A051.html

A051

OTHER: SynchroLite ~ Concerns & Tasks

Overview:

A listing of Potential Concerns, Tasks and Thoughts, regarding the SynchroLite.

Potential Concerns:

Alternative Rotors:

2-blade Teetering:

It does not have as much flight-control as I would like. Therefore, develop and test the Electrotor-Plus.

3-blade CVJ w/ Hub Spring:
The weight is almost certainly to be above 254 lbs. The 3-blade rotors will have a slightly smaller rotor disks, however they will require more power.
Breakage in Secondary Reduction:

Make sure that the breakage of any part in one of the two power trains cannot lockup the rotors. The gear calculation, which were based on reverse engineering of the K-Max, do not appear to show provision for the other factors (safety etc.) that my calculations do. What am I not understanding in the gear and bearing (perhaps whole power-train) design process?

Oscillation between Rotors:

The long masts may allow a dynamic torsional oscillation to take place between the two rotors. If the is no damping, this may excite to a critical level.

Idea (2): By changing the wall thickness of the masts, make sure that the oscillation frequency of the rotor-rotor connection is as far away from RRPM as possible. This may not work; particularly during autorotation.

Another crazy idea: Use composite, perhaps with varying diameter.

Perhaps the profile drag of the rotors, which varies with speed, may dampen any desire to oscillate.

Run-0n Supports for Emergency Landings:

A number of people have expressed the need to provide for this. See:- DESIGN: Landing Gear

Disk size:

Could start off with long blades and highest gearing, then later reduce the blade lengths and reduce the belt/pulley reduction. This will give better lift &/or less load on engines (re cooling etc).

Vibration: Rotor - Rotor Interaction

The action of the blades as they enter and leave the downwash from the blades of the other rotor.

Vibration: Rotor - Appendage

The blades in the two rotors will pass over the tail 6 * rotor RPM (approximately 6 * 600 / 60 = 60 times a second). If the downwashes have any rotation to them (CW & CCW) then this may possibly rock the tail in each direction 30 times per second. The bracing from the top of the seat should be such a length so as to set up a frequency in the tail that counters the blade wash or the wrap of the plies in the composite boom offset this action. See DESIGN: Fuselage - Tail - Airflow from Downwash

Forward Speed Limitation

What limits the speed of forward flight with the synchropter? DRAG? Could it be that the amount of teetering must be limited so that the blades will not hit each other and this limited teetering limits the amount of forward longitudinal cyclic. If this is the case could the longitudinal cyclic be augmented by controllable pitch on the stabilizer?

Cooling of engine:

Safety of bystanders:

The blade tips are relatively low, especially at the sides. For partial solutions see: B196 ~ Personnel on Ground

Ground Clearance:

The clearance between blade tips and the ground, particularly at the sides. See web page 0775.

Torque ~ Pitch Cross-coupling:

A change of torque in the intermeshing configuration causes a change in pitch.

See: 0842. OTHER: Flight Dynamics - General Cross-Coupling - Torque ~ Pitch

Concerns About the Large Stagger Configuration: See drawing 0472_Wide_Stagger.dc

The ascetics due to the large stagger of the rotors.

The indirect path of the flight control rods (angle and (through the final gear?))

Large sheave, up at rotors.

Yaw control

Consider making power-train, rotors and perhaps engine as one package [like Dragonfly]

Thoughts:

Look into 'Scientific Research & Experimental Development' tax credits?

Would this project be of interest to a University or their students?

Contact Bombardier? They are into aerospace and recreational vehicles.

Consider usage of the drive train in Remotely Piloted Vehicle.

Testing of Prototype:

The intent is to;

Build one hub.
Build three very cheap and simple substitute blades.
Build a test stand.
Test it stationary and then on the back of a pickup truck.

Build the flight controls.
Test it stationary and then on the back of a pickup truck.

Build the proper blades.
Test it stationary and then on the back of a pickup truck.

Build a cheap frame and gyro controlled electric tail rotor.
Acquire vibration and stress analysis equipment.
Add a ballistic parachute.
Test the "single rotor' as a 325 lb RV.

Assuming everything is good at each phase;
Build the other rotor plus the complete final power train.
Build a simple fuselage.
Test remotely and piloted.

Build the final fuselage.
Test and improve, Test and improve. Test and .........

Tasks (to do):

Keep weight down. For more ideas see: Weight & Balance.

Keep the cost down.

Devise means of isolating engine rotational shock from power train. See A008

Finish design and detailing of drive train.

Reassess vibration caused by interaction of rotors. Vibration Analysis - Rotor Induced

Consider blade-blade interaction in respect to cross-coupling.

Develop and built prototype of Rotor Governor [item 0831]

Include canopy in design ~ structural, weight and balance considerations.

High fuel tank and Canopy layout.

Adjustable pedals, adjustable seat or seat back/bottom insert etc. for variable pilot height/weight.

Power Train vs. Frame re: Interaction of control rods and belts.

Empennage: Decide on Ruddervator or Stabilator and then finish design, using Bell 206 uniball

Review rotor - rotor clearances.

Blade-blade clearance in yaw.
Blade to hub clearance.

Swash plate design to be finished.

Detail Run-on supports ????.

Evaluate pros & cons of using twist. See: [B188] and taper and drooped tip [0740] .

Design and start building composite blades.

Opposed Lateral Cyclic.

Potential Future Safety Features:

Electronics - Sensors, computers and actuators (I.E. input, processing & output) will play major roll in future. FADEC (Full Authority Digital Engine Control), HUMS (Health and Usage Monitoring), Digipod

Same Page Different Craft: ~ UniCopter ~ Nemesis

Considerations as to which Helicopter to Build;

OTHER: Miscellaneous - SynchroLite vs. UniCopter

Last Revised: August 15, 2008