Arup (plane)

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Arup
Arup S-2
Arup S-2
Type:
Design country:

United StatesUnited States United States

Manufacturer:

Arup Manufacturing Corporation

First flight:

1932 (S-1), April 1933 (S-2), July 15, 1934 (S-3), March 19, 1935 (S-4)

Number of pieces:

4th

Arup was the common name for a family of aircraft from the 1930s that were designed as tailless aircraft , with the wing each having a semicircular floor plan. A total of four different machines were made by Arup Manufacturing Corporation , the one designed by Cloyd Snyder, an American podiatrist based in South Bend, Indiana .

history

The unusual wing layout of the Snyder designs goes back to an incident in 1926 when he threw a semicircular felt shoe insert over his desk and found that it showed significant lift in flight. Snyder then carried out systematic investigations into the extent to which this shape could be suitable as a wing for an aircraft. For this purpose, he used small, non-powered balsa wood models with a semicircular wing plan, which were driven by a rubber motor and which showed good flight stability even at large angles of attack .

Snyder's goal was to develop an aircraft with a wing of 100 ft. (30.5 m) wingspan, 100 ft. Area depth and a thickness of 15 ft. (5 m). In the flying wing, the passengers were to be accommodated within the wing and had a good view of the outside through the glazed leading edge. The Junkers G 38, flown for the first time in 1929, had a similar arrangement with passenger seats in the leading edge of the wing .

Glider (subsequently Arup S-1)

After applying for some patents related to his development project, Snyder began building larger models, which he mounted on the roof of his car and watched while driving. He also used a wind tunnel at the University of Michigan . For the construction of the first man-carrying test aircraft, he teamed up with the works teacher from the local high school , who took over the construction with his students, while Snyder himself took over the construction and procurement of the material. In the spring of 1932, the first attempts at taxiing and the first unintentional short flight of the glider took place using a car as the towing vehicle.

Since Snyder was not a pilot himself, Glen Doolittle made 40 flights on his behalf before considering the first flight in front of a larger audience. This happened on June 12, 1932, when some film reporters shot the glider in flight in South Bend.

Motorized glider

The next development stage was the installation of an engine in the glider, which Snyder commissioned Raoul Hoffman. The Henderson Heath engine used was supposed to develop 26 hp, but rarely delivered this power. It was already clear after the first flight attempts that the machine was not a great success. A strong pressure point migration and unreasonably high rudder forces could be determined. The obvious conclusion was therefore to develop a completely new machine.

Arup S-2

To build and finance the project, Snyder founded the Monowing Corporation . However, the funds were raised before the construction work was finished, and a new company was to be formed. The phonetic contraction of the terms air and up to Arup was chosen as the name. The glider was retrospectively given the name Arup No.1 or S-1.

The Arup No.2, mainly referred to in the literature as the S-2 or S-35, had a slim fuselage and a conventional vertical stabilizer that replaced the previous design of two separate stabilizers. Hoffman, who did the major engineering work, chose a NACA M-6 wing profile to limit pressure point drift and also made extensive modifications to the previous design. The roll stability could be improved by two small ailerons attached to the wing tips. The pilot boarded the aircraft through a trap door at the bottom. The drive consisted of a Continental A-40 with 36 hp. Based on the available power, the aircraft mass was relatively high at 780 lb (354 kg). The wing had a span and depth of 16 ft (5 m) each. Including the additional ailerons, the wingspan was 19 ft (6 m). The top speed was about 97 mph. And the landing speed was 23 mph. Doolittle, who also tested this aircraft, found the flight characteristics to be good.

In mid-1933, the Civil Aeronautics Authority (CAA) was looking for new proposals for its flivver-plane concept of a small and cheap airplane after the Ford Flivver had not been pursued after a crash. The Arup project funders decided that Snyder and Doolittle should demonstrate the Arup No.2 in Washington. Little is known about the result, but the No.2 representatives from the US Army Air Forces , US Navy , CAA and NACA could even be shown in flight over the Washington Monument .

Arup S-3

Back in South Bend, work should begin on a two-seater version. Due to an illness of Raoul Hoffman, which suggested a move to warmer Florida, he moved to St. Petersburg and built his own machine there on behalf of J. Leslie Younghusband (registration number NX11573), which was designed very similar to the Arup. The result was a two-seater monoplane with an 85 HP Cirrus III engine. Due to a defective fuel line, a fire started during a flight, which led to the crash of the machine, in which Hoffman was killed.

Ralph Graichen was hired to replace him as a designer, but his ideas about the design of the future machine were clearly different from Snyder's. Graichen was able to assert himself here, as the construction was also relocated to Indianapolis, the influence of Snyder on the construction of No.3 sank considerably. After being transported to South Bend, Doolittle made the maiden flight there. The aircraft's overall performance, however, proved disappointing for an 85hp aircraft and it stayed with that one flight. When an arson attack was carried out on the uninsured machine one night, which also destroyed the production facilities, it was a serious setback for the company.

Arup S-4

Shortly afterwards, a pilot from Detroit placed an order for a new design, but the funds provided were already used up halfway through the construction phase. Bendix then provided the chassis and O'Brien Paints provided the paint so that the machine could still be completed. Since the original client went bankrupt, the aircraft should be sold elsewhere, which proved difficult. Test flights were carried out in the summer of 1935, with the flight behavior and performance being assessed as good.

On the one hand, the S-4 was used for advertising purposes, in that the top of the wing was provided with advertising slogans and political slogans like a billboard. However, it also appeared at air races and air shows and demonstrated its short take-off and landing properties. However, the depression that prevailed at the time forced the company to shut down and the plane was scrapped. No data from the S-4 has survived.

Aftertaste

There were no incidents or injuries to the pilots on any of the flights of the four aircraft. Dr. Snyder went to Goodyear after Arup's bankruptcy , where he retired from work shortly after World War II. He died on November 6, 1971.

Technical specifications

Parameter Data S-1 Data S-2 Data S-3
crew 1 1
length 4.30 m 5.20 m 5.33 m
span 6.10 m 5.80 m 6.70 m
Wing area 19.6 m² 25.4 m²
Empty mass 354 kg
Top speed 156 km / h
Engines 1 × Heath-Henderson B-4, 26 PS (19 kW) 1 × Continental A-40, 36 PS (27 kW) 1 × LeBlond 5DE, air-cooled five-cylinder radial engine, 70 PS (52 kW)

See also

literature

  • Bernard L. Rice: Those amazing Arups . In: Airplane Monthly July 1979, pp. 340-345

Web links

Commons : Arup aircraft  - collection of images, videos and audio files

Individual evidence

  1. ↑ Airplane Monthly July 1979, p. 343.
  2. ↑ NACA profile M6
  3. ↑ flivver stood for a small, cheap automobile in US slang of the 1920s
  4. ↑ Description and data of the S-3