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 Douglas F6D Missileer

The F6D Missileer's resemblance to the F3D Skyknight is apparent

In 1957 the US Navy issued a specification for carrier-based fleet defense fighter that could loiter for long periods of time at long distances from the carrier. In addition, the aircraft had to be able to engage enemy aircraft at 100 nautical miles with a powerful onboard radar and long-range air-to-air missiles. Under the assumption that enemy aircraft were to be destroyed at well beyond visual range, dogfighting capability was not necessary and the need for long endurance dictated a subsonic design. Six hours was the specified endurance for this fighter and in turn this meant a large fuel load. The complex radar systems planned called for a three-man crew, with the pilot and co-pilot on each side of the radar intercept officer, this way both of the flying crew man could share some of the same displays with the radar intercept officer (RIO). 

There were four components to 1957 concept for fleet air defense that would be issued to industry for submissions. The first, of course, was for the aircraft itself, which was awarded to Douglas Aircraft Company in 1959 for what was designated the F6D Missileer. But in addition, a contract was awarded to Westinghouse for the AN/APQ-81 radar that would be used by the F6D to track and engage enemy aircraft. The third component was a contract awarded to the Bendix Corporation for the large AAM-N-10 Eagle missile. What is little-known about the F6D program was the fourth component, for an advanced airborne early warning aircraft to search out targets for patrolling Missileers. This contract would go to Grumman Aircraft which resulted in the W2F Hawkeye (later redesignated E-2 Hawkeye) with its advanced AN/APS-125 radar which could scan an area 400 miles in diameter and cue several F6D Missileers. 

Overall configuration of the F6D Missileer

The F6D itself resembled a scaled-up version of the Douglas F3D Skyknight twin-seat all-weather/night fighter. The nose section was quite bulbous to house the Westinghouse AN/APQ-81 radar and the three man crew were seated side-by-side in a cockpit that resembled that of the Grumman A-6 Intruder. Two non-afterburning Pratt & Whitney TF30 turbofans were mounted on each side of the fuselage just under the unswept wings. At the time, the use of a turbofan engine in a combat aircraft was a new concept and the TF30 was selected for its fuel economy. Since the Missileer didn't have to be supersonic, there was no need for a heavy and fuel-hungry afterburner. 

The Westinghouse AN/APQ-81 radar would have been the most advanced radar of its day using pulsed-Doppler technology years before the first production pulse-Doppler radars would enter service. The radar had a maximum range against large aircraft of 120 miles and could track as many as eight targets at once. The radar could also send mid-course corrections to the Eagle missiles. 

Overall configuration of the AAM-N-10 Eagle missile

The Bendix AAM-N-10 Eagle was the first of the four components from the 1957 fleet defense concept to be awarded. A large solid rocket booster would boost the Eagle to Mach 3.5 after launch on a loft trajectory for maximum range. After the booster was jettisoned, the Eagle's own sustainer motor ignited and further accelerated the missile to Mach 4.5. The use of a loft trajectory gave the Eagle missile a range of 160 miles and on final approach to the target, the missile's own onboard radar system (based on the radar used on the Bomarc surface-to-air missile) switched on. The Eagle could be armed with either a conventional or nuclear warhead.

Despite the advanced nature of the technology used in the F6D Missileer program, many quarters in the Navy fundamentally opposed the concept, arguing that once the Missileer had fired its six Eagle missiles, it was left vulnerable and unable to defend itself as it lacked any other armament and its large subsonic size precluded any evasive maneuvers. Once firing its missiles, the Missileer faced a long return flight to the carrier to refuel and re-arm. In 1960, the building opposition within the US Navy won out and the F6D Missileer program was canceled along with the Westinghouse AN/APQ-81 radar and what was becoming an enormously complex AAM-N-10 Eagle missile. The cost of developing the missile itself was estimated to be more than the aircraft development cost. 

However, the development of the Grumman W2F/E-2 Hawkeye continued and the aircraft is still in production today, albeit with more advanced radar systems, and is perhaps sole remaining legacy of the ambitious, but flawed, F6D Missileer program. 

Source: American X & Y Planes: Volume 2; Experimental Aircraft Since 1945 (Crowood Aviation Series) by Kev Darling. The Crowood Press, 2010, p60-61. Photos: Wikipedia, various internet forums.

Vought's Not-So-Fearsome F6U Pirate

In September 1944, the US Navy gave eight aircraft manufacturers a shot at a contract to build its first carrier-based jet fighter. The Navy relaxed its usual carrier and landing takeoff limitations as much as was practical in order to "obtain the highest possible performance for a carrier-based VF type." Of the eight companies approached, four of them submitted designs- Grumman, McDonnell, North American, and Vought. Douglas was already working on the Navy's D-558 Skystreak research aircraft program and therefore didn't bid. The Navy selected three of the companies to build their designs in order to spread out the risk amongst several approaches. Grumman, to everyone's surprise, didn't make the cut. Grumman's submission was felt to be too close and similar to Vought's submission and thus represented a duplication of effort (this same reasoning led to Boeing's Light Weight Fighter, LWF, submission to be disqualified in the 1970s as it was too similar to the General Dynamics submission which became the F-16). The Navy justified this as Grumman was much busier with the coming F7F Tigercat and F8F Bearcat programs while Vought only had the F4U Corsair program which would be winding down wit the end of the war. 

