Airwolf myths

ironhold
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Airwolf myths Jun 19, 2017 0:50:41 GMT

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Post by ironhold on Jun 19, 2017 0:50:41 GMT

This comes from the TV series "Airwolf" and related media -

"Proof Through The Night" -

String and Dom need to take Airwolf into the middle of Russia in order to extract a deep-cover operative. Even with a refueling aircraft on-station in the Baltic, the only way they'll have enough fuel for the trip is if Airwolf goes in unarmed in order to make room for more fuel. Unfortunately, the Russian military has figured out that the operative is probably hiding out somewhere near where his brother-in-law lives, and so they have patrols running.

In order to get the guy and go, String has to use the backwash and rotor wash to shake off the local militia.

He starts by deliberately flying circles around a "Little Bird" type helicopter, confusing the crew; he then hits the booster while flying past it, creating a wash that throws the little bird about. The already-disoriented pilot can't recover, and the little bird ends up on its side.

He then uses a mix of wash to flip a jeep, blocking the road so that a following troop truck can't get past. This forces the militia to dismount, and their bullets can't penetrate the armor.

So, could wash from a helicopter do these things?

silverdragon
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Airwolf myths Jun 19, 2017 6:16:42 GMT

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Post by silverdragon on Jun 19, 2017 6:16:42 GMT

"Yes but you wouldnt want to try"?...

How close would you have to get to wash out another aircraft, bearing in mind how close the Red Sparrows of the RAF, Blue Angels of USAF and other military display teams?.

To was a vehicle off its tyres, you would either need a hell of a size bent banana Chinook or that osprey thing the USAF use, it takes a lot to do that.
The wash of a rotor wing is massive, but only if you are very close?...

-x-clacks-GNU Terry Pratchett----Release the Clan Mac Feegle, awae hame ye scunners.[p]Most of my Job is avoiding Stupid. ...You cant Fix Stupid. Especially when you turn Left at Hammerhead.

mrfatso Evil Senior Member Posts: 3,856	Airwolf myths Jun 19, 2017 9:40:44 GMT Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by mrfatso on Jun 19, 2017 9:40:44 GMT Bearing in mind that in the TV series Airwolf was a helicopter capable of supersonic speeds its rotor wash is likely to be stronger than a Chinook, but unfortunately not something that we could replicate.

the light works
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Airwolf myths Jun 19, 2017 14:22:17 GMT

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Post by the light works on Jun 19, 2017 14:22:17 GMT

Jun 19, 2017 9:40:44 GMT mrfatso said:

Bearing in mind that in the TV series Airwolf was a helicopter capable of supersonic speeds its rotor wash is likely to be stronger than a Chinook, but unfortunately not something that we could replicate.

you are forgetting that it is still a relatively light airframe, and Newton's law still applies.

I suspect that coming out of a dive directly on top of a smaller helicopter would probably disrupt things for the pilot, and depending on the pilot it has a chance of being unrecoverable.

as for flipping the jeep, my first response is "how big is the sail on the Jeep?"
I know a coast guard jayhawk can't flip our water rescue pickups, but if the jeep was being driven, and is open topped, it could have disrupted things for the driver enough to cause HIM to lose control and crash.

there WAS a feelgood news story over the winter about a news chopper pilot who saw a deer bambied on a frozen lake and used his rotor wash to slide the deer to the shoreline, where it could get back up.

silverdragon
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Airwolf myths Jun 20, 2017 5:54:17 GMT

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Post by silverdragon on Jun 20, 2017 5:54:17 GMT

Jun 19, 2017 9:40:44 GMT mrfatso said:

Bearing in mind that in the TV series Airwolf was a helicopter capable of supersonic speeds its rotor wash is likely to be stronger than a Chinook, but unfortunately not something that we could replicate.

Ah, No, Not exactly...

I watched the show a few decades back when it was first on, so, if anyone can correct this, feel free, but if I remember right...
It was a perfectly normal helicopter at slow speeds. But the engine was "On steroids", being a full jet engine.
They kind of "fudged" the science, but I sort of made sense out of that fudge, and the helicopter went into autogyro mode with free spinning blades at higher speeds because you cant do supersonic in a bladed engine aircraft because of the problems of rotor tips passing through the speed of sound and control surfaces doing exactly the opposite of what you expect.
Therefore, the rotor was left to spin freely under the speed of sound...
And that bloody big jet engine powering the rotor at low speed was put in "light the afterburners and stand back" mode where it provided direct exhaust thrust backwards to push the aircraft forwards.

