Republic XP-72

Republic XP-72

Republic XP-72

The XP-72 was a development of the P-47 Thunderbolt. It was powered by the Pratt & Whitney R-4360-13 Wasp Major, a 28 cylinder radial engine capable of producing 3,500 hp. This was the most powerful piston engine to enter production during the Second World War. The majority of visual changes to the aircraft were as a result of this new engine. Despite the increase in size of the engine, the XP-72 had a slimmer nose than the P-47. This was achieved partly by moving the supercharger intake from the nose to the wing and partly by using a fan to cool the engine, allowing the use of a tight fitting engine cowling.

Republic received an order to build two prototype XP-72s on 18 June 1943. The first prototype flew on 2 February 1944. A second prototype, using a contra rotating propeller soon followed. Tests revealed that the XP-72 had the expected improvement in performance, with a top speed of 504mph. Republic received an order for 100 P-72s, but it was cancelled before production could begin.

Design and development

The XP-72 development paralleled that of another Republic design, the XP-69 that was to be powered by an experimental 42-cylinder Wright R-2160 liquid-cooled inline radial engine mounted in the nose of the aircraft and driving contra-rotating propellers. [1] The XP-69 was intended for high altitude operations and featured a pressurized cockpit and armament of two 37 mm cannon and four 0.5 in machine guns. [1] As the XP-72 displayed greater promise than the XP-69, the XP-69 was cancelled on 11 May 1943 and an order for two XP-72 prototypes was placed on 18 June 1943. [1]

Republic P-72

XP-72 Serial: 36599 (43-6599) The second prototype equipped with Pratt & Whitney R-4360 engine with contra-rotating propellers. Basically a P-47 airframe wrapped around a massive radial engine, the XP-72 was designed as a fast and fast-climbing interceptor to match German flying bombs. Its unofficial top speed of nearly 500mph made it probably the fastest piston-engined aircraft ever.

The Republic XP-72 was based upon the P-47 airframe and was designed by Alexander Kartveli’s fighter team as a ‘Super Thunderbolt around the 3,000-hp (2237.1-kW) Pratt & Whitney R-4360-13 Wasp Major radial engine. The powerplant was, simply, the most powerful piston engine to reach production in any country during World War II. Intended primarily to be faster than the Thunderbolt, the XP-72 was viewed in part as a remedy for the Third Reich’s high-speed V-1 buzz bomb. The USAAF planned to use the fighter to intercept buzz bombs, taking advantage of its ability to reach 20,000 ft (6096 m) in just under five minutes. An armament of six 0.5-in 112.7-mm) guns would have been carried.

The first of two examples (43- 6598) flew a t Farmingdale on 2 February 1944 using a large four-bladed propeller. The name of the pilot is not recorded, but C. Hart Miller was active in Republic flight test at the time. The second XP-72 (43-6599) flew in July 1944 with the intended Aeroproducts six-bladed contra-rotating propeller. The second aircraft, however, was lost on an early flight. With priority shifted to long-range escort fighters, this promising interceptor was not needed. The other XP-72 airframe is thought to have been scrapped at Wright Field around VJ-Day.

Specifications (XP-72)

General characteristics

Wingspan: 40 ft 11 in (12.47 m)

Empty weight: 11,476 lb (5,216 kg)

Loaded weight: 14,433 lb (6,560 kg)

Max. takeoff weight: 17,490 lb (7,950 kg)

Powerplant: 1 × Pratt & Whitney R-4360-13 radial engine, 3,500 hp (dash 13 engine) (2,574 kW)


Maximum speed: 490 mph (789 km/h)[1][N 1]/ 387mph (623 km/h at sea level)

10 thoughts on &ldquo Republic XP-47J Superbolt Fighter &rdquo

Mr. Pearce, Thank you for this interesting article. You are quite correct the record-breaking 505 mph flight (classified at the time because of its military sensitivity) was made on August 4th, 1944. I have primary source material because my late father, Mike Ritchie, was the pilot.

For those who may be interested in the human dimension of the pre-jet aviation speed records, this was just another day at the airfield for my father, minus the photo op with the company president and the Air Force VIPs. He was a modest man doing what he enjoyed testing aircraft. He took aviation engineering classes at night while working full time, and met and married my mother, a draftswoman at Republic who also collected pilots’ flight cards.

The ‘Superbolt’ moniker was part of the early marketing of the P47J (faster, lighter, etc). But the nose art was subject to change. I have photographs suggesting that Superman was hastily repainted over a curvaceous blonde ‘Gravel Gertie’ image on the nose, before the plane’s moment in the sun. Early political correctness at work perhaps?

It is easy to forget the danger these brave pilots (at the time only men) risked daily in experimental planes. The tail of a new plane Mike flew in 1949, the XTB3F-1 “Guardian” broke apart, killing his flight engineer. He parachuted out at high speed and low elevation, but landed on top of the crash, breaking 3 bones and spending 2 months in the hospital. Fortunately my father recovered and went on to work on Grumman’s lunar module project among others. He also had four more children including me, seven in total.

I never learned of my father’s longstanding speed record until after it was broken (45 years later in 1989 by a souped-up, larger engine version of the Grumman Bearcat, another plane Mike flew). He casually dropped mention of it into dinner conversation, explaining the limitations of the piston engine/propeller driven aircraft. Apparently the wings of the “Jug” were awesome. My mother didn’t even look up , just kept eating her broccoli (she claimed she never worried about dad when he was at the office).

In 1994 on the 50th anniversary of the record setting flight, a dinner was held on Long Island to honor the contributions of the team of designers, engineers, mechanics, and pilots who guided the Thunderbolt program and its contributions to the Allied victory and aviation history. Dad was surprised to discover he was among the guests of honor. He greatly enjoyed seeing some old friends there. Unfortunately lymphoma and Parkinson’s disease combined to take his life three months later at age 80. A former naval aviator, he’d survived hundreds of flights in a total of 18 experimental and new planes (not counting minor model modifications). Mike was one of 7 Ritchie brothers who served in the US armed forces during World War II and the Korean War, all of whom returned safely. The Greatest Generation served with such valor and humility.

From biplanes, stellar navigation and unpressurized cockpits to lunar landing craft engines, his lifetime ran parallel to the golden age of aviation. Thank you for the opportunity to affirm details and contribute this remembrance of my personal aviation hero: M. Michael Ritchie 1914-1994. Rest in peace.

I thoroughly enjoyed reading your post. Accurate information on the XP-47J is hard to find, and first-hand accounts like yours are invaluable to the preservation of its history and the memory of those involved. Thank you very much for taking the time to write up such a fascinating message.

You are most welcome. It’s fun to help keep history alive for all those interested in it.

WOW, you are proud of your Dad and should be. We had a summer place at Babylon at the beach. I was thrilled by the test flights and “dog fights” with the Grumman guys. Talk about a good time.LOL.

Thank you both for filling in a large gap in my knowledge of aviation history. I have loved airplanes and flying all my life and continue to be amazed at the accomplishments of Golden Age and The Greatest Generation.
A friend of my family was a fellow named Dean C. Smith. He flew mail in the 1920’s with Charles Lindbergh, was a pilot on the first 2 Byrd expeditions and became the first pilot at American Airlines (Seniority #1). Thanks to him I became a professional pilot, with a career in airplanes and helicopters for almost 50 years.
May you always have clear skies and the wind at your back (except, of course, on landing).

Thank you for the kind words and I’m glad you liked the article.

Thank you, Beth for contributing your part of the history of “the Jug”. My father was an engineering test pilot at Nadzab, New Guinea during World War II. The P-47 was among the many aircraft types he flew in that position and in combat. He had a great fondness for “The Jug”, as did many other pilots, and was greatful for its rugged construction. Later in life he told me of his experience testing the P-47 in a terminal velocity dive and encountering compressibility while exploring recovery techniques.

