When Raymond Li decided to build a jetpack propelled by water instead of rocket fuel, most of his friends thought he had gone crazy. Worse, engineers told him it would be impossible to manage the water's mass and thrust to keep it stable in the air.
It took four prototypes and more than 200 flight tests to get it right. But now, with a mere 30-pound pack, the Jetlev-Flyer is almost ready for production, generating 430 pounds of thrust and letting Li fly forward at 22 mph up to three stories high. His next unit will get up to 35 mph. Want one? Late this year, the craft will go on sale—just be ready to dish out close to 130 grand.
How the Jetlev-Flyer Works
Li built the backrest out of fiberglass, glued a thick layer of rubber foam to the front so it wouldn't sink when he takes off and lands, and attached a four-point racecar-style harness to lock himself in. He also added a crotch belt, a unicycle-like seat and an acrobat's trapeze for a footrest; all help to keep the operator in optimal flying position.
Li custom-built the first boat unit out of plywood and fiberglass, but his latest prototype is an extensively modified Jet-Ski with a 215-horsepower engine, which powers an onboard pump attached to it by a direct-drive shaft. The pump connects to a 33-foot-long, four-inch-diameter polyester-and-rubber hose. The production craft, a smaller and lighter pod, will come with a 260hp engine.
The Y-shaped assembly on the back, as well as the jet nozzles and the handlebars that steer them, are custom-fabricated aluminum tubes. Li attached the assembly to the harness above the body's center of gravity so that, in flight, the operator is suspended beneath it. He takes off from the water, hits a trigger on the handgrip to start the pump on the pod behind him, turns the throttle, and two streams of high-velocity water of up to 60 psi lift him as high as 30 feet in the air. To go forward, he pushes down slightly on the handlebars, angling the nozzles to a maximum of 45 degrees.
The H2Whoa Credo: DIY Can Be Dangerous
We review all our projects before publishing them, but ultimately your safety is your responsibility. Always wear protective gear, take proper safety precautions, and follow all laws and regulations.
Wow! That's pretty impressive execution of creative ways to get airborn from sea. I wonder if he can turn from left to right, or it just goes straight?
All he needs now to go with his Boba Fett jetpack is a starship speedboat:
WHAT B.S.!!!! WATER-POWERED?!?!?!? And the water just pumps itself? I guess we can call fire trucks water-powered as well, eh? And air compressors are "air powered." Now THAT would be a story.
scghkl, read the details of the story and do a little more research you will see that it's not BS and how this works. The picture above, unfortunately, hides the trailing hose that connects to the pump that trails along behind you in the water. There are online videos of it in operation. Looks like a lot of fun just too bad it's so expensive. Other articles have suggested it will be available to rent at world resorts.
i bet you could make only a few modifications and be able to sell this to coastal fire departments for shipboard fires. you would have to protect the operator from the heat and steam generated below, or add another nozzle for auxiliary use, but piloting for balance with three thrust vectors while trying to put out a fire might be a little too much to ask.
Make a remote controlled octagonal shaped unit with nozzles on top, bottom, sides and front. Firefighter can steer unit at safe distance.
TOO DAMNED EXPENSIVE!! Not very practical since it is not self contained.
Time to go back to the drawing board, Raymond.
Very, very cool !!!
Expensive yes but he will sell some of these for sure.
My only problem with this design is that it is limited in operational scope as a hose is hooked up to it. You couldn't travel with it if you wanted to.
Still very impressive though. He can go to all the naysayers and yell "NOW WHO'S LAUGHING!"
BTW, JamesDonVito. If you have not had a chance to do it. Check out the video. You can maneuver this thing around like a conventional jetpack (No disrespect, just helping you out; people over the internet these days tend to be touchy about people addressing them).
"Welcome! to the Federation Starship SS Buttcrack!!!"
I should so find out how to build one of those.
I am surprised the pressure is so low and the hose is so big. I would have thought a higher pressure would have allowed him to use way less water by accelerating it more. This would reduce the flow rate and the size of the hose. A 4 inch hose is a monster. A smaller hose would also allow it to go higher, because it would weight so much less per linear foot.
