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Lockheed YP-24

Monoplane Fighter Prototype Aircraft

The YP-24 marked the first fighter attempt by the storied Lockheed concern - though events led to just a single prototype being completed and this example crashing before the end of 1931.
Authored By: Staff Writer | Edited: 5/9/2019
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Year: 1931
Status: Cancelled
Manufacturer(s): Detroit Lockheed - USA
Production: 1
Capabilities: Fighter; X-Plane;
Crew: 2
Length: 28.71 ft (8.75 m)
Width: 42.81 ft (13.05 m)
Height: 8.53 ft (2.6 m)
Weight (Empty): 3,009 lb (1,365 kg)
Weight (MTOW): 4,365 lb (1,980 kg)
Power: 1 x Curtiss V-1570-23 "Conqueror" V12 liquid-cooled inline piston engine developing 600 horsepower and driving three-bladed propeller unit at nose.
Speed: 236 mph (380 kph; 205 kts)
Ceiling: 25,000 feet (7,620 m; 4.73 miles)
Range: 559 miles (900 km; 486 nm)
Rate-of-Climb: 1,820 ft/min (555 m/min)
Operators: United States (cancelled)
Lockheed's first foray into military fighter aircraft design and development became the developmental "YP-24". This aircraft existed only as a prototype form for the duration of its life and took on the appearance of a two-seat fighter for possible adoption by the United States Army Air Corps (USAAC). A first-flight was had in 1930 but the program was hit by several events out of its control which curtailed manufacture to just one example completed.

The aircraft was designed by Robert J. Woods and construction handled primarily by the Detroit Aircraft Corporation as a private venture work. It was based on the Lockheed "Altair" of 1930 which was developed for civilian sport. This product, itself, was based on the Lockheed "Sirius" utility transport of 1929 (designed by Jack Northrop and Gerard Vultee - later of Northrop and Vultee aircraft respectively).

The YP-24 became a sleek, low-wing monoplane with retractable tail-dragger undercarriage and enclosed cockpit. The crew was seated in tandem with a machine gun fitted to the rear cockpit atop a trainable mounting. The tail unit was of a traditional single-finned arrangement. The engine, fitted at front, drove a three-bladed propeller unit. The fuselage was constructed of metal and the wings made up of wood. Detroit Aircraft provided the former with Lockheed engineers delivering the latter sections.

Testing of the "XP-900" prototype occurred at historic Wright Field in Southwest Ohio. The prototype managed a maximum speed of 235 miles per hour with cruising nearing 215 mph. Range was out to 556 miles and the service ceiling reached 25,000 feet. Rate-of-climb measured 1,820 feet per minute.

From this work, the USAAC became interested enough to purchase the aircraft for its own testing ventures. This led to a redesignation of the XP-900 aircraft to YP-24. The subsequent period yielded a contract for five aircraft in a fighter guise as the Y1P-24 and four in an attack-minded guise as the Y1A-9.

The base fighter design was to carry 1 x 0.50 caliber heavy machine gun in the nose firing through the spinning propeller blades (a synchronizer handled the rate). This weapon was paired with 1 x 0.30 caliber medium machine gun. The rear gunner managed 1 x 0.30 caliber machine gun. The aircraft's drive power came from a Curtiss V-1570-23 "Conqueror" V12 liquid-cooled inline piston engine of 600 horsepower.

The attack model was proposed with a battery of 4 x machine guns fixed, firing forward for attack runs. It would also be outfitted with underwing racks for carrying conventional drop ordnance. One other major difference was an engine substitution to the Curtiss V-1570-27 inline piston series - the powerplant selected for its better low-level performance.

All was derailed when, in October of 1931, the single prototype crashed following an undercarriage failure (one of the main legs getting stuck in flight; the test pilot bailing out). This coupled with a weakening global economy (forcing both Detroit Aircraft and Lockheed into bankruptcy) led to the YP-24 program's demise as a prominent future USAAC player.

Despite the major setback, Woods continued work on the aircraft under the Consolidated brand label in the period following, leading to the "P-30" monoplane fighter of 1934. Sixty of these were built and flown by the USAAC prior to World War 2 (1939-1945).


Fighter Variant:
1 x 0.50 caliber heavy machine gun in nose, synchronized to fire through the spinning propeller blades.
1 x 0.30 caliber medium machine gun in nose, synchronized to fire through the spinning propeller blades.
1 x 0.30 caliber medium machine gun in rear cockpit on trainable mounting.

Attack Variant:
4 x 0.30 caliber machine guns in fixed, forward-firing mountings.
1 x 0.30 caliber medium machine gun in rear cockpit on trainable mounting.

Provision for underwing stores (conventional drop bombs).

Graphical image of an aircraft medium machine gun
Graphical image of an aircraft heavy machine gun
Graphical image of an aircraft conventional drop bomb munition

Variants / Models

• XP-900 - Wright Field prototype designation; single example completed.
• YP-24 - USAAC designation for single prototype
• Y1P-25 - Designation for proposed fighter model; V-1570-23 inline engine of 600hp; armament of 1 x 0.50 cal and 1 x 0.30 cal machine guns in nose, 1 x 0.30 cal machine gun in rear cockpit.
• Y1A-9 - Designation for proposed attack model; Curtiss V-1570-27 inline engine; 4 x machine guns in fixed, forward-firing mounts, underwing racks for conventional drop stores.
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