Thread: Velocity Loss From Summer to Winter.

Originally Posted by R93

Sounds about right too me. I dont loose as much but do loose some. It works with helicopters as far as density goes well. Higher the air density the better the engine and blades perform. They bite better air causing resistence of sorts. Same with anything flying thru air.
I would look at another powder if your worried about it, but 2810 is still good enough for a 6.5 to 700 odd.

I am interest in this percieved drop off in bullet performance during the winter and I am not sure I have a proper handle on the problem.

I remember the Army lectures in particular the claim that the 'viscosity' of the atmosphere had quite a bearing on the performance of bullet/shell. I expect this is true, especially when you take the flight time of the shell.

Copied from the web...This 'sticky' property of the gas is called the 'viscosity' and it plays a large role in Aerodynamic drag.

Now if I understand it correctly bullets perform better in warm, moist, less dense air of the summer..... than the cold, dry, dense air of the winter.

Remembering the density altitude tables at flight school and when pulling loads out of the hills with under powered machine (for the job we used them for anyway) While the Cold, dry, dense air gave the blades more bite and the engine better performance

Now here comes the questions... Is it the density of this air that bleeds off bullet speed???. Could this cold, dry dense air be described as sticky????. Why are rotor blades so much more efficient in cold dry dense air.... is it because the air sticks to them and makes them more efficient???