A New Method for Increasing the Efficiency of a PCP - the SSG
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A New Method for Increasing the Efficiency of a PCP - the SSG
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Topic: A New Method for Increasing the Efficiency of a PCP - the SSG (Read 322576 times))
K.O.
Eternally Tinkering
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Posts: 7111
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Real Name: Kirby
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #80 on:
January 03, 2016, 04:08:36 PM »
Stopped Spring Guide ,Slap Shot Goal/guide... hmmm looks like the Geat White North made it into the name..
Thanks Bob for sharing... much inspiration with built fact...that works and very well...
MotorHead well wow on being able to throw it together... inventive tinkering for sure... me I was just proud of my hardware store brass t_ports for my pumpers...
I wonder how many of the Big Builders are secretly monitoring the Gateway for the innovation shown by the folks here...
You guys are the Wildcatters of Air (well helium also)...
Is really is great being able to watch the work happening and hearing the discussion as it does...
«
Last Edit: January 03, 2016, 06:29:26 PM by K.O.
»
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Gerard
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Real Name: Gerard
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #81 on:
January 03, 2016, 05:18:59 PM »
All sorts of good thinking going on here, I feel lucky to be keen on tinkering with PCPs during a time of so much user-friendly innovation.
Bit puzzled by shorty's 'experiment' though... puzzled enough that I put a hammer spring in my Record bench vise and dropped a tiny hammer on it (the handle helping me to loosely retain control, maintaining the hammer on top of the spring). It bounced back up about 1/3 as far as I dropped it and kept on bouncing several times, lower each time. Then I took the spring out and closed the vise and dropped the hammer again. Clunk. About 1mm bounce at most, once only.
So my result is exactly the opposite of what he's claimed several posts back. Either he's 'misstating' his observations for some unknown reason, or my hammer and spring and vise are somehow magically doing the opposite of what they'd do for other folk. It'd be a bit of a head-scratcher if it weren't for rsterne's results being charted so very clearly, with efficiency going WAY UP when the SSG is used and tuned correctly. Results in actual airgun application seem to bear out what this simple experiment of shorty's demonstrates on my iron vise. Thanks for the reassurance Bob, unintentional though it may be. I'll be giving this thing a try sooner or later in one or more of my airguns.
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shorty
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Real Name: Tim
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #82 on:
January 03, 2016, 05:36:27 PM »
Gerard,
I had to go try it with a hammer after your post. Got the same results as you.
I then did it with the steel ball again and got the opposite results again.
What the heck ?
Truley, I am not trying to be misleading.
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rsterne
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Bob and Lloyd
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #83 on:
January 03, 2016, 06:04:01 PM »
I think that the O-ring at the back end of the (solid steel) spring guide provides a damping action on the collision of the hammer with the guide when launched back by the valve.... As Lloyd mentioned, when the hammer hits the guide, it transfers part of its momentum to the guide, which is actually then in a balanced state (both are preloaded) between the spring pushing it towards the valve and the O-ring pushing it the other way.... When the hammer strikes the guide, it likely moves a few thousandths of an inch, flexing the O-ring and dissipating energy.... To do that, however, as Lloyd mentions, it has to waste some energy moving the guide....
IMO, if a resilient (ie springy) cushion is used between the hammer and the front end of the guide, it can act like a spring (albeit a very stiff one).... Since during the hammer's round trip with the valve it is NOT compressed, it only takes a very small force to compress it, and it then stores energy (like a very stiff uncompressed spring), and can return it to the hammer again.... If we were seeing hammer bounce, then it might be necessary to go looking for a solution for that.... either in the form of a fluid damper, or a resilient cushion, inside the hammer.... but are we looking for a solution to a problem we just cured?....
bstaley, if I understand your idea correctly, the front of the guide hits the stem, it is sliding through a hole in the front of the hammer, with a stop on the guide on the front side of the hammer, and with the spring inside the hammer.... At rest there is a gap between the back end of the guide and the rear cap (or the front of the guide and the stem, take your pick).... The entire hammer, guide, and spring assembly is rattling around loose when uncocked, by the amount of the gap.... The hole in the hammer which the guide slides in, has to be long enough to keep the guide straight, relative to the hammer.... When you cock the gun, you slide the hammer back, which pushes on the spring, pushing the guide back to stop against the rear cap and the spring is then compressed until the hammer latches on the sear.... The guide is sticking a long ways out of the front of the hammer (whatever the hammer stroke is), and is just clear of the valve stem.... When you fire, the hammer slides along the guide, hits the front stop (integral with the gude), slows down because it has to now accelerate the mass of the guide (conservation of momentum), and the guide/hammer/spring assembly then strikes the valve stem.... with the front of the guide actually doing the striking.... The valve opens and closes, and on closing throws the entire guide/hammer/spring assembly back until the guide hits the rear cap.... It stops, and the preload on the spring arrests the hammer, just as in the SSG, and the assembly rattles around until it comes to rest (just like the hammer in the SSG)....
