First off I know this is pretty much ludicrous on all fronts. Crude design and operation of a flying thing powered by jet engines constructed on a limited budget with less-than-professional knowledge... bad idea, excessive risk of severe injury or death if a problem with the engines occurs, either by falling from mid-air, being burned, or quite possibly both at the same time . I was surfing the web earlier and started toying with the idea. I have no intent of actually trying this until I learn more about it, and determine whether or not its even in the realm of doable. I'm just curious right now and looking for input from ppl here who have worked with homemade jet engines themselves.

now that we have that outa the way, here's the general concept I have in mind...

http://tinyurl.com/5f2553

hopefully it gets most of the ideas across. The grey parts (dark grey for steel and light grey for aluminum/lighter guage steel) are the frame. The user would stand on the platform/pegs at the bottom and buckle up via a harness on the wider grey part between the engines (frontal view). Assuming I used pulse jet engines (or something similar in dimensions/shape), these would be mounted to long cross beams (frontal view) and each one would share a pivot at the frame with one of the pink levers (side view). The user would pull the levers toward themselves, tilting the engines backward, causing the craft to accelerate, and vice versa for stopping for moving in reverse.

An inaccurate part of the drawing that I just noticed is that the business ends of the engines would probably do better if they were in line with the user's body so the craft doesn't have a constant tendancy to go forward. I would also probably want the engines mounted higher, so when your in the air the thrust is more "suspending" the weight rather than lifting it from some lower point and creating a top-heavy situation.

The fuel supply tank would have heat shields and be mounted low and behind the "engine-user-engine" plane, again to help keep the center of gravity low and square with the engines. This would also give some capability to warm the fuel supply if needed (due to rapid evaporation). The engines would be far enough out on each side to eliminate the risk of warming the tank to a point of rupture and barbequeing me in mid-air, but close enough that small adjustments to the heat shields could be made if the current setup is running the tank too hot or too cold.

http://tinyurl.com/59j9yo

That's one of the sites that I've been reading on. The whole page is about the "lockwood" style pulse jet, and at the bottom he's got a super-sized version that he made with an 1100 CI combustion chamber, which he predicts could produce around 240 lbs of thrust. I'm about 150 lbs, and just for guesses lets say the frame of the craft will be 50-60 lbs, the fuel 25-35 lbs (includes the tank), and the 2 engines themselves 60 lbs... Maybe 300 pounds max which I think is decently conservative.

Originally I thought I'd have the best luck building 2 large engines producing around 200 lbs of thrust each, but what about 4 smaller ones producing 100 each? I'd imagine that 4 smaller ones would be safer than 2 large ones. which would be more fuel efficient? weight efficient?

IF I successfully construct these engines and have them reliably producing the net thrust that I need, is there any concrete scientific reason why I simply WON'T get the thing off the ground? I'd like to hear suggestions for alternate designs if you have em, especially if you've fiddled with DIY/pulse jet engines before. If you just wanna tell me 'you're outa your fucking mind have fun in the ICU burn center and/or jail' that's fine too because I'm already plenty aware of that, so if you would include some brainstorming with your flames that'd be cool.


cheers,
-Jon

edit:

a few things i forgot...

landing gear - probably some type of tripod or quadpod with some spring to it to allow it to gently touch down and take off. it'd also keep it upright while it was "parked"

fuel - the guy on that site used propane for the most part i beleive, but what about jet fuel? For a crudely built setup like this should I stick with the stuff that comes prepackaged under lots of pressure so i dont have to mess with developing it myself (as i would have to in jet fuel)? itd be nice to be able to use a liquid that could be refilled on sight instead of having to go swap LP cylinders, but if it would step up the difficulty of things a lot then I could live without

[for anyone who has seen this one] apparently mythbusters did an episode about whether you could actually build a jet pack using plans available online, and they busted it. I think this is bullshit, because all it means is the specific plans they used weren't ones that could work. yes its a difficult thing to try and create in your garage, but that doesn't mean its a myth that is BUSTEDD! or whatever that stupd line they always say is.

skilled engineer?

haha i'm workin on it. im a junior in the program right now, so i guess i'm atleast part-way to being qualified to try and pull of something like this.

spatula tzar i feel like i've seen posts from you before about pulse jet experiments. is this correct or am I thinking of someone else?

