Refueling behavior question

[Joe K]

Are there cases where a tanker or tankers are not supposed to break off after completing re-fueling?

 

I'm curious because most times, after completion of re-fueling, a dialog will appear asking whether to separate the tankers from the group... but sometimes, this dialog does not occur, and the tanker(s) remain attached to the group. I'm wondering whether this is a normal occurance, due to some special circumstances, or if it may be a bug that I should attempt to capture?

 

I've had this happen every so often, but I don't see any particular difference from the cases where the tanker-separation dialog does appear, so I'm curious what may be the reason for this. (Incidentally, in the cases where the separation dialog hasn't appeared, it has usually resulted in the eventual loss of the re-fueled group, due to running out of fuel - even though there should have been plenty of fuel after the re-fueling. This may imply that the re-fueling actually never took place - even though the report window showed that the tanker no longer had re-fueling stores).

 

For example, yesterday, I lost 24 F/A-18s after launching them, along with a KA-6 tanker, at a carrier group that was nearly at the limit of their un-refueled range (I think the numbers were 1168 nm range, and 1026 sepration between the carrier groups). So, I threw in my only tanker "just to be safe". However, as the group reached its attack point, I noticed that the tanker was still attached, yet the report showed that it had no re-fuel stores. The group completed its attack and turned back but the tanker remained attached. The fuel range circle indicated at that time that there was still enough fuel to reach base. I then became distracted by other engagements, and next thing I knew, there was a report of 24 F/A-18s running out of fuel and crashing - about 150 nm from their carrier. So, apparently, including the tanker didn't ensure there was enough fuel. I wonder whether the re-fueling process was interrupted by the attack itself, although the group report already showed no re-fuel stores awhile before the weapons launch point, so...??? Oddly enough, I had launched my other 24 F/A-18s at the same target shortly after the large group, but in two groups of 12 planes each, with no tankers... and those groups got back with plenty of of fuel to spare, despite not being re-fueled at all. Rather puzzling.

 

Anyway, if this is normal behavior, please explain what's going on (so I can avoid getting myself into trouble in the future)... or let me know if it's not normal, and I'll try to capture an example situation for examination.

 

Thanks.

[wombat1417]

It's "normal" in the sense that it does, as you mentioned, happen from time to time. Is there any good reason for an empty tanker to remain with a group, none that I can think of. Even if the way home is through perilous airspace, it would make more sense to detail a couple of fighters as an escort than to have it tag along.

The problem I see most often is when after a refueling is done and you approve the split, your RTB options do not include the carrier you launched from, but airfields hundreds of miles away.

Tanker ops have always seemed to be on the hinky side, so much so that I try to avoid using them at all.

[CV32]

For example, yesterday, I lost 24 F/A-18s after launching them, along with a KA-6 tanker, at a carrier group that was nearly at the limit of their un-refueled range ...

 

Two observations:

 

1. Your aircraft groups are probably too large and unwieldy to be useful.

2. A single KA-6D has very little fuel to offer to a group of 24x recipients.

[Warhorse64]

I'm not sure why the tanker would have stayed with the strikers, that sounds like a game glitch, for sure. However, given that it did, it's not surprising that you lost the F-18s. F-18s cruise at 490 kts, where as A-6s cruise at about 415 kts, IIRC. A mixed formation will always fly at the speed of the slowest unit in the formation. Unfortunately, aircraft burn fuel at the same rate for a given throttle setting, regardless of their speed. That is, the F-18s will use the same amount of fuel per hour whether they are flying at 490 kts or 415 kts, because both are within the 'cruise' throttle setting. So for the sake of discussion, if the carrier was 470 nm distant when the F-18s turned for home, and the F-18s had one hour of fuel left, the range circle, calculating on the basis of their normal speed of 490 kts, would say you had enough fuel to get home, because 1 hr * 490 kts = 490 nm. However, if the F-18s were forced by the presence of the tanker to only fly at 415 kts, they still only have one hour of fuel left, which means they run out after 415 nm, a full 55 nm short of the carrier. That's what happened to you. I hope I've stated this clearly?

[Desertfox]

Tanker operations comments from one that mostly tries to avoid them (too much micromanagement although it has improved in the more recent versions).

