Abrams P-1 Explorer

The Abrams P-1 Explorer was American purpose-designed aerial photography and survey aircraft that first flew in November 1937.

P-1 Explorer
Role aerial photography and survey aircraft
National origin United States
Manufacturer Abrams Aircraft Corporation
Designer Talbot Abrams
First flight November 1937
Number built 1

Design and development

The Explorer was designed by aerial survey pioneer Talbert Abrams to best suit his needs for a stable aircraft with excellent visibility for this kind of work. Abrams was an early aerial photographer in World War I. He used a Curtiss Jenny post-war forming ABC airlines. In 1923, Abrams founded Abrams Aerial Survey Company and in 1937, Abrams Aircraft Corporation to build the specialized P-1 aircraft.[1]

The standard single front-engined airplane of this era created many problems for good scientific photography. They were created to be very nimble in the air rather than stable photographic platforms. Their engines leaked oil which would then flow under the aircraft and get on the camera lens. The engines were noisy making cockpit conversation difficult.

The designer of the Abrams P-1 Explorer conceived an aircraft with a rear engine to keep the camera apertures clean and reduce cockpit noise and using a delta type wing so side vision was possible. He hired engineers, Kenneth Ronan and Andrew Edward Kunzl, in Marshall, Michigan, who drew plans and began construction in the old Page Brothers Buggy Company factory.

Ronan and Kunzl operated an aeronautical repair station at the Marshall airfield. Ronan was in the first graduating class of aeronautical engineering from the University of Michigan. Careful planning and ten months of construction produced an airplane capable of more efficient and economical aerial photography.

To create the clear nose so the pilot had unobstructed view, he called in the German company of Rohm and Haas, creators of Plexiglas. With a wooden male model of each window pane, the Plexiglas was clamped in a frame much like a window frame. When heated until it began to sag, it was pushed down by two workers holding the frame until it was molded to the wooden model.

The Plexiglas could then be trimmed and mounted in the frame work. When the Explorer came back for restoration, it was those panels which had been heated which survived the years as clear as when new. However, through some abuse during disassembly, they were destroyed.

It was a low-wing metal monoplane with twin booms and a central nacelle for the pilot and camera equipment. The pod's nose section was extensively glazed in Plexiglas. The undercarriage was fixed and of tricycle configuration.

Originally powered with a 330 hp (250 kW) engine and a two-bladed propeller it was sent back to Ronan & Kunzul to increase the horsepower to 450. This change required braces to be added from the wing top to the fuselage and they added a three-bladed propeller. Ted thought the increased power would bring a buyer to his airplane.

World War II interrupted Abram's work and the single aircraft built was put into storage for the duration of the war. Obsolete by the end of the conflict, it was donated to the US National Air and Space Museum in 1948 where it remains today awaiting restoration.

Variants
P-1
the initial design and prototype.
PC-4
Abrams planned a pressurized version of the P-1, named the PC-4 that did not go into production.[2]

Operational history

The P-1 was flown with a variety of camera gear. The Abrams Instrument Corporation C-3 camera was used to produce 650 nine by nine inch photos per flight.[2]

In 1968 a number of aviation friends met for lunch including Jim Linn who worked at Abrams Aerial Survey. He mentioned the Explorer and no one in the room had heard of it except one. Ron Dietz, who was a student pilot at that time, went to his car and returned with the May issue of the Private Pilot magazine. Here was a big story with photos of the aircraft.

The idea began that perhaps it was time for Lansing to do something for Mr. Abrams, who often provided financial support when asked. Ellis Hammond, President of the Michigan Aerospace Educational Association and Ron Dietz, engineer at Oldsmobile Division of General Motors, decided to put some time and money into the project.

Having worked with the Smithsonian's National Air and Space Museum's Assistant Director Don Lopez, the aircraft was released. In January 1975 the Explorer was transported in a Michigan National Guard C130 to the Capital Region International Airport|Capital City Airport in Lansing, Michigan.

The aircraft was moved to a state owned hangar where Dietz was in charge of careful photography before any disassembly was done. He carefully made tracings of all the lettering so they could be faithfully redone at the end of the project.

The wings were sent to Montcalm Community College where they were carefully stripped, cleaned, repainted and recovered with silver painted fabric. The instruments panels and controls were disassembled and restored by Mr. Dietz's colleagues at Oldsmobile.

The aircraft was physically moved to the Lansing Community College aviation program where I lost daily contact with it. During a visit to the airport Hammond and Dietz lamented at the lack of attention and the shortage of restoration work versus repair work on the aircraft. They agreed to cancel their support of the airplane with the Smithsonian and suggested it was best for all to have the plane returned. In 1981 the Lansing Community College truck driving school took the plane back to Silver Hill, Maryland, where it is today.

Specifications
Abrams Explorer 3-view drawing from L'Aerophile March 1938

Data from Jane's all the World's Aircraft 1938[3]

General characteristics

  • Crew: 2
  • Length: 26 ft 6 in (8.08 m)
  • Wingspan: 36 ft 8 in (11.18 m)
  • Height: 6 ft 4 in (1.93 m)
  • Wing area: 200 sq ft (19 m2)
  • Aspect ratio: 6.58
  • Airfoil: root: NACA 23018; tip: NACA 23009[4]
  • Empty weight: 2,100 lb (953 kg)
  • Gross weight: 3,400 lb (1,542 kg)
  • Powerplant: 1 × Wright R-975E-1 Whirlwind 9-cylinder air-cooled radial piston engine, 365 hp (272 kW)
  • Propellers: 2-bladed Hamilton-Standard variable-pitch pusher propeller

Performance

  • 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
  • Range: 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)
  • Power/mass: 9.3 lb/hp (5.7 kg/kW)

See also

Related lists

References
  1. Miller, Ron (2008). Extreme aircraft (1st ed.). Harper Collins. ISBN 9780060891411.
  2. Robert F. Pauley. Michigan Aircraft Manufacturers.
  3. Grey, C.G.; Bridgman, Leonard, eds. (1938). Jane's all the World's Aircraft 1938. London: Sampson Low, Marston & company, ltd. p. 242c.
  4. Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
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