THE ELECTRIC ONES This type of helicopters functions with electric energy. If you choose this style of helicopters, you will have to buy either a fast and high-performance charger or many extra / spare batteries. You have to know that the flying autonomy of electric engines is half less important than the one of heat engines. This sort of aircraft is heavier than the heat-engine ones but it is almost noiseless and it remains clean even after a flight.

THE HEAT-ENGINE ONES This type of helicopters is equipped with an engine of 8 to 10 ccs - the traditional models of this engine functioning with methanol. Petrol engines (having the same capacity) have begun to appear for two years. Heat engines are generally equipped with a more voluminous cylinder head in order to improve the cooling operation. This type of helicopters is noisier than its electric counterpart. Oily deposits dirty the aircraft : the cleaning part takes quite a long time after each flight. Despite some drawbacks, the heat-engine models remain lighter and more vivacious than the electric ones.

Some information about Radio-Controlled helicopters :

• The altitude record of 1992 is held by a man from Toulouse (South of France) : 2950 meters.
• The speed varies from 80 to 100 km/h depending on the equipment.
• At the very end of the blades, the speed exceeds 400 km/h.
• The first back flight took place in 1979.

• THE JUNIOR 50 II (heat-engine model)
  • Category : beginners, training sessions.
  • Manufacturer : Robbe / Schulter.
  • Diameter of the back rotor : 225 mm.
  • Number of blades : 2.
  • Rotor diameter : 1180 mm.
  • Fuselage length : 1150 mm.
  • Height : 400 mm.
  • Weight : 3500 gr.
  • The review RCM has tried this aircraft in its n° 132 and n° 133.

	This picture was taken in 1995 at Montbrun Les Bains (Drome, France). The aircraft is a Junior 50 II : it is equipped with a MAGNUM PRO SE 46 (7,5 cm3) engine.
The hoop improves the stability of the aircraft whn landing. In case of a non-traditional landing, the hoop may avoid to break the blades. However, this device does not guarantee an absolute protection.

CALCULATION OF AN ENGINE CAPACITY
The capacity (in cm3) is rarely indicated on the engine. The figures which are generally found on engines are expressed in cubic inches. In order to find the corresponding figures in cm3, you must divide the cubic inch capacity by 6,1.