Abstract: An exhaust control mechanism is provided for use in a model engine system having a source of engine exhaust. The exhaust control mechanism includes first and second tubes and a valve movable in one of the first and second tubes. The first tube includes an upper portion, a lower portion, and a first passage extending through the upper portion and lower portion. The upper portion of the first tube is adapted to couple to a source of engine exhaust. The second tube is coupled to the first tube and the second tube is formed to include a second passage that intersects the first passage formed in the first tube at an intersection region. The valve is movable in one of the first and second tubes to extend into the intersection region.

Abstract: A model rotary wing aircraft is provided that includes a fuselage, a power plant, a main rotor, a tail rotor, and a drive apparatus. The power plant includes a passive cooling system to transfer heat produced by the power plant to the atmosphere. The passive cooling system consumes less than about five percent of the power produced by the power plant. The main rotor is driven by the power plant at a main rotor speed of rotation and the tail rotor is driven by the power plant at a tail rotor speed of rotation. The drive apparatus transfers power from the power plant to the main rotor and tail rotor to rotate the tail rotor at a tail rotor speed of rotation that is about three times greater than the main rotor speed of rotation to minimize the amount of power used by the tail rotor.