Any P51 experts out here?

[Dudley Henriques]

I'm researching something and can use some assistance if anyone has the
expertise or the inclination to be of assistance with this.
Apparently there was a training manual put out during the forties on the
P51 Mustang (not the airplane's dash 1 which totally contridicts this
manual) that said the 51 could NOT hold or maintain a slip.
I'm interested in any information on that manual, and/or the reasons for
this statement.
I already know the Mustang can be slipped as I've slipped it many times.
What I need is origin information on this exact training manual and any
reasoning for the no slip ability statement being in that manual.
Thank you
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/CFI Retired
for private email; make necessary changes between ( )
dhenriques(at)(delete all this)earthlink(dot)net

[Dudley Henriques]

Thanks much Pete. This training manual supposedly says that the 51 can't
hold a slip due to aileron or rudder issues that make it straighten out
if the pilot tries to hold it in a slip.
I've done hundreds of slips to both sides in this airplane and never had
such an issue. I'm assuming the training manual was written as an aid in
transitioning low time pilots into the high performance 51, as the dash
one specifically states that slips are not an issue.
The 51 does pay off fairly quickly on landing if you get it too deep
into the left side before touchdown and it can be a bit hairy. You
generally wouldn't hold a slip in the 51 under 200 agl for safety
reasons, and between the last flap position drag index and running the
prop up to low pitch, you really don't need slips in the 51, but I'm
really interested in researching the obvious conflict between the
training manual, the dash1, and my own personal experience in the
airplane along with every other 51 driver I have asked about this.
Thanks much for the help. I'll watch the thread for you.
Dudley
"Peter Stickney" > wrote in message
...
> In article t>,
> "Dudley Henriques" > writes:
>> I'm researching something and can use some assistance if anyone has
>> the
>> expertise or the inclination to be of assistance with this.
>> Apparently there was a training manual put out during the forties on
>> the
>> P51 Mustang (not the airplane's dash 1 which totally contridicts this
>> manual) that said the 51 could NOT hold or maintain a slip.
>> I'm interested in any information on that manual, and/or the reasons
>> for
>> this statement.
>> I already know the Mustang can be slipped as I've slipped it many
>> times.
>> What I need is origin information on this exact training manual and
>> any
>> reasoning for the no slip ability statement being in that manual.
>> Thank you
>
> Wait one, Dudley. Somewhere down here in the office I've got an F-51
> Training Manual. I'll dig it out Tomorrow Morning, and let you know.
>
> --
> Pete Stickney
>
> Without data, all you have are opinions

[Peter Stickney]

In article t>,
"Dudley Henriques" > writes:
> I'm researching something and can use some assistance if anyone has the
> expertise or the inclination to be of assistance with this.
> Apparently there was a training manual put out during the forties on the
> P51 Mustang (not the airplane's dash 1 which totally contridicts this
> manual) that said the 51 could NOT hold or maintain a slip.
> I'm interested in any information on that manual, and/or the reasons for
> this statement.
> I already know the Mustang can be slipped as I've slipped it many times.
> What I need is origin information on this exact training manual and any
> reasoning for the no slip ability statement being in that manual.
> Thank you

Wait one, Dudley. Somewhere down here in the office I've got an F-51
Training Manual. I'll dig it out Tomorrow Morning, and let you know.

--
Pete Stickney

Without data, all you have are opinions

[John Miller]

Dudley Henriques wrote:
> Thanks much Pete. This training manual supposedly says that the 51 can't
> hold a slip due to aileron or rudder issues that make it straighten out
> if the pilot tries to hold it in a slip.
> I've done hundreds of slips to both sides in this airplane and never had
> such an issue. I'm assuming the training manual was written as an aid in
> transitioning low time pilots into the high performance 51, as the dash
> one specifically states that slips are not an issue.

Just guessing here -- if a slip (in the P51) approaches a stall, is its
behavior particularly treacherous?

