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[P]
Another backpack helicopter

By tftp in Technology
Wed Jun 12, 2002 at 02:04:14 PM EST
Tags: Hardware (all tags)
Hardware

Browsing the Web, I found this today:

"Omsk aerospace association Polyot (Flight) developed a backpack helicopter: Yula. This aircraft does not have any analogue in the whole world. The weight of the helicopter is 20 kilos, the flight speed is 120 kilometers per hour, the flying height is 1000 meters, and the active time of the flight is 25 minutes. When the helicopter is folded, it looks like a roll 1.5 meters long."


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The link is here (in English), and here in Russian.

I saw many designs like that. The common detail of all of them was use of hydrogen peroxide H2O2 as a fuel. This could be OK for a soldier, but everyone else would be quite a reckless person to deal with the substance, so violently corrosive it is. If not all fuel is "burned" in the engine (there is a catalyst grid to break it up) then remaining vapors can get onto pilot's clothes, body and get inhaled too. Hardly healthy...

But this helicopter seems to be different. The linked article says that the jets at the ends of blades use the fuel that consists of two components; if true, this would be a key difference because these components can be safer, and maybe even easy to maintain. What exactly components are used? Article says nothing about that. A different interpretation of the text (it is vague) says that more than one kind of fuel can be used (but only one component). If so, the fuel could be any standard jet fuel (kerosene) or equivalents. But then such an engine would need a high airspeed to start up - how did they do it if the design went this way? But obviously it has been solved, and the thing flies!

Another "interesting" detail is that helicopters of this sort have absolutely no protection of a pilot against anything untoward that might happen. Collision with a bird could be unpleasant even when you just walk on the ground (proof is here). Imagine how will it feel if both you and the bird fly at 100 km/h ;-) Rain and clouds can also affect the pilot (not the aircraft). But the relatively short flight time probably limits the danger of a bad weather.

This design, with its weight of only 20 kg, definitely makes the contraption practically usable. Definitely, it is not a car, and not a bus, but it can find plenty of uses already. If the FAA (or your local equivalent) allows such a flight gear, I am sure thousands of people would gladly buy them - especially if the price is right (anything below $2,000 would be OK, I guess, for a start). That is in range of motorcycle prices, and way below of any used car price (not even mentioning a very, very used airplane).

Looks like flying of such a helicopter would be not any more dangerous than flying an ultralight airplane, for example. In fact, it could be safer because there is no "stall speed" that you have to exceed in order to remain in the air. You can fly as high or as low as you want. Most important practical benefit would be flying across bodies of water, this is a problem in many places because you can't build bridges everywhere. You can fly over fields, over ravines, over territories where there are no roads; this way you can quickly get to places which would require hours of driving around in a car.

Another aspect of safety of such flights has been taken care of already. Years ago, if you were to make an emergency landing somewhere in a field, at night, you would be thoroughly frozen by the time you reach a phone. Today all you need is to make a cell phone call to your local AAA equivalent, send your GPS position, and wait 15 minutes for someone to come - maybe with tools, maybe with fuel, maybe with a car to load your helicopter on.

In-flight safety, high in the air, can be dealt with too. Normally, helicopters and parachutes don't mix, because if you decide to jump, you'd fly right through the spinning blades, and that is not practical. However in this design the pilot probably can abandon the helicopter safely. There is always an option of jettisoning the blades, and then deploying a built-in parachute. With such modifications, the aircraft would be safe for everyone.

I hope eventually some of those prototypes find their way to the manufacturing. People buy flights to ISS, of all places, for $20M - I'd guess a lot more people could afford a personal helicopter!

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Another backpack helicopter | 79 comments (69 topical, 10 editorial, 0 hidden)
Ha! (3.50 / 6) (#1)
by m0rzo on Wed Jun 12, 2002 at 01:27:07 AM EST

You think the FAA would ever permit citizens to fly something like this?! Just another device to fly into a building. A terrorists dream! Yes, you can blame the terrorists for our boyhood dreams being spoilt. We. Will. Never. Have. Flying. Cars. Blame the terrorists, I tells ya.


My last sig was just plain offensive.

I can already see the headlines (4.60 / 5) (#4)
by Stereo on Wed Jun 12, 2002 at 02:29:51 AM EST

Terrorist attack: Luxemburgish jackass Stereo flies backpack helicopter into skyscraper. One dead, nil wounded

kuro5hin - Artes technicae et humaniores, a fossis


[ Parent ]
You think so? (5.00 / 1) (#13)
by m0rzo on Wed Jun 12, 2002 at 06:41:10 AM EST

Strap a few pounds of x explosive (x being your explosive of choice, be that semtex, c4 or tnt) and you've got an effective, guided, arial bomb.