You state that there are no "ugly parts" sticking out the back of the gun (there doesn't have to be anyway, see my solution on the QB).... and indeed you should save some overall length.... Your gap between the back of the valve stem and the inside of the rear cap must be the length of the preloaded spring, plus the thickness of the hammer the guide passes through, plus the end stops on the guide, plus the gap.... On the SSG, the guide when uncocked is the length of the preloaded spring, plus the end stops, then add the thickness of the front of the hammer, plus the gap, but it moves back the distance of the hammer stroke when cocked.... The front of the hammer on the SSG, however, can be thinner because it just has to resist the load of the spring and valve stem strike.... It does not have to be long enough to keep the guide straight.... In the SSG, the guide is kept straight by passing through the gap adjusting bolt.... How much extra hammer length is required to keep the guide straight is the question.... If you had an adjuster for the gap (part of the tuning process), that length would have to be added to the rear cap.... I would guess that the net overall length of the two systems would not be much different....
Gerard, nice to see someone else thought the same thing about shorty's vice and spring experiment, it didn't make sense.... When I read what you wrote, I decided to check it myself.... I got the same results as you did, on the tail of the vice the steel hammer did not bounce very high, and rattled to a stop very quickly.... On the uncompressed spring, it rebounded about a third of the height, and made several bounces, decreasing in height each time, until it stopped.... I then took the spring, installed it on a bolt where I could preload it, and the more preload I added, the less the hammer bounced in distance, and the faster it came to a stop.... This makes perfect sense, as the time it takes for the hammer to bounce once (leaving the spring or vice until striking it again), is governed by the height of the bounce and gravity.... The less the rebound height, the quicker the return trip, and the fewer bounces before the hammer stops moving.... The stiffer the spring (and the steel vice is a VERY stiff spring), the less height, the shorter time for one return trip, and the shorter the total time before the hammer stops bouncing.... A preloaded spring lies in between a loose spring and the steel vice.... and the more preload, the less bounce.... It's a simple experiment that settles the argument completely, IMO.... The less the rebound height, the less energy in the hammer.... I didn't try it with a steel ball....
Bob
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
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Real Name: Tim
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #84 on:
January 03, 2016, 06:04:21 PM »
Just did the same "experiment" again. Same results.
I gotta hand it to Bob, his SSG system does seem to be better than a short stiff spring with negative preload.
on a side note,
The only reason why I was out at the work bench was because I was making a SSG on the lathe to test out on my marauder.
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rsterne
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #85 on:
January 03, 2016, 06:14:59 PM »
If you think about it, increasing the preload on any spring makes it progressively more and more like impacting a steel vice.... I think the AHA moment for me was the PERIOD OF VIBRATION of the hammer decreasing as you increased the preload.... Since the time of flight per bounce is strictly based on how high the hammer bounces (gravity being a constant), it becomes obvious once you try it....
I think you'll like the SSG once you give it a chance, shorty.... Think of it like a spring that takes 5 lbs. to compress the first few thou (as the O-ring relaxes) and then operates like a normal spring.... The more I think about it, the more I like the rear O-ring, even though I originally only put it I there to cushion the blow of the guide when it crashes to a halt.... I use a 90D, BTW, I don't want much give there.... Scott, you can try different ones and let us know what happens.... *grin*
Bob
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #86 on:
January 03, 2016, 06:25:36 PM »
Thanks Bob,
I am pretty sure it will out perform the short stiff spring and I will like it.
Just wish I could have completed the SSG without breaking it in half with a little to much turning. Time to start over.
not worthy when you rush something and 2hrs work turns into spaghetti. I started with 1/2 rod.
Sure looks a lot easier using a long bolt.
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Palm Coast, FL
rsterne
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #87 on:
January 03, 2016, 06:30:40 PM »
My spring guide is just a piece of the appropriate diameter drill rod to fit the inside of the spring (smooth, ground finish), and I thread both ends.... At the front I install the nut with green Loctite, tighten it up against the shoulder or the end of the threads, peen the end over with a hammer so it will NEVER come off, and then machine the nut and the end of the rod to the shape I want to fit inside the hammer.... You end up with something that looks like a long round head screw with threads only at the back end for your preload adjusting nuts....
Bob
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
shorty
Expert
Posts: 1936
yes
Real Name: Tim
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #88 on:
January 03, 2016, 06:54:10 PM »
My build was going on the lines of Llyods with a hollow spring guide. I was trying to still have control over the throw but the wall thickness was too thin.