--
John Miller
email domain: n4vu.com; username: jsm(@)
Surplus (For sale or trade):
New Conn V1 double trumpet case, no logo
Tektronix 465B oscilloscope
New Fellowes leather brief/notebook case

[Dudley Henriques]

"John Miller" > wrote in message
...
> Dudley Henriques wrote:
>> Thanks much Pete. This training manual supposedly says that the 51
>> can't hold a slip due to aileron or rudder issues that make it
>> straighten out if the pilot tries to hold it in a slip.
>> I've done hundreds of slips to both sides in this airplane and never
>> had such an issue. I'm assuming the training manual was written as an
>> aid in transitioning low time pilots into the high performance 51, as
>> the dash one specifically states that slips are not an issue.
>
> Just guessing here -- if a slip (in the P51) approaches a stall, is
> its behavior particularly treacherous?

Any aircraft, whether in a slip or not, that approaches it's critical
angle of attack (stall) can be dangerous if close to the ground. Slips
are not done at AOA close to stall. AOA is controlled in a slip by pitch
the same way it is in non cross controlled flight. The Mustang, having a
laminar wing can stall more quickly than say an aircraft with a higher
cambered wing.
To eliminate pilots bending the sheet metal, it is usually recommended
that slips in the 51 end at or above 200 feet AGL.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/CFI Retired
for private email; make necessary changes between ( )
dhenriques(at)(delete all this)earthlink(dot)net

[John Miller]

Dudley Henriques wrote:
> The Mustang, having a
> laminar wing can stall more quickly than say an aircraft with a higher
> cambered wing.
> To eliminate pilots bending the sheet metal, it is usually recommended
> that slips in the 51 end at or above 200 feet AGL.

That was kind of my question, which I probably phrased poorly, that is,
wouldn't the laminar wing give significantly less warning pre-departure
compared with, oh, say, a Stearman, which lots of the WWII guys learned
to slip in? I believe you said that you'd done slips in a Mustang,
which shows it *can* be slipped, and suggests that the warning may be
more cautionary than indicative of a technical difficulty.

Best regards,
--
John Miller, who doesn't like to do slips in ANY aircraft below 200'
AGL, actually...

[Dudley Henriques]

"John Miller" > wrote in message
...
> Dudley Henriques wrote:
>> The Mustang, having a
>> laminar wing can stall more quickly than say an aircraft with a
>> higher cambered wing.
>> To eliminate pilots bending the sheet metal, it is usually
>> recommended that slips in the 51 end at or above 200 feet AGL.
>
> That was kind of my question, which I probably phrased poorly, that
> is, wouldn't the laminar wing give significantly less warning
> pre-departure compared with, oh, say, a Stearman, which lots of the
> WWII guys learned to slip in? I believe you said that you'd done
> slips in a Mustang, which shows it *can* be slipped, and suggests that
> the warning may be more cautionary than indicative of a technical
> difficulty.
>
> Best regards,
> --
> John Miller, who doesn't like to do slips in ANY aircraft below 200'
> AGL, actually...

You are correct about the Stearman/ Mustang comparison. The 51 is best
put on the mains tail low, at least that has always been my
recommendation and practice.
I agree about the training manual, and expect that is what will be
discovered as I research this a bit more.
DH

[Dudley Henriques]

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.
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.

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.
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.
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? :-))))
Dudley


