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FA_Maddog
09-08-2004, 04:05 PM
With the Pacific Fighters coming out this fall can anyone provide charts with the correct speeds for the P-51A's, B's, &C's with the Allison V-1710-39 (1150 HP) engine, V-1710-81 (1200 HP), & V-1710-87 (1325 HP). This plane was used in the PTO at low to medium altitudes and from what I have read its performance was excellent at this height. Maximum speed was 390 mph/627km/h, but at what altitude? What was the maximum sea level speed? I had thought I had read somewhere it was around 369 mph. at sea level. or was that for the Merlin powered?

[This message was edited by FA_Maddog on Wed September 08 2004 at 03:13 PM.]

FA_Maddog
09-08-2004, 04:05 PM
With the Pacific Fighters coming out this fall can anyone provide charts with the correct speeds for the P-51A's, B's, &C's with the Allison V-1710-39 (1150 HP) engine, V-1710-81 (1200 HP), & V-1710-87 (1325 HP). This plane was used in the PTO at low to medium altitudes and from what I have read its performance was excellent at this height. Maximum speed was 390 mph/627km/h, but at what altitude? What was the maximum sea level speed? I had thought I had read somewhere it was around 369 mph. at sea level. or was that for the Merlin powered?

[This message was edited by FA_Maddog on Wed September 08 2004 at 03:13 PM.]

lrrp22
09-08-2004, 04:13 PM
Maddog,

Only the P-51, P-51A, and A-36 mounted the Allison engine. The P-51B/C was powered by the Merlin.

369 mph at sea level is more in-line with a Merlin V-1650-7 equipped P-51B/C/D than an Allison Mustang. However, I have seen a claim that the RAF ran their Allison Mustang I's and/or II's at 72" manifold air pressure, as oppossed to the more common 54" MAP. If this is true, then those Allison-engined Mustangs would have been very fast at low level.

Also, The P-51A did 390 mph at around 14,000 ft, IIRC.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FA_Maddog:
With the Pacific Fighters coming out this fall can anyone provide charts with the correct speeds for the P-51A's, B's, &C's with the Allison V-1710-39 (1100 HP) engine. This plane was used in the PTO at low to medium altitudes and from what I have read its performance was excellent at this height. Maximum speed was 390 mph/627km/h, but at what altitude? What was the maximum sea level speed? I had thought I had read somewhere it was around 369 mph. at sea level. or was that for the Merlin powered?<HR></BLOCKQUOTE>

FA_Maddog
09-08-2004, 04:25 PM
Thanks for the correction Irrp. One book of mine showed a picture of a P-51C flying over Burma with what they said had the Allison engine in it in 1943. I was wondering about that, couldn't find it in AHT. See how wrong some of this stuff is. This is why I'm asking.

JG53Frankyboy
09-08-2004, 04:35 PM
http://home.att.net/~jbaugher1/p51.html

and to identify an allison mustang from a packard/merlin one.

the Allison Mustangs have alsways their carburotar intake on the upper side of the cowling .

SkyChimp
09-08-2004, 08:19 PM
Mustang I
@ 8625 lbs
44.5" hg manifold pressure and 3,000 rpm
328 mph @ 1,000 ft
382 mph @ 13,700 ft

=====

A-36
@ 8955 lbs
366 mph @ 1,000 ft @ 52" hg and 3,000 rpm
368 mph @ 14,000 ft @ 35" hg and 3,000 rpm

=====

P-51A
@ 8,633 lbs
409 mph @ 10,000 ft @ 52" hg and 3,000 rpm *


* The P-51A (Mustang II) was tested at Boscombe Down in August 1943. Serial number was FR893. The plane was tested at 52" manifold pressure. Best climb rate was 3,800 fpm and 20,000 feet was obtained in 6.9 minutes. Not sure why the plane was apparently test at 52" hg manifold pressure. That was "take-off" power for the V-1710-81 Allison engine. WEP was 57" hg and that could be maintained to just above 10,000 feet. The plane was "overboosted" to 60" hg with a "tremendous" increase in performance, but I don't have figures for that.

75" hg mentioned in a post above was too high for an Allison power Mustang and I doubt any operational Allison P-51 flew with a manifold pressure that high. Manifold pressures that high were not common in Allison powered Mustangs until the P-82, when hg at WEP was 100".

