Mississippi State University XV-11 Marvel
The Mississippi State University XV -11A Marvel (University Internal designation MA -17) was an American STOL experimental aircraft in the 1960s.
History
Background
The origins of the development of the Marvel go back to the year 1950 as the Office of Naval Research commissioned research to studies in the field of boundary layer control of airfoils at the Aero Physics Department at Mississippi State University ( MSU) awarded. The studies lasted until 1962, after which the U.S. Army Transportation Research Command took over this and further led. Purpose of the project was provided by studies with a boundary layer by thousands over the wing of distributed small holes, additionally also played thus combined effect of changes in the profile curvature and the use of a coat propeller an important role. Initially, the University used for the research program a number of different aircraft like a Swiss TG -3A Glider ( registration N64907 ), a Piper YL -21 (USAF serial no. 51-6496 ) and a Cessna L -19A ( 51-11972 ).
It was found, however, that the aircraft used should ideally have a pusher propeller that generates no, with the flow passing over the wing interacts slipstream. As the only such suitable aircraft, the Anderson Greenwood AG -14 was considered to be a single-engine with double tail booms and a pusher propeller. On 27 June 1955, the MSU procured, therefore, the fourth produced a total of six AG -14 ( N3903K ), which subsequently received a covering of the pusher propeller. In this configuration, 20 flight hours, but then sold again, because there is no certificate of airworthiness ( airworthiness certificate ) could be obtained.
Marvel
Now a completely new airfoil structure was regarded as necessary to achieve full impact of the boundary layer and also the profile curvature. In addition, the use of fiberglass was observed for the airfoil as necessary to maintain the surface roughness as small as possible. With these specifications the Mississippi Aero Physics Research Vehicle Extended Latitude was briefly referred to by the acronym MARVEL and the Mississippi Aero Physics Studies no. MA -17 was carrying.
However, it quickly became clear that advance the suitability of the proposed machine has to be proven for the tests laid down by a smaller and weaker test machine. For this purpose the Marvelette ( diminutive of Marvel ) based on the fourth produced AG -14 ( N3901K ) was built and flown for the first time on 16 November 1962. The test flights were continued until March 1964, with landing speeds of 56 km / h and a top speed of 200 km / h were achieved.
The first flight of the Marvel took place on 1 December 1965. The machine received the USAF / Army serial number 65-13070. The flight test program included 49 first flights with a duration of 35 hours, which were completed by April 1967. The flights show a disappointing impact of boundary layer control, there were not sufficient, the suction speeds of the wing in order to prevent flow separation, especially in curvatures about 10 degrees. The increase in inflation has been very low. Until the expiry of formal U.S. Army contract 100 flight hours were completed, with maximum speeds of 330 km / h and lowest -off distances of 38 m were determined.
Marvel II
The aircraft was then shut down until 1981, when the company Biroc Ltd.. from Arlington (Virginia) awarded a contract to the MSU for concept study for a multipurpose aircraft desert. Expected results were the applicability to soft sand tracks, low infrared signature, and low radar backscatter.
The necessary modifications to the Marvel related primarily to the wings, which were re-established with a Kevlar skin. Also, the engine was replaced with an improved version of T63, which is now delivered 420 hp. The propeller is now also consisted of Kevlar. The aircraft was re-registered as N2768Q on June 11, 1982, now referred to as Marvel II. After 21 flights in the U.S., the shipping was to Saudi Arabia, where the first flight took place on 15 November 1982 in Taif. After only two flights, the Marvel II was transported back to the U.S., since it was found that the set aims of the investigation could not be reached. In the years 1987 to 1989 were still occasionally flights, on air shows performed.
Construction
The Marvel was constructed almost entirely of glass fiber materials, only to gain individual components were made of steel, made particularly in the area of the Allison T63 turboprop engine. For gluing the fiberglass parts were epoxy resins and used as filler polyurethane foam. The GRP spar had to reinforce individual layers of steel, otherwise the wings were made entirely of fiberglass. The curvature could with a special electrically driven mechanism of wing twist ( wing warping ), which reached about half the wingspan to be changed up to 30 degrees.
For the generation of the vacuum for the boundary layer control the installation of an auxiliary power unit Solar T62 was originally intended, but was in the practice of driving the compressor through the main engine. In the casing of the propeller also height and rudder were integrated, with the elevator projected beyond the edge of the mantle. The Allison T63 turbine was installed in a steel box, which also took care of the necessary fire foreclosure. The power was transmitted through a 2.10 m long distance shaft of a reduction gear, and a constant speed propeller.
The supply of air for the engine was carried out by the air sucked in influencing the boundary layer and by small inlets on the wing leading edge. The chassis had an unusual design with four wheels, each of which was arranged in two tandems in a kind of skid. The front wheel was each controllable. This Panta Base -mentioned arrangement should ensure good start- off and landing performance on soft ground. The appearance strongly resembled the construction of the Vincent Burnelli for his Uppercu - Burnelli GX -3 in the late 1920s had chosen.