- A tanker can only refuel somewhere around 4 aircraft and that's a REAL tanker like a KC-135. A KA-6 is only going to be good for 1 or 2 planes. It is best to fly missions that will need refueling in groups of 4 or less.

- Don't fly the tanker(s) with the strike mission. Fly them out to a rendezvous point where they will meet. If the tankers are slower than the mission aircraft or they are taking off from a more distant airfield, they will need to be launched first. And after refueling, split the tanker(s) off again. Either when the SA asks you to. Or by using the split group command. So that the mission aircraft can fly at their best speed and range.

 

The numbers that you reported for range don't seem to add up. If the loadout for the mission planes has a range of 1168 nm, then that's total flying distance. There and back. So the maximum range to a target is half that or a bit less. Say around 550 nm. If the distance to the target was around 1000 nm then it was too far. Almost the entire fuel load was used up to get there (and only if all at cruise speed) and a refuel would be mandatory either right before or right after hitting the target. So the tankers would have to go all the way to the target too. Almost. A risky mission plan even with enough tankers for the number of planes.

In Real Life (referred to as RL around here I believe), such a mission would need one refuel on the way to the target, and one on the way back. Which I really try to avoid as it takes more planning than I usually want to get into. Or more tankers than I have available.

[donaldseadog]

Are there cases where a tanker or tankers are not supposed to break off after completing re-fueling?

I'm curious because most times, after completion of re-fueling, a dialog will appear asking whether to separate the tankers from the group... but sometimes, this dialog does not occur, and the tanker(s) remain attached to the group. I'm wondering whether this is a normal occurance, due to some special circumstances, or if it may be a bug that I should attempt to capture?

Not so far as I know, Tankers should break off after refuel. However the refuelling process can take many minutes, it certainly isn't over as soon as the recipients have their fuel. If there are more than one unit being refilled or a large number of planes IFR can take more than ten minutes from memory.

I've had this happen every so often, but I don't see any particular difference from the cases where the tanker-separation dialog does appear, so I'm curious what may be the reason for this. (Incidentally, in the cases where the separation dialog hasn't appeared, it has usually resulted in the eventual loss of the re-fueled group, due to running out of fuel - even though there should have been plenty of fuel after the re-fueling. This may imply that the re-fueling actually never took place - even though the report window showed that the tanker no longer had re-fueling stores).

 

For example, yesterday, I lost 24 F/A-18s after launching them, along with a KA-6 tanker, at a carrier group that was nearly at the limit of their un-refueled range (I think the numbers were 1168 nm range, and 1026 sepration between the carrier groups). So, I threw in my only tanker "just to be safe". However, as the group reached its attack point, I noticed that the tanker was still attached, yet the report showed that it had no re-fuel stores. The group completed its attack and turned back but the tanker remained attached. The fuel range circle indicated at that time that there was still enough fuel to reach base. I then became distracted by other engagements, and next thing I knew, there was a report of 24 F/A-18s running out of fuel and crashing - about 150 nm from their carrier. So, apparently, including the tanker didn't ensure there was enough fuel. I wonder whether the re-fueling process was interrupted by the attack itself, although the group report already showed no re-fuel stores awhile before the weapons launch point, so...??? Oddly enough, I had launched my other 24 F/A-18s at the same target shortly after the large group, but in two groups of 12 planes each, with no tankers... and those groups got back with plenty of of fuel to spare, despite not being re-fueled at all. Rather puzzling.

 

Refuelling 24 hornets from one KA-6 is unknown territory to me so maybe it does cause some problem.

I'm not sure what your flight plan was, were you conducting a strike (you mention completing an attack) or were you ferrying (you mention separation distance from two carrier groups). Normally you can't 'launch' unless you have enough fuel for the intended flight plan so I don't see how it could have been an attack. I'd agree with others comments about mixed groups, you need to know what you're doing to be certain of it working.

 

Anyway, if this is normal behavior, please explain what's going on (so I can avoid getting myself into trouble in the future)... or let me know if it's not normal, and I'll try to capture an example situation for examination.

