About the behavior of AI planes in taking off

[Alfaunostebas11]

I would like to ask you for an explanation about the behavior of the A.I. planes, as they take off, starting from a parking position.

Now, I'm having trouble with a flight of six Ju-87s, where the player is no. 4 in formation. The Leader plane move and taxi to the runway, followed by nr. 2 e 3. I take a position next to nr. 3 and slightly behind (taking care not to overtake it ...?). So I'm waiting for the nr. 5 and no. 6 take position. All have their navigation lights on, signaling their willingness to take off.

One by one the various planes send an (automatic) message of readiness for take-off. At this point what I don't understand happens.

If all is right, the leader starts the take-off run, after a few seconds ... sometimes after several minutes ... but sometimes never ... My question is: when is the time for the leader to start the take-off run?

It would seem that the leader still waits for something before taking off ... But, the runway is clear and there are no landing authorizations for other flights ...

I specify that my logic provides that the Command Take-off and the Waypoint 1 are activated simultaneously by a Begin >>> Timer 2 sec. >>> TL. And that the Advanced properties of the leader have an Event >>> On Plane Took Off >>> WP 1. The WP1 naturally has an OL with the player.

So how is the timing established? Is it useful (as well as aesthetically) to put a green flare? Is the position on the track of the player crucial who (unlike the other wingmen) does not have the possibility to send a message "ready for take-off" ...?

Thanks.

Edited November 16, 2021 by Alfaunostebas11

[JimTM]

I wonder if it has something to do with the position of the last plane or two with respect to the last taxi point versus the first VPP point on the runway. Maybe the last few planes are closer to the last taxi point than they are to the VPP point so they may still want to taxi further. Try moving the VPP a little further down the runway (not too far) or the last taxi point a little further back.

[Alfaunostebas11]

Jim, as always, your experience is a winner and your advice is valuable ...

I solved the problem by even eliminating the last taxi waypoint before the VPP and now all six planes are stopped on the runway very close to the VPP and well ahead the last taxii WP.

As soon as the no. 6 sends the message "ready", the Leader begins his race ...?

Thanks Jim, I will definitely bother you again ...

[JimTM]

I'm glad that the adjustment solved your problem Alfaunostebas11. No bother at all.  

[IckyATLAS]

I made a lot of tests regarding the problems with large AI flights takeoff procedure when they have to taxi to the runway. Here my findings and comments on the behavior but as usual the real internal workings of the scripted actions will remain as usual mysterious.

The planes in a flight will automatically position themselves according to the leader which will go to the takeoff VPP point.

The positioning of the planes is easier for fighters that are smaller in size than the bombers. First a fighter reacts quicker to engine power change compared to a bomber or a biplane, so not only the bomber is slower to move and it also is larger so it will be nearer to each other on the runway.  It seems that the AI does not make a difference between planes size and the way the takeoff positions of each plane are geometrically defined behind the leader for which we have no control. The more planes are in a flight and the longer it takes to have all the planes in the flight behind the leader ready for takeoff, because the planes will take more time to be in the right position and orientation.

 

The AI seems to control the power of the AI planes according to the distance to their virtual (I say virtual because it is defined by AI and not us) target takeoff point on the runway. AI tries to avoid collisions between AI planes or against the player plane. This would also explain why for bombers the motions to position themselves are smaller than with fighters, because the AI tries to avoid collisions between AI planes and so will reduce even more the power to move as it cannot change altitude all the planes are in a unique 2D plane that is the runway. On the runway as the virtual takeoff points do not consider bomber size, the bombers become very near to each other and risk of collision increases hence smaller and smaller movements. This can go to complete blockage or excruciatingly long timings before takeoff. I had also the case of a complete blockage (never took off)  with only two U2 biplanes with max load of bombs. As you know the U2 biplane is very underpowered so he moves very slowly has a lot of inertia. The second never was able to get perfectly on its takeoff position. So in my mission with U2's I do not use the full load of bombs but half load to avoid this problem if a player wants to do a full AI takeoff. 

 

Nevertheless as Jim mentioned the VPP point for the leader has to be positioned according to the size of the whole flight otherwise some planes will stay stuck on the taxiway waiting and the takeoff will never happen, or they will fly form where they are and chaos again.  The larger the flight and the more the VPP point has to be further out on the runway. This can be a problem with large flights of heavy bombers that need a lot of runway to takeoff because you may eat a good portion of the runway just to position the flight. The leader will not have enough runway and start rolling on dirt which may slow him down even more. Take also in consideration when setting taxi points for the leader, that the following plane will only move if the taxi point in front of him is free. So if you have two taxi points that are very distant from each other the planes behind will wait until the distant taxi point is free, and this will also lengthen considerably the time needed to have all planes ready for takeoff. There are also other considerations when defining complex taxi paths and distances between taxi points to avoid chaos in the taxiing of the planes but this is not the topic here.

 

It is clear that improvements have to be made on the whole taxi path design and process but this is not a priority for devs except if they need it, but we never know when. 

There may have been a slight improvement on this in the late updates compared to before, that should either avoid the complete blockage or shorten the positioning time but I have not checked it in detail.

[Alfaunostebas11]

Hi Icky.

Your considerations, dictated directly by experience, are very interesting and surely understandable.

There are several situations and parameters that must be taken into consideration, even if in the end, as you say, the whole procedure currently has limits that affect the behavior of the A.I. which, therefore, sometimes remains mysterious ...

Thank you, for sharing your experience.