After having looked at some of the US compound helicopter designs that unfortunately never quite made the cut, I'm convinced that one or more of them was what the TV show Airwolf sought to emulate, at least to a certain extent.

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That Sikorsky would have been awesome in action. It looks like a whiff in the photo. 
https://sikorskyarchives.com/home/sikorsky-product-history/helicopter-innovation-era/sikorsky-s-67/

Oh yes, the S-67.

Sadly I saw that go in at Farnborough in the 70s, and it killed both crew members. It was very agile, but just not agile enough on that occasion.

Course there's also this thing, but the Sikorsky does look better.  The Cheyenne was supposedly projected to be cheaper, and it had the pusher prop for high speed flight.  The S-67 had a swiveling tail rotor for that, and the Army was skeptical of how well that would work.



With that being said, if Sikorsky had added say, a pair of J-85 turbojets in the wing roots instead of having that swiveling rotorprop thing, they could have come about as close as you can feasibly get to what Airwolf was purported to be capable of.  We're not talking supersonic speeds or anything, but it could have been capable of more than 300 knots I'd say, maybe even as much as 400 knots.  The only downside is that having those engines running would significantly increase fuel consumption, which i presume was the reason they went with the more efficient if less speedy proprotor design.  I really need to print up a model of one of those things and whiff that configuration together sometime 

Quote from: PR19_Kit on September 17, 2024, 02:41:39 PMOh yes, the S-67.

Sadly I saw that go in at Farnborough in the 70s, and it killed both crew members. It was very agile, but just not agile enough on that occasion.

Sad indeed.

Cheyenne was too fast and expensive for the Army's needs and encroaching on USAF territory.  Ironically, Lockheed had ironed out 99% of the bugs when it was axed.

The S-67 was not the Sikorsky AAFSS competitor against the AH-56 and it did not have the Rotoprop swiveling tail-rotor. The S-66 was the AAFSS competitor and while it was never built the Rotoprop was tested on a modified S-61.

The S-67 came along after the AAFSS competition was over and done with.

Sikorsky S-66

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Speculative drawings from Jens Baganz (Jemiba on Secret Projects).
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S-61A Rotoprop
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Quote from: The Wooksta! on September 17, 2024, 02:57:20 PMCheyenne was too fast and expensive for the Army's needs and encroaching on USAF territory.  Ironically, Lockheed had ironed out 99% of the bugs when it was axed.

Interesting.  I have always heard that the Army really wanted the AH-56 and they ended up getting stuck with the Cobra instead because that helicopter had already been pressed into service in Vietnam, was supposedly "good enough", and Bell wanted to make as much money off of it as possible.  And then of course there was USAF deciding not to stay in their lane, the AH-56 was still a helicopter at the end of the day, even if it did have wings.  To be fair to the Cobra it eventually became the AH-1Z, which is a fantastic attack helo for the USMC - if a bit limited by its lack of a mast mount for the Longbow radar.  But the AH-56 would have essentially brought the capabilities of the Apache (minus the Hellfire and plus greater speed and payload) about 10 years earlier. 

One problem was that the Army decided to give up high speed flight in favor of the tactic of hovering behind hills and using the terrain to conceal their helos. That's why the Apache is not the worlds fastest chopper. So both Sikorsky and Lockheed were working on something the Army eventually decided it didn't need.
Those Sikorsky proposals look like great whiff material.

That 'rotoprop' idea has always puzzled me.

When they swivelled the rotor round to the rear, did the pilot have to lean VERY heavily on the rudder pedals to trim the over-sized rudder to counter-act the still present main rotor torque affecting the rest of the airframe, or was there something else going on? If there was it's not at all obvious.

AFAIK no-one else ever tried the idea, or did they?

Always thought the Cheyenne had a reptilian look and camouflage enhances it.

At high speed the tail fin provides enough control that the tail rotor is no longer needed. It only produces drag at that point. Hence the idea of turning it into a pusher prop for extra speed.

Quote from: kerick on September 18, 2024, 06:35:12 AMAt high speed the tail fin provides enough control that the tail rotor is no longer needed. It only produces drag at that point. Hence the idea of turning it into a pusher prop for extra speed.

OIK, so why don't Sikorsky, and other helicopter manufacturers do it these days?

Quote from: PR19_Kit on September 18, 2024, 07:23:44 AM

Quote from: kerick on September 18, 2024, 06:35:12 AMAt high speed the tail fin provides enough control that the tail rotor is no longer needed. It only produces drag at that point. Hence the idea of turning it into a pusher prop for extra speed.

OIK, so why don't Sikorsky, and other helicopter manufacturers do it these days?

Needless complexity and the normal
operating enviroment of most helicopters
doesn't require fuel-sucking high-speed
flight. It might be useful for short bursts,
but most of the time its just something
else to break.

I think the fan in fin was an attempt to lower the drag at higher speeds. Not sure how well it works. Seems that if it made a big difference more would use it.