IIRC they even semi-braked the blades to keep them under the speed of sound?.

Which kind of invites a pure separate side myth that can you actually do that with a helicopter anyway?.
My guess is no you cant...
Otherwise the RAF, My old Mob, would know that already, and wouldnt let the Yanks get away with doing it first.
We would have a helicopter that could do that in service right now if that could be done.

Can you autogyro a chopper and use the jet engine for thrust backwards alone?..
Plausible.
Can you get supersonic speeds in that same aircraft?.
Doubtful.
I suspect variable blade geometry may be the key to that, but as no one has managed to invent a rotor with "Transformer" abilities to change the rotor shape and length mid flight ....
I suspect the problem will be in "too MUCH lift" in autogyro mode and the problem of the fudged science with keeping the tips under Mach 1.. just how the hell DO you keep them from over rotating without burning out the braking system?.. if you can even invent brakes for a rotor of that type.

Am I over-thinking this?.

Or do we know someone who has a chopper capable of autogyro mode they dont mind lending out to a bunch of nutters who want to strap a jet engine to it?.

Would I take a ride in that?.. Hell Yeah. Just strap a chute to me and I am good to go...?

-x-clacks-GNU Terry Pratchett----Release the Clan Mac Feegle, awae hame ye scunners.[p]Most of my Job is avoiding Stupid. ...You cant Fix Stupid. Especially when you turn Left at Hammerhead.

the light works
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Posts: 38,322

Airwolf myths Jun 20, 2017 13:53:14 GMT

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Post by the light works on Jun 20, 2017 13:53:14 GMT

Jun 20, 2017 5:54:17 GMT silverdragon said:

Jun 19, 2017 9:40:44 GMT mrfatso said:

Bearing in mind that in the TV series Airwolf was a helicopter capable of supersonic speeds its rotor wash is likely to be stronger than a Chinook, but unfortunately not something that we could replicate.

Ah, No, Not exactly...

I watched the show a few decades back when it was first on, so, if anyone can correct this, feel free, but if I remember right...
It was a perfectly normal helicopter at slow speeds. But the engine was "On steroids", being a full jet engine.
They kind of "fudged" the science, but I sort of made sense out of that fudge, and the helicopter went into autogyro mode with free spinning blades at higher speeds because you cant do supersonic in a bladed engine aircraft because of the problems of rotor tips passing through the speed of sound and control surfaces doing exactly the opposite of what you expect.
Therefore, the rotor was left to spin freely under the speed of sound...
And that bloody big jet engine powering the rotor at low speed was put in "light the afterburners and stand back" mode where it provided direct exhaust thrust backwards to push the aircraft forwards.

IIRC they even semi-braked the blades to keep them under the speed of sound?.

Which kind of invites a pure separate side myth that can you actually do that with a helicopter anyway?.
My guess is no you cant...
Otherwise the RAF, My old Mob, would know that already, and wouldnt let the Yanks get away with doing it first.
We would have a helicopter that could do that in service right now if that could be done.

Can you autogyro a chopper and use the jet engine for thrust backwards alone?..
Plausible.
Can you get supersonic speeds in that same aircraft?.
Doubtful.
I suspect variable blade geometry may be the key to that, but as no one has managed to invent a rotor with "Transformer" abilities to change the rotor shape and length mid flight ....
I suspect the problem will be in "too MUCH lift" in autogyro mode and the problem of the fudged science with keeping the tips under Mach 1.. just how the hell DO you keep them from over rotating without burning out the braking system?.. if you can even invent brakes for a rotor of that type.

Am I over-thinking this?.

Or do we know someone who has a chopper capable of autogyro mode they dont mind lending out to a bunch of nutters who want to strap a jet engine to it?.

Would I take a ride in that?.. Hell Yeah. Just strap a chute to me and I am good to go...?

the airframe was also a lifting body, as I recall, which would allow them to reduce the pitch on the rotor blades, and get less lift from them. - which would reduce the force trying to spin them.

not that I believe the "science" actually adds up.

Post by ironhold on Jun 19, 2017 0:50:41 GMT

Post by silverdragon on Jun 19, 2017 6:16:42 GMT

Post by mrfatso on Jun 19, 2017 9:40:44 GMT

Post by the light works on Jun 19, 2017 14:22:17 GMT

Post by silverdragon on Jun 20, 2017 5:54:17 GMT

Post by the light works on Jun 20, 2017 13:53:14 GMT