the main point I'd like input on is whether I could do it with jet fuel instead of propane. The guy on that site said he can run one of those 240 lb engines for a little over 4 minutes on a standard bbq grill propane tank, so if I was making 400 lbs of thrust here, I would get a maximum of about 2 minutes off one of those if I matched his efficiency, which is unlikely. If I could use a substitute that would allow me to reach 5 minutes of operation, that'd be fantastic. With jet fuel or any other liquid at STP, There would need to be some sort of pressure provided. any ideas for the best way to provide this without adding much weight? A manually operated pump could be used to used to get things going if I could use the radiant heat from the engines to generate the necessarey pressure to sustain combustion (like the kerosene generators on coleman white gas stoves)

Your aircraft will be unstable. The difference between a helicopter and your design is that a helicopter's lift is above the centre of gravity. In your aircraft it is below.

A human could not control it. You will need gyroscopes and computers.

that's why I said that the engines would be mounted much higher than the drawing portrays. so that the points where thrust is coming from are well above the center of gravity, giving it a sense of suspension, rather than lifting from below.

quoted:

An inaccurate part of the drawing that I just noticed is that the business ends of the engines would probably do better if they were in line with the user's body so the craft doesn't have a constant tendancy to go forward. I would also probably want the engines mounted higher, so when your in the air the thrust is more "suspending" the weight rather than lifting it from some lower point and creating a top-heavy situation.

Oxygen Bottle: $30
Duct tape: $5
Rock: $0

Oxygen Bottle: $30
Duct tape: $5
Rock: $Depends on street price

Jetpack imploding on launch: Priceless

You need a better drawing.....Maybe look at what the jet man did, and use model plane engines. Use aluminium for as much as you can, maybe steel bolts or something.

If you've done enough research you'll see that;

a. They produce a fuck ton of noise
b. They produce a fuck ton of heat
c. Nobody in the right mind will do this(maybe give them some rock?)

Expect to spend a fair bit of $$$ on this. Maybe get a hold of a tomahawk cruise missile engine and strap that to the back? They only have ~500 parts(compared to 60,000 in a normal jet engine.....i think thats what the doco said), so shouldnt cost too much.

If you do indeed still go through with these plans, you will need to insulate the motors, probably with 2-3inches of asbestos/modern equivalent. This add's weight. The fuel can would probably explode in the current position. You will need to make it higher. The tubes from the tank will have to be the steel flexible cables to deliver enough fuel. The guy on that site said his "drank" fuel at 7.5lb/minute(i think). With 2, a small 9kg bottle will last just over 1 minute. Making a backpack-helicopter might be a better idea. Pro's of making 1;

a. safer
b. longer range
c. hover ability
d. cool/relatively no noise

cons;

a. more expensive
b. probably illegal to fly

Hopefully you change your mind on the motor idea, it has many, many flaws(the motor design)

"the main point I'd like input on is whether I could do it with jet fuel instead of propane"

You should be able to figure that out using basic chem, thermo & fluid dynamics.

thrust = force (in 1 direction) = mass x acceleration (in that direction*)

So, figure out what mass of air you can burn per given mass of fuel.


*can you spot the serious flaw in your design with regard to that?;)

Thankyou very much wolfy_9005. That was the kind of response I was hoping to get... critical and thought out.

First off, yes that drawing is certainly next to useless for the purpose of actually attempting such a project. I drew it up in 10 minutes in MS paint. Its main purpose was to divert the reader away from the stereotypical "jet pack" mental image of a futuristic thing the size of a book bag that can whisk the wearer across the sky at a moments notice. I also wanted to show that the engines would be mounted to the sides of the user (not actually on his back), and give an idea of how they would pivot for lateral movement.

Before any construction/buying, I plan to produce a 3-D model in AutoCAD of the linear dimensions, desired material, and desired type of all parts and members.
Off the top of my head, I know I'll need:

*tubing (round and square)
*bar
*sheet
*and plate

There are several very good local metal suppliers and machine shops in the area that I think will have most of what I need in the material I need... primarily steel, SS, aluminum. I will need ~2 sq feet of sheet spring steel (may use titanium if I can find a reasonable deal), which I can order online if need be. As I find each thing on the parts list at the shops and/or online, I’ll touch up the AutoCAD model with the exact dimensions, which were previously left open for this purpose.