My last sig was just plain offensive.
[ Parent ]

Mostly guided. (4.00 / 1) (#18)
by i on Wed Jun 12, 2002 at 08:36:43 AM EST

These things are rather hard to fly. You can probably get better results with a glider (? -- deltaplane). A lot cheaper, too.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]
Why would you need an helicopter for that? (4.00 / 1) (#19)
by Stereo on Wed Jun 12, 2002 at 08:57:57 AM EST

You could use a car or carry a big cardboard box full of explosives around and make it look like you're moving furniture...

kuro5hin - Artes technicae et humaniores, a fossis


[ Parent ]
Not wishing to give anyone any ideas but... (none / 0) (#20)
by m0rzo on Wed Jun 12, 2002 at 09:18:27 AM EST

Imagine descending into a football stadium during a match, or into an area where cars can't go or, for that people, pedestrians..then blowing yourself up! Lots of damage. Anyway, I'm just being hypothetical and I'd love to see these things in full production but I know they'd never be allowed.


My last sig was just plain offensive.
[ Parent ]

Have you noticed that (none / 0) (#14)
by FredBloggs on Wed Jun 12, 2002 at 06:45:50 AM EST

whenever theres an Airshow, its always a Russian plane which spectacularly fucks up? Certainly seems to be the case in the UK, anyway.

Perhaps they should stick to something safer.

[ Parent ]

Lots of personal flying machine attempts. (5.00 / 1) (#3)
by bgalehouse on Wed Jun 12, 2002 at 02:21:06 AM EST

There is Mosier. His product changes every few years, his quest for investors has been going on for decades.

But a touch more seriously, I read about a Japanese fellow who designed a backpack helicoper around, basically, 8 little weedeater motors. Flew it (on a tether, as the FAA doesn't care what it is if it is low and tethered) at an American airshow, a few years back. I can't seem to find a definate reference to it on the web, though google shows up a few things which sound similar. I'm sure the write up is somewhere in my big pile of old aviation magazines. Kitplanes is hardly the epitome of conservative journalism, but they aren't Popular Mechanics.

It had a novel mechanical control system that made it flyable with a minimum of training. Not sure if the usual trick for landing without an engine would work though. 8 Engines give a lot of redundancy, it would come down gently with a few out, but failure modes like water in the gas give limits to the benefits of that redundancy. Even using 8 gas tanks, you presumably fill them from the same source at the same time.

There are emergency parachutes for more typical types of ultralight aircraft. He was trying to get one installed on it. Problem was that none of the parachute makers wanted to see their parachute on the thing.

Quite frankly, I think the real problem is social, not technical. Nobody wants the liability of selling one, or even of selling plans/kits. And I hate to think what the ATC system would need if they did become popular.

ATC and us (5.00 / 1) (#5)
by tftp on Wed Jun 12, 2002 at 02:42:53 AM EST

I hate to think what the ATC system would need if they did become popular.

Personal flying machines (such as this helicopter) don't have standard airplane electronics. Then every owner of the helicopter must own a GPS receiver which has all "forbidden zones" mapped. You carry the device with you in flight. If you stray into forbidden airspace (such as airport landing/takeoff path) the GPS receiver will buzz you and tell you how to get out of there.

I don't think ATC would be very concerned about low-flying (<300m) personal helicopters. There are very few airplanes so low, and you wouldn't want to climb too high because it only wastes your limited fuel. If any city/police helicopter pilot reads this, s/he can comment better, of course.

Sooner or later personal flying machines will become a fact of life, as cars did. There was fierce opposition to cars too, but it yielded to benefits that cars offered. The same will happen with helicopters, I am sure.

[ Parent ]

ATC (none / 0) (#64)
by phliar on Thu Jun 13, 2002 at 04:36:47 PM EST

Personal flying machines (such as this helicopter) don't have standard airplane electronics. Then every owner of the helicopter must own a GPS receiver which has all "forbidden zones" mapped.

I don't think ATC would be very concerned about low-flying (<300m) personal helicopters. There are very few airplanes so low

Please don't speculate about things you don't know anything about. There are aircraft with no electrical systems (I have flown them) that have no electronics. These aircraft often have unshielded ignition systems which makes even using a hand-held transceiver difficult. Any pilot that relies on electronics to navigate is just asking for trouble -- "the prudent navigator uses all available forms of navigation" (Bowditch). A current chart is essential and should be the primary form of navigation if you're not in the clouds. (Navigation by matching ground features to the chart is called pilotage.) Even among people that have GPS units, how many keep the database current and up to date? I know of no VFR pilots who are prepared to shell out cash every 56 days for database updates.

ATC may not be concerned, but other pilots -- both helicopter and fixed-wing -- will be, very much so. 300m (about 1000 feet) is not too low; in urban areas (like the San Francisco Bay Area) I often have to fly at heights of about 1000-1500 feet (300-400m) because of airspace restrictions.

To operate one of these things you will need instruction in navigation. You should be able tell with just your eyes when you're likely in airspace you shouldn't be in. (Of course you will also need instruction on how to operate the thing, and what you do when the engines fail.)


Faster, faster, until the thrill of...
[ Parent ]

Airspace confusion (none / 0) (#66)
by bgalehouse on Thu Jun 13, 2002 at 04:57:54 PM EST

Coupla points. Low is dangerous in aircraft - less time to deal with anything going wrong. Class E airspace covers most of the country starting at 1200 or 700 feet. There is no communication requirements, to fly in class E, but ATC has at least some interest. Near towered airports (within 5-30 miles) other sorts of airspace can appear, and can appear all the way to the surface. Many metropolitan areas are covered by these more restricted airspaces. I don't think you can fly around in, say, the bay area without clearance - no matter how low you are.

