07-29-2026, 12:13 AM
(Edited 07-29-2026, 05:29 AM by Graeme Smith.)
Well I am at that point totally satisfied with the design, have an experienced aviation company to do the machining and 4 orders, now is the time if anyone has an interest in upgrading to a shaft drive with aviation designed gearboxes and more tail rotor authority, The design uses the standard RW tail rotor blades and connects to the secondary lower shaft, and included in the fkit are 2 reverse pitch horns.
The changes needed to fit the secondary gearbox require the existing Radiator fan to be removed and its shroud and a new shroud replaces it. An electric fan is mounted on the bottom of the radiator, side scoops capture air when in forward flight. The gain in more useable power by deleting the fan saves approx 10hp, the electric fan on the bottom of the radiator consumes approx 1.5 - 2.0hp so you have a net gain of 8hp, BUT when in forward flight the scoops capture the air thus the fan remains off, only in the hover does the fan turn on then it cycles as needed.
So an extra 8hp from the fan swap
and the losses in the belt drive system from Ai amount to...
std Vee belts loose approx 4-6% this consumes about 1.5% per belt so total 0.6 -0.9HP
twist and misalignment 8% - 12% loss 1.2 - 1.8HP loss...... so a loss of 1.8 - 2.7hp in vee belt loses,
Again from Ai a R22 TR gearbox loss is approx 0.15 - 0.3 hp
so our 2 gearboxes should loose approx 0.3hp - 0.6hp a saving of 1.5 - 2.1HP
also our design spins the TR blades a little faster and spins them the opposite way again both add efficiencies which equate to more TR authority and less hp losses.
Thus a saving in total of approx 9HP and a cooling system that works.
Rule of thumb in helicopter performance is 1HP will lift 10lbs,
This from Ai re benefits of anti clockwise rotation
Spinning the tail rotor so that the advancing blade moves up into the main rotor downwash provides two major aerodynamic benefits:
1. Increased Efficiency and Thrust
Higher Relative Airspeed: Because the blade is moving upward against the downward-rushing air of the main rotor, the total velocity of the air over the blade increases significantly.
Greater Anti-Torque Authority: This increased airspeed allows the tail rotor to produce more lift (thrust) with less engine power, granting the pilot superior yaw control.
2. Reduced Vortex Ring State (VRS) Risk
Altered Induced Flow: When a tail rotor blade moves down with the downwash, it operates in highly turbulent, recirculating air that mimics a micro-vortex ring state.
Stable Aerodynamics: Moving up against the downwash pushes the blade into a cleaner, more predictable airflow stream, preventing a sudden and dangerous loss of tail rotor effectiveness (LTE).
The changes needed to fit the secondary gearbox require the existing Radiator fan to be removed and its shroud and a new shroud replaces it. An electric fan is mounted on the bottom of the radiator, side scoops capture air when in forward flight. The gain in more useable power by deleting the fan saves approx 10hp, the electric fan on the bottom of the radiator consumes approx 1.5 - 2.0hp so you have a net gain of 8hp, BUT when in forward flight the scoops capture the air thus the fan remains off, only in the hover does the fan turn on then it cycles as needed.
So an extra 8hp from the fan swap
and the losses in the belt drive system from Ai amount to...
std Vee belts loose approx 4-6% this consumes about 1.5% per belt so total 0.6 -0.9HP
twist and misalignment 8% - 12% loss 1.2 - 1.8HP loss...... so a loss of 1.8 - 2.7hp in vee belt loses,
Again from Ai a R22 TR gearbox loss is approx 0.15 - 0.3 hp
so our 2 gearboxes should loose approx 0.3hp - 0.6hp a saving of 1.5 - 2.1HP
also our design spins the TR blades a little faster and spins them the opposite way again both add efficiencies which equate to more TR authority and less hp losses.
Thus a saving in total of approx 9HP and a cooling system that works.
Rule of thumb in helicopter performance is 1HP will lift 10lbs,
This from Ai re benefits of anti clockwise rotation
Spinning the tail rotor so that the advancing blade moves up into the main rotor downwash provides two major aerodynamic benefits:
1. Increased Efficiency and Thrust
Higher Relative Airspeed: Because the blade is moving upward against the downward-rushing air of the main rotor, the total velocity of the air over the blade increases significantly.
Greater Anti-Torque Authority: This increased airspeed allows the tail rotor to produce more lift (thrust) with less engine power, granting the pilot superior yaw control.
2. Reduced Vortex Ring State (VRS) Risk
Altered Induced Flow: When a tail rotor blade moves down with the downwash, it operates in highly turbulent, recirculating air that mimics a micro-vortex ring state.
Stable Aerodynamics: Moving up against the downwash pushes the blade into a cleaner, more predictable airflow stream, preventing a sudden and dangerous loss of tail rotor effectiveness (LTE).