An MS Excel sheet will be updated side-by-side with the model, and will keep a running total on the weight and cost of each part, as well as the total weight and cost, so there’s no surprises in either category (like putting the thing together and realizing it outweighs the max available thrust before I even get on it.)
In short, I'll know how much it's going to cost me and how much its going to weigh before any building takes place.


I have read about Jet Man before, and it is something I would take into consideration if this proves too difficult/dangerous.

I know they produce a fuckton of noise and heat. the noise part I really don't care about (I know its one of those ya say that when its actually running in front of your house things). The heat part will be examined and dealt with after more detective work is done.



I have added a middle step in this operation. Over winter break (or over summer vacation if I dont have time) I'm going to try and build a basic experimental model to get my feet wet. I've been 10 feet from one of these running before (so I do know the heat and noise), but I havn't made one myself. If this trial goes well, I'll probably try and attach it to a kart or something similar, and I'll consider the main project still a possibility worth further planning. If its a bust, I'll probably say fuck it, atleast for now.


How much do you know about pulse jets? Can you tell me if this weird shape would work?

http://tinyurl.com/6dh9br

The exhaust pipe is typically straight, and having it be the right length is critical to the proper function of the engine. If the resistance of a 180 degree turn was taken into account and everything, would a configuration like this work? The picture is overly emphasizing the shortness of the exhaust end. With the current design in mind, I'm guessing having it about 1/3 as long as the side with the combustion chamber and intake would be the best bet for this "personal jet aircraft" (better term I guess) operation.


Sorry I'm kinda dropping off on this post. I gotta do hw (which is also why I didnt make a better drawing... to busy) but thanks again for the replies.

I think you should try something a little less ambitious than human flight for the first attempt man.

I am. somewhere in my previous reply I talked about building a smaller basic pulse jet not for human flight over this coming winter break to see how it goes. just by-the-book, straight design, easily servicable petal valve. if it works we'll attach it to a kart (or something fun in the snow if we get any this yr), and if it doesn't then i'll scrap the human flight idea (atleast for the near future) and if i return to it it'll be a considerably different plan all together.

12 people have walked on the moon. 12 people have flown an untethered jetpack (it's just a coincidence).

ya that is a pretty small number. however you might be off by a few... Jet Pack International
http://www.jetpackinternational.com/equip.html
has several models that are starting to reach a state of practical use. The one available to he public for 200 grand has a max flight time of 9 minutes, and while $200k is a lot of money, I'm pretty sure there are more than 12 people on earth who can afford it, and who would jump at the investment. Where did you get that number? That can't be right.

let me clarify that the title of this thread and my use of the term "jet pack" was misleading. The design portrayed in my sketch and explained in my post probably doesn't meet half the qualifications of a jet pack. It would be a personal jet aircraft, consisting of a metal frame which secures the user, the engines, fuel, and landing gear.

If you wanna contest different parts of the design or ask how something would work, I'm glad to read it. If you want to comment on the new lesser trial plan of building a basic engine and using it for something o the ground, glad to read it. But there's no value in the other stuff.

Of course this would be a dangerous thing to build, much less to be strapped to while it attempts to lift itself off the ground. I acknowledged this in the first paragraph of the opening post of this thread. bad idea, excessive risk of severe injury or death if a problem with the engines occurs, either by falling from mid-air, being burned, or quite possibly both at the same time.

If you know something about this stuff but you have a moral objection to helping me build something that will quite possibly kill me then just discuss the trial engine I want to build for something on the ground. valve design is especially what I want input on.

Those petal valves, if i read correctly on that guys site, are prone to breaking. The way he said it was "They can last from 2 seconds to 20 minutes", and they look like their a pain in the ass to make.

Try and make one of those valveless jet engines using a piece of 3-4cm steel, just to see if it works. I'd assume you only need to make the chamber out of steel to take the heat, then the rest of the motor(the exhaust/intake) will only need to be aluminium. One major thing you need to remember is that jet fuel wont burn "as is"(they tested it on mythbusters). You need alot more oxygen, like what is provided using a compressor-powered turbine. Look at the burning points of the different fuels to determine the correct material. Scale bench test's are a good way to test proof of concept for reasonable cost before going out and spending shitload of money on full-sized models which may not work.

