Sorry that’s all pretty much over my head. Lol. I didn’t need to shoot to 300’. I was aiming for accuracy over distance.If I recall its either orifice size rough equivalent or usually CFM at 100 psi or other specified pressure drop dry air.
One time I reviewed a phd thesis where the simple Gsuit and positive pressure breathing spring/ball valve was possibly to be replaced by a motorized ball valve or throttle-like valve, I can't remember, and what struck me was trying for a high flow spec with very low pressures and pressure drops. Point being ya gotta port and flow bench your engine, I mean apta valve for the most horsepower. But make it too big and you'll lose torque. Well, not really, but at a certain point you won't be gaining much more. I think I've encountered valve overlap, in a sense.
My rope launcher (pneumatic)
- Thread starter Whisper
- Start date
I just used my super light slingshot, short, heavy latex tubing. Kicks like a mule. Because my regular, heavy, long slingshot system tubing needs to be replaced. Two things: looking down a longer device helps eyeball aiming and there's less deviation from recoil motion with a heavier device. For recoil you can resort to tensing up your body for the shot. Recoil control is a big part of accuracy.
Don't worry, my last post was double entendre mixing up car engines flow stuff. Actual gist of it is that there's a limit to benefit of speeding up the pressure fill behind the weight because there's a speed or timing of the weight boogying down the barrel and the objective is to choose how much you want to keep up with the motion of the weight down the barrel. There's also probably choked flow for a good part of the firing that might explain some linearity you found. Choked flow means you push harder but the air doesn't go any faster through the orifice (valve) but with higher reservoir pressure you stay in that max flow regime longer, hence more air buildup behind the weight. With a big valve you just get massive transfer and maximum pressure rise. It can be debated whether that is indeed the best circumstance. Most likely yes if your goal is absolute max power. Which you said isn't your goal. Part of your keeping up with the timing is the milliseconds response time of the solenoid. Good choice in my view.
There's a guy who made a supersonic air cannon. More hp! Rrrrruh Rrrruh Rrruh - Tim the tool man Taylor
Don't worry, my last post was double entendre mixing up car engines flow stuff. Actual gist of it is that there's a limit to benefit of speeding up the pressure fill behind the weight because there's a speed or timing of the weight boogying down the barrel and the objective is to choose how much you want to keep up with the motion of the weight down the barrel. There's also probably choked flow for a good part of the firing that might explain some linearity you found. Choked flow means you push harder but the air doesn't go any faster through the orifice (valve) but with higher reservoir pressure you stay in that max flow regime longer, hence more air buildup behind the weight. With a big valve you just get massive transfer and maximum pressure rise. It can be debated whether that is indeed the best circumstance. Most likely yes if your goal is absolute max power. Which you said isn't your goal. Part of your keeping up with the timing is the milliseconds response time of the solenoid. Good choice in my view.
There's a guy who made a supersonic air cannon. More hp! Rrrrruh Rrrruh Rrruh - Tim the tool man Taylor
Thanks for the info. I’m Always looking to become better informed. The only problem with the hair trigger on the solenoid is the natural reaction to let go the trigger before the pressure chamber is completely evacuated. So then you need to burp the system afterward. I need to get it in my head to keep the trigger depressed to vent all the air.I just used my super light slingshot, short, heavy latex tubing. Kicks like a mule. Because my regular, heavy, long slingshot system tubing needs to be replaced. Two things: looking down a longer device helps eyeball aiming and there's less deviation from recoil motion with a heavier device. For recoil you can resort to tensing up your body for the shot. Recoil control is a big part of accuracy.
Don't worry, my last post was double entendre mixing up car engines flow stuff. Actual gist of it is that there's a limit to benefit of speeding up the pressure fill behind the weight because there's a speed or timing of the weight boogying down the barrel and the objective is to choose how much you want to keep up with the motion of the weight down the barrel. There's also probably choked flow for a good part of the firing that might explain some linearity you found. Choked flow means you push harder but the air doesn't go any faster through the orifice (valve) but with higher reservoir pressure you stay in that max flow regime longer, hence more air buildup behind the weight. With a big valve you just get massive transfer and maximum pressure rise. It can be debated whether that is indeed the best circumstance. Most likely yes if your goal is absolute max power. Which you said isn't your goal. Part of your keeping up with the timing is the milliseconds response time of the solenoid. Good choice in my view.
