Republic AP-47 (Army Project 47)

History

The land-based warfare of World War II (1939-1945) relied heavily on large formations of tanks and other armoured fighting vehicles, suggesting that American war planners needed air service to deploy competent ground attack/support platforms. Various Various fighters were played as fighter-bombers, with some specialized attackers mixed in. In the postwar world, as the jet age progressed month by month, engineers had a "white canvas" to develop entirely new types of aircraft.

Due to the inherent limitations of early jet technology, "hybrid" aircraft (combining a propeller engine with a jet or rocket engine) were considered, and one of those entering the field was the "AP-47". (AP = Republic Aviation's "Army Program".

During the war, the Republic was known for its classic and versatile P-47 Thunderbolt, a single-engine, single-seat aircraft affectionately known as the "Jug" due to its deep fuselage . Equipped with 8 x .50 caliber heavy machine guns for standard stationary armament, the platform was quickly found to have excellent qualities as a light bomber, capable of carrying dropped bombs or rockets into battle. Over time, this fighter-bomber was pulled from U.S. inventories as more advanced aircraft began to take center stage.

Unlike other wartime propeller-driven aircraft that continued to serve in the coming Korean War (1959-1953), the Thunderbolt did not receive an extended service life and was eventually retired.

Back in September 1948, during the decade of hybrid-engine aircraft, the Republic was trying to get the United States Air Force (USAF) interested in new ground attack platforms like the AP-47 mentioned above. Designed for ground support missions, the aircraft inherits some of the proven qualities of the original P-47, including a four-bladed propeller unit and primary armament consisting of an 8 x .50 caliber heavy machine gun. The teardrop canopy is designed to provide excellent visibility for the aircraft, and the cockpit is forward amidships. The propeller engine is mounted on the nose in front of the pilot, and the turbojet is located in the rear of the fuselage, sucking in air through chin-mounted blades and expelling thrust through openings under the tail. There is only one rudder at the stern, and the level is set low.

The main-wing aircraft are reminiscent of the P-47, to be precise in their general appearance (top to bottom) with rounded tips.

The fuselage is well contoured, tapering from nose to tail for a smooth appearance. The canopy has a low height to reduce drag in the frontal area and is positioned to give the pilot a good attack visibility, especially when diving into the target/target area.

Unlike the more modern jet fighters of the time (and today, for that matter), the AP-47 was supposed to have old-fashioned "trailing" landing gear for ground operations.

The engines chosen were a Pratt & Whitney R-2800 Double Wasp mounted in the nose and a Westinghouse 24C turbojet mounted in the aft fuselage. Propeller engines can produce up to 2,500 horsepower, and jets have up to 3,000 pounds of thrust.

The aircraft should be able to fly with one engine turned off, but the combined performance guarantees excellent performance - limited primarily by technology, fuel and airframe.

The plane's wingspan should be 41 feet 6 inches, but few people know about other numbers, like Jet, which is the thirstiest of the two.

In the end, the US Air Force authorities did not believe in the merits of this hybrid-engine attack aircraft and had no interest in pursuing the design, leaving it to the chapters of military aviation history. The United States Navy (USN) has had slightly greater success with the hybrid engine design of the Ryan FR "Fireball" described elsewhere on this site. About 71 of these aircraft have been completed.

The successor, the XF2R "Dark Shark," fared even worse, with only one prototype built, but by then, jet-only thoroughbreds were the way of the future.

There were of course other hybrid engine designs in the interim, but advances in jet technology quickly dimmed the prospects for such an aircraft.

The performance figures on this page are the authors' estimates.

Specification

Basic

Production

Roles

Dimensions

Weight

Performance

Performance

Armor

Changes