An excellent article and I appreciate the comments from the other readers which are an education, too!

There is another report of high speed in the -47J. Wright Field test pilot Ralph Hoewing, in a reminiscence written c1991 or 1993, states he was sent to Farmingdale by the Air Force in August of 1943 to test the J, with the -61 engine. He “recall”s that with upgraded supercharger it had mil power available to 36,000 feet (67 inches?) The speed runs were at 36,000 or 37, 000 feet. It would take about 3-4 min to get a stabilized speed run after reaching test altitude. The engine got sick two minutes in, over Central Park. Next day, new engine — also “blows.” Two days later, third try. This time the engine did not fail until just before landing. TAS 506+ mph. At least some of this doesn’t make a lot of sense. But he apparently is referring to an illustrated -47 (which is suspect is a forerunner of the J or M) that looks like a normal D except that it has a funny belly scoop aft of the wing and apparently only 6 guns. It is called the J in the caption and the year is given as 󈧰. A second photo of a D with a different belly scoop is “P47DCH 26450” appears elsewhere in the book. I don’t know what to make of all this, but I think at least some of the Hoewing story is true, but not all. (Test Flying at Old Wright Field, 2nd edition)

Seen from my distant country, I’m an admirer. I believe it must be said loud and clear that what is part of the history of techniques, even the most warlike, does not have its own nationality but belongs to the history of humanity …

Airplanes in the skies + FAF history

The Republic XP-72 was an American prototype interceptor fighter developed as a progression of the P-47 Thunderbolt design. The XP-72 was designed around the Pratt & Whitney R-4360 Wasp Major 28-cylinder air-cooled radial engine with a supercharger mounted behind the pilot and driven by an extension shaft from the engine. The armament consisted of six 50 caliber wing-mounted machine guns and underwing racks for two 1,000 lb bombs.

The XP-72 development paralleled that of another Republic design, the XP-69 that was to be powered by an experimental 42-cylinder Wright R-2160 liquid-cooled inline radial engine mounted in the nose of the aircraft and driving contra-rotating propellers. The XP-69 was intended for high altitude operations and featured a pressurized cockpit and armament of two 37 mm cannon and four 50 caliber machine guns. As the XP-72 displayed greater promise than the XP-69, the XP-69 was cancelled on 11 May 1943 and an order for two XP-72 prototypes was placed on 18 June 1943.

The XP-72 flew for the first time on 2 February 1944, equipped with a four-bladed propeller. The second prototype was completed on 26 June 1944 and was equipped with an Aero-Products contra-rotating propeller. As the XP-72 displayed exceptional performance during flight tests, an order for 100 production aircraft was awarded. The order included an alternate armament configuration of four 37 mm cannon.
By this time, the war had progressed to where the need was for long-range escort fighters and not high-speed interceptors. Furthermore, the advent of the new turbojet-powered interceptors showed greater promise for the interceptor role.
Thus, the production order for the P-72 was cancelled.

General characteristics
Crew: One
Length: 11.15 m
Wingspan: 12.47 m
Height: 4.88 m
Wing area: 27.9 m²
Empty weight: 5,216 kg
Loaded weight: 6,560 kg
Max. takeoff weight: 7,950 kg
Powerplant: 1 × Pratt & Whitney R-4360-13 radial engine, 3,500 hp (dash 13 engine) (2,574 kW)
Maximum speed: 789 km/h - 623 km/h at sea level
Range: 1,932 km
Service ceiling: 12,805 m
Rate of climb: 26.8 m/s
Wing loading: 235 kg/m²
Power/mass: 0.39 kW/kg
Armament: 6× 50 caliber Browning machine guns
or two 37mm M4 cannons and 4x 50 caliber Browning machine guns
or 4 x 37mm M4 cannons
2× 476 kg bombs


The XP-72 development paralleled that of another Republic design, the XP-69 that was to be powered by an experimental 42-cylinder Wright R-2160 liquid-cooled inline radial engine mounted in the nose of the aircraft and driving contra-rotating propellers. Ώ] The XP-69 was intended for high altitude operations and featured a pressurized cockpit and armament of two 37 mm cannon and four 50 caliber machine guns. Ώ] As the XP-72 displayed greater promise than the XP-69, the XP-69 was cancelled on 11 May 1943 and an order for two XP-72 prototypes was placed on 18 June 1943. Ώ]

Republic XP-47H Thunderbolt

Authored By: Staff Writer | Last Edited: 10/27/2020 | Content © | The following text is exclusive to this site.

Like many of the American war-winning fighter aircraft of World War 2 (1939-1945), the Republic P-47 "Thunderbolt" was the subject of many experiments, modifications, and offshoots to help extract additional power and performance from the excellent airframe. The P-47D model became the definitive wartime production model and the promising, yet-developmentally troubled, P-47M was limited to just 130 examples before the company moved on the follow-up P-47N - which was given extended fuel stores to better cope with long ranges of the Pacific Theater. More radical conversions were still had between these more notable forms and the XP-47H was a late-war attempt to turn the "Jug" into an inline-engined fast fighter.

The XP-47H was born from two P-47D-15-RA production airframes ("Razorback" models) set aside specifically to test the new Chrysler XI-2220-11 16-cylinder inverted-Vee liquid-cooled inline engine promising up to 2,500 horsepower. These aircraft were pulled from Republic's production line in Evansville, Indiana, a facility set up to help offset the heavy industrial need for Thunderbolts in the American war effort. The H-model more or less retained the form and function of the P-47D but the new, and utterly complex, Chrysler engine installation meant that the rather basic fuselage of the P-47D would need to undergo considerable modification to accept the powerplant.

As a test bed, the fighter was stripped of all of its armament and "military" equipment. Unlike the "open-nosed" air-cooled radial piston engine fitted to the original D-models, the XP-47H was given an all-new forward section shaped around the liquid-cooled inline engine. The nose was very pointed thanks to the spinner which was streamlined with the general shape of the aircraft. The engine drove a four-bladed propeller unit and also caused the nose section to extend noticeably forward of the cockpit - limiting the pilot's forward vision. Under the nose was seated a cooling radiator air scoop designed to draw air as the aircraft reached speed and this gave the revised Thunderbolt a deeper side profile than normal and made a large aircraft appear even larger.

All other physical qualities of the D-model were retained including the elliptical wing mainplanes, single-finned tail unit, and tail-dragger undercarriage (retractable). The pilot sat at midships underneath a heavily-framed canopy which slid back on side rails. The raised fuselage spine of the Razorback Thunderbolts limited views to the critical rear of the aircraft - later remedied by the introduction of a bubble-style canopy design during the war.

The Chrysler inline proved more trouble than it was ultimately worth and delays incurred on that project naturally delayed the XP-47H program. As such, the H-model's prototype did not go airborne until July of 1945 and even then the intended axial flow supercharger tied to the engine was not in a ready state so a General Electric CH-5 turbosupercharger unit was substituted in its place.

With the program slowly progressing, engineers were optimistic for a maximum speed of around 490 miles per hour - making the H-model one of the fastest piston-engined fighters of the war. However, testing soon revealed that the XP-47H was a dead-end project - doomed by its troublesome engine, spotty development successes, and the end of the war in the Pacific come August 1945. During testing, the H-model recorded a maximum speed of 414 miles per hour, far short of the expected performance gains - and this without weaponry or military equipment fitted.

The project was eventually dropped by Republic despite the high investment already put into the fighter.

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The Republic XP-72 Wasp Major-powered “Super Thunderbolt” (or “Ultrabolt”) was being developed in the latter part of of WW2 as the ultimate incarnation of the P-47 Thunderbolt. Only two prototypes were built, one of which was given an Aero Products contra-rotating propeller arrangement and had an estimated speed of up to 550 mph.

A promising plane –yet it was finally cancelled. The XP-72 was no longer needed, prop-powered aircraft were reaching their technological apex and turbojet technology was beginning to take hold. Yet another of WW2’s “what ifs”, leaving to the imagination what impact such a powerful aircraft could have had in operational service.

