The Reducer - Compact Radial Engines MZ201 Instruction And Maintenance Manual

Function of the speed reducer
Two-stroke engines are designed in such a way as to generate full power at a high number of revs,
namely, 5000 rpm or higher. At these speeds, the performance of the propeller would be unsatisfactory on
account of its small diameter and would produce an unacceptable amount of aerodynamic noise on account
of the speed of rotation.
The only way of reducing the noise and boosting performance is to fit a speed reducer between the
engine and the propeller.
Choosing the right reducer.
In view of its simplicity, weight and manufacturing costs, we recommend fitting a belt-driven
reducer. It also has the additional advantage of being quieter than a model with metal gearing.
Various types of belt-driven reducers are available. The choice depends on the weight of the reduction unit,
the external dimensions and the power to be transmitted. Belts may be Polyflex or Poly V.
Adjusting the belt tension.
d
When the MZ201 leaves the factory, it is already fitted with a speed reducer and the belt tension is adjusted
correctly. However, during the first few minutes of use, the belt "settles" into position and loosens slightly.
It is therefore essential to re-adjust the tension after the first half an hour of operation when the belts are
new and as necessary to comply with the above drawing.
Furthermore, during each preliminary inspection before taking flight, we recommend checking the tension
and condition of the belt. The drawing above shows how to regulate the tension.

THE REDUCER

F = 5 kg
The belt should not move
by more than 2 mm if a
pressure of 5 kg is
applied.
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