Project challenge -- Dust diverter for landing helicopters
LoopyByteloose
Posts: 12,537
Even in the military, this is a big problem. As the helicopter comes in to land on unknown terrain, dust can be picked up and reduce visibilty to zero.
So the challenge is how to really divert all the dust and regain visibility. I suspect that a minature turbo jet engine blasting forward and down from over the cockpit might do the trick. But of course, the additional thust would have to be offset to retain stability.
Is this or something else a viable solution? You might even get a military contract if you come up with the right idea.
So the challenge is how to really divert all the dust and regain visibility. I suspect that a minature turbo jet engine blasting forward and down from over the cockpit might do the trick. But of course, the additional thust would have to be offset to retain stability.
Is this or something else a viable solution? You might even get a military contract if you come up with the right idea.
Comments
I read a sci-fi book in which a form of ice (a specific crystal structure) was developed which stayed solid up to near boiling temperatures. It was intended to solve the mud problem in the military. It ended up destroying the earth by having the oceans freeze solid.
http://en.wikipedia.org/wiki/Ice-nine
Yep. That looks like the one. Kind of a strange book.
Edit: I couldn't remember the name of the book. "Ice Nine" seemed like as good of a name as any. On closer reading of the Wikipedia article I see you were naming the type of ice not the book. Apparently the book is called "Cat's Cradle". I still think it was a strange book.
I suspect that the issue here isn't so much knowing where the ground is, but where the enemy combatants are. Presumably, during a dust storm they could sneak up closer to a helicopter that is deploying troops.
It seems like water is the main use currently for un-preped areas, other wise polybinder before landing temporally. (http://www.fs.fed.us/t-d/pubs/html/98571319/98571319.html)
Didn't know this was such a big problem for aviation in general http://en.wikipedia.org/wiki/Brownout_(aviation)
I will sleep on this one... *hhmmmmmm??*
So i was thinking about the jet like blower below or on the sides of the copter but that seems to add a lot of weight.
But what if you were able to angle the propeller of the copter up and increased engine speed to compensate for lack of propulsion.
This would drastically increase the airflow and thus blowing away the dust while the copter is at a higher altitude.
Then angle the propellers back to their original position reducing the airflow/ pressure.
This would definitely reduce the amount of dust/ debris and increase visibility very quickly.
Plausible? Good idea? Add-ons?
The only idea I could come up with was a deploy-able skirt around the bottom of the helicopter that would create a laminar air flow that would blow the dust outwards and away from the helicopter. This would create some downwards drag which would have to be compensated for by increasing rotor speed, which might make it more effective, or impractical.
Armed with that, could a computer execute an "autopilot landing"? It might not be the smoothed, but it might be better than crash.
Is "instrument landing" even possible, or is a copter just too touchy?
The dust diverted idea is giving me a headache, it seems the volume of air needed to blow the dust away is bigger than the copter can produce in the first place, and the equipment would be bigger angain than the copter as well.
I don't think an "autopilot landing is possible out in the wild. Instruments might be an aid for the pilot but not adequate for a computer to perform the landing.
Blowing the dust away might (stress on the might) be possible and the equipment could be as simple as an air inflated skirt that diverts the downwards air flow from the rotor to a horizontal flow. When the helicopter gets close to the ground now the air flow becomes a swirling dust filled torus surrounding the helicopter.
I don't think an "autopilot landing" is possible out in the wild. Instruments might be an aid for the pilot but not adequate for a computer to perform the landing.
Blowing the dust away might (stress on the might) be possible and the equipment could be as simple as an air inflated skirt that diverts the downwards air flow from the rotor to a horizontal flow. When the helicopter gets close to the ground now the air flow becomes a swirling dust filled torus surrounding the helicopter.
One of the big problems isn't just putting the thing onto a flat surface. Most pilots are good enough not to have much trouble doing that regardless of visibility, and if the surface is flat they can often carry a bit of forward airspeed to touchdown that puts the worst of the junk behind the cockpit. What really gets you in a low-vis situation is obstacles you can't see. Rocks, stumps, posts, cables, etc. that are hiding in the muck will ruin your day if they're in the wrong place. At some point there may be some sort of radar imaging to get a clear view of the LZ through the crud, but I've not heard of any such thing being made. When you're using airflow to support tens of thousands of pounds of helicopter, trying to finesse that airflow to avoid kicking up dust/snow/debris isn't likely to work. Seeing through it has a lot more potential, so I'd concentrate on that if you really want to try to come up with something.
Driving the airflow radially outward with a skirt means that the airflow moving down through the rotor disk will hit the skirt and apply a downward force on it, reducing the net lift. Driving the airflow radially outward will also reduce the pressure that builds up under the helicopter when the air is compressed between the rotor and the ground, which is called ground effect. Helicopters have two performance specs that are very, very important: the power to hover in ground effect and the power to hover out of ground effect which is much higher. Usually you don't attempt to lift something so heavy you can't hover in ground effect. There are exceptions to that, but doing so is dicey since if something happens so that you can't maintain forward airspeed you WILL settle into the ground. Anyway, if you do anything to reduce ground effect you will seriously reduce the hover performance of the aircraft, and that will mean you can't carry as much weight in cargo, as a sling load, etc. That one's thus a non-starter.
It should easy for a computer to process a stereographic image offset into a graphical (2D) form. It could use 3D modeling which is different from the recreation of 3D depth.
I thought we had technology that could see through "muck" but even if the resolution is low the addition of stereoscopic image processing, (my phrase), should get us closer.
John Abshier
Former helicopter pilot
John Abshier
Former helicopter pilot
Well, I did stress the "might", and it should not be necessary to divert all or even most of the air to radial flow. The air flowing down has to move horizontally once the helicopter gets close to the ground so it might be possible to have a small amount of horizontal air flow prevent the turbulence that causes the dust swirls.