What's the purpose of the P-47's protruding barrel sleeves?

[trackend]

http://www.cornwall-online.co.uk/history/pasty.htm
mind you this still dont give the reason for the name

 

[Matt308]

So to quote page one of this rather diverse thread...

"The primary wing spar on the P-47 is located right behing the gun bay and 4 guns must be staggered to accomodate the perpendicular feeding belts from the magazines. This is the primary reason for the staggered design of the .50 BMGs and thus perhaps one (1) rationale for the exposed blast tubes. However, to come full circle, I will bet you bottom dollar that ease of maintenance ranks right at the top."

I knew you guys would come around.

 

[Monkeysee1]

Matt 308, you said that the P47 was designed for ground strafing? WHAT?!? No man, it was designed as a high altitude fighter first and foremost. Its superiority as a ground attack aircraft was incidental.

All US aircraft have blast tubes mounted for their .50's. The P47's are staggered to allow more ammunition to be carried and allow separate feeding of the guns so they don't interfere with each other. Other US aircraft don't have this staggered design necessarily because this was a side benefit of the elliptical wing the P47 used... and let's face it... it was a big enough wing to allow this.

Pretty sure on this one but if I'm wrong, let me know.

 

[the lancaster kicks ass]

i can't believe you don't know what a pasty is les!

 

[cheddar cheese]

I had an Italian pasty in Spain. Its like a pasty but with ham, cheese, and tomato. And its a piza base instead of pastry, but still.

 

[lesofprimus]

Pasty is what u call the little geeky pale kid who looks like he was inside a nuclear reactor for 2 months........

"Damn Tommy, your skin looks so pasty dude..."

However.........

"Man, Ill tell you, that pastry that Lanc gave me was awesome... Had cheese and ham and little Rosemary in it...."

 

[cheddar cheese]

Well the Cornish are odd.

 

[chuter]

Wow, stumbled across this old thread and saw no real answer for the OP (I hope he hasn't already passed on ...lol). Technically, what the P-47 has on its barrels aren't blast tubes. Blast tubes are located ahead of a gun muzzle, when the muzzle is still inside the aircraft, to protect the structure (the Mustang uses a short one on the inboard, staggered gun). What the P-47 uses are actually a non-perforated cooling jacket or sleeve. The reason is because the barrels protrude from the leading edge of the wing which usually causes serious problems with the airflow, particularly at high angles of attack, because the standard or ventilated jackets cause a lot more turbulence. This becomes a much bigger issue with laminar airflow wings. The ideal goal is to have the guns housed entirely within the wing or, if not possible, have the protruding barrel act as little like a vortex generator as possible by making it more aerodynamic with a non-perforated jacket or a fairing. Take the laminar winged Hawker Tempest as an example: early production had protruding, faired barrels while the later production had the flush Mk V short barrel cannon. There were multiple reasons for going to the Mk V but the Mk V itself was developed as an aircraft cannon with a short barrel for aerodynamic as well as other reasons.

And now, maybe, the topic can fade back into obscurity with dignity ... lol.

 

[Njaco]

D@mn ! Where did all this dust come from?

Thanks chuter! Great info.

 

[syscom3]

Wow. Heck of a post from a new member. Well done!

 

[glennasher]

I thought maybe it was to stagger the MG receiver placement in the wings, to make more room for the ammo belts to travel from magazine to MG. M2 receivers are quite long, and staggering them in relationship to each other would seem to allow more room for the feeding mechanism. But that's just another guess.

 

[tomo pauk]

+1 on that.

 

[Elmas]

These sleeves seem to be present in the italian Serie 5 fighters.....