Recent content by Jim Hahn

ERROR. I made a mistake in my formula. I wrote that BC = 1/4 times ... The 1/4 should not be there. The coefficient is ONE. Apologies....

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Two more chunks. Scanner acting up...

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Split into several sets of pages. To allow me to post as attachments. Several 'chunks'. Should learn how to use Dropbox...

Ran into attachment size limit. Very small. Send me an email and I'll forward to you. "hahn" underscore "02493" atSign "yahoo.com"

Did not scan it yet. Wasn't sure anybody was interested. Will scan and post, probably today.

Derivation's available. 10 pages, hand written, scanned.

Several places on the Internet reference the following equation for calculating BC: $$G1 = 0.0052834 * \frac{L}{\sqrt{V_0}-\sqrt{V_L}}$$ Unfortunately, the equation seems to have raised many questions and confusion on how to use the equation. I derived the more useful, and less confusing...

Info: Retired. Long range rifle shooter. 35 years writing software for computer operated equipment, mostly in 'c'. Live in Arizona.

Several different sites, including PhysicsForums, mention/discuss a formula for computing a bullet's Ballistic Coefficient based on measuring two downrange velocities where the measurements are made a distance L between them. This can be done with traditional skyscreen (optical) chronographs or...

I have been working on the derivation of this formula for several weeks. I can get the form of "L/difference of square roots of velocities." Not there yet on the multiplier. The formula is based on recognizing that the drag vs Mach number curve has several sections. Low velocity is constant...