A plausible Jet Helicopter?

[Whitestar]

I have always been fascinated with helicopters and it was the tv series "Airwolf" that started it off. In the show, it was acknowledged that Airwolf is the only helicopter that can fly at supersonic speeds. Granted, I'm no physicist, but I do know it is impossible for a helicopter to fly at supersonic speeds due to many physical constraints such as the dissymmetry of lift, airflow reversal, retreating blade stall, and air compressibility. For all intents and purposes, Airwolf cannot exist in real life, however, it was established in the show that the only way for it to fly at supersonic speeds was to disengage the rotors and then activate the turbo-thrusters, thereby, it's (somewhat) aerodynamic body would enable it to fly at those high speeds. The odd thing about this is that while the series did feature Airwolf's turbo-thrusters activated, the rotors were never disengaged as mentioned. I'm guessing the reason for this was because the producers did not have the necessary budget, either that or the fact that CGI technology was in its infancy at that time. The reality is, I cannot see how Airwolf could possibly fly at supersonic speeds without having wings.

I have attached a series of photos below that (hopefully) illustrates this concept. Could it be possible for a jet-like helicopter design equipped with wings to disengaged its rotary blades and activate the turbo-thrusters that could enable it to fly at supersonic speeds (at least in theory)? Could these designs make this a plausible jet helicopter?

 

[russ_watters]

Wow, this remains a popular issue, decades later! Please do a forum search for similar threads.

The short answer is yes it is possible. Many (most?) helicopters already have jet engines and there is flexibility in designing for thrust or shaft power or a combination of the two. For example, if you twist the description a little more toward "airplane" versus "helicopter", you get the F-35B.

 

[berkeman]

Could these designs make this a plausible jet helicopter?

Here's a recent thread (you may have seen it already)...

https://www.physicsforums.com/threa...gy-supersonic-helicopter.874943/#post-5494404

 

[boneh3ad]

The bottom line is that you can make almost any shape you want fly supersonic subject to the limits of the propulsion method and the stability and control issues that arise from different shapes. The big issues would be more related to the trade-offs required in efficiency and maneuverability for such a vehicle. It wouldn't be terrible practical.

Here's a recent thread (you may have seen it already)...

https://www.physicsforums.com/threa...gy-supersonic-helicopter.874943/#post-5494404

In fairness, that thread began as a nearly identical question but quickly went off the rails. It also periodically has more people commenting on it with additional crazy nonsense, which is fun. I legitimately enjoyed some of the responses, particularly the guy who suggested that adding winglets to the tail rotor could allow it to go hypersonic.

It's possible this one could remain more serious... maybe.

 

[diogenesNY]

Just in the interest of hanging some numbers on this issue that reflect the current state of the industry:

The Boeing AH-64 Apache attack helicopter is _amongst_ the fastest helos operating

• Never exceed speed: 197 knots (227 mph, 365 km/h)
• Maximum speed: 158 knots (182 mph, 293 km/h)

source: https://en.wikipedia.org/wiki/Boeing_AH-64_Apache#Specifications_(AH-64A/D)

The Airbus Eurocopter X3 is supposedly the fastest helo in operation (knowledgeable individuals may correct me). It has been described as being able, in straight and level flight, to max out at 267mph/430kph/232 knots.

One sample source: https://phys.org/news/2011-05-eurocopter-x3-world-fastest-copter.html
Wikipedia has slightly different specs: https://en.wikipedia.org/wiki/Eurocopter_X³#Specifications




diogenesNY