Cool explanation of some basic engineering principles! Ages back I took this sorta maths and extended it with a basic Euler integration to try and solve for the dart velocity in order to calculate the optimal barrel length. Sadly I didn't have a good set of scales at the time so I got some weird results with my made up numbers (the plunger "bouncing backwards" on the "air spring") that I picked out of the air. At that point I got into flywheel blasters and kinda just forgot about it Maybe I should revisit that code, use some accurate scales to measure stuff and see what I get -R
The problem I'm having is overcoming friction with the plunger head. I've even tried using 3" of precompression and lubricants and it either slides freely and has no seal, or has a perfect seal but isn't allowed to slide. Can you do a troubleshooting video for plunger heads?
3 inches of precomp is overkill, i.e. it tells me that there is something wrong with your setup. What is the actual ID of the plunger head you are using? What springs are you using? Did you drill anti-vaccuum holes in the body tube behind the piston chamber? (seen around t=1:03 in video). Using lubrication, make sure you are running it really wet. coat the whole rubber until it's dripping with lube, run it a few more times in your piston to distribute the lube, then add more. Seriously, if there is extra lubricant it will work it's way out.
Aeromech the 3" was just a test. It's 1 1/4" sch40 PVC. I'm using the superlative plunger head, a full k26 1/4" off full compression and lowes extra thick 1 1/2" rubber washer and white lithium grease. There was only 3/4" of actual precompression when the spring was new. You can sort of see the blaster in the newest video on my channel. It's using an RSCB because it didn't have enough power to use a hoppers used one 1/2" vent hole base with a drill bit
Looking at your video it seems like its performing pretty well. If you still have problems with it, I'd say switch out the grease to silicone grease (found near plumbing section) and maybe try thinner rubber washers.
How about the weight of a plunger? It should be as light as possible right? Heard some ppl saying that a heavier plunger will help pushing out darts at the end of the spring travel, but don't think that's true. Want to know what's you guys opinion, thanks!
NERF870525 that's the general rule of thumb for the purposes of acceleration, recall newton's law F=ma, the force exerted by the spring doesn't change, so if you increase mass, your acceleration from that forced is reduced proportionally.
As a student heading towards the STEM field of study, absolutely loved this.
Cool explanation of some basic engineering principles! Ages back I took this sorta maths and extended it with a basic Euler integration to try and solve for the dart velocity in order to calculate the optimal barrel length. Sadly I didn't have a good set of scales at the time so I got some weird results with my made up numbers (the plunger "bouncing backwards" on the "air spring") that I picked out of the air. At that point I got into flywheel blasters and kinda just forgot about it
Maybe I should revisit that code, use some accurate scales to measure stuff and see what I get -R
I really enjoyed this, and I'd love to see more of this, especially in pneumatic systems.
The problem I'm having is overcoming friction with the plunger head. I've even tried using 3" of precompression and lubricants and it either slides freely and has no seal, or has a perfect seal but isn't allowed to slide. Can you do a troubleshooting video for plunger heads?
3 inches of precomp is overkill, i.e. it tells me that there is something wrong with your setup. What is the actual ID of the plunger head you are using? What springs are you using? Did you drill anti-vaccuum holes in the body tube behind the piston chamber? (seen around t=1:03 in video). Using lubrication, make sure you are running it really wet. coat the whole rubber until it's dripping with lube, run it a few more times in your piston to distribute the lube, then add more. Seriously, if there is extra lubricant it will work it's way out.
Aeromech the 3" was just a test. It's 1 1/4" sch40 PVC. I'm using the superlative plunger head, a full k26 1/4" off full compression and lowes extra thick 1 1/2" rubber washer and white lithium grease. There was only 3/4" of actual precompression when the spring was new. You can sort of see the blaster in the newest video on my channel. It's using an RSCB because it didn't have enough power to use a hoppers used one 1/2" vent hole base with a drill bit
Looking at your video it seems like its performing pretty well. If you still have problems with it, I'd say switch out the grease to silicone grease (found near plumbing section) and maybe try thinner rubber washers.
I thought that might be the problem. Where can I get thinner washers? Does Home Depot have any?
Joe miller I always go to ace hardware and ask for rubber fender washers
Great engineering video! Vetted and approved by a fellow engineer!
How about the weight of a plunger?
It should be as light as possible right?
Heard some ppl saying that a heavier plunger will help pushing out darts at the end of the spring travel, but don't think that's true.
Want to know what's you guys opinion, thanks!
NERF870525 that's the general rule of thumb for the purposes of acceleration, recall newton's law F=ma, the force exerted by the spring doesn't change, so if you increase mass, your acceleration from that forced is reduced proportionally.
Pissed in science?