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Palm Coast, FL
Gerard
Sharp Shooter
Posts: 702
Real Name: Gerard
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #89 on:
January 03, 2016, 06:59:56 PM »
Just for giggles (and because I LOVE my Sanyo Xacti HD, especially the 300 frames per second video mode!) I set up to try a steel bearing on my vise. Not using the tail section as I only have a 4" Record vise and that part's a bit small to make a good platform for bouncing such things. I made two video clips, one of the ball hitting the hardened jaws with the vise closed, the second with a spring such as I've used in my Brocock Atomic to drive the striker. In the first, I found that indeed a steel ball bearing 21mm in diameter and weighing 39grams (similar to the carved-down striker in my 2240 carbine, quite a bit heavier than the one I turned down in my Atomic) bounces a lot more than an 8oz hammer. Not too surprising considering that all the force of impact is focused in one tiny spot on the sphere, demonstrating maximum rebound potential for the material. A cylinder (similar to an airgun hammer) would be a more fair demonstration (as with the small square hammer I used earlier). Anyway, here's the bearing hitting the vise:
http://www.luthier.ca/other/forum/follow_the_bouncing_ball-vise.MP4
Plainly the bearing jumps up quite a bit, then comes down and bounces again, losing energy, then once more off-target and onto the floor. Now the spring:
http://www.luthier.ca/other/forum/follow_the_bouncing_ball-spring.MP4
The bearing landed almost perfectly squarely on the end of the spring, which was held firmly in the vise jaws. Not quite perfectly though, so it bounced off at an angle and managed to smack into one of the two LED lamps I had aimed at the experiment, knocking it off by about an inch. The lamp head was almost exactly 12" away from the spring, the same distance I dropped the ball bearing in each of the above tests.
Seems to me these demonstrations provide two useful pieces of information. 1), that hitting a spring (in this case just 27mm of which was able to move) with a steel weight results in that weight being bounced back with close to an order of magnitude greater force than when hitting solid steel, and 2), that spherical strikers are a bad idea.
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Motorhead
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #90 on:
January 03, 2016, 07:35:26 PM »
Understanding the physics behind the simple device "Newtons Cradle" .... you really need little else to catch a clue that disrupting the energy transfer between any contact breaks the cycle.
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lloyd-ss
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #91 on:
January 03, 2016, 09:16:24 PM »
Gerard,
Visual aids are always a help in understanding a concept. Thanks for taking the time to make and post those 2 videos. That rebound from the spring was pretty significant.
Springs, and things that behave like springs, can be helpful tools, or real annoyances. It is hard to make them behave exactly like you want, LOL.
Lloyd
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Central Virginia
An engineer by nature. The affliction is knowing that everything can be made better. It is easy to make one that works, but it is difficult to make on that works WELL.
My YouTube channel is Airgun Lab
rsterne
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #92 on:
January 04, 2016, 12:48:01 AM »
GREAT VIDEOS, GERARD.... MANY THANKS....
Today I installed an SSG in my 2260 reversed tank HPA.... It previously got 43 shots with JSB 18.1 gr., from 3000 psi down to 1400 averaging 958 fps (37 FPE).... It had a 1.75" x 0.040" wire hammer spring (14 lb/in) and took about 11 lbs. of effort to cock.... This is the gun I'm talking about....
I made a Stopped Spring Guide to carry a 2.00" long 0.040" wire spring (12 lb/in) with about 0.45" of preload (~ 5.5 lbs), and played around with the gap to get the same velocity I had previously.... The gap ended up about 0.040", and the cocking effort was about 12.5 lbs.... The ideal spring would have been slightly longer with a 10 lb/in. rate, but I didn't have one, and as it turned out it doesn't matter.... Even though the maximum cocking force is slightly greater, because it starts out at 5 lbs. instead of less than 2 lbs., it feels smoother and you don't have that sudden increase in force right at the end, that sometimes causes you to not quite cock the gun, which with the MRod magazine causes a double feed.... In all the shots fired during testing (over 200) I never had a mis-feed.... Here is what the old RVA and the new SSG look like....
The old RVA used a floating spring guide that was captive between the spring and the hammer and extended through the adjusting bolt as a cocking indicator.... The 10-32 nut on the back of the new SSG is against a shoulder on the 7/32" guide, so I didn't need a 2nd nut to lock it, I just snugged it up with Loctite.... so the total length when cocked is nearly the same.... During testing springs I noticed that the pressure guage wasn't dropping as fast as before, so I was pretty anxious to check the shot count and efficiency.... Using the same pressure range as before (3000 psi down to 1400) I got 60 shots (instead of 43) averaging 966 fps (8 fps faster) with an ES of 10 over the string (12 previously).... The shot count, and the efficiency, increased
40%
, to 1.49 FPE/CI (from 1.07).... I was absolutely SHOCKED and delighted by this result.... There is no question that the SSG can make a huge difference, particularly in a gun where you are pushing the power....
