Aircraft Designed by the TumenEcotrans Open Joint-Stock Company

This is a report on the technical proposal to develop a light off-airfield operational aircraft with a 2000 kg all-up weight and a five to six passenger capacity. The earlier TumenEcotrans OJSC concept of a superheavy aerostatic transport aircraft with an aerodynamic unloading capability has not been studied.

This assessment report is based upon the following documents:

1. The report made at the SibNIA by the TumenEcotrans OJSC Designer-in-Chief A.I.Filimonov on Apr.11, 2001.

2. The business plan for the "Bella" - aircraft of an off-airfield basing and operations designed by A.I.Filimonov. 2001.

3. The report by the SibNIA technical commission on the results of a technical evaluation of the experimental aircraft of A.I.Filimonov design. 1995.

4. The A.I.Filimonov experimental aircraft log issued by the SibNIA technical commission in 1995.

5. The report by the TumenEcotrans CYSC on the research poject "Development of A.I.Filimonov Designed Aircraft". 1995.

6. The assessment report by the technical and flight procedure commission of the TumenEcotrans on the aircraft operation potential. 1996.

The main element of the aerodynamic design of the assessed aicraft is a disk-shaped centerplane of substantial thickness, the central part of which has a tunnel with a liftoff rotor unit that creates a vertical thrust considerably lesser than the all-up weight. Well-developed wing aerodynamic supporting areas and tail pylons with horizontal and double fin vertical empennage are attached to the centerplane. Propulsion engine with thrust fans is located at the rear edge of the centerplane. Take-off and landing gear include wheel-ski undercarriage and inflatable flexible torus to protect air-cushion underneath the centerplane.

The concept development stage is characterized by a large volume of experimental tests of the aerodynamic arrangement in the Moscow Aviation Institute windtunnel and of the life-size aerodynamic model at ground bed and at takeoff and landing mode.

An experimental pilot-controlled aicraft with an airborn weight of 1 ton was used to study the following characteristics and operational procedures:

- impact of a low thrust liftoff rotor on aerodynamic structure characteristics during conversion modes of air-cushion flight and aproaching 3 to 5 meter altitudes;

- effectiveness of an entrance airgrill of the liftoff rotor tunnel;

- operation of propulsion thrust rotors, their interaction with the centerplane and the tail empennage;

- extension and retraction of the landing torus;

- evaluation of wheel-ski undercarriage as a stabilizer during air-cushion mode movement in contact with an airstrip surface;

- stability and controllability during speed roll and approach;

- open tunnel impact on aerodynamic and dynamic characteristics.

Innovative design and technological solutions for main STOL and air-cushion systems and units were found in the process of designing and building of the experimental aircraft. All these facts give good reason to conclude that this concept allows to develop light off-airfield transport aircraft that advantageously combines characteristics of air-cushion undercarriage aircraft and short takeoff and landing aircraft.

There is nothing like the proposed aircraft in the world today and it is protected by patents of the Russian Federation, United States and Germany.

The liftoff powerplant of relatively low thrust does not provide for an aircraft unstick at near zero speeds but considerably enhances lifting capacity of airframe due to lowering pressure on the uppersurface of the wing centersection, aerodynamic load on the entering grill of the centertunnel and the aircushion. Judging by direct tests of pilot-controlled aerodynamic model, the liftoff from a runway comes at speeds corresponding to lift coefficients of 2,5...3 at close to zero angles of attack. During the tests, the above mentioned growth of ascensional force was retained at altitudes envelope of up to 3 meters above surface.

Enhancement of lifting power created by the aircushion underneath the centerframe does not excede 20...30% of flying weight but it realizes the "air grease" effect that considerably lowers aircraft skidding drag at surface contact mode.

Controllability of such aircraft at low speeds is achieved thanks to cooling control units by airstreams of propulsion unit rotors.

Design estimates show that aerodynamic efficiency Kmax is no less than 7...8 and satisfactory flight-technical characteristics can be achieved during flight far above land surface with cutoff lifting rotor and closed tunnel doors.

Direct tests proved the possibility of takeoff and landig at any hard and snow-covered surface that is essential for all-year round operation in the North and the Far East with their climate conditions. Takeoff-landing modes at water surface remain unstudied.

Everything said above allows to conclude that off-airfield aircraft concept worked out by the TumenEcotrans is a promising direction for development of light aircraft with enhanced takeoff-landing characteristics and higher practicability making it possible to operate at unprepared runways.

We consider it possible to develop a draft for light off-airfield aircraft for 5...6 passengers by TumenEcotrans with the assistance of a specialized design aviation bureau. To determine specifications and flight-technical characteristics of such an aircraft futher testing in wind tunnel is necessary.

S.T. Kashafutdinov , Ph.D Deputy director Aviation Institute

S.G.Derishev, Ph.D Chief of NIO-1

Y.N.Temljakov, Ph.D Leading scientific researcher, NIO-1

© "", 2003