how were belly tanks made?

P-38 belly tanks. How were they made originally? Stamped? I'd imagine if they were stamped it would have to be done in a few stages seems like a pretty deep draw. What alloy of aluminum were they made out of? anyone have pictures of them being produced?

 

I wanna know, too.

 

Stamped by big**** machines.. Lucky

 

They could be hydroformed.

 

i'm listening...
i'm interested too.

 

care to elaborate a bit on that Lucky?

 

Imagine a male and female giant die. I seen an article about it. I've seen pictures of these giant stamping machines. Unfortunatly most were destroyed as they were to big to move.

 

I've seen huge stamping machines for automotive parts. Dearborn Deuce has a GIGANTIC press. I was more interested in the details, single stage stamping? alloy used? and damn someone on here has got to have some pictures of production.

 

I bet they were spun.

 

they have a seam down the length of them Like two identical halves riveted together

 

Ive seen the tanks in pictures never put my hands on one. Just my 2 cents

 

Not spun. I've put my hands on a couple of them. Plus it wouldn't lend itself well to rapid mass production.

Pretty sure they're stamped in some manner. Keep in mind the center sections on some of them can practically just be a rolled sheet, there doesn't have to be a lot of stretching except at the nose and tail. But that's about all I know.

Anybody else?

 

Believe it or not some P51 & Thunderbolt drop tanks were made out of laminated cardboard. Thats no*****. Probably couldn't get one thru tech at Bonneville. Info from AAF P47 group logs. Mar1, 1943,-Us made resonated paper P47 belly tanks arrive in the UK, but are not satisfactory. They leak,will not feed at high altitude, and cannot be pressurized.... Sept 1943.- UK locally produced 108 gal paper fuel tanks are now being delivered in increased quantity. These tanks give the P47 an******* radius of about 375 m.... A mention of 75/85 g steel tanks, states " 10 thousand are being shipped from the US". They must have worn the dies out on that run.

 

Read what Bobby Green said ,he is dead right.He owns several and knows alot about the history of the things.
Mine is Stamped Sheet metal about 14 guage steel,there was internal ribs and fittings made from moly tubing inside mine.Yes a few were made from resin impregnated paper,but few of those still exist,if any.

 

Beer and fast food

 

It would be interesting to know if they were made by an aircraft company or farmed out to another industry during WWII. I've read they have a heat treat that makes welding on them very difficult. Are they mirror image or are there tops and bottoms?

 

I have seen alot of wartime photos of tanks and refueling processes and equiptment while researching airplane projects and the finish on the tanks wasn't always that great, Lots of long scratchy tooling marks running from top to bottom and somewhat wavey surfaces. That would seem to support the notion that they were stamped out quickly and to a pretty basic degree of finish. You can stamp out some really big parts efficiently if you dont have to achieve perfection. All my warbird friends would love to get thier hands on the appropriate tanks for thier planes but complain that the hotrodders have got them all stashed in the rafters of our barns... news to me.

 

Not sure about all designs but some had different tops and bottoms to account for aero differences between tank/wing and tank/more open air below.

 

Some of the P-38 tanks were also made of wood, by casket makers. The was a lot of improvisation done back then.

 

There were one way tanks right? I don't think they'd want to risk landing with that thing under them.

 

Most of the tanks ive seen are formed (stamped or hydroformed) and welded at the seam. Aircraft tanks are usually made of 30xx or 51xx aluminum. These alloys are very malable and weld well. Ive also seen tanks with a flange and rivets/bolts to hold the halves in position. Plz dont try to make a b'ville racer from a cardboard tank.

 

Belly tanks and wing-tip tanks were similiar. When I worked at the Alameda Naval air
Overhaul Facility,in the late 50s, they used to repair them. when finished, they would test them with air pressure. The Machine shops that I worked in were in the same hangar as the tank repair shop. I will always remember the day one exploded.

 

I'm wondering why some folks don't thinmk one of the "cardboard" tanks would work at Bonneville. Remembger that the cardboard or paper was used as filler for a polyester type resin. If you substitute fiberglass for the cardboard, you would have what is available today.
Not strong enough? Just remember, the tanks were mounted on fighters that were flying at 300+ mph. Should be plenty strong enough for most tank classes.

 

The 37 Kid talks about farming things out. Take your mind back to 1940. Yes, even before me. Just coming out of depression, everyone was trying to get back to making something. Everyone who had manufacturing capacity was called on to build for the coming war. I once looked down in the valley of an Allison V12. The intake manifold had the familiar Maytag logo. Maytag could cast and machine small aluminum parts, and they did.

 

I work in a stamping facility making steel parts for cars. The process for making parts has changed very little in the last 100 years or so. I will try to explain how it works.

A draw die (the first one in the process) is made of 3 parts. the sheet of metal is set into the die and clamped between the upper (female) half of the die & the part called a blank holder - basically a cast steel ring that fits around the perimeter of the lower die punch (male half). depending on the metal being formed, the size of the part and the depth of the draw this clamping force can be upwards of 20 tons. the sheet is then stretched (drawn) over the male half of the die and turned into a part.

There are usually other dies in the process. usually the second die will trim excess metal from the edges of the part and the third & fourth dies will punch any needed holes in the stamping.

Depending on the production needs different typed of presses are used. For low volume production runs a smaller press that will only hold one die at a time is used (such as the dearborn deuce press) The first die is loaded & 200 draw panels are made. Then the second die is loaded & those 200 panels are stamped through the second die. Then the third die is loaded etc. For mass production a larger press is used. For instance the press that I run has a capacity of 2500 tons of force and can make up to 25 panels a minute when it is wound right up. This press has a footprint of almost 100 feet long, about 25-30 wide & from floor level to the top of the press is almost 40 feet. There is another 15 feet of it hanging below the main floor level into the basement. For comparison the dearborn press is about the same size as the 800 ton press in our plant. Not sure how much force the dearborn press can put out but physical size is about the same.

I will try to get some pics of it in action and maybe a couple of short videos when I get the camera charged. Here is a pic of the press to give an idea of the size of the beast.

 

We look at WW2 combat aircraft and parts as beautiful art and mechanical wonders of their day.But it was war,they were machines of death,everthing mechanical was disposable in war.The only concern was for the pilot and or airmen.

 

Thanks Toner283, if I had a better camera I'd post the photos of the tooling it took to make the dies to stamp late 1930's GM roof sections. A clam model was made and a tracer would use this to cut the dies. This whole process started when the White Sewing machine company figured out how to stamp out bathtubs.

 

http://home.earthlink.net/~charlesfelton/id19.html

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Here is some 108gal paper tanks.
Remember P-51D's went nearly 400 MPH, and that was in level flight.


this is perfect for a bellytanker and was still on the pole as of '06.

 

Tanks I have seen came in top and botton parts. the top having the mounting brackets to join the pylon. When they made Bonneville tanks they would use two bottom sections. And yes many of them were pretty rough. remember theey were made to be dropped in combat. No point in making a really pretty tank that is going to be dropped into Germany.