# Latest Experimental build, what's new?

**URL:** <https://discourse.cataclysmdda.org/t/latest-experimental-build-whats-new/17835>\
**Category:** The Bunker\
**Created:** [December 9, 2018, 11:34pm UTC](https://discourse.cataclysmdda.org/t/latest-experimental-build-whats-new/17835 "2018-12-09T23:34:59Z")\
**Posts on this page:** 1\
**Showing post:** 38

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**Author:** ![mlangsdorf](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.cataclysmdda.org/mlangsdorf/32/2462_2.png) [@mlangsdorf](https://discourse.cataclysmdda.org/u/mlangsdorf)\
**Post date:** [December 11, 2018, 10:33pm UTC](https://discourse.cataclysmdda.org/t/latest-experimental-build-whats-new/17835/38 "2018-12-11T22:33:17Z")

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base co-efficient of air drag (CoD) is calculated by going down each column of the vehicle and taking the highest value. each column starts at 0.25, +0.1 for having rams, +0.2 for not having half-boards in front of full-boards, +0.3 for not having windshields in front of seats, +0.3 for not having roofs over seats, +0.3 for having turrets, -0.1 for being twice as long as the vehicle is wide. So basically, the aerodynamics of a tank are terrible and you’re looking at a base CoD around 1.0.

Effective CoD is multiplied by an approximation of the vehicle width in meters and an approximation of the vehicle height - 1.4m for motorcycles, +0.6 for having aisles, +0.5 for having fullboards, +0.1 for having roofs, so your tank is probably about 3m wide and 2.5m tall and you’ve got an effective CoD of 7.5. Compare that to a sports car, which has a base CoD of 0.25 or so, a width of ~2m, and a height of 1.5m, for an effective CoD around 0.75.

Air drag is proportional to the square of velocity times effective CoD, which is one of the reasons a sports car can reach 175mph with a single V12 and 3 v8s get a light tank to 51 mph. The other reasons include the tank massing 20x as much as the sports car and having at least 20x the rolling resistance.

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