Question: P-51B/C gun questions

[SgtPappy]

Question 1)
Was there a standard P-51B/C production block that fixed the gun jamming problem of the P-51B/C and Mustang III? Also, what did the RAF and USAAF do differently to solve the problem?

As many of us know these Mustangs had gun jamming issues. I've read one example of a field-mod where a member of the 354th FG took B-26 ammo feed motors and put them in a P-51B to stop the jamming problem (from P-51 Mustang Vs Fw 190: Europe 1943-45 By Martin Bowman).

The same book states that there were eventual field kits and final factory-stock modifications were implemented for the P-51B/C that solved the problem. It's all over the internet as well, but I can't find any more sources concerning this jamming fix.

Question 2)
Also, in my Great Book of WWII Airplanes, it is stated that some P-51B/C's had 6x .50 cals. Is this correct? I have never seen another source. The same book illustrates some P-51B/C's (by the same artist) with P-51D wings, where the P-51D-type kink in the leading edge is prominent and I don't think that's correct at all.

[Squire]

some P-51B/C's had 6x .50 cals

That's just a misprint/quote. They were delivered with 4 and there was no field mod from any source I have seen where they added 2 more. Even the P-51B/C (Mustang IIIs) flying late into the war had 4 guns wether they were USAAF, RAF or RCAF. Removing a gun from a gunbay is a far cry from adding a gun where no gun bay exists to begin with. 

[Butcher]

Question 2)
Also, in my Great Book of WWII Airplanes, it is stated that some P-51B/C's had 6x .50 cals. Is this correct? I have never seen another source. The same book illustrates some P-51B/C's (by the same artist) with P-51D wings, where the P-51D-type kink in the leading edge is prominent and I don't think that's correct at all.

This is where history becomes a pest and a problem - I've read a few times P51C's carried 6x 50s, not sure which company in the 50s and 60s read wikipedia, however this information was incorrect.
I've made posts in the wishlist in the past about "prototypes" and other things that were incorrect and was called on it, now If I can't figure out something I ask someone like AKAK what his opinion would be, or someone who would know the information.

Basically there is a lot of guessing involved, for example the Russian airforce - its nearly impossible to get decent material on Russian birds during WW2, or Japan for that matter.
Why? Japan was bombed into the stone age, factories that produced the aircraft were bombed, so where else would the golden egg be?

Most common mistakes are usually "prototypes" for example in one thread someone declared the Ki-84 flew with 4x 20mm cannons, however from what I gather it had 3 prototypes, one crashed - so a third had to be made, it wasn't put into production.
Gun packages are another, for example German Field Modification Kits - some housed up to 6x 20mms per wing - looks great on paper, but the idea wore off once you realize at this time there were hundreds of escorts - and a fighter that couldn't turn - and had to fly a straight line into bombers - was a sitting duck.

[SgtPappy]

Field mods are a very interesting thing that would be nice to be in Aces High in the future sometime.

I think they really bring out the potential in a lot of planes. But yes, it's hard finding info on a lot of planes, which is why I ended up here... after reading all this questionable information that I mentioned earlier.

[Karnak]

Most common mistakes are usually "prototypes" for example in one thread someone declared the Ki-84 flew with 4x 20mm cannons, however from what I gather it had 3 prototypes, one crashed - so a third had to be made, it wasn't put into production.

You're mistaking the two 20mm and two 30mm for the four 20mm armaments.  Several hundred Ki-84's were produced with the four 20mm guns while only two or three prototypes were built of the two 20mm and two 30mm armament.  I've even heard that due to lack of availability on the gun it was two 20mm and one 30mm.

[mthrockmor]

I may be misunderstanding this discussion and a few other comments in other threads. Is there a P-51B model that went into combat with 4x20mms? I 'think' it was something like the A-36, ground attack and basically a B model with bomb racks and 20mms?

If so, would this not make for a perked upgrade? I say perked because I know I and other PonyD drivers would wreck havoc with that gun package.

Boo

[Karnak]

I may be misunderstanding this discussion and a few other comments in other threads. Is there a P-51B model that went into combat with 4x20mms? I 'think' it was something like the A-36, ground attack and basically a B model with bomb racks and 20mms?

No, that was the Allison engined Mustang Mk Ia.

[Butcher]

You're mistaking the two 20mm and two 30mm for the four 20mm armaments.  Several hundred Ki-84's were produced with the four 20mm guns while only two or three prototypes were built of the two 20mm and two 30mm armament.  I've even heard that due to lack of availability on the gun it was two 20mm and one 30mm.

Interesting, I have a couple of manuals and books, I didn't see anything on the 30mm version - then again I don't even have the production numbers or prototypes, one books in Japanese and the other Polish.

[SgtPappy]

I just read in Mustang Aces of the 9th & 15th Airforces & RAF by Jerry Scutts that the RAF saw less gun jamming issues due to their low alt operations which saw less gun freezing. I wonder then how the USAAF fixed their B's and C's or if there was a factory-kit that fixed new P-51s.

[Guppy35]

I just read in Mustang Aces of the 9th & 15th Airforces & RAF by Jerry Scutts that the RAF saw less gun jamming issues due to their low alt operations which saw less gun freezing. I wonder then how the USAAF fixed their B's and C's or if there was a factory-kit that fixed new P-51s.

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.

[drgondog]

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.

The primary issues for the slanted guns were a.) ammo feed motor freezing up and as you noted, G forces affecting ammo feed (more on one side than other due to the slant.

The only difference in the P51D/K wing from the B/C was the greater root chord to enable the extended angle 'strake'.

Same arfoil and dimensions from 61.5 all the way out to the tip where the guns and ammo were placed.

 From Wing Station 61.5 they were the same except for adding the extra .5 space in gun and ammo bays, exhaust chutes, etc.  As far as the armament, the 50's were indeed placed vertically, the inboard ammo capacity increased, improved electric gun heaters were installed. Field modifications included making changes to the buffer springs inside the M2 plus various other changes to reduce stoppages.

 

[Guppy35]

Any idea why the slanted 50s?  I apparently bought the wrong explanation.

[SgtPappy]

Wow, ok because most of us were under the impression that the wings were thinner. Thanks for enlightening us, Drgondog. I'd really like to see a schematic of the P-51B/C and D wing stations if you have them.

But like Guppy said, why were the guns slanted if they ought to have fit in vertically? Did any of the field-mods come in kits from North American like some sources say?

[drgondog]

I have no idea why they were slanted - remember the wing/bays for the P-51, and the Mustang IA, were constructed so that 4x20mm guns plus 125 rounds each were belt fed into them.

[MK-84]

Responding to the idea of "should we have field mods"  I dont want to fight an enemy knowing that it "might" have something rare and totally different from what I would expect.  If I fight a P51, I expect it to perform like a P51, just like any other aircraft.  The exception is the F4U's where you could potentially  expect anything (which might have something to due with perk cost) 
    What I mean is, I know what a 190 is generally capable of, and I know what a zero is generally capable of.  Adding too many vaients makes it too difficult to be able to make the decision of how to fight it.
    In AH gameplay that removes alot of the fun of the fight.  Knowing what your enemy can and can not do makes for a better experience.
    Fighting a F4U is inmho one of the largest upsets to this until you get in icon range, and thats fun!  But add too many and it becomes a crapshoot on what tactics to use.