Hunting Washington Forum

Big Game Hunting => Bow Hunting => Topic started by: konrad on January 31, 2010, 11:51:49 AM

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Title: Lost Pinwheel User
Post by: konrad on January 31, 2010, 11:51:49 AM

I am trying to find the fellow out there running Pinwheel software who was kind enough to run some numbers on my set-up. We were discussing shafts required to produce a FOC of 19%.

I seem to have forgotten what thread he was lurking about in.

Thanks for your prompt response!

Konrad


PS   
A: Easton Technical’s program gave me the 2413 shaft size for my current configuration (which works admirably).
B: To answer your question, Yes, I have read almost all of Dr. Ashby’s work and find it to be invaluable.



Thanks again,
KL

Title: Re: Lost Pinwheel User
Post by: bonkellekter on January 31, 2010, 11:59:03 AM

It was TODD ID in the archery forum - I believe the thread was titled - An Offer to Help - Thanks to his post I purchased the software too so if you would like I can run numbers for you as well.

Title: Re: Lost Pinwheel User
Post by: jackelope on January 31, 2010, 12:05:46 PM

it was Todd

http://hunting-washington.com/smf/index.php?action=profile;u=1158 (http://hunting-washington.com/smf/index.php?action=profile;u=1158)

Title: Re: Lost Pinwheel User
Post by: konrad on January 31, 2010, 10:14:18 PM

Thanks Guys!

I'll be sure to contact him there.

My rig is an 07 Bear Truth, draw weight 60 pounds, draw length 27 inches and a 29 inch shaft using a mechanical release.

I wanted to know what arrow spine and tip weight would give me a 19% FOC balance point

Title: Re: Lost Pinwheel User
Post by: Todd_ID on February 01, 2010, 07:52:51 AM

http://hunting-washington.com/smf/index.php/topic,43087.msg521240.html#msg521240 (http://hunting-washington.com/smf/index.php/topic,43087.msg521240.html#msg521240)

Here's the info that the program spit out for you.  Let me know if there's anything else you are needing to know.

Title: Re: Lost Pinwheel User
Post by: xXx Archery on February 01, 2010, 08:49:48 AM

Quote from: konrad on January 31, 2010, 10:14:18 PM

Thanks Guys!

I'll be sure to contact him there.

My rig is an 07 Bear Truth, draw weight 60 pounds, draw length 27 inches and a 29 inch shaft using a mechanical release.

I wanted to know what arrow spine and tip weight would give me a 19% FOC balance point

Are you sure about your Draw?     draw length is measured from the string at full draw to the deepest part of the grip and then ADD 1.75" ...27" is short in a other post you said you are shooting 240fps with 490grain arrow so I ran some #'s

Total Arrow Weight: 490
Bow IBO Speed: 317   
Adjustment for Draw Length: -30    at 27" of draw
Adjustment for Draw Weight: -20    At 60lbs
Adjustment for Arrow Weight: -47
Adjustment for Weight on String: -3

Calculated Speed: 217 fps
Kinetic Energy: 51.25

now at 29" of Draw

Total Arrow Weight: 490
Bow IBO Speed: 317
Adjustment for Draw Length: -10
Adjustment for Draw Weight: -20
Adjustment for Arrow Weight: -47
Adjustment for Weight on String: -3

Calculated Speed: 237 fps  This is more inline with what you said you are shooting
Kinetic Energy: 61.13

Title: Re: Lost Pinwheel User
Post by: konrad on February 01, 2010, 08:01:05 PM

I started with the 29 inch draw module and have dropped down two. The old Sportsman's Warehouse chrono said  236 to 241 over six shots.
Maybe they needed new batteries???

Title: Re: Lost Pinwheel User
Post by: Todd_ID on February 02, 2010, 08:53:24 AM

I'd say that their chrono is more accurate than the software predictions we're offering here.  Mabye the draw weight is a little more than 60#?  Maybe the draw length is a bit longer than the modules say (quite common for a 30" module to be 30.75" draw, for example).  If you were using the software and massaging the input to match your stuff exactly, then I think the numbers would be much more precise.