For the motor, consider adding a butterfly valve to it, to restrict the air flow, and completely kill it if needed. Ideally the fuel will be injected into the chamber at medium-high pressure, and if you can have it be injected in more then 1 point(maybe 1 on each quarter, or 8-16 if you can, although the injection nozzles might be too thin and become blocked/melted.

To prevent yourself from becoming a fireball in the sky, add 1-2 "flame stoppers" between the chamber and the fuel source. Im guessing jetfuel might not be such a big problem(unless under pressure in the tank), but gas definately will be.

The motors can be mounted further out if needed, maybe 1 meter either side of the passenger to help provide enough stability. You can use "I" beam instead of tube to save space, although it is slightly weaker.

Basic list of things you need;

1. Ignition source(and a way to reignite the engines should they flame-out in flight)
2. Fuel source
3. Parachute(anything higher then 10m and you can kill yourself, so during testing anchor your craft to the ground using rope, preferably steel cable so it doesnt melt :))
4. Way to keep the passenger strapped in, and a fast way to get out if required.
5. Motors
6. Way to shut off motors if needed
7. Something to mount the stuff too
8. Helmet, VERY good ear muff(and maybe ear plugs aswell), flame resistant clothing

Email me at madmax_9005 at hotmail d0t c0m if you want to talk more/have more questions.

Possible Fuels.

http://en.wikipedia.org/wiki/Propane
http://en.wikipedia.org/wiki/Petrol (although very volatile)
http://en.wikipedia.org/wiki/Avgas
http://en.wikipedia.org/wiki/Jet_fuel (jet a-1 is what i was thinking for the stuff above)

Some of them will "auto-ignite"(ie. flashpoint, where the heat is sufficient enough to ignite it), so an ignition system might not be necessary after it has started.

http://en.wikipedia.org/wiki/Ethanol (just a thought...)
http://en.wikipedia.org/wiki/Alcohol_fuel (apparently more energy-dense then diesel, but with a higher octane rating)

hey wolfy I sent you an email.

I am starting to like the idea of a valveless engine more lately. For some reason I was against it at first, but you are right about the unreliability and hassle of those petal valves, and I wouldn't want to build 4 of the shutter grid setups (for God's sakes lol)

Over break I'll probably build a trial engine using whatever pipe and tubing that I can get ahold of for as close to free as possible. My uncle has oil wells on his farm land, and for some reason the oil companies come and pull all the pipe outa the ground and just leave it there after one quits pumping (seems like a lot of unneeded labor if they arent even going to keep/recycle the metal), so I'll root through some of that. If I can I'd like to build more than 1, using different designs to see what gives the best results.


I'm now thinking about changing the plan to something more like a glider... a rough, lower speed and lower altitude version of the Jetman project (http://tinyurl.com/5pgt5r). He rolls out of a plane at 8000 feet, deploys an 8 ft wingspan, fires up 4 digitally controlled turbojet engines, and accelerates to 100+ mph in a matter of seconds. I'm thinking more along the lines of 1 center-mounted engine on a large wingspan with simple controls to flex either side of the glider.

I don't know yet how everything would go together, but it'd probably be a better idea than the "jetpack" operation for a couple reasons.....
*I would only have to build and perfect [as much as possible] 1 engine instead of 2 or 4 as I would with the jetpack;
*I would make the wingspan large enough so if the engine cut out, I would be able to glide into a rough (but reasonable) landing, whereas an engine failure on the jetpack would probably cause some kind of helical spin and violent contact with the ground which would probably result in paralysis which would probably result in the end of bedroom social life and ya just bad.
*I wouldn't need to achieve nearly as much thrust as I would with the jetpack.

http://tinyurl.com/6qvdfg I've been browsing this guy's site for a while now, and the link is to a page where he describes one of his engines that puts out about 100 lbs of thrust, which he speculates could move a reasonably efficient microlight aircraft. I'm not a pro on this stuff, but that guy IS, so that's atleast some token of confidence that this could work.


Like I said I don't have much right now on actual design. Just tossin the new direction of the project out there.

cheers,
-Jon

A glider is much safer for someone who is only doing R&D.

Those oil pipes might be good. I think they dont get a choice but to remove them or get fined, etc. But the biggest problem i see is that their usually pretty thick, maybe 2-3cm.(~1 inch). Bending that sized material will be a bitch. You might have to cut it on an angle to get the curve then weld it all together, but that might have a hole where the gasses can escape. Good thing about it is theres no way it could develop as much thrust than is required to move it, so you just need to keep it upright and start it.

