1719

Item 1719

OTHER: Aircraft - Gyro/Heli - UniCopter-Lite - Single Rotor - All Electric

Overview:

A theoretical and preliminary design for the development of an all electric recreational hybrid helicopter/gyrocopter (UniCopter).

The twin propulsor idea MIGHT be successful, but the rotatable single propulsor idea will require a rotor motor of > 30 hp and a propulsor motor of > 30 hp.

For alternative idea see OTHER: Aircraft - Gyro/Heli - UniCopter-Lite - Intermeshing - All Electric

Disadvantages compared to 'Single Rotor' above:

Needs larger motors for the single rotor and the propulsor. Can do ~ design and build them: Perhaps have them identical except for axial length and/or wiring and/or phase count etc.

Current Tasks and Concerns:

Tasks:

To find or build a motor for the rotor that produces 30 - 40 HP. Direct drive or planetary reduction.

Concerns:

The propeller might have to be two position propeller system, or more advanced system to offset hovering rotor torque and provide frorward flight at a respectable speed.

Objectives:

Stage 1:

Partially powered main rotor. Note that increasing the mechanical power to the motor will probably require a decrease in the longitudinal dimension between the transverse pitch pivot and the teetering pivot (center of lift).
Side-by-Side propellers;

Independent variable thrust to counter the torque from the powered rotor.
Rotatebly downward to assist the rotor during vertical take-off and landings.

Stage 2:

Fully powered main rotor,
Single pusher propeller mounted on tail-boom, which is rotatable about a vertical axis so as to counter the torque from the main rotor during vertical and transitional flight.

Drawings:

Alternative A: Modified SynchroLite

Alternative B: Modified Gyrobee

Overall Conceptual Outline:

The rotor is powered by an electric motor and a planetary reducer. Electrotor-Simplex, perhaps with some modifications or with an Electrotor-SloMo

The two propellers are direct driven from their independent motors.

To counteract the torque from the main rotor the starboard propeller is driven at a higher RPM than the port propeller

Tilt propellers downward to assist with take off.

With CCW turning rotor, the downward facing starboard propeller is tipped down by less than 90˚ and the port propeller is tipped down more than 90˚ so that they offset the torque from the rotor.

Do calculations for twin propellers and downward thrust

Do calculations for 45-degree rotating tail rotor

Features:

Propellers:

Both propellers have fixed pitches. Or, both propellers have 2- position pitch
The thrust of both propellers is determined by their rpm.
One or both may be driven at over 100% for a few seconds at specific times.

Prerotation: Alternative

The Starboard propeller is drive at a speed that contributes to resisting the torque that is generated in bringing the rotor up to the desired rpm
The Port propeller is driven in reverse at a lower speed. The lower speed of this propeller also contributes to countering the rotor's torque. However, it provides less thrust because its airfoils are rotating with the 'trailing' edges leading at this time.

Drawing of Rotor Assembly;

for Stage 1:

This is currently the Electrotor-Simplex. It will be simplified for this application.

Concern ~ Does this motor produce enough torque to initiate the rotation of the rotor?? Hand start??

For a larger view click on the above drawing, then click on the mouse (magnifying glass) for a clearer view.

Sketches of the sub-assemblies, plus a discussion on Rotary Wing Forum.

for Stage 2:

This is to be a modified version of the Electrotor-SloMo.

Overview of Propeller Assemblies:

Overview of Peripheral Assemblies:

Misc:

Motor:

Plettenberg - Predator37 ~ Paramotoring; http://www.electricppg.com/ are using a Predator motor and belt drive for one of their designs (France).

Simplex ~ Power Train - Motor

Technical Information on large model fixed wing driven by Predator 30:

http://www.aoe.vt.edu/design/intl0708/documents/FINAL.pdf

http://www.rcgroups.com/forums/showthread.php?t=776635

http://www.plettenberg-motoren.com/UK/erfolge.htm

For information on Gyrobee;

DESIGN: Electrotor-Simplex ~ Rotor - Hub - Gyrobee Information
OTHER: Helicopter - Inside - Single Rotor - All Electric Backpack (PAV) (UAV)

Assuming that the power required to hover is 30hp this is 30

Power Splitting between Rotors and Propellers:

General Gyrocopter Data from Homebuilt Rotorcraft:

If ship's gross weight is 650 lb then there must be 325 pounds of static thrust.

An efficient prop will develop around 5 pounds of thrust per horsepower.

It will take at least 65 HP to develop 325 pounds of thrust.

Torque Calculations based on a 300-lb Ultralight heli/gyro operated by remote control for testing. 50% of power to Rotors and 50% of power to Prop:

Rotor [Torque x RPM] = Prop [Torque x RPM]

Motors are maximum of 19 HP each.

The rotor speed is based on 25 ft diameter, turning at 390 RPM for a tip speed of 512 fps (M 0.46)

Assume; operating Prop RPM is 2400

Horsepower [HP] * 5250 = Torque [Q] x RPM [RPM]

Therefor Torque [Q] = (Horsepower [HP] * 5250) / RPM [RPM]

Rotor Lift: [Q_R] = (Horsepower [HP_R] * 5250) / RPM [RPM_R] = (15 * 5250) / 600 = 202 lb-ft

At 10 lb of thrust per HP the lift is 202 lbs.

