The Zero - Self-Sealing tanks?


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22 June 2008
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...According to comments from someone on another forum, the Jap Zero's main weakness was that its fuel tanks were not "self-sealing", and that once hit they leaked profusely. Was this actually the case, and can anyone provide info on just exactly how the self-sealing tanks on Allied planes during the period worked?

(Yeah, the Zero isn't a secret project per se, but it was until the TAI was recovered in the Aleutians)
Most sources suggest that protected fuel tanks were introduced with the A6M6c. Prior to that model, fuel was carried in non self-sealing, welded aluminum tanks.

IIRC, the first attempts at self-sealing tanks consisted of wrapping the tank in cord (the idea being that the sisal would swell when wet). Tank interiors could also be lacquered, shellacked, or lined with wax.

In WWII, most self-sealing tanks were metal covered in rubber compounds like Plioform and Eliolite or synthetics like as neoprene or thiokol. Same idea though. The rubber would swell when exposed to leaking fuel.

Other WWII tanks were flexible bladder tanks (RB Gray & JC DeWeese, Patent 2381739, 1941) where the 'bag' was slipped inside the metal tank (or wing structure). The bag's flexibility was meant to lessen the chance of puncture in the first place.
ı think ı read that late model 'M5s had self sealing tanks as well , but ı can't offer a source . And ı have also read the German way of using real leather in building the tanks was grossly inefficient way to achieve safety but a great way for getting nice clothes once the plane was discarded .

edit: At home ı checked the book ı was reading and ı see it was indeed the M6s that had self sealing tanks ; at the end of a long paragraph about '5s , ı have misread it
Yes, self-sealing fuel tanks are basically rubber bladders that are 'self-repairing' by swelling when punctured. I'm not sure if swell by contact with fuel is the only way they work though, but that would probably be the most common method at least during WWII.

I know at least on GA aircraft you either had actual bladders on the wing or the fuel cell was lined with a self-sealing material, like said on above. But since you don't go flying into flak in a Cessna all that often, and since the bladders cut down on total fuel capacity, they went back to just a "wet wing" approach where only panel joints are sealed (though this means that some of that sealant can wear, break loose and clog the fuel lines, which may have been the original justification for the bladders in the first place, IIRC).
OM said:
(Yeah, the Zero isn't a secret project per se, but it was until the TAI was recovered in the Aleutians)

A6M's had been recovered, repaired and flown in China previous to Pearl Harbor. An example was actually boxed up at Rangoon for onward delivery but no one had any official interest. If I recall correctly, this aircraft was rebuilt by Gerhard Neumann of later General Electric and turbofan fame. See Bill Gunston, Plane Speaking, Patrick Stephens Ltd., 1991 ISBN 1-85260-166-3. This includes a photograph of the said aircraft, complete with non standard cooling gills that Neumann had manufactured to complete the repair. There is a lot of post December 7th rubbish still going the rounds to disguise how much was actually known and ignored about Japanese equipment, capabilities and intentions ante-bellum.
The RAAF also recovered a pristine Zero in early 1942 on Melville Island that had been shot down by a lucky bullet piercing the oil tank. If that wasn't enough the Chief Designer of the Australian Commonwealth Aircraft Corporation (CAC) Fred David had worked for Mitsubishi as an engineer on the Zero for two years before moving to Australia. David was a refugee from Germany where he had been an engineer for Heinkel. David and his boss Lawrence Wackett proposed building an improved Australian Zero as early as 1939 but were turned down by the RAAF who believed that only twin engine fighters would be effective in long range Pacific operations and wanted the Bristol Beaufighter.
Abraham Gubler said:
David and his boss Lawrence Wackett proposed building an improved Australian Zero as early as 1939


Do you have any more info on what this improved Australian Zero proposal?


Some earlier discussion on the Aussie Zero concept.,5039.0

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