McDonnell's submission became the FD-1/FH-1 Phantom and would be the first carrier-borne jet fighter to go into service with the Navy. North American's submission became the FJ-1 Fury, and Vought's design, the one which we'll focus on in this post, became the F6U Pirate. The Pirate along with the Fury wouldn't have folding wings, instead those jets had an auxillary nose wheel which was inserted into a socket under the nose. The nose wheel was then retracted and the plane "kneeled" forward. This allowed the nose of another aircraft to be parked under the tail of another to compensate for the lack of folding wings. 

Built and designed at Vought's main facility in Stratford, Connecticut, it was powered by a single Westinghouse axial-flow J34 engine. Since the J34 was much slimmer than the J33 used on the Fury, the Pirate had a very slender fuselage by comparison to the other single engine design, the Fury. Because the J34 engine was felt to be still-experimental, only taxi runs were performed in Connecticut and the F6U prototype was disassembled and flown to Muroc Army Air Field (later it would be named Edwards AFB) in California for its first flight. It wasn't a good start- 24 minutes into the maiden flight on 2 October 1946, the accessory drive failed and the test pilot, Ted Owens, had to make an emergency landing on the lakebed. The flight test team had to wait 45 days before Westinghouse could provide another engine. Despite other technical issues cropping up in the flight test program, the Navy went ahead and issued an initial production contract for 30 F6U fighters along with contracts for the Phantom and Fury. And this was before the flight test program at Muroc uncovered even more programs with the Pirate- first came the discovery of very unpleasant stall characteristics. Then as the F6U approached Mach 0.6, the rudder began to demonstrate buffet issues. Once this was resolved and the flight envelope was expanded further, the poor longitudinal stability of the Pirate gave it unacceptable Dutch roll oscillations in flight. This resulted in several modifications to the tail unit and aft fuselage. But worst of all, the F6U was woefully underpowered- it had the same equipment (pilot, cockpit, guns, avionics, etc.) as the FH-1 Phantom's immediate successor, the F2H Banshee, but only 1/2 the engines. Whereas the Banshee used two J34 engines, the Pirate had only one. Vought's solution was to incorporate the first jet engine afterburner on a production aircraft, but this added weight and required further rework of the Pirate- something not made any easier with the flight tests taking place in California and the engineering located in Connecticut. To further worsen matters, the afterburner wasn't fully reliable, not always lighting when commanded.

With the Pirate program now approaching two years behind schedule, Vought decided to move the entire program to Grand Prairie, Texas, at NAS Dallas. Many of Vought's engineering and production staff refused to move to Texas and this further exacerbated the delays in the F6U Pirate program. To make matters worse, it was discovered that the main runway at NAS Dallas wasn't long enough for the F6U Pirate and it had to be extended further out into Mountain Creek Lake. While this was being done, the first production F6U Pirates were flight tested at Carswell AFB in Fort Worth starting in June 1949. This didn't sit well with the USAF and the biggest non-military tenant at Carswell, Convair. To avoid further conflicts, the flight testing then got moved again, this time to Ardmore, Oklahoma, at what would later become Ardmore AFB. By the time Vought managed to make the first flight of the first production F6U Pirate, it should have had all 30 of the first production order already delivered to the Navy. By this point, the successor to the FH-1 Phantom was already entering service, the McDonnell F2H Banshee and the first Grumman F9F Panthers were also entering service. By October 1949 only two production Pirates had been accepted by the Navy. By February 1950, Vought managed to deliver all thirty of the contracted F6Us- most of them were stored with VX-3 and then parceled out to various Navy testing facilities. No attempt was made to even carrier-qualify the Pirate- the thirty production aircraft only flew a sum total of 945 hours and most of the aircraft had less than 10 flight hours- enough for a production flight acceptance test flight and a ferry flight to its final disposition.

The go-ahead for production for the Pirate surprised many in the Navy. It was either a case of Navy sympathy for a long valued supplier and as a possible back up for the Grumman F9F Panther program. But whatever the case may be, the Vought F6U Pirate was too little, too late and a shock to many observers given Vought's long history of successful carrier aircraft up to that point. It was a learning experience for Vought that they applied to their next carrier fighter, the F7U Cutlass, which ended up being just as troubled. Caught on the ropes, Vought finally got the carrier-borne jet fighter right with its third try in the form of the F-8 Crusader.

Source: U.S. Naval Air Superiority- Developement of Shipborne Jet Fighters 1943-1962 by Tommy H. Thompson. Specialty Press, 2008, p35-49.