Add to the fact that these craft are small enough to not show up on civ radar (w/o a transponder, and at a modest distance, of course) and the nervousness people get about unauthorized airspace incursions since 9-11. A few months back, a cessna accidently flew too close to Camp David and was escorted to a military airstrip for questioning.

[ Parent ]

Japanese backpack heli (none / 0) (#6)
by NFW on Wed Jun 12, 2002 at 02:56:25 AM EST

Was it this one?


--
Got birds?


[ Parent ]

Probably. (none / 0) (#63)
by bgalehouse on Thu Jun 13, 2002 at 04:33:04 PM EST

Looks like it. Awfully similar in any case. An Oshkosh 99 demonstration is about the right timeframe. I'd say that is it, or a later revision of it.

[ Parent ]
video (none / 0) (#69)
by NFW on Thu Jun 13, 2002 at 05:20:43 PM EST

I just found an interesting (if breathless) video of same helicopter.

Mount a giant airbag under the landing gear, and a ballistic parachute above the rotor head, and I'd give it serious thought. :-)


--
Got birds?


[ Parent ]

Engine failures (none / 0) (#65)
by phliar on Thu Jun 13, 2002 at 04:46:52 PM EST

8 Engines give a lot of redundancy,
If one engine has a probability of failure of p, the probability of engine failure with 8 engines is 1 - (1-p)8. So if p is something like 1%, the combined probability is 8%.

What makes it even worse is that engine failures are not independent events. The most common cause of engine failure is the pilot -- more precisely, fuel exhaustion. It doesn't matter how reliable each engine is or how many you have. Sadly this is not even something that only "bad" pilots are susceptible to -- happens to everyone.


Faster, faster, until the thrill of...
[ Parent ]

failures and probabilities (none / 0) (#68)
by NFW on Thu Jun 13, 2002 at 05:17:03 PM EST

If one engine has a probability of failure of p, the probability of engine failure with 8 engines is 1 - (1-p)8. So if p is something like 1%, the combined probability is 8%.

That's not an 8% chance of a complete loss of power, though - it's an 8% chance of losing around 13% of your total power.

If you have (for example) a 25% safety margin, then losing one engine of eight is nowhere near as big a problem as losing your only engine.


--
Got birds?


[ Parent ]

Multi-engine redundancy (4.00 / 1) (#70)
by phliar on Thu Jun 13, 2002 at 09:10:57 PM EST

If you have (for example) a 25% safety margin, then losing one engine of eight is nowhere near as big a problem as losing your only engine.
Let me re-state that a bit: 8% chance of there being a problem. The old joke about twin-engine airplanes is "if one engine quits, the other carries you to the scene of the crash." Paradoxically, twins have an equal or worse safety record than singles. It is very easy to get distracted and forget about flying the airplane. (In spite of flight instructors yelling "fly the airplane!" at least once in every training flight!) Even airline pilots are not immune: in 1974, an Eastern Airlines L-1011 flew into the Everglades because all three members of the crew got distracted by a faulty landing gear indicator light. (CFIT -- controlled flight into terrain.)

I think the 25% number you wrote above is optimistic: most light twins have no or very marginal climb performance on one engine. The fact that eight engines were necessary for this thing probably indicates that you need at least seven working engines to maintain altitude. Add adverse weather conditions -- temperature in the 90s, humidity, airport elevation over 2,000 feet above MSL -- things go downhill very quickly.


Faster, faster, until the thrill of...
[ Parent ]

Yes, but (none / 0) (#79)
by bgalehouse on Tue Jul 16, 2002 at 03:11:55 PM EST

In a helicopter, a power shortage will cause it to drift down. Instead of needing a airstrip, all you need is a small flat area. It isn't the downward velocity that makes a poor landing into a crash, even without any engines in an airplane. It is the forward velocity.

So you have 8, well actually 4 engines, and if one of them goes out, you start drifting towards the ground. This is much less of a big deal, than losing an engine in a twin on takeoff.

This does nothing for water in the gas tank though.

[ Parent ]

This machine has one rotor. (4.66 / 3) (#8)
by i on Wed Jun 12, 2002 at 04:41:32 AM EST

One. Rotor.

One.

Where's the trick?

and we have a contradicton according to our assumptions and the factor theorem

The power's in the blades themselves... (none / 0) (#9)
by axxeman on Wed Jun 12, 2002 at 05:26:25 AM EST

In normal helicopter, power's in body, gets transferred to blades mechanically, action-reaction, body spins.

In this thing, rotor friction's the only force to cause the body to spin, and it would spin in the same direction as the rotor.

Feminism is an overcompensatory drama-queen club, with extra dykes. ---- Farq
[ Parent ]

Yes. (none / 0) (#10)
by i on Wed Jun 12, 2002 at 05:45:39 AM EST

But it would spin. You have to counter this somehow.

