Intercepting fighters

Your sources are wrong or inaccurate. I read through them quickly but they weren't very detailed on the effect of multiple fighters on air superiority. Because I don't want to sound like "hey I'm right, they are stupid" , I attached a small scenario to this post to convince you that the number of fighters on air superiority has a big influence on the interception chance.

In the scenario, there are 20 stealth bombers ready to bomb a city defended by 20 jet fighters on air superiority. Because the interception chance for stealth units is only 5%, you'd expect to see only one unit intercepted. If you'll do 20 bomb runs, you'll see that there occur 10 interception (of which you win 3) (random number that governs the result is saved in the savefile so you'll see the exact same results as I saw, if you wait a turn, you might observe different results).

The scenario is made with the editor of Civ3 Conquests v1.22 and uses the debug mode of the editor. It uses the standard rules.

RJ, I have played with your save and also created a debug scenario of my own to test this. I was amazed at how fast stealth units were shot down when given plenty of opposition; (regular bombers went VERY quickly). I must say, I am appalled at the "myths" on the internet -- especially this one I had regarding Civ!!

20 fighters on air superiority is not something you will typically encounter. Even if the AI has a lot of fighters (high level AI), then they will often have just moved them (not on Air Superiority) to counter your bombing raids and they die before they can be placed on Air superiority. This is probably the reason behind the "myths" that circulate through a (substantial?) part of the civ community.

I had a (modded) game once where a large (40-50 cities) deity level AI owned more than 100 fighters. I'm happy that I knew about the power of fighters in numbers before that game. But it is not something you need to know for most games.

As posted before in this thread, artillery or cruise missiles (depending on the situation) can be a way to get rid of the fighters. In the game mentioned above, i used an even more radical solution of nukes. I nuked him 5 times, my 2 allies 15 times each, funny game that was

Roland Johansen said:

20 fighters on air superiority is not something you will typically encounter. ...

Click to expand...

Ah, but 6 to 10 interceptors is Not so uncommon for the AI to encounter after they have started pummeling one of my cities. Now I know that my fighters will not only waste them, but will waste them quicker. Unfortunately, I will not be surprised when they do it; instead I will be chagrined if they do NOT.

Roland Johansen said:

I don't think that is entirely true. The Mobile Sam is an effective unit against the stealth bombers but a large number of jet fighters has a better chance to intercept stealth bombers. 6 jet fighters on air superiority also have a 26,5 % chance to attack (and often destroy) an attacking stealth bomber and 20 jet fighters on air superiority have a 64% chance to attack an attacking stealth bomber. Fighters are the only way to get your cities really save against bombers.

I personally think that the 5% interception chance of stealth units is too low. You need huge amounts of fighters too have a good chance too shoot them down.

Click to expand...

First of all, thanks to Roland Johansen for exact and very valuable information and thanks to all others for inspiring quiestions. This is very good thread.

Anyway, I have 2 questions for experts on Air combat

1, Roland, in the text quoted above you say that to reach 26,5% probability of attacking stalth bomber, you can put 6 jet fighters into city. But, if I understand well, if you want to maintain this probability for every other incoming bomber, you need another 6 fighters for each of them...while using 4 SAMs should do the same job for any(?) number of bombers, as they can fire multiple times in one turn. Is this true, or am I missing something?

2, I suppose that AS for fighters placed on a carrier works the same way as if they were based in city/airport. Is it correct? I ask because yesterday I observed situation when my carrier full with fighters on AS and placed just by my city (and thus in operational range of the fighters) offered no protection against bombing runs of my opponent. I never saw any interception in about 5 turns and in each turn there came 2 or 3 bombers. After that I moved carriers into city, woke the fighters, put them on AS and things went well. Don't you know if the intercepted-animation is diaplyed even if bomber survives? This could be perhaps the solution - fighters from carrier intercepted but never destroyed, then when in the city finished the poor damaged bombers.

I will appreciate any answers, thanks in advance.

