simpChrony-a Handy Ballistic Chronograph

[harshvardhan]

Added in 1 hour 8 minutes 31 seconds:
I will try to explain why pipe chrony is more accurate then Chronographs with larger area of detecting pellet


I will try to explain it by illustrating the above situation
Please refer to the Attached Image
In this picture you can notice the two points of pellet detection A & B,
The Green line Denotes the actual perpendicular distance between the two points
Red Line Denotes the actual line of fire.
Say the angle between this two is: XYZ ,
Now we will think it practically
Say ,
The distance AB is 1 foot,
We have used pellet rifle of velocity 800 fps;
So the time taken in Millisecond to travel A to B=1*1000000/800= 1250 Milliseconds,

Now think the angle is 0.01 degree,
Red Line=R
Green Line=G=1 Foot
Applying trigonometry G/R=Cos XYZ,
R=G/Cos XYZ,
Cos 0.01=0.995004
R=1/0.995004=1.005021085
Time taken to travel this will be =1.005021085*1000000/800=1256.27[Calculated in Chrony]
As Chronys will Calculate in Fraction of 4 it will be 1260;
So Chrony will display velocity 1/1260=793.36 instead of showing 800 Fps
So The error is of 7 Fps For 0.01 Degree only
Fore more angle error will be more….
So the larger detection area will allways show less velocity may be 20-30 FPS...where as these
problems does not impact pipe chrony.Hence Pipe chrony is the Most accurate one
And it is practically impossible to shoot with zero degree variation

[ganeshn]

Added in 1 hour 8 minutes 31 seconds:
I will try to explain why pipe chrony is more accurate then Chronographs with larger area of detecting pellet


I will try to explain it by illustrating the above situation
Please refer to the Attached Image
In this picture you can notice the two points of pellet detection A & B,
The Green line Denotes the actual perpendicular distance between the two points
Red Line Denotes the actual line of fire.
Say the angle between this two is: XYZ ,
Now we will think it practically
Say ,
The distance AB is 1 foot,
We have used pellet rifle of velocity 800 fps;
So the time taken in Millisecond to travel A to B=1*1000000/800= 1250 Milliseconds,

Now think the angle is 0.01 degree,
Red Line=R
Green Line=G=1 Foot
Applying trigonometry G/R=Cos XYZ,
R=G/Cos XYZ,
Cos 0.01=0.995004
R=1/0.995004=1.005021085
Time taken to travel this will be =1.005021085*1000000/800=1256.27[Calculated in Chrony]
As Chronys will Calculate in Fraction of 4 it will be 1260;
So Chrony will display velocity 1/1260=793.36 instead of showing 800 Fps
So The error is of 7 Fps For 0.01 Degree only
Fore more angle error will be more….
So the larger detection area will allways show less velocity may be 20-30 FPS...where as these
problems does not impact pipe chrony.Hence Pipe chrony is the Most accurate one
And it is practically impossible to shoot with zero degree variation

i guess in your calculation you meant the time taken to travel from A to B is 1.250 milliseconds.
if R=0.995004 and G=1.000000 then the corresponding velocity error is about 0.49% without getting the chrony in picture,which looks good. or if i consider your experimental 7fps low over the expected 800fps, then it translates to error of 0.875% low reading which is not too bad, where the chrony is contributing about than 1/3 of the error.
aligning the muzzle and the pipe chrony is equally tricky, on its own pipe chrony does not automatically guarantee to be perfectly aligned.


PS:this is not meant to downplay your efforts over the month in any way, rather something which sets me thinking loud.[/quote][/quote]

[harshvardhan]

Added in 1 hour 8 minutes 31 seconds:
I will try to explain why pipe chrony is more accurate then Chronographs with larger area of detecting pellet


I will try to explain it by illustrating the above situation
Please refer to the Attached Image
In this picture you can notice the two points of pellet detection A & B,
The Green line Denotes the actual perpendicular distance between the two points
Red Line Denotes the actual line of fire.
Say the angle between this two is: XYZ ,
Now we will think it practically
Say ,
The distance AB is 1 foot,
We have used pellet rifle of velocity 800 fps;
So the time taken in Millisecond to travel A to B=1*1000000/800= 1250 Milliseconds,