AG1 lights
AG2 drop bombs
AG3 tail wheel steering lock/unlock
AG8 toggle exhaust smoke

Republic XP-72 - History

A Brief History of Aircraft Carburetors and Fuel Systems
Part 8: Bendix-Stromberg Pressure Carburetors

by Terry Welshans
Bardstown, Kentucky
for the Aircraft Engine Historical Society
Published Aug 2013 Revised 20 Mar 2018

The Bendix-Stromberg pressure carburetor is a more or less conventional carburetor design in most respects, in that all of the air and fuel control systems are present, but in a modified form. The fuel within the carburetor is always under pressure from its entry into the fuel regulator until sprayed into the airflow past the throttle or into the eye of the supercharger. Like the float-type carburetor, this carburetor is available in downdraft and updraft designs. There is a small horizontal model available for engines requiring this design, which mount vertically in small helicopters.

Fig. 80. Bendix-Stromberg PT-13G1 Pressure Injection Carburetor (Top View) Used on Pratt & Whitney R-2800 Engines

  • The pressurized fuel circuit prevents entrapped air within the fuel circuits.
  • An air portion regulator that responds to ram air pressure and boost venturi vacuum, together representing the mass of air flowing through the carburetor, determines the fuel flow.

Connected to this airflow sensor diaphragm is a fuel pressure regulator diaphragm that holds a constant fuel pressure in the fuel discharge piping, the flow rate being determined by the position of the air sensor diaphragm.

The throttle is located in the air stream after the air has passed through the venturi. It was possible to discharge the fuel at any location beyond the throttle, thus greatly diminishing the throttle icing. The carburetor has one or more fixed venturis, thereby avoiding compressibility difficulties experienced in the Chandler-Groves carburetor when the variable-venturi throttle was in cruise power at high altitude.

Wright Aeronautical received a prototype of the new Stromberg floatless carburetor setup for the Cyclone 9 engine, and engineers immediately began to work as intensively on its development as they had on Chandler-Groves carburetor development. Sometime later a prototype for a Pratt & Whitney Twin-Wasp engine was ready. Pratt & Whitney had disliked the Chandler-Groves design and had provided only minimal assistance with its development. P & W approved the new Stromberg design, and like Wright, did a great deal of work toward its development. The new Stromberg floatless carburetor was in production in 1938, and was an immediate success. Like the Chandler-Groves carburetor, it was free from float problems, and was much less prone to icing than the float-type carburetor. The Stromberg automatic mixture control was sound in principle, and although it was not working perfectly in 1938, by 1940 it was completely satisfactory.

Pratt & Whitney adopted the Stromberg floatless carburetor for all of its high-power engines. It also was used by the Army on all the Wright G-200 Cyclones that powered Boeing's B-17. Pratt & Whitney later developed a system where fuel sprayed into the supercharger inlet instead of immediately after the carburetor, and with that change, fuel refrigeration icing problem no longer existed.

Fig. 81. Bendix-Stromberg Fuel Delivery Nozzle

The new Bendix floatless carburetor design replaced the float-operated fuel inlet valve with a servo-operated poppet-style fuel-metering valve. There are either one or two small vent floats in the fuel regulator air bleed system. These floats have nothing to do with the air-fuel ratio, as their only purpose is to allow any air trapped in the fuel regulator to return to the fuel tank where it vents to the atmosphere.

  • Throttle body &mdash Containing the venturis and throttles. All other components bolt to this portion.
  • Fuel control &mdash Contains the jets and mixture control plates. When equipped with an ADI water injection system, this portion also has the derichment diaphragm and valve.
  • Fuel regulator &mdash The brains of the carburetor. It contains the fuel and air diaphragms, main metering valve and enrichment diaphragm and valve.

The throttle body is the main portion of the carburetor. It contains one or more bores through which all of the air flows into the engine. Each bore contains one or two throttle plates to control airflow into the engine. Downdraft carburetors are used on R-1300, V-1710, R-1820, R-1830, R-2000, R-2600, R-2800, R-3350 and R-4360 engines. Other Bendix Stromberg carburetors are updraft designs used on V-1650 engines.

All remaining main portions attach to the throttle body, where they interconnect with internal passages or external tubes or hoses. The boost bar portion measures air density, barometric pressure, and the amount of air flowing through the carburetor. Bendix-Stromberg carburetors use a double or boost type venturi developed and patented for automobile carburetors. Obtaining the vacuum used by the fuel flow control valve from a smaller boost venturi resulted in a reduction of air pressure losses. This portion mounts in the airflow at the carburetor inlet. The automatic mixture control, if used, is mounted either on the boost portion for a throttle body with two or more throats, or on the throttle body itself for single throat models. The throttle body may have an adaptor bolted to the carburetor base that changes airflow direction. This adaptor may have the fuel discharge nozzle and accelerator pump attached to it. Small aircraft engines can be equipped with a single throat pressure carburetor. This carburetor throttle body contains all of the other components listed above.

Fig. 82. Bendix Stromberg PD12 Downdraft Throttle Body Fig. 83. Bendix-Stromberg PD-12 Injection Carburetor Boost Venturi and Automatic Mixture Control
Fig. 84. Bendix-Stromberg PD-12 Injection Carburetor Discharge Nozzle and Accelerator Pump Fig. 85. Bendix Stromberg PS-6BD Injection Carburetor Schematic

The pilot operates the fuel control to adjust fuel flow into the engine. The fuel control contains a number of jets that control internal fuel pressures. The idle valve and its operating lever and adjustable linkage are visible at the lower part of Figure 86.

    The fuel control has a rotating plate-type mixture control valve with three positions:
  • Idle-Cutoff, which stops all fuel flow
  • Auto Lean, which is used for normal flight or cruise conditions
  • Auto Rich, which is used for takeoff, climb and landing operations

Fig. 86. Bendix-Stromberg Carburetor Fuel Control Fig. 87. Bendix Stromberg Injection Carburetor Fuel Control Fig. 88. Bendix-Stromberg Carburetor Fuel Regulator

This is the "brain" of the carburetor. Movement of a diaphragm that measures engine mass airflow adjusts the position of the fuel-metering valve accordingly, and controls the fuel flow rate. The poppet-type metering valve is located under the round cover retained by six studs and nuts (Fig. 88).

Fig. 89. Bendix-Stromberg Pressure Carburetor Schematic

Four main chambers comprise the Bendix-Stromberg fuel regulator. The air diaphragm separates the "A" and "B" chambers, which are closest to the throttle body. Chamber "A" contains the pressure from the impact tubes. Chamber "B" contains the suction from the boost venturi. The difference in pressure between the two air chambers creates the air metering force. The fuel-metering diaphragm separates the "C" and "D" chambers, which are located outboard on the same valve stem as the air-metering diaphragm. Chamber "C" contains "metered fuel" (fuel that has already passed through the jets, but not yet injected into the air stream) chamber "D" contains "unmetered fuel" (the fuel as it enters the carburetor). A fuel pressure drop results as the fuel flows through the jets and into chamber "C". The reduced pressure in chamber "C", on one side of the fuel diaphragm, and unmetered fuel at fuel pump pressure in chamber "D", on the other side of the diaphragm, create the fuel metering force.

The fuel-metering valve is located at the outboard end of the valve stem, and responds to the total pressure differential across the air and fuel diaphragms. The resulting valve stem movement controls fuel flow into the engine under all flight conditions by slightly opening or closing the fuel-metering valve as necessary.