The interception animation does show in the event that a bomber shoots down a fighter.

Also you would know because the unsuccessfull fighter would be destroyed.

sleepsy said:

First of all, thanks to Roland Johansen for exact and very valuable information and thanks to all others for inspiring quiestions. This is very good thread.

Anyway, I have 2 questions for experts on Air combat

Click to expand...

Uh, thank you. My information comes from other excellent threads where diehard civfanatics have done experiments on the effectiveness of interception. I'm sorry, but I can't find these threads at the moment.

sleepsy said:

1, Roland, in the text quoted above you say that to reach 26,5% probability of attacking stalth bomber, you can put 6 jet fighters into city. But, if I understand well, if you want to maintain this probability for every other incoming bomber, you need another 6 fighters for each of them...while using 4 SAMs should do the same job for any(?) number of bombers, as they can fire multiple times in one turn. Is this true, or am I missing something?

Click to expand...

Each fighter has a 5% chance to intercept a stealth bomber (if on AS). Each fighter can only intercept once per turn.
So if 6 fighters are present in a city, then each of them has a chance of
1- (0,95^6)= 26,5% to intercept a stealth bomber. Even if 5 of the 6 fighters have intercepted a bomber in that turn, the 6-th still has a 26,5% chance to intercept the next stealth bomber. If all 6 have performed an intercept mission, then the next bombers have nothing to fear.
(If fighters on AS get shot down or bombed on the ground, then the interception probability probably decreases. It does seem logical, but I've not seen any tests on this).

sleepsy said:

2, I suppose that AS for fighters placed on a carrier works the same way as if they were based in city/airport. Is it correct? I ask because yesterday I observed situation when my carrier full with fighters on AS and placed just by my city (and thus in operational range of the fighters) offered no protection against bombing runs of my opponent. I never saw any interception in about 5 turns and in each turn there came 2 or 3 bombers. After that I moved carriers into city, woke the fighters, put them on AS and things went well. Don't you know if the intercepted-animation is diaplyed even if bomber survives? This could be perhaps the solution - fighters from carrier intercepted but never destroyed, then when in the city finished the poor damaged bombers.

Click to expand...

Fighters on AS should work on a carrier. Maybe you forgot to put them on AS and had just loaded them on the carrier? Or maybe you just had some bad luck. Ordinary bombers will be intercepted by fighters very often as even one fighter has a 50% chance to intercept an ordinary bomber.

About the animations: you can activate and deactivate them in the preferences section of the game (CTRL-P from main map). If they are activated, then both won and lost interception missions should be displayed.

Roland Johansen said:

Each fighter has a 5% chance to intercept a stealth bomber (if on AS). Each fighter can only intercept once per turn.
So if 6 fighters are present in a city, then each of them has a chance of
1- (0,95^6)= 26,5% to intercept a stealth bomber. Even if 5 of the 6 fighters have intercepted a bomber in that turn, the 6-th still has a 26,5% chance to intercept the next stealth bomber. If all 6 have performed an intercept mission, then the next bombers have nothing to fear.
(If fighters on AS get shot down or bombed on the ground, then the interception probability probably decreases. It does seem logical, but I've not seen any tests on this).

Click to expand...

Hmm, maybe I do not quite understand the concept behind the interception. I believed that during bombing #1, every fighter makes its choice. Then there is 26,5% probability that one of them intercepts.

The points is what happens with fighters which decided not to intercept when bomber #2 comes. It is quite clear that the one who already intercepted goes for cofee this time and those who did not make their choice yet, will try now. But I believe that the fighters who decided to stay on ground, do not get their chance anymore. If it works this way, it realy seems that the chances to shoot down 2nd stealth bomber are lower, aren't they? Because the only ones who try to intercept now are the fighters who didn't have the chance to make the choice yet...

