3 G pull numbers.

[agent 009]

Found these numbers for 47 & Mustang. How bout Spit 9 & 109 G-10?

Your figures are remarkably accurate. I have data that indicates that the
P-51D, at corner speed, measures 48 lbs in a 3g pull. Up to 86 Lbs at
5g's. The P-47D, OTOH, requires just 16 lbs at 3g and 27 lbs at 5g's.
The testers state that the Mustang was a true "two hander".

[agent 009]

OK, any mark of 109 & any mark of Spit. Heck throw in 38 & 39 if anyone's got any data.

[Kurfürst]

Have you got a reference, I'd love the read more on this.

I have some elev deflection/stickforce data on the 109G, but unfortunately I dont think such data alone it would help much to arrive at stickforce/G... one curious thing is that it's reletively less sensitive to high mach numbers.

[agent 009]

Hi Kurfurst. Um, well all I have is the article-site it came from. Will post it.

The P51 (C.C. Jordan; CDB100620)  
... Subject: Re: P38 vs P-51 vs 109 vs 190 (was Re: Lindbergh in a Mustang Over Date: 8 ... test flight program >with the Mustang such as done by the EAA ...
yarchive.net/mil/p51.html - 12k - Cached - More from this site - Save - Block

[agent 009]

--------------------------------------------------------------------------------
Here is 1st half of article. site wouldn't allow whole thing.



From: cdb100620@aol.com (CDB100620)
Subject: Re: P-51 bob weights and rudder tabs
Date: 16 Sep 1997
Newsgroups: soc.history.war.world-war-ii

The Merlin P-51 had a lot of teething problems, but, for some reason, they
are largely overlooked.  It had problems with the canopy frosting over,
with jamming guns, with the engine cooling system and the engine
itself--and with shedding the tail.  In fact, the plane had so many
problems initially that Col. Don Blakeslee, CO of the 4FG, called it "an
experimental aircraft" and expressed doubts that it could be successful.
The P-38 had gone through its teething troubles the previous fall and with
the introduction into ETO combat of the J model well-pleased its pilots.
FGs getting the P-51 were unhappy and pilots grumbled that they would
rather have the Lockheed.  It was not uncommon to have almost 30 percent of
P-51 sorties aborted for mechanical reasons during the winter and spring of
1944 (typical abort rate for all causes for all USAAF aircraft was 8 percent).
When the D model became available in quantity in the summer, cases of the
aircraft losing its tail surfaces in flight began to be reported.  Flight
restrictions were placed on the aircraft and the tail surfaces were beefed
up.  Wing failures were also reported due to control stick force reversal
in high-speed dives.  The bobweight was added to the elevator control
system to fix this problem.  But for the aircraft to be even marginally
stable, the fuselage fuel tank had to be less than half full.
The Mustang still had problems a year later when the 7AF began B-29 escort
missions to Japan.  Incidences were reported of tail surface failures in
dogfights. In one instance in April, 1945, a P-51D got into a dogfight with
a Mitsubishi Raiden.  During the violent maneuvering, the Mustang first
shed its tail control surfaces and then its wings were torn off.  The
pilot, 2Lt. James Beattie, did not get out.  The Raiden apparently suffered
no damage from the severe loads placed on it during the dogfight.

All that said, the Merlin Mustang was a very effective fighter, but its
greatest successes came in the ETO, where its high abort rate would not
result in equally high pilot fatalities.  Over the vast reaches of the
Pacific, the P-38 was the fighter of choice.  Mustangs suffered their
greatest operational loss of the war on an escort mission to Japan when 27
out of a force of 148 went down.  Most of the losse were weather-related
(always a greater danger than the enemy in those days) rather than
mechanical failures, but the Mustang seemed dogged by bad luck and had
little success battling Japanese fighters over the home islands.  The
contrast with its sweeping victories over the Luftwaffe is striking.
P-38 pilots relate the story of an apparently new-in-theater pilot who
called over the radio, "Mayday!  I've been hit and am losing coolant.  What
should I do."  To which a P-38 pilot replied, "Calm down.  Just feather the
prop and trim for single-engine flight and you'll get home okay."  There is
a long pause, and then the first pilot says, "Feather it, hell!  I'm in a P-51."
Mustang pilots in the PTO sang a ditty that went:

"Don't give me a P-51.
It was all right for fighting the Hun,
But if fighting the Jap you try,
You'll run out of sky.
Don't give me a P-51."

