[FIXED] Aircraft Fuel Disparity 1115.8.1

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Primarchx
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[FIXED] Aircraft Fuel Disparity 1115.8.1

Post by Primarchx »

I'm seeing aircraft flights where there is a large disparity in fuel states between members that took off at the same time and have been operating together ever since. Why would some members of a flight have different fuel consumption than another?



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DWReese
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by DWReese »

I've been reporting on this since Day 1. They have tried fixing it twice, and it has improved, but it's still broken.

The original problem occurred, I believe, when the pair gets sort of separated, and one plane has to make up ground. When one plane reaches the return point where he adjusts his altitude and speed, the other is still trying to catch up. When he does, the program never readjusts his altitude or speed. So, one plane is often at 36 k at 480 kts, while the other is at 200 ft and 520 ft. It burns fuel pretty quickly that way.

I've seen this mostly with groups that were originally involved in bombing attacks.

But, I don't believe that this issue is the same.

AndrewJ
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by AndrewJ »

I've noticed this too, and its more pronounced in CMO builds than older CMANO.

I think that in some cases it's because the lead aircraft is flying at constant speed, and others are trying to hold formation with it. As the lead turns at (for example) cruise speed, the plane on the outside of the turn has to speed up to military power to try and hold its relative position. It goes up to military power, consumes more fuel, catches up to its position, and then slows down to cruise again. Repeat at every corner and course change... Similarly, if the group reaches the end of a manually plotted course, and starts the "spin-in-place" behaviour, then one of the planes will constantly be trying to go faster to hold its position with respect to the eternally turning lead plane, and fuel consumption will be constantly higher.

Takeoff behaviour can also influence this, to a degree. If the lead is given a course immediately, before the entire group has launched and formed up, then trailing planes will have to consume more fuel as they try and catch up at higher speed. I see this most when I'm rushing fighters off a carrier, and immediately put the group on military power to make an intercept, so the wingman has to go to burner to catch up when he launches later.
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Primarchx
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Primarchx »

I checked for that in this sample. Both aircraft took off from an airbase at the same time and were at the same point, altitude and speed. Would the second aircraft really have to exert this much extra smash to keep in formation? Interesting. Appreciate the answers, thanks folks!
AndrewJ
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by AndrewJ »

Here's a little test scenario, using F-18Es. All of them have Ferry loadouts, and all are flying at the same altitude (36,000 feet) and speed (loiter). The database indicates they should have a fuel consumption of 24.42 kg/minute under these conditions. In this case I let them fly for 3 hr 46 min, until they've used a little over half their fuel, and I got the following results.

1) Single planes, straight line: Two individual F-18s are on a straight line course. Both are consuming at 24.4 kg/minute, according to their Unit Fuel display, and both have 5379.4 kg of fuel left on board. Calculated consumption rate is 24.47 kg/minute, which is almost exactly the same as the 24.42 kg/minute indicated in the database. All is well.

2) Group of planes, straight line: A group of two F-18s is on a straight line course. Both are consuming 24.4 kg/minute, according to the display, and actually consuming 24.47 kg/minute. The lead has 5379.4 kg of fuel left, the same as the individual planes, but the wingman only has 5371.4 kg of fuel, which is 8kg less. I assume the 8kg difference came from a little nudge on the throttles that the wingman did to get into his station.

3) Group of planes, box pattern: A group of two F-18s is on a support mission, flying a box pattern approximately 7 nm on a side. Both are consuming 24.4 kg/minute, according to their display, when they are on the straight side of the pattern. The lead has 5379.4 kg of fuel left, just like the planes flying straight. However, the wingman has only 4009.0 kg of fuel, having burned over a ton more fuel than his lead. You can see the wingman's fuel consumption jumping from 24.4 kg/min (loiter) to 52.5 kg/min (military) as it goes around each corner. The wingman's actual consumption (averaged over the time in flight) was 30.54 kg/minute. This is quite close to cruise speed consumption, but that is coincidental, and other tests show the actual number will vary based on the shape and size of the flight pattern.