Fig. 90. Bendix Stromberg Downdraft Pressure Carburetor

The regulator is a diaphragm-controlled unit divided into four primary chambers. Two regulating diaphragms separate the primary chambers from one another. Secondary balancing diaphragms compensate for differences in diaphragm areas caused by the valve stem and the poppet valve assembly. Chamber "A"contains regulated air scoop pressure chamber "B" contains boost venturi pressure chamber "C" contains regulated fuel pressure chamber "D" contains unregulated fuel pressure. Refer to Figure 90 , and assume that for a given airflow (measured in in pounds per hour through the throttle body and venturi), a negative pressure of 0.25 psi is established in chamber "B". This tends to move the diaphragm assembly and the poppet valve in a direction to open the poppet valve, permitting more fuel to enter chamber "D", while the pressure in chamber "C" is held constant at 5 psi (10 psi on some installations) by the spring-loaded discharge nozzle or impeller fuel feed valve. Hence, the diaphragm assembly and poppet valve will move in the open direction until the pressure in chamber "D" is 5.25 psi. Under these pressures, there is a balanced condition of the diaphragm assembly with a pressure drop of 0.25 psi across the jets in the fuel control unit. In the event the nozzle pressure (chamber "C" pressure) rises to 5.5 psi, the diaphragm assembly balance will be upset and the diaphragm assembly will move to open the poppet valve so as to establish the necessary 0.25-psi pressure in chamber "D" and, thus, re-establish the 0.25-psi differential between chamber "C" and chamber "D". Hence, the drop across the metering jets will remain the same.

If the fuel inlet pressure is increased or decreased, the fuel flow into chamber "D" will tend to increase or decrease with the pressure change, causing the chamber "D" pressure to do likewise. This cycle will again upset the balanced condition previously established, and the poppet valve and diaphragm assembly will respond by moving to increase or decrease the flow to re-establish the same pressure differential established between chambers "C" and "D" as the 0.25-psi differential established between chambers "A" and "B".

Fuel flow changes when the mixture control plates move from the auto-lean to auto-rich or vice versa, thereby selecting a different set of jets or cutting one or two in or out of the system. A mixture position change causes the diaphragm and poppet valve assembly to reposition, maintaining the established pressure differential of 0.25 psi between chamber "C" and "D", maintaining the established differential across the jets.

Under low-power settings (low airflow), the difference in pressure created by the boost venturi is not sufficient to accomplish consistent regulation of the fuel. Hence, an idle spring is located in chamber D (Fig. 90). The poppet valve moves toward the closed position until it contacts the idle spring. The spring holds the poppet valve off its seat far enough to provide more fuel than is needed for idling. This potentially over-rich mixture is regulated by the idle valve. At idling speed, the idle valve restricts the flow to the proper amount, but at higher speeds, it is withdrawn from the fuel passage and has no metering effect.

The fuel delivery nozzle is either remotely mounted at the "eye" of the engine's supercharger or in the carburetor adapter after the carburetor body. The fuel sprays into the air stream as it enters the engine through one or more spring-controlled spray valves. The spray valves open or close as the fuel flow changes, holding a constant fuel delivery pressure.

An accelerator pump injects a measured amount of extra fuel into the air stream to allow smooth engine acceleration, and is either remotely mounted or mounts on the carburetor body. The accelerator pump is either mechanically connected to the throttle, or it is operated by sensing the manifold pressure change when the throttle is opened.

Some carburetors may have an optional anti-detonation injection (ADI) system. This carburetor modification consists of a "derichment valve" located in the fuel control, a storage tank for the ADI fluid, a pump, a regulator that provides a specific amount of ADI fluid based on the fuel flow, and a spray nozzle that is mounted in the air stream entering the supercharger.

Bendix-Stromberg produced a number of floatless carburetor styles and sizes, each calibrated to a specific engine and airframe. Each carburetor model number includes the style, size and a specific model letter,sometimes followed by a revision number. Each application (the specific engine and airframe combination) then receives a "list number" that contains a list of the specific parts and flow sheet for that application. There are hundreds of parts list and flow sheets in the master catalog. Bendix used a special method to identify round carburetor bores as found in the PS, PD and PT models. The first inch of bore diameter is the base number one, and each 0.25" increase in diameter adds one to the base number.

  1. A 1.25" bore would be coded as a size number 2 (the base number 1 plus 1 for the additional 0.25" over one inch)
  2. A 1.50" bore would be coded as a size number 3 (the base number 1 plus 2 for the two 0.25" increments over one inch), and so on up to a size 18 (the base number 1 plus 17 for the seventeen 0.25" increments over the one inch base).

The actual finished bore size is 3/16 inch larger than the coded size.

  • The first inch is the base number one, and we subtract that one from the size number 18. This leaves 17 one-quarter inch units, or 17/4, which reduces to 4.25".
  • Adding back the base number, we now have a 5.25" bore. Last, we add the 3/16 for a grand total of 5.4375" diameter.
  • To find the venturi area of this carburetor, use the formula for the area of a circle: A = &pi r².
  • Start with the diameter of 5.4375. Divide by 2 to get the radius, 2.71875". Square the radius to get 7.3916. Multiply by the value of &pi to get 23.22 in² area for one venturi bore. There are two bores in the PD-18 carburetor body, resulting in 46.443, or about 46.5 in².
  • PS models have a single round throat, and can be mounted updraft, downdraft and horizontal with slight changes in the vent connection. Models include PS-5, PS-7 and PS-9.
  • PD models have a double round throat, and can be mounted updraft and downdraft with slight changes. Models include PD-7, PD-9, PD-12, PD-14, PD-16, PD-17 and PD-18.
  • PT models have three round throats, can be mounted updraft and downdraft with slight changes. Models include PT-13.
  • PR models have two or four rectangular throats, can be mounted updraft and downdraft with slight changes. Models include PR-38, PR-48, PR-52, PR-53, PR-58, PR-62, PR-64, PR-74, PR-78, PR-88 and PR-100. The PR-64 two-throat pressure carburetor fits the Vought F4U-4's R-2800-32W engine and the Grumman F8F-2's R-2800-32W engine. The largest Bendix Stromberg pressure carburetor was the four-throat PR-100 used on the all versions of the R-4360 engine. This monster carburetor could provide airflow and enough fuel to feed ten 426

Fig. 91. Bendix-Stromberg PS-5C Pressure Injection Carburetor Found on Most Horizontally-Opposed Air-Cooled Aircraft Engines Fig. 92. Bendix-Stromberg PD-9G1 Pressure Carburetor for Pratt & Whitney R-1340 and Wright R-1300 Engines Fig. 93. Bendix-Stromberg PD-12K1 Pressure Injection Carburetor Used on Continental IV-1430, and Wright R-2600-3 and R-2600-23 Engines
Fig. 94. Bendix-Stromberg PD-18B1 Updraft Pressure Injection Carburetor used on Rolls-Royce Merlin 68, 69, and the Packard-built V-1650-7 Fig. 95. Bendix-Stromberg PT-13G1 Pressure Injection Carburetor Used with Pratt & Whitney R-2800 Engines Fig. 96. Bendix-Stromberg PR-58E5 Pressure Injection Carburetor Used on R-2800-C, -CA3, CA15, -CA15A, -CA18, -CA18A, -CB3, -CB6, -CB16, -CB16, -CB17, -18W, -42, -42W, -44W, -48, -50, -50A, -52, -52W, -54, -95, -97, -99W, and -103W

  • PS style carburetors fit on small opposed-piston engines of less than 700 in³. These engines power light aircraft and helicopters, and mount in the nose, tail, wing, or external to the airframe. These engines may also be mounted either vertically or horizontally.
  • PD style carburetors are for smaller inline and radial engines that have displacements from 900 to 1,900 in³.
  • PT style carburetors are for medium size inline or radial engines with displacements from 1,700 to 2,800 in³.
  • PR style carburetors are for large radial engines with displacements from 2,000 to 4,360 in³.

