Question: P-51B/C gun questions

[SgtPappy]

Hmm I agree somewhat... but the thing is a lot of the best field mods were in place near the end of the war. The field mod we have here is really just one that allows for guns to work. In AH, however, guns don't jam so that's a big plus.

But like I said earlier, it seems that a lot of the performance-modified planes were late war aircraft. For example, by 1945, so many P-51s/47s/38s, Spitfires and Tempests were using 150 grade fuel to boost their performance. Also, your comment of "adding too many variants" sort of applies to Spitfires and 109s in that there are so many different variants, you don't know how to fight it exactly till within icon range. A lot of the time, people just prepare for the worst case scenario and then figure out what they can and cannot when they get a closer look. I like field mods in that they seem to bring out an plane's full potential and during WWII, fighting any ol' 109 didn't always mean it was just another 109.

With respect to the P-51 guns, I've seen some pictures of the gun bays and it actually looks as if the guns are slanted as to avoid staggering the guns and putting a gun barrel into the free-stream air. That is, the slanted gun allows one ammo belt to be fed almost on top of the other ammo belt. The P-51D seems to spread the guns slightly so that one of the belts can feed around the other guns and into its own gun. See the P-51B and D gun bays below:

Mustang P51B/C/III


Mustang P-51D/IV


Finally, I found a site that has more detail concerning the field-modified guns but it doesn't offer up any sources. The excerpt is:
The B model, with two canted .50s in each wing, had a fault not discovered until used in combat. The feed mechanism, designed to lift 35 pounds of ammunition, was not enough to pull the belted ammunition through the articulated ammo tracks during violent maneuvers, resulting in many stoppages. The inboard guns' ammunition trays each held 350 rounds and the outboard guns each carried belts of only 280 rounds. The fact that the four guns were mounted in a slanted position also contributed to stoppages. Booster motors with star wheels salvaged from Martin B-26 turrets did the trick of providing the extra energy to properly feed the guns. The boosters were so successful that additional quantities were requisitioned to modify all B models. from http://www.cebudanderson.com/viewfromtheline.htm

[Charge]

Also notice that the feed direction is different in B and D configurations. Is it possible that the feed direction was not switchable in early Brownings so the starboard guns in B had to be slanted to allow proper feed, but not the port side guns?

-C+

[SgtPappy]

Well, no because the guns are slanted in both wings, not just one. Another explanation I found is given in 359th Fighter Group by Jack Smith. Here is an excerpt relating to the gun jams:

Field work eased the problem, but 368th FS armourer Larry Lovell exposed a major fault with the individual weapons... He stated that the machine guns manufactured by Kelsey Hayes, under contract from Browning, were of inferior quality... they would jam after just a few rounds... crates of Kelsey Hayes replacement guns were not accepted by the 368th.

However, careful attention to the loading of ammunition by armourers paid big dividends, as was demonstrated in the group's June 1944 records which revealed that just one gun stoppage was reported among the 368th's P-51B/Cs and 3410 rounds were expended.

[MAINER]

I wish aces high would acknowledge the existence of field modifications and somehow integrate them into the game.

[SgtPappy]

Perhaps one day but it's a big undertaking and I think the general consensus on the BB is that people would rather not have them.

[smoe]

Weren't the C's the same thing as a D except for the obvious birdcage canopy a maybe a few other details?

[drgondog]

Weren't the C's the same thing as a D except for the obvious birdcage canopy a maybe a few other details?

No - the P-51C was the same as the B except it was made in Dallas and delivered several months later into the ETO.

Having said that, the B/C were very close to the D as far as the BOM is concerned with the major changes of removing turtle deck, installing new more sloped windshield and bubble canopy, changing the wing root and associated inboard wing from station 61.5 to C/L, adding mounts and modifying gun bays to include an extra .50 in each wing, changing the wheel door cover as well as uplock mechanism and one or two more changes,,

[Guppy35]

No - the P-51C was the same as the B except it was made in Dallas and delivered several months later into the ETO.

Having said that, the B/C were very close to the D as far as the BOM is concerned with the major changes of removing turtle deck, installing new more sloped windshield and bubble canopy, changing the wing root and associated inboard wing from station 61.5 to C/L, adding mounts and modifying gun bays to include an extra .50 in each wing, changing the wheel door cover as well as uplock mechanism and one or two more changes,,

So when is the redone "Angels, Bulldogs and Dragons - History of the 355FG in WWII" coming out?   

[drgondog]

So when is the redone "Angels, Bulldogs and Dragons - History of the 355FG in WWII" coming out?   

Guppy - thanks for your interest.  I am delivering the 'package' to Schiffer in June.. approximately 500 pages plus another 500-800 photos and 60 high def color side elevations by Steve Deisely of the Group's (plus Scout Force) fighters flown out of Steeple Morden..

80% WWII but inclusion of 355TFW victory credits and losses from Vietnam plus some superb narratives from Billy Sparks and John Piowaty from Weasel and Strike Force POV in F-105F and D.  The 355th TFW in Vietnam and the 355FW (A-10) in Middle East/Afghanistan will be detailed in Our Might Always - Volume II.

Same Diary format but brings in the rest of the 8th AF notable days as well as deep dives into major air battles crystallizing the LW order of battle as well as US.

Last I will include the tabulation of all the 8th AF Fighter Groups (as well as the 354th because they were so important) breakdown of air and ground victories by a/c flown and scores by type shot down - as well as the breakdown of ETO victory credits (per USAF 85) by fighter type by period that I have shared here.

[Guppy35]

Consider one sold already. Very much looking forward to it 

[Hajo]

Save one for me 

[drgondog]

Thanks to both of you.  The book will have a chapter on 8th AF FC operations along with the data I have shared here on ETO victory credit totals as a supplement to discuss the multiple phases of 8th AF Operations.

[Soulyss]

Another book for the 'ol wishlist. 

Looking forward to it.   

[Shuffler]

I think in the end it was the transition to the 51D that fixed the issue.  The guns in the B/C were installed slanted in the thinner wing of the B/C.  This too contributed to the problem at higher Gs.  The solution really was he installation of the guns upright as was done in the D model with had the wing redesigned to allow for this.

Up til then it was the field mods and resourceful crew chiefs that did their best to keep the guns going on the early Merlin 51s.

^^ This is what I read also.

[Shuffler]

No - the P-51C was the same as the B except it was made in Dallas and delivered several months later into the ETO.

Having said that, the B/C were very close to the D as far as the BOM is concerned with the major changes of removing turtle deck, installing new more sloped windshield and bubble canopy, changing the wing root and associated inboard wing from station 61.5 to C/L, adding mounts and modifying gun bays to include an extra .50 in each wing, changing the wheel door cover as well as uplock mechanism and one or two more changes,,

Also added a strake in front of the stab for longitudinal stability after cutting down the area behind the canopy.