[Closed] Helicopters and tunnels.

Well they can fly through hangers so I would have thought a tunnel would be possible but perhaps a touch bigger that MI size and blade touching!

If its an RC there would be no problem, if your talking shinook full metal jacket type jobbie I doubt. Don't know what chopper you mean though cos I'm watching BGT

getting it to fly level, at a set height above the roadway and a set distance from the walls, it would be easier to put it on a tag line with the rotors going and pull it through.

Also who is going to close a tunnel down while they film it.

BGT

Yep, looks like they can but for how long ?

The tunnel was clearly too narrow.

I too wondered about whether airflow might be an issue, while hating Tom Cruise.

As you say, a proper film is now on.

Just before the train and helicopter go into the tunnel at the end Mission Impossible they go past my workshop.

they go past my workshop.

Yep, looks like they can but for how long ?

What if there was a conveyer belt in the tunnel?

Think that you tube clinches it and a lifetime flying ban for the pilot when he shows off his copters ID details and his face at the start of the clip (or is pilot in left hand seat in a chopper?)

Helicopter pilot is on the right, opposite to a plane where the captain is on the left.

Mission impossible is awful. Anything with Tom cruise is awful, bgt is where it's at, although it's just finished so looks like it might be die hard 🙂

so looks like it might be die hard

I hope so. When I get rich I'm going to build a tunnel from my house to where I want to go and travel through it in one. I've been planning this since I was 9.

I was wrong bgt is still on phew!! Bruce Willis without hair is definatley worth a look, with hair not so much. I don't think I was born when moonlighting was on

Put your shoes on Bruce, you'll only regret it later.... 😯

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Pfft yeah yeah

Anything with Tom cruise is awful

Anything with Tom cruise is awful

I am no Tom Cruise but Magnolia is brilliant as is Risky Business, I liked Collaterol as well but that might be my admiration for Michael Mann

Mission impossible is awful. Anything with Tom cruise is awful, bgt is where it's at, although it's just finished so looks like it might be die hard

Can't watch anything with the annoying grinning scientologist dickwad either.

It's all very nice discussing tha talents, or lack of, of Mr Cruise. I'm still interested in knowing the limitations of helipocters flying in tunnels.
Anyone?

My physics teacher once posed the question about a helicopter flying in a verticle tube with a diameter the same as that of the rotors. Sadly I can't remember the answer or indeed if one was actually agreed on.

My physics teacher once posed the question about a helicopter flying in a verticle tube with a diameter the same as that of the rotors. Sadly I can't remember the answer or indeed if one was actually agreed on.

Collateral was very good, despite having both Jamie Foxx and Tom Cruise (world class bellends) in it. Tropic Thunder - very good.

Everything else - utter pish.

The answer is in the name of the film surely. Mission IMPOSSIBLE.

I'm a librarian not a theoretical aeronautics engineer, however my expert view is no, as helicopters need some kind of downdraft. And they are rubbish in the wind, and the tunnel would have a wind blowing along it.

Why would it matter? I presume that the blades of a helicopter force air down to propel the craft upwards. Why would it matter having a surface above the blades? Hovering may be compromised by airflow issues (I'm guessing); but a moving helicopter wouldn't be affected. All of this of course assumes that none of the helicopter hits the tunnel. Or have I messed the point as to why the tunnel is a problem for flight?

A helicopter in a sealed vertical tube with the rotor blades just touching the sides would yo-yo up and down (ignoring tail rotors and baby robins)

It could fly and hover in a tunnel, not sure whether it would need more power or less though - there's restricted air flow into the rotor, but the wash would probably provide more lift?

Edit: you'd have to be careful not to fly into the roof, and lift would drop as you got close to it.

And Die Hard is an awful film. Top Gun more than makes up for everything else Tom Cruise has inflicted on humanity.

I'm not sure if this is fake, but it's a Canberra flying through a hanger

[img] http://t0.gstatic.com/images?q=tbn:ANd9GcRG48g84rlOAVRu_RVVRpTfAuRRe7si0UyS2hsRf_lwK9Pggi5LvUpxP4QWhg [/img]

Anyone who thinks Top Gun is rubbish needs their head examining.

Magnolia is well good, and particularly funny given that Cruise's real life tantrum about scientology was way better than the one he has about his parents and his life coaching thingy in the film. 😀

I've tried flying my indoor micro rc heli through the house and it's very difficult due to the recirculation of the air flow from the rotors which creates TBE (toilet bowl effect) in the limted space.

I think it would take a great deal of skill to fly a heli through a really long tunnel and a death wish. Possibly impossible if its too long..

I agree with your reasoning for the lift-off and hover. NO WAY, the recirculation would be so severe as to produce an inflow into the top of the rotor that removed virtually all of the incidence of the blade sections. If you were to continue adding collective pitch eventually you would have the lift force for the aerofoil section pointing backwards (i.e. DRAG, resisting rotoation) and just consuming torque and power without producing any lift in the vertical direction.

Furthermore, the whole process would be horribley unsteady, and their would be lots of uncommanded pitching and rolling that at the high power settling we are discussing are likely to rollover the aircraft. However, the comment about ring vortex is not accurate. Ring vortex is when the vortex structures in the wake build up under the disc and in the plane of the disc due to a high Rate of descent. In the tunnel case the same vortex structures would be recirculated by the tunnel wall and injested from the top of the disc. Much of the unpleasantness would result in the same manner, i.e. high loads, high vibration, uncommanded pitching and rolling but it wouldn't be Ring Vortex it would be Blade Vortex Interaction due to Recirculation.

The interesting one is high speed foward flight. Fundementally as long as the tunnel was big enough, then I see no reason why a helicopter could not be flown into it at speed, through it and out the other end. As we know in high speed flight the wake is skewed almost horizontally behind the helicopter, and the streamtube in which the wake can be considered to exist in the regime is much flatter and diagonally orientated. So the flow into and out of the rotor would be affected only subtley in high speed flight. I guess with a lightly loaded rotor and the helicopter flying at say 5ft, you would need about 1.5 rotor diamaters of head room in a semi-circular tunnel. (The number is a finger in the air guess I haven't done the sums!)

However, I think that the wake of the helicopter would be very severe, again due to recirculation and so a second helicopter would not be able to follow......which brings me onto the final point. Even if you could fly a helicopter in a tunnel, you couldn't chase a train - the wake from the train would flip you over!

I am no Tom Cruise but Magnolia is brilliant as is Risky Business, I liked Collaterol as well but that might be my admiration for Michael Mann