Specific Bendix Stromberg Injection Carburetor Applications
PS-5BContinental E-165, E-185
PM-8A1Ranger V-770-D1
PM-8A2Ranger V-770-D4
PM-8A3Ranger V-770-D1
QM-8A1Ranger V-770-D4
QM-8A2Ranger V-770-D1
PD-9C1R-1535-94, -96
PD-9C2R-1535-94, -96
PD-9D1R-1535-2, -92, -96Chance Vought SBU-3, SB2U-1, -2, -3
R-1340-36Curtiss SOC-4, North American SNJ-2, -3
R-1300-1A, -1B, -2A, -4A North American T-28A, PG-1, -2, -2W
R-1300-957C7RA1, -C7BA, -2, -2A, -2B
PD-9G1R-1300-3Sikorski HRS-3, HO4S-3, H-19B, D, UH-19
R-1300-3, -3A, -3B Sikorski HRS-3, HO4S-3, H-19B, D, UH-19
R-1300-3, -3C, -3D Sikorski HRS-3, HO4S-3, H-19B
R-1300-990C7BA1, R-1820-76A, -76BSikorski S-55
QD-9A1Ranger V-770-C1
QD-9A2Ranger V-770-6, -8, -11Curtiss SO3C-3
P & W R-1340-AN-1
QD-9A3Continental R-975-9A, -34
QD-9A4Continental R-97S-34
Continental R-975-34, -42, -46 Piasecki HUP-1, -2, -3, H-25A
QD-9B1Ranger V-770-C1B-11
QD-9ClContinental R-975-9A
QD-9D1Continental R-975-34, -42, -46, -46A
QS-9A1Menasco D6F-G
AS-12A1R-1340 Piasecki HUP-2, -3, H-25A
PD-12B4V-1710-21 (C10)Curtiss YP-37, P-37
V-1710-23 (D2) Bell YFM-1, FM-1, -1A
R-2180-5, -7Stearman XA-21
V-1710-21 (C10)Curtiss YP-37, P-37
V-1710-23 (D2) Bell YFM-1, FM-1, -1A
R-1830-21Douglas C-41
R-1830-S1CG, -SCGDouglas DC-3, C-41
PD-12B7R-1820-G10, -G102
R-1820-G102A, -79, -81, -83Douglas C-50B, C, D, C-51, Lockheed Hudson I, II
R-1820-G200, -G202A, -G205B, -71, -91Douglas C-49A, B, C, D
PD-12B8R-1830-SC3GDouglas DC-3
R-1830-S1C3GDouglas C-48B, C
R-1830-SC3G, -45Douglas DC-3, Curtiss P-36
R-1830-SC3GDouglas DC-3, Republic P-43
R-1830-49Lockheed A-28, Republic RP-43A, B, C
PD-12B8ER-1830-S1C3GDouglas C-48B, C
PD-12E1R-1830-76Grumman XF4F-3, -4, F4F-3
R-1830-76, -78, -88Consolidated PB2Y-2, -3, Grumman XF4F-3, -4, F4F-3
PD-12E2R-1830-76, -86Grumman F4F-3, -4, -7, Eastern FM-1
PD-12E3R-1830-76, -78, -88Consolidated PB2Y-2, -3, Grumman XF4F-3, -4, F4F-3
PD-12E4R-1830-76, -86Grumman F4F-3, Eastern FM-1
PD-12F2R-1830-C4, -C5
R-1830-43Consolidated B-24D, E, H, B-25C
R-1830-S3C4GDouglas DC-3C
R-1830-33, -41, -43, -57 Consolidated XB-24, RB-24, B-24A, B, C, D, E, PB3Y-3, Martin RB-10B, Lockheed A-28A
R-1830-S4C4GDouglas DC-3C, Lockheed 18-14
R-1830-67Douglas C-47, C-48, C-52, Lockheed PBO-1, RA-28A, C-57
R-1830-S3C4GDouglas DC-3C
R-1830-90Grumman F4F-3A, -4A, -6, G-36B
R-1830-43,-47Consolidated B-24, Republic P-34D
R-1830-S1C3G, -S3C4G Douglas DC-3C, C-48, C-52, Lockheed C-57
R-1830-41, -43, -55Consolidated B-24
R-1830-90BDouglas C-47B, Bristol Beaufort II
PD-12F3R-2000-D, -DG-1, -3
R-2000-1, -3, -7Douglas C-54A, B, C, F
PD-12F5 R-1830-90B, -90C, -90D Douglas DC-3, C-47B, D, C-117B, R4D-6, -7
R-1830-41, -43, -45, -55 Consolidated RB-24C, B-24B, C, D, E, PB4Y-1
R-1830-67Douglas C-47, C-48, C-52, Lockheed PBO-1, RA-28A, C-57
Jacobs XR-1530
R-1830-90B, -90C, -90D Douglas C-47B, C-47D C-117B R4D-6, -7 DC-3D
R-1830-43Douglas DC-3C
PD-12F6R-2000-1, -3, -7Douglas C-54A,B,C,F, DC-4
PD-12F7 R-2000-3, -7 Douglas C-54A, R5D-1, DC-4
R-1830-94 Consolidated P4Y-2, Douglas DC-3
R-1830-94, R-2000-3, -7, -11, -7M2, -DS5 Douglas DC-4, C-54, de Havilland DHC-4, CV-2B
R-2000-5, R-1830-75, R-2000-11
PD-12F8R-1830-75Douglas DC-3, Ford XB-24N, B-24N, XB-24K
R-1830-98Consolidated P4Y-2
R-2000-D1G, -D13G, R-2000-9,-13
R-2000-9, -13, -2SD1G, -2SD13GDouglas C-54, R5D
PD-12F13R-2000-4, -9, -13Douglas R5D-2, -3, -4R, -5, -5R
R-2000-4, -9, -11, -7M2, -13Douglas C-54, C-47, de Havilland DHC-4, C-7A, CV-2B
R-2000-2SD1G, -2SD13GDouglas DC-4
R-1830-75Douglas DC-3, Lockheed C-57
PD-12G1V-1710-27 (F2R), -29 (F2L), -49 (F5R), -53 (F5L), V-1710 -35 (E4), -37 (E5)Lockheed YP-38, P-38D, E, F, F-1, F-5, F-10
PD-12H1R-1830 (S1C3-G)
R-1830-66Consolidated PBY-3
R-1830-72Consolidated XPB2Y-1, XPBY-5A, PBY-4
R-1830-82Consolidated PBY-5,-5A, Douglas R4D-1
R-1830-84ALockheed R5O-3,
R-1830-92 Boeing PB2B-1,-2, Budd RB-1, Curtiss YC-76A, Lockheed C-54D, Consolidated PB2Y-3, -3R, -5, -5R, -5H, -5Z, PBY-5, -5A, -5B, Consolidated PBY-6, -6A, OA-10, NAS PBN-1, Sikorski JR2S-1, Douglas C-47A, C, R4D-1, -3, -4, -5, C-48A, C-53A, B, C, D, C-68, DC-3C, Vickers PBV-1A, OA-10A
R-1830-66, -82Consolidated PBY-3, -5, -5A, Douglas R4D-1
R-1830-S1C3G-53Douglas DC-3C, C-48B, C
R-1830-82,-88Consolidated PBY, Douglas C-48, C-52, Brewster OA-10
R-1830-57Republic P-43A, AT-12, Seversky P-35A
R-1820-50, -65, -73, -87, -91, -97, -G200Boeing B-17C, D, E, F, G
PD-12H3R-1820-G249, -G205B, -G202A
R-1820-G205A, -G202A, -71, -87 Douglas C-49A, B, C, D, Boeing B-17C, D, E, F, Lockheed PBO-1
R-1820-40, -42Brewster F2A-2, -3, Lockheed R5O-4, -5
R-1820-67, -69
R-1820-G200, -G202A, -G205A, -40, -42, -87, -93Boeing B-17C, D, E, F, Lockheed PBO-1, Hudson III
R-1820-G205A, -G105ADouglas DC-3
R-1820-G205Northrop N3PB
R-1820-G205A, -G202A, -54, -87Douglas DC-3, R4D-2, C-49, Lockheed PBO-1, R5O-6, Grumman F2F-6
R-1820-G205A, -87Douglas DC-3, C-49A, B, C, D
PD-12H4R-1830-66, C3Consolidated PBY-3
R-1830-72Consolidated XPB2Y-1, XPBY-5A, PBY-4
R-1830-82Consolidated PBY-5, -5A, Douglas R4D-1
R-1830-92Boeing PB2B-1, -2, Budd RB-1, Curtiss YC-76A, Lockheed C-54D, Consolidated PB2Y-3, -3R, -5, -5R, -5H, -5Z, PBY-5, -5A, -5B, Consolidated PBY-6, -6A, OA-10, NAS PBN-1, Sikorski JR2S-1, Douglas C-47A, C, R4D-1, -3, -4, -5, C-48A, C-53A, B, C, D, C-68, DC-3C, Vickers PBV-1A, OA10A
R-1830-90,-S1C3GDouglas DC-3
R-1830-S1C3GDouglas DC-3C, C-48B, C, C-52A, B, C, D, Lockheed C-57A, B
R-1830-66Consolidated PBY3
R-1830-92AConsolidated PBY-5A
R-1830-S1C3G-53Douglas DC-3
PD-12H5R-1820-50, -65Boeing B-17C, D, E, F
PD-12H7R-1830-C3, -66, -72
PD-12J1R-2600-3Douglas B-23, C-67
