Wildcat Self-Sealing Fuel Tanks

[bamaackbar]

My understanding is that the Wildcat as originally designed did not have self-sealing fuel tanks but that these were added during production. Does anyone know if this is true and when specifically the self-sealing fuel tanks were added to the design? I am trying to determine if the addition of the self-sealing fuel tanks was the result of the U.S. Navy's observations of British experience.

 

[Thumpalumpacus]

My understanding is that the Wildcat as originally designed did not have self-sealing fuel tanks but that these were added during production. Does anyone know if this is true and when specifically the self-sealing fuel tanks were added to the design? I am trying to determine if the addition of the self-sealing fuel tanks was the result of the U.S. Navy's observations of British experience.

I'd have to dig up my copy of Lundstrom to be certain, but I'm pretty sure the factory changeover started in late 1941. Liner kits were sent to Noumea to upgrade the F4F-3s already flying from Lexington and Yorktown before Coral Sea, but I can't say when the planes started rolling out the factory doors so-equipped without digging up the book. I believe USN started receiving them in late 1941.

It's a little late but I'll see if I can find it tomorrow. I believe the Wildcat design change to F4F-4 with SS tanks was starting to roll out late 1941, and yes, I think both the USN and USAAF were taking note of air combat in Europe well before then.

 

[Geoffrey Sinclair]

Martlet I had 136 imperial = 163 US gallons of unprotected tanks
F4F-3 had 144 US gallons of protected tanks when fitted, same as the -4 , the -3 had Self Sealing Cells "S.S. Cells not removed for ferry (only rear tank fuel tight without cell, gain in capacity 3 gallons)" as per the 14 August 1942 data sheet.

81 Martlet I July to October 1940, 2 F4F-3 in August 1940, then 76 November 1940 to February 1941, 95 F4F-3A and 10 Martlet II with fixed wings March to May 1941, 97 F4F-3 May to September 1941, 50 Martlet II with folding wings June to December 1941 (only 6 by end September), 1 F4F-4 in November and 4 in December 1941. The folding wing Martlet II I think were fitted with self sealing fuel tanks. The XF4F-4 first flew in April 1941.

There was another batch of 100 F4F-3 in 1943, the F4F-7 reconnaissance version with unprotected fuel tanks built in small numbers most months January to December 1942.

http://www.wwiiaircraftperformance.org/f4f/f4f-3-detail-specification.pdf

Contract 68219 covered the first batch of F4F-3, the XF4F-4 and the pair of XF4F-5, BuNos 1844 to 1897 and 2512 to 2538. Contract 75736 covered the next batch of F4F-3, the F4F-3A and F4F-4. John Lundstrom indicates the F4F-3A as built did not have self sealing fuel tanks.

Location of U.S. Naval Aircraft, World War II

Click on the day, month and year (e.g., 2 Feb 1942) to view the Location of U.S. Naval Aircraft report for that particular timeframe. NOTE: All of these records are unclassified or have been declassified. Due to the age of the records, type of typewriter font, and capability of current OCR...

www.history.navy.mil

Does not start until February 1942.

 

[bamaackbar]

Thanks for the information. Based on this info and Lundstrom (pg 12-14 in The First Team), it looks like the decision to install the self-sealing fuel tanks must have come between in 1941. Lundstrom says that the installation of the self-sealing fuel tanks on East Coast Wildcat squadrons began in late 1941. I don't suppose ya'll have insight into when in 1941 the decision to install the self-sealing fuel tanks was made? Thanks

 

[Shortround6]

Decision to install and actually installation may have have been months apart.

For the USAAC the decision to use self sealing tanks on P-40s was made in mid (?) 1940. But they used two different materials or methods on the P-40B and P-40C with different fuel capacities. In Aug 1940 the USAAC was ordering P-38s with armor. In Sept 1940 they were ordering P-39s with self sealing tanks.
It often took months for actual first deliveries to be made.




The Brewster Buffalo got some self sealing tanks on the F2A-3 model (F2A-2?) and things get a bit confusing. The US installed 3 new tanks with self sealing and did not add any self sealing to the existing 2 wing tanks (5 tanks total) but the US blanked off one of the existing tanks and did not use it.
The F2A-3 was ordered in Jan 1941 but construction didn't start until June (delivery started in July).
F2A-3 also had a CO2 Purge system for the existing wing tanks.
British Buffalos (339E) got light armor in front of the existing wing tanks and Linatex and horsehide leather to provide some sort of self sealing.

F4F-3A's may have been built mixed in with the F4F-3 production due to an engine shortage of the two stage engines. Start of production specifications may not have been end of production specification/equipment fit. US refitted a number of existing aircraft.