Now think the angle is 0.01 degree,
Red Line=R
Green Line=G=1 Foot
Applying trigonometry G/R=Cos XYZ,
R=G/Cos XYZ,
Cos 0.01=0.995004
R=1/0.995004=1.005021085
Time taken to travel this will be =1.005021085*1000000/800=1256.27[Calculated in Chrony]
As Chronys will Calculate in Fraction of 4 it will be 1260;
So Chrony will display velocity 1/1260=793.36 instead of showing 800 Fps
So The error is of 7 Fps For 0.01 Degree only
Fore more angle error will be more….
So the larger detection area will allways show less velocity may be 20-30 FPS...where as these
problems does not impact pipe chrony.Hence Pipe chrony is the Most accurate one
And it is practically impossible to shoot with zero degree variation

i guess in your calculation you meant the time taken to travel from A to B is 1.250 milliseconds.
if R=0.995004 and G=1.000000 then the corresponding velocity error is about 0.49% without getting the chrony in picture,which looks good. or if i consider your experimental 7fps low over the expected 800fps, then it translates to error of 0.875% low reading which is not too bad, where the chrony is contributing about than 1/3 of the error.
aligning the muzzle and the pipe chrony is equally tricky, on its own pipe chrony does not automatically guarantee to be perfectly aligned.


PS:this is not meant to downplay your efforts over the month in any way, rather something which sets me thinking loud.

[/quote][/quote]
No friend,I dint mind at all.just remember this error is for 0.01 degree alignment...and alignment can be in any axis...for 1 degree think how significant the error would be..if you want to test this thing.just fire through a F1 chrony by attaching Combro crony on muzzle..i am sure u will be surprised after seeing the result..just try it once ,
Then you will get the idea how small deviation in muzzle alignment which can not be judged by naked eye indulge in resulting significant error in reading

[ganeshn]

harshvardan thats great, what it tells me is that if i stick to my position on F1 crony then i need to tweak the inclination of the crony to match the ballistic path at that particular distance, if i ever want to get a true velocity.

[harshvardhan]

Yes my friend and you and me are not robot so holding a rifle with 0 degree inclination is not possible.f1 chrony is very accurate itself but its the user who is imperfect...so to cancel this impurity/imperfection it's better to use a pipe chrony atleast in the case of air rifle.
By the way I have made a chrony with wider capturing screen also..but my simpChrony is much accurate tested in science lab..its about 99% accurate compared to wider screnns accuracy of about93 to 95%.but I must say screen chronys are more convenient to use which makes it popular..Just like digital Blood pressure machines are popular in common people then manual one but doctors still trust the mercury Bp machines

[pratik_mahale]

harshvardan your theory is correct

but Basu’s statement is not supporting it

Thanks Harsha,
This is deadly accurate ballistic chrony ,being conceptualised and prepared by you.
I say this ,having tested the same shot with imported F1 light Chrony.
The data is found to be almost 99.9% same that of with imported chrony.
The difference of 1-2 fps was due to position of two chrony ,one after another against the same shot.
It does not require any light ,so very easy to use any time during 24 hrs.
I wish , if you make it commercially , many members will be benefited.
Very nice product.
Thanks again......

Basu

[harshvardhan]

harshvardan your theory is correct

but Basu’s statement is not supporting it

Thanks Harsha,
This is deadly accurate ballistic chrony ,being conceptualised and prepared by you.
I say this ,having tested the same shot with imported F1 light Chrony.
The data is found to be almost 99.9% same that of with imported chrony.
The difference of 1-2 fps was due to position of two chrony ,one after another against the same shot.
It does not require any light ,so very easy to use any time during 24 hrs.
I wish , if you make it commercially , many members will be benefited.
Very nice product.
Thanks again......

Basu

Dear Pratikji ,very intelligent question.
Knowing this could happen ,the correction factor is included in my formula
Before sending it tu Basuda it's incorporated...moreover imported f1 chronys ossilarators are fine tuned and clicks in every 0.5 microsecond...pratikji u r having both types like mine.one day just try to shoot through the screens attaching pipe chrony to muzzle...use heavy pellet in your IHP 35...just share the experience...I was also shocked when I tested I thought I have miscalculated something in formula,later discovered it's the angular deviation

[moulindu]

Hi
Harsha that was a very descriptive & informative post describing working principle of SimpChrony. I would like to suggest if 3 sensor chrony can be built say with sensors at point A, B & C, that way 3 velocities can be detected with single shot. Difference between A to B, B to C & A to C, thereby getting average of 3 velocities & also can be used get ballistic coefficient of a pellet. You can always have the luxury of 3 velocities by pressing for difference between each two sensors if you wish then avg & finally ballistic coefficient. I am doubtful about ballistic coefficient since the distance between 2 sensors will be too small to find out. I am sure you can work out something
Regards Moulindu

[SMJ]

Hello guys,I am not too well versed technically like some of the members here so must say that there is some amazing value add and learning to be had from you guys constantly Harshvardhan I really hope you can make your product commercially available as if the new proposed draft arms rules go through, this product will be invaluable to all Air Gunners!