For the glidr i'd recommend "I" beams for the span of the craft. It helps keep the weight down. For the spacers, i'd use flat bar/plate welded to the "I" beam. I'll(try) and draw a picture in paint to show what i mean.

http://i35.tinypic.com/166vzc.jpg

Im sure it should make sense to you :)

You probably need 1 spacer every 20cm, but more where the motor/person is, maybe as close as 5cm. The gaps can be used for fuel, electronics, etc. Closer to the wings you can probably get away with 1 every 25-30cm, but it depends how long the wings are. You want them as rigid as possible whilst still being lightweight. Carbon Fibre would probably sound like a good idea, but it's pretty flammable, so maybe only use it for wingtips, etc. Definately use aluminium sheeting directly under the motor, unless you can get ahold of some nice jet turbines :).

Ya most of that tubing is pretty thick... more like 1/4", but point taken. I'll use them however I can and fabricate the rest. I know I won't get all the parts I need for free from salvage, but it'll help atleast a little. I'll get that stuff figured out much better when I'm home and can actually get my hands on stuff.

In your sketch of the I-beams and spacers, is that supposed to be a birds-eye view? like basically make the span from a flat grid and then wrap w/e skin around it? Or is that a side view? So I guess it doesn't make great sense to me. Could you explain it a bit more or post another sketch?

I figured I would do the span more or less like how
http://tinyurl.com/66uaqd
this^ is set up, with cables going from the outer portion of the wings to the sturdier center frame of the craft. This would allow quite a lot of weight to be saved on the wings and its got that nice sturdy triangle structure goin on. Now are those things that you can sort of see on the span in that photo the spacers and I-beams you were referring to? As for the flammability of carbon fiber or w/e I use, I'm working on what the best location and means of mounting the engine would be, both to minimize fire hazard and to maximize the efficiency of use of the thrust produced. Finding a way to mount it as far in the rear as possible, and as low (below the span) as possible and getting good control would probably be the best.

Good thing about it is theres no way it could develop as much thrust than is required to move it, so you just need to keep it upright and start it.
Didn't understand what you were going for here. what did you mean?


that's all for now
-Jon

In your sketch of the I-beams and spacers, is that supposed to be a birds-eye view? like basically make the span from a flat grid and then wrap w/e skin around it? Or is that a side view? So I guess it doesn't make great sense to me. Could you explain it a bit more or post another sketch?

Good thing about it is theres no way it could develop as much thrust than is required to move it, so you just need to keep it upright and start it.
Didn't understand what you were going for here. what did you mean?


Yeh it's birdseye view.

For the prototype. 1/4" sounds a bit thick, but i dunno, depends how well you make it :)

I'll draw another pic on how you could sit the engine.

http://i38.tinypic.com/168isrp.jpg

Not to scale of course :)

Basically you have the curve bit halfway through the wing, and have it so the wing passes through the gap between the 2 pipes(exhaust/intake), assuming your building a valveless engine for it of course. You'd use steel for this part, insulated pretty well as the heat might weaken it so you have a wing that is severely anhedral, instead of only slightly(slightly allows you to travel slower before it crashes and burns)

http://en.wikipedia.org/wiki/Dihedral
http://en.wikipedia.org/wiki/Aerodynamics
http://en.wikipedia.org/wiki/Valveless_pulse_jet
http://www.desktopaero.com/appliedaero/preface/welcome.html

Some bed-time reading if your serious about it :)

from wikipedia: Without the presence of a mechanical valve, the engines require practically no ongoing maintenance to remain operational. The only large con is the noise, which can reach above 140 decibels.

http://www.pulse-jets.com/ <---has schematics on some different pulsejets, etc
Click valveless to learn more about the valveless engines, maybe ask in the forums, whatever. Taught me a fair bit of what i know today.
http://www.blastwavejet.com/pulsejet.htm

Thrust augmentors are also a good idea to achieve more thrust(sais so on the pulse-jets.com site)

Finally, something to watch before i go to bed :)

http://de.youtube.com/watch?v=Qj1YJEi-R9c

ya its still pretty thick. i dunno how i'll work it out, but I'll find a way. I can't really do any planning on that right now because I'm at school with no tools and no materials, so I got nothin else to say about it for the time being. For the actual engine that'd go on the craft, I'll definately go as thin as is structurally sound, hopefully in stainless.