Roland Johansen said:

Fighters on AS should work on a carrier. Maybe you forgot to put them on AS and had just loaded them on the carrier? Or maybe you just had some bad luck. Ordinary bombers will be intercepted by fighters very often as even one fighter has a 50% chance to intercept an ordinary bomber.

About the animations: you can activate and deactivate them in the preferences section of the game (CTRL-P from main map). If they are activated, then both won and lost interception missions should be displayed.

Click to expand...

I made sure they were on AS, after few turns I even tried to give them AS order again, just to be sure. Still there was no change. It would be interesting to experiment, I just could watch those poor people suffer anymore. As you say - 50% chance is quite high and animations were ON. That's why I decided to bother other people here with that.

sleepsy said:

...what happens with fighters which decided not to intercept when bomber #2 comes. It is quite clear that the one who already intercepted goes for cofee this time and those who did not make their choice yet, will try now. But I believe that the fighters who decided to stay on ground, do not get their chance anymore. If it works this way, it realy seems that the chances to shoot down 2nd stealth bomber are lower, aren't they? Because the only ones who try to intercept now are the fighters who didn't have the chance to make the choice yet...

Click to expand...

That sounds right. When the second bomber arrives you now have 5 fighters available to intercept because the 6th one already had its chance. So the chance to intercept the 2nd bomber would be 1-(0.95^5)=22.62. Chances will continue to decrease after each interception, down to 5% for the last fighter that hasn't already flown.

Hmm, maybe I do not quite understand the concept behind the interception. I believed that during bombing #1, every fighter makes its choice. Then there is 26,5% probability that one of them intercepts.

The points is what happens with fighters which decided not to intercept when bomber #2 comes. It is quite clear that the one who already intercepted goes for cofee this time and those who did not make their choice yet, will try now. But I believe that the fighters who decided to stay on ground, do not get their chance anymore. If it works this way, it realy seems that the chances to shoot down 2nd stealth bomber are lower, aren't they? Because the only ones who try to intercept now are the fighters who didn't have the chance to make the choice yet...

Click to expand...

While this does sound logical, I don't think this is the way it works. I'm sure the fighters that have had a failed chance to intercept get a chance to intercept the next bomber. This I know because of a test I did with the game in debug mode. I gave the hostile AI a lot of bombers (more than the number of fighters I owned) and each and every fighter I owned got a chance to intercept.

I also don't think that the number of fighters that already got an intercept mission has an impact on the intercept chance of the remainder of the fighters. I think I would have noticed this behaviour (a decline in the intercept ratio as more and more bombers make their bombingrun). It is however a bit tedious to test this behaviour. The best way (I think) would be to create a mod with a very low intercept chance (1% or so) and let the AI have a lot of bombers (100 or so) and you have a city with a lot of fighters (100 or so) on air superiority. If your assumption is true, then the number of intercepted bombers among the first 50 would be significantly higher than the number of intercepted bombers among the latter 50.

I made sure they were on AS, after few turns I even tried to give them AS order again, just to be sure. Still there was no change. It would be interesting to experiment, I just could watch those poor people suffer anymore. As you say - 50% chance is quite high and animations were ON. That's why I decided to bother other people here with that.

Click to expand...

You made me curious and I therefore created a scenario in the editor and I noticed you were right!!!
However the fighters on air superiority become active after one turn.
In the attached scenario below (Conquest 1.22 debug mode), you'll see a carrierfleet with 12 jet fighters on air superiority. It you leave them there, they will be bombed to oblivion. But if you move them away this turn and into range again next turn, then the fighters on air superiority will shoot down the attacking bombers.

I think SLEEPSY is just saying: if one of your 6 fighters tries to intercept, that fighter is not considered when the next bomber arrives that turn, so the overall chance to intercept goes down slightly after each fighter is used.

Zandrew said:

I think SLEEPSY is just saying: if one of your 6 fighters tries to intercept, that fighter is not considered when the next bomber arrives that turn, so the overall chance to intercept goes down slightly after each fighter is used.

Click to expand...