How do you do that without an additional motor?
Divert some energy from jets through blades to body?

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]

maybe (1.00 / 1) (#11)
by r1chard on Wed Jun 12, 2002 at 06:17:49 AM EST

it's a sort of powered autogyro, not really a chopper at all.

[ Parent ]
Huh? (none / 0) (#12)
by i on Wed Jun 12, 2002 at 06:33:38 AM EST

Autogyros have free-spinning rotors. Helis have powered rotors. This one has powered rotor.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]
Kinda (none / 0) (#74)
by phuzz on Sat Jun 15, 2002 at 08:22:59 AM EST

Helis have the power in the body trying to turn the axel of the rotor.  This has the pilot hanging from something that is spinning of it's own accord (scary image of man hanging from spinny rotors 500m up).  Technically it's closer to an autogyro than a helicoptor.  Also if you're moving the wind drag should help to counteract the friction in the bearings, maybe you could put a tail fin to help (a bit like a keel).

[ Parent ]
Easy trick (none / 0) (#27)
by dennis on Wed Jun 12, 2002 at 12:10:36 PM EST

Action/reaction. Normal helicopter, a motor spins the blades, and the reaction is the helicopter trying to spin the other way. This contraption, you have rockets at the end of the blades. The action is the rocket exhaust, the reaction is the blades spinning. That takes care of your conservation of momentum right there, so there's no additional force trying to push the helicopter around. The rotor's axis is just spinning free in its mounting.

[ Parent ]
There is an additional force. (none / 0) (#53)
by i on Thu Jun 13, 2002 at 07:29:52 AM EST

It's called "friction". It will rotate you in the same direction as the rotor.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]
Same as autogyros (none / 0) (#55)
by dennis on Thu Jun 13, 2002 at 09:00:41 AM EST

Yes, but with some good bearings that's a lot less than the torque in a normal helicopter, which rotates you in the opposite direction.

Autogyros would experience the same frictional force, and don't seem to have a problem with it.

[ Parent ]

Autogyros always fly forward. (none / 0) (#56)
by i on Thu Jun 13, 2002 at 09:24:10 AM EST

Vertical tail fins prevent them from rotating.

If you fly forward with this heli, the same will happen (if it has a tail fin, that is). If you hover, there's no stabilizing force, and you will start spinning. The longer you hover, the faster you will spin.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]

Good point (none / 0) (#59)
by dennis on Thu Jun 13, 2002 at 10:09:39 AM EST

Maybe there'd be a way to apply a counter-rotating force to counteract this. When you start to rotate with the rotor, a motor kicks in that pushes the rotor a little faster than it's already going, which pushes you back straight.

[ Parent ]
The amount of friction is small (none / 0) (#72)
by jforan on Fri Jun 14, 2002 at 10:43:15 AM EST

With greased ballbearings, the torque could probably be counteracted by air resistance.  Imagine hanging from a greased, quickly spinning, metal pole with the interconnect being a balbearing designed to minimize friction.  I don't think the torque would be that large.  It could certainly be countered with a small fan running off the power of the rotation (no large propellor would be necessary as in a helicopter).

A counter gyro would not work unless it continually accellerated.  (which would quickly become very dangerous.)

And finally, helicopters suffer two major effects that this design does not:  accelleration/decelleration of the propellor and wind resistance of the propellor.  In a vacuum, the first effect is still present.  Hovering in air, the second effect is present.

Jeff

I hops to be barley workin'.
[ Parent ]

parachutes? (1.50 / 2) (#15)
by squidinkcalligraphy on Wed Jun 12, 2002 at 07:10:32 AM EST

OK, so ur a few hundred (perhaps thousand) metres up in the air, and the damn rotor stops working. U want to jettison the damn thing as mentioned, and deploy ur parachute. The only problem now is gravity. The rotor will fall at the same speed as u do. this is a problem. u could _try_ to throw it sideways or down below you, but that would be damn tricky
An identity card is better that no identity at all
If the rotor still spins (3.50 / 2) (#17)
by i on Wed Jun 12, 2002 at 07:41:54 AM EST

just let the blades go. They will fly sideways.

If it doesn't spin, perform autorotation. This is a standard heli procedure of landing with engine shut down.

Or you may let the whole rotor assembly go. It will fall slowly (performing autorotation on its own) and you will fall fast. This gives you room to open a 'chute.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]

Parachute (5.00 / 1) (#22)
by jolly st nick on Wed Jun 12, 2002 at 09:24:14 AM EST

Other personal copter designs I've seen do not autorotate; I suspect this one does not either. There is just not enough rotational mass to keep the autorotation going for more than a few seconds.

One design I've seen packed a parachute in the hub and deployed it via an explosive charge. This seems a practical, if somewhat exciting solution. I would not want to be the person who tested this sysytem.

[ Parent ]

Just hypothetically... (none / 0) (#28)
by dennis on Wed Jun 12, 2002 at 12:18:00 PM EST

Having jet engines embedded in your blades might help the rotational mass. Might also increase drag too much, though.

