The Crazy Aircraft Carrier Hangar Catapults Of World War II

The Crazy Aircraft Carrier Hangar Catapults Of World War II 

by Tyler Rogoway, TWZ Newsletter, 5 July 2020 

Click on the link above to view the full article. 

"The idea was novel, but far from a long-lived success."

"It sounds nuts to begin with right? But before the angled deck was introduced, aircraft carrier designers had to figure out how they could quickly launch a scout aircraft even when the straight deck flattop was a chaotic mess or undergoing recovery operations. So the idea was to put a catapult that ran across the beam of the ship down in the hangar bay, with big doors on each side. This way, a scout plane or two could be launched in a pinch when the top deck was fouled." 

 A F6F-3 Hellcat ready to be launched by the USS Hornet (CV-12). (US Navy photo)

 

 A Grumman F6F-3 Hellcat of VF-15, launched by USS Hornet (CV-12) on 12 February 1944 when the ship was located in Chesapeake Bay. (US Navy photo)

 

 The same F6F Hellcat as above during its side launch. (US Navy photo)

 

F6F belonging to VF-1 seen on the USS Yorktown (CV-10) main deck. Below, the ship’s hangar catapult is clearly visible. (US Navy photo)

 

A Grumman TBF-1 Avenger of VT-5 launched by the USS Yorktown (CV-10). (US Navy photo)

 

Some additional info on the cross deck catapult in the USN.

The cross deck catapult on the hangar deck goes back to the early 1930s and the design of the USS Ranger CV-4, albeit that they were never fitted to her as an economy measure. Subsequently, Yorktown CV-5, Enterprise CV-6 and Hornet CV-8 each received a hangar deck H-2 model catapult as well as two of the same model on the flight deck. Wasp CV-7 received two such hangar catapults as well as two on the flight deck. At that time catapults were little used as aircraft were relatively light weight but even less use was made of those on the hangar deck (Enterprise used hers three times in 1941 out of 21 catapult launches total). On 17 February 1942 their removal was authorized, and by June 1942 that had been done on Enterprise and Hornet. Yorktown retained hers when sunk. I don’t know about Wasp, but she did receive a short refit in May/June 1942 before departing for the Pacific so their removal is possible.

The Essex class were designed in 1939/40 with an H4A catapult on the flight deck and an H4B on the hangar deck. Equipment shortages saw Essex complete with none. She received a flight deck catapult only before deploying to the Pacific in mid-1943. Lexington CV-16 also only got the flight deck catapult at completion.

The six that received the hangar deck catapult were Yorktown CV-10, Intrepid CV-11, Hornet CV-12, Franklin CV-13, Bunker Hill CV-17 and Wasp CV-18. As these ships came in for refits and damage repairs in 1944/45 the hangar deck catapults were removed and a second catapult installed on the flight deck, so bringing them into line with later completions.

Those Essex class completing from the beginning of 1944 had the hangar deck catapult replaced with a second flight deck catapult.

As aircraft weights increased the hangar deck catapults were found to be of less and less use since there was no additional benefit from the wind over the deck generated by the ship’s speed through the water to aid the launch. Hornet CV-12 was the last to lose her hangar deck catapult in her June-September 1945 refit.

In the pre-war British aircraft carriers (Furious, Courageous and Glorious) and the Japanese Akagi and Kaga there were no catapults at hangar deck level to assist aircraft in taking off. All takeoffs from the hangar deck level in these ships were unassisted. As aircraft grew in size and weight this became impossible. So the Japanese rebuilt their ships to eliminate the feature in the mid-1930s.

In Courageous and Glorious the lower flight deck wasn’t used after 1935 and the doors welded shut. Furious’s forward hangar opening was plated in as part of her 1938/39 refit.

Incidentally, no Japanese carrier was equipped with a catapult.

Catapults only reached Royal Navy carriers with the completion of the conversion of Courageous in 1928. Of the earlier carriers only Argus ever received one before being either sunk or retired. 

from EwenS on the Secret Projects forum 

A diagram of an Essex showing the location of the hangar catapults.

 

HMS Furious with lower flight deck in action in the 1920s.