PDA

View Full Version : P51 B/C vs P51D



nsteense
10-06-2008, 02:07 AM
Can someone tell me or know a reference which can explain me the differences between the P51 B/C and D models? Apart for the obvious tear drop canopy, of course. http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif
Was it a carry over design with tweaks and improvements or was it a complete redesign?
I'm currently reading the war exploits of Lt Goebel in the MTO, and at some point he's describing the change over from the B to D model. One of the things he mentioned was that the wing was redesigned, in order to prevent gun jamming under high G load, so I became curious.

Erkki_M
10-06-2008, 02:35 AM
In game:

C = B with different canopy (slightly better visibility) and a few kmph faster. D = C but some 20kmph faster, completely different cockpit with way better visibility. At low altitudes D climbs worse than C or B (at higher alts its roughly equal), it has 2 machine guns more but its doesnt turn nearly as well. B and C also retain energy slightly better.

I prefer D: speed and visibility.

horseback
10-06-2008, 10:13 AM
In real life as opposed to the game, the transition from the razorback Mustang to the bubbletop involved a few tradeoffs.

The bubbletop models offered a few fixes to the perceived faults of the B/C, some of which were already 'fixed' by the time the bubbletop D/Ks arrived in the ETO.

1. The base model B/C had terrible side and rear field of view for the pilot, due to the framing and lack of headroom. The RAF ordered bulged sliding Malcolm hoods for their Mustang IIIs, and many Mustang pilots preferred the Malcolm hoods when they could get them over the bubbletop Mustang. They were, however, not easy to get, even in the ETO, 'next door' to the RAF.

The bubbletop was not bulged outwards and the pilot had less FOV to the rear and below. Neither aircraft had a particularly good forward view.

2. The B/C came with four .50 M2 HMGs, whose fault was not a lack of 'punch' so much as a distressing tendency to jam the moment the aircraft rolled and flexed the wings a bit. This was due to the guns' muzzles being flush with the wing leading edge for lower drag, and the resulting need to lay the guns at an angle within the wing, creating an awkward angle for the ammo feed. By late spring of 1944, the 8th AF had adapted ammo feed motors from one used on medium bombers.

The bubbletop fix pushed the guns forward a bit, allowing them to be set upright within the wing, and added an extra gun per wing. The extra weight and I believe some mods to the landing gear led to the 'cranked' angle of the leading edge to be increased somewhat on the D model, so that the wing was wider at the root than in the razorback ponies. The wingroot itself was not thicker in profile, from what I've read.

3. The engines on the B/C were optimized for higher altitude performance; coupled with the slightly lower weight of the razorbacks, this resulted in a higher top end at altitude. The bubbletops however, had better performance at medium altitudes, which came in handy when you chased your intended victim down in a dive.

4. Cutting down the rear fuselage was not as major a modification from a production/design standpoint as one might think. The problem was that with the loss of side area, you lost a bit of stability in the horizontal plane; the D/K models tended to fishtail and skid a bit more than the razorbacks.

However, the basic airframe was designed for the less powerful Allison engine, and even the B/C models were less refined in their handling than the Allison powered models (this still made them lightyears easier to handle than any P-40). The addition of the fin fillet to the D/K models in late summer 1944 made them about as stable as the B/Cs, but a number of B/Cs also got the fin fillet mod too, which leads me to suspect that these were even more refined in their behavior at high speeds.

cheers

horseback

ElAurens
10-06-2008, 10:53 AM
The B/C models were about 20mph faster than the D.

JtD
10-06-2008, 11:27 AM
In game B/C both have the -3 Packard, the D has the -7. The -7 delivers more power at lower altitude and less up high.
I think that IRL there were a few B/C with -7 as well as a few D with -3.
The plane as such was changed only a little, see posts above.

jarink
10-06-2008, 11:32 AM
Two very good and well researched sources for info about the different versions of P-51:

MustangsMustangs P-51 Variants (http://www.mustangsmustangs.com/p-51/p51variants/Home.shtml)

Joe Baugher - P-51B/C (http://home.att.net/%7Ejbaugher1/p51_8.html)
Joe Baugher - P-51D/K (http://home.att.net/%7Ejbaugher1/p51_10.html)
The whole P-51 lineup (http://home.att.net/%7Ejbaugher1/p51.html), from Na-73 to the Piper Enforcer.

Kocur_
10-06-2008, 01:23 PM
Originally posted by horseback:
3. The engines on the B/C were optimized for higher altitude performance; coupled with the slightly lower weight of the razorbacks, this resulted in a higher top end at altitude. The bubbletops however, had better performance at medium altitudes, which came in handy when you chased your intended victim down in a dive.

This is selfexplanatory if it would be V-1650-7 in D vs. V-1650-3 in B/C. But lots of the latter had V-1650-7.
Were V-1650-7 in D different to V-1650-7 in B/C?

nsteense
10-07-2008, 12:36 AM
Originally posted by jarink:
Two very good and well researched sources for info about the different versions of P-51:

MustangsMustangs P-51 Variants (http://www.mustangsmustangs.com/p-51/p51variants/Home.shtml)

Joe Baugher - P-51B/C (http://home.att.net/%7Ejbaugher1/p51_8.html)
Joe Baugher - P-51D/K (http://home.att.net/%7Ejbaugher1/p51_10.html)
The whole P-51 lineup (http://home.att.net/%7Ejbaugher1/p51.html), from Na-73 to the Piper Enforcer.
Thanks for the links and the posts!! It looks like they can supply me the answers I'm after.
By the way, I was talking of real life differences, not in game differences, which are a bit biased anyway.