[ Parent ]
autorotation and mass (none / 0) (#76)
by NFW on Wed Jun 19, 2002 at 08:26:11 PM EST

You don't need mass for autorotation, except at the very end, when you only need it for a few seconds. During the descent, the rotor is kept in motion by aerodynamics, not momentum - think of it like a windmill. In the last few seconds, you rely on momentum, but since the 'airframe' in this case weighs only sligtly more than the pilot alone, it would take very little energy as compared to a full-sized heli.

The real problem with autos and this backpack heli is that the rotor lacks in-flight "collective pitch" control. You can set the collective on the ground, to compensate for stuff like altitude and temperature, but you can't change the pitch in flight. This means the pilot can't change the rotor blades' pitch to get that windmill effect.


--
Got birds?


[ Parent ]

Until..... (none / 0) (#35)
by Trepalium on Wed Jun 12, 2002 at 02:19:09 PM EST

That may all work, until you pulled the chute, and the rotor that was above you starts falling faster than you, and plumets through your chute. I don't think you really want that kind of debris in the air with you, while you're trying to touch down safely on the ground. The safest approach is to find some way to integrate both devices together in a way they can't conflict with each other.

[ Parent ]
Parachutes (none / 0) (#38)
by mmealman on Wed Jun 12, 2002 at 04:01:56 PM EST

Well, first off the rotor won't fall at the same rate as the person flying it. They're aerodynamically different. And then even if it did the odds are low it'd tangle with a deploying parachute, at least if you used a round chute. One problem with using a parachute is that the FAA mandates that reserve parachutes be repacked by a licensed rigger every 120 days. So you'd basically have to take your copter to a rigger and pony out 50 bucks for a repack every 4 months.

[ Parent ]
I see a similarity here... (none / 0) (#44)
by tftp on Wed Jun 12, 2002 at 08:09:15 PM EST

So you'd basically have to take your copter to a rigger and pony out 50 bucks for a repack every 4 months

Most people have to take their cars to a gas station and pony out 50 bucks every couple of weeks ;-)

[ Parent ]

Yeah, right... (3.00 / 1) (#16)
by J'raxis on Wed Jun 12, 2002 at 07:23:03 AM EST

Drunk drivers, idiots with cell phones ... can’t even properly handle driving in two dimensions, how well do you think they’d handle three?

— The Raxis

[ J’raxis·Com | Liberty in your lifetime ]

Rotary Rocket (4.00 / 1) (#29)
by dennis on Wed Jun 12, 2002 at 12:27:24 PM EST

This is the same concept as Rotary Rocket's original Roton design, an attempt at a single-stage-to-orbit vehicle. They originally had rockets at the end of their rotor blades, which rotate to point downwards as the vehicle leaves the atmosphere. The use of centrifugal force instead of fuel pumps was a big weight savings.

The design was changed, with a more traditional rocket and autorotating blades for descent. At one point they talked about spinning the base so they still didn't have pumps, not sure if that's what they settled on. Unfortunately, they ran out of money, the project's dead now.

Al Quaida (2.33 / 3) (#31)
by drquick on Wed Jun 12, 2002 at 12:32:10 PM EST

This would be excellent for Al Quaida. Even if from a somewhat shallow Hollywood perspective. Imagine flying in to the white house lawn during press conference and then blowing one self up after saying "Take this you infidel dog!" *BooM*

you'd probably be shot before you blew up [nt] (none / 0) (#39)
by damiam on Wed Jun 12, 2002 at 04:09:37 PM EST



[ Parent ]
BOOM (none / 0) (#77)
by maozo on Mon Jun 24, 2002 at 12:02:21 PM EST

Ok so he'll explode AFTER you shoot him.

[ Parent ]
I don't like the idea (4.00 / 1) (#33)
by hovil on Wed Jun 12, 2002 at 01:51:29 PM EST

If these 'backpack choppers' become mass-producable, cheap and reliable, I would urge my government to ban them, or at the minimum limit their use to farm   / rural work. The potential for some drunken fool to come flying into me with one of these things while I'm on my morning run is too great, and I'd rather keep traffic on the ground where the worst most people have to endure is a fender bender, rather than having their torso cut in half by a rotor blade when someone comes too close to you.
It may be a fun idea of the future, but the stupidity of humans seems to defeat most of the gadgets seen in The Jetsons and other futurisitc fiction from being useable on a society-wide level.

Not that I think you're wrong, but... (none / 0) (#46)
by Gwen on Wed Jun 12, 2002 at 08:40:30 PM EST

Couldn't you put a wire basket type thing over the blades to keep them from cutting stuff? I don't think it would obstruct airflow at all.

--
"So raise your hands in the air like you're born again
But make a fist for the struggle we was born to win"
-The Coup ft. Dead Prez, Get Up!


[ Parent ]
Blade protector (none / 0) (#47)
by tftp on Wed Jun 12, 2002 at 09:10:33 PM EST

Couldn't you put a wire basket type thing over the blades to keep them from cutting stuff?

