steam rocket

[Johansson]

That might be a reason, I don´t think I would have wanted more thrust anyway. It was a rather thrilling ride you see.

Where in Sweden do you live, Stoffe?

[racket]

Hi Anders

I've ordered Traux booklet , gotta know more about this subject , somethings not making sense to me :-((

Cheers
John

[stoffe64]

hi Anders!
i live in uppsala,working as a mechanic in the military forces

[Johansson]

Ok, a bit too far away from Östersund for me to do a day trip then.

[racket]

Hi Anders/ Stoffe

Got my Traux document today so have a bit better understanding of whats happening with steam rockets :-)

Anders , that drawing of yours looks exactly like the one in my document except for the sizes , they need revising to get the correct throat/exit ratio as the sizes are in diameters but the ratio is in areas .

Another document to put into my Files for later reference :-)

Cheers
John

[Johansson]

What I did was to calculate the throat and exit areas, scale them and calculate backwards to get the new diameters. The cone angles was kept the same.

[racket]

Hi Anders

Excellent news :-) ............................I've misunderstood your diagram in that case :-(

The Traux doc only gives an impulse of ~45 lbs -20 kgs thrust per pound of expelled "fluid" , your 90 kgs of thrust would have been consuming the water pretty quickly , .................how many litres did you fill the cylinder with ??

I hope I'm getting to understand this beast :-)

Cheers
John

[Johansson]

I filled the 20L bottle with 15L of water, any more and the pressure would start to increase at a frightening rate at a certain point.

The 90kg thrust was some sort of average value, we measured it with the kick standing on steel tubes and its rear was bouncing up and down from the thrust. The vapour pressure at that run was somewhere around 70 bar.

[racket]

Hi Anders

Thanks for the numbers ....................I'll see how Traux's data corresponds with "reality" .

Cheers
John

[Johansson]

Any progress on the project, Stoffe? We are waiting you know...

[racket]

Hi Anders

I've been running your "numbers" through Traux's data and I can't seem to reconcile your run time figures vs your pressure and water quantity ..........................was there a "restriction" upstream of the nozzle ??

From your video it appears as though there are a number of fittings between cylinder and nozzle , did any of those have a restricting effect on the flow ??

Was the fitting in the tank equipped with a bellmouthed inlet ??

Something isn't making sense here :-( .............................you were certainly getting the thrust but the other numbers are giving me grief ..................LOL, an you know how I like my numbers to make sense ;-)

Cheers
John

[Johansson]

Hi John,

There should be no restrictions upstream the nozzle, only a ball valve that has roughly twice the area of the nozzle throat.

I don´t think that we bellmouthed the tank fitting, it is still a fair bit larger than the throat to I guess that we figured that it wouldn´t matter.

I am fully aware of your need for logic in the numbers, so I hope you figure it out soon to avoid sleepless nights. =)

[mator]

Hi guys!
I made steam rocket engine from CO2 fire extinguisher bottle. It contain 2.9 liters of water. Its working pressure with CO2 60 bar.
For today I have already run it by 10 bar pressure. Here video:

Next I want to raise pressure to 40 bar by steps.

[turbochris]

I volunteer to strap that to my ass and give it a try. I need some good rollerblades and one of those areo bullet shaped helmets leave it to me.

[mator]

Mmmmmm.... Good idea!!!! I used to think about vehicle design.... But genius things are simple!!!!