My friend's hybrid plans

[elad311]

Today, I found out that my friend interest in spud guns, and he saw
me some hybrid plans he made, he wanted me to upload it to the site,
so you'll tell if it's good, if it is, me and him will build it!
here:

[jonnyboy]

If that second ball valve off the propane tank is to vent you might as well put a quick connect there for the air. While the schrader will work it just seems nicer to have a quick connect. The burst disk holder in the diagram is called a union. I would get a copper barrel just for safety in case you get an ammo jam.

[elad311]

Ok, we can get copper..
but, do you think it will work good?

[ramses]

that depends on a slew of things. check out HGDT and plug in your planned numbers.

[Ragnarok]

so you'll tell if it's good, if it is, me and him will build it!

Being completely and utterly honest, based on what I know of your spudgun knowledge, I would strongly dissuade you from building a hybrid at this stage.

Hybrids, although they can be entirely safe in the hands and construction of an experienced spudder, are not to be trifled with, especially when your knowledge of launching in general is limited.
You might get lucky and do it fine - but you are far more likely to make a mistake you don't even know could be dangerous and do yourself a major mischief.

Seriously, at least churn out a couple of basic cannons before you start dabbling in hybrids.

[elad311]

Being completely and utterly honest, based on what I know of your spudgun knowledge, I would strongly dissuade you from building a hybrid at this stage.

Hybrids, although they can be entirely safe in the hands and construction of an experienced spudder, are not to be trifled with, especially when your knowledge of launching in general is limited.
You might get lucky and do it fine - but you are far more likely to make a mistake you don't even know could be dangerous and do yourself a major mischief.

Seriously, at least churn out a couple of basic cannons before you start dabbling in hybrids.

Yea, but my friend know about spud guns, and i sure he'll fix my mistakes..

[Ragnarok]

Yea, but my friend know about spud guns

That may be a different matter, and I can see that design, apart from the suggested use of PVC is largely OK - But I have no proof about your friend's skill (even the design, which is largely identical to a basic design that's been around for a while), so I have to base my decision on what I know of you.

Under those circumstances, I wouldn't recommend it.

The other thing is if your friend has experience, it would be nice to see him on these forums. No offence of course, but usually when giving advice to a pair of people, it's usually best to give it to the more experienced one, to avoid playing Chinese whispers by giving it to the other.

and i sure he'll fix my mistakes..

Much better not to make them in the first place.

[jonnyboy]

As ramses said performance depends on a bunch of stuff. Look around here in the hybrid showcase.

I just noticed you don't have anything about ignition in the plans. A peizo won't cut it for a hybrid a stun gun circuit would be easy to get a hold of but there are alot of options.

[mark.f]

I strongly disagree. Every hybrid I've made has utilized either a piezoelectronic BBQ igniter or small element out of an aim n' flame igniter.

[jonnyboy]

It will work but with any decent mix you will need such a small gap it could take hours to get small enough.

[DYI]

It will work but with any decent mix you will need such a small gap it could take hours to get small enough.

Before my hybrids got up into the 250psi+ range, I routinely made gaps smaller than 0.5mm in a minute or less with heavy electrodes which I manipulated with pliers, and they worked quite consistently with a relatively low voltage power source, even with 50 yards of speaker wire between the current source and the gap.

If you're going to be close to it (close for me being less than 30 feet, which isn't a huge risk in the case of this design), a piezo should be perfectly fine. If you need anything more than a single, tiny spark to ignite the mix, then it isn't mixed properly.

[jonnyboy]

Huh I thought I saw somewhere on here someone said you couldn't use a peizo in a hybrid.

[TurboSuper]

Looks good to me, although controlling the amount of propane getting to the chamber may be an issue. I'd reccomend connecting a meter pipe in "series" between the tank and the chamber.

[elad311]

Is it good to move the schrader, so it'll be near the pressure gauge?