SpudFiles

come on guys this is galvanized steel pipe...when hitting it with a hammer, you hurt your hammer, not the pipe.
This is so freakin' amazing. That beats the crap out of my a$$...
i've done one mini hybrid, and curently optimising it, but this is....i mean, come on, this thing , this beast is impressive.
Mach 1 with a 5 gram marble....more energy than a .38 special bullet.

Terrific.

The reasoning behind not taking a handheld hybrid beyond 4x is that detonation could occur, which would almost surely destroy a galvanised steel launcher, due to the rapid pressure spike. While the material can likely survive the pressure created, it probably wouldn't be able to absorb the sudden impact, and could shatter, which would be very unpleasant (to say the least) for the person holding it.

I know about the DDT, it occurs with propane at 8x mixes....

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a DDT frequently occurs in an air rifle that combusts...
I've seen people take a hybrid over 5x, and have no probs. As you say, it is "accepted" that DDT can occur over 4x, facts tell that a DDT at 5x, or even 6x, is unlikely to happen in normal atmospheric conditions

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I didn't know that, my bad...But i run my mini hybrid at 6x mixes, and have had no problems at all, pressure peak at 350 psi.

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lol, i'm at 2 meters from my 1/2" chamber mini lol!! and i feel uncomfortable when firing it!! but i think it would handle 7x mixes if there wasn't any DDT.

Does anyone actually know the maximum pressure generated in a detonation? It might be enough to break some weak iron pipes, but if you buy high pressure (3000+ PSI working pressure) forged steel pipe and fittings... do you still think that DDT could destroy the pipe?

What exactly is DDT? I know it something like Deflagration to Detonation Transition... but wha exactly is it?

I'm sorry, I don't have time to answer all these questions today(I'm leaving in 20mins)
Maybe you guys can compile them all into a big list or something or send someone up to do an interview lol

Also, does anyone know if galfisk is still around? I haven't seen him on spudfiles, but I think he might like to know of the exsistance of another piston-valved hybrid.

To answer at least 1 question, I don't plan on taking it past 4x, mainly because my chamber has obstructions in it due to the spark gap design, which will help ddt kick in. And I don't plan on taunting the ddt gods:)

PVC Arsenal 17 wrote:What exactly is DDT? I know it something like Deflagration to Detonation Transition... but wha exactly is it?

it is when things transform from a high powered fizzle to a much more powerfull blast. It generates more pressure and destroys week pipe.
feel free to correct me if im wrong

It doesn't necessarily generate a whole lot more pressure (I heard a 50 bar estimate somewhere), it is the rapid spike which causes the real destruction, as most materials don't have the impact strength to survive it. DDT is when the flamefront excedes the speed of sound in whatever medium it is in. The rapid expansion compresses and autoignites the gases in front of it, causing the flamefront to propagate much more rapidly. OR, at least thats how I understand it. Depending on the material, it is also capable of destroying not-so-weak pipe (look at noname's test on 1/2" Sch 80 steel).

DYI: the valve is the same as any other piston valve, only steel. The interior of the barrel is rough, but I don't think the friction is enough to be noticeable.
DDT was found to generate 50 bar under normal atmospheric pressure. I'm not sure what ddt will do in a compressed gas enviroment. Right now I'm probably working with pressures of about 30 bar.

Jon89: since you probably didn't read it all, I said the total cost was about $40.

PVC arsenal: The pop-off opens, but I haven't been able to measure the peformance increase it gives. It probably does help a little, but nothing drastic.

Morpherman: read above^

Lukemc: The mauler was more powerful for a number of reasons; such as, it used a burst disk, there was no flow restriction between the chamber and barrel, and the barrel diameter allowed more energy to be exerted on the projectile.
However, I can put mixes in this gun that would probably destroy the mauler, so in the end I guess mine has the most potential power of the two.
Oh, and the mauler doesnt exsist anymore, so I win

Felex: I can use a bicycle pump on it, but at home I use my compressor for the convenience of it.

SB15:
1. I may be able to clean the wiring up a bit, but most of my friends think it looks cooler because it's so crappy. It wasn't really meant to have asthetic appeal, it was just meant to have the most power in the smallest space possible.
2. Actually, it's not epoxy, it's soldered (very badly). I didn't want to use a tee because the pipe nipple had the perfect volume already(it was 4.2 percent of the chamber volume)
3. If I take the hose off quickly, it doesn't really effect anything. I usually bleed out the pressure from the schrader behind the piston so no gas is lost.

Thanks for the comments everyone.