Propeller Lift; [Q_P] = (Horsepower [HP_P] * 5250) / RPM [RPM_P] = (15 * 5250) / 2400 = 33 lb-ft

At 5 lb of thrust per HP and the motor delivering 15 HP the propulsion is 75 lbs. And, since 1 lb of static thrust will lift 2 lb GW the lift is 150 lbs.

The theoretical lift is 202 + 150 = 352 lbs.

The lift might be even better than this allow for a very light persons to fly the craft.

Plus, a very short duration of overpowering the motors might allow this light person to have vertical take off.

Whatever, the rotors etc will be oversized so as to have the ability to accommodate more powerful motors in the near future.

Offsetting Rotor Torque:

The use of two Plettenberg will be too little for vertical takeoff and may be too little for running takeoff. However the idea may be valid when larger motors become available.

Potential Improvements to the above:

Rotate boom and tail feathers.

Shorten boom

Note that port side of propeller disk may create a low preasure on the port side of the fuselage and this would be good.

Rotate 60˚ (15˚ more than shown 45˚)

Move the propeller further aft.

Make legs slightly longer.

Have rotor and propeller SloMo motors identical except for Hz or wiring of motors (so that PRPM < RRPM)

The torque of the rotor (profile and induced drag) must be offset by the propeller or vertical fin(s) or (???).

At zero forward velocity, all the drag is generated by the rotor (profile & induced drag).
At low, accelerating forward velocity, all the drag is generated by the rotor (profile and induced drag) but some of the propeller's thrust must be devoted to accelerating the helicopter mass, which is on the for-aft centerline.
At high forward velocity, most of the drag is from the fuselage (parasite drag) and it is inline with the fuselage. Some drag is still generated by the rotor (profile and induced drag) plus some drag from the H-force.

The propellers thrust must offset the thrust of the rotor. This thrust must be located approximately 2-1/2 feet to the right of the centerline during hover and move toward the centerline as the forward speed increases. Therefore, consider 2 propellers, one on each side of the mast. The starboard propeller has a fixed pitch and the port propeller to have a variable pitch. This variable pitch would not move to a feathered position but to a flat-on position or a reverse thrust position during hover.

Prop Pitch Control:

Prop pitch control is required to offset the yaw caused by rotor torque.

The values in next two lines come from the Power Splitting segment above:

The prop thrust is (1/2 of 500) = 250 pounds of static thrust.

The rotor torque is 656.25 lb-ft.

At the start of ground roll, when taking off, the propeller is required to

Offset the rotor torque of 656.25 lb-ft.
Direct all of its thrust backward, to build up forward speed as quickly as possible.

Therefor the length of the moment arm of the propeller will be 656.25 / 250 = 2.625 feet. If the center of thrust on the propeller blade is at 80% of its radius, then the propeller must have a 6.56 ft. diameter. Having a movable rudder (or twin movable rudders) linked in with the propeller pitch yaw control can reduce this diameter to a reasonable size.

Drag and Forward Velocity:

The drag (profile and parasite) will always be greater on the right hand side of the craft therefor in straight flight the starboard prop will be set at a slightly greater pitch then the port prop.

Overrunning Clutch:

A overrunning clutch will be required on the rotor mast to allow the rotors to continue turning in the event of a disabled drive. The rotor governor will automatically set the collective pitch of the rotors to the autorotative setting

Concerns:

Protection From and To the Propellers: Place a lightweight open framing around the rotor just like on paramotoring (powered paragliding),

How is yaw handled in hover and vertical flight? Rotation of Propeller about the vertical axis?

Bill of Material 1719 ~ Not yet done for this craft, nor final design decided.

Primary Grouping:

Concerns & Tasks

DESIGN, MAKE & BUY:

Rotor Assembly: Not yet modified for this concept

Sketches of the sub-assemblies, plus a discussion on Rotary Wing Forum.

Propeller Assemblies: Not yet modified for this concept

Propellers

Peripheral Assemblies: Not yet modified for this concept

Single and Tail:

Power Storage:

Electrotor-SloMo ~ AeroVantage ~ 1/4 Scale UniCopter Electrical Storage ~ AeroVantage - Power Storage - Scale Model ~ UniCopter ~ OTHER: Electrical - Power Storage

Method of Operation:

Running Takeoff:

Lock wheels?
Turn starboard propeller at high thrust.
Turn port propeller at low level reverse thrust
Take rotor up to appropriate RPM.
Release wheel brakes.
Change port propeller from reverse thrust to forward thrust.

Note that the starboard propeller will always be delivering mor thrust than the starboard propeller will while the rotor is being partially powered.

Vertical Takeoff:

Point the propellers downward so that they can assist with the lift.

Running Landing:

Vertical Landing:

Notes:

Vertical takeoff.

Faster forward speed then a gyrocopter and helicopter, because of its compound configuration.

Eliminate possible loss of operating RRPM.

Outside Information:

Look up patent of tillable single rotor.

Initially displayed: April 26, 2009 ~ Latest revision, July 31, 2009