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Posted: Sat Jul 30, 2011 10:33 am
by warhead052
Ah ok. So it pretty much has a check valve built in?
Posted: Sat Jul 30, 2011 10:36 am
by Gun Freak
Mine does, yes, but not the one in the video I posted.
Saefroch, I don't know if you saw my edit, but I plan to take the spring out of the schrader so it is easy to open.
Should I put a spring in front of the piston or will the crank shaft take care of that?
Posted: Sat Jul 30, 2011 1:06 pm
by jackssmirkingrevenge
Gun Freak wrote:Edit, I thought of a good idea!
I actually
made this 
[youtube]
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Farting machine in this case but if you hooked it up to a crankshaft...
Posted: Sat Jul 30, 2011 1:39 pm
by saefroch
Sorry, must have missed that edit, or just not read the post
. I've never taken the spring out of a schrader valve, so I don't know how difficult they are to compress without it.
Posted: Sat Jul 30, 2011 1:48 pm
by Gun Freak
Oh, jack...
Saefroch, I took out the spring and it's loose, there is no tension and even with pressure behind the stem it is very easy to push. I think it will work.
Posted: Sat Jul 30, 2011 3:35 pm
by saefroch
JSR, did you ever manage to measure how far that was oscillating?
Posted: Sat Jul 30, 2011 4:11 pm
by jackssmirkingrevenge
saefroch wrote:JSR, did you ever manage to measure how far that was oscillating?
As far as the outlet port wasn't blocked by the piston.
Gunfreak, unless you're using high pressure, I would suggest a much larger piston head.
A pressure relief valve could be used to drive the piston...
Posted: Sat Jul 30, 2011 4:20 pm
by Gun Freak
How would the air supply cut off on when the piston is on the upstroke?
Posted: Sat Jul 30, 2011 4:31 pm
by POLAND_SPUD
the piston exposes the vents -> pressure drops -> pop-off valve closes
I don't like that design - too many variables that have to be tweaked
Posted: Sat Jul 30, 2011 4:34 pm
by jrrdw
Fly wheel plays a big part in the design. Have you given any thought to that?
Posted: Sat Jul 30, 2011 4:40 pm
by Gun Freak
Yes jrrdw, I'm going to try to find a metal disk with a hole in the center, might even use a big washer or 2, but I need to find something pre made since I don't have the precision equipment to make one. What kind of flywheel are you thinking?
Poland, right, I wasn't thinking that that valve popped open. Sorry, I get it now.
Posted: Sat Jul 30, 2011 4:53 pm
by jrrdw
Gun Freak wrote:What kind of flywheel are you thinking?
That would depend on the over-all size of the motor. It would take some trail and error experimenting. To much weight will make it hard to start, not enough and it wont carry through a complete revolution. Washers are a good plan because you can add or take away as needed.
Posted: Sat Jul 30, 2011 5:04 pm
by Gun Freak
Good, because that way I can use a bolt or something for the crank shaft. The engine is going to be very small. Single cylinder only like 3/8 or 1/2" bore, a few inches long. Pressure as high as it will take. Hopefully about 50 psi. On a 1/2" bore that's 10 pounds. I don't know if it can handle that mch force but we will see! I'm anxious to get to ace and start this thing.
Posted: Sat Jul 30, 2011 5:07 pm
by jackssmirkingrevenge
POLAND_SPUD wrote:I don't like that design - too many variables that have to be tweaked
How about this, the pop-off piston is the actual piston. The piston is loose in the cylinder in order to stop it hanging.
Posted: Sat Jul 30, 2011 5:16 pm
by saefroch
Just a thought... would it be possible to do away entirely with a flywheel if you used a lot of pistons, with their stroke positions each seperated by just a little bit? For example, if you have 10 pistons, #2 would be 10% (by time) into its stroke when #1 is just beginning its respective stroke...