Rocket Men

theodp writes "Slate reports on the guys who really, really want to fly, who got together the other week at the Niagara Aerospace Museum for the First International Rocketbelt Convention. To date, only 11 men in history have free-flown a rocketbelt (aka JetPack). More men have walked on the moon. Why? 'It's not a matter of if you get hurt, it's when,' says Eric Scott, an ex-stuntman who's in the exclusive club."

Comments

The 1970's Jet Pack...

[__aaclcg7560]

Whatever happened the jet pack technology that NASA was working on back in the 1970's? Saw it on the "Six Million Dollar Man" TV show.

Re:The 1970's Jet Pack...

[Fullhazard]

They figured out that something that's expensive, dangerous, incredibly loud, only provides 30 seconds of thrust at best, and weighs about 100 pounds isn't a very good military tool. Go figure, right?

Re:And this is different from

[Itninja]

I guess the big difference is that if you bite it boarding, you might get seriously hurt. With an outside chance of death. Whereas, if your 150ft in the air, travelling at 25mph, and your jetpack decides to crap out.... there would only be an outside chance of NOT becoming a mangled corpse.

Re:And this is different from

[Thisfox]

Well, for a start, you are much less likely to run out of fuel 18 metres up in the air while on a skateboard...

Re:the guidence system runs Linux

[Solra Bizna]

... until it is linux will stay with >1% marketshare.

Wait, remind me why that's a bad thing?

Or did you mean '<'? ;)

-:sigma.SB

Gyroscopic stabilizers

[Anonymous Coward]

These people need computer-controlled gyroscopic stabilizers. A fly-by-wire system could dramatically improve the safety of rocketbelts. No doubt that would make them much more popular.

Re:Gyroscopic stabilizers

[kimvette]

That is not the only problem; other problems include fuel capacity (range) and thermal management. I would love, repeat, LOVE to fly one of those, but a homebuilt high-performance jet aircraft (like Viperjet) or even someday a homebuilt spacecraft would be more fun, IMHO.

Re:Gyroscopic stabilizers

[evanbd]

And while we're at it, that's a *hell* of a lot easier said than done. You can't do it on cheap gyros (read: you're probably spending $5-10k per axis), and they're not particularly light weight (a couple pounds each may not seem like much, but it eats into your fuel budget quite quickly). And you need a *good* control program, which isn't easy to write. Getting it mostly right wouldn't be too hard, but would you trust your safety to "mostly right"? To date, only one VTVL rocket vehicle has demonstrated fully autonomous takeoff, hover, and landing (John Carmack's vehicle over at Armadillo Aerospace). It ain't easy.

Also, don't forget you have to build the rocket motors and feed system and such. Most belts so far are peroxide monopropellants -- a good choice IMHO, but peroxide is hard to get and takes a lot of care to handle safely. And building any size rocket motor and ensuring it's safe enough to stand next to is a bit of work.

What I'm saying is, if you're a single amateur, or a small group, then building just the rockets is a big project unto itself. It shouldn't surprise you that no one has the time, money, and skills to do that, *plus* build and test the IMU, *plus* write fly-by-wire control software for it. If a modest sized startup company decided to pursue the matter, with a bit of financial backing, I would expect they could get it all built without too much hassle (provided they had the appropriate expertise in all areas, obviously). Oh, and don't forget that your software has to handle a non-fixed CG if the person moves about much at all.

Re:Gyroscopic stabilizers

[jcr]

You can't do it on cheap gyros (read: you're probably spending $5-10k per axis),

Why not? There are gyros that model helicopters use that are cheaper than $100, and an RC chopper is a whole lot twitchier than something with the mass of a human being in it. If your flight only lasts for a couple of minutes, then you hardly need high-precision gyros that won't drift more than a degree per hour.

-jcr

Re:Gyroscopic stabilizers

[evanbd]

Hmm. I don't know how good those gyros are; I was of the impression that there wasn't really a whole lot between the cheap sensor grade stuff and the good navigation grade fiber optic ones. Also, AIUI the differences aren't just in drift rate, but also in things like vibration sensitivity and cross-axis coupling.

I suppose you could use the inexpensive ones, as long as your goal was to change the pilot requirement from "top of the line test pilot" to "very good helicopter pilot," and not an attempt to make it flyable by anyone with a bit of simulator practice.

You might do an ok job if the gyros just tried to hold the spin *rate* to zero, and let the pilot handle leveling the vehicle; one fewer integral makes for much slower error growth.

