hydrogen rocket

Moderator: Mike Everman

Sicarius
Posts: 11
Joined: Sun Apr 15, 2007 9:49 pm
Antipspambot question: 0
Location: NEW ZEALAND

hydrogen rocket

Post by Sicarius » Wed Apr 18, 2007 7:14 pm

hey i am new here in the pulsejet busness and was wondering if you can run a pulsejet on hydrogen gas
NOTHING IS IMPOSSIBLE

(note the two meanings)

Jim Berquist
Posts: 1396
Joined: Thu Oct 06, 2005 1:34 am
Antipspambot question: 0
Location: DEMING NM 88030

Hydrogen fuel!

Post by Jim Berquist » Wed Apr 18, 2007 7:36 pm

Answer: Yes From what I have seen , the P.J. will happily consume just about any fuel once hot. Hydrogen should start from the cold state.

Exhaust would be drinkable!

Gas and liquid would be two differant animals? From what I know , and that's very little hydrogen gas is not so good on compression. Liquid is a bear to handle and a leak can get nasty on the skin not to mention turn into a rather large ball of hot flames .

I wonder how long say 5oz of liquid would sustain a flyable P.J.?

The water formed within the exhaust would add to the thrust!

I'm sure some out here has tried it before! Wait for more replies and a answer will come.

Jim
WHAT TO FRAP, IT WORKED![url=callto://james.a.berquist]Image[/url]

Dave_G
Posts: 128
Joined: Tue Jun 08, 2004 4:33 pm
Antipspambot question: 0
Location: USA

Re: Hydrogen fuel!

Post by Dave_G » Wed Apr 18, 2007 7:44 pm

berquistj@peoplepc.com wrote:The water formed within the exhaust would add to the thrust!
Unfortunately, it wouldn't.

The total mass flow is unchanged.
Last edited by Dave_G on Wed Apr 18, 2007 9:36 pm, edited 1 time in total.

Eric
Posts: 1859
Joined: Sat Oct 04, 2003 1:17 am
Antipspambot question: 0
Location: United States
Contact:

Post by Eric » Wed Apr 18, 2007 7:45 pm

Hydrogen is pretty scary stuff, you dont want to just play around with it especially if you are new to pulsejets and are trying to figure too many things out at once while experimenting.

Hydrogen would be best used on little engines, where the properties of hydrogen would help tiny little engines run.

Big engines, if they built up a large charge of fuel / air, that would probably have a very nasty outcome.

Eric
Image

Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Mike Everman
Posts: 4930
Joined: Fri Oct 31, 2003 7:25 am
Antipspambot question: 0
Location: santa barbara, CA
Contact:

Post by Mike Everman » Wed Apr 18, 2007 8:13 pm

Just like acetylene, it would be very bad ju-ju to put in a big motor. Detonations will likely occur, the catastrophic type!
Mike
__________________________
Follow my technical science blog at: http://mikeeverman.com/
Get alerts for the above on twitter at: http://twitter.com/mikeeverman

Sicarius
Posts: 11
Joined: Sun Apr 15, 2007 9:49 pm
Antipspambot question: 0
Location: NEW ZEALAND

Post by Sicarius » Wed Apr 18, 2007 8:35 pm

ok well what kind of small engine would you recomend for using hydrogen
NOTHING IS IMPOSSIBLE

(note the two meanings)

Mike Everman
Posts: 4930
Joined: Fri Oct 31, 2003 7:25 am
Antipspambot question: 0
Location: santa barbara, CA
Contact:

Post by Mike Everman » Wed Apr 18, 2007 8:43 pm

A mini thermojet would be good, 8-10" long.
Mike
__________________________
Follow my technical science blog at: http://mikeeverman.com/
Get alerts for the above on twitter at: http://twitter.com/mikeeverman

Eric
Posts: 1859
Joined: Sat Oct 04, 2003 1:17 am
Antipspambot question: 0
Location: United States
Contact:

Post by Eric » Wed Apr 18, 2007 8:44 pm

Something the size of my mini thermojet or smaller. Im sure something the size of Steve Wallingtons micro thermojet would absolutely love hydrogen.

Eric
Image

Talking like a pirate does not qualify as experience, this should be common sense, as pirates have little real life experience in anything other than smelling bad, and contracting venereal diseases

Jim Berquist
Posts: 1396
Joined: Thu Oct 06, 2005 1:34 am
Antipspambot question: 0
Location: DEMING NM 88030

Post by Jim Berquist » Wed Apr 18, 2007 11:39 pm

Go to Erics:Beck Technoligy as seen on his post..... Site and look for small thermojets: Here is one that Steve made! You can scale his plans down if you ask how!

