Which fighters were "thick skinned?" (2024)

A colleague at work told me that the P-51 had a thick aluminum skin and that
this thick skin allowed the engineers to use less structural reinforcing members in the frame. He said that the P-51's skin, for instance, was thicker than the P-47's and that as a result, the P-47 required more structural bracing.

On a somewhat related note, I understand that the P-51, aka, the "Spam Can" was rather flimsy and read that one pilot that flew both the P-47 and P-51 said that the P-47 was built like a machined tool while the P-51 had a cheaper, stamped construction.

The P-51, like almost all American fighters, had comparatively thick duraluminum sheeting. However, it also had comparatively more structure than its foriegn counterparts.

Your comparison is incorrect. The P-47 had thick sheeting even for an American plane - it was commonly refered to as "double thick". Flight crews could walk freely upon the P-47 wing anywhere but out at the very tip of the wing (and I mean the last inch or so) or on the control surfaces with their boots w/o concern about denting it. By contrast, the Spitfire, the FW190, and the Bf109 - all had marked locations where a person could step, everywhere else was off-limits.

Here are some cutaways to compare structure:

P-51D

P-47C

P-40 (early)

F4U-1d

Spitfire Mk.1

Bf109G

FW190A-8

A6M "Zero"

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Lunatic

RG_Lunatic:

If I undertand you correctly, the P-47 had a thicker skin than the P-51 right?

Does anyone know how thick the aluminum skin on any fighter arcraft was?

I have never seen the two aircraft side by side but am aware of the dimensions / weights and agree that the Thunderbolt was a big boy.

I assume you are of the opinion that the Thunderbolt had a thicker skin as well.

I have seen and physically explored a TBF Avenger, another quite large plane, and was quite struck at how really thin its aluminum skin was.

At any rate, does anyone have any information on the thickness of the aluminum skin on any WWII aircraft?

DAVIDICUS said:

RG_Lunatic:

If I undertand you correctly, the P-47 had a thicker skin than the P-51 right?

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I think it did, but I really cannot say so "for sure". What I've read is that the P-47 had the thickest sheetmetal of any WWII fighter. So the P-51 sheetmetal might be equal?

DAVIDICUS said:

Does anyone know how thick the aluminum skin on any fighter arcraft was?

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I believe the P-47 used mostly 16 gauge (0.051") duraluminum where most planes used about 20 gauge (0.032") to 24 gauge (0.020") sheeting. Most planes used thicker sheeting in some places (leading edges of the wings for instance) than other places (side of the fusalage for instance). Note: the gauges I'm giving are based upon my observance of aircraft at airshows and museums and my limited experiance with sheetmetal (one job I had made its own cases for electronics and had sheetmetal cutting and bending equipment, and auto repair experiance). So these figures are only my estimates and should not be quoted as "fact".

Design Analysis of the P-47 Thunderbolt gives a lot of detail about the P-47 construction, but unfortunately does not give the skin thickness. Also of note on that site is Design Analysis of the Zeke 32 (A6M3).

Here's a very nice cutaway of the P-47D from the site listed above.

Drawing by Reynold Brown.

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Lunatic

RG_Lunatic said:

DAVIDICUS said:

RG_Lunatic:

If I undertand you correctly, the P-47 had a thicker skin than the P-51 right?

Click to expand...

I think it did, but I really cannot say so "for sure". What I've read is that the P-47 had the thickest sheetmetal of any WWII fighter. So the P-51 sheetmetal might be equal?

DAVIDICUS said:

Does anyone know how thick the aluminum skin on any fighter arcraft was?

Click to expand...

I believe the P-47 used mostly 16 gauge (0.051") duraluminum where most planes used about 20 gauge (0.032") to 24 gauge (0.020") sheeting. Most planes used thicker sheeting in some places (leading edges of the wings for instance) than other places (side of the fusalage for instance). Note: the gauges I'm giving are based upon my observance of aircraft at airshows and museums and my limited experiance with sheetmetal (one job I had made its own cases for electronics and had sheetmetal cutting and bending equipment, and auto repair experiance). So these figures are only my estimates and should not be quoted as "fact".

Design Analysis of the P-47 Thunderbolt gives a lot of detail about the P-47 construction, but unfortunately does not give the skin thickness. Also of note on that site is Design Analysis of the Zeke 32 (A6M3).

Here's a very nice cutaway of the P-47D from the site listed above.

Drawing by Reynold Brown.

=S=

Lunatic

Click to expand...

HEY, GREAT STUFF, LOVE THE CUTAWAYS!

Some info on sheet metal

Sheet metal thickness alone doesn't always mean the robustness of the structure. You could have .020 sheet metal made from 2024 material with what you call a T-3 temper and it will be harder to puncture than a 6061 sheet .032 thick in a T-3 condition. It also depends on what was behind the structure (corrugations, clips supports etc.) I would guess that both the P-47 and P-51 were both pretty similar in structure as sheet metal (even back in WWII) came in standard sizes and tempers. (.016 .020, .032, .040, .050, .063, etc.). You had to facilitate repairs on the entire fleet of Bombers and Fighters and the one thing you don't want is is non standardization of raw material. Aircraft sheet metal is always spoken in size, not Gage (that's for the air conditioning installers). For the most part, unless the structure had armor behind it, it was easily punctured. What mattered is how well that puncture held up with respect to the surrounding structure. The links that RG displayed clearly shows how much more robust the P-47 was built when compared with the Zero, but neither skin structure is going to stop a 50 cal round. Where the difference lies is the internal layout of the structure. For example, in the P-47 wing designers came up with an interior "box" which takes up much of the structural load. Compare that to the Zero that had conventional ribs and longerons and you could see the difference.

Today wing skins are made up of "planks" 7075 Aluminum with risers milled into them to support the structure. These planks are placed over wing ribs and held in place with rivet and hi-locs.

PS - Most Amercian aircraft constructed during WWII were made from 24T (2024 T3) aluminum

RG_Lunatic said:

By contrast, the Spitfire, the FW190, and the Bf109 - all had marked locations where a person could step, everywhere else was off-limits.

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If thats the case then explain these pictures:

AFAIK only some modern 'conserved' WW2 a/c's have these marked areas, as the owners really like them to stay that way.

Just because the surface is marked "Don't Step" doesn't necessarily mean you'll damage the structure if you step on it, its an area identified by the manufacturer where the possibility of damage or harm to personnel COULD happen if you step there.

I would guess at the front, as aircraft were being repaired, the NO STEP placard was the last thing the ground crews were worried about getting on the aircraft

Soren said:

RG_Lunatic said:

By contrast, the Spitfire, the FW190, and the Bf109 - all had marked locations where a person could step, everywhere else was off-limits.

Click to expand...

If thats the case then explain these pictures:

AFAIK only some modern 'conserved' WW2 a/c's have these marked areas, as the owners really like them to stay that way.

Click to expand...

You can see the footstep area on the FW wings Soren! Its the area just behind and inside the cannon bulge.

On that Spitfire, it's probably a plane going out of service, and besides that the fronts of the wings are strong enough for guys to sit on if they got up their without standing on the mid part of the wing shows nothing. Crawling or scooting up off a cart is not standing. The guys standing on the wing are standing on the wingroot area where it's okay.

What's the 109 pic supposed to show?