The Interstate Cadet was an American two-seat tandem, high wing, single-engine

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

light aircraft. Around 320 of these aircraft were produced between the years 1941 and 1942 by the

Interstate Aircraft and Engineering Corporation Interstate Aircraft and Engineering Corporation was a small American aircraft manufacturer in production from April 1937 to 1945, based in El Segundo, California. History Originally known as Interstate Engineering, the company became the Int ...

based in El Segundo,

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. The construction techniques employed were a welded steel tube

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

, wood (spruce) wing structure with metal ribs, and fabric covering, all of which were fairly standard in the 1940s. An Interstate Cadet, flown by aviator

Cornelia Fort Cornelia Clark Fort (February 5, 1919 – March 21, 1943) was a United States aviator who became famous for being part of two aviation-related events. The first occurred while conducting a civilian training flight at Pearl Harbor on December 7, 1 ...

and an unknown student, was one of the first aircraft (if not the first) to be attacked by

IJNAS The was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired their first aircraft in 1910 a ...

Japanese naval planes en route to the

Pearl Harbor Pearl Harbor is an American lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. It was often visited by the Naval fleet of the United States, before it was acquired from the Hawaiian Kingdom by the U.S. with the signing of the Re ...

attack on December 7, 1941.

Design and development

The original version, the S1 prototype, was powered by the 50 hp

Continental A50 The Continental O-170 engine is the collective military designation for a family of small aircraft engines, known under the company designation of A50, A65, A75 and A80. The line was designed and built by Continental Motors commencing in the 194 ...

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...

, but was soon upgraded to the

Continental A65 The Continental O-170 engine is the collective military designation for a family of small aircraft engines, known under the company designation of A50, A65, A75 and A80. The line was designed and built by Continental Motors commencing in the 194 ...

engine and redesignated as the S1-A-65F. This was a common engine used in many small American two-seat aircraft of the time. This aircraft would be used during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

under the L-6A designation. In 1945 the rights to the aircraft were sold to

Harlow Aircraft Company Harlow Aircraft Company was an American aircraft manufacturer at Alhambra Airport, Alhambra, California. History The company was founded in 1936 by professor Max B. Harlow to build the Harlow PJC-2 a production version of the PJC-1. The aircraf ...

, which in turn resold the tooling and parts to the

Call Aircraft Company The Call Aircraft Company (CAC or CallAir) was established by Reuel Call in 1939 at Afton, Wyoming to build a touring aircraft of his own design. History The Call Aircraft Company hoped to advance the development of its CallAir Model A to the poin ...

Afton, Wyoming Afton is a town in Lincoln County, Wyoming, United States. The population was 1,911 at the 2010 census. Afton is home to the world's largest arch made of elk antlers. Spanning across the four lanes of U.S. Highway 89, the arch consists of 3,011 ...

in 1946 for $5,000 ($ in ). Callair rebuilt a number of S-1, S-1A and L-6s, some with engine upgrades, for local ranchers and bush pilots as well as two examples of their own serial numbered CallAir S-1A-90C before stopping production, focusing instead on variations of its original

CallAir Model A The Call-Air Model A is an American two- to three-seat utility aircraft designed by the Call brothers and built by the Call Aircraft Company, later developed into a successful line of agricultural aircraft. Design and development The Model A was ...

(which also sold in small numbers, fewer than 200 total units)., One reason the Cadet may not have sold well was that this aircraft cost almost three times the amount of the comparable

Piper J-3 Cub The Piper J-3 Cub is an American light aircraft that was built between 1938 and 1947 by Piper Aircraft. The aircraft has a simple, lightweight design which gives it good low-speed handling properties and short-field performance. The Cub is Pi ...

. However, a close look at the two aircraft reveals that the Cadet was faster, stronger, and could be operated in a more rugged environment with its Oleo strut/Compression spring suspension system. Popular upgrades for this airframe included larger engines(75/85/90/100 hp), better brakes, and a different

tailwheel Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Terms ...

system. In the late 1960s the

type certificate A type certificate signifies the airworthiness of a particular category of aircraft, according to its manufacturing design (''type design''). It confirms that the aircraft of a new type intended for serial production, is in compliance with applica ...

s and tooling were bought by the newly formed

Arctic Aircraft __NOTOC__ The Arctic Aircraft Company was founded in Anchorage, Alaska by Bill Diehl in 1975 to produce an updated version of the Interstate Cadet light aircraft as the Arctic Tern. In 1985 The year 1985 was designated as the Internatio ...

Company who transformed the S-1B1 into a bush plane by upgrading structural elements of the fuselage, landing gear and wings. This aircraft was designated the S-1B2, was used a

Lycoming O-320 The Lycoming O-320 is a large family of naturally aspirated, air-cooled, four-cylinder, direct-drive engines produced by Lycoming Engines. They are commonly used on light aircraft such as the Cessna 172 and Piper Cherokee. Different variants ...

160 HP engine and a McCauley propeller for increased performance and was certified in 1975 as the

Arctic Tern The Arctic tern (''Sterna paradisaea'') is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe (as far south as Brittany), Asia, and North America (as far south a ...

. The new Type certification also covered installing the same engine in otherwise standard Interstate Cadets.

Variants

;S-1 :Certified in 1940 and powered by a

Continental A50-8 The Continental O-170 engine is the collective military designation for a family of small aircraft engines, known under the company designation of A50, A65, A75 and A80. The line was designed and built by Continental Motors commencing in the 194 ...

engine. ;S-1A :Certified in 1941 and powered by a

Continental A65-8 The Continental O-170 engine is the collective military designation for a family of small aircraft engines, known under the company designation of A50, A65, A75 and A80. The line was designed and built by Continental Motors commencing in the 194 ...

engine.

;S-1A-65F :1941 variant powered by a 65hp

Franklin 4AC-176-B2 The Franklin O-175 (company designation 4AC-176) was an American air-cooled aircraft engine of the 1940s. The engine was of horizontally-opposed four-cylinder and displaced . The power output was nominally . A later variant was designated O- ...

engine. ;S-1A-85F :1942 variant powered by an 85hp Franklin 4AC-199-D2 engine. ;S-1A-90C :1952 Callair variant powered by a 90hp

Continental C90-8 The Continental C90 and O-200 are a family of air-cooled, horizontally opposed, four-cylinder, direct-drive aircraft engines of 201 in³ (3.29 L) displacement, producing between 90 and 100 horsepower (67 and 75 kW).''Federal Aviation Admin ...

engine.only two built. ;S-1A-90F :1942 variant powered by 90hp Franklin 4AC-199-E2 engine. ;S-1B1 :1942 variant with a Franklin 4ACG-199-H3 engine. Military production as the L-6 Grasshopper. ;S-1B2 (

) :1975 improved variant of the S-1B1 powered by a Lycoming O-320-A2B or B2B engine. ;XO-63 Grasshopper :United States Army designation for one S-1B for evaluation, later designated the XL-6. ;L-6A Grasshopper :United States Army designation for the S-1B1, 250 built. ;L-8A Cadet :United States Army designation for eight S-1As ordered on behalf of the Bolivian Air Force.

Specifications (S-1B1)

References

;Notes ;Bibliography * {{USAAF observation aircraft Interstate aircraft 1940s United States civil utility aircraft High-wing aircraft Single-engined tractor aircraft Aircraft first flown in 1940

Design and development

Variants

Specifications (S-1B1)

See also

References