(The reference to "running out of sky" refers to the great amount of
altitude lost in dogfighting the maneverable Japanese fighters.)

In contrast, they sang about the Lightning:

"The P-38 is some machine,
The answer to a flyer's dream.
She'll dive, loop and climb
And turn on a dime.
To every pilot,  she's the queen."

It's interesting  that these two ditties imply that pilots thought the
P-38 was more maneuverable than the P-51.  It could be that they simply
trusted the Lockheed not to come apart during violent  maneuvers, and were
leery of pushing  the North American fighter.  It's even more interesting
that in the MTO and the ETO, apparently, P-38 pilots were a little afraid
of their mounts and hesitated to dogfight Luftwaffe fighters.  Go figure.

[agent 009]

Search for Google's copy of this article
--------------------------------------------------------------------------------

From: cdb100620@aol.com (CDB100620)
Subject: re: p-40
Date: 26 Sep 1997
Newsgroups: alt.history.what-if

>Wasn't the p-40 the design upon which the later p-51 was based?
>

The P-40 was the starting point for the P-51 design:  North American set
out to design a fighter with superior performance than the P-40 that would
use the same engine (Allison V-1710) and be more or less the same size.
The prompt was a British Purchasing Commission request for North American
to build P-40s under license, as it wanted to order more of them than
Curtiss could build.   Britishers often say that the Mustang was built to
British specifications. That's oversimplifying.  The design was essentially
North American's, but the BPC did specify that NA buy the wind tunnel and
flight test reports of the Curtiss XP-46 fighter to be used to help develop
the NA fighter.  NA engineers claim that although the company acquired this
material, it was not used in the development of the P-51.
The P-51 design used a boundary layer gutter that separated the cooling
air intake from the fuselage, preventing the intake from ingesting the
boundary layer (the layer of turbulent air close to the skin of the plane.
It was a brilliant idea, and folks are still squabbling over who suggested
the idea.  Some say it was Irving Ashkenas, an NAA aerodynamics engineer.
(He is also credited with moving the radiator air duct from the nose to the
belly of the plane.)  Others say D.B. Shenstone, a Rolls-Royce engineer,
suggested it.
The P-51 also used a laminar flow wing, which greatly reduced drag.  The
wing design was based on work done by NACA (predecessor of NASA).  The
square wingtips were based on pre-war work done by German researchers (Bf
109 had square wingtips).  The laminar wing greatly reduced drag, but it
gave no warning of an impending stall, making the airplane a tricky one to fly.
It was British input that replaced the Allison engine with a Merlin.  The
Allison was a smoother engine than the Merlin, but it only had a
single-stage, single-speed mechanical supercharger, thus limiting engine
performance at altitude.  The Merlin version put in the P-51 had a
two-stage, two-speed mechanical supercharger, which allowed the engine to
perform well to high altitudes.
The shift from first to second speed in the first stage of the
supercharger was barely noticeably, a mild kick at about 8,000 ft., sort of
like downshifting your car from 4th to 3rd at 30 mph.  But the shift from
the first stage to the second stage of the supercharger, which occurred at
about 17,000 feet, was an abrupt lurch, like downshifting your car from 4th
to 3rd at 60 mph.  Sometimes the supercharger would hang up and not shift
when it should, which could be a real problem in combat.
The best solution to high-altitude performance in a piston engine was the
exhaust-gas-driven turbo-supercharger such as was used in the P-38 and P-47
(plus the bombers and transport aircraft, including postwar piston jobs
like the Constellation and DC-6).  It maintained sea level horsepower right
up to 35,000 ft. and more.  But it took up a lot of space and I doubt the
P-51 had room for it.  Then again, the XP-37 variant of the P-40 airframe
was equipped with a turbo-supercharger.  It was mounted under the engine.
And the P-39, a smaller plane than the P-51, was originally equipped with a
turbo-supercharger.  The go-ahead to equip the P-51 with the Merlin may
have been a logistical one.  Packard had built a factory to produce Merlin
engines and there was no airplane to put them in.  The Allison was being
used by the  P-38, P-39 and P-40, and GE was at capacity producing
turbo-superchargers, so the suggestion to put the Packard-built Merlin with
its associated mechanical supercharger into the Mustang, where it fit
neatly with no major re-engineering needed, must have been a very welcome
one merely from a production point of view.  The boost in performance the
Merlin gave the Mustang was an unlooked for plus.