I take it the drag behind boat follows you around the lake. This makes is sorta like watersking, or jetsking, which has a large following, so I GUESS there's a potential market. When it is priced like a jetski + $1000 it will sell somewhat, assuming it is not as dangerous as it looks. The fact that it is always over water will help until some yutts tries to land it on a marina dock
It is a novelty. Since you can't really go anywhere it is just a Seaworld sideshow. It is not the answer to the question, "Hey Dude, where's my jetpack?"
Thats a quick way to get high in a building that is on fire as well as put some of the fire out!
You people really need to read the WHOLE article before posting dumb comments like "WATER POWERED???". The article obviously states that it's powered by a modified jet ski. And you can travel with it, just put the "boat" that contains the pump on a trailer and take it to just about any body of water to be up and running.
I agree jtriplett38, people need to read more carefully.
The jetpack is indeed water powered, it has no motor attached at all. Granted that meens that all the work is being done by the compressor on the boat. I bet you could build one of these attached to the base of a water dam, no motor at all - it would be entirely "WATER-POWERED?!?!?!?", though it couldn't go very far.
PhilInYork is quite right about the water pressure. That's probably why they are so confident that the next prototype will be more powerfull.
Anyone who is worried about steam should read the article again. The water is cold.
Its use is limited, but it would be heaps of fun. I'd certainly pay to have a go, so would thousands of other people. So its use in tourist centres is guaranteed.
nobody reads anything.... the concern over steam was in a scenario of using the jet pack to fight fires over water... if you're hovering over a large ship fire (or the like) I would think there could be problems with steam (but more likely problems from direct heat)
nevertheless, this looks pretty cool and will definitely have a market
Big deal. Mario had one of these in 2002.
i think if it had higher pressure the possibility for injury in case of equipment failure would increase. as it is now it would "probobly" just hurt alot, and not shear off any body parts.
Sorry to burst your bubbles on smaller diameter hoses.
Although it is true that a smaller nozzle will create higher pressure, ask any firefighter or plumber whether a larger hose or smaller hose will cause more more friction in the water.
You will have more pressure and GPM loss in a smaller diameter hose.
Now for the physics.
The smaller hose has a higher ratio of water passing along the "stationary" hose wall versus water flowing through the center. The water passing along the hose wall will experience higher friction and will lose energy.
Now, the pump must overcome both friction in the hose as well as the weight of the water. This is why fire engines will be setup to daisy chain when pumping up hill.
Another reason to keep the hose large is to reduce the pressure and wear and tear on the fittings. Lower pressure, parts last longer and don't need to be as strong. Compare the hose fittings on an air conditioner to those on the coolant hoses in a car engine.
As for height, 30 feet sounds about right for a 4 inch hose. Any larger diameter and the pump size would have to be increased dramatically.
I don't have time for further analysis at this time, but I am very impressed with his engineering abilities. Looks like fun. It would also be useful for beach rescue.
You cannot evaluate this on practicality. That's not the point. It's about as practical as a jetski or wakeboarding. It's pure Fun!!! It's a great exercise in hobby engineering and he's gone the extra mile in "finishing" his design. He's going to sell a few of these for sure, but he's definitely having way more fun than most of us have had in a while, or will ever have for that matter. :-) Great Job!!!
What a superb piece of work! My impression is that this chap has spent years on this.
My friends and I built a proof of concept water propelled jetpack using the same principle in 1995 in West London (took out a British "provisional" patent (a quirk of British law) on the concept). I had sketches and a couple of photographs on an Earthlink home page for a few years until I dropped using that ISP. The intent (and we were cash-strapped ex-students) was to modify a jet ski with a centrifugal pump rather than an axial flow pump and use that as the power source. For our proto we simply used a couple of portable fire pumps.
To the comments above, I suspect the correct term for this would be a "water propelled jetpack/tethered flying machine" as it is technically powered by gasoline/petrol.