One option is to launch with the tanker and soon after they are formed up and cruising, do a forced refuel (alt R). Maybe you are only 100mile out but you've topped up the fuel used for launching (and the first launched loitering while waiting for the last). The tanker probably has time to get home and refuel to meet the survivors on the way home for a further top up if needed. Especially if you have a small amount of tanker fuel per 'plane this is more helpful than letting the normal flight take place.

Another thing to watch here is if you are landing a very big group very low on fuel some of them might run dry while circling for their turn in landing. In the past I think this caused problems with ghost groups.

In fairness to the GE, a flight comprising 24 hornets and one KA-6 is a bit out of the norm I'd suggest.

Don Thomas

[donaldseadog]

Out of interest I did three quick refuelling tests:

1/ 24 hornets and one KA-6 Intruder,

2/ 12 hornets and one intruder

3/ 12 hornets and two intruder.

 

the refuel cycle times (from 'xx00 starting to refuel xx01' to 'refuel complete, split group') were respectively:

72 mins, 37 mins, 18 mins.

so nearly an hour and a quarter for the situation of refuelling 24 hornets from one intruder.

In Joes cited situation the hornets were probably down to about 25% fuel at the start of the refuel (I seem to remember that is the trigger for auto refuel), so I guess with a surface attack loadout about 250 nm and I think each hornet would only get about 150 nm range extension from the refuel, so about 400 nm, with the low cruise speed of the intruder (350 kts?) you run dry before the cycle finishes.

In my test my hornets had intercept load outs so just got to the end of the 72 min IFR with some fuel remaining.

So I think that is what happened.

Don Thomas

[CV32]

In fairness to the GE, a flight comprising 24 hornets and one KA-6 is a bit out of the norm I'd suggest.

 

Considering one KA-6D has a maximum of 66.7 nm worth of fuel to give to each of 24 Hornets.

[Joe K]

For example, yesterday, I lost 24 F/A-18s after launching them, along with a KA-6 tanker, at a carrier group that was nearly at the limit of their un-refueled range ...

 

Two observations:

 

1. Your aircraft groups are probably too large and unwieldy to be useful.

2. A single KA-6D has very little fuel to offer to a group of 24x recipients.

1. Perhaps. Unfortunately, it's also rather unwieldy to manage "coordinated" attacks by 68 A-6Es, 60 F/A-18s coming from two bases, along with a sub and a SAG, if I use "normal"-sized groups. Also, I was hoping to "swamp" the target carrier group with Harpoons, seeing it would easily dispatch those missiles when launched from smaller groups. As it was, it took three attacks by this entire huge "package" before any Harpoons even reached the hit animation stage. I guess I tire easily of launching and managing them in smaller groups.

 

2. True. But, as I said, I added the tanker thinking it was "insurance" - in case a lot of the fuel range was used up by launching the large group. Actually, it would have allowed me to launch the group without the tanker, because the target was within range, albeit only minimally. So, it appears that I shot myself in the foot by including the tanker.

 

But, we digress... The real points of the example were the questions of why tankers sometimes don't try to separate on their own after refueling is done, and why including the tanker actually made the fuel situation worse.

[Joe K]

I'm not sure why the tanker would have stayed with the strikers, that sounds like a game glitch, for sure. However, given that it did, it's not surprising that you lost the F-18s. F-18s cruise at 490 kts, where as A-6s cruise at about 415 kts, IIRC. A mixed formation will always fly at the speed of the slowest unit in the formation. Unfortunately, aircraft burn fuel at the same rate for a given throttle setting, regardless of their speed. That is, the F-18s will use the same amount of fuel per hour whether they are flying at 490 kts or 415 kts, because both are within the 'cruise' throttle setting. So for the sake of discussion, if the carrier was 470 nm distant when the F-18s turned for home, and the F-18s had one hour of fuel left, the range circle, calculating on the basis of their normal speed of 490 kts, would say you had enough fuel to get home, because 1 hr * 490 kts = 490 nm. However, if the F-18s were forced by the presence of the tanker to only fly at 415 kts, they still only have one hour of fuel left, which means they run out after 415 nm, a full 55 nm short of the carrier. That's what happened to you. I hope I've stated this clearly?