Regards,
SkyChimp
http://members.cox.net/us.fighters/SkyChimp_flying.jpg

k5054
09-09-2004, 02:37 AM
Mustang I with F21R engine 377mph at 4,000ft, Mustang II with F20R 409mph at 10,000, testing figures from Boscombe Down which gave the RAF the idea that there was something special about Mustang's drag and it needed a high-alt engine.
409 at 10,000 is equivalent to 369 at s/l, using the rule of thumb of 4mph per 1,000ft. (That rule always works, 1% of max lost per 1,000 below rated alt.)

FA_Maddog
09-09-2004, 07:40 AM
Thanks guys for the information. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

actionhank1786
09-09-2004, 09:00 AM
You know Maddog. I was actually in the local hobby town the other day, and found a book i think from Osprey Books titled "Allison Engined Mustangs" if you're interested you should give it a look.

http://img18.photobucket.com/albums/v54/Halfwayhank/Actionsig.png

Actionhank
~Aaron White

FA_Maddog
09-09-2004, 04:15 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by actionhank1786:
You know Maddog. I was actually in the local hobby town the other day, and found a book i think from Osprey Books titled "Allison Engined Mustangs" if you're interested you should give it a look.

http://img18.photobucket.com/albums/v54/Halfwayhank/Actionsig.png

Actionhank
~Aaron White<HR></BLOCKQUOTE>


Thanks, I'll look for it.

No3 Spit
09-09-2004, 07:35 PM
Interesting discussion, but in game I wonder why the C model is such a poor handling aircraft compared to the other marks modelled..an FM debate to be sure!.. but I hope that it is just an oversight as are the weak .50cals with just a tune up required in any future patches

steiner562
09-09-2004, 08:16 PM
Weak 50 cals?!&gt;!? ROFL!,in ealrier vers of the game I would have agreed with you but in 2.04 I cant see how anyone can complain about them, they are offically x-wing lasers nows not 50cals.

http://www.bf109.com/gallery/grayeagle/gallgray01sm.jpg
"The 109? That was a dream, the non plus ultra. Just like the F-14 of today. Of course, everyone wanted to fly it as soon as possible. I was very proud when I converted to it."
Major Gunther Rall, German fighter ace, NATO general, Commander of the German Air Force. 275 victories.

[This message was edited by steiner562 on Thu September 09 2004 at 07:36 PM.]

BlackStar2000
09-10-2004, 11:16 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by No3 Spit:
Interesting discussion, but in game I wonder why the C model is such a poor handling aircraft compared to the other marks modelled..an FM debate to be sure!.. but I hope that it is just an oversight as are the weak .50cals with just a tune up required in any future patches<HR></BLOCKQUOTE>


sry but!

LEARN TO AIM

lrrp22
09-10-2004, 12:07 PM
Actually, it was 72" that is mentioned in Osprey's P-51 "Production line to Frontline" book.

I suspect that the author mistakenly used the 72" Hg figure to indicate the increased boost used by the RAF (probably 60"?).

As far as the RAF's testing of the Mustang II, I had wondered where the 409 mph@10K and the 3800 fpm climb numbers originated. AHT quotes the much more conservative NAA/USAAF data. Why is that the the RAF usually seems to be the best source for detailed performance testing of US aircraft?

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by SkyChimp:

75" hg mentioned in a post above was too high for an Allison power Mustang and I doubt any operational Allison P-51 flew with a manifold pressure that high. Manifold pressures that high were not common in Allison powered Mustangs until the P-82, when hg at WEP was 100".

_Regards,
SkyChimp_
http://members.cox.net/us.fighters/SkyChimp_flying.jpg <HR></BLOCKQUOTE>

k5054
09-10-2004, 03:31 PM
I have Jeff Ethell's Mustang, a documentary history.
In a report by a US officer about RAF Mustang Is, dated aug 43,he states the British removed the auto boost control, and for emergency had operated at full throttle at s/l for 20min at a time, at 72in hg.
I suspect that's how Boscombe got the high speed and climb figures, using boost which was unthinkable for Wright Field, or even Allison themselves.

lrrp22
09-10-2004, 04:02 PM
Interesting, that's pretty much exactly the same claim made in the Osprey book. It's likely sourced from the Ethell book.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by k5054:
I have Jeff Ethell's Mustang, a documentary history.
In a report by a US officer about RAF Mustang Is, dated aug 43,he states the British removed the auto boost control, and for emergency had operated at full throttle at s/l for 20min at a time, at 72in hg.
I suspect that's how Boscombe got the high speed and climb figures, using boost which was unthinkable for Wright Field, or even Allison themselves.<HR></BLOCKQUOTE>