Governor

SynchroLite ~ Control - Flight - Governor

Overview:

The governor controls the rotor speed (RRPM).

There are essentially two types of governors;

The Engine governor; which controls engine power, and thereby the inertia going into the rotor disk.
The Rotor governor; which controls collective blade pitch, an thereby the inertia being removed from the rotor disk.

Reason for Governor:

Robinson R22:

A review of NTSB accident briefs clearly demonstrates that wire strikes are the primary cause of fatal accidents, followed by blade stall due to low RPM and continued flight into IMC. In addition, it has been stated that the inclusion of a governor has reduced the rate of accidents.

Mini 500:

Most of the accidents were attributed to pilots entering into a low rotor RPM condition and not recovering properly. ~ from an article in Homebuilt Rotorcraft written by Laura Fetters.

Autorotation:

At a fixed collective setting, the rotor's rpm will vary depending upon density altitude and gross weight [Source ~ CC p.78-79]. A rotor governor will assure that a fixed RRPM (Nr) is maintained.

But, why then "Dr. Hohenemser had planned a barometrically controlled governor [for the FL-282] to take care of large ranges of altitude, but it was never constructed, as the ceiling of the present machines was not sufficiently high to justify it."

Preamble:

State:	Transformation:
Energy is stored in the fuel tank: as a chemical in a liquid form. (BTUs)
	The engine converts the liquid energy into mechanical kinetic energy and the power train passes this power to the rotor disk. The throttle grip on the collective is the pilot's means of controlling the rate of conversion.
Energy is stored in the rotating rotor disk as mechanical inertia. (1/2 x Moment of inertia x Angular velocity^2)
	The rotor blades convert the mechanical energy into an aerodynamic force. The lever arm on the collective is the pilot's means of controlling the rate of conversion.
Aerodynamic lift (thrust)

A correlator may be incorporated to partially synchronize the two transformation functions.

A governor may be incorporated to automatically controls one of these two transformations, It responses is controlled by the variance of the energy stored in the rotor disk.

Rotor Disk: The mass of the rotor disk cannot vary. The rpm of the rotor disk can vary. This variance of rpm should be minimal, under normal operating conditions. The pilot or governor controls this variance.

General:

The function of a governor is to maintain a predetermined the rotor speed [RRPM] [Ω].

The pilot has manual control or overriding control over the Throttle [P] and the Collective [θ₀].

The three (or maybe 4) methods of governing are;

Engine governor: The collective [θ₀] is manually controlled. The throttle [P] is governed to maintain engine speed, which in turn maintains rotor speed [Ω]. The throttle has manual override. This is the most common method. This method governs the energy going into the rotor disk.

Rotor governor:

by RRPM Sensor: The throttle [P] is manually controlled. The collective [θ₀] is governed to maintain rotor speed [Ω]. The collective has manual override. This method gives automatic autorotation. See [MDD p.112]. This method governs the energy coming out of the rotor disk.

by Cone-Pitch Coupling: - The collective pitch [θ₀] is partially 'governed' by the coning angle [a₀]. Ref. the AH-1 Cobra. For additional information on pitch-cone coupling see Chuck Beaty's notes on Groen. Might the application of collective cause an increase in the coning angle, which in turn will cause the cone-pitch coupling to reduce the collective pitch?

Combined Torque and Cone-Pitch Governor: Idea only - see: - OTHER: Miscellaneous - Thoughtless Ideas - Auto-Collective Rotor

Working Papers:

DESIGN:

B096

MAKE:

B241

BUY:

B138

Items:

DESIGN:

	Name	Item
	Control - Power Train - Governor - Rotor Type - Electronic & General	0825
►	Control - Power Train - Governor - Rotor Type - Hydraulic Schematic	0831
	OTHER: Miscellaneous - Thoughtless Ideas - Constant Speed Rotor	0786
	OTHER: Miscellaneous - Thoughtless Ideas - Auto-Collective Rotor	0575

MAKE:

	Name	Item
►	Control - Power Train - Governor - Rotor Type - Hydraulic - Assembly	0833
	Control - Power Train - Governor - Engine Type - Zeus - Assembly	0570

BUY: Possible sources

	Name	Item
	Control - Power Train - Governor - Engine Type - Zeus	0345
	Control - Power Train - Governor - Engine Type - Hoof
	Control - Power Train - Governor - Engine Type - Woodward
	Control - Power Train - Governor - Engine Type - STABL-1
	Control - Power Train - Governor - Engine Type - The Governor (RC)
	Control - Power Train - Governor - Engine Type - Eric Cymbaliuk
	Control - Power Train - Governor - Engine Type - RotorWay?
	Control - Power Train - Governor - Engine Type - Robinson R22	1118

Related Page at This Sites:

DESIGN: SynchroLite ~ Rotor - Disk - Autorotation

See William Hunt's, of Sikorsky, idea for an autocollective; [Source ~ HP p.194-196]

Same Page ~ Different Craft: ~ Dragonfly ~ UniCopter

Last Revised: December 25, 2005