 

I wondered myself whether the relative speed was at issue, although I surmized that F/A-18s flying at 415 knots would consume less fuel than at 490 knots (in RL, anyway).

 

As far as the game situation, I wonder whether it would be possible to avoid this by "micro-managing" the group's speed to 490 knots? (Of course, the whole point would have been moot if the tanker had split off when it was done re-fueling... and it seems unlikely that it would have taken all that time to refuel even 24 Hornets... so that part is a puzzle). I didn't dare split the tanker manually after the attack because I wasn't sure whether it was actually finished with the re-fueling. (Is there some way to tell?)

[CV32]

But, we digress... The real points of the example were the questions of why tankers sometimes don't try to separate on their own after refueling is done, and why including the tanker actually made the fuel situation worse.

 

Not really a digression, because it was starting off from that foundation that led to your disaster. Heck, it takes about 12.5 minutes for that kind of a group (25x aircraft) to even launch and form up.

 

One item I forgot to mention earlier was your admission that you weren't really paying attention.

 

Well, in HC, as it has been from time immemorial (to borrow a phrase), tanking requires your attention as it is a prime example of where the player is expected to exercise micro management. It has always been that way. Large and unwieldy groups only aggravate the issue.

 

As far as the game situation, I wonder whether it would be possible to avoid this by "micro-managing" the group's speed to 490 knots?

 

No, because then you're pushing the KA-6D at military speed.

[VictorInThePacific]

Out of interest I did three quick refuelling tests:

1/ 24 hornets and one KA-6 Intruder,

2/ 12 hornets and one intruder

3/ 12 hornets and two intruder.

 

the refuel cycle times (from 'xx00 starting to refuel xx01' to 'refuel complete, split group') were respectively:

72 mins, 37 mins, 18 mins.

 

Very nice. So we can say with complete generality hat one tanker deals with one plane at a time, and it takes 3 min for it to do so. Corollary: the last possible time to refuel a plane is about 3 min before it falls out of the sky.

[VictorInThePacific]

I'm not sure why the tanker would have stayed with the strikers, that sounds like a game glitch, for sure. However, given that it did, it's not surprising that you lost the F-18s. F-18s cruise at 490 kts, where as A-6s cruise at about 415 kts, IIRC. A mixed formation will always fly at the speed of the slowest unit in the formation. Unfortunately, aircraft burn fuel at the same rate for a given throttle setting, regardless of their speed. That is, the F-18s will use the same amount of fuel per hour whether they are flying at 490 kts or 415 kts, because both are within the 'cruise' throttle setting. So for the sake of discussion, if the carrier was 470 nm distant when the F-18s turned for home, and the F-18s had one hour of fuel left, the range circle, calculating on the basis of their normal speed of 490 kts, would say you had enough fuel to get home, because 1 hr * 490 kts = 490 nm. However, if the F-18s were forced by the presence of the tanker to only fly at 415 kts, they still only have one hour of fuel left, which means they run out after 415 nm, a full 55 nm short of the carrier. That's what happened to you. I hope I've stated this clearly?

 

I wondered myself whether the relative speed was at issue, although I surmized that F/A-18s flying at 415 knots would consume less fuel than at 490 knots (in RL, anyway).

 

As far as the game situation, I wonder whether it would be possible to avoid this by "micro-managing" the group's speed to 490 knots? (Of course, the whole point would have been moot if the tanker had split off when it was done re-fueling... and it seems unlikely that it would have taken all that time to refuel even 24 Hornets... so that part is a puzzle). I didn't dare split the tanker manually after the attack because I wasn't sure whether it was actually finished with the re-fueling. (Is there some way to tell?)

 

Warhorse expressed the process so well that there is no point is trying to re-express it. If anybody doesn't understand it, I would say, read his description again.

 

The reason a plane cruises at a particular speed is determined by physics; you can't change that. You can throttle back all you like until stall speed, but you always lose efficiency. (http://en.wikipedia.org/wiki/Cruise_(flight))

 

If you crank the speed of this mixed group up beyond cruise for the slower plane, then it must be flying at military. Maybe it has the range to do so, flying separately, but Harpoon doesn't allow you to have different throttle settings in one group.

