29 October 2010

How the Lockheed P-80 Saved McDonnell Aircraft

In 1942 James McDonnell was summoned to Washington to meet with officials from the US Navy's Bureau of Aeronautics (BuAer). At the time McDonnell Aircraft only built parts for other aircraft manufacturers at its St. Louis facilities and only had one aircraft program going, the XP-67 Moonbat fighter. To McDonnell's surprise, BuAer asked McDonnell and his small team to design a carrier-based jet fighter. Not having had any prior experience worked in McDonnell's favor- the Navy felt that he was free of any bias or prejudices and was therefore most likely to come up with an innovative design. McDonnell's design would be come the FD-1/FH-1 Phantom, the first purpose-built carrier-borne jet fighter. But BuAer's decision was not without its controversy in the Navy and to satisfy the critics, it was agreed to evaluate an existing jet fighter that by that point was only a year from its first flight- the Lockheed P-80 Shooting Star, which first flew in June 1944. With a more powerful engine, the P-80 was faster than the FD-1 Phantom. In early 1945, the Navy purchased two P-80 Shooting Stars for evaluation, one of which would be suitably modified for evaluation as a carrier-borne fighter. 

The first Navy P-80 was flown from Lockheed's California facility to the Navy's flight test center at NAS Patuxent River, Maryland, incidentally becoming the first transcontinental jet flight on 29 June 1945 (though it wasn't a nonstop jet flight). The pilot was a young 1st Lt. Najeeb Halaby, at the time a US Navy test pilot who later on would become the FAA Administrator under JFK and later become CEO of Pan Am. The plan was to conduct shore-based trials first before going through with ship-board trials. Through 1946 the P-80 was flown in mock combat against the Navy's main fighter of the day, the Grumman F8F Bearcat. Though not as maneuverable as the Bearcat, the P-80 had the luxury of speed to engage and disengage in combat much to the Bearcat pilots' frustration. The second P-80 arrived at NAS Patuxent River in December 1945 after being modified by Lockheed with a tailhook, catapult hooks (for use with a catapult bridle) and a catapult shuttle holdback. Shore-based tests to simulate carrier operations were used to determine the operating parameters for the P-80 on the carrier deck. Catapult shots were easily accomplished on land-based gear, but it was found that the P-80 was exceptionally clean aerodynamically on approach and had to be "flown" onto the deck, but the nose gear design was too weak for a firm carrier-style three-point landing. But if the P-80 landed to hard on its mains, it would rock forward and the hook would miss the arresting wires. 

After more testing, the project pilot, the legendary Marine Corps ace Lt. Col. Marion Carl and his LSO managed to determine the proper approach speed (just 5 mph above the stall speed of the P-80) and flare to minimize the forward rocking motion on landing. Though the margin was considered too close to the stall speed, Carl found that the P-80 had good stall warnings well in advance of the actual stall. On 1 November 1946 Carl took the P-80 to sea aboard the USS Franklin D. Roosevelt. Catapult launches and arrested landings were made safely, but it was found that the P-80 needed 900 feet of deck with 35 knots of wind over the deck to take off without the catapult, over twice the distance the McDonnell FD-1 required. To put that into perspective, the length of the FDR's flight deck was just shy of 961 feet! It was also found that the J33 engine of the P-80 took as long as 2 minutes to spool up to full power after starting, which would greatly lengthen the deck launching cycle. From catapult takeoff, one circuit in the carrier landing pattern, and then an arrested landing, the P-80 used 37 gallons of fuel. By comparison, the Vought F4U Corsair only used 6 gallons. 

The next phase of carrier testing then involved flying the P-80 at operational loads which also included use of the tip tanks that were a fixture on USAF aircraft during the Korean War. It was quickly found that in this more realistic configuration the catapults of the day even with a strong wind over the deck were unable to launch the P-80. In addition, the wing structure where the tanks were attached was too weak and a stronger catapult would have just launched the P-80, leaving its tip tanks behind!

Before the carrier tests were performed, some in the Navy unhappy with BuAer's decision to go with McDonnell wanted to purchase the Lockheed P-80 Shooting Star instead. Lockheed even did some design work on what they called a P-80B for the Navy which would have had the Navy designation FO-1 (Lockheed's designator become V in the 1950s, so it would have been then known as FV-1). The deck trials quickly ended this proposal and McDonnell would go on to develop a whole line of fighters for the Navy from FD-1 Phantom, the F2H Banshee, the F3H Demon, the superlative F-4 Phantom II and today's F/A-18 Hornet. The Navy, did however, buy 50 P-80s to be used as shore-based trainers to allow naval aviators to gain jet experience. VF-6A (later renumbered VF-52) at NAS North Island and Marine squadron VMF-311 at MCAS El Toro operated the P-80s. Lockheed did, however, develop the TV-2 SeaStar based on the Lockheed T-33 in the 1950s. The T-33 required an extensive amount of modification to be suitable for carrier operation. In 1962 the TV-2 was redesignated the T-1 and was ultimately replaced by the North American T-2 Buckeye.

Source: U.S. Naval Air Superiority- Developement of Shipborne Jet Fighters 1943-1962 by Tommy H. Thompson. Specialty Press, 2008, p23-33.

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