We used a 2" ID pipe for the early runs as we were limiting ourselves to 15 feet and were concerned about flexibility, if I recall, we could have achieved 30 feet, it was simply a question of horsepower and cash for the extra length of hose (seriously we did this on a budget, the parachute harness was 80 quid, and the firepumps were 60 quid each). The thing to bear in mind is that you need to weigh up the benefits/problems of the hydrodynamic drag of the smaller hose with the mass of the water you are having to lift in a larger diameter hose. 4" having 4 times the mass of water that a 2" one would have.
We built a quick and dirty proof of concept that lifted my skinny frame (I was about 140lbs at the time) 10-15 feet. Stability was known to be a problem and it is interesting to see how he has resolved those issues.
I think the key here is to recognise what this bloke has achieved. I'm sure there's a few people out there that have built something like this independently, but he has brought it to a point where it can (at least for low volume) be productionised. Very, very impressive. I'd love to meet this guy. The work that has gone into this is probably waaay more extensive than would be realised at first pass.
Instead of asking a fire fighter or plumber, ask a mechanical engineer (like me for example). To use a smaller hose, the pump would be a high pressure/low flow type with the same power input. The lower flow rate allows for a smaller, stronger hose. Mass velocity is what limits flow rates in piping, not pressure drop. The pressure drop would not necessary increase. However, you could run with a much higher loss as an added bonus, because with say 400 psi, a 20 psi loss is less important than it is when running 60 psi. Wear on fittings is irrelevant; they are standard fittings and nozzles. The nozzles would use the higher available pressure to accelerate the water more. Less water, moving faster creates the same force as more water, moving slower. F=ma.
The efficiency would definitely be lower, but who cares? Miles per gallon is not exactly the point. The pump would actually be smaller, not larger, because pump size is affected by flow rate, not pressure. It might a different type of pump, or multi stage, and perhaps more expensive.
For all we know, they have tried all of this and are already running at the optimum. Bottom line: “Nice Make, man. “
Perhaps it could be used by fire-rescuers to jetpack up several stories. They do have lots of water and big pumps. They could fly right from the top of a pumper, as hose is trailed out behind them.
I wonder if it would help lift the hose if they had a few rigid sections of pipe with downward-facing nozzles at the top of each section. The weight of the hose below each section would hold them vertical and point the nozzles down. This would make the hose self-supporting.
Also, altitude creates a static head. So a low pump pressure limits how high it can go.
Head (ft) = Pressure (PSI) X 2.31 Specific Gravity, so it looses 1 psi pressure for every 2.3 feet of altitude. That 60 psi drops to 47 psi at 30 feet altitude. Running a higher pressure would mean much less affect of altitude; 400 psi would become 387 psi.
The hose gets heavier as it goes higher. A 4 inch hose, 30 foot long would weigh 50 pounds of water if I calculated it right.
The heavy hose and the loss of pressure must meet at the 30 foot altitude limit.
The technology to do that has been around for 100 years; makes you knock yourself in the head and say “Why didn’t I think of that ?”
Now I know what I want for Christmas :)
Raymond Li Hats Off to you as you made impossible to possible.
www.hindlist.com Free Classifieds Website started to clinch for the superiority in its market of free classifieds. It has started very recently but yet has gained the immense responses from its users, mainly due to its user friendly attitude to po
It's good for recreation and or patrolling the sea, lakes or any body of water deep enough to allow the water pump and motor to trail along freely, to bad it can't leave the water!
Coming up with the idea to build it was hard to come bye, but the price is to expensive compared to the equipment needed to build it, hopefully the price will go down when they are mass produced.
Dr. Evil's henchmen could definitely use this to patrol the beaches around his evil lair. Equip a few of them with machine guns (along with laser-equipped sharks swimming below) and you'd have yourself a really nice killing machine.
I could see these showing up at theme parks, kind of like the giant swings you have to pay extra for. I don't see much of a market for individuals to purchase. It sseems it would get old after about 5 minutes.
super mario sunshine much?
Possable firehouse life saving qualities in this product. Hook-up to a firetruck and launch, could have multi uses. One life saved would be worth it. Cool YouTube. One of the best items I've seen in Popular Science that could save a life instead of taking one.