Laser Beam

Why would you want to cut trees you cannot get to? No point in cutting them down if the wood cannot be harvested.

That's a rather cavalier attitude toward your dance partners, don't you think?

I do not think you fully understand how a laser cuts . . . . .do you.

I suggest you google it and read up on the subject first

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phoenix911

Aw, c'mon guys

Could be planning to trim for power lines

I can just imagine trimming trees during the hot summer when a mouse fart will ignite a forest fire, best forget using a laser to trim trees

when a mouse fart will ignite a forest

oh great, now we're talking about greenhouse gases

Ah yes a major contributor to global warming, mouse flatulence, horrable things worse than cows

I wouldn't be too sure about the mice being a problem. Oz has lots of cows which some have blamed as a major contributor to global warming. Which hemisphere has that big ozone hole over its pole? The Southern Hemisphere! Who has the most vermin? Everybody else!

Personally, I think they should capture that methane and use it to supplement fossil fuels. Think thousands of square km covered by Aussie cows with hoses stuck up their butts and every so often a gas station selling alternative fuel. BP, move over!

Probably 10 years ago, a mate of mine at uni was doing work for LaserDyne on the Gold Coast in Australia, they were developing a truck-mounted laser for the National Parks Service (aka Forrestry Department). The laser was being used to start spot fires for controlled back-burning, a common practice in bushfire threat areas. Now instead of sending guys in with kero drips and having someone in the path of the fire; or dropping fire-bombs from a helicopter and not having accurate control; they can instead park the truck on a near-by hill and start small fires exactly where they need them.

So no, I don't think it will work well as a cutting tool.... unless of course you do it while it is raining to prevent ground fires! You will of course risk the laser refracting off some rain drops and killing some nearby innocents, but other than that..... :-D

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Before anyone replies - yes, I know the laser will anialate the rain drops, not refract off them.

I guess Dr.evil wants another "alen parsons project"

Good tunes that.

You folks have no imagination nor sympathy. Clearly, There are trees blocking this posters otherwise lovely view which he cannot legally get to to cut. so a force at a distance is one solution.

If any of you come up with this, I am warning you that i already have a patent pending for a surface to air cheese slicer that works on this principle, which I developed in case the KrisDel^(tm) flying cheese becomes a popular hit in my parts.

You have been warned!

milo

You've been scooped, my friend. I have a patent pending on a boomerang light saber that does just that. Of course you have to be real careful how you catch it, as it does tend to warm what remains of your fingers. Care for some Sith gouda?

Hello

Why think of cutting the trees. Think of planting more.

May be your purpose will be cut the braches which come in the way of power lines. But once the tool is developed, we humen are so stupid that many will use it to destroy the forests

Ok, no ones mentioned it yet, but why don't you consider using one of the saws that you can dangle from a helicopter (you know, like in the James Bond movie. Yes its real). Works very well.

Yes I have considered laser saws previously, no it ain't a good idea.

Those allready exists

http://www.youtube.com/watch?v=KMQgt5YiD0w

http://www.boreme.com/boreme/funny-2007/helicopter-saw-p1.php

(cannot check the links at my work)

YouTube link works.

Is it wrong to secretly want one of them? Don't have a purpose, or even a large hedge out the front of the house, but part of me just wants to put one of them in my toolbox....

Holy moly! That thing was nuts! Absolutely nuts I tell ya!

But then, well then I saw this.................here

(Sorry if you can't see this Epke, this is another a good one!)

Holy S$@% that guy has great balance and neck muscles.

Contact the US department of defence. Word is they have a few prototypes left over from the "Star Wars" anti satelite program that got canned.

I'm sure they would cash them in so they can spend the mony on some other scheme.

BTW, does this link to the thread on banning lasers because of pilots being targeted?

Maybe Uncle Sam will let you borrow this for an afternoon:

Kind of extreme for hunting mice, I hope the targeting system is better than the patriot used for hunting skuds.

I can just imagine a target which is protected by arrays of retro-reflectors (heck, reflective tape for those on the cheap). Plane zaps target, target blinds plane.

Oops!

Perhaps not a "field laser", but you'll find primacord to be very useful!

Yes it is, and if wrapped correctly the tree is ready for the splitter.

I think more details are needed from the poster...(i.e. where is he and where specifically does he want to cut trees?)

Hmmm....could be an evil scientist in the making...trees could be code for people...hills might actually be Hills Apartment Complex or such...

I see many posts that ask for technological data that could be used for evil...and so many are willing to help without asking questions....

Eeee Heeee heeee heee heeee !!!

(Good thing the government monitors this site dedicatedly)

How about a hundred foot wide magnifying glass?

