High speed AH-64 : Boeing proposing Pusher Prop on tail
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High speed AH-64 : Boeing proposing Pusher Prop on tail
Shades of AH-65 Cheyenne? Boeing looking at high speed AH-64 with pusher prop.
http://www.thedrive.com/the-war-zone/24503/boeing-is-developing-a-new-high-speed-apache-gunship-with-a-pusher-prop-on-its-tail
I recall reading that at maximum speed, the Cheyenne was using all but 300 hp of its power - about 3600 hp - through the prop, with a max speed of 244 mph. An A-1, about the same size, was one-third faster on three-fourths the power. Advancing-blade drag is a 
. And it's not just the speed, it's the range/endurance.
. And it's not just the speed, it's the range/endurance.
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AFAIK, it was tip-jet propulsion that Wittgenstein got a patent on, intended as a way of driving a propeller, rather than the use of a propeller for propulsion of a helicopter. Still, aeronautical engineering isn't the normal entry route to a career in philosophy.
As i recall on the piasecki 16, a big rudder in the tail fan
The 16H-1 combines the efficient vertical lift of the helicopter rotor with the higher speed and maneuverability advantages of fixed wing aircraft. This was achieved by adding a wing to unload the rotor in forward flight, and utilizing a tail-mounted ducted propeller, "Ring-Tail", to provide forward thrust during high speed operation. Thus, the main rotor was unloaded as speed increased, and rotor blade stall and vibration problems of the conventional helicopter were greatly reduce. Directional and anti-torque control during hover and slow flight was accomplished by the ring-tail with deflecting vertical (rudder) vanes in the exit section.
The 16H-1 combines the efficient vertical lift of the helicopter rotor with the higher speed and maneuverability advantages of fixed wing aircraft. This was achieved by adding a wing to unload the rotor in forward flight, and utilizing a tail-mounted ducted propeller, "Ring-Tail", to provide forward thrust during high speed operation. Thus, the main rotor was unloaded as speed increased, and rotor blade stall and vibration problems of the conventional helicopter were greatly reduce. Directional and anti-torque control during hover and slow flight was accomplished by the ring-tail with deflecting vertical (rudder) vanes in the exit section.
Last edited by rigpiggy; 30th Oct 2018 at 05:01. Reason: Piasecki.com
The high-speed Apache that is the subject of this thread does retain the tail rotor. The Boeing design that is currently being tested is very different from the Piasecki design pictured above. I would post an image, but am not paying a subscription to Photo Bucket for the privilege....
You can link to an online image using its URL, so need need to pay anything to Photobucket. (Other image hosting solutions, which are free, also available e.g. tinypic).
Other stuff deleted - Sorry! I fell into the trap of assuming the image in the first post related to the story, and didn't read your post carefully enough.
Other stuff deleted - Sorry! I fell into the trap of assuming the image in the first post related to the story, and didn't read your post carefully enough.
Last edited by hoodie; 30th Oct 2018 at 14:19. Reason: Read post more carefully.
The URL of the high-rez is behind the Jane's paywall, so unless you have a subscription it's not going to work. There is a low-rez version here https://www.janes.com/article/84079/...apache-concept
Image is of a briefing slide shown at the Vertical Flight Society’s Helicopter Military Operations Technology (HELMOT) conference. To describe it, the pusher propeller is not shrouded but is instead open in a similar fashion to the SB>1 Defiant. The tail rotor is positioned on the end of the horizontal stabilizer, and so sits clear of the pusher-propeller.
Image is of a briefing slide shown at the Vertical Flight Society’s Helicopter Military Operations Technology (HELMOT) conference. To describe it, the pusher propeller is not shrouded but is instead open in a similar fashion to the SB>1 Defiant. The tail rotor is positioned on the end of the horizontal stabilizer, and so sits clear of the pusher-propeller.
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No, according to the link below (mentioned up in the Rotorheads forum here), it's "a tail rotor that could articulate 90 degrees in order to provide forward thrust during level flight." So you'd get a transition back and forth from standard TR anti-torque to pusher prop:
Boeing Is Testing A New High-Speed Derivative Of Its Apache Gunship - The Drive
Interesting idea if that's what it is, but I wonder how much weight a complex articulating tail like that would add, and how you'd balance the C.G.. Maybe just make the boom shorter, if it's more powerful than a standard tail rotor?
Boeing Is Testing A New High-Speed Derivative Of Its Apache Gunship - The Drive
Interesting idea if that's what it is, but I wonder how much weight a complex articulating tail like that would add, and how you'd balance the C.G.. Maybe just make the boom shorter, if it's more powerful than a standard tail rotor?
Tried unsuccessfully to paste three pics of an S-61A with the Roto-Prop installed. A standard 61 tail rotor but with a gearbox that could rotate 90 degrees, thus becoming a thruster when up and away. It was flight tested in the 65-66 time frame.
Last edited by JohnDixson; 31st Oct 2018 at 03:10.
No, according to the link below (mentioned up in the Rotorheads forum here), it's "a tail rotor that could articulate 90 degrees in order to provide forward thrust during level flight." So you'd get a transition back and forth from standard TR anti-torque to pusher prop:
Boeing Is Testing A New High-Speed Derivative Of Its Apache Gunship - The Drive
Interesting idea if that's what it is, but I wonder how much weight a complex articulating tail like that would add, and how you'd balance the C.G.. Maybe just make the boom shorter, if it's more powerful than a standard tail rotor?
Boeing Is Testing A New High-Speed Derivative Of Its Apache Gunship - The Drive
Interesting idea if that's what it is, but I wonder how much weight a complex articulating tail like that would add, and how you'd balance the C.G.. Maybe just make the boom shorter, if it's more powerful than a standard tail rotor?
Also, for that to be correct the pusher propeller would need to be offset from centre even during high-speed flight to counter the torque of the main rotor blades which exists during all phases of the helicopter's flight profile. That, and the image on the briefing slide actually shows the tail rotor attached to the end of the horizontal stabiliser.
Warbird Tech (ISBN 1-58007-027-2) has good coverage in-depth of the Cheyenne from development to disposal...I was doing icing trials in Ottawa in 1969 when it was there as well,tried to `get a ride` but Lockheed were very wary of letting us `furriners` anywhere near it...
MM, a `bent` fin or trimming rudder(through the AFCS) would sort out yaw....
MM, a `bent` fin or trimming rudder(through the AFCS) would sort out yaw....