DESIGN: ElectrotorPlus ~ Rotor - Hub w/ Spring - General

• The initial idea was to incorporate a spring into the moment rod for the purpose of allowing the MRGA to teeter at a smaller angle then that of the rotorhub at each cyclic. The idea is no good because the purpose of the moment rod is to apply a moment to the MRGA when the rotorhub is teetering not after it has teetered.
• Therefore, consider the use of a damper in lieu of the spring. The damper will only apply the force when the rotorhub is actually flapping; up and down
• These dampers are to be located on the two Moment Rods at one damper per rod.
• Each damper is designed to give a force equal to the torque at the amount of movement for a given degree of teeter of the rotorhub plus the accompanying teeter of the MRGA. This is so the force rods can apply the appropriate torque about the X-axis of the MRGA.
• The use of a damper within the rods means that the two rods do not have to have equal center-to-center distances. This, in turn, means that a teetering ratio of other than one-to-one can be used between the teetering angle of the rotor hub and the teetering angle of the MRGA.
• Note that when the rotor-disk and the MRGA have different teeter angles from each other there will be a cyclical Corollas action between the two

• See Disk

• To minimize the angle differences between the axis of the motor and the axis of the mast, consider giving the mast a forward tilt. The angle of the till should probably be midway between the hover angle and the cruise angle. The aft and forward longitudinal cyclic range can be set to suit the forgoing.

• The hub and its teetering hinge must be stronger than normal to take the hub-spring and MRGA forces.
• Undersling: The undersling will be based upon one specific mean operating weight (say the GW of 550#) irrespective of the final helicopter's configuration of application.

• The blades might have to be stronger in the out-of-plane direction since the hub-spring will resist bending. The offset teetering hub should not require this strengthening.
• See SynchroLite - Rotor.

• DESIGN: Rotor - Disk - Centers, Radii & Moments
• DESIGN: SynchroLite ~ Rotor - Blade - Composite - VR-7b - Centers, Radii & Moments

• Centrifugal effect per blade [F] = 3,949 lb. For the calculations on the SynchroLite (2-blade) see; DESIGN: SynchroLite ~ Rotor ~ Initial Rough Calculations for Rotor Consider adding the SI units etc. on the linked page and just having the link here. IE one data location.
• Rotorhub Speed: [ω_RH] = 600 RRPM = 62.857 rad/sec.
• Teetering frequency [ν_β] = 10 cycles/sec.
• Extended spring length [?]= .
• Force of spring [?] = .
• Undersling: [?] = 1.6" = 0.0991m
• Precone angle: [β_p] = 4º = 0.0698 rad.
• Weight of two blades and grip = 8.25 lb * 2 = 16.5 lb = 7.48 kg.
• Radius to CG of blade = 3.9 ft = 1.189 m
• Force arm radius: [?] = 3" = 0.0762 m

• Teetering angle: [β] Between maximums of -15º to +15º, = -0.262 to +0.262 rad.
• Velocity of teeter [ω_X] Calculated; based upon maximum teeter and Sector.
• Moment of teeter [M_X] Calculated; based upon maximum teeter and Sector.

• To come.

~ From here go to ElectrotorPlus_Gyro.html - Calculations ~

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