| Author |
Message
|
| starman |
 Posted: 05/19/2008 21:00 PM Post subject: |
 |
|
Big Daddio
Joined: 12 Dec 2007
Posts: 1370
2550.30 Spud Bux
|
I assume you've looked into these things....here http://en.wikipedia.org/wiki/Bell_Rocket_Belt#RB2000_Rocket_Belt
is probably the most successful interation....hydrogen peroxide based....none have used CO2 as far as I can tell.
As cool as this may sound, are you really sure this is something you want to pursue? On top of potentially dropping your butt out the sky at a little too high elevation, workable iterations of these things once built by corporations with endless budgets were able to come up with only modestly practical units.
Just sayin..... |
|
| Back to top |
|
 |
|
|
|
| brogdenlaxmiddie |
| Posted: 05/19/2008 21:06 PM Post subject: |
|
|
Lieutenant Colonel
Joined: 22 Jul 2007
Posts: 462
628.50 Spud Bux
|
| I must say, that the rocket idea for lowering you is not really feasable. Not many people want to have a GIANT ROCKET attached to their back. Your best idea is to have a parachute. |
|
| Back to top |
|
|
| BC Pneumatics |
| Posted: 05/19/2008 21:17 PM Post subject: |
|
|
Donating Moderator
Joined: 18 Jan 2005
Posts: 1155
2439.97 Spud Bux
|
I would first strap fins on a tank, and see how high it can launch as a rocket. Then compare it's weight to to yours. I think you will find you need a more sufficient boost.
Someone with more time than me can throw some general numbers in a thrust equation and see what comes out  |
|
| Back to top |
|
|
| mopherman |
| Posted: 05/19/2008 21:30 PM Post subject: |
|
|
Brigadier General
Joined: 03 Feb 2007
Posts: 796
847.70 Spud Bux
|
Just some thoughts here, may be dumb.
Stabilization- Tie a rope to your foot with sufficient resistance to keep you feet pointing down. Maybe a couple pulleys and a weighted....weight?
Safe Landing- Deploy a giant reinforced umbrella at the very top of your flight and drift down, Poppins style.  |
|
| Back to top |
|
|
| kablooie |
| Posted: 05/19/2008 21:39 PM Post subject: |
|
|
Master Sergeant
Joined: 18 Feb 2007
Posts: 159
279.50 Spud Bux
|
| What if you had the CO2 travel out across four longs arms that stretch horizontally out around you, that would give it some stability. Kind of like a big x with you in the middle. As for landing, you could attach you and the jetpack to a crane or something that would allow you to fly pretty high yet arrest your fall once you're done. As for one big solid rocket, I see you flipping in little circles heading towards the ground. |
|
| Back to top |
|
|
| FordGtMan |
| Posted: 05/19/2008 21:45 PM Post subject: |
|
|
1st Lieutenant
Joined: 25 Oct 2007
Posts: 251
188.37 Spud Bux
|
| I dont think a parachute would work because it takes hundreds of feet for it to actually catch the air, and it probably would be hard to let it flare out because of the lack of speed. |
|
| Back to top |
|
|
| prospudder |
| Posted: 05/19/2008 22:13 PM Post subject: |
|
|
Private
Joined: 19 May 2008
Posts: 9
21.43 Spud Bux
|
| you would need a hell of a lot of pressure to get you off the ground if you hope to sustain flight that long at least 2000 or 3000 psi and you would need to get something to change you direction possibly wings on your legs lol if your actually serious about this you better be ready to spend quite a bundle at least $15 per refill plus $400-$500 for all the parts large co2 tanks and regulators for pressures that high aren't cheap |
|
| Back to top |
|
|
| rp181 |
| Posted: 05/19/2008 22:32 PM Post subject: |
|
|
Major
Joined: 13 Dec 2007
Posts: 363
463.91 Spud Bux
|
X formation is good, that is if each bottle had exactly the same pressure and open at exactly the same time.
I just dont see this happaning, alot of people say there going to do things, but they dont (me included). |
|
| Back to top |
|
|
| kablooie |
| Posted: 05/19/2008 22:44 PM Post subject: |
|
|
Master Sergeant
Joined: 18 Feb 2007
Posts: 159
279.50 Spud Bux
|
| I'm with rp181, I don't see this happening. The weight of everything would require enormous power to be lifted, CO2 is not a very regular power source (temp. affects it), and I don't know how you would make it. I hate to be a downer, but other projects have the potential to be more successful and fun. |
|
| Back to top |
|
|
| psycix |
| Posted: 05/20/2008 10:48 AM Post subject: |
|
|
Major General
Joined: 25 Jun 2007
Posts: 1591
86.93 Spud Bux
|
I am afraid that CO2 doesnt have enough power to boost you into the air.
Rockets are one of the most inefficient things in life.
You will need ALOT of power to get a lil force.
I think BCarms's idea is quite good.
First construct a CO2 rocket without an human.
If it works:
I would recommend to do it in the middle of a lake, from a boat.
Make sure to check wind speed and direction. |
|
| Back to top |
|
|
| jimmy101 |
| Posted: 05/20/2008 12:11 PM Post subject: |
|
|
Major General
Joined: 28 Mar 2007
Posts: 1598
6774.04 Spud Bux
|
Like others have said, there isn't a chance in hell of this working.
