valve hybrid design

[iknowmy3tables]

I recently met a friend at school who builds spud guns he has an interesting idea for a non burst disk hybrid. It's quite simple a solenoid valve replaces the burst disk and the ignition is wired to go off simultaneously with the valve
I'm not sure about it cause I don't know if the valve will open fast enough to do any thing

[ALIHISGREAT]

burst discs are cheaper and have higher flow, also wouldn't the diaphgram get damaged?

[Novacastrian]

It could work with a large enough valve, however trying to time it right would be a b!tch. Also it would be very expensive, with no "real" gains.

[Fnord]

The diaphragm may wear out eventually. Even if his timing is off, the valve will open on it's own, so there's nothing to worry about there.

Basically it'll work, but a metal piston valve will last longer.

[MaxuS]

Indeed, if they didnt go off at the same time or even if they did, the pressure would completely destroy the sprinkler valve.

[Fnord]

I don't believe the valve would be destroyed one the first shot. The first hybrid (Made by DR) used a sprinkler valve which never failed, though it was a pneumatically modded one. I don't think using an unmodded one would work the same.

[SpudUke5]

So does the same apply to the metal piston valve, meaning that if when you ignite the mixture, the piston valve will open by itself.

[Fnord]

^Yes, and it's been proven.
That's how my hybrid works.

[SpudUke5]

Ahh that clears up my head now. I wasnt sure how it would actuate because it didnt know what force would be pushing the piston back. Also do you pressurize the chamber first so that it seals, then release the mixture? Now that i come to realize some of it, if you can make a advanced combustion and a pneumatic piston cannon, then its pretty simple to make a hybrid; you just gotta know the difference in fuel injection. Thx

[iknowmy3tables]

I now that the valve will open on its own with the surge of pressure even if its late.
which is likely to happen first if a parallel switch set the igniter and the valve off at the same time; the combustion or the valve opening?

if the valve is the slower one then I could put a switch on part of the solenoid so the ignition goes off when the solenoid is half way up

[spanerman]

why not put a 200psi pop off valve as the ''pilot'' valve on the sprinkler?

[iknowmy3tables]

its been discussed it might not really do anything but a valve opening at the same time would not have to go off only at a certain pressure change

[spanerman]

if i can find a suitable pop off i will be testing that with a QEV....

[iknowmy3tables]

so can I varying pop off valve can be found at mcmaster
but the fact that it has to obtain a certain pressure before the valve stops restricting the flow is makes it slower

[spanerman]

is it signifigant though? i cant order from mcmaster...im in the UK