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

[DAVIDICUS]

Just wondering.

Other American fighters with wing mounted fifties had the business end of their barrels flush with the leading edge of their wings.

 

[wmaxt]

Just wondering.

Other American fighters with wing mounted fifties had the business end of their barrels flush with the leading edge of their wings.

They were set up for clearance in the wing. Two considerations are critical thickness/shape of the chord (side view of the wing cut through at the point of interest) to allow the breach to operate without interference. In the P-47 it's further foward and had 1 more gun to accomodate.
Second the breaches are staggered to allow the ammo belts to follow a straight line.

The Laminar flow airfoil used on the P-51 the thick part of the wing is further back allowing the barrels to remain hidden while still allowing for staggered breaches on the guns.
The P-40s had thicker wings (older less efficent airfoils) allowing more flexibility in locating the guns.

 

[DAVIDICUS]

I think all planes with wing mounted fifties had to deal with the issue of ammunition belt placement and the P-47 had thicker wings in the critical area than other aircraft with flush leading edge mountings.

Am I wrong here?

 

[wmaxt]

I think all planes with wing mounted fifties had to deal with the issue of ammunition belt placement and the P-47 had thicker wings in the critical area than other aircraft with flush leading edge mountings.

Am I wrong here?

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!

 

[Anonymous]

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

 

[Vahe Demirjian]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

 

[fubar57]

Wing spar and ammo tracking as well

 

[FLYBOYJ]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

Your source for that statement????

 

[Vahe Demirjian]

Wing spar and ammo tracking as well

View attachment 566821​

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

 

[fubar57]

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

?
?
?​

 

[Graeme]

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

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)

 

[rednev]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

So they put all that effort into turbo charging to create a high altitude fighter=bomber ?

 

[Sid327]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

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

Are you serious....or just trolling?

 

[Wurger]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

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

WOW! ... THX for sharing.

 

[pinehilljoe]

Fubar's cutaway showing the wing spar says it all. The guns were accommodated into the wing, not the wing to the guns.

 

[Milosh]

 

[pbehn]

The P-47 wanted long barrels like the Spitfire, which were better because they were closer to the enemy. Its obvious really like a darts player getting closer to the dart board by leaning. Hope this helps.

 

[DerAdlerIstGelandet]

The P-47's gun barrels protruded very far because the P-47 was intended as a fighter-bomber.

Ummm no, take a look at the photos of the spar, ammo feed and tracks. It has nothing to do with the type of aircraft role they played. And besides, that the barrels are all the same length. They are just built into the wing at different locations.

 

[pbehn]

To get the guns almost flush you need complicated feed arrangements. This off the net is the P-51D.

the pic source: https://live.staticflickr.com/3804/18419701703_b14ff4ac19_c.jpg

 

[DerAdlerIstGelandet]

The P-47 wanted long barrels like the Spitfire, which were better because they were closer to the enemy. Its obvious really like a darts player getting closer to the dart board by leaning. Hope this helps.

I stand corrected from my previous post.