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.

The Cadillac of the Constellation Line

Through the 1950s Douglas and Lockheed engaged in a rivalry to create the ultimate propliner as each company successively improved its product line to appeal to the rapidly expanding passenger market. Douglas' DC-6 led to the more powerful DC-7 and even with this aircraft, the design was pushed even further with the DC-7C. In addition to more power and fuselage stretch, the "Seven Seas" also had a constant-chord wing-root section added inboard of the engines. Not only did this move the loud radials five feet further away from the passenger cabin, it also increased the aspect ratio of the wing, reduced drag, and provided more space for internal fuel. The DC-7C could now outperform Lockheed's flagship propliner, the L-1049G Super Constellation, in terms of speed, range, and payload, allowing all-year round nonstop trans-Atlantic service. Not to be outdone, Lockheed briefly considered a turboprop Constellation, the L-1449, using the new Pratt & Whitney T34 engine (which was used on the Douglas C-133 Cargomaster). While military Constellations did flight test both the T34 installation and the Allison 501 turboprop (military versions of which were used on the C-130 Hercules and P-3 Orion), Pratt & Whitney balked at the use of the T34 as they felt Lockheed was pushing the engine too far. 

Scrapping the L-1449 out of the dispute with Pratt & Whitney, Lockheed took the new wing design it had developed for the turboprop L-1449 and grafted it on a stretched L-1049 Super Constellation fuselage to give birth to what many consider to be one of the ultimate piston engine airliners, the L-1649 Starliner. The wing was modified to accept the powerful Wright R-3350-18EA Turbo Compound radial engines which were originally developed to power the Navy's Lockheed P-2 Neptune patrol bomber. The 18-cylinder R-3350 instead of using a turbocharger for high altitude performance had power recovery turbines instead (PRTs)- one PRT collected the exhaust gases from six cylinders to deliver more power back to the engine crankshaft, providing a 500 horsepower boost. The same engines were used on the DC-7C as well. The long wing of the Starliner gave it the highest aspect ratio wing of any propliner, 12:1, and this translated to improved performance over the DC-7C. Nearly 2,000 gallons more of fuel could be carried compared to the Super Constellation. Like the DC-7C, the longer wing put the inboard engine nacelles further away from the passenger cabin. 

The Starliner made its first flight from Burbank on 10 October 1956. Amazingly, only three Starliners were used for a short 251-hour flight test program to get airworthiness approval on 19 March 1957. With a cost of $3 million per aircraft, TWA inaugurated L-1649 Starliner services on 1 June 1957, exactly one year to the day that the Douglas DC-7C was introduced into service. Though the DC-7C was faster, the Starliner had a longer range as well as a quiet and smooth ride thanks to increased sound insulation in the cabin and a flexible wing that dampened inflight turbulence. TWA marketed its Starliners as "Jetstream Starliners" and on marketing artwork, the wingspan of the Starliner was exaggerated to make the engines appear further from the fuselage than they were. In addition, artists cleverly depicted the Starliner without propellers, much to the ire of competing airlines that cried foul over the advertising campaign they called deceptive. TWA's famous inflight Ambassador Service was upgraded for the Starliners. The passenger seats were called "Siesta Sleeper Seats" that had pull out foot rests and a deep seatback recline that were nearly as comfortable as the sleeper berths which of course were still available on the Starliner's long routes. In the lounge area of each Starliner were cabin wall murals created specifically for TWA's aircraft by the artist Mario Zamparelli that showcased TWA's overseas destinations. 

The long range of the L-1649 Starliner allowed TWA to open up polar routes from the US West Coast to Europe. The inaugural TWA polar flight, Polar Flight 801, set a world record for the longest piston engine airliner flight on 2 October 1957 when flying westbound from London to San Francisco, encountered strong headwinds that resulted in a marathon 23-hour 19-minute nonstop flight. As impressive as the capabilities of the Starliner were, only TWA, Air France, and Lufthansa would be first-liner operators as few of the world's airlines had a route network and passenger traffic that made the Starliner economical. The Starliner only flew first line services for less than three years before getting displaced by the Boeing 707 and as a result of coming to market one year later than the Douglas DC-7C, only 44 Starliners were built compared to 121 DC-7Cs. When the final L-1649 Starliner was rolled out of the Burbank factory on 12 February 1958 for Lufthansa, it wasn't just the last Starliner but it was the end of the line for the Constellation family that stretched back to 1943. 

One interesting side note from TWA's operation of the Starliner came about due to reliability issues with the R-3350 Turbo Compound engines. While they were some of the most powerful piston engines ever flown, they were a maintenance nightmare compounded by the intricate plumbing work of the three power recovery turbines. In fact, TWA mechanics joked that PRT actually stood for "Parts Recovery Turbine". To minimize the disruption caused by engine failures, TWA acquired a military surplus Fairchild C-82 Packet transport that had a Westinghouse J34 engine in a dorsal nacelle as a jet booster. Nicknamed "Ontos" (the Greek word for "thing"), the C-82 could carry whole R-3350 Turbo Compound engines and a maintenance team to outlying stations where a Starliner might be stranded. Even though the Starliner would be phased out of TWA service, the airline kept Ontos in service to carry spare jet engines for the Boeing 707 and even the Boeing 747, finally retiring the odd bird in January 1972. 

Source: From Props to Jets: Commercial Aviation's Transition to the Jet Age 1952-1962 by Craig Kodera, Mike Machat, and Jon Proctor. Specialty Press, 2010, p77-85. 

The powerplant of the Reno Unlimited Class racer Rare Bear is quite different from that of the standard Grumman F8F Bearcat. The Rare Bear has had the standard Pratt & Whitney R-2800 engine replaced with a larger Wright R-3350 radial engine. Unlike the tempermental R-3350s that were used on the B-29 Superfortress, Rare Bear's engine utilized parts from R-3350s that were ruggedized for airline use- but since those engines were too heavy for air racing, only the parts that were absolutely necessary were used.

The supercharger was also customized using one from a Lockheed EC-121 Constellation as a basis. Since the Constellation's supercharger was designed for direct-head fuel injection, it wasn't compatible with the Rare Bear's engine, so it was modified to work with the Rare Bear's pressure carburetion system.

A stock R-3350 generates 2800 horsepower at 2600 rpm with 45 inches of manifold pressure. The modifications to the Rare Bear's engine gives it's R-3350 4000 horsepower at 3200 rpm and 80 inches of manifold pressure.

Source: Air & Space Smithsonian, November 2009. "The Bear is Back- Can an air racing legend win again at Reno?" by Preston Lerner, p45-46.