4) Group of planes, circling: A group of two F-18s has no orders, and is circling in place. The lead is consuming 24.4 kg/minute, according to its individual Unit Fuel readout. The lead has 5379.4 kg left, again, just like the planes on straight line courses. The wingman is much worse off, with a mere 2250.2 kg of fuel remaining, having burned over three tons more than his lead. The wingman's actual fuel consumption (averaged over the time of flight) is 38.3 kg/minute. This is above cruise fuel consumption, but less than military power. It's Unit Fuel display flickers up and down between loiter (24.4 kg/min) and military (52.5 kg/min) consumption rates.


So to me, it looks like the game is calculating properly.

My question, since I am not a pilot, is whether flying in formations really does impose this sort of fuel consumption burden in actual practice? Do pilots really have to jump up to military power to keep pace when a loitering lead turns a corner? Or do both of them make more gradual throttle changes and allow fluid formation changes, with the result that fuel consumption is lower? (Maybe the guy on the outside swings to the inside, and vice versa?)


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Primarchx
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Primarchx »

I see. The group I posted had been point-orbiting for a while before I tasked them with an intercept. So the wingman had to use a bit more fuel to remain on station with respect to their lead during that orbit time. Got it. In fact it sounds like it's probably more efficient to have them patrol on a box circuit than to just have them circle in place, fuel-wise.
AndrewJ
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by AndrewJ »

Yes, that seems to be the case. The bigger the box (the longer the straight sides), the more efficient the patrol will be.

You can also make them get slightly better efficiency by setting the patrol to a figure eight shape, since in one of those turns the wingman will be on the inside, and won't have to speed up. (Theoretically in a four point figure eight the wingman would be on the inside on two of the corners, but because Command forces the wingman to attempt to stay on a rigid station, the wingman only achieves a loiter throttle turn on one of the four corners.)

You could also try setting patrols as a pair of single aircraft, in which case there will be no station keeping to eat up extra fuel. The wingman would effectively be in trail position. The downside would be that it would be difficult to ensure the pair are always close together, especially if they leave the patrol to intercept, and come back from different positions.

Two missions, one fractionally offset from each other in space, could accomplish something similar, although it would still be problematic to keep the two planes close together.


The more I fiddle with this the more I suspect that the AI's requirement for rigid station-keeping and military power in every corner isn't realistic. Allowing the wingman's station to float within a zone near the lead, and more gradual throttle changes (perhaps dropping the lead to refuelling speed during a loiter corner, or only taking the wingman to cruise) would result in more efficient behaviour.

Are there any pilots here who can comment? [:)]

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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Rory Noonan »

Logged for investigation.

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Dimitris
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Dimitris »

I saw a mention in another thread that CMO currently (B1121.4) does not exhibit this issue.

Is the problem still appearing in the current CMO public beta? If yes, is there anywhere a save for seeing it ?
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michaelm75au
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by michaelm75au »

The problem is with the last CMANO update, and not CMO???

It may be related to how the wingman seems to take to flying off on its own 'missions', and not keeping with the leader[&:]
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by AndrewJ »

The problem is originally with CMO, and the latest patch seems to have added to CMANO as well.
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by DWReese »

ORIGINAL: michaelm75au

The problem is with the last CMANO update, and not CMO???

It may be related to how the wingman seems to take to flying off on its own 'missions', and not keeping with the leader[&:]

Nope!!!

I totally disagree with you. That WAS AN original bug that existed when CMO was released. That one was sort of fixed with CMO.

The new problem with CMANO does not necessarily have anything at all to do with planes being separated, evading, bombing, or anything else. In fact, the two planes can be seen leaving the base in perfect harmony, with everything in sync. Then, usually after a way point, they will proceed on their new course and, as observed in the UNIT SCREEN, the two are still exactly the same, with the fuel rate also being the same, BUT the FUEL BAR with start changing rapidly AND the amount of remaining fuel for each will no longer be the same.

Don't be fooled into thinking that THIS error in CMANO has to do with catching up, or being separated from the wingman. It doesn't.

This error (which should be helpful) is the SAME as the very ORIGINAL CMO problem. It's as if the CMO code from November 15 (when CMO was released) was used in this new CMANO update.

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michaelm75au
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by michaelm75au »

Just watching a group in a mission from the above test in CMO, the leader flies along at 'loiter' and the wingman keeps switching between 'full' and 'loiter'?
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Dimitris
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Dimitris »

This is currently being looked on.
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Dimitris »

Okay, this is a tough one. It's basically a combination of "this is how things work in RL" and "some adjustments needed". Big thanks to AndrewJ for his very helpful save, with the parallel examples. This is what useful contribution looks like.

