AT CAD Team/AT freight aircraft
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This article is about the AT freight aircraft. The AT freight aircraft is low-cost, high-efficient cargo airplane. It is hence on focused on endurance, and not speed nor agility. It is based on the Waco CG4A Hadrian, yet has been modified significantly. Ie to reduce weight/complexity, the number of ribs, fuselage beams, ... have been reduced, engines/propellers were added, biplane wings have been foreseen, the loading method is changed and the wing profile used is the Clark YH (see http://www.worldofkrauss.com/foils/175 ).
[edit] Versions
2 versions of the aircraft can be made: a manned and unmanned version. With the unmanned version, the control stand is outside of the aircraft rather than in the tail, and the ailerons, flaps, elevators, rudder are then controlled wirelessly (by means of an antenna). Radio repeaters could be placed along the path of the regular flight route, hence allowing radio control over (any) distance. The ailerons and flaps are controlled in both aircraft versions by means of a electric motor. The rudder and elevators are controlled manually using a wire in the manned version, in the unmanned version, they can be controlled by solenoids controlling the wires.
In both versions:
- the loading of the cargo is done via the nose. The nose (together with the front propeller) is removable. The pilot (with the manned version) has a seperate hatch to enter and leave the aircraft (ie in the event of an emergency).
- the landing gear can be lowered/heightened by means of a solenoid system
[edit] Propeller, engines and fuel tank
The aircraft has 3 propellers, two of which (in the wing) are powered by a quasiturbine. The front propeller (on the fuselage) is powered by a (Beta-type) Stirling motor. The yellow round box in the model is an oil resrvoir and transfers the oil (heated by the quasiturbine) to the hot side of the Stirling engine, hence increasing the energy efficiency (the entire assembly is 70% efficient). 2 fuel tanks are present, one on the top wing, the other on the bottom wing. The fuel is only drained from the top tank. However, when the fuel level drops to below a certain point, it is refilled using fuel from the bottom tank (this is done automatically, using a fuel pump). A special turbocompressor is also present, it is cooled using only oil, the heated oil is also used by the Stirling motor. The entire assembly would need to have about 400 HP.
The fuel used in the aircraft is ethanol. Although this is not a emissionless fuel on itself, it can be made emissionless if the ethanol comes from a vegetable origin (preferably from wood, ie cellulosic ethanol). No N20 was foreseen as this significantly increases the complexity and space requirements.