I believe that he actually said that all the fighters that tried to intercept (succesfully or not) are not considered anymore in the probability to intercept for the next fighter. You think that only the fighter that actually intercepted a bomber is not considered anymore in the probability to intercept for the next fighter. I also know that that fighter cannot intercept another unit that turn, but I still think all fighters on air superiority are considered in the probability to intercept (even if they already have performed an intercept mission that turn). I don't think that the probability to intercept goes down (although the number of AS missions is limited by the number of fighters on AS).

To make sure how it works, the study I proposed in the previous post is needed.

Roland Johansen said:

While this does sound logical, I don't think this is the way it works. I'm sure the fighters that have had a failed chance to intercept get a chance to intercept the next bomber. This I know because of a test I did with the game in debug mode. I gave the hostile AI a lot of bombers (more than the number of fighters I owned) and each and every fighter I owned got a chance to intercept.

Click to expand...

You have convinced me.

Resume:
- fighter(s) who intercepted on any bomber, does not intercept any more
- the fighters who lost their intercept toss on incoming bomber, try again on the next one

Zandrew said:

When the second bomber arrives you now have 5 fighters available to intercept because the 6th one already had its chance. So the chance to intercept the 2nd bomber would be 1-(0.95^5)=22.62. Chances will continue to decrease after each interception, down to 5% for the last fighter that hasn't already flown.

Click to expand...

I believe this formula seems to be right. Looks like chances decrease from 26,5% to 5% for 6th fighter. 7th bomber has 0% chance to be intercepted because of no fighters left.

But I think things could be even more difficult - in the situation when all fighters decided not to intercept bomber 1, all the 6 fighters will try to go for bomber 2. You probably know what I mean - if no fighter intercepts a bomber, next bomber will be endangered by the same number of fighters as the previous one.

Roland Johansen said:

...I also don't think that the number of fighters that already got an intercept mission has an impact on the intercept chance of the remainder of the fighters...

Click to expand...

This is exactly the point.

If the chances remain inchanged then all 6 bombers have 26,5% chance to be downed. But this would be strange. I thing the more logical way is to calculate the intercept probability just in the time when bomber #x comes - taking into account the fighters who already intercepted previous bombers.

Zandrew said:

I think SLEEPSY is just saying: if one of your 6 fighters tries to intercept, that fighter is not considered when the next bomber arrives that turn, so the overall chance to intercept goes down slightly after each fighter is used.

Click to expand...

Unfortunately no - I used to believe that one fighter tries only once for any number of bombers. (I am ashamed for it now )

Roland Johansen said:

You made me curious and I therefore created a scenario in the editor and I noticed you were right!!!
However the fighters on air superiority become active after one turn.
In the attached scenario below (Conquest 1.22 debug mode), you'll see a carrierfleet with 12 jet fighters on air superiority. It you leave them there, they will be bombed to oblivion. But if you move them away this turn and into range again next turn, then the fighters on air superiority will shoot down the attacking bombers.

Click to expand...

I am very happy that you were able to observe this behavior too. I am not very experienced in scenario creating (never tried yet) and I will definitely play the one you created as soon as I get home.

It is strange, perhaps a bug...

Roland Johansen said:

I also don't think that the number of fighters that already got an intercept mission has an impact on the intercept chance of the remainder of the fighters. I think I would have noticed this behaviour (a decline in the intercept ratio as more and more bombers make their bombingrun). It is however a bit tedious to test this behaviour. The best way (I think) would be to create a mod with a very low intercept chance (1% or so) and let the AI have a lot of bombers (100 or so) and you have a city with a lot of fighters (100 or so) on air superiority. If your assumption is true, then the number of intercepted bombers among the first 50 would be significantly higher than the number of intercepted bombers among the latter 50.

Click to expand...

Okay, I have done a study. The thing I wanted to study was if:
1) The number of fighters that is on AS determines the interception probability
or
2) The number of fighters on AS that hasn't performed an AS mission yet determines the interception probability.