The P-40F was equipped with a Packard Merlin, mainly because of a shortage
of Allisons.  It's performance was about the same as Allison-powered P-40s,
suggesting that the airframe was the limiting factor in improving the
Curtiss fighter's performance.  That the P-51's performance jumped so much
when the Merlin was installed is an indication of just how advanced its
airframe was.



Search for Google's copy of this article
--------------------------------------------------------------------------------

From: C.C.Jordan@Worldnet.att.net (C.C. Jordan)
Newsgroups: rec.aviation.military
Subject: Re: P38 vs P-51 vs 109 vs 190 (was Re: Lindbergh in a Mustang Over
Date: 8 Dec 1998 23:58:22 GMT

On 8 Dec 1998 06:07:50 GMT, mlenoch@aol.com (MLenoch) wrote:

>Carlo asks:
>
>> maximum control input speed,
>
>>BTW what is this speed for the P-51D ?
>
>This speed is approximately near the cornering speed of 270 kts/ 310 mph.  Now
>granted, cornering speed allows maximum  turn performance; it not a structuraly
>safe speed for max turn performance COMBINED with maximum roll performance.  To
>put in max pull plus max roll would probably damage the wings.  (I understand
>that the F-16 has a flight control computer that limits max roll against max
>pull and vica- versa to prevent exceeding the wing loads due to control
>inputs).
>
>
>>BTW what are the control forces like at 200 kt, 250 kt, 300 kt etc in
>>the P-51 ?
>
>I dont have numbers to quote this. I would enjoy doing a test flight program
>with the Mustang such as done by the EAA for some of the homebuilt aircraft as
>flown usually by Dave Moruss(sp?).
>
>My guesses are:
>
>             full  aileron    3G pull
>200kt     20 lb                  20 lb
>250kt     25 lb                  30 lb
>300kt      ? high!              45 lb
>
>These numbers would be interesting to research and verify.
>
>V. Lenoch


& here is part 2.


Your figures are remarkably accurate. I have data that indicates that the
P-51D, at corner speed, measures 48 lbs in a 3g pull. Up to 86 Lbs at
5g's. The P-47D, OTOH, requires just 16 lbs at 3g and 27 lbs at 5g's.
The testers state that the Mustang was a true "two hander".

My regards,
C.C. Jordan

Now online - The P-38: Was its size and shape a disadvantage?
http://home.att.net/~C.C.Jordan/index.html
http://www.geocities.com/pentagon/quarters/9485/index.html
The "Planes and Pilots of WWII" website.
An online WWII aviation history magazine.
A member of the WWII Web-ring.
Honor and remember the WWII vets.

"In reality, there exists only fact and fiction. Opinions result from
a lack of the former and a reliance on the latter."

Search for Google's copy of this article

[Kurfürst]

Thanks a lot !

[agent 009]

No prob. Mustang a bit overrated I have always maintained. very good plane, but not without probs like any fighter. Sucky angle of climb & I met a Stang pilot in Idaho who said he didn't like forward view on the sides, distorted cause of rounded corners.

[Squire]

Full of historical innaccuaracies, and obviously written by a rabid P-38 fanboy.

All it is is an opinion from the internet, I can get you quotes of guys claiming they saw bigfoot if you like...

I say that as somebody who likes neither the P-51 or the P-38 in any big way, one over the other...

