The Ryan FR-1 Fireball and F2R Dark Shark: An Evolutionary Dead-End

When the US Navy initiated the development of its first jet fighter, the McDonnell FD-1/FH-1 Phantom, in 1942, not only did it hedge its bets on McDonnell's design by carrier testing the Lockheed P-80 Shooting Star, but it also initiated a back up program at the insistence of the Navy's Bureau of Aeronautics (BuAer) for a mixed-powerplant fighter that combined a conventional piston radial engine with a jet engine. There were still a lot of unknowns about the operation of jet aircraft from fleet carriers and the concept of a mixed powerplant fighter would combine what was known- that a conventional radial engine had the performance for a carrier takeoff and a wave-off from landing and that a jet engine could provide a boost for high speed performance. At the same time as the start of the FD-1/FH-1 program, BuAer held a competition for a mixed-powerplant fighter which was won by San Diego-based Ryan Aeronautical Corporation which started work in 1943 on the prototype for the FR-1 Fireball.

Ryan FR-1 Fireball
(Wikipedia)

The Fireball's radial engine was a Wright R-1820 Cyclone 9-cylinder radial engine generating 1,425 horsepower. The R-1820 was used on a variety of World War 2 aircraft from the Boeing B-17 Flying Fortress to the Douglas SBD Dauntless and Curtiss SB2C Helldiver. This was a surprising choice given that the standard engine of the Navy fighters of the day was the 2,000 horsepower Pratt & Whitney R-2800 18-cylinder Double Wasp. The jet engine in the rear fuselage, fed by wing root intakes, was a General Electric I-16 (later redesignated J31) developing approximately 1,600 lbs of thrust. The I-16/J31 was a GE production version of the Whittle W.1 centrifugal flow turbojet and was the first production jet engine built in the United States. Outside of the Fireball, two of the same jet engine were used on the Bell P-59 Airacomet. Development of the three prototype XFR-1 airframes proceeded along remarkably smoothly and the prototype made its first flight on 25 June 1944 powered only by its piston engine. On the third flight, the I-16 engine was fitted to the prototype and used successfully.

The Fireball boasted excellent cockpit visibility but one of its other unique features was it was the first production carrier-borne aircraft to have a tricycle landing gear. This was done primarily out of necessity to elevate the jet engine exhaust up and away from the wooden decks of the Navy's fleet carriers. Despite the loss of the three prototypes, the Navy was anxious to field the FR-1 Fireball and had already ordered 100 aircraft a year before the first flight of the prototype. With satisfactory flight testing and excellent performance, another 600 aircraft were added to the order in 1944. The Navy wanted the Fireballs in the Pacific as a Kamikaze interceptor- Fireballs were planned to be used in combat air patrols, loitering on their radial engines. When inbound Kamikazes were detected on radar, the Fireballs would light up the jet engine and speed off to intercept the enemy. At the end of 1944, the Navy ordered 600 of a faster variant, the FR-2, that had a more powerful R-1820 engine that developed 1,500 horsepower. 

VF-66 Fireballs in formation flight
(San Diego Air & Space Museum Archives)

Navy fighter squadron VF-66 stood up at NAS North Island where the Ryan plant was located to speed the introduction into service of the Fireball. Instead of the usual operational evaluations and demonstrations, VF-66 was tasked to get the Fireball into action as soon as possible. Unusual for a Navy squadron of the day, VF-66 was made up of senior officers and experienced pilots. Five days after VF-66 stood up on New Year's Day 1945, the first FR-1s were making their initial carrier qualifications aboard the USS Ranger in preparation for combat deployment. The squadron pilots enjoyed flying the FR-1 for its speed and maneuverability. Pilots often would make low passes at area airfields with the front prop feathered to confuse tower and airport personnel. By July 1945 VF-66 was in final preparations to take the FR-1 into combat but it was all for naught when the Pacific War ended the following month with surrender of Japan after the atomic bombings of Hiroshima and Nagasaki. The Fireball was officially unveiled to the public in September 1945 but only 66 FR-1s were produced and delivered before the war ended, the balance of orders for the FR-1 and FR-2 being canceled. After the war in November 1945 a Fireball that suffered a radial engine failure landed on the USS Wake Island to be come the first jet landing on an aircraft carrier, but obviously not intentionally!

Looking to improve the Fireball's performance, Ryan proposed the FR-3 that would have taken the faster FR-2 design and swapped out the I-16 engine for a more powerful GE I-20 engine that offered 2,000 lbs of thrust. The FR-3 never got built, but Ryan did a contract for a prototype of the FR-4, which used a 3,400-lb thrust Westinghouse J34 engine in the rear fuselage. The XFR-4 did fly, and the main external difference was the relocation of the jet intakes from the wing roots to the lower sides of the nose just aft of the radial engine. Doors could close off the NACA-style flush intakes to keep the jet engine from windmilling and producing drag and small eyelid doors could increase the area of the intake as well. The XFR-4 added 100 mph to the top speed of the Fireball, but only one prototype was built. The small number of FR-1s, however, were withdrawn from service when in 1947 they were found to have significant structural fatigue in the aft fuselage just behind the wings. The last flyable FR-1 arrived at the Naval Air Technical Training Center in Memphis, Tennessee, to be used as a maintenance trainer.

Ryan F2R Dark Shark configuration
(San Diego Air & Space Museum Archives)

It wasn't the end of the road for the Fireball just yet, though. The Powerplant Division of BuAer still remained skeptical of the performance of jets in the carrier landing pattern. Ryan was asked to further develop the FR-1design by replacing the radial engine with a General Electric 1,700-horsepower XT31 turboprop engine. The XT31 was the first turboprop engine designed and built in the United States and was also used on the Air Force's Convair XP-81 turboprop/jet fighter. The new Ryan fighter was designated the F2R Dark Shark and though it retained the wing root intakes and the I-16/J31 engine of the FR-1, it had an impressive climb rate but lacking the drag-reducing jet intakes of the FR-4, it was actually slower than the XFR-4 in level flight. With the large 8-foot prop, the Dark Shark demonstrated improved performance in the carrier landing pattern over the FR-1, but by the time of its first flight in November 1946 McDonnell had proven the practicality of pure-jet carrier operations with the FD-1/FH-1 Phantom and the last resistance within BuAer to pure jets had ended as the Navy decreed that all future fighters after the Grumman F8F Bearcat would be pure jets.

The Dark Shark in flight
(San Diego Air & Space Museum Archives)

The Air Force (then still the USAAF) was impressed with the performance of the XF2R-1 Dark Shark prototype and asked Ryan to make some modifications to evaluate it in competition against the Convair XP-81. What was designated the XF2R-2 featured the NACA flush intakes on the nose of the XFR-4 feeding a Westinghouse J34 engine. The XF2R-2 was ultimately never built other than as a mockup, as the Air Force decided, like the Navy, that mixed powerplant fighters were an evolutionary dead end and the future lay with pure jets.

I should also mention the Curtiss XF15C which was also planned as a Navy mixed-propulsion fighter. But that aircraft will be getting its own article at a later date here at Tails Through Time!

Further reading: 

The Coming Kamikaze Threat in World War II We Never Faced
Refining Anti-Submarine Warfare: The Grumman AF Guardian
The Ground-Breaking Gun Turret of the Grumman TBF Avenger
The Boeing PBB Sea Ranger: The Best Flying Boat at the Worst Possible Time

Source: U.S. Naval Air Superiority- Developement of Shipborne Jet Fighters 1943-1962 by Tommy H. Thompson. Specialty Press, 2008, p28-30.