I always landed the Mustang with some speed on the airplane, tail low on
the mains anyway, but the cg can be a problem for the pilots who like to
do 3 pointers in the airplane.

Oddly enough, the L-19 was the same way for me. I couldn't 3-point
the blasted thing for beans, but a tail-low wheeler was the most
comfortable.

I remember Vlado telling me something about Moonbeam's configuration,
but I forget if he has the cg issue. I would assume he does, as Collins,
Bendix, and King, are a whole lot lighter than that old crap we had in
there :-))
Dudley
I guess the bottom line on what the manual says would be;
Manual says "no slips"
Dash 1 says, "No slip restrictions"
I would say, "no problem at all, but not under 200 feet"
Other P51 pilots are checking in with "I do it"
Puzzling how the government does things isn't it? :-))))

I've seen worse.

--
Pete Stickney

Without data, all you have are opinions