Cobra Striker

Moonbogg · Tue Sep 22, 2009 7:31 pm

Thats it, I am making a video showing a quick demo on how to polish aluminum without power tools.

Moonbogg · Fri Oct 02, 2009 7:32 pm

Poll added! DO your worst!

Ragnarok · Fri Oct 02, 2009 7:42 pm

I can only really put my vote in the first category. While I'm not in the habit of labelling something as "sick", I've not seen a better executed piston hybrid.

Sat Oct 03, 2009 6:41 am

Indeed.Those that voted it sucks clearly don't understand it does quite the opposite.

It blows...very hard..very fast

This has driven me to polish my repeater...

inonickname · Sat Oct 03, 2009 6:52 am

May I ask what's the point in the piston? Surely it restricts flow or makes turbulence and it's not holding back a pressurized mix.

Though it is very nice.

Moonbogg · Sat Oct 03, 2009 7:11 am

inonickname wrote:May I ask what's the point in the piston? Surely it restricts flow or makes turbulence and it's not holding back a pressurized mix.

Though it is very nice.

What are you talking about? The piston holds the mix in. It bursts open at about 40psi and then is closed with no effort.

Willdebeers · Sat Oct 03, 2009 7:17 am

Moonbogg wrote:
inonickname wrote:May I ask what's the point in the piston? Surely it restricts flow or makes turbulence and it's not holding back a pressurized mix.

Though it is very nice.
What are you talking about? The piston holds the mix in. It bursts open at about 40psi and then is closed with no effort.

How does it acheive this?

Moonbogg · Sat Oct 03, 2009 7:22 am

Willdebeers wrote:
Moonbogg wrote:
inonickname wrote:May I ask what's the point in the piston? Surely it restricts flow or makes turbulence and it's not holding back a pressurized mix.

Though it is very nice.
What are you talking about? The piston holds the mix in. It bursts open at about 40psi and then is closed with no effort.

How does it acheive this?

Spring plungers. Nylon ball spring plungers hold the piston back until it blows forward. The nylon balls are aligned between the ventillation holes so they don't try to open, and they glide smoothly along the aluminum piston making it effortless to push the piston back in.

Willdebeers · Sat Oct 03, 2009 7:24 am

Im still clueless. Can you use an infinate X mix in a piston hybrid?

Moonbogg · Sat Oct 03, 2009 7:36 am

Willdebeers wrote:Im still clueless. Can you use an infinate X mix in a piston hybrid?

No. This cannon will only allow so much pre ignition pressure, about 40psi. All cannons have their structural limits as well. If you add too much fuel, eventually you'll add enough to either bend the cannon out of shape or simply blow it up. You have to design for the ammount of X's you want to use.

inonickname · Sat Oct 03, 2009 8:09 am

Oxygen and propane wouldn't go anywhere in a hurry unless you began waving the gun around with the breech open.

Have you tried the piston for pressurized mixes rather than oxy-fuel? How does it perform in comparison?

Moonbogg · Sat Oct 03, 2009 9:26 pm

inonickname wrote:Oxygen and propane wouldn't go anywhere in a hurry unless you began waving the gun around with the breech open.

Have you tried the piston for pressurized mixes rather than oxy-fuel? How does it perform in comparison?

The mix is pressurized, always, even when using purging. The fueling is not a displasive method. I have taken shots with pressurized O2 and the results are a hell of a lot better. I think the chamber never gets truly purged cleanly. All it does is waste a ton of O2 while leaving exhaust in the chamber. So I will use pressurized fueling, as the design was originally intended for. I removed the O2 gage for the video and tried purging because I figured it would be a more simple way to fuel, but it ends up being all guesswork as to when the chamber is purged and its wasteful as O2 is sent right out of the chamber in the form of dollar signs.

inonickname · Sat Oct 03, 2009 9:58 pm

Fair enough- I assumed you were using an atmospheric mixture.

What measures did you take to ensure the valve would not impede flow much?

Moonbogg · Sat Oct 03, 2009 10:05 pm

inonickname wrote:Fair enough- I assumed you were using an atmospheric mixture.

What measures did you take to ensure the valve would not impede flow much?

Used HGDT for a 1" opening and then increased the cumulative surface area of the ventillation holes well beyond 1" to compensate for friction and other losses.

kjjohn · Thu Nov 19, 2009 8:27 pm

Sorry if this is considered kicking up an old topic, but I hae a question about this cannon. You said the MAPP has pushbutton injection. How does this work? A spool valve? And what meters the correct amount of oxygen into the chamber?

Cobra Striker

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