1. If it was remotely possible there would be a web page out there somewhere describing it.
2. There isn't nearly enough energy in CO2. Doesn't matter what you pressurize the CO2 to, there isn't enough energy per pound. You really can't pressurize the CO2 beyond it's liquefaction pressure (well you can, but it won't actually give you much additional energy). So your total energy is very limited.
3. Rocket belts that actually work use fuel + oxidizer. Per pound, there is a heck of a lot more energy in fuel + oxidizer than there is in compressed gas or liquefied CO2.
4. You need to be ejecting massive amounts of CO2 to get the needed thrust. The CO2 tank's temperature will drop and that'll cause the pressure to drop. Net result, after a fairly short period of time there is little pressure in the tank even though the tank still has lots of CO2.
5. To get stable vertical flight you will need to do one of three things;
a. Use several nozzles out a fair distance from the center of mass. Now you have to get the thrusts from all the nozzles to be exactly the same or the thing will pinwheel and ram your head into the ground.
b. Move the nuzzle(s) well above the center of mass (some of the first rockets used this technique to get stability.) Not very practical because your head will be in the exhuast of the engine.
c. Gimbal the engines nozzle(s). Virtually all modern vertical lift rockets use gimbaled engine nozzles. The Apollo, Gemini, Shuttle, ICBMs etc. all use gimbaled engine nozzles. And, you need a way to control the gimbals. A human is probably much to slow to do it manually. You can't use fins for stability since you won't be moving anywhere near fast enough.
A fun idea but it won't work. |
|
| Back to top |
|
|
| Acdcmonkey1991 |
| Posted: 05/20/2008 12:20 PM Post subject: |
|
|
Donating Member
Joined: 30 Mar 2007
Posts: 389
393.93 Spud Bux
|
| Ok, so now that my idea has been shot down, I thought up a new one, what if I used high pressure helium to make a sort of water jet pack, like DYI car idea but, wiht out the steam part. It would be like high pressure water in a chamber and then release it with a valve. good? or no? |
|
| Back to top |
|
|
| rcman50166 |
| Posted: 05/20/2008 12:54 PM Post subject: |
|
|
Major
Joined: 19 Jan 2008
Posts: 381
1022.10 Spud Bux
|
sorry my caps isn't working. the reason why a water rocket works is because of rapid expansion. it stores water at high temperatures and pressure. when the pressure drops, so does the boiling temperature of water. so by releasing water you start a flash boil which is extremely energetic. so what i'm trying to say is that what you need is a liquid that you can rapidly change into a gas for this idea to possibly work. the real rocket belt uses h2o2 ejected by air tanks. it runs through a catalyst that changes the h2o2 into h2o steam. this transfer from liquid to gas is where the rocket belt gets enough thrust to lift someone and still be safe. even so the belt only runs for about 30 seconds.
another note, what is your budget like. the man i've read about sells his rocket belts for around 34,000 dollars. this is because he mass produces them too. that price doesn't cover the research and developing costs. this project of yours could very well reach a million dollars to fund. but there is information learned from the rocket belt's development that could save some money. first thing, use and aluminum or carbon fiber framework. use corrosive resistant carbon fiber tanks. also don't settle for any type of fuel that is less that 95 percent pure. and lastly always assume that pressure and temperature extremes are constant when experimenting, this will result in safe practices and less risk of injury. also, assuming you get this far, tether down the pack while protoype testing even if you man it. this is to prevent a stray rocket pack and to ensure a controlled crash if control is lost. also it serves to train the pilot. the rocket belt has been described to be just as hard to control as a small helicopter. a tether esures you get a lot of experience before you attempt to fly. |
|
| Back to top |
|
|
| MaxuS the 2nd |
| Posted: 05/20/2008 13:04 PM Post subject: |
|
|
Colonel
Joined: 19 Jan 2008
Posts: 617
779.45 Spud Bux
|
I don't know what it is with me lately, but I've been negative towards most new ideas.
Anyway..I don't think that this could work at all, Co2 powered Gokart - yes, Co2 powered snowcone - yes, Co2 powered Jetpack - unlikely.
There are so many things you would have to think about. Weight, stabilisation, landing and cost. I don't think that it's possible for you to balance all of those points well enough in order to create a jetpack. If you had said 'Rocket-Car', I would have been all for it, no doubt in my mind it wouldn't work. But a Co2 powered jetpack, I mean come on, be serious now.
I say it's impossible to build unless you have a massive budget, a machine shop, the know-how and a death-wish.
Good luck anyway.
I look forward to seeing it. |
|
| Back to top |
|
|
| jimmy101 |
| Posted: 05/20/2008 13:24 PM Post subject: |
|
|
Major General
Joined: 28 Mar 2007
Posts: 1598
6774.04 Spud Bux
|
| Acdcmonkey1991 wrote: | | Ok, so now that my idea has been shot down, I thought up a new one, what if I used high pressure helium to make a sort of water jet pack, like DYI car idea but, wiht out the steam part. It would be like high pressure water in a chamber and then release it with a valve. good? or no? |
Why use Helium?
The problem with a water rocket is that you can't actually store any energy in the water. All it is is "ejectable mass". The "ejectable mass" has to be lifted with the rest of the machine. So, lots of extra mass to lift but that mass doesn't actually contain any energy.
Heating the water lets you store energy in the water so at least your aren't lifting something heavy but void of any energy. |
|
| Back to top |
|
|
|
|