"Peter Stickney" > wrote in message
...
> In article t>,
> "Dudley Henriques" > writes:
>> Thanks much Pete. This training manual supposedly says that the 51
>> can't
>> hold a slip due to aileron or rudder issues that make it straighten
>> out
>> if the pilot tries to hold it in a slip.
>> I've done hundreds of slips to both sides in this airplane and never
>> had
>> such an issue. I'm assuming the training manual was written as an aid
>> in
>> transitioning low time pilots into the high performance 51, as the
>> dash
>> one specifically states that slips are not an issue.
>> The 51 does pay off fairly quickly on landing if you get it too deep
>> into the left side before touchdown and it can be a bit hairy. You
>> generally wouldn't hold a slip in the 51 under 200 agl for safety
>> reasons, and between the last flap position drag index and running
>> the
>> prop up to low pitch, you really don't need slips in the 51, but I'm
>> really interested in researching the obvious conflict between the
>> training manual, the dash1, and my own personal experience in the
>> airplane along with every other 51 driver I have asked about this.
>> Thanks much for the help. I'll watch the thread for you.
>
> Dudley,
> Here's what I have. From AAF Manual 51-127-5, "Pilot Training Manual
> for the P-51 Mustang", 15 August 1945.
>
> Page 66:
> "The P-51 does not hold a sustained sideslip. The aileron control is
> not sufficient to hold the airplane in a sideslipping angle. However,
> you can sideslip it long enough to avaid enemy fire in combat. When
> any sideslipping is attempted, be sure to recover completely above 200
> feet."
>
> In truth, that sounds a bit fishy to me, as well. Of late, I've been
> wading through the incredible amount of Tech Reports that have been
> made available on the NACA Tech Reports Server. (About 10,000
> inindexed
> files. I'm not complaining. Indexing them is a huge effort, and I
> _like_ roaming through huge reams of extreme Aero-Geekery. Color me
> strange.) Among them are the reports on the wind tunnel test series
> that were run to prove out the extended fin used on the P-51H (And the
> Temco TF-51Ds from the 1950s, and the Cavalier '51s). They show that
> for the P-51D configuration, with the great big long nose, the
> direction stability's a bit weak at low speeds. (Not bad, mind, but
> they wanted it better) Even though the '-51's ailerons get a bit
> mushy
> when slow, that ahouldn't have been a problem.
>
> I've also got a copy of the report of the modern-era flight tests
> comparing the F6F, P-51, P-47, and F4U by John Ellis and Chris Wheal
> that were published in _Cockpit_. (The journal of teh Society of
> Experimental Test Pilots)
>
> I regards to sideslip behaviour, they make this comment:
> "Steady heading sideslips in cruise and land configurations revealed
> nothing out of teh ordinary beyond the fact that the rudder forces in
> both the Hellcat and Corsair were extremely high. Full rudder
> sideslips generally required 50-60% of available aileron deflection in
> cruise at 180-190 kts, and 20-50% aileron in the landing
> configuration."
> That doesn't sound like it can't sideslip to me.
>
> There is one thing in the _Cockpit_ article that I find a bit odd.
> They rate the P-51 as being rather heavy in pitch. According to their
> data, they measured 'bout 20 lbs/G. That doesn't seem right to me -
> from other data, I'd have thought that about 6 lbs/G would have been
> more like it. Now, I know that late-model P-51Ds had bobweights in
> the pitch system to help counteract the really light forces that you
> got with an extremely aft CG, such as when the fuselage tank was
> installed & filled. Would having the bobwights in the airplane with a
> forward CG heavy things up to that extent? Or could hte airplane have
> been out of rig? (If it helps, the P-51D they used for the tests was
> N51HT, Harry Tope's airplane.
>
>
> --
> Pete Stickney
>
> Without data, all you have are opinions

[Peter Stickney]

In article t>,
"Dudley Henriques" > writes:
> Thanks much Pete. This training manual supposedly says that the 51 can't
> hold a slip due to aileron or rudder issues that make it straighten out
> if the pilot tries to hold it in a slip.
> I've done hundreds of slips to both sides in this airplane and never had
> such an issue. I'm assuming the training manual was written as an aid in
> transitioning low time pilots into the high performance 51, as the dash
> one specifically states that slips are not an issue.
> The 51 does pay off fairly quickly on landing if you get it too deep
> into the left side before touchdown and it can be a bit hairy. You
> generally wouldn't hold a slip in the 51 under 200 agl for safety
> reasons, and between the last flap position drag index and running the
> prop up to low pitch, you really don't need slips in the 51, but I'm
> really interested in researching the obvious conflict between the
> training manual, the dash1, and my own personal experience in the
> airplane along with every other 51 driver I have asked about this.
> Thanks much for the help. I'll watch the thread for you.

