h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

It is a nice windless day; there is a helicopter hovering above you and somebody in the helecopter drops a rope down to you.

If you held on to the rope, could you pull the helicopter along?

Erm...Well first you need to ask yourself the all important question, would you want to be able to pull a helicopter?

I sometimes think of silly things like this (I must have too much spare time. )

At least now I have somewhere to ask them, without my friends thinking I am daft; only complete strangers do that now.

If a Hovercraft is stationery and just hovering you would be able to push it along easily, I imagine the same principal would apply to a hellicopter.

I disagree. When you pull the rope to try and move the helicopter there are a number of forces involved. The one that would cock everything up is the downwards one from you pulling. Because the helicopter is above you then you can't help but aplly downwards force which ever way you pull. The downwards force would be countered by the upwards force from the helicopter, you'd fall over and ruin a perfectly good sensible pair of trousers and you'd have failed. It might work though if the helicopter was at the same level as you a couple of feet of the ground?

If you were blown off your feet by the propwash would the force of you pulling on the rope as you were blown away move the whirlybird?

If the hellicopter was just hovering and you pulled on the rope would you be able to pull it downwards if the pilot didn't adjust his trim so to speak. surely the whirybird would only move if the pilot was trying to counteract your downward pull, so as you fell over the whirlybird would rise. This is assumeing that you let go of the rope of coarse.
If there are any hellecopter pilots passing through would you please put us all straight.

But what if the pilot was listening to a really good song on the radio that just happened to come on at precisely the time you lost your footing so he wasn't paying attention?

And that song would have been "Lets Hang On To What We've Got" no dought :-;

Hey how come my simely didn't work Oh! I see why now

LOL... Either that, or something from the Eagles.

I disagree with youo here. For example, if I was to hold on to the rope and lift my feet up, the helicopter would move down due to the extra weight (maybe only slightly). So, I don't see this as being a factor.

Although, I did forget to mention in the original question that the pilot does nothing to aid or stop your efforts.

Well... then how would that effect -my- question of being blown around by the propellers?

This would depend on the altitude of the whirlybird, If it was hovering at 500 feet you wouldn't feel the downdraft. Now suppose you were on top of a building 500 feet high and you were holding the rope that is attached to the thingermejig at the bottom of the hellebird that is parrallel to you, would it it tip the hellecopter up and cause it to fall from the sky or would it pull it closer to you.

Well blow me down.

Or up. Nobody knows anymore. But anyway carry on...

If it was a very light helicopter (as most are), the external force would upset its centre of gravity, and could quickly lead to a situation where the pilot was unable to use the controls to keep the thing under control. It would fall out of the sky, probably towards the source of the external force, and that could really ruin your day!

Hey, Fred. It's nice to know someone else i awake and messing around on h2g2 right now. So have we got this helicopter prob. sussed or what?

Oh yeah... Do something to your home page, you must be even newer here than me.

(Or lazier...?)

Hmm, this is what I reckon will happen:

If the rope was long enough, that the angle between the rope and the ground was fairly shallow, then you could probably pull the copter along. However, you would also be pulling it down to an extent, because the force you are exerting on the copter is in the direction of the copter->you, along the line of the rope.

There is a problem in that you can think of the body of the copter as being suspended from the point at which the rotor blades are attached (the blades exert a force perpendicular to the plane in which they rotate - i.e. straight out of the top of the helicopter).

Now.... If the rope was attached to the copter low down, then your pulling would make the bottom of the copter tilt towards you. Some of the force which was holding the copter in the air (counteracting gravity), will now be acting AWAY from you.

So... if the rope is attached at the bottom of the machine, then I think the copter would move away from the direction in which you are pulling, and would also probably drop a bit (due to "ground force", it wouldn't actually crash into the ground tho').

Without actually doing any maths, my gut feelings are:

YES, you would be able to pull the copter along, but maybe only if the rope was attached high enough up on the copter's body.

Phew.

Just in case any kids are reading this:
If you see a helicopter with a rope hanging down, DON'T try to pull it or hang on to it! You may have read some pretty fascinating theories on this thread, but the truth is you can't really predict what's going to happen. There are so many different factors involved. And if it's a bungy-cord hanging down, and you decide to try to pull down the helicopter, and the pilot wakes up and pulls the chopper back up, you'll be able to add "first-hand (or perhaps -head)experience with a blender" to your resumé!