Item 0857

DESIGN: UniCopter ~ Control - Flight - Hydraulic - Schematic

Much of this is SynchroLite Item 0408 and must be reworked.

UniCopter related:

The current thinking is to, hopefully, utilize Independent Root & Tip Control. The cyclic input will be directed to the blade tips. The collective, governor and forward velocity inputs will be directed primarily to the blade roots. The hydraulic governor will work in conjunction with a conventional hydraulic system, complete with its own pump.

 

Drawing:

 

Notes Regarding the Above Schematic:
    1. A fourth cylinder-set could be added to the above three and its inclusion will probably negate the need for a central pivot.
    2. A second (redundant) system could be included. The primary system could be rotated 22.5 degrees and the second system located at a 45-degree rotation from the primary system. The dual system could probably utilize smaller components then what would be required for a single system.
    3. The forward velocity wand system (for sensing dissymmetry of lift) should have flow controllers located in the lines so that changes will be gradual and gusts will have no effect.
    4. The two horizontal cylinders in the above drawing might be flipped to the outside so as not to interfere with the pinion gear.

The following drawing should be on a separate page 0407

 The following drawing should be on a separate page 0268

  The 7/16" dia. Cylinder is on drawing Item 0863

Notes:

Cylinder dimensions etc.

Clippard

1000 psi. Maximum pressure.

Force is at maximum pressure

Ratio is port size to cylinder area. This should affect speed?

Max.

Model

Bore Ø

Cyl. Area²"

Rod Ø

Force

Port Area²"

Ratio

Item

H9D-1D

9/16"

.1995

1/4"

200#

.0031

64:1

0863

7DD

7/8"

.5525

1/4"

552#

.0123

45:1 (1/3 faster?)

0268

Hydraulic controls for blade settings (collective & cyclic, Plus tail

Have requested Parker catalog from Cameron at Hyseco.

Have requested Bimba catalog from Andrea at Skeans Engineering.

Have requested Clippard fax from Tom at Wainbee Ltd. 278-4288

Note:- The pitch and yaw controls for rotor and tail could be joined. This would eliminate 2 cylinders at the stick, 1 for nose up/down and 1 for port/starboard. It might be better to leave as is because the current arraignment give some redundancy and safety. Note:- There is no redundancy, yet, for collective.

Collective could be foot controlled, like excelerator in a car.

Forces:

Calculation made from the Indian helicopter drawing show that 1" of cyclic or collective movement, at 17" on arm give an average movement of .125" (approx.) at the swashplate. If the pull or push on the levers is 10 pounds the force on the swashplate rod end is 10 * 1/0.125 = 80 pounds.

The 9/16" diameter cylinder can deliver a maximum of 200 pounds of force. This is at an arm of 3.5" and there are 2 rotors. This means that a maximum pull on the cyclic stick of 100 pounds at a 15" arm.

Yaw control:

If it is decided to locate the hydraulic cylinder(s) at the pedals then consider using flexible hose to the cylinder(s) so that the pedals

1/ can be adjustable for pilots of different heights, &

2/ the foot rest can fold up into the seat when on trailer.

Bleeding of air:

On the ((2 rotors) * (3 cylinders) * (2 ports))- (3 rotor-to-rotor lines) = 9 lines, at their highest point (near swashplate) locate inverted "Ts" with chamber or short vertical tube above and valve above that. One filler pot with valve below can be move from "T" to "T" to bleed air and replace with oil. See sketch in Hydraulic folder.

Viscosity:

What amount of change in the control stick pressures will there be from temperature change in the oil? See page in folder.

Ideas:

Initial Development:

Consider using Clippard H9D-1D, then adding duplicating system for final.

Other Possible Sources of Miniature Hydraulic Cylinders:

American Cylinder Co. ~ Aluminum and Stainless Small Bore Cylinders. http://www.americancylinder.com/

Cylinders & Valves, Inc. http://www.cylval.com/

Chicago Cylinder Corporation

Airoyal Company

Custom Actuators; SMC; & www.control-line.com. See printout of http://www.pneumaticsonline.com/webforum/messages/524.html

Potential Concerns

The ability and ease of initially removing air from all the lines

Change in viscosity and thus changes in required stick forces.

The speed at which control changes can be made, due to the flow rate of the oil.

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Last Revised: August 15, 2003