The 8217 Wasp is about as simple a helicopter as can be made and still have a functional main rotor. Released in 1998, this little micro model does nothing else. The white flex hoses are somewhat unusual.
Rotor
The rotor's motion is driven by the wheels when the model is pushed through a set of 12 tooth bevel gears. The rubber wheels have good traction, so it is easy to get the rotor to spin even with the 1:1 gear ratio.
By Technicopedia