A new investigative tool for striker. spring characterization has been presented

[Cal]

On another form,  a member has presented first data obtained by means of an inductive position sensor that plots the striker position as a function of time.

http://img.photobucket.com/albums/v398/pneuguy/HDDdata_zpsf7ca69a7.gif

I have tried to develop conversation there on how the method and data could be useful for advancing the developement of air gun systems,  but have met the stone wall.

Anyone here care to comment on the data plotted in the image attached?

cheers

Ca;

[Rdsail]

I'm interested but I not sure how much I can be of help. The best person here would be Bob (Rsterne) to shine in. I consider him the top guy here is research and development.

At least now I'm subscribed.

Best of luck
Daniel

[Cal]

Dan

No expert air gun designer exclusive ,  can you read graphs?

I have my interpretations,  but wait to hear others.

give it a go!

[HillGSA]

Isn't that the guy that copied the other guys patient?

http://www.network54.com/Forum/79537/thread/1283613640/The+subject+of+the+John+Bowkett+Hammer+Debounce+Device+came+up+on+the+Chinese+page---

No?

[Rdsail]

Well, you can see how it bounce. What would be interesting to see if there was way to measure the air waisted. What would be interesting to see is the different bounce at a set hammer force and different PSIs that way you could compare the air wasted.

My biggest issue with HDDs is that the reduce hammer energy. Due to friction. I think the only way to reduce hammer bounce all together is with a electronic hammer

[Cal]

without any consideration for any striker multi hit,

I see the total valve displacement and that the valve open time (duration) is plotted.

In this particular plot,  the valve opening event characteristics appear to be equal for both conditions.  At least the displacement plots over lay.

[Rdsail]

soft of...The HDD is a little lower so the valve is opening just a tad less. That little bit of difference can be a lot when you take  in to consideration that this is happening in milliseconds and a .01 to .02 of an inch means less air which translates to less power at the mussel. That tiny difference can add up to more. I can guess that the more the hammer energy the less the gap between the two is. I can also assume that most people that are looking at a HDD are looking at lower power out of the gun so that gap will increase.

Another thing, is how constant the hdd is on the hammer. If the pressure that the hhd applies to the hammer varies from shot to shot that would translate to larger SD on a string. When ever I mod my gun I always try to keep my variables to a minimum. This gives me constancy. A HDD ads another variable and the you add the ware and tare for the hdd and the area where the hdd engages the hammer. Which in the long run will happen.

[FuzzyGrub]

Approx 0.030" lift over 2.5 milliseconds.  Looks like the bounce didn't open the valve.

[Rdsail]

I did not noticed that but you are right. Once the PSI goes down then it will start opening.

[PakProtector]

I see no reason to believe the valve is opening on the bounce. I also believe this to be the best example he could generate in order to engage the, 'gracious! my hammer is bouncing paranoia'. There is no indication of valve stem motion, just the hammer bouncing. I found this to be able to open my valve when pressure was around 1k2 psi with a 30 gram heavier hammer. Like I have long gotten into trouble over there for saying, air wasting bounce is a tune-able qty with that rifle, and that is with the way heavy 79 gram hammer. Go lighter and quit worrying for one, careful tune will also do it.

Once again we have the worry quotient engaged, and still no guarantee that you'll get more shots...best to keep your money under those conditions.
cheers,
Douglas

[Cal]

May I suggest that we limit this thread discussion to every aspect of the graph data and tool prospects EXCEPT
anything that has to do with the need for  multi strike suppression?  Only to speak of the function in objective description of the observed motion data.

That topic seems to reduce everyone's objectivity, and I for one have no interest in the topic.

[Rdsail]

All the graph shows is that there is no air loose during the bounce and that there is a small loss of hammer travel with the HDD. That small loss can translate to a good amount of power a .01 or .03 in extra in area can be a significant amount of power.

I think that is all the chart shows.

[Ribbonstone]

Good data.  Of cource there is going to be argument about what the data actually means, but isn't that true of all data collection?

[Cal]

soft of...The HDD is a little lower so the valve is opening just a tad less. That little bit of difference can be a lot when you take  in to consideration that this is happening in milliseconds and a .01 to .02 of an inch means less air which translates to less power at the mussel. That tiny difference can add up to more. I can guess that the more the hammer energy the less the gap between the two is. I can also assume that most people that are looking at a HDD are looking at lower power out of the gun so that gap will increase.

good observation,  I had not noted the "slightly lower"  displacement of the striker with the device fitted.

So true that a little difference could be a lot of difference.

[Cal]

Good data.  Of cource there is going to be argument about what the data actually means, but isn't that true of all data collection?

Well,  It's hard to know if the data quality is "good",*  but if there is anything to it,  the inductive transducer will be a very useful tool!

I accept that each of us will see different meaning in the data.  My hope is that you will tell me something that you see, that I may have missed!

*( I am somewhat concerned about the motives of the poster, I trust that the data is not just "graphic art" but accept even that. ;-)

[Cal]

All the graph shows is that there is no air loose during the bounce and that there is a small loss of hammer travel with the HDD. That small loss can translate to a good amount of power a .01 or .03 in extra in area can be a significant amount of power.

I think that is all the chart shows.

Are not the time and displacement of the valve opening event of significance to you?  I recall that some work was done with o-rings on valve stems to determine the same thing.  and left the timing to complicated mathematics with several assumptions.

In these plots,  the valve opening is clearly all values above the .73 value of the closed valve as shown by the straight line to the right side of the graph for both conditions.

[Rdsail]

yes the displacement of the valve is important. But I think it is important across different pressures and not much on one pressure or at different hammer preloads.

Are you referring to the Bstanley mod? If you are this is very different. the oring are there to flatten the string as your go down in pressure in other words it is to remove peak of the bell curve. The oring might dampen any bounce but these are two very different things.

[Cal]

The graph also shows the time periods between the three impacts of the striker on the valve stem.

From the data,  the time period between the first and second strike is significantly greater than the time period between the second strike and the third.

[FuzzyGrub]

By itself, don't think this one graph can tell you much.  Need to send the measurement device to Bob, where he would use it for data collection as he runs it through a range of scenarios/tests.   

[PakProtector]

May I suggest that we limit this thread discussion to every aspect of the graph data and tool prospects EXCEPT
anything that has to do with the need for  multi strike suppression?  Only to speak of the function in objective description of the observed motion data.

That topic seems to reduce everyone's objectivity, and I for one have no interest in the topic.

considering the source of the data, that is not possible. the conditions under which he operates require consideration. he's in business to sell a device to stop air wasting bounce; that the hammer bounces is a given. That it can re-open the valve is the issue at hand. That data put up does nto show it opening, so why would you care if the hammer bounces? for his purposes, showing the air opening bounce would be useful, and yet the best data he has does NOT show it. Nor is there any guarantee of getting more shots with his device( since under most conditions, there is no air-wasting opening ). The Marauder could be tuned to benefit, but the overall peak in the performance would be higher with a tune that does not require such a device.

Really, recognize this for what it is, paranoia-inducing salesmanship. I have no intrest in it, save for pointing it out for what it is.
cheers,
Douglas