History

The F7U Cutlass seems destined to be remembered for its faults. The "Gutless Cutlass", as it came to be called certainly had its share of problems, but it also was an aircraft of remarkable innovation. The tricycle landing gear and pressurized cockpit were advanced features for the time. The Cutlass was the first production tail-less military aircraft, the first Navy aircraft with swept wings, the first production aircraft with afterburning engines, the first Navy aircraft with a high-pressure hydraulic system and, in the F7U-M, the first fighter to carry air-to-air radar guided missiles, the Sparrow I. In spite of its limitations most pilots found the Cutlass a joy to fly.

Willow Grove's F7U-3 is BuAer #129642. It was delivered to the Navy at NAS Oceana, VA, from the Vought plant at Dallas, in September 1954. During its brief career, #129642 was operated by fighter squadrons VF-81, VF-83, and attack squadron VA-12, before being flown into Willow Grove for the May 1957 airshow. Once at Willow Grove, the decision was made to retire the aircraft. It was given over to the Navy Reserves as a ground training airframe, and eventually made its way to static display in front of the base along Route 611. Total flight time on this particular airframe came to only 326.3 hours since new. Of 288 Cutlasses built, #129642 is one of four known to survive today.

The Chance Vought F7U "Cutlass" was the result of a 1945 US Navy request for a high performance jet fighter capable of 600 mph speeds at 40,000 foot altitudes.

In June of 1946, Chance Vought Aircraft won the contract. The Navy described the winning design to the public as an "experimental, tail less fighter designed for carrier operations and equipped with two 24C turbojet engines."

The principal features included swept wings, tricycle landing gear, pressurized cockpit, and armed with four twenty millimeter cannons. Specifications that were radically new were the requests for the four cannons and the tricycle landing gear. In 1946, very few aircraft had such a thing as a nose wheel. Most aircraft still had a tail wheel, straight wings and were unpressurized. Much of the technology used in this new design evolved from allied technical evaluations of German aircraft following W.W.II.

The F7U was the first USN aircraft designed with swept wings. Its delta shaped wing design featured radically different control surfaces than any seen before. Aileron functions joined with horizontal stabilizer functions. The resulting control surfaces became known as "elevons." The Cutlass featured twin vertical stabilizers and rudders. The tailless design demanded a critical center of gravity. A result was the need for an unusually long nose strut giving the aircraft a very high angle of attack for takeoff.

Power in the prototype was provided by two Westinghouse J34-WE-32 jet engines, each with afterburner, and mounted side by side in the rear of the fuselage. The pilot was given a pressurized cockpit and an ejection seat. The F7U was designed for more powerful engines than it ever received. Early jet engine technology was to evolve many years before engine thrust exceeded the aircraft's weight.

The J34 engines were found to provide much less power than was needed to make the F7U safe to fly, much less a potent fighter. The aircraft design was quickly changed in favor of the more powerful J46 jet engines. Although the F7U-3 version of the "Cutlass" first flew in December 1951, a lack of J46 engines kept the first F7U-3's from reaching service until the fall of 1954. Even the initially promising J46 design proved a disappointment. The J46 design promised 10,000 lb. static dry thrust in afterburner, but delivered less than half that. The J46's had a very high maintenance time to flight time ratio. These engines wore out quickly, and resulted in a great deal of down time for the aircraft. Unfortunately for the F7U, altering the design again to adapt to more powerful engines was out of the question. Aircraft engine technology was evolving too quickly for airframe designers to keep up.

During 1955, production was canceled in favor of the newer and far superior F8U "Crusader". Poor engine thrust often resulted in the loss of aircraft. The F7U was so under powered that the pilot's manual strictly forbade single engine approaches to carriers. Instead, the emergency instructions called for altitude, if possible, and ejecting, hopefully to safety. The "Cutlass" was simply too dangerous to risk a single engine landing.

As serious as the lack of power was, a more serious design deficiency existed in the form a weak drag link brace in the nose landing gear system. The unit frequently cracked during shipboard arrested landings, causing the nose gear to collapse violently. You will remember that the aircraft was designed with a high angle of attack, to facilitate more lift on takeoff and landing. The nose of the aircraft dropped about fourteen feet when the nose gear collapsed. Almost invariably, the pilot was critically injured or killed.

During the short service life of the F7U, deploying squadrons would typically fly most of their aircraft to shore bases in the vicinity of the ship, leaving only a few "Cutlasses" aboard ship for fleet defense and carrier quals. The risk to pilot and aircraft was reduced, and squadron commanders could sleep easier. A technical change was later introduced that strengthened the nose gear by 30 percent.

The twenty millimeter cannons were mounted two to a side, just above the engine air intakes. Both engines had an alarming tendency to flameout when the guns were fired. Initially, the problem was thought to be caused by ingestion of gun gases, but was later proved to be caused by a pressure resonance phenomena. When both sets of guns fired simultaneously, a pressure wave was created at the engine intakes. This pressure wave caused an organ pipe type resonance which then traveled to the aft section of the engine's compressor, creating a stall condition. The resulting air mass led the compressor blades to over temp, perhaps causing the engine to either burnout, or disintegrate. The problem was later solved by installing circuits that prevented the left and right pairs of guns from firing simultaneously, but not before an number of aircraft and pilots were lost simply by firing their weapons at a target.

Despite a poor accident record and excessive maintenance needs, the "Cutlass" was nevertheless popular with pilots, who found the aircraft seemingly unbreakable in "high - g" maneuvers, exciting to fly, and an excellent aerobatic machine. It was very comfortable, and in flight, possessed excellent visibility. The F7U-3 was the first fighter armed with the Sparrow I missile, and the first fighter to exceed the speed of sound while delivering weapons in a diving attack. It was also the first Navy aircraft to have a high pressure, 3,000 psi hydraulic system. The F7U-3 easily outmaneuvered the F9F-5 "Panther" and the Navy's version of the F-86, the FJ-2 "Fury." One man who test flew the F7U-3 was Lt. Wally Schirra, who later became a US astronaut.

In stark contrast to today's F/A-18 "Hornet", whose dimensions are roughly the same, the "Hornet's" engines provide triple the thrust, propelling the aircraft at twice the speed, with triple the F7U's weapons load.

F7U-3s equipped 13 fleet squadrons, four test squadrons, and one reserve attack squadron, VA-212 at NAS Moffett Field, California. The "Rampant Raiders" of VA-212 made one six month cruise aboard the carrier "Bonne Homme Richard", returned early in 1957, and traded their "Cutlasses" in for F9F-8 "Cougars." One VA-212 "Cutlass" survives today, restored and on static display at the US Navy's National Museum of Naval Aviation in Pensacola, Florida. The Marines operated only two F7U-3's from MCAS, Miami. Now Coast Guard Air station, Opaloka, Florida

Aircraft Specific Links:

• Aero-Web F7U-3
• F7U-3 Ejection Seat
• Aircraft Carriers F7U-3 photo page
• Vought Aircraft.com F7U-3 site