Why did the P-47's gun barrels protrude so far?

No, they were light bombers. Heavy bombers dropped boulders .................

DerAdlerIstGelandet said:

I will contact him.

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Please do Chris. Appears we're not the only ones...

I wrote him. We talked. We'll see...

Vahe Demirjian said:

The P-40 and P-51 had extremely short gun barrels because they were air superiority fighters.

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I'll be damned...

This whole time I thought it was because the engineer in charge of designing the P-47's looks was also an Organist at the local Church and thought if a pilot saw the "pipe organ" effect on his wings, he would be inspired in battle.

His first design was a plastic Jesus on the dash, but it blocked the gunsight...

Graeme said:

Nice photo of the belt feed for each machine gun...

View attachment 566824

However based on that photo - I would've felt the staggered gun lengths would be reversed like this, to assist the belt feed?
(But I am drinking rather heavily tonight)

View attachment 566825

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Your arrangement has the ammo feed going over the receiver (the ammo feed is into the extreme forward end of the receiver). The way the factory did it the ammo only has to clear the barrels.

The first P-47's had 267 rpg. The later ones had 425 rpg. The P-47N had 500 rpg. The mounting of the guns as showed by fubar57 allowed the P-47 to carry more ammo than any other fighter.

Now, on a more serious note, the earlier F4F's had gun barrels protruding from the wing while the later ones did not. Ancient Aliens theorists think that extraterrestrials were involved in this design change. Me, I'm not so sure.

MIflyer said:

The first P-47's had 267 rpg. The later ones had 425 rpg. The P-47N had 500 rpg. The mounting of the guns as showed by fubar57 allowed the P-47 to carry more ammo than any other fighter....

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That's some serious firepower (3,400-4,000 total rounds). It must be noted though that with full internal fuel the P-47 normally carried two less machine guns and 300 rpg for a total of 1800 rounds:

III Condition of Aircraft Relative to Tests

A. Flight tests were conducted at a take-off gross weight of 13,230 lbs. with the c.g. at 29.9 MAC, wheels up. This weight corresponds to the full combat weight of the airplane and includes full internal fuel, 15 gallons of water and ballast for 300 rounds of ammunition per gun.

P 47D Performance Test Using 44-1 Fuel



http://www.wwiiaircraftperformance.org/p-47/P-47D_43-75035_Eng-47-1714-A.pdf

By comparison the F6F and F4U had a total of 2,400 and 2,350 of .50 cal rounds respectively, while the P-51D carried between 1,880-2,080 rounds (later D models carried the lesser amount). All of these figures are with full internal fuel for a typical combat mission.


Could the P-47N really carry that much fuel?

Yes, the P-47N had longer wing with added fuel, extended at the root and clipped at the tip, to enable it to be used for VLR escort of the B-29's. They only got one such mission in before the war ended.

GrauGeist said:

His first design was a plastic Jesus on the dash, but it blocked the gunsight...

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"I don't care if it rains or freezes..."
"What we have here...is a failure to communicate."

Anonymous said:

Well, the max chord at the center is not the only reason. This is true, but the P-47 wing is thicker and also wider (front-to-back). Because the wing of the P-51 is quite a bit smaller than that of the P-47, there was no reasonable option to fully stagger the guns. As can be seen in the image below, the two outer guns are not staggered at all, and the ammo trays lie one atop the other, which is why they are limited to only 280 rpg as compared to 400 for the inner gun. The inner gun is staggered back about 1/2 the length of a round, and the ammo belt has to twist slightly back to reach the second ammo tray. This arraingment also required the guns to be set further apart than those of the P-47.

Images from Flightjournal.com - P-51 in Detail.

Perhaps someone can find a good photo (I've looked but no luck right now), but on the P-47 it was possible to stagger each gun enough that the belt could feed strait into the gun from its own ammo tray w/o any twisting of the belts. To accomplish this, 3 of the gun barrels must protrude significantly from the wing. Each gun could have up to 425 rounds of ammo (though usually less was carried).

=S=

Lunatic

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is what 50 caliber gun was in the P-47 Thunderbolt - Google Search

wmaxt said:

Pretty close, the wing profile defined where the Breaches to the guns went. The P-47s wing was thicker further foward than a Lamininar Flow wing like the P-51.

The P-47 also had 4 guns each side instead of 3 which affected placement somewhat.

The early P-51s (Bs and Cs) had a lot of trouble because of the tight quarters in the thin wing. They finaly used feed motors from B-26s to keep the guns from jamming!

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Resp:
Yes, a P-51 Enlisted maintenance crew member, who was familiar with the B-26 . . . put two and two together after studying the problem . . drove to a nearby bomber base to acquire the necessary equipment to fix the jamming of the B/C variant wing mounted guns, which occurred when firing during a tight turn.

The B/C and D wings are fundamentally the same, one isn't "thinner" than the other. The guns in the B/C wings were canted ~60° (from wing) to outboard* requiring the ammo belts to go over the top of the receiver and doubling back into it. On the face of it this seems rather awkward and results in many face-palms among the Internatti but it appears, to me anyway, that this was to allow, once the guns were properly adjusted, a very quick and easy way to change the aiming point range; when you adjust the guns along the gun's vertical it swings the bore-line laterally as well as vertically. Do this equally with all four guns and make a quick adjustment on the gunsight and you're done. You can go from 200 yards to 500 yards with a single adjustment per gun and be properly sighted in without firing a single test shot. The feed part of this, though, wasn't up to the task and it failed and even the belt drive motors added later, while they helped, didn't completely solve this problem. In the D this clever but unreliable feature was abandoned and the guns were put in the conventional upright position with some of the belts doing slight vertical zig-zag action but it worked reliably with the result being that you needed to adjust the guns both vertically and horizontally every time you re-ranged them.

*B/C right gun bay vs. D left gun bay halfway down in this thread:
Warbird Information Exchange • View topic - P-51D Wing Thickness Versus P-51B/C