Are you joking about the mounting location of the engine? I know the part about crashing and burning stradegy was in jest, but would there actually be some benefit of the engine being higher up? Cause I can't think of any.

* It would be much easier to mount it securely down low than up by the wing.
* There's the heat/fire hazard you mentioned.
* I'd be forced to stick with fuels that are under pressure at room temperature, because the fuel would have to go under the engine so there'd be no way for gravity to assist.
* A big one... having the engine mounted lower would create a pivot effect for the craft. This thing is going to be kinda low on power, so it'd be good to have the thrust in a position that would give some leverage to lift the front end. if the engine were up high, it'd be pivoting the other direction, and essentially trying to drive it downward.


Having liquid fuel is also a big one for me. The system I kinda have in mind would go like this:

The engine would be mounted as low on the craft as is reasonable, and the fuel tank would be 1.5-2 feet above it. The fuel would come from the tank in pressure-rated hose, which would change to metal tubing before reaching the engine. The tubing would make contact with the engine at some point and in some way (coiled around it, just running next to it, etc) and then travel back away from the engine, where it would run through some kinda throttle valve, and then from there go into the actual combustion chamber.
Having the fuel tubing make contact the outside of the engine would transmit heat to the fuel in order to generate pressure. I don't know how much heat would be needed to generate the fuel pressure to run the engine optimally, but I think that this setup could satisfy almost any demand. If it only needed a little pressure the tubing would just run near a cooler part of the engine, or if it needed a lot you could coil it several times around the hottest part of the combustion chamber.
Running the tubing away from the engine for the throttle valve before going into the combustion chamber would let it cool a bit for safety, but the pressure would still be up. The only other place for it to vent to would be back into the fuel tank, and a sturdy one-way valve could prevent this from causing any havoc.

Anybody know how this would work? I know putting combustable fuel under pressure and heat probably has some risk of flash-back and blowing up the gas tank, but I think the check valve (maybe 2 of em in series) would keep this under control.

-Jon

You have to think about it's center of gravity. With a low mounted engine(ie. supported underneath), you'd find it almost impossible to turn(think of a pendulum). With it mounted high, it becomes top heavy. If it's mounted somewhere in between, then it should provide enough maneuverability for your intended use.

I drew a better picture, with vertical and horizontal stabilizers in place;

http://i37.tinypic.com/2q0slnc.jpg

These are basically where the elevator's and rudder goes in a normal plane, but you said you wanted to make something like jet man's flying wing, so i left it out. It also helps keep the cost down(no servo's/hydraulics, no batteries, etc. Also saves alot of weight). The horizontal stabilizer(big flat thing above the motor) should provide lift, to help keep the back end up to stop it falling backwards. The vertical stabilizers helps keep it from twisting(like a helicopter without a rear rotor) when it's moving(one wing will almost always have more drag then the other, and it may/may not cause it to spin).

When you get back from school, etc buy some balsa wood and some glue. Then make a model of your desired plan, and test how much load you can add to it before it just hits the ground. Experiment with the location of the weight(ie. engine) and the horizontal stabilizer.

I didn't feel like reading all your stuff so maybe you've mentioned this already, but in the last issue of popsci there was a dude who's been trying this since 1980 or something and he's got something going. Instead of jet engines he just has huge fans mounted high up, and they burn fuel a lot slower so the flight time is extended. I'll upload a pic if I find it, or you could muck around on their website and possibly dig it up. It was in the 100 best inventions of the year or something.

Also, as a proven option for independent human flight, look up powered para gliding. Parachute + backpack with a prop + running ~50 yards = takeoff.

http://www.paradrenalin.com/

Godamnit I want to fly.

those PPG stuff looks like itd be pretty fun, albeit looking pretty gay, and feeling pretty gay for spending ~5500-6000 bucks for something that can only go like 25 mph. depending how the trial pulse jet engine works out, I'd like to construct this thing for about 1000... i dont know how realistic that is, but I'll mess with my options during more serious planning to see how close I can get to it.