Great way to burn ants for a distance, not that I would ever do such a thing, or did in my youth, no not me.

Cows with hoses up their butts just seems wrong somehow, I can just hear greenpeace now, oooh that would be just nasty. I wouner where I can get a few thousand feet of hoes?

I don't think it is impossible;

when cutting all what the laser does is supply the heat, material is removed by plasma flow.....i.e. compressed gas.

but it is theoretically possible

maybe we should keep things practical, I'm just reflecting how a CNC laser would work

phoenix911

The gas flow is to keep the cut clean. That makes for both a better-quality and more rapid cutting. But it is not essential. Equally, as you are cutting from an angle from below, collapse across such a narrow gap would mean you would often have to cut out a broad wedge if you are to avoid cutting the same section a very large number of times.

However, I only wrote this as a counter to the "not with today's technology" argument. As I said: I don't consider it to be either economic, nor to be practical - even if the purely financial costs of the necessary equipment and supporting truck became acceptable.

CO₂ lasers are less common than IR laser-diode arrays for cutting and heat-treating applications. Diode arrays are far more compact than CO₂ lasers, have comparable quantum efficiencies (around 60%), require less maintenance, are longer-lived and are not subject to electrode sputtering which tends to coat the interior of the laser cavity - particularly the mirrors/brewster windows. Output power ranges from tens of watts (for very small cutters) to kilowatt-range lasers used for heavy cutting and heat-treating. The diode array shown below is used to heat-treat metal surfaces and therefore lacks the focussing optics required for cutting.

The reason I proposed CO2 as a theoretical demonstrator was the known possibility of self-focussing - which I believe would be even more difficult given the peak-power-density limits of diode lasers (to say nothing of CO2 being at an appropriate wavelength for interaction)

Also, that I'm ignorant in too many areas, such as:
Are these laser cutters single-mode output (I know it is possible, but is it commercial?).
I'm too out of date on material quality - last time I was involved high-power diode lasers were limited to about 1000 hours - very similar to electrically pumped CO2 (which I never actually used...)
And, if using linear optics, I feared the shorter wavelengths would be more prone to defocussing over 100+ feet of air.

Hi All

Thank you very much for taking time to reply my poster. Only rackerman and Physicits looks sincer user of this site who send their good comments. Thanks again.

we are all sincere. after you have been here a while you will get sort of, well cynical I guess, about the sincerity of the poster. And, the nature of your question allows for some good fun.

Am glad you were able to sort out enough hog-wash form our replies to find something useful.

Good luck

Don't think of us as "dissing" your idea or suggesting it is a bad idea; think of us as finding potential problems so you can address them before investing R&D time and fund$. That is one of the big concepts that make forums so powerful - LATERAL THINKING. Many points of view give you a much clearer picture of your project and the issues that may be involved.

My answer was also sincere, instead of using a laser far away (which needs a huge amount off energy maybe combining it with the chainsaw helicopter (laser unit instead of saw) easiest would be just a load cable with a energy feeding cable (plasma electricity) the laser device would clamp on the tree cuts it at an angle (maybe with a piston that nudges it in the proper direction) so it falls away from feeding cable

How are we going to tote all that E around in a helicopter?

Could you reduce the eat sink if it hung under the helicopter?

If my calculations are correct, when this baby hits eighty-eight miles per hour... you're gonna see some serious shit.

Use a turbine to generate electricity?

exxman23 Just doesn't sound like a logging application to me. Loggers are having major cash flow problems now with the housing situation like it is and these things just aren't cheap.The price for the gold on the mirrors would probly pay for a nice tree cutter. The power consumption, maintenance issues and need for a clean environment when servicing just doesn't fit a loggers environment or electro-mechanical aptitude. Sounds more militaristic so who's side is this intended for. I've installed many CO2 lasers for manufacturing and they were finicky enough in that environment, I just can't grasp trying to peak one out in the deep, dark, hilly, damp wilds for long range logging. I don't know that you could transport something like this off road without flexing the resonator at lest a little, a thousands if an inch would change everything to the point of failure. By all means this is possible but its just not practical. J.Conway

Jerrell your bing nice,

...a thousands if an inch would change everything to the point of failure.

1/10th the wave length you are outputting difference between the mirrors will cause a loss of coherence. ( for non Laser people It will quit lasing)

You could probably do it with a gas jet Laser with opposing exhausts but why? The focus would need to be long and due to the heating of the air the kerf would be wide. Something large enough to cut a 24 inch tree in even a few seconds would cut the rocks behind it and vaporise all organics. Not to mention fire watch, afterwards, for a month.

And your right it would cost more than the helicopter, logging trucks, derrick, and expenses of a normal operation. I haven't played with light for some time but a guess would be much more.

Brad