raven-rotor
Newbie
Last week was lucky enough to have a Kaman K-Max helicopter land here at our new R & D facility at the airport in Taos, NM. Got to talk with the pilot who was on his way to pick up a downed helicopter with the 6000lb. pick-up point on the K-Max. Watching the intermeshed rotors picking up speed in the morning sunlight was impressive as well as the take off performance at our 7200 ft. field elevation.
Restimulated a question that had come up for me a few years back as to why no one has developed a simple intermeshed twin rotor gyro using off the shelf, inexpensive teetering two bladed rotors. One of the things I remember clearly from the Windryder development days was the limitation of the 2 blade teetering rotor diameter to the 30-31 ft. range. This has always put a very restrictive cap on the useful payload of the gyro's of today. Would not a simple intermeshed permanently powered rotor system allow for increased payload, higher top speed, shorter take-off roll, etc.
I am not a rotorhead or blade designer by background but have successfully tackled some very tricky power transmission problems in my work with converting the Geo/Suzuki auto engines for aircraft. Preliminary design calculations for a transmission to reduce power from the main engine and split it to each rotor pencil in at a weight of less than 60-70 lbs. from rotor towers to CVT transmission input from main engine. This includes a conservative 25HP input to the rotors and redundancy in key components of the intermeshed system. Weight penalty subtracting the original single rotorhead and prerotator would be less than an additional 40 lbs. not counting the extra hub bar and blades.
'Kaman Gyro' would have to be a pusher to simplify engine placement for both prop and power to rotors. Full flying tail outside the rotors arc would take care of pitch and yaw. My questions for the rotorcraft experts frequenting this site is how to handle roll axis of the the intermeshed system in a simple way. Can pivot the complete rotor drive system at a point anywhere along the axis between and just below the rotor blade intersect (obviously my first choice for simplicity) or can, with the drive system I've designed, tilt each rotorhead independently but linked in the pitch axis. This would be a second choice as it increases the rotorhead seperation/incline out from the aircraft centerline to make sure the already teetering blades do not intersect.
What are the pro/cons of intermeshed rotors on a utility gyro? What would be the most optimal phasing of the two rotors with each other? Would this simple control of the roll axis have any undesirable flight results?
After looking into both a permanently powered rotor system as well as jump takeoff capability for gyro's, I have come to the conclusion IMHO that jump take-off will most likely never be a a mainstream option for the average gyro pilot. The increased cost, risk, critical flight envelope parameters, and pilot skill required are more than what is gained back in real world flight performance for a craft that still can't hover.
Thanks in advance for the feedback.
Jeron Smith
Raven Rotorcraft
Boulder, CO
303-440-6234
Restimulated a question that had come up for me a few years back as to why no one has developed a simple intermeshed twin rotor gyro using off the shelf, inexpensive teetering two bladed rotors. One of the things I remember clearly from the Windryder development days was the limitation of the 2 blade teetering rotor diameter to the 30-31 ft. range. This has always put a very restrictive cap on the useful payload of the gyro's of today. Would not a simple intermeshed permanently powered rotor system allow for increased payload, higher top speed, shorter take-off roll, etc.
I am not a rotorhead or blade designer by background but have successfully tackled some very tricky power transmission problems in my work with converting the Geo/Suzuki auto engines for aircraft. Preliminary design calculations for a transmission to reduce power from the main engine and split it to each rotor pencil in at a weight of less than 60-70 lbs. from rotor towers to CVT transmission input from main engine. This includes a conservative 25HP input to the rotors and redundancy in key components of the intermeshed system. Weight penalty subtracting the original single rotorhead and prerotator would be less than an additional 40 lbs. not counting the extra hub bar and blades.
'Kaman Gyro' would have to be a pusher to simplify engine placement for both prop and power to rotors. Full flying tail outside the rotors arc would take care of pitch and yaw. My questions for the rotorcraft experts frequenting this site is how to handle roll axis of the the intermeshed system in a simple way. Can pivot the complete rotor drive system at a point anywhere along the axis between and just below the rotor blade intersect (obviously my first choice for simplicity) or can, with the drive system I've designed, tilt each rotorhead independently but linked in the pitch axis. This would be a second choice as it increases the rotorhead seperation/incline out from the aircraft centerline to make sure the already teetering blades do not intersect.
What are the pro/cons of intermeshed rotors on a utility gyro? What would be the most optimal phasing of the two rotors with each other? Would this simple control of the roll axis have any undesirable flight results?
After looking into both a permanently powered rotor system as well as jump takeoff capability for gyro's, I have come to the conclusion IMHO that jump take-off will most likely never be a a mainstream option for the average gyro pilot. The increased cost, risk, critical flight envelope parameters, and pilot skill required are more than what is gained back in real world flight performance for a craft that still can't hover.
Thanks in advance for the feedback.
Jeron Smith
Raven Rotorcraft
Boulder, CO
303-440-6234