#1 The P-51 already had the Allison engine in it, the P-51A, or Mustang MkI, it went to the ETO in 1943 and was found unsuitable to high alt combat with the LW, because of the Allison engine specifically. Both the RAF and USAAF rejected it in the Allison engine form as a fighter. It went on to perform well as a Recce fighter in the ETO and it did well in Burma vs the IJAAF.

#2 The reasons for the P-51 going with the Merlin are well documented in countless books, and that reason was the performance at all altitudes given by the Packard Merlin, especially in the cold high alt of the ETO. The Merlin had 600 more hp, and it had better range at certain settings, giving the Mustang its very long range.

#3 The P-38 pilots did not "moan and cry" about converting to P-51s. A few did, some of them aces, most liked the P-51 better in fact. A lot of it came down to perosnal prefs and some had strong loyalties to the P-47 and P-38.

#4 The 4th FG in particular liked their P-47s "the Blakeslsee quote", Blakeslee was not a P-38 pilot, he flew Thunderbolts, I have never seen anything that would indicate Blakeslee would have taken P-38s over P-51s in the ETO, thats for sure.  

#5 The P-51s did just fine in 1945 vs the IJN and IJAAF fighters, Lt. Shomo got the CMH for downing 5 in one sortie in a P-51. There was no big crisis, and the author is just manufacturing history there. In April 45 alone P-51s based from Iwo Jima claimed 50 for losing 17. There was one very bad mission in which 27 out of 148 P-51s were lost due to a very bad weather system they flew into while en route to Japan, I guess this is his big "proof" of something...

#6 P-51s did not have any tendency to shed there tail sections? and the P-51 that was lost in the "story", was probably hit by enemy fire. The RAF and RCAF flew Mustang IIIs (P-51B) untill wars end, and reported no issue that I have ever seen regarding a problem with its tail section. The P-51A units in Burma and the Recce pilots in the RAF also reported no such problem.  The "fillet" added to the P-51D-20 was for added directional stability, as the D had the cut down rear fuselage, thats also well documented, in countless books.

#7 The rest of it is trying to blow up minor problems, like the coolant leaks 1st encountered in the ETO, that all combat a/c  have, into big issues, and all the pro P-38 songs doesnt make it any better of a fighter.

#8 I wonder if he asked the P-51 pilot he spoke to in Idaho if he would have preffered flying a P-40K at 30,000 feet over Bremen, against Fw190s.

If he likes the P-38 thats fine, it had a very good record in the Pacific, and I take no issue with actual documented drawbacks the Mustang may have had, without resorting to revisionism and overblown cherry picking because he likes the P-38 better.

[HoHun]

Hi Agent,

>The P-40F was equipped with a Packard Merlin, mainly because of a shortage of Allisons. It's performance was about the same as Allison-powered P-40s, suggesting that the airframe was the limiting factor in improving the Curtiss fighter's performance.

Hm, that's not entirely accurate. The P-40F was hardly better below the P-40E's full throttle height, but above that the P-40E's performance simply fell off while the P-40F engaged supercharger high gear and kept increasing performance. Above 4 km, the P-40F clearly outperformed the P-40E thanks to its two-speed supercharged Merlin engine.

Not that the Allison was a bad engine - the point the article makes about turbo superchargers is quite interesting, though I don't know the dimensions and performance of the design incorporated in the XP-39.

Fitting the Allison with Merlin-style supercharger technology certainly would have made the engine more competitive, and I believe later in the war, Allison actually did just that and built some very advanced engines. I don't know why they were lagging a bit in mid-war.

Regards,

Henning (HoHun)

[agent 009]

Later Allison engines had 2200 hp, & after war even higher. Tougher than Merlin.

Squire, I didn't write above article. I figured a few Stang fans would not like it, but so it is. Weather losses prove nothing.

The Stang pilot I met in Idaho may have rather had a P-63 or P-38 L. I don't know. I'll ask him if I see him again. I would guess a P-38 as he mentioned meeting only one Japanese plane, which shot up into a climb & left him in the dust.

& remember, the P-63 D with Allison outperformed Mustang D at medium & low altitudes & had topspeed of 437, same as Mustang.

[Squire]

Ya, copy that Agent, I know you got it from somewhere else, just seemed to full of errors to let it go without comment.