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And the Bonanza bladders are only a few mm thick though admittedly the access for the P-39 tanks is great. For the hose clamps access is a totally different story though.I watched a friend of mine putting a new bladder in a Bonanza wing.
I looked at the size of the bladder and the size of the holes and said, "You have GOT to be kidding me!" It looked like you were trying to stuff a football into a test tube. But it went in.
Bonanza bladders aren't meant to seal up bullet holes from high power rifles....And the Bonanza bladders are only a few mm thick though admittedly the access for the P-39 tanks is great.
The Ercoupes built right after the end of the war used "ternplate" which was steel covered with solder to make them easier to seal. They then went to Stainless Steel and then finally standardized on aluminum for the later models.
The P-38 drop tanks made in WWII were made from steel. There is a article I posted elsewhere here that described their manufacture.
A cube is the optimal rectilinear shape for minimal surface to volume area. 20" x 20" x 20" equals 8,000 cubic inches. If the self sealing wall thickness is 1/2" for ease of calculation, the interior volume is 6,859 cubic inches, or 86% of the external volume. All those little tanks would get heavy and small.To give an idea of volumn loss, take a sheetmetal box (of any size) and line it (sides, bottom, etc.) with 3/8" (10mm) plywood.
10mm is a minimum, the sealing material could be as thick as 1/2" (13mm) depending on the time, material and nation.
You'll find that the internal volumn of your box decreases quickly. You'll also find that the empty weight of your box has suddenly increased in weight considerably, too.
But much better than burning to deathTo give an idea of volumn loss, take a sheetmetal box (of any size) and line it (sides, bottom, etc.) with 3/8" (10mm) plywood.
10mm is a minimum, the sealing material could be as thick as 1/2" (13mm) depending on the time, material and nation.
You'll find that the internal volumn of your box decreases quickly. You'll also find that the empty weight of your box has suddenly increased in weight considerably, too.
Around 1998 I bought old inventory of a parts business and had maybe 8 bladders dated I think 1950? I think they were Goodyear. They had no cracks and I have them away and they were used as water toys. An old mechanic told me to install them there was a way to roll them coated with talcum then a sort of blower was placed and you inflated and deflated until they popped into place without a crease. Any crease would cause failure.Many of those bladders were made by Ball Band in Mishawaka Indiana, They also made Red Ball Jets! Ball Band eventually became Uni Royal, naugahyde!!
Self sealing tanks helped protect against rifle caliber projectiles and small fragments of AA shrapnel, not cannon rounds or large AA shrapnel (or approximate bursts).But much better than burning to death
Around 1998 I bought old inventory of a parts business and had maybe 8 bladders dated I think 1950? I think they were Goodyear. They had no cracks and I have them away and they were used as water toys. An old mechanic told me to install them there was a way to roll them coated with talcum then a sort of blower was placed and you inflated and deflated until they popped into place without a crease. Any crease would cause failure.
This was also a problem with self-sealing tanks installed in early F4Fs. The inner liner would break down, clogging fuel lines and resulted in crashes. It took a while to figure out what the problem was, because most planes were not recoverable.The Germans made what was one of the first non-metallic bag-tanks, for the Bf109F. I.e a flexible skin of synthetic rubber and fabric housed in a metal frame to keep the shape.
Sadly for them, they found out after a while that their version of 100 octane fuel reacted to the synthetic rubber (Perduren and Perbunan) and the fuel then lost its detonation resistance,
destroying the engine. It was incredibly difficult to investigate as the reaction took from 2 to 4 weeks, so aicrcaft "just filled" showed no symptoms at all, and aircraft taken on only very short trips showed moderate symptoms as the fuel in the tank was always "slightly" degraded. It was always a problem to a certain degree as the engines were always near the knock limit, and rarely were the fuel tanks totally dry, as then you dont even make it home, so degraded residue built up.