There's a guy who made a supersonic air cannon. More hp! Rrrrruh Rrrruh Rrruh - Tim the tool man Taylor
- Location
- Western PA
Wonder if there’s an easy way to rig a short delay circuit, where even if you let off the trigger it takes say, 3 seconds to time out and release the valve… I think there is but it’s been so long since I played with anything like that
Thanks. I appreciate your feedback!
If you ever want to build one yourself give me a shout. It was a fun project. It was no great savings in money especially with the solenoid and laser. But I don’t care about that as I’m a ‘builder’. I also make throw weights with my 3-D printer which is in another thread with pictures of my weights. Just do a search for 3-D printed throw weights.
3D printed throw weights
The needle shoots straight and true doesn’t seem to hang up or wrap around branches. The large weight is very heavy I don’t have a scale so I can’t be sure but it’s over 16 ounces. The big one landed hard on a rock and didn’t break or crack which surprised me I was expecting BBs everywhere...
www.treebuzz.com
- Location
- Western PA
Lol, it happens
For trigger hold can you change to a non-momentary switch? The kind that stays snapped into "on" until you pull it back to off.
For a circuit version try LM555 timer switch contact debounce and extend the pulse. But then you have to drive the solenoid with a transistor, have inductive snubbing etc. And then you're at the mercy of electronics in the field. You can socket the IC for quick switch out but other blown components mean soldering.
Was watching the supersonic air cannon guy Smarter Every Day and if you ever read the urban legend of a JATO assisted car splatting into a rock face cliff, this guy left the stitching pattern and logo of the baseball on a steel plate!!
For a circuit version try LM555 timer switch contact debounce and extend the pulse. But then you have to drive the solenoid with a transistor, have inductive snubbing etc. And then you're at the mercy of electronics in the field. You can socket the IC for quick switch out but other blown components mean soldering.
Was watching the supersonic air cannon guy Smarter Every Day and if you ever read the urban legend of a JATO assisted car splatting into a rock face cliff, this guy left the stitching pattern and logo of the baseball on a steel plate!!
I’ve been involved in robotics for years so I know my way around electronics. I even have my handle set up to embed electronics in there. Like you mentioned I prefer to keep the electronics out of the field. I didn’t however, know when I designed this beast, that I would retain residual air in the chamber which is why I used the momentary switch. I didn’t want to leave it on by mistake. Right now the simplest solution is just to burp the system after a shot.
Crazy about the hat design embedded in the steel. that’s just mind blowing.
My last robotics project was a 350lb lawn bot. It sports a with wheel barrow on top which empty’s with a 250lb linear actuator. 5mph top speed two 950nm wireless ir cameras and luminator. GPS waypoints. I was hoping to add LiDAR this year but blew my wad on climbing equipment. LolI’ve been involved in robotics for years so I know my way around electronics. I even have my handle set up to embed electronics in there. Like you mentioned I prefer to keep the electronics out of the field. I didn’t however, know when I designed this beast, that I would retain residual air in the chamber which is why I used the momentary switch. I didn’t want to leave it on by mistake. Right now the simplest solution is just to burp the system after a shot.
Crazy about the hat design embedded in the steel. that’s just mind blowing.
I got the impression you might encounter a partial fire from premature trigger lift/finger twitch.
Many years ago I retrofitted a gas mower with two rear drive units, a belt driven dc generator (pm motor) off the crank, castor front wheel and rc control with homemade pwm to the motors controlled by pots actuated by the rc servos, to isolate the two electrical systems for reliability. I give it low top speed so it couldn't get away and so you could run up and pop the onboard master disconnect should complete f-up occur. I used to have more Round Tuits.
Many years ago I retrofitted a gas mower with two rear drive units, a belt driven dc generator (pm motor) off the crank, castor front wheel and rc control with homemade pwm to the motors controlled by pots actuated by the rc servos, to isolate the two electrical systems for reliability. I give it low top speed so it couldn't get away and so you could run up and pop the onboard master disconnect should complete f-up occur. I used to have more Round Tuits.
- Location
- Western PA
I never have nearly enough Round Tuits. Oh the things I would build if I did…
I am presently trying to work things out to be able to cut my vehicle repair times in half or better which would free up a lot of time for more Round Tuits though…
I am presently trying to work things out to be able to cut my vehicle repair times in half or better which would free up a lot of time for more Round Tuits though…
That’s right you’re only going to do the job when you get a round tuit. And they’re hard to find. Lol
You used to be able to buy wooden discs that said “Tuit” on them.
Well…hummm.
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