Re:Gyroscopic stabilizers

[e2d2]

This is true, gyros are used to control autonomous vehicles in 3d spaces, specifically using IMUs with multiple gyros on flying vehicles. I'm working on one myself and it's taken years of effort so far, there is a small community of UAV builders that all work to achieve the same goals. So it is possible.

But I wanted to point out that the parent brought up a good point about accuracy. The simple fact is you can't get around the inherent error in such sensors over time. For example, if we have one gyro just measuring one plane and we bank the aircraft into a long slow turn. Any person or device in the aircraft will, in a perfect turn, feel the force of "gravity" coming from directly below, yet the aircraft is most certainly not flying straight. The only way to compensate is to use a filter and combine the IMU sensor data with other types of sensors such as optical, gps, dead reckoning using a compass and a clock, etc. Anything helps to assist, but correction seems to be necessary.

But then you have the added weight of such sensors and the platform weight goes up. You try to compensate this with a larger powerplant and again you get added weight and size. The larger sensors use more power and require larger batteries. It's a balancing act.

The reason we don't see palm sized autonomous vehicles with highly accurate navigation is because of the current size and weight of the sensor packages. That's why new techniques such as using optical flow with a small CCD are so important, for the inherent reduction of weight and power usage.

Re:Gyroscopic stabilizers

[evanbd]

Not entirely true. I have spoken with multiple people directly involved in the area -- gyro-based IMUs for rocket vehicles -- and the FOGs are clearly superior. AIUI, some of the recent MEMS gyros *might* be good enough for low-accuracy use, depending on the application details, and how much other sensor data is available to correct with.

I do know that at least until recently, inexpensive gyros were completely unusable. Modern ones appear better, but my sources suggest that they aren't all the way there yet. It's possible there are good gyros out there that haven't been tried in this application and that I haven't heard about; I'm not averse to admitting my knowledge could be out of date or incomplete. I am, however, quite confident that the problem is not so easy as the OP implied.

And for reference, IAARS, and I have read detailed discussions by people doing actual investigation with real hardware testing of exactly this problem -- and I'd say that makes me better qualified to comment than the vast majority of posters. But, like I said, not infallible -- so please don't jump on me for admitting my fallibility.

Re:Gyroscopic stabilizers

[wjsteele]

To date, only one VTVL rocket vehicle has demonstrated fully autonomous takeoff, hover, and landing (John Carmack's vehicle over at Armadillo Aerospace).

I'm not sure they've actually conducted a fullly autonomous test. According to their web site, they've only done very limited tethered tests.

However, I know the Delta Clipper (DC-X) and it's follow on (DC-XA) had several sucuessful tests, fully autonomous. But even they had a bunch of development issues that eventually lead to the programs cancellation.

Bill

Duff Man!

[LiquidCoooled]

Theres a guy who flies these jetpacks called the GoFast Rocketman.
hes sponsored by the Go Fast Sports and Beverage Co.

I wonder if he can do the pelvic thrust and Heuuugh?

The link I pointed to contains a movie of him in action (and other stuff).

Re:And this is different from

[Excen]

Well, for a start, you are much less likely to run out of fuel 18 metres up in the air while on a skateboard...

What? You mean those Mountain Dew commercials aren't accurate representations of the sport of skateboarding?

rocket "belt"

[macadamia_harold]

Why is it called a rocket "Belt", when it's typically something the size of a surfboard with a pair of propane tanks that you strap on your back?

Re:rocket "belt"

[garcia]

Why is it called a rocket "Belt", when it's typically something the size of a surfboard with a pair of propane tanks that you strap on your back?
--
#11. No pirate shall ever wear a "fanny pack".

Well, I think your .sig has answered that for us!

Re:rocket "belt"

[Hangin10]

This part of it I don't understand. I can understand being strapped to it, but why should the human have to support it? Why not have "_|"-shaped (excuse the ASCII-art excursion) bars under the arms and up over the chest/shoulder area with the human ON the device (like a flying Segway, just not quite so white and nerdy). This probably changes the whole concept, but I'd rather get into what I described rather than strap a rocket to my back. Strapping a rocket to one's back seems rather ill-advised in a rather distinctly "Acme" fashion...

Re:rocket "belt"

[westlake]

Why is it called a rocket "Belt", when it's typically something the size of a surfboard with a pair of propane tanks that you strap on your back?

