UniCopter_RotorBrake

UniCopter ~ Power Train - Rotor Brake

Overview:

One of the reasons for the inclusion of a rotor brake is that if remote control testing is to be done. On the occurrence of a potentially craft damaging problem, perhaps the rotors could be stopped and a parachute deployed.

The major reason is the potential danger to personnel because of the low blade elevation at the sides.

Notes:

Consider locating brake on x-over shaft on opposite side to sheave, on the arraignment where the engine is mounted crosswise in the fuselage. If the brake is inside a single fully enclosed power train, would the brake-lining contaminate the oil.

If the transmission has a PTO, could the brake be external and connected to (a stronger than normal) PTO?

If there is a centrifugal clutch in the power train, can it some how be used as a brake as well?

See comment on rotor brake location on DESIGN: UniCopter ~ Power Train - Overrunning Clutch

Make sure that the brake cannot be applied while the soft-start clutch is engaged. Ref. Kellett

Wild Idea: Make the oil pump (used for cooling or for external application) super strong, then to brake the rotors reduce the orifice on the pressurized side of the pump.

E-mail to PC re Cattle Mustering.

The blade tip elevation will be a problem with the Dragonfly and the UniCopter.

The Brantly shows an elevation of 2.11 m from the top of the rotor to the ground. The center of its hub to the ground looks like 2.02 m. The offset rotor on the Dragonfly and the 'absolutely' rigid rotor on the UniCopter require a shorter coupling between the rotor and the craft's CG then that required for a teetering rotor such as the Robinson's. The center of the hub to the ground on the Dragonfly mockup is 1.78 m and the center of hub to the ground on the UniCopter mockup is 1.75 m. In addition, the blade tips will be even lower at the sides of the crafts.

A larger UniCopter, with 4 to 7 seats would not have this problem, but a small 1 or 2 seat version will. Even the single seat teetering-rotor Helicycle http://www.helicycle.com/ has this problem. When Schramm gets out of his helicopter to engage the rotor, he said that he drags the knuckles of one hand on the ground to be assured that his head is not in the path of the blades.

Perhaps rotor disengagement and a fast acting rugged rotor-brake may overcome this problem. The UniCopter will be able to handle a fast RRPM deceleration because its design mandates a very rugged rotor and power train. The Dragonfly's drive train must be reasonably stronger than those on single rotorcraft, therefore a couple more pounds of strengthening to handle a reasonably fast rotor-brake should not be a problem.

The time required to rebuild the RRPM is unrelated to how fast the RRPM can be reduced.

Will the elevation problem eliminate one or both of the helicopters from mustering?

Working Papers:

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Last Revised: October 2, 2004