I'm trying to send you a link to Steves photo but it's not working ...your going to have to work your way down the link provided. Page 2 or 3 I think. After he shows the engine run, look for a JPG photo. Gustiment looks like 6-9 inches long.


http://www.pulse-jets.com/phpbb2/viewto ... et&start=0


Jim
Last edited by Jim Berquist on Thu Apr 19, 2007 1:01 am, edited 2 times in total.
WHAT TO FRAP, IT WORKED![url=callto://james.a.berquist]Image[/url]

Jim Berquist
Posts: 1396
Joined: Thu Oct 06, 2005 1:34 am
Antipspambot question: 0
Location: DEMING NM 88030

plans

Post by Jim Berquist » Thu Apr 19, 2007 12:46 am

a. Look at the Sticky on top of this tread or forum!

b. Beck has free plans.

c. Others have free plans.

Jim
WHAT TO FRAP, IT WORKED![url=callto://james.a.berquist]Image[/url]

Sicarius
Posts: 11
Joined: Sun Apr 15, 2007 9:49 pm
Antipspambot question: 0
Location: NEW ZEALAND

Post by Sicarius » Thu Apr 19, 2007 6:18 am

ok i have found the thermojet plans and am going to try to recalculate the plans so i can run it on hydrogen (without it blowing up in my face again)


what diamiter should the combustion chamber be. so i can scale things down from the larger plans
NOTHING IS IMPOSSIBLE

(note the two meanings)

toakreon
Posts: 47
Joined: Mon Apr 09, 2007 4:31 pm
Antipspambot question: 0
Location: London, England

Post by toakreon » Thu Apr 19, 2007 8:28 am

I'm sure I saw a video somewhere about an attempt to produce a 2 inch long pulse-jet. The researchers started with a 15 incher, then "approximately halved" it to 8 inches (ran fine on hydrogen) the halved it again to a 4 inch (which also ran).

I don't think they'd achieved the goal of 2 inches, but were working towards it. If I recall the 4 inch one ran at some absurdly high frequency - 1500-2000Hz or some such.

John

metiz
Posts: 1523
Joined: Fri Apr 21, 2006 6:34 pm
Antipspambot question: 125
Location: Netherlands

Post by metiz » Thu Apr 19, 2007 9:29 am

running an engine on pure oxygen, would it be able to work in a vacuüm?
Quantify the world.

Mike Everman
Posts: 4930
Joined: Fri Oct 31, 2003 7:25 am
Antipspambot question: 0
Location: santa barbara, CA
Contact:

Post by Mike Everman » Thu Apr 19, 2007 1:47 pm

metiz wrote:running an engine on pure oxygen, would it be able to work in a vacuüm?
I was wondering that myself some time ago. You'd have to increase the confinement for one thing...
Mike
__________________________
Follow my technical science blog at: http://mikeeverman.com/
Get alerts for the above on twitter at: http://twitter.com/mikeeverman

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

Pulsejet In Vacuuo

Post by larry cottrill » Thu Apr 19, 2007 2:48 pm

This would theoretically work fine for the front end, if carefully worked out. I think you would have some kind of long diffuser to get from compressed gas input down to reasonable inlet speed. Your main problem would be that you don't have any outside air to pick up at the tail end, to form the "tail piston" mass.

You would need to design your engine not as a pulsejet per se, but as a kind of "wave engine", where the blast mass is all you have to work with in this case. This could be very compact and fast cycling, but would take a lot of careful design to get what you want. A continuous burn rocket engine would probably be a lot simpler to design. There certainly have been rocket "lab demonstrater" engines that used compressed oxygen (or maybe it was compressed air) as the oxidizer.

It's hard to imagine why pulsing operation would be helpful. The only reason for pulsing is that it creates the necessary pressure swings for aspiration, and if you're force-feeding oxidizer, why bother? On the other hand, an interesting pulsejet application could be where the engine operated in some "inert" atmosphere as a pump, only taking in oxygen at the front end but still using the surrounding gas to form the tail piston in each cycle. That would be almost conventional design, and would be a lot of fun to get working. Of course, even for this, a useful application eludes me at the moment. You would need some requirement to move a high volume of inert gas (or maybe, highly polluted atmosphere) at zero pressure for some reason.

I guess one thing I can think of would be to remove poisonous gas or smoke or some such from a tunnel or mine shaft or something. Of course, there would have to be fresh air getting in to gradually displace it, just as there would be if a fan were used.

L Cottrill

Post Reply