Calculate Your FPS in Easy and Effective Way

[bennedose]

Sorry. Audacity sound finder was no good because the gap between the end of the gun firing sound and the sound of the target being hit is less than 0.1 second and sound finder does not allow any gap less than 0.1 seconds. This happens because of echoes in the area which extend the length of the gun firing and pellet striking sounds. The sound is not "bam+thunk". It is bammmthunnnk which sound finder thinks is one sound. So I have to do it manually.

But I found a funny anomaly today. Using the same SDB 50 air rifle at 16 meters (measured) I got a sound length of about 125 milliseconds over two consecutive shots That works out to 128 meters per sec or 426 fps over 16 meters which is faster than the 310 fps I got over 10 meters. Weird.

[joywarrior]

Audacity for my gun was set to find sound occurrence between two sounds with a gap of .05, I think .05 is less than .1 - So I don't know what version of audacity you are using but I loaded the pictures strictly for this purpose. To demonstrate that the settings can be reduced manually to .05 - I did 4 tests with four different kind of pellets using the option "Minimum duration between sounds " set to .05 and decibel set to 10, all other values made to be 0, and as far as I know the readings were constant. You can (and I have by the way) even set the sound finder for .025 which is still lesser than .1 and so on and so forth - But if you are comfortable with the manual method it would seem prudent to continue, as long as you are getting desired results. (but the manual method has a chance of high error rate because of human element).

As far as the strange difference between the two consecutive shots is concerned only two explanations come to mind...exceptionally light weight pellet - by fluke, in the lot, and the other I have mentioned already above, wrong identification of sound times T1 and T2.

Hope this helps
Regards
Joywarrior

[bennedose]

Yes I got sound finder to work by making minimum sound as 0.8 dB and min gap as 0.001 sec. Nice. But the velocity calculation changed (increased ) by about 5 mps/ 16 fps

[joywarrior]

Yes I got sound finder to work by making minimum sound as 0.8 dB and min gap as 0.001 sec. Nice. But the velocity calculation changed (increased ) by about 5 mps/ 16 fps

That much should be an acceptable error rate for me for me , unless you want accuracy to the hilt. In that case I suggest you should buy a chrono . Don't worry about it. The company declared fps of even the most expensive international guns vary on the test range and conditions by larger margins for various factors. This is a home made economical system of getting a rounded approximation. Few fps variance is acceptable . as long as it is consistent. Whatever settings you put in sound finder, adjust them till you get only two time zones and not more nor less. In fact I would rate the fps deducted this way to be more true because the human element of physically detecting precise sound occurrence and starting point of T1 and T2 is now removed .

Enjoy which ever way you feel comfortable and convenient.

Regards
joywarrior

[bennedose]

No I am off sound recording for a while now. Been there done that

Next i want to try a hack method of photographing a pellet out of a rifle without a high speed camera. I have tried and failed many times over the last 20 years. But I will keep trying.

[joywarrior]

No I am off sound recording for a while now. Been there done that

Next i want to try a hack method of photographing a pellet out of a rifle without a high speed camera. I have tried and failed many times over the last 20 years. But I will keep trying.

Cool ! Now there's something I'd like to learn a thing or two about . Without a high speed cam, fascinating idea. Does it have to do anything with a fast shutter mechanism (if I were to draw a parallel with still photography, I'd say somewhere in the 2000 shutter range). No idea however about video system works

Best of luck.
Regards
joywarrior

[bennedose]

LOL! Well everything I have tried so far has failed miserably so I keep trying to think of some way to hack it.

[joywarrior]

LOL! Well everything I have tried so far has failed miserably so I keep trying to think of some way to hack it.

Let's apply to the principle " If we fail in our attempts, we must try and try again". LOL Sir !

[harshvardhan]

Thanks every one for trying my funda...
i was trying to deliver something which will be affordable and reliable......
now try this..... check the you tube video uploaded by me.......it is easy and no manual labor and eliminate the .01 second error too..

http://www.youtube.com/watch?v=Ge0DPZOaM60

[joywarrior]

Thanks every one for trying my funda...
i was trying to deliver something which will be affordable and reliable......
now try this..... check the you tube video uploaded by me.......it is easy and no manual labor and eliminate the .01 second error too..

http://www.youtube.com/watch?v=Ge0DPZOaM60

Yes in fact I already have the link from our last forum updates on the topic , will be checking it out tomorrow....Everybody should check this app out its wonderful.

[harshvardhan]

Have you seen IHP delivering over 700 fps...
all hard work is done by me Under full support and guidance of MR Basu....
He is the man behind achieving this Result.....

You also tune your SDB..atleast it will deliver 500-550 FPs..I think.....

[joywarrior]

Have you seen IHP delivering over 700 fps...
all hard work is done by me Under full support and guidance of MR Basu....
He is the man behind achieving this Result.....

You also tune your SDB..atleast it will deliver 500-550 FPs..I think.....

Yes, he is kind of a genius when it comes to air guns. I am in constant conversation and contact with Basu Sir , He gives practical options which can work at my level (rookie), Briha sir identified my interest very early and guided me to Basu sir long back .....now I have him, you and briha sir as lead experts and mentors to guide me...what fun !

Note : According to Sir this gun would deliver 450 fps after trigger tuning which seems right given the fact that its in the range of 285- 385(verified with 10grain-17 grain pellet).

Thanks
joywarrior

[harshvardhan]

450 fps will be with the original sdb spring..Ask mr basu that you can use cherokke or not....

[joywarrior]

450 fps will be with the original sdb spring..Ask mr basu that you can use cherokke or not....

Will do Sir and get back. Thanks for the tip .

Wishes and Regards
Joywarrior.

[harshvardhan]

After Tuning my rifle under guidance of MR Basu..These are the results[AVG velocity]
Pellets used Mastershot flat heads,
Note:-Muzzle velocity will be Higher that avg....
04/08/2013 1:14:00 PM , 1 , 745.74246
04/08/2013 1:14:14 PM , 2 , 744.85228
04/08/2013 1:14:33 PM , 3 , 739.33649
04/08/2013 1:14:48 PM , 4 , 741.97384
04/08/2013 1:15:02 PM , 5 , 738.24312

with proper tuning Indian air rifles can do much better
at least better that factory setting...