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Quadcopters
type568
Member #8,381
March 2007
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I've got the topic for a while now, but now I was gifted a little toy so the topic resumed in my mind.

Why don't we make big enough quadcopters(rather octocopters) to safely and quickly transport us above all traffic jamms?

Logically I assume the only technical issue with it is electric power for the stuff, but somehow I think the modern batts could could allow us to fly something like this for some hour or more. Should be controlled by a computer gettings us from A to B of course, no manual control for safety reasons.

And heck.. Sell your estate in the centers of your cities then.

P.S:
I'm quite clueless how to calculate the weight and voltage & amperage of the batts, engines, etc'
But the topic is certainly intersting.

Chris Katko
Member #1,881
January 2002
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Is this one of those "I'm drunk and/or high?" posts?

Quad-copters are extremely lightweight and only a small percentage can even lift a camera.

Electric engines are great but batteries still don't have enough power density to be used in most aerial vehicles.

If you're flying yourself, now everyone needs pilots licenses and official maintenance procedures of each quad copter because you DO NOT want these things falling out of the sky onto you, your car, or your business.

You also need an official channel, height, rules, etc for transporting people around cities. "Road rules for the sky" Gravity and falling has a HUGE amount of energy associated with it, which is why cars crash, but airplanes explode.

If they're flying themselves, now you've got to design something that has a 0% chance of failure. Because when a person fails, they get blamed. When a quadcopter fails, Amazon (or Amazon's insurer) gets sued to the ground.

I did some grad work with welding robots. In the USA and world, welders are certified. How do you certify a robot? Well, you have to basically design tons of tests that would show, to a reasonable authority, that these robots will weld reliably enough (beyond that of a human) to depend on. Because you can't certify the individual person, you have to certify all of your robots of a particular model. Now instead of just welding a bead on a Navy submarine with no humans in the way, you're flying in the public with people's children playing in parks. The potential for danger is orders of a magnitude higher!

Now, to clarify, I'm not calling you a moron or anything like that. But this is a very difficult thing to do.

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type568
Member #8,381
March 2007
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Is this one of those "I'm drunk and/or high?" posts?

Honestly neighter.

Append: yeah, heh.. Well. Actually I think the benefit is wort the hassle of making a copter that doesn't fall. Notice I wrote octacopter, cos I do think it can be an independent enough system to be falling way less often than our current aircraft(it has way more in flight control, and it can be quite fail tolerant).

The problem is indeed power.. But my point is that having this thing flying at 150 kmh for 20 minutes may already make it quite worthy for transportation.

Ben Delacob
Member #6,141
August 2005
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A lot of people bring up flying car wish posts. I'm surprised there aren't more for quadcopters. My response always remains the same: Even if it's safe, it would be very, very loud. I like not living at an airport and the ability to go places that aren't airports.

Edit: Though I guess the electric ones might not be the worst, that many blades would still probably be extremely loud when used full scale, by the masses.

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Sevalecan
Member #4,686
June 2004
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Is this one of those "I'm drunk and/or high?" posts?

Quad-copters are extremely lightweight and only a small percentage can even lift a camera.

No, because it's actually quite a nifty idea. There are at least one or two companies working on 'hover bikes' that use this idea, with two or four rotors. See See hover-bike.com.

Quote:

Electric engines are great but batteries still don't have enough power density to be used in most aerial vehicles.

Right, regular petroleum-based fuels have much greater energy density than batteries. Best to stick with these when you want to reduce weight on a craft.

Quote:

If you're flying yourself, now everyone needs pilots licenses and official maintenance procedures of each quad copter because you DO NOT want these things falling out of the sky onto you, your car, or your business.

You also need an official channel, height, rules, etc for transporting people around cities. "Road rules for the sky" Gravity and falling has a HUGE amount of energy associated with it, which is why cars crash, but airplanes explode.

Not all crash landings involve explosions. And when they do explode, it's usually a big ass jet. Probably not unreasonable to expect those massive fuel tanks to burst. and mix with the extremely hot engines, just running jet engines practically with exposed flames out the rear... I surmise that a piston-powered aircraft is less likely to explode in this scenario.

Quote:

If they're flying themselves, now you've got to design something that has a 0% chance of failure.

No machine on earth has a 0% chance of failure.

Quote:

Because when a person fails, they get blamed. When a quadcopter fails, Amazon (or Amazon's insurer) gets sued to the ground.

Also untrue. This is why even general aviation is prohibitively expensive. Arguably probably around 95% of airplane crashes are due to pilot error. However, aircraft manufacturers have to charge a lot of money for parts and whatnot because they'll get sued when the stupid pilot drives the plane into the ground. As a general comparison, a new engine for one of my dad's planes would cost around $30-$40k USD... A new engine for a car would probably cost $5k or $6k. And the aircraft engine in this particular case is much less complicated in terms of construction and how it works.

