Jump to content

[SOLVED] Simulate rocket flight - airFriction correction - thrust in CfgAmmo is equal to acceleration

Recommended Posts

I am not sure your airfriction formular is right. In the real world airfriction is linear in terms if v, not inverse and squared.

I am using Fdrag = _airFriction*(vectorMagnitude _weaponVelocity) and that fits bombs and missiles well ingame (exept a small numerical factor).


okay, it turns out that my formula is correct for bullets of rifles and pistols only.


air friction of rockets (infantry tested only) has a much bigger positiv value than the small negativ value of air friction of rifle bullets.


thats documented nowhere :-(


So i ll try your formula for rockets then.


Could someone do the wiki entry for my prior post (thrust is equal to acceleration) please or tell me how I can get a wiki account because i have no register link there. i can only see a login link at wiki. 

Share this post

Link to post
Share on other sites

I dont know if anyone is still interested in this topic but maybe in future.


I did not find a formula to use the airfriction from missiles/rockets to get a good result of deceleration/speed.


but after calculating with some recorded data from NLAW, titan AT an titan AA ammo I got a value which can be hardcoded to calculate an airfriction value which van be used with the formula airfriction = a/v² which is described in the wiki.


If you multiply the positiv airfriction value from CfgAmmo, in case of NLAW its 0.4, with this factor:




then u will get an airfriction value of -0.00083204

and I promise, that is the airfriction of NLAW which the game uses in the formula airfriction = a/v².

Maybe there is a very little mistake in that hardcoded factor´but it works really nice to calculate current deceleration from current speed.


All I said is tested for NLAW, Titan AT an Titan AA only. But I ll test more self propelled weapons within the next weeks

  • Like 1

Share this post

Link to post
Share on other sites

I did some more tests with RPG, DAGR, and ASRAM.

I wrote a script to calculate air friction (f) on each frame for the not propelled flight time (after rocket Motor is burned out) and give me the average value of air friction.

Again I used this formula to calculate air friction:

f= a/v²

It turnes out that air friction does not depend on acceleration and velocity only. it seems to depend on the shooting angle and something (odd) else, too.

For my tests I ve chosen a angle of round about 0 degree and a combat range between 1 and 3.5 km depending on weapon type (e.g. NLAW 2 km / RPG 1 km / ASRAM 3.5 km) 

Up to now I would say that -0.002 is a good value for that desired factor.


One who wants to get the current acceleration of a self propelled bullet could use:


a = v² * f * (-0.002)


for a non self propelled bullet one should use this as documented in wiki:


a = v² * f


f is the airFriction value from CfgAmmo and v the current speed of the bullet.

  • Thanks 2

Share this post

Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now