 

[RCAFson]

My understanding is that the Wildcat as originally designed did not have self-sealing fuel tanks but that these were added during production. Does anyone know if this is true and when specifically the self-sealing fuel tanks were added to the design? I am trying to determine if the addition of the self-sealing fuel tanks was the result of the U.S. Navy's observations of British experience.

This is from Lundstrom, First Team, Volume 1:

Fighting Forty-two's precarious situation vis-à-vis its aircraft worsened on 7 April. That day the nagging problem of the self-sealing fuel tanks blossomed into a real crisis, especially since the enemy was not all that far away. As Fletcher later put it, the fuel tanks began "going sour."9​ One Grumman after another was laid up because of disintegrating tank liners, and by 10 April, no fewer than seven out of the nineteen F4F-3s were inoperable. For the rest it was only a matter of time. Flying them was an experience not soon forgotten: "fuel seepage through the outer skin [of the tanks] made for scary smells."10​

The squadron's troubles stemmed from a particular batch of self-sealing fuel tanks installed the previous December in place of the vulnerable aluminum tanks. The bladderlike tankage, made up of rubber layers reinforced with cloth, had swelled and split its seams, while the inner linings had blistered, sloughing-off pieces of material. Naturally these particles could raise hell with a fuel system, jamming fuel strainers and plugging lines, behavior that VF-42 felt explained a number of plane losses. The "cemented" type of tank, especially, turned out not to be suitable for the aromatic aviation gasoline used by the fleet, as the fuel tended to dissolve the glue and rubber making up the tanks! Owing to poor seals at the filler neck, gasoline sometimes dripped on the outer skin of the tanks, eating away at them from the outside as well. ComCarPac's materiel officer reported similar problems with F4F-3s in other squadrons.

Even if Brassfield's engineers knew what caused the deterioration, they had no way of repairing the damage. On 10 April (the same day the ship raffled off the last steak on board), Fletcher informed CinCPac of the trouble with VF-42's fighters. Meanwhile, Task Force 17 patrolled back and forth across the center of the Coral Sea. On 14 April, with the seven inoperable F4F-3s essentially unrepairable on the spot and no telling how long the rest would be flyable, he advised Nimitz of his intention to withdraw to Tongatabu if any more fighters turned "sour." Rightfully he felt the lack of fighters crippled the task force's ability to defend itself. The only recourse was to replace all of the tanks with the vulcanized variety and ensure proper sealing at the filler necks.

Fletcher's message crossed one from Nimitz stating that he had resumed operational control over Task Force 17. CinCPac told Fletcher to retire to Tongatabu for necessary supplies, then depart there on 27 April once again bound for the Coral Sea. The new orders ended the offensive patrol, and on 15 April Task Force 17 started southeast toward New Caledonia and points east. The next day another Wildcat succumbed to bad tanks, justifying Fletcher's caution. He radioed Pearl requesting immediate air shipment of twenty-two F4F-3 self-sealing fuel tanks (enough for all fighters and three spares) from Oahu to Tongatabu. CinCPac had already made arrangements to transport the vitally needed replacements to Suva in the Fijis and replied that Fletcher should send a destroyer to bring them to Tongatabu.

On 20 April, Task Force 17 took its first really close look at a South Pacific isle. That morning the Yorktown flew two SBDs and two TBDs to the airstrip on Tongatabu and later dropped anchor along with the rest of the task force at Nukualofa Roads off Tongatabu. Here was the haven where the ships would refuel, reprovision, and relax before again returning to enemy-threatened waters. Already in port were the provision ship Bridge, the repair ship Dobbin, and the hospital ship Solace. Pederson put two F4F-3s on alert, to be shot off from the hangar deck catapults in the unlikely event the Japanese showed up. Fletcher despatched the destroyer Walke the 400 miles to Suva to fetch the replacement tanks. For many of the crew, there was liberty during daylight hours, and that helped restore some good humor to those who had signed on to "see the world." The small New Zealand garrison was most friendly to the Yanks, but beguiling young South Seas maidens were nowhere to be seen. Their Queen Salote had ordered them to hide in the hills!

The Walke returned on 22 April with the first batch of tanks flown down from Pearl Harbor. Brassfield and his machinists set to work installing them in the Grummans, a thankless task indeed. For each fighter, they had to remove access plates and over 500 screws, then push and pull the troublesome bladders into place, taking about 20 man-hours per plane. The second shipment of tanks reached Suva on 22 April and soon were brought to Tongatabu. Thus VF-42's F4Fs finally became fully airworthy, thanks to the emergency transport of vitally needed components and the unceasing labor of the squadron engineers.(11)​

So the SS tanks began to be installed in Dec 1941.​