Dudley,
Here's what I have. From AAF Manual 51-127-5, "Pilot Training Manual
for the P-51 Mustang", 15 August 1945.

Page 66:
"The P-51 does not hold a sustained sideslip. The aileron control is
not sufficient to hold the airplane in a sideslipping angle. However,
you can sideslip it long enough to avaid enemy fire in combat. When
any sideslipping is attempted, be sure to recover completely above 200
feet."

In truth, that sounds a bit fishy to me, as well. Of late, I've been
wading through the incredible amount of Tech Reports that have been
made available on the NACA Tech Reports Server. (About 10,000 inindexed
files. I'm not complaining. Indexing them is a huge effort, and I
_like_ roaming through huge reams of extreme Aero-Geekery. Color me
strange.) Among them are the reports on the wind tunnel test series
that were run to prove out the extended fin used on the P-51H (And the
Temco TF-51Ds from the 1950s, and the Cavalier '51s). They show that
for the P-51D configuration, with the great big long nose, the
direction stability's a bit weak at low speeds. (Not bad, mind, but
they wanted it better) Even though the '-51's ailerons get a bit mushy
when slow, that ahouldn't have been a problem.

I've also got a copy of the report of the modern-era flight tests
comparing the F6F, P-51, P-47, and F4U by John Ellis and Chris Wheal
that were published in _Cockpit_. (The journal of teh Society of
Experimental Test Pilots)

I regards to sideslip behaviour, they make this comment:
"Steady heading sideslips in cruise and land configurations revealed
nothing out of teh ordinary beyond the fact that the rudder forces in
both the Hellcat and Corsair were extremely high. Full rudder
sideslips generally required 50-60% of available aileron deflection in
cruise at 180-190 kts, and 20-50% aileron in the landing
configuration."
That doesn't sound like it can't sideslip to me.

There is one thing in the _Cockpit_ article that I find a bit odd.
They rate the P-51 as being rather heavy in pitch. According to their
data, they measured 'bout 20 lbs/G. That doesn't seem right to me -
from other data, I'd have thought that about 6 lbs/G would have been
more like it. Now, I know that late-model P-51Ds had bobweights in
the pitch system to help counteract the really light forces that you
got with an extremely aft CG, such as when the fuselage tank was
installed & filled. Would having the bobwights in the airplane with a
forward CG heavy things up to that extent? Or could hte airplane have
been out of rig? (If it helps, the P-51D they used for the tests was
N51HT, Harry Tope's airplane.


--
Pete Stickney

Without data, all you have are opinions

[Dudley Henriques]

"Peter Stickney" > wrote in message
...
> In article >,
> "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.

My thoughts exactly.
>
>> 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.

North American actually sent Hoover out to the groups to show the guys
what they could do with the F86. Then they sent him out again in the
F100 to do the same thing. The guys were blowing tires on landings.
Bob slipped and skidded the damn things all over the sky. When he was
finished, everyone knew what could and couldn't be done in these
airplanes. :-))
I think the only airplane Bob hasn't done these one wheel landings in
was the day I loaned him Miss America at Transpo when his 51 was down
after a gear malfunction. Howie asked me to ask Bob NOT to one wheel
Miss A, as we thought it placed a possible side load on the main strut
and Howie had to pay for the maintainence as opposed to Rockwell footing
any bills for Bob stressing a strut once in a while :-))
>
>> 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.

Actually, the problem was taking the stuff out!!! It threw the cg
FORWARD. The guys were putting weights in the tails to get the moments
in the right place. The civilian conversions were LIGHTER than the
military airplane. If you flew a civilian Mustang, the landing behavior
was different. You could be feeding in a lot of back trim on final with
all that weight out of there. :-))
>
>> 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.

Putting that little bird down on the mains with that spring gear had
it's moments that's for sure :-))
>
>> 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.