Sure you can. The article describes a portable machine, for soldiers, where the size is everything and the danger is irrelevant. When this helicopter is sold to public, then the safety will be increased at cost of portability, size and a little of weight (and performance). I will gladly exchange extra 2% of range to extra 80% of safety.

[ Parent ]

like heck (none / 0) (#54)
by streetlawyer on Thu Jun 13, 2002 at 07:46:52 AM EST

The article describes a portable machine, for soldiers, where the size is everything and the danger is irrelevant

Wot, so the army doesn't care about soldiers being in danger from their own equipment? Interesting new tactical theory you have there, Herr Clausewitz.

In fact, the problems in using this in a military context are probably even greater than in civilian contexts, because you don't tend to be wanting just a few soldiers in any given place; anywhere you want to have soliders at all, you want to have at least a dozen.

It strikes me that the reason this thing doesn't have any safety precautions is that it can't be made safe. I would further surmise that this is why we aren't seeing armies of helitroops being set up anywhere at the moment.

--
Just because things have been nonergodic so far, doesn't mean that they'll be nonergodic forever
[ Parent ]

and "safe" means what? (none / 0) (#75)
by joto on Sun Jun 16, 2002 at 05:47:20 PM EST

Nothing can be made "safe". Car's certainly aren't. Yet they are continually being made "safer", we have seat-belts and air-bags, coachworks designed for absorbing an impact, brakes that will not block any wheels, legal requirements for maneuverability and control, drivers licenses, signal lights, mirrors, etc...

Just because this device doesn't have any safety-enhancements doesn't mean that such enhancements wouldn't be useful. It simply means that this is still not a consumer device, it is research, and possible first adopters could be the russian military (if they are interested).

There are lots of enhancements that could be made to make this device safer. Of course, some of them will make it into something else (e.g. adding a cockpit, a car is also safer than a motorcycle).

But I do agree that it is hard to see what kind of military applications this thing would have. The idea of the military is to build up an efficient organization around specialization. Need air-transport? Fine, call them up on the radio! There's no need to carry around your own helicopter. Need reconnaisance? Fine, use satellite photos, high-altitude airplaines, light unmanned vehicles, etc.

And of course there are other drawbacks. A soldier with full gear (backpack, guns and ammo, etc...) is going to be much heavier than an average man without gear, so the question of payload is interesting. Is it sturdy enough to be packed and carried around without constant attention to damage? Does it require lots of maintenance and care? And of course, is it reasonably safe to use?

I would still love to try one for recreational flying though...

[ Parent ]

This reminds me... (5.00 / 1) (#34)
by toganet on Wed Jun 12, 2002 at 01:54:44 PM EST

Of that old ATARI game H.E.R.O (Helicopter Emergency Rescue Operations).

Anyone else remember that?

Johnson's law: Systems resemble the organizations that create them.


dude! (5.00 / 1) (#36)
by jbridge21 on Wed Jun 12, 2002 at 03:18:00 PM EST

That was the best game ever! It was really cool to have the three ways to orient the thing and go flying around shooting the bad guys and picking up hostages...

[ Parent ]
It's The Confusing (none / 0) (#48)
by Holloway on Thu Jun 13, 2002 at 01:46:17 AM EST

Are we talking about Choplifter here?


== Human's wear pants, if they don't wear pants they stand out in a crowd. But if a monkey didn't wear pants it would be anonymous

[ Parent ]
yea (none / 0) (#40)
by Wah on Wed Jun 12, 2002 at 04:16:10 PM EST

I played it on a Commodore 64 though.
--
Fail to Obey?
[ Parent ]
No, more like XEvil (none / 0) (#41)
by pin0cchio on Wed Jun 12, 2002 at 05:17:19 PM EST

I've never played HERO, but I have played XEvil, an open-source side-scrolling deathmatch game for UNIX and Windows. The "good guy" seems to be the chopper boy.
lj65
[ Parent ]
H2O2 Unsafe? (none / 0) (#37)
by aero6dof on Wed Jun 12, 2002 at 03:45:43 PM EST

I'm confused, I thought it was pretty safe stuff. Even the link you provided describes it as "a powerful yet versatile oxidant that is both safe and effective."

Look at the concentration... (4.00 / 2) (#42)
by gnovos on Wed Jun 12, 2002 at 05:46:15 PM EST

It is safe to humans when in .02% concentrations or whatever that you find at walgreens.  But when it's 80% or 90% pure, it will happy eat a hole right through you.  It will break down into water and oxygen, sure, but before it does, a can of it exploding in your face it will turn you into genetic slush in no time fast.