Quote:

I did some grad work with welding robots. In the USA and world, welders are certified. How do you certify a robot? Well, you have to basically design tons of tests that would show, to a reasonable authority, that these robots will weld reliably enough (beyond that of a human) to depend on. Because you can't certify the individual person, you have to certify all of your robots of a particular model. Now instead of just welding a bead on a Navy submarine with no humans in the way, you're flying in the public with people's children playing in parks. The potential for danger is orders of a magnitude higher!

Now, to clarify, I'm not calling you a moron or anything like that. But this is a very difficult thing to do.

As if the first car or airplane was an exceedingly simple undertaking. Besides, technically you could already go get an ultralight and fly over these areas without even a pilot's license. I wouldn't wanna fly that slow though >:(

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type568
Member #8,381
March 2007
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If it involves fossil fuels it kills my idea. What I thought maybe real is having some 8 propellers, and some 15-40 minutes flight at ~150kmh, to robotically get me from A to B, while achieving high fail safety on cheap parts due to redundancy.

Well, now if these bats are so damn heavy, perhaps hydrogen cells? :D

(I'm still not drunk, & there are no bears who are forcing me to type this around.)

Chris Katko
Member #1,881
January 2002
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Sevalecan said:

Besides, technically you could already go get an ultralight and fly over these areas without even a pilot's license.

Ultralights are illegal anywhere near civilization without a pilots license for all the reasons I mentioned.

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type568
Member #8,381
March 2007
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Well, you're wrong.

wiki said:

In the United States no license or training is required by law for ultralights, but training is highly advisable. For light-sport aircraft a sport pilot certificate is required.

Unless wiki lies, which well, is possible. But not likely on such a topic.

Chris Katko
Member #1,881
January 2002
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Without a license, ultralights cannot:

- Carry more than one person, or have two seats. [1]
- Cannot weigh more than 1320 lbs pounds. [2] Actually, 254 pounds empty according to this page. [2b]
- Cannot go faster than 64 MPH. [3]
- Can only be flown during daylight hours and no where near populated areas. [see 3 and 2b]
- If classified as a Light Sport Aircraft, cannot have variable pitch propellers (required for any kind of modern performance), or exceed 51 mph. [4]
- Cannot fly anywhere near an airport, and many controlled airspaces, partially because ultralights do not have radios. [Source]
- Altitude limitations are by area, subject to federal, state, and local laws.

I looked into building an ultralight when I was in college. There were much more laws than I expected.

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June 2006

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Chris Katko
Member #1,881
January 2002
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Wow, they mention another problem. Wind (and but miss noise!). Helicopters put off enormous amounts of wind just to take off. Now, cut the weight down by a generous amount 10x from a typical lightweight general purpose news company or hospital chopper.

You'll likely be dropping 10x the wind. Now add 10, 30, 50, 300 of these flying around at all times above your house.

It would be deafening! :o

School kids have already been shown to experience significant learning disabilities at schools located adjacent or nearby airports! It affects both their memory, attention.

http://www.designshare.com/Research/LMaxwell/NoiseChildren.htm
(And various others, just google some variation of Airport Noise School)

Don't get me wrong, a future with flying cars would be great. But I'm not aware of any technologies that bypass the biggest problems. (Energy storage, humans, and noise/wind, and humans.)

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type568
Member #8,381
March 2007
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No, it'll fly high enough for it not to make too much trouble. I'd guess it'd be quieter than noise we used to hear from cars, with exception of take off & landing.

And actually I don't think it'll be noisy.. Helicopters rotors are noisy, while fans are kind of quieter.

Here is a discussion about noise of helicopters. I kind of always thought the noise is generated by varying angle of attack of the blades during each cycle. Now I ain't certain it's that simple though. But it does make sense.

Chris Katko
Member #1,881
January 2002
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I'll give that link a read but:

type568 said:

Helicopters rotors are noisy, while fans are kind of quieter.

In my experience, smaller fans have to be run faster. Higher frequencies contain less energy per amplitude, so for the same energy exerted to lift (assuming equal efficiency), the amplitude is much higher. (e.g. a 200-watt subwoofer is nothing. A 200-watt tweeter/megaphone is deafening.)

I've got a few drone/RC brushless motors. Merely lifting a couple pounds, the two motors with about 12"-14" diameter rotors were very loud!

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gnolam
Member #2,030
March 2002
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... ahaha. The Moller SkyCar sca... I mean, venture is still alive?

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