R-2600-A, -3, -11Douglas A-20B, C, P-70
R-2600-11Douglas BD-2, A-20A, B, C, B-23, C-67, P-70
PD-12J3R-2600-11Douglas A-20C
PD-12K1R-2600-3Douglas B-23, C-67
R-2600-23Douglas A-20C, G
Continental IV-1430
PD-12K2V-1710-35 (E4)Curtiss P-40, Bell P-39C, D, D-1, E, F, J, K, L
V-1710-37 (E5)Bell YP-39, P-39
V-1710-39 (F3R)Curtiss P-40D, E, E-1, M, N, North American P-51A, Republic XP-47
V-1710-51 (F10R)Lockheed P-38E, H, P-49 Bell P-39
V-1710-63 (E6)Bell P-39D-2-BE, K, K-1-Bell-1-BE, M
V-1710-73 (F4R)Curtiss P-40E, K, North American P-51A
V-1710-27 (F2R), -29 (F2L), -81, -99 (F26R), -115, -81, -99 (F26R)
PD-12K3V-1710-51 (F10R)Bell P-39, Lockheed P-38E, G1, G2, H, P-49
V-1710-55 (F10L)Lockheed P-38E, G1, G2, H
V-1710-89 (F17R), - 91 (F17L) Lockheed P-38E, H
PD-12K4R-1820-56, -60Eastern FM-2, Douglas SBD-5, -6
PD-12K6V-1710-39 (F3R)Bell P-39D, N
V-1710-63 (E6)Bell P-39D-2-BE, K, K-1-BE, L, L-1-BE, H, P-76
V-1710-67 (E8)Bell P-39M, P-76
V-1710-81 (F20R)Curtiss P-40M, N, North American P-51A
V-1710-83 (E18)Bell P-39M-1-BE
V-1710-85 (E19)Bell P-39N-l-BE, P-39Q-1-BE
V-1710-99 (F26R)Curtiss P-40N
V-1710-55 (F10L)Lockheed P-38E, H
PD-12K7V-1710-55 (F10L), -89 (F17R), -91 (F17L)
V-1710-Bell P-39
V-1710-51 (F10R)Lockheed P-38E, H, G1, G2, P-49
V-1710-55 (F10L)Lockheed P-38E, H, G1, G2
V-1710-87 (F21R)North American A-36A-l
V-1710-89 (F17R), -91 (F17L)Lockheed P-38N
V-1710-111 (F30R), -113 (F30L) Lockheed P-38L, M
V-1710-73, -89(F17R)
PD-12K8V-1710-109 (E22), -111 (F30R), -113 (F30L)
V-1710-115 (F31R)Bell P-63
V-1710-109 (E22), -111 (F30R), -113 (F30L)Lockheed P-38K, L, M
PD-12K9 V-1710-129 (E23)
PD-12K10R-1820-C9HD, -93
R-1820-56Lockheed C-56, Pac-Aero Learstar, CASA-202B
R-1820-G205A, 736C9GC
PD-12K11 Sterling Experimental (Marine)
PD-12K12V-1710-109(E22) , -111(F30R)
PD-12K14R-1820-76A, -76B, -86A, -101Grumman SA-16A, UF-1, North American T-28D, HU-16B
R-1820-992C9HD1, 987C9HD1Pac-Aero Learstar
R-1820-982C9HE1, 982C9HE2Hurel Dubois HD-34, HE-321
R-1820-82WAGrumman S2F-1
R-1820-56,-74Grumman UF-1
PD-12K15V-1710-109 (E22)
V-1710-133 (E30)Bell P-63F
PD-12K16V-1710-39 (F3R), -61, -81 (F20R)
PD-12K17V-1710-111 (F30R), -113 (F30L)
PD-12K18R-1820-737C9HD1, -78, -736C9HD3, -982C9HE1, -56, -74
R-1820-80, -82, -86North American T-28B, Grumman S2F-1
R-1820-76, -76A, -76B, -101Grumman SA-16, UF-1, UF-2
R-1820-88Goodyear ZPG-3W
R-1820-977C9HD3Vertol 44B
R-1820-80, -82, -86, -88North American T-28B, Grumman S2F-1
R-1820-80, -82, -82A, -86, -88North American T-28B, S-2D, E, F
PD-12K19R-1820-103Vertol H-21, CH-21
R-1820-977C9HD1, 977C9HD2Vertol 44B
R-1820-103Vertol H-21
PD-12K20R-1820-977C9HD1, 977C9HD2Vertol 44B
PD-12P1Continental IV-1430-3
PD-12P2Continental IV-1430-25Lockheed XP-49, McDonnell XP-67
PD-12P3Continental IV-1430
PD-12Q1 V-1710-(E32)
PD-12R1R-1820-84, -84A, -84B, 989C9HE1, -HE2Sikorski HSS-1, H-34, S-58
R-1820-84A, -84B, -84C, -84D, -9DSikorski HSS-1
R-1820-84A, -84B, -90 Sikorski H-34
R-1820-989C9HE1, -HE2Sikorski S-58, UH-34
PT-13B2V-1710-19Curtiss XP-40
PT-13D4R-2800-8Chance Vought F4U-1, -2, Brewster F3A-1, Goodyear FG-1
PT-13D5R-2800-8Chance Vought F4U-1
PT-13D6R-2800-8Chance Vought F4U-1
R-2800-8WChance Vought F4U-1
PT-13E1V-1710-33 (C15)Curtiss P-40B, C, G
V-1710-41 (D2A)Bell FM-1B
V-1710-33 (C15)Curtiss P-40B,C,G
PT-13E2R-2600-B, -7, -9Douglas A-20, P-70, C-47, North American B-25A, B,
Bristol Hercules
R-2600-7, -9Douglas A-20, P-70, C-47, North American B-25A, B
R-2600-10, -16Grumman TBF-1
R-2600-9Curtiss C-46
Wright 585C14BA1, 586C14BA1 (R-2600)
PT-13E5V-1710-47 (E9)Bell XP-39E, P-63A, P-76
V-1710-93 (E11)
PT-13E9 V-1710-47 (E9), -93 (E11), -117 (E21), -93 P-63A, B, E
PT-13E10V-1710-93 (E11), -117 (E21)
PT-13F1R-2800-5, -39Douglas B-23, Martin B-26A, B, C, Curtiss C-46, Lockheed B-34
R-2800-7Republic P-44
R-2800-6Chance Vought XTBU-1
R-2800-11North American B-28
R-2800-S1A4G, -5, -39 Vickers Warwick I, Douglas B-23, Martin B-26A, B, C
R-2800-21, -27Douglas A-26, Grumman F6F-4, P-47C, D, G
R-2800-25Northrop XP-61
R-2800-S1A4GVickers Warwick I
PT-13F5R-2800-27, -31, -51Lockheed PV-1, -2, RB-34
PT-13G1R-2800-A Curtiss C-46
R-2800-16Grumman XF6F-2, Chance Vought F4U-3
R-2800-21Curtiss P-47G, Republic P-47C, D, RP-47B, C, XP-47E, F, K
R-2800-27Douglas A-26B, C, B-23, JD-1, Grumman XF6F-1, XF6F-4, F7F-1N
R-2800-31Lockheed PV-1, -2A, B, C, D, -3, RB-34A, B
R-2800-41Martin B-26B-2
R-2800-43Curtiss C-46, Martin AT-23A, B, B-26B, C, D, E, F, G, TB-26H
R-2800-47Vickers Warwick II
R-2800-49Hughes XA-37
R-2800-51Curtiss R5C-1, -2, C-46A, D, E, F, G
R-2800-71Douglas A-26B, C, JD-1
R-2800-75Curtiss C-46A, D, E, F, G, XC-113
R-2800-79Douglas A-26-B, C, JD-1
R-2800-27, -31 Douglas A-26A, B, C, Grumman F7F-1, Lockheed PV-1, -2, -3, RB-34A, B
R-2800-35Republic XP-47B
R-2800-14, -16, -41 Chance Vought F4U-3, Grumman XF6F-2, Martin B-26B-2
R-2800-21, -27, -31, -63 Republic P-47B, C, D, G
R-2800-21Republic P-47C, D, RP-47B, C, XP-47E, F, K
PT-13G2R-2800-10, -29Grumman F6F-3, -5, Northrop XP-56, XP-61, P-61, Curtiss P-60
PT-13G5R-2800-21, -59, -63Republic P-47B,C, D, E, F, K, XP-47L
R-2800-27, -71, -75, -79 Douglas A-26 Curtiss C-46
PT-13G6R-2800-10W, -65Curtiss P-60, Grumman F6F-1, -3, Northrop P-61
PT-13H1 V-1710 (G1)
PT-13H2V-1710-135Bell P-63
PD-16A1V-1650-1Curtiss P-40F, L
PD-16B1V-1650-1Curtiss P-40F, L
Merlin 28, V-1650-1Lancaster III, X
Merlin 24, 28, 29, 31, 33, 38 Hurricane, Mosquito, Lancaster, Lancasterian
Merlin 224, 225Lancaster III, X, Mosquito
PD-16B2Merlin 28 ,224Lancaster III, X
PD-16C1Merlin 61
PD-16DlChrysler XI-2220-1, -11
PD-16E1V-1650-1P-40F, L
PD-18AlV-1650 -3, -7North American P-51B, C, D, K, F