The rocket belt made its first appearance in comic strips like Flash Gordon around 1934. It is everyone's evokes dream of someday flying like a bird, without the need for magic.

How many people have flown a jetpack?

[Brad1138]

To date, only 11 men in history have free-flown a rocketbelt (aka JetPack)

Make that 12, your forgetting Duke Nukem.

Re:Oblig etc.

[TubeSteak]

(Since this is /.)
In fact, forget the rocket belt and the blackjack.

Sounds like a job for real-time computers

[dpbsmith]

It's understandable that in 1961 the pilot needed to fly the rocket belt with only his own reflexes and semicircular canals to guide him.

But even in the late 1960s my aero-and-astro student colleagues told me that even the Boeing 727 was too unstable to be controlled by a human pilot using reflexes alone: it relied on "yaw dampers," servo mechanisms that amounted to electronic analog computers, to tame the raw behavior of the plane.

The Boeing 777 is a completely "fly-by-wire" design.

It seems to me that it ought to be possible to design microprocessor-controlled rocket belts that would be much easier and safer to fly than those of the 1960s. (Including, of course, electronic active noise cancellation in the helmet to provide at least some reduction of the "deafening noise 3 feet three feet from his ear."

Trying to fly the rocket belts described in the strikes me as rather like trying to fly a full-size, exact model of Langley's Aerodrome. It may be possible--for someone with the reflexes of a Santos-Dumont and the nerves of an Evel Knievel--but it's still just a stunt. The Wright Brothers achievement was ''not'' building an aeroplane that could get off the ground; it was building an aeroplane that they ''and others'' could get (relatively!) ''safely'' off the ground.

Re:Sounds like a job for real-time computers

[GeeksHaveFeelings]

The Wright Brothers achievement was ''not'' building an aeroplane that could get off the ground; it was building an aeroplane that they ''and others'' could get (relatively!) ''safely'' off the ground.

What? Their first airplanes were insanely unstable. It was harder to control than a F/A-22 now, except the F/A-22 has a powerful computer to keep it stable. It had next to no dihedral and its horizontal stabilizer was in front of the plane, while the vertical stab had next to no moment (so it was pretty useless, though better than nothing). They could pilot it because they had practised on equally unstable unpowered gliders for years. What they achieved was a new, working model of aerodynamics (as nothing had existed at the time for propeller design and the existing knowledge about wings were wrong), a light, high-powered gasoline engine, and an airplane that could get off the ground and was cheap. It was however, not at all safe or even remotely pilotable by modern standards.

What about women?

[Dan East]

To date, only 11 men in history have free-flown a rocketbelt (aka JetPack).

According to the Wikipedia article, at least one woman (Isabel Lozano) has flown one as well (happened almost a month ago).

As to why haven't more people flown the device, take a look at Isabel's pictures, and you'll see that had to make a custom cast of her body for the mounting hardware the device uses. Also, for some reason many people may not feel very comfortable with jets of gas at 740 C venting at supersonic velocities mere inches from their body.

Dan East

Re:What about women?

[Steve Newall]

While impressive, Isabel's flight was not "free-flown" and does not count towords the list.

On the Fringe

[tb3]

The (strange/interesting/sad) part of this story is how far out the people involved are. I noticed there was no mention, either in the Slate article or the actual convention website, of these guys who claim to have the only functional rocket belt in existence. Then there's Juan Manuel Lozano, the Mexican inventor who claims to developed a break-through method for creating the 90%-pure hydrogen peroxide fuel needed for the rocket belt.

And then there's the whole RB2000 saga, which involved fraud, murder, and the disappearance of the only prototype. The full story can be found on the rocketbelt.nl site. Rocketbelt developers are out there on the edges with the ufologists, perpetual motion researchers, and free energy salesman, with the exception that rocketbelts can actually work!

The Alternative?

[webword]

Very light jets!

2006: The year of the very light jet

Very Light Jet Magazine

The Light Jet Age

OK, so they are a $1-2 million. That's a lot of money. From what I've read, however, these jet packs aren't that cheap either. (They're not mass produced so the price hasn't dropped at all.) If you bought part of a jet as a time share, with say 20-50 other people, the price drops significantly. It is a viable option for some people.

Undocumented

[Tablizer]

To date, only 11 men in history have free-flown a rocket-pack

I take it this excludes burrito dinner + sparks accidents?