[harshvardhan]

Hi
Harsha that was a very descriptive & informative post describing working principle of SimpChrony. I would like to suggest if 3 sensor chrony can be built say with sensors at point A, B & C, that way 3 velocities can be detected with single shot. Difference between A to B, B to C & A to C, thereby getting average of 3 velocities & also can be used get ballistic coefficient of a pellet. You can always have the luxury of 3 velocities by pressing for difference between each two sensors if you wish then avg & finally ballistic coefficient. I am doubtful about ballistic coefficient since the distance between 2 sensors will be too small to find out. I am sure you can work out something
Regards Moulindu

Dear Moulindu,
Its not a big deal to engage 3 pair of detection but then the chrony will be much longer ,So if not alligned correctly pellet may hit the side walls
I am working on that,
Moreover i have worked on the technology to display data on smart phone via blue tooth,prototype is showing some significant result i am attaching the image...Hope if I managed to get some more time ,this will further improve..

[GNV]

Pipe chrony and larger window chronies both have their advantages and disadvantages I think.
If utmost accuracy is required pipe chrony excels. And added advantage is it can be used indoors without any special lighting equipment. But it can be only used to measure MVs only and is pretty useless to use it down range. Even though a chrony like the shooting chrony may not be as accurate as a pipe chrony it can be used at what ever range you want and get reasonably accurate readings within that particular chrony's accuracy range. I don't think people who buy a chrony would use it just to measure MVs only. They would also want to measure the fps at various ranges to calculate how much energy is retained by various pellets at various ranges.

Regards,
GNV

[harshvardhan]

Pipe chrony and larger window chronies both have their advantages and disadvantages I think.
If utmost accuracy is required pipe chrony excels. And added advantage is it can be used indoors without any special lighting equipment. But it can be only used to measure MVs only and is pretty useless to use it down range. Even though a chrony like the shooting chrony may not be as accurate as a pipe chrony it can be used at what ever range you want and get reasonably accurate readings within that particular chrony's accuracy range. I don't think people who buy a chrony would use it just to measure MVs only. They would also want to measure the fps at various ranges to calculate how much energy is retained by various pellets at various ranges.

Regards,
GNV

Dear Friend,
For various range trusted software like Chair Gun From Hawke Optics ,which is verry effective is available...
Moreover Pipe Chronys are Best Suited for Air Rifles because of No blast propelltion to pellet means pellets are propelled through air pressure only not like firearm where Hot Gas creates problem to use in pipe chrony.For Fire arms we need wide screen chrony otherwise its very dangorus to shoot inside a pipe with a fire arm.
One more thing, in my previous posts i have explained ,how angular deviation incorporates error in reading,,And its practically impossible to shoot from a far distance and making the inclination minimum,
Wider chrony is very easy to use.But Pipe chrony is compact ,needs no external light...Takes shot after shot with ease..And its pocket friendly
For Air gunners in my view knowing correct Muzzle Value is needed..Retained Energy and velocity can be calculated If some one know the pellet
mass using the ChairGun and ChairGun Pro software,
Thank you GNV for your Valuable post

[Basu]

Dear Harsha,
Today I tested velocity of my all ARs in SimpChrony , a total of 45 shots at a go.
There was not a single shot that the SimpChrony missed.
Also there was not a single erratic reading found.
The datas of my ARs already mailed to you.

Basu

[harshvardhan]

Dear Harsha,
Today I tested velocity of my all ARs in SimpChrony , a total of 45 shots at a go.
There was not a single shot that the SimpChrony missed.
Also there was not a single erratic reading found.
The datas of my ARs already mailed to you.

Basu

This chronograph is designed with sensitivity adjustment for maximum responsiveness..so its triggers for very small deviation or passing of pellet,and its tuned in such a way that muzzle blast does not impact its operation.currently blue tooth module is under development..With this it will be more convenient to use,
Thank you Mr. Basu.

[AnandNair]

Very good work Harshvardhan.
What would be the cost of the end product? If it is fitted on to the barrel, can it be done on to a rifle like the precihole, or a competition rifle which has the front barrel weights/sights. My combro is lying in the junk box because it is simply too cumbersome to fit on to the barrel. May be a variable size clamping system would work.
keep up the good work.