Merlin 68, 69Lincoln, Mosquito
PD-18A2V-1650-3, -7North American P-51B,C, D, F, K
PD-18B1Merlin 68, 69Lincoln II, Mosquito
V-1650-7North American P-51D
PD-18C1AV-1650-3, -7North American P-51D, K, TF-51D
PD-18C3A V-1650-9, -9A , -23, -25 North American P-51H, P-82B, C, D
PD-18C4V-1650-9ANorth American P-51H
PD-18D1Merlin 68, 69
PD-18D1AMerlin 68, 69Lincoln II, Mosquito
AR-48D1R-2180-11Piasecki H-16
PR-48A1R-2600-8, -15,-20General Motors TBM-3, Grumman TBF-3, Curtiss SB2C-3, Fairchild SBF-1
PR-48A2 R-2600-15, -20
PR-48A3R-2600-20General Motors TBM-3, PBM-1, Curtiss SB2C
PR-48A4R-2600-29A, -35, -13North American B-25
Sterling V-2500 (Marine)
PR-48B1R-2600-14, -18Grumman F7F-1
PR-52B1Bristol Hercules
PR-53A1P & W X-1800 (XH-2600)
PR-58A1Wright XR-2160 Tornado, R-3350-1
R-3350-8, -10, -12, -14Consolidated P4Y-1, Boeing PBB-l, Douglas SB2D-1, Martin PBM-4
PR-58A3R-3350 -8, -10, -12, -14
PR-58B1V-1710-57 (F11)
PR-58B3 V-3420-13 (A16L), -17 (A18R), -19 (B8), -23 (B10), V-3420 (B4), V-3420-23 (B10), (B11)
V-3420-B4V-3420-23 (B10), (B11)
PR-58B4V-3420-23 (B10)
PR-58B5V-3420-B11, -B12
PR-58C1Lycoming H-2470-2Vultee XP-54
PR-58C2Lycoming H-2470-1, -3, -5, -7Vultee XP-54
PR-58D1Lycoming XH-2470-2, -7
R-2800-22, -28Grumman F7F-2, XF8F-1
R-2800-18W, -22, -28, -34, -36, -57, -61Grumman F7F-2, XF8F-1
R-2800-14W, -18W, -22W, -34WChance Vought F4U-4, AU-1, Grumman F7F, F8F-1, Martin PBM-5
R-2800-CA15Convair 110
R-2800- CA15A, -CA18, -CA18A
R-2800-83AM4AConvair 240
R-2800-83A, -83WAChance Vought F4U-4, AU-1, Grumman F7F, F8F-1, Martin PBM-5
R-2800-18W, -57, -61Chance Vought F4U-4, Republic P-47N
R-2800-14W, -18W, -22W, -34WRepublic P-47N, Fairchild C-82, Northrop P-61
R-2800-55, -57, -61, -73, -77
R-2800-18W,-57,-61Chance Vought F4U-4, Republic P-47N
R-2800-14W,-18W,-22W,-34WRepublic P-47N, Fairchild C-82, Northrop P-61
PR-58E5R-2800-18W, -42WChance Vought F4U-4B
R-2800-C, -42, -CB16
R-2800-CA3, -CA15, -CA18, -CA18AMartin 202, 303, Convair 110, 240, XT-29
R-2800-CA15, -CA15A, -CA18, -CA18ADouglas DC-6
R-2800-95Douglas C-118
R-2800-97Convair T29A, B, VT-29
R-2800-44WNorth American AJ-1, AJ-2
R-2800-48Grumman AF-2
R-2800-50, -50ABell HSL-1, Sikorski S-56, HRS2
R-2800-CB3, -CB16, -CB17Martin 202A, 404
R-2800-CB17Douglas DC-6B, Howard Aero 500
R-2800-CB16Douglas DC-6A, DC-6B, Convair 340, 440
R-2800-52WDouglas C-118A, R6D, Convair R4Y-2
R-2800-99WChase C-123B, Convair C-131A, T-29C, D, VT-29, C-131A
R-2800-CA15Douglas DC-6
R-2800-103WConvair C-131B, D, E, Douglas B-26K
R-2800-52Convair R4Y-1
R-2800-CA18,-97Convair 240, Convair T-29, Brequet 763
R-2800-CB3, -CB6, -CB16, -52WMartin 202A, 404
R-2800-54Sikorski S-56
PR-58F1R-3350-8, -10, -12, -14
PR-58P1 R-3350-57, - 83 Boeing B-29
PR-58P2R-3350-7 49C18BD1 Metering unitLockheed 749
R-3350-745C18EA3, -BA3, -739C18BA3Lockheed 049
R-3350-75, -749C18BD1Lockheed 649, 749, C-121A, B, WV-1
R-3350-749C18BD1Lockheed 749
PR-58P3R-3350-75, -749C18BDl Metering unitLockheed 749, C-121A, B, WV-1
R-3350-749C18BD1, -749C18BA3, -861C18CA2
R-3350-956C18CA, 975C18CBLockheed 1049
R-3350-75, -749C18BD1Lockheed 749, C-121A, B, WV-1
PR-58Q2R-3350-24WALockheed P2V-2
R-3350-24, -35A
PR-58R1Chrysler XI-2220
PR-58S2R-3350-70 Metering unit
R-3350-34, -93, -93ALockheed P2V-3W, R7V-1, WV-2, -3, C-121C, D, G
R-3350-972TC18DA1, 3Lockheed 1049B, C, D
R-3350-972TC18DA2, 4Douglas DC-7
R-3350-975C18CB1Lockheed 1049
R-3350-34, -42 Lockheed P2V-3W, R7V-1, WV-2, -3, C -121C, D, G
R-3350-972TC18DA1, 3Lockheed 1049B, C, E
R-3350-981TC18EAlCanadair CL-28
R-3350-34, -91, -93Lockheed C-121C, D, G
R-3350-988TC18EA1, 3Lockheed 1049G, 1649
R-3350-988TC18EA2Douglas DC-7B, C
R-3350-988TC18EA4Douglas DC-7B, C
R-3350-988TC18EA5Lockheed 1049G, 1649
R-3350-988TC18EA6Lockheed 1049B, C, E
R-3350-93Lockheed C-121D, G, EC-121, RC-121, TC-121
R-3350-972TC18DA1, -DA2, -DA3, -DA4Lockheed 1049B, C, E, Douglas DC-7
R-3350-34,-91Lockheed P2V-3W, R7V-1 WV-2, -3
R-3350-30W, -89A, -89B, -85Fairchild C-119F, G, H, R4Q-2, Lockheed P2V-4, -5, -6
R-3350-30WA, -36WLockheed P2V-4, -5, -6
PR-58U1 R-3350-26, -26WA, -26WB, -26WC, -26WD Lockheed P2V-3, Douglas AD-2, -3, -4, -5, -6, -7, A-1E, F, G, H
PR-62A1Avia (Lycoming) XH-2470
PR-62B1Bristol Hercules XII
PR-62C1Bristol Hercules VIII
PR-62D1Bristol Hercules XII
PR-64B2R-2800-E, 30WGrumman F8F-2
R-2800-32WChance Vought F4U-5
PR-74A1P & W X-1800-C (XH-2600)
PR-78A1Bristol Centaurus
PR-78A2Bristol Centaurus XI
PR-78B1Chrysler XI-2220
PR-88A1P & W XH-3130
PR-100A3R-4360-4, -8Goodyear F2G-1, Martin XBTM-1, JRM-2, Douglas TB2D-1
R-4360-10, -13Boeing XF8B-1, Republic XP-72
PR-100B1R-4360-VSB11GFrench SE-2010
PR-100B2R-4360-VSB11GFrench SE-2010
R-4360-8, -14, -17Douglas TB2D-1, Curtiss XBTC-2, Northrop B-35
PR-100B3R-4360-35, -35ABoeing B-50, C-97, KC-97, Fairchild XC-119A, Douglas XC-124A
R-4360-VSB11G French SE-2010
R-4360-TSB3GBoeing 377
R-4360-27Douglas C-74, DC-7
R-4360-41, -41AConvair B-36B, D, E, RB-36, XC-99
R-4360-20WDouglas C-124A, Fairchild C-119, C-120, Martin XP4M-1, P4M-1
R-4360-35, -35A, -35BBoeing B-50, C-97, KC-97 Fairchild XC-119A, Douglas XC-124A
R-4360-35, -35A, -35C, -59, -59B, -65Boeing B-50, C-97, KC-97
R-4360-TSB5G, 6GBoeing 377
R-4360-B13French SE-2010
PR-100B4R-4360-13B, -25, -35, -TSB3G
R-4360-20, -20WDouglas C-124A, Fairchild C-119, C-120, Martin XP4M-1, P4M-1
R-4360-41, -B13, 27
R-4360-20WC,-20WDDouglas C-124A, B
R-4360-20, -20W, -20WAFairchild R4Q-1, C-119B, C,XC-120, C-120, Martin XP4M-1, P4M-1
R-4360-63A, -63BDouglas C-124C
PR-100D1Lycoming XR-7755-3
PR-100E1R-4360-C, -53
R-4360-53Convair B-36D, E, F, H, J
PR-100E3R-4360-53Convair B-36D, E, F, H, J