Throughout CMANO's lifetime, when it came to airgroups we stuck to an abstraction: That aircraft formations do not exist; every wingman simply sticks close to the lead without any order or direction.

In order to implement aircraft formations in CMO, this abstraction was broken down. Now wingmen have specific positions within the group and they need to stick to them, or else the player's intent is not followed. This is not much of a problem as long as the group flies straight. During turns, however, as formation positions rapidly shift around, wingmen need to move to them swiftly, throttling up as necessary. This is what is causing the differences in fuel consumption.

Now, there are certain cases where such aggressive maneuvering is unnecessary; for example, during initial group form-up, or when aimlessly loitering (no plotted course etc.), there is no point in setting up the group formation. But for most other cases, having the tactical formation in place can really mean the difference between victory/survival and failure/death. This also applies to situations where the group is not actively engaged but could be, e.g. a patrol leg: What if the enemy ambushes your airgroup while its cohesion is still broken up after a sharp turn?

So how do RL airgroups deal with this effect? They try to minimize it through "tactical turns" (coordinated group turns), designed to minimize the disruption window, and by setting conservative bingo/joker fuel thresholds so that the success of a mission does not hinge on whether wingman #3 burned a little more fuel than the others.

So, for the next update we are implementing some tweaks for cases such as group form-up, loiter etc., and also trying to optimize group behavior during turns to minimize the time period during which the wingmen are out of position. This can include having the lead slow down (so that everyone else catches up faster), but this can very easily turn out a double-edged blade: "The group was intercepted as it was egressing the target area, because the lead slowed down so that the rest of the group could catch up".

Thanks.
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SeaQueen
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RE: [Logged] Aircraft Fuel Disparity 1115.8.1

Post by SeaQueen »

ORIGINAL: Primarchx
I'm seeing aircraft flights where there is a large disparity in fuel states between members that took off at the same time and have been operating together ever since. Why would some members of a flight have different fuel consumption than another?

Lots of reasons. The wingman's job is to keep up. The flight lead's job is to call the shots. The result is that wingmen may often be at higher throttle settings for longer periods of time during many maneuvers in order to maintain their position. There is such a thing as tactical turns, which have the effect of keeping aircraft in their formation more efficiently, although sometimes their positions end up reversed. Those include things like hook turns, delayed turns, shackle and crossover turns. It's all geometry. You can find information about that stuff on the internet and in flight simulator manuals. Falcon BMS has some nice ones for that kind of stuff. There's also T-38 and T-45 manuals available on the internet I believe. Those aren't reflected in C:MO. I'm okay with that though, because it'd be equally unrealistic to see massed aircraft maneuvering around in rigid formation like some kind of Nazi air show. Sometimes the simple solution (Hey! you! bump up your power!) is the way to go. Real flight leads, if they're good, will call out their airspeed and altitude to their wingman now and then (although they're not obligated to!) in order to make the wingman's job a little easier.

Sometimes formations are also more loosely defined than others (e.g. fighting wing) where the wingman maneuvers in a cone behind the flight lead. Others are very rigidly defined (think Thunderbirds). Different formations suggest different tactics and have trade offs. In real life, aircraft are typically much more spread out than even how people in the flight simulator community tend to fly, which is basically fingertip formation. It's good for learning how to fly precisely but offers few tactical advantages. Spreading out offers some sensor advantages (both from an employment and detection perspective) and allows better mutual support. One of the down sides of spread out formations is that if the lead makes a small turn, the wingmen all have to make big adjustments in their position.

Another part of the solution is in planning around JOKER fuel so that nobody is so low on gas that they can't continue.
DWReese
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by DWReese »

This described problem was somehow transferred into CMANO.
AndrewJ
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by AndrewJ »

Perhaps an option to "Enforce rigid formation" or not, rather like the 'group lead can slow down to reform' option, would be a useful way to solve this? Then the player could either have fluid formations, like legacy CMANO, or rigid ones where the situation warrants it.

After all, what's one more check box! [:D]
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by Dimitris »

Tweaked the behaviors in B1121.5 .
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RE: Aircraft Fuel Disparity [b. 1115.8.1]

Post by DWReese »

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