Thanks loads for taking the time for this info. Knowing where it came
from is a lot of help.
Dudley

[Peter Stickney]

In article >,
"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

[BOB'S YOUR UNCLE]

Did the Navy ever have P-51's in its inventory?


"Dudley Henriques" > wrote in message
nk.net...
> I'm researching something and can use some assistance if anyone has the
> expertise or the inclination to be of assistance with this.
> Apparently there was a training manual put out during the forties on the
> P51 Mustang (not the airplane's dash 1 which totally contridicts this
> manual) that said the 51 could NOT hold or maintain a slip.
> I'm interested in any information on that manual, and/or the reasons for
> this statement.
> I already know the Mustang can be slipped as I've slipped it many times.
> What I need is origin information on this exact training manual and any
> reasoning for the no slip ability statement being in that manual.
> Thank you
> Dudley Henriques
> International Fighter Pilots Fellowship
> Commercial Pilot/CFI Retired
> for private email; make necessary changes between ( )
> dhenriques(at)(delete all this)earthlink(dot)net
>
>

[Don McIntyre]

Dudley,
Let me start out by saying that I'm not a pilot and have never flown
anything with more power than a T-34A (flown from the backseat with a
"real pilot" up front) and a P-3 from the right seat.
Would the sideslip issue have been affected by the addition of the
fairing forward of the vertical stab? IIRC the P-51B/Cs didn't need the
fairing because of the extra side area they had compared to the
D-model. The early D-models apparently did have directional stability
issues prior to addition of the fairing. Maybe the training manual came
out before it was added?
Don McIntyre
Clarksville, TN

[Dudley Henriques]

"Don McIntyre" > wrote in message
oups.com...
> Dudley,
> Let me start out by saying that I'm not a pilot and have never flown
> anything with more power than a T-34A (flown from the backseat with a
> "real pilot" up front) and a P-3 from the right seat.
> Would the sideslip issue have been affected by the addition of the
> fairing forward of the vertical stab? IIRC the P-51B/Cs didn't need
> the
> fairing because of the extra side area they had compared to the
> D-model. The early D-models apparently did have directional stability
> issues prior to addition of the fairing. Maybe the training manual
> came
> out before it was added?
> Don McIntyre
> Clarksville, TN

That's an astute observation and is correct about the airplane. The post
block 10 D's did have a dorsal added for improved directional stability.
It's always been my understanding that this was due to airflow issues
coming off the bubble canopy changeover, but I ran into a NA engineer
some time ago who said it was also related to the fuselage tank
installation. I didn't have the fuselage tank in my airplane so that was
never an issue for me anyway.
It's interesting what you have brought up about the training manual.
It's dating is August 45.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/CFI Retired
for private email; make necessary changes between ( )
dhenriques(at)(delete all this)earthlink(dot)net

[Peter Stickney]

In article >,
"BOB'S YOUR UNCLE" > writes:
> Did the Navy ever have P-51's in its inventory?

They tested them several times, including a set of Carrier Trials
aboard the U.S.S. Shagri-La (CV-31) in November adn December 1944.

--
Pete Stickney

Without data, all you have are opinions

[Don McIntyre]

Dudley,
I don't quite understand how the fuel tank installation relates to
the dorsal fairing. Wasn't the fuel tank related to the "ass-heavy" CG
on the B-model (or did that also apply to the D)? The airflow off the
canopy makes a lot more sense to me.
I'm not trying to pick nits here, just curiousity has reared it's
ugly head. 8-)

Don McIntyre
Clarksville, TN

[Dudley Henriques]

"Don McIntyre" > wrote in message
oups.com...
> Dudley,
> I don't quite understand how the fuel tank installation relates to
> the dorsal fairing. Wasn't the fuel tank related to the "ass-heavy" CG
> on the B-model (or did that also apply to the D)? The airflow off the
> canopy makes a lot more sense to me.
> I'm not trying to pick nits here, just curiousity has reared it's
> ugly head. 8-)

