I was looking for some pictures and ran across these. I was curious as to anyone's opinion on them. Photoshop, test birds, etc??
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Anyone seen this before?
- Thread starter lowflier03
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There was some experimentation with an aft facing tail rotor. The Cheyenne (lost to the Apache was the most noteworthy). The Cobra is just a model fairly certain it never made it to prototype.
The bottom line is Igot Sikorsky got it right the first time and nothing as yet has surpassed the standard configuration.
The bottom line is Igot Sikorsky got it right the first time and nothing as yet has surpassed the standard configuration.
I think these were actually in an article from Proceedings awhile back about extending helo range. It advocated going back to Cheyenne-like designs. Will look it up when I get a chance (i.e. after I have my morning coffee.)
vegita1220
User
Could someone explain how an aft facing tail rotor works?
I thought the tail rotor's job was to cancel out the torque effects of the main...
I thought the tail rotor's job was to cancel out the torque effects of the main...
DairyCreamer
Registered User
vegita1220 said:
I'm sure the rudder in the rear of the of the fan section (real or not) provides a similar "anti-torque" effect as a standard tail rotor via the same mechanism as a fixed wing rudder (albeit with the forced airflow of the rear fan).
~Nate
It would have to be ducted, if you look at the Cheyenne it had intermeshed conventional tail rotor as well as an aft facing rotor. You run inot to loss of tail rotor authority problems wiht that system so though faster its slow speed performance is lessened.
I figured maybe this was an advancement on the NOTAR designs. Although that used a ducted fan down the tailboom and a specially designed outlet to create an aerodynamic force.
Mayday
I thought that was the recline!
It looks to me like the "rudder" is sharply canted left for the torque compensation. I suppose that would partially vector airflow but leave the remainder to assist the forward thrust force for a slightly more efficient flight. Seems to me it would make more sense to put the entire empennage on a hinge and make it computer controlled with "fly by wire" type inputs so it could auto-compensate for torque in a hover but progressively straighten out in forward flight (hey, maybe I should run get a patent!).
It's been awhile, but I'll give it a whirl...
I've never seen these pictures, but people float ideas like this a lot in the helo field. They're called compound helos and are an attempt to get around the limited speed of conventional helos. The most famous of compound helos is probably the Cheyenne. The rudder of the ducted tail section would provide anti-torque forces, but at high speeds would push the helo, with the large wings producing lift that the rotors would no longer be giving due to their limitations. However, at low speeds and hover, the wings are just more dead weight. But, at high speeds the rotor becomes dead weight. Just one attempt to try and get around some of the helos inheirent limits.
Sikorsky was toying with an idea called RVR a few years ago to try and increase the top speed of helos and reduce the need for duplicity found in a compound helo. The rotor would have a reduced speed, but would be produce lift in both advancing and retreating stages. When fitted with pusher engines, it would increase the top speed without the need of a wing, but would suffer from several low speed handicaps.
RVR: http://www.unicopter.com/1281.html
Cheyenne:
I've never seen these pictures, but people float ideas like this a lot in the helo field. They're called compound helos and are an attempt to get around the limited speed of conventional helos. The most famous of compound helos is probably the Cheyenne. The rudder of the ducted tail section would provide anti-torque forces, but at high speeds would push the helo, with the large wings producing lift that the rotors would no longer be giving due to their limitations. However, at low speeds and hover, the wings are just more dead weight. But, at high speeds the rotor becomes dead weight. Just one attempt to try and get around some of the helos inheirent limits.
Sikorsky was toying with an idea called RVR a few years ago to try and increase the top speed of helos and reduce the need for duplicity found in a compound helo. The rotor would have a reduced speed, but would be produce lift in both advancing and retreating stages. When fitted with pusher engines, it would increase the top speed without the need of a wing, but would suffer from several low speed handicaps.
RVR: http://www.unicopter.com/1281.html
Cheyenne:
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