A Haiku: "fuck you fuck you fuck/you fuck you fuck you fuck you/fuck you fuck you snow" - JChen
[ Parent ]
HMS Explorer (4.50 / 2) (#49)
by Nimey on Thu Jun 13, 2002 at 02:04:20 AM EST

Look up the story of HMS Explorer, a British submarine that used hydrogen peroxide for fuel right after World War II. Apparently the stuff can be explosive when concentrated.
--
Never mind, it was just the dog cumming -- jandev
You Sir, are an Ignorant Motherfucker. -- Crawford
I am arguably too manic to do that. -- Crawford
I already fuck my mother -- trane
Nimey is right -- Blastard
i am in complete agreement with Nimey -- i am a pretty big deal

[ Parent ]
Fuel that sank Kursk submarine? (3.00 / 1) (#71)
by Respectfully on Fri Jun 14, 2002 at 08:58:48 AM EST

Do a search on Google using the following terms: kursk hydrogen peroxide 2002 Respectfully

[ Parent ]
No FAA approval Necessary (4.80 / 5) (#43)
by FlightTest on Wed Jun 12, 2002 at 06:22:47 PM EST

To the posters saying the FAA would never approve it, they don't have to. You only have to have FAA approval to fly in controlled airspace, or over any assemblage of people. Which for most of the U.S., means you can kill yourself with this thing as long as you stay under 1200 feet above ground, away from other people. Ultralights, for example, aren't FAA approved. Of course, you can't fly them over populated areas, either.

Of course, if you wanted to use it in the city, you'd have to get FAA approval, which you'd never get, not because of "terrorism" but because the thing is basically unsafe to fly over the unsuspecting public and cannot be made safe. See, the FAA could care less if you wish to kill yourself in some contraption. But you have to demonstrate the ability to land safely in the event of powerplant failure to fly over other people. And that includes not killing anyone with parts from your aircraft. The FAA would never allow you to jettison the blades in a certified version, because they will come to earth somewhere. An uncertified version can of course jettison the blades, because you're not supposed to be flying over anyone.

This is a neat toy. Take out, fly around the barn at 20', land, put it away until the next time to show off. But not at all useful for anything.

Why did I flip? I got tired of coming up with last minute desparate solutions to impossible problems created by other fucking people.

Solutions are easy (none / 0) (#45)
by tftp on Wed Jun 12, 2002 at 08:21:21 PM EST

But you have to demonstrate the ability to land safely in the event of powerplant failure to fly over other people

Well, I am not a mechanical engineer, but even I can see lots of viable solutions to this problem:

  • jettison blades but keep them tethered
  • do not jettison blades but fold them upward
  • flip the blades vertically (attack angle 90°)
  • break blades into many small pieces (Harrier)
It can be done. The easiest solution, of course, is to mount the parachute above the blades; this way blades can't cut into the ropes, and you don't need to jump - you'd float to the ground at a reasonably comfortable speed, and likely won't be injured. The thing can be made very safe.

[ Parent ]
Not viable (4.33 / 3) (#61)
by FlightTest on Thu Jun 13, 2002 at 12:05:08 PM EST

The folding (option 2) or feathering (option 2) solutions are not viable because the mechanism to do that alone would be exceedingly heavy. I really don't think you could make the teathering idea work. Not and ever be able to use the thing again at least. I really doubt you'd ever get approval to have enough explosive to break the blades up finely enough to keep them from hurting anyone. It would take a lot to insure there were no large pieces.

Mounting the parachute above is really the only option, but you would have to prove that deloying it in any flight regime would be safe in case of accidental deployment. So it would have to work at max forward speed as well.

There's a lot of other reasons you'd never get FAA approval and therefore never be able to fly it in the city. You'd never demonstrate crash survivablity, which would be required. You'd probably never be able to show certifiable handling characteristics. Many homebuilt aircraft, even though they are "good", are not certifiable because of poor handling characteristics in one flight regime or another. Typically, stick forces are too light. The rotors would have to pass some variation of the chicken test. At 20 kg all up weight, I'll bet the blades could never stand a bird strike with a sparrow.

The article is long on hype, short on details. A lot of it makes absolutely no sense at all, which I'll be generous and chalk up to poor translation, though you'd think Pravda could afford good translators. In all, it reads like a sixth grader made the whole thing up.

Why did I flip? I got tired of coming up with last minute desparate solutions to impossible problems created by other fucking people.
[ Parent ]

Sorry, this won't work (4.50 / 2) (#62)
by dimrrr on Thu Jun 13, 2002 at 12:20:40 PM EST

I'm no mechanical engineer either, but basic physics tells me not all of these approaches are really feasible.
  • jettison blades but keep them tethered: just imagine two tethered blades flying around you at hundreds of mph (typical speed of the rotor blade tips)
  • do not jettison blades but fold them upward: the centrifugal force won't let you do that until the rotor stops. This force is many times more than the weight of the heli. Imagine the heli sitting on the ground with its rotor stopped. Imagine a crane that tries to pick it up using the lines attached to the blade tips. What will happen? The rotor blades will snap. When rotor is at normal rpm the centrifugal force pulls the blades apart so much that a heli in the middle behaves like a piece of underwear hanging on a clothesline. Look up "coning angle" for details.
  • flip the blades vertically (attack angle 90)... better just set attack angle to zero and let them rotate. Which still leaves you with no lift.
  • break blades into many small pieces (Harrier)... so that more people get hurt?
And the parachute won't work either no matter where it's mounted because the thing is _designed_ to fly low and/or close to the obstacles. You need at least 100 meters of altitude for the chute to open and even that is really pushing it.