 

As for how long it takes to refuel a bunch of planes, ask how many refueling probes a tanker has. Then Donald has showed that it takes 3 min per plane. Nothing unreasonable or unexpected in any of this. 20 planes per hour per tanker. Take it or leave it. When tanking is completed, the tanker is supposed to split off, and there will be other tells.

 

Thinking about all this, may I suggest that the reason the tanker didn't split off was that it was still working on that huge LONG task that it had been given and wasn't finished yet?

[donaldseadog]

.................... I didn't dare split the tanker manually after the attack because I wasn't sure whether it was actually finished with the re-fueling. (Is there some way to tell?)

If you don't mind cheating then, for a group with only one receiving unit (of any number of planes) you can split off the tanker(s) manually (F8) as soon as you see the bingo number jump or the range ring expand. This is cheating as Harpoon, unlike most games, is a realistic simulation and in reality refuelling takes time.

The way to tell (properly simulated finish to IFR) is that the 'split' request occurs. To my knowledge the only game glitch here is that the landing options sometimes omit the correct base/carrier in which case 'cancel' the request and your tankers should head back to their correct home plate.

I think if you sit back and look at all the facts that the various people have presented to you in this string you must agree that what happened was correct game function, the error was from your inexperience. From my own memory inexperience is almost always the cause of my grief, but it happens less now than it used to (still happens though, because there is much to learn, and that is where I get my Harpoon fun)

Don

[Joe K]

But, we digress... The real points of the example were the questions of why tankers sometimes don't try to separate on their own after refueling is done, and why including the tanker actually made the fuel situation worse.

 

Not really a digression, because it was starting off from that foundation that led to your disaster. Heck, it takes about 12.5 minutes for that kind of a group (25x aircraft) to even launch and form up.

 

One item I forgot to mention earlier was your admission that you weren't really paying attention.

 

Well, in HC, as it has been from time immemorial (to borrow a phrase), tanking requires your attention as it is a prime example of where the player is expected to exercise micro management. It has always been that way. Large and unwieldy groups only aggravate the issue.

 

I say it was a digression because the point here was that the usual split-off notification did not occur (and that's what I would normally key off of). I was not aware that it was necessary to pay attention to anything while awaiting the completion of IFR... but, if I do need to, then what do I need to be paying attention to during that time? (I mean, I don't know what information is provided that I could monitor, and I don't know what intervention I could make in any case, so...???)

 

I readily concur that my specific 24-plane example was extreme, and I used it ony because it was the most recent case and so the details were fresh in my memory. It certainly wasn't the only example, and in hind-sight, probably not the best choice because it lead to a critique of my technique rather than discussion of the non-split-off issue. But, despite any issue with the merit of the composition of my group, I'm not following how that led to the non-split. Are you saying that a single KA-6 can not service up to 24 F/A-18s over a distance of about 2100 nm? I can understand the issue of the KA-6 slowing the group down and thus eventually running it out of fuel, but I don't see why it never completed the re-fueling, and split off (and thus would have allowed those Hornets to resume their normal cruise speed - which may or may not have allowed them to reach base, but at least would have gotten further). But I digress yet again... the crux is why the split-off didn't happen.

 

I see this happen every so often where the tanker(s) does not ever split off (and it has happened with small groups, albeit without the loss of a/c as in my example). As I recall, it has usually shown up in connection with a ferrying operation, or with a group that is returning to base after a mission and the tanker was joined to the group sometime after the group had stated its return to base. I had always sort of dismissed this as possibly "normal" behavior, and my question was basically that: Are there circumstances where it is "normal" for (a) tanker(s) to stay with a group after finishing the IFR? If so, what determines that?

 

As an aside, I certainly realize that refueling operations may involve micro-management - at least as far as getting tanking groups together with thirsty groups in a timely manner, and coaxing them to start the IFR - but I didn't realize there was much to be done once they had finally started IFR. But if further micro-management is required, then may I suggest that something ought to be done to reduce that level of involvement, because otherwise, it would effectively mean that one cannot carry on other game operations concurrently with re-fueling activity - which seems to me to be unreasonably restricting of game play.