I wouldn't disagree with this . Just mentioned it because it was a NA
engineer who threw it out there to us at one time.
In my opinion it was the canopy change that necessitated the need for
the dorsal extension. I remember questioning him at the time as well.
Dudley

[Jim Carriere]

Dudley Henriques wrote:
> "Don McIntyre" > wrote in message
> oups.com...
>
>>Dudley,
>> I don't quite understand how the fuel tank installation relates to
>>the dorsal fairing. Wasn't the fuel tank related to the "ass-heavy" CG
>>on the B-model (or did that also apply to the D)? The airflow off the
>>canopy makes a lot more sense to me.
>> I'm not trying to pick nits here, just curiousity has reared it's
>>ugly head. 8-)
>
>
> I wouldn't disagree with this . Just mentioned it because it was a NA
> engineer who threw it out there to us at one time.
> In my opinion it was the canopy change that necessitated the need for
> the dorsal extension. I remember questioning him at the time as well.

It sort of makes sense. The "ass-heavy" :) rear fuel tank take away
stability, the dorsal fairing contributes to stability. The bubble
canopy upset the airflow behind it and in front of the fin, the
dorsal fairing may have improved this.

So the question is whether the dorsal fairing was added for the first
reason, the second, or both. The airplane may be too old a design to
get a definitive answer, but I wouldn't be surprised if they added
the fairing for both reasons.

[Peter Stickney]

In article >,
Jim Carriere > writes:
> Dudley Henriques wrote:
>> "Don McIntyre" > wrote in message
>> oups.com...
>>
>>>Dudley,
>>> I don't quite understand how the fuel tank installation relates to
>>>the dorsal fairing. Wasn't the fuel tank related to the "ass-heavy" CG
>>>on the B-model (or did that also apply to the D)? The airflow off the
>>>canopy makes a lot more sense to me.
>>> I'm not trying to pick nits here, just curiousity has reared it's
>>>ugly head. 8-)
>>
>>
>> I wouldn't disagree with this . Just mentioned it because it was a NA
>> engineer who threw it out there to us at one time.
>> In my opinion it was the canopy change that necessitated the need for
>> the dorsal extension. I remember questioning him at the time as well.
>
> It sort of makes sense. The "ass-heavy" :) rear fuel tank take away
> stability, the dorsal fairing contributes to stability. The bubble
> canopy upset the airflow behind it and in front of the fin, the
> dorsal fairing may have improved this.
>
> So the question is whether the dorsal fairing was added for the first
> reason, the second, or both. The airplane may be too old a design to
> get a definitive answer, but I wouldn't be surprised if they added
> the fairing for both reasons.

The directional stability of an airplane depends, basically, on where
you put it's side area - area ahead of the CG is destabilizing, and
area behind it adds to the stability. When they cut down the aft
fuselage of the P-51 to put the bubble canopy on hte "D" models, they
lost some ditectional stability. (Yaw) The added the dorsal extention
to the rudder to try to remedy this, and in the later H-models and the
Temco and Cavalier builds put a taller fin on the airplane.

The data for this still exists. Buried in the uncatalogued files on
the NACA Technical Reports Server are the results of the wind tunnel
tests used to determine the H-models fin shape. It's also got the
stock D-model data in the report.

Note that the P-51 wasn't the only airplane theat needed its
directional stability punched up a bit after getting the bubble
canopy. A dorsal fin was added to late model P-47Ds, Ms, and Ns, and
the Spitfire got a brand new fin & rudder.

The fuselage auxilliary tank moved the CG aft, right to, or perhaps a
bit beyond, the practical limit for an aft CG. This had a small
effect of directional stability, but a huge effect on pitch
(longitudinal) stability. The airplane tended to be unstable in
pitch, very, very light on the stick at low Gs (Something like 1.5
lbs/G have been reported) and with a felt force reversal somewhere
around 4 Gs. This led to NAA and the USAAF devising a bobweight
system in the elevator circuit that increased the feel of the airplane
in pitch.

--
Pete Stickney

Without data, all you have are opinions