Talk:Ballistic coefficient

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[edit] Equation oddities

Why use "w" for mass? (Perhaps m would be better) Why use "d" for diameter, then in the very next equation, use "d" for "average density"? (Perhaps use Greek rho or k for the density) Why bother to equate the term mass / area as equal to average density * length (Only correct for objects with constant cross section. For other shapes this relation is an approximation, not an equality.) —Preceding unsigned comment added by Matt in tx (talk • contribs) 05:21, 6 February 2008 (UTC)


Maybe a list with common ammunition types / bullets would be not bad. - Jack's Revenge 20:28, 23 July 2006 (UTC)

[edit] Winchester Advertisement?

The part on the .270 Winchester sounds like an ad. Rather than talking about cartridges, individual bullets should be mentioned (caliber and weight) with a range of BCs available by the common manufacturers (Sierra, Speer, Hornady, Lapua, Berger, ...)

Like... Caliber / Weight / Common BC range 6.5mm / 130gr / 0.495-0.571 6.5mm / 140gr /......

Possibly more of an addition to a "list" page.

Or shrink it down to the 5 calibers with the highest BCs by common manufacturers and the 5 calibers with the lowest BCs by common manufacturers.

[edit] Launch vehicles

Would it make sense to add a section discussing rocket launches? Isn't the reason a rocket is shaped like a bullet because that optimizes the ballistic coefficient? Also, in both cases is there a tie-in with the center of gravity/center of propulsion concept that could be covered? Sdsds 18:56, 26 March 2007 (UTC)

The main reason a lot of launch vehicles are tall and narrow is for transportation reasons. If they made the vehicle wider then they wouldn't be able to deliver it from the factory to the launch site. Other than that, aerolosses during ascent are inversely proportional to ballistic coefficient, which in turn is essentially proportional to vehicle length. For a dense-fuelled vehicle about 20m long there are roughly 300 m/s losses. For liquid hydrogen stages, the vehicles need to be proportionately longer, because the density of the vehicle is lower.WolfKeeper 19:45, 26 March 2007 (UTC)

[edit] Entire thrust of the article too pointed toward projectile ballistics?

This description of the general aerodynamic concept of the "Ballistic Coefficient" seems very strongly pointed toward the sub-genre of projectile ballistics. Suggest moving all the rifle+bullet stuff to another article (perhaps referenced as application examples) so the basic concept can be clearly seen, out of any clutter. With a good understanding of the basic concept, all the bullet observations should make sense. I'm not so sure you can easily go from a laundry list of interesting bullet trajectory observations to an understanding of the basic concept, however. Matt in tx (talk) 05:43, 6 February 2008 (UTC)

[edit] Heat during reentry

Wouldn't a higher BC reduce heat during entry into earth's atmosphere? —Preceding unsigned comment added by 71.112.78.96 (talk) 23:24, 31 March 2008 (UTC)

Nah. It takes longer to slow down.- (User) WolfKeeper (Talk) 01:12, 1 April 2008 (UTC)