[ Parent ]
FAR Part 103 (5.00 / 2) (#67)
by phliar on Thu Jun 13, 2002 at 05:04:07 PM EST

To the posters saying the FAA would never approve it, they don't have to. You only have to have FAA approval to fly in controlled airspace, or over any assemblage of people. ... Ultralights, for example, aren't FAA approved. Of course, you can't fly them over populated areas, either.
Anyone that wants to read it, the appropriate regulation (in the US) is FAR Part 103. The contraption needs to weighs less than 254 pounds and can't have a fuel capacity more than 5 gallons. (It can't be capable of going more than 55 knots either but I doubt that will be a problem for this thing.)


Faster, faster, until the thrill of...
[ Parent ]

Dual fuel system (5.00 / 2) (#50)
by Nimey on Thu Jun 13, 2002 at 02:10:39 AM EST

jets at the ends of blades use the fuel that consists of two components; if true, this would be a key difference because these components can be safer, and maybe even easy to maintain.
Keeping the two fuel components separate is not a guarantee of safety. For further enlightenment, look up data on the Messerschmitt Me 163B Komet rocket-powered interceptor. It used a 2-component fuel system[1], but was prone to random explosions if the aircraft was subjected to even a slight shock or if the plumbing leaked.

[1] Called C-stoff and T-stoff, IIRC.
--
Never mind, it was just the dog cumming -- jandev
You Sir, are an Ignorant Motherfucker. -- Crawford
I am arguably too manic to do that. -- Crawford
I already fuck my mother -- trane
Nimey is right -- Blastard
i am in complete agreement with Nimey -- i am a pretty big deal

One of those was H2O2. (4.00 / 1) (#51)
by BobRobertson on Thu Jun 13, 2002 at 02:17:57 AM EST

One of those, the C-Stuff or the T-Stuff, was in fact hydrogen peroxide. I cannot remembe what the other stuff was.

Both corrosive, both toxic, both volitile. Not fun.

This same concept was used in the American Titan missile system. Two fuels, both some kind of nitrogen compound I believe, mix and burn. Both toxic, both volitile.

Back in the late 70's, a technician dropped a socket wrench bit in a Titan missile silo. The socket bounced off the concrete floor, and punctured the fuel tank. Evacuation time!

Oxygen and Hydrogen seem so benign in comparison!

Bob-
September 11, 2001. The most successful day for gun control and central planning in American history.
[ Parent ]

C-Stoff, T-Stoff (5.00 / 2) (#58)
by Nimey on Thu Jun 13, 2002 at 10:05:54 AM EST

According to <http://www.warbirdsresourcegroup.org/LRG/fuels.html>:

C-Stoff - Catalyst (30% hydrazine hydrate, 57% methanol and 13% water) used by Walter R ii-211/HWK 509A rocket motor

T-Stoff - Rocket Fuel comprising 80% hydrogen peroxide plus oxyquinoline or phosphate as a stabilizer
--
Never mind, it was just the dog cumming -- jandev
You Sir, are an Ignorant Motherfucker. -- Crawford
I am arguably too manic to do that. -- Crawford
I already fuck my mother -- trane
Nimey is right -- Blastard
i am in complete agreement with Nimey -- i am a pretty big deal

[ Parent ]

Those two nitrogen-based fuels (none / 0) (#73)
by mduell on Fri Jun 14, 2002 at 08:30:15 PM EST

This same concept was used in the American Titan missile system. Two fuels, both some kind of nitrogen compound I believe, mix and burn. Both toxic, both volitile.

Probably hydrazine (N2H4) and nitrogen tetroxide (N204). Mark Duell

[ Parent ]
In addition. (none / 0) (#52)
by i on Thu Jun 13, 2002 at 07:25:15 AM EST

This particular design is not a dual fuel system at all. It is multi-fuel (can use many kinds of fuel, one at a time). Great for military.

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]
Easy to fly? I don't think so. (4.00 / 1) (#57)
by dimrrr on Thu Jun 13, 2002 at 10:04:22 AM EST

Flying helicopters is anything but easy. If you don't believe me, try any decent simulator like RealFlight Deluxe G2. Even without the wind with 5 controls to think about and no brakes it takes just a few seconds to totally lose control and crash.

It's true that if the engine quits you can autorotate, but only if you happen to be on the right side of the dead man's curve (in other words, there are certain combinations of airspeed and altitude that do not allow you to autorotate safely). And the rate of descent during autorotation is so much higher that if you make one mistake at the last moment your landing gear (in this case feet) will snap. Having 20kg on your back and rotating blades just over your head do not make this any easier.

While definitely a technological marvel, this thing was designed for special ops, not regular folks. I guess neither safety nor ease of use was high on the list of priorities.

I meant Hollywood (none / 0) (#78)
by drquick on Mon Jul 01, 2002 at 03:52:30 PM EST

The suggestion was from a Hollywood perspective. I was just joking. I mentioned Hollywood a bit ambiguously there.

Another backpack helicopter | 79 comments (69 topical, 10 editorial, 0 hidden)
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