(We already know that a fighter can only intercept once per turn but we don't know if it will still contribute to the interception chance of the remaining fighters after that interception.)

The study shows that the more logical case, number 2 is true.

The details of the study:
I created a mod where the interception probability is 1% and gave the AI 100 fighters that had an attack rating of 1000. My attacking bombers had a defence of 0. This way each bombing run that would be intercepted would cause the bomber to be destroyed. This would make it easy to see the succesrate of the attacking bombers by looking at the number of surviving bombers. I gave the fighters 20 extra hps so that they would survive all bombing runs.

I attacked with 8 groups of 40 bombers. The numbers that were shot down are: 23, 18, 20, 11, 11, 8, 3, 1.

This decline (especially the steep decline with the last groups) shows the influence of the fact that less and less fighters are available to intercept the bombers.

Roland Johansen said:

Okay, I have done a study. The thing I wanted to study was if:
1) The number of fighters that is on AS determines the interception probability
or
2) The number of fighters on AS that hasn't performed an AS mission yet determines the interception probability.

(We already know that a fighter can only intercept once per turn but we don't know if it will still contribute to the interception chance of the remaining fighters after that interception.)

The study shows that the more logical case, number 2 is true.

The details of the study:
I created a mod where the interception probability is 1% and gave the AI 100 fighters that had an attack rating of 1000. My attacking bombers had a defence of 0. This way each bombing run that would be intercepted would cause the bomber to be destroyed. This would make it easy to see the succesrate of the attacking bombers by looking at the number of surviving bombers. I gave the fighters 20 extra hps so that they would survive all bombing runs.

I attacked with 8 groups of 40 bombers. The numbers that were shot down are: 23, 18, 20, 11, 11, 8, 3, 1.

This decline (especially the steep decline with the last groups) shows the influence of the fact that less and less fighters are available to intercept the bombers.

Click to expand...

Thank you realy for your effort with the study and the results you found out. Now the situation is quite clear.

Concerning the carrier problem, I already tried your scenario and it perfectly corresponds to what I observed during my current game. Fortunately, the fighters do intercept when meeting an enemy. If not, ships would be quite useless when facing aircafts (especialy with lethal sea bombardment ON) as the ship AA defences are relatively low. This way they can still be protected by carriers with fighters aboard.

I have created new thread on the fighter@carrier issue in C3C forum to get some more reactions from other people. I hope you don't mind I made a link to your beautiful 3-carrier scenario

Thank you for the compliment. It is a good thing to start a new thread about your observation as it is a not (widely) known problem.

About the game where you first noticed this behaviour:
Did you wake the fighters every turn and put them on AS again? I'm asking this because you tell us that you observed 4 turns of bombing without interception while in my test scenario the fighters would respond the second turn. I concluded that it takes a turn for the AS to kick in. But if you would reactivate the fighters every turn and put them on AS again, then they would never intercept. Was that the case in your game?

No, it wasn't that case. I took this into account and left the fighters for few turns withou my intervention.


It also came to my mind that there could be an effect of starting/initial turn in your scenario, when fighters perhaps do not act properly. In my game, I was the first to have Flight, so I made the fighters, put them onto carrier and gave them AS orders. Then, opponent invented flight, build bombers and started bombing runs. Perhaps it was this sequence of event, which resulted into the described behavior.

Yesterday evening I tried to repeat the same situation but I couldn't - I have no save from that time. When I loaded carrier later in game and brought it near the city, it worked fine.

So, you think that the conclusion that fighters on AS on carriers take a turn to activate is not true, but that the problem is more difficult? It seemed to be an explanation for the behaviour of the fighters in the testscenario.

It was just an idea - too complicated, perhaps. I don't know anymore I think that 1-turn-activation answer looks quite good...at least it explains your scenario. Definitely, I'll focus on this issue in my future games.

For now, I'll rather play C3C Mesopotamia hoping that there is not too many bombers.