Wolfy I've been busy and havn't had time to give your last post a very good look, but it does clear some stuff up. The post before gave the impression that you wanted the engine WAY up at the top of the craft. In the middle is more reasonable. I see what you mean about manueverability suffering more by mounting the engine lower, so I suppose a sweet spot between straight line stability and quickness in turns will have to be found. I'm not looking to compete in the redbull air race, so I'll probably shy a little more toward straight line stability, but I gotta be able to change direction, so point taken as well.

more on that later... for now, sleep.

cheers
-Jon

those PPG stuff looks like itd be pretty fun, albeit looking pretty gay, and feeling pretty gay for spending ~5500-6000 bucks for something that can only go like 25 mph. depending how the trial pulse jet engine works out, I'd like to construct this thing for about 1000... i dont know how realistic that is, but I'll mess with my options during more serious planning to see how close I can get to it.


Why do you want to fly? So you can look super cool and fly around like james bond or superman? Or to get up in the sky and see the world from a different perspective, to be able to do things you've never done before like fly to a friends house?

If you chose the later motivation, looks shouldn't really matter. Not too mention if you're building a homemade jetpack, it will look pretty ridiculous.

Also, I posted that more to motivate you to find other ways to fly. Why would I spend $6K on that? It's cheaper than pretty much any other way of flying [though I don't know how much powered hang gliders/ultralights run], and its basically the only one that doesn't need a runway to take off. Just open area. And good luck topping 25 with a jetpack, it's not like a ghetto rigged pack will have to control to zoom around like Neo in the matrix.

Now consider this- Parachutes can be bought separately, and that backpack prop thing doesn't look too complicated. Making your own engine here is a lot more viable seeing as the tech is already there, and it's fairly simple to do. It is not simple at all to be able to make a viable jetpack. If it was, then why wouldn't people with multi million dollar budgets have one by now? Because the tech is a bit to advanced for us right now. Not saying it can't be done, but the facts that the few jetpacks around only run for 30 seconds and cost crazy amounts of money say something about it's viability.

If you make your goals a little more realistic, maybe you'll actually get to fly.

runaway stapler, you mentioned that you didn't read all the previous material in the thread, so I think you might be a few posts behind... I'm hardly still on the "jetpack" idea. We are toying with design ideas for an ultralight glider, which is not an uncommon and undoable project by any sight. They've been around for years in a variety of styles.

About the powered para-gliding thing, DIYing it I would consider... I don't know what about their setup makes it cost 6 grand, but there HAS to be a way to build one yourself (and do a damn good job) for fuckin half that or less. I would prefer more of a traditional glider "plane" type setup, but A combo of the 2 might be acceptable too.

No I don't intend to look super cool or make even the slightest resemblance to any movie actors. I intend to do my best to get off the ground and look like a fucking lunatic in the process, screaming (half joy half terror) at a volume that any near-enough citizine may or may not be able to hear over the offensively loud engine (that will be highly likely to get me some sort of domestic disturbance citation).

However, if I'm going to hobble across the sky on a homemade aircraft, I'd prefer to do it with something more on the ridiculous side than the gay side (those PPG things do look gay).

It's not terribly related to design ideas, but watch the youtube vid in the link below. It's hilarious lol

http://tinyurl.com/3hjede

You won't be able to do this...

You won't be able to do this...

ya its very likely that you're right. i don't know enough about any of this to say that i'd be successful in getting it to fly, or even getting a reasonable glider put together. that's why i post stuff here... a bunch of ppl who i don't know who have no problem being critical of an idea will be able to point out potential problems and obstacles that i'll run into with a project, or tell me if its just down right stupid, before i start pouring money into it and figure it out the hard way. if i was without a doubt able to do this, i woulda done it already and posted pictures and a video of the thing in action, not asking noobish questions.

since the "jetpack" element of the thing is basically gone now, i probably won't even do the trial pulsejet engine anymore, atleast for now and atleast for this. I would still like to have an ultralight glider. Buying a used one would probly be the cheapest, but I do want some involvement in its creation, so if I can find a really cheap one that's damaged and good for parts, that's a consideration. When I'll be able to fund this depends quite a bit on what I find for summer work.

If not this summer, maybe in a couple years. As I said at the beginning of the thread, this whole idea is absurd and I'm just humoring ideas and dreaming right now.

Thanks for the input, especially wolfy. For now though, the flying thing is on the back burner.

-Jono