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Abrams P-1 Explorer

The Abrams P-1 Explorer, an aerial photography and survey aircraft, was specifically developed in the United States.

It successfully completed its maiden flight in November 1937.

Talbert Abrams, a renowned figure in aerial surveying, was the mastermind behind the design of this aircraft.

His primary objective was to create a stable aircraft that offered exceptional visibility, catering to the requirements of his work.

Notably, Abrams had already established himself as an early aerial photographer during World War I.

Following the war, he utilized a Curtiss Jenny aircraft and subsequently founded ABC airlines.

Abrams established the Abrams Aerial Survey Company in 1923, followed by the Abrams Aircraft Corporation in 1937, with the purpose of constructing the specialized P-1 aircraft.

During this time, the conventional single front-engined airplanes commonly used for scientific photography had several limitations.

These aircraft were primarily designed for agility in flight rather than serving as stable platforms for photography.

One of the major issues was the tendency of their engines to leak oil, which would then seep beneath the aircraft and negatively impact the camera lens.

Additionally, the loud engines posed a challenge for communication within the cockpit.

To address these concerns, Abrams devised an innovative aircraft design featuring a rear engine configuration.

This arrangement ensured that the camera apertures remained free from contamination and reduced the noise level in the cockpit.

Furthermore, Abrams incorporated a delta type wing, which enhanced side vision capabilities for improved photographic accuracy.

In Marshall, Michigan, engineers Kenneth Ronan and Andrew Edward Kunzl were hired by Abrams to work on the construction of an airplane in the former Page Brothers Buggy Company factory.

Operating from the Marshall airfield, Ronan and Kunzl also ran an aeronautical repair station.

The planning and construction phase lasted for ten months, resulting in the development of an aircraft specifically designed for more efficient and cost-effective aerial photography.

To ensure an unobstructed view for the pilot, Abrams enlisted the services of the German company Rohm and Haas, renowned for their creation of Plexiglas.

The process involved clamping the Plexiglas in a frame, similar to a window frame, along with a wooden model of each windowpane.

The material was then heated until it began to soften, at which point two workers would push it down using the frame, moulding it to the shape of the wooden model.

Once moulded, the Plexiglas could be trimmed and mounted within the framework.

Remarkably, when the Explorer aircraft returned for restoration, the previously heated panels remained as clear as when they were new, despite being subjected to abuse during the disassembly process.

The Explorer, an aircraft of remarkable design, featured a low wing made of aluminium, along with twin booms and a central nacelle that housed both the pilot and the camera equipment.

Notably, the nose section of the pod was extensively glazed with Plexiglas, allowing for enhanced visibility.

Its undercarriage, in a fixed configuration, adopted a tricycle layout.

Initially, the aircraft was equipped with a 330-horsepower engine and a two-bladed propeller.

However, in an effort to increase its power output to 450 horsepower, it was sent back to Ronan & Kunzul.

To accommodate this modification, additional braces were installed from the wing top to the fuselage, and a three-bladed propeller was fitted with the hopes of attracting potential buyers.

Unfortunately, the outbreak of World War II disrupted Abrams’s progress, and the sole aircraft constructed was subsequently stored for the duration of the war.

26 ft 6 in (8.08 m)
36 ft 8 in (11.18 m)
6 ft 4 in (1.93 m)
Wing area
200 sq ft (19 m2)
Aspect ratio
NACA 23018
NACA 23009
Empty weight
2,100 lb (953 kg)
Gross weight
3,400 lb (1,542 kg)
1 × Wright R-975E-1 Whirlwind,
9-cylinder air-cooled radial piston engine,
365 hp (272 kW)
2-bladed Hamilton-Standard variable-pitch pusher propeller
Maximum speed
200 mph (320 km/h, 170 kn) at 10,000 ft (3,000 m)
Cruise speed
175 mph (282 km/h, 152 kn) at 10,000 ft (3,000 m)
Landing speed
60 mph (52 kn; 97 km/h) with flaps extended
1,200 mi (1,900 km, 1,000 nmi)
Service ceiling
20,000 ft (6,100 m)
Rate of climb
1,400 ft/min (7.1 m/s)
Wing loading
17 lb/sq ft (83 kg/m2)
9.3 lb/hp (5.7 kg/kW)
Charles Daniels Photo Collection.
Jane’s all the World’s Aircraft 1938.

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