Bob
«
Last Edit: January 04, 2016, 01:26:50 AM by rsterne
»
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
K.O.
Eternally Tinkering
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Real Name: Kirby
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #93 on:
January 04, 2016, 01:08:54 AM »
A 1% es I do believe that helps those wanting tight 100 yard groups..
Was tight to begin with but every little bit matters I think...
«
Last Edit: January 04, 2016, 01:12:17 AM by K.O.
»
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rsterne
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Bob and Lloyd
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #94 on:
January 04, 2016, 01:24:46 AM »
With unsorted pellets, 1% is about as good as it gets over large numbers of shots.... Pellets typically vary in weight plus or minus 1% or even more, so that can account for the 1% ES right there, if the FPE is held constant.... No way I'm going to start weighing pellets, because if there is really a difference in velocity and trajectory, then you would have to resight the gun for each weighed batch.... unless you just throw out anything more than 0.1 gr from the average, or use them for testing.... I'm just not a good enough shot to notice a 1% ES, even off the bench at 100 yards....
Bob
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Motorhead
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #95 on:
January 04, 2016, 01:33:33 AM »
Bob,
being your rifles are OPEN un-muffled barreled .... what sound signature differences are you hearing ?
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Northern California ... Old Hangtown
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rsterne
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Bob and Lloyd
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #96 on:
January 04, 2016, 01:50:59 AM »
There was a small difference on the QB.... a much larger one on the first test gun and this 2260.... There is absolutely NO BUURRRPPPP that I can hear with the SSG installed wth a gap.... However, if you screw in the adjuster until you have any preload, instead of a gap, there is an instant doubling of the report.... I mean like LOUD !! ....
One thing I find extremely interesting.... Compared to the standard spring setup, when you are on the knee of the curve, approaching the plateau, the efficiency drops rather quickly, to the point going from, say, 950 fps to 980 fps might cost you double the air.... With the SSG, as long as you can maintain a gap, the efficiency doesn't drop as quickly.... It drops, yes, but not as fast as before.... Once you have preload on the SSG, however, the efficiency drops like a stone.... You can't mistake it when that happens, the report gets SO much louder.... It's almost like a switch, one more flat (1/6th turn) on the adjuster screw, you get another 20 fps but double the air used.... When there is a gap, it seems the velocity change is about 10 fps per flat (less with a fine thread)....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Motorhead
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #97 on:
January 04, 2016, 02:08:15 AM »
I had unscrewed the shroud listening and noted the SNAP indeed seems a tad crisper ... also making note when stop rod adjusted too close ( yet hammer wiggled ) when fired report was louder !
Came to conclusion the o-ring on end of stop rod was COMPRESSING equal to / greater than the gap setting. so for that millisecond valve is open & shut the stop rod appeared to NOT MOVE out of the way fast enough and poppet sent hammer into stop rod screwing with the dwell timing.
Tad more gap being greater than compression yield of o-ring and all seemed well enough.
*On a side note, the most recent spring hat with the o-ring on the end to act as a rebound buffer between hammer and stop rod was installed this afternoon. Appears to work no different, tho it may be
Got no sound or optics equipment to validate.
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rsterne
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Bob and Lloyd
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Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #98 on:
January 04, 2016, 02:22:58 AM »
You can definitely tell when you have a gap.... no question about that.... It doesn't seem critical how big the gap is, from what I can tell as long as it's there.... The amount of gap certainly affects the velocity, however, with the speed dropping in a fairly linear fashion as you increase the gap.... As you drop the velocity, you use progressively less air, and the efficiency increases as well.... so you can trade off power for shot count by changing the gap....
Bob
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Coalmont, BC, Canada
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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
rkr
GTA Senior Contributor
Posts: 4343
Re: A New Method for Increasing the Efficiency of a PCP - the SSG
«
Reply #99 on:
January 04, 2016, 07:28:49 AM »
It would be easier if we could make a folding rod that holds the spring in compression, like the shell in shock absorbers. No need to drill the back plug or anything, just slip a compressed spring package in place of the original spring. Alternatively it could be a two piece shell around the spring where one half goes inside the other. Just add some sort of length adjustment to the package. Original power adjusters could be employed as well.
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Finland
Huub Viking Mk2 .22 bullpup - grab'n go gun
BSA Scorpion SE .177 - 12 fpe UK model
BSA Scorpion .25 - 100M BR gun at 60 fpe
BSA Scorpion .172 - 100M BR gun/trainer at 60 fpe
Evanix Blizzard .257 - 160 fpe
Exanix Sniper X2 .45 - 270 fpe silhouette gun
Drozd Blackbird HPA - 1200 rpm full auto fun gun / meat grinder
Evanix AR6 carbine/pistol
+ a couple of springers
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A New Method for Increasing the Efficiency of a PCP - the SSG