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Republic XP-47J (Superbolt)

The classic Republic P-47 "Thunderbolt" fighter of World War 2-fame went through many revisions during its time aloft. Born from the company's work on the P-43 "Lancer", the P-47 entered service with the same "razorback" dorsal spine and large nose-mounted air-cooled radial engine. In time, the "Jug" was advanced to include a bubble-style canopy and higher-performance. Some became true thoroughbreds and excelled at interception duties while others performed exceptionally in the ground-attack role. As either a fighter or fighter-bomber, there were few designs of the war that could match the return-of-investment seen in the American P-47, its design attributed to Alexander Kartveli.

During all this, the U.S. Army was always on the lookout for more of everything and, in November of 1942, contacted Republic to engineer a lighter-weight, higher-performing version of its P-47 (entering official service that same month). This new aircraft would fit an uprated engine in the nose that featured additional cooling and water injection for maximum power at altitude. Weight would be saved wherever possible including armament and fuel. An Army contract issued on June 18th, 1943 covered two XP-47J prototypes.

Engineers returned with a revised form of their P-47 which was designated "XP-47J". The design's engine cowling was refined with a smaller frontal area and this tight cover housed the Pratt & Whitney R-2800-57(C) engine within. The engine outputted at 2,800 horsepower and would drive a standard four-bladed propeller unit. Both the engine and propeller unit were off-the-shelf, in-service products which would aid in mass production of the aircraft. For weight savings, the wing mainplanes were revised to a lighter-constructed form and one of the four machine guns in each wing were deleted (as were some of the internal fuel stores which, in turn, reduced operational ranges). Additionally, some cockpit equipment was removed and the dorsal area aft of the cockpit was cut down. A true bubble-style canopy was not in play as of yet - instead a revised version of the basic P-47 framed canopy was added and this did help in improving vision out-of-the-cockpit for the pilot.

The first XP-47J had its R-2800 engine mounted further ahead in the airframe and the installation was forced-cooled by an intake fan built into in the propeller's spinner. The exhaust ejection system was designed to pull additional thrust from the air flow and the turbosupercharger was aspirated by a new air scoop mounted under the chin of the aircraft.

The second prototype was to feature a true bubble canopy and perhaps a contra-rotating propeller unit to squeeze even more speed out of the design. However, budget issues curtailed its development and it was cancelled in March of 1944.

A first-flight of the XP-47J prototype was had in November 26th, 1943. It did not go airborne again until March of 1944 at which point it revealed itself to be one of the fastest prop-driven aircraft of the period (and the war for that matter) at 500 miles per hour in level flight. During testing on August 4th, 1944, the aircraft - now fitted with the GE CH-5 turbosupercharger - recorded a maximum speed of 505 miles per hour while flying at over 34,500 feet, the fastest speeds ever for a propeller-driven aircraft. Such capabilities gave the XP-47J the nickname of "Superbolt".

Notably, in USAAF hands during testing, the XP-47J is said to never have been able to exceed speeds beyond 493mph.

XP-47J remained a viable fighter development until it was found that another Republic offering, the XP-72 "Ultrabolt" (detailed elsewhere on this site) was showing more promise and more company personnel were appropriately being assigned to this venture instead of the Superbolt. Additionally, Army authorities were put off by the fact that Republic lines would have to be considerably retooled to accommodate mass production for the proposed XP-47J - there was only some 30% commonality of parts between base, in-service P-47 fighters and the proposed XP-47J. As such, this fast fighter prototype born from the P-47 line died before the end of the war in 1945.

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