It almost seems like a mistake. He might have meant to say, "precise to within 0.1 psi".

I'd ask.
No, the meter is accurate to 1 PSI. For digital displays "precision" simply describes the resolution of the display. +/- 0.2 or 0.1 PSI for this digital display.

There is no relationship between ...

It almost seems like a mistake. He might have meant to say, "precise to within 0.1 psi".

I'd ask.

No, it was because I had a calculus exam the next day and all I could think of was, practise practise practise.

What do I do with the spudbux? Can I order food? I'm not hungry now, but I will be later. I know this from previous experience.

I was reviewing for a calculus midterm that day.

As this has come up, I'd like to take the opportunity to reiterate my request - any takers? :D

I'll second that request.

I might just carry out that experiment using an HPA tank. Any suggestions on how to connect a steel pipe to the end caps. I think I would use steel pipe for the pressure hose ...

I played around with gasEQ. Does someone mind checking to see if the following would be reasonable for an insane 12X accident (maybe I should stay away from this stuff):


[Conditions] 3
Adiabatic T and composition at const V


[Reactants] ------------ No.moles ------------ Mole fraction
H2 ...

In my opinion the fatal blow to pvc hybrids came when noname's sch80 one exploded at 2x. There is no way I'd use pvc after such a low pressure failure, even if his pipe did have a defect.

Wow, I guess this is only useful data for normal combustion cannons and pneumatic cannons. I guess it's ...

Thanks guys,

Lentamentalisk , what kind of calculations can be used to find the spontaneous ignition point of hydrogen/oxygen?

Off to do some more reading on electrolysis (please don't think I just randomly throw out ideas I have not done any reading on)...

rp181 , does sodium hydroxide totally ...

Hello All,

This is a request for anyone to post their experiences with PVC at high pressures, whether it burst or not.

I am most interested in finding the limit of schedule 40, pressure rated PVC in sizes from 1" to 4". I believe this data will be helpful to anyone building a hybrid or high ...

Thanks, Ragnarok.

Would that 70-100PSI rule of thumb apply to oxygen/hydrogen mixes as well?

You will also get spontaneous detonations of your fuel canisters, because in order to fill your much larger chamber to 12x, you will need to have the fuel canister at 120x at the least.

Do not attempt this.

No no, I wouldn't do that. I want to use a 6-12X charge mix to fill a 1X (atmospheric ...

uhmmm yes you did....

1x mix is a 'proper' mix of air and propane at atmospheric pressure
2x mix is a mix of air&propane at 2atm and so on

Yes, that's why I called it a nominal 1X mix. It is 0.62 PSI above a true 1X mix, but it makes it easier to do the calculations. A my starting nominal 1X ...

What's wrong with any of the numerous methods that use electrical energy to ignite the mixture?

Nothing, I'm just having fun. We'll see if I ever get something like this off the ground.

DIY told me that a 2X propane/air mix will get me a maximum of 250 PSI for a short time and then the pressure ...

In my quest for an ever simpler means of construction, I thought it might be fun to try hydrogen/oxygen, created from the electrolysis of water.

I would be using this mix to fill my charges (same charge as seen here: http://www.spudfiles.com/forums/files/fueling_system_1_162.png except I would not ...

OK, I believe I have a recipe for filling a hybrid combustion tank in my head.

It is:

1. Decide on what --X (compression ratio) you want to end up with.
2. Assuming your chamber is filled with 14.7PSIa of air:
3. Raise the pressure of the chamber to 14.7 + 0.62 = 15.32 PSIa using propane. (I will ...