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Amizaur · 07-17-05, 06:58 AM

SS-N-27 ASM range bug cause and possible solutions:

Well yesterday after going to bed I still though about it and couln't fall asleep until found the answer. Hint - launch simultaneously (from pause) two SS-N-27s, one set to 1nm (but don't forget to set shutdown range to max) and the other set to 100nm. Now disable the pause and observe both missiles :-).

The missile range in the game seems to be calculated differently from torpedo range. You may launch two torpedos at different speeds and both will go to max range (which is unrealistic anyway). But range of a missile seems to be calculated by flight time. Max range is divided by max speed and the result is a lifetime of a missile in the air. Which leads to a problem when you try to run a missile at less than max speed (as in case of SS-N-27). SS-N-27 fly at 500kts until enable, then speeds up to max 1933kts.

Now let's calculate. Missile max range from database is 300024m = 162nm. Missile Max Speed is 1933kts. 162/1933*3600 gives flight time of 301,7 seconds. The missile will live just so long.
Now let's check how long it will go at 500kts in this time. 500*301,7/3600 = 41,9nm... Looks familiar, isn't it ? This is range of SS-N-27 at a speed of 500kts. You can also get this number more simple - divide missile speed by it's max speed (500kts/1933kts) and the result (=0.25866) shows what part of max range will a missile fly at this speed. 0.25866 * 162nm = 41.9nm.

Same problem is also the cause of SS-N-27 max range at 1933kts to be also little smaller than 162nm - some of the precious flight time is spent at 500kts between launch and 1nm enable point.

So the method of calculating missile range by flight time in game engine is wrong. It causes the problem with SS-N-27 and many other problems potentially. Should be changed to same method as for torpedos, or like was used in SC (I don't remember problems with SS-N-27s in SC).

But this is serious change and I know it would dalay relase of 1.02 patch. So temporary solution could be different - redesign of the SS-N-27 missile to work similar like SS-N-27 ASW (launch a submunition).

Currently the SS-N-27 is ONE missile which is run at 500kts (0.258 of it's max speed) until enable, and later speed up to max 1933kts. Not very realistic. Mainly because you can activate the missile at 1nm and get fully supersonic Mach 3 SEASKIMMING flight for about 140nm !!! Crazy. There is no such missile with such capabilites, and even if was - it would burn itself from the heat of air friction.

As we all know in reality SS-N-27 is a two-stage missile. First stage similar to Tomahawk fly subsonic, close to target a second smaller supersonic stage separates and attacks the target (and the first stage continues in the direction of the target working as decoy). The supersonic stage is rocket propelled and have much smaller range.

Currently SUBROCs work very similar - first stage launches a torpedo. So let's make SS-N-27 this way. First stage will be subsonic with max speed of 500kts and range of 162nm (of course seaskimming, not ballistic like SUBROCS). At enable point it would launch second, supersonic stage with speed of 1933kts and proper range, the first stage could continue it's flight increasing number of targets for air defense to shoot at. Very realistic and working even without changing range calculating method (because we run each missile on it's max speed).

I think that making SS-N-27 to work this way would be much faster than changing range calcs in game code, and could be done in few hours to include in 1.02 patch.

For current 1.01 players - if you want your SS-N-27s to go long range, about 140nm, enable them as soon as possible (1nm) - so launch them manually, not from NAV screen. Unfortunatlely then they will fly whole 140nm at 1900kts which is TOTALLY unrealistic... but the only way to reach long range now.

Cheers!

07-17-05, 06:58 AM	#10
Amizaur Sonar Guy Join Date: Nov 2002 Location: Poland Posts: 398 Downloads: 0 Uploads: 0	SS-N-27 ASM range bug cause and possible solutions: Well yesterday after going to bed I still though about it and couln't fall asleep until found the answer. Hint - launch simultaneously (from pause) two SS-N-27s, one set to 1nm (but don't forget to set shutdown range to max) and the other set to 100nm. Now disable the pause and observe both missiles :-). The missile range in the game seems to be calculated differently from torpedo range. You may launch two torpedos at different speeds and both will go to max range (which is unrealistic anyway). But range of a missile seems to be calculated by flight time. Max range is divided by max speed and the result is a lifetime of a missile in the air. Which leads to a problem when you try to run a missile at less than max speed (as in case of SS-N-27). SS-N-27 fly at 500kts until enable, then speeds up to max 1933kts. Now let's calculate. Missile max range from database is 300024m = 162nm. Missile Max Speed is 1933kts. 162/19333600 gives flight time of 301,7 seconds. The missile will live just so long. Now let's check how long it will go at 500kts in this time. 500301,7/3600 = 41,9nm... Looks familiar, isn't it ? This is range of SS-N-27 at a speed of 500kts. You can also get this number more simple - divide missile speed by it's max speed (500kts/1933kts) and the result (=0.25866) shows what part of max range will a missile fly at this speed. 0.25866 * 162nm = 41.9nm. Same problem is also the cause of SS-N-27 max range at 1933kts to be also little smaller than 162nm - some of the precious flight time is spent at 500kts between launch and 1nm enable point. So the method of calculating missile range by flight time in game engine is wrong. It causes the problem with SS-N-27 and many other problems potentially. Should be changed to same method as for torpedos, or like was used in SC (I don't remember problems with SS-N-27s in SC). But this is serious change and I know it would dalay relase of 1.02 patch. So temporary solution could be different - redesign of the SS-N-27 missile to work similar like SS-N-27 ASW (launch a submunition). Currently the SS-N-27 is ONE missile which is run at 500kts (0.258 of it's max speed) until enable, and later speed up to max 1933kts. Not very realistic. Mainly because you can activate the missile at 1nm and get fully supersonic Mach 3 SEASKIMMING flight for about 140nm !!! Crazy. There is no such missile with such capabilites, and even if was - it would burn itself from the heat of air friction. As we all know in reality SS-N-27 is a two-stage missile. First stage similar to Tomahawk fly subsonic, close to target a second smaller supersonic stage separates and attacks the target (and the first stage continues in the direction of the target working as decoy). The supersonic stage is rocket propelled and have much smaller range. Currently SUBROCs work very similar - first stage launches a torpedo. So let's make SS-N-27 this way. First stage will be subsonic with max speed of 500kts and range of 162nm (of course seaskimming, not ballistic like SUBROCS). At enable point it would launch second, supersonic stage with speed of 1933kts and proper range, the first stage could continue it's flight increasing number of targets for air defense to shoot at. Very realistic and working even without changing range calculating method (because we run each missile on it's max speed). I think that making SS-N-27 to work this way would be much faster than changing range calcs in game code, and could be done in few hours to include in 1.02 patch. For current 1.01 players - if you want your SS-N-27s to go long range, about 140nm, enable them as soon as possible (1nm) - so launch them manually, not from NAV screen. Unfortunatlely then they will fly whole 140nm at 1900kts which is TOTALLY unrealistic... but the only way to reach long range now. Cheers!