A10C Refuel "Auto-pilot"

[MasterZelgadis]

I think (if this effect ever happens..) fuel weight can't be the reason. With no input change the increased weight should slow the plane down, causing the nose to drop rather than pull up.

If any autopilot kicks in there should be a clearly hearable "pling" sound.

[SharpeXB]

The autopilot is disabled when you open the refueling door

 

This can happen, you can get stuck on the end of the probe, it looks connected from your pov but it's not

Edited August 30, 2016 by SharpeXB

[Xavven]

Hmmm, I suspect this could have something to do with a trim problem mentioned somewhere on these forums.

 

Can you reproduce the issue again, but do it with the "show controls indicator" on? By default you press RCTL+Enter to turn it on. You'll see an indicator in the lower left of the screen that shows you what your control inputs + trim are doing together. What I'm looking for is a sudden jump on the stick (diamond) when you connect, which would indicate that your trim is getting reset (which is a bug).

 

Someone on these forums noticed this happening upon landing under some circumstances, causing a balloon upon landing flare that is not at all a result of ground effect, bad flying, etc., but rather the game suddenly adding in a ton of nose-up trim on the flight controls.

[SharpeXB]

iPS: In my case, the tanker's reply to "Ready pre-contact" is "Cleared contact", not "Close to contact". Could you double-check that you have the latest version of DCS World installed (1.5.4.55952 as of the writing of this post)?

Yes, that's it "Cleared to contact" I'm using the latest version of 1.5.

If you hear "Return pre contact" I assume that means "return" to your per contact position and try again. Sometimes after that message you need to request contact again if you have got too far out of position. So that might be the reason the operator is not responding. Try going back and start the approach again, if you approach correctly you'll see the boom raise up at start following you. But don't follow the boom, just proceed into station on the tanker, hold steady and it will connect.

The correct position looks like this

Edited August 30, 2016 by SharpeXB

[Ilyushka00]

Someone on these forums noticed this happening upon landing under some circumstances, causing a balloon upon landing flare that is not at all a result of ground effect, bad flying, etc., but rather the game suddenly adding in a ton of nose-up trim on the flight controls.

 

Yup I get that when landing sometimes

[SharpeXB]

Perhaps check for having a button double mapped to "Take off Trim" or one of the other emergency trim overrides.

[Thisdale]

Yup I get that when landing sometimes

 

Come to think of it, that's happened to me a few times during the Hammer campaign.

 

And i did another refueling session on Aerobatics 2.0 (nevada). Had a bunch of "clear contact" then sudden pitchup/bounce. Very close to the 130's tail every times.

[Thisdale]

Alright. Well i wanted to make a video capture from in-game footage, but the replay breaks completely and i wasn't able to get the event properly (tanker and A10 are miles apart...go figure).

 

Instead, i captured one of the hickups i refer in the OP with TacView. We don't see the boom's position. But essentially i make contact with the boom properly. As soon as that happens, the RadioDude says "Contact" and i get catapulted upwards into the Tanker's tail.

 

Fuel door is open

Ready light is set (nose steering button press).

 

I experience this type of "event" about once every 5 refuel attempts i do.

What you see in the video is NOT a result of pilot input.

 

${1}

(youtube is not happy:

)

[Xavven]

Alright. Well i wanted to make a video capture from in-game footage, but the replay breaks completely and i wasn't able to get the event properly (tanker and A10 are miles apart...go figure).

 

Instead, i captured one of the hickups i refer in the OP with TacView. We don't see the boom's position. But essentially i make contact with the boom properly. As soon as that happens, the RadioDude says "Contact" and i get catapulted upwards into the Tanker's tail.

 

Fuel door is open

Ready light is set (nose steering button press).

 

I experience this type of "event" about once every 5 refuel attempts i do.

What you see in the video is NOT a result of pilot input.

 

(youtube is not happy:

)

 

That really does look like the trim bug...

 

Can you reproduce the issue again, but do it with the "show controls indicator" on? By default you press RCTL+Enter to turn it on. You'll see an indicator in the lower left of the screen that shows you what your control inputs + trim are doing together. What I'm looking for is a sudden jump on the stick (diamond) when you connect, which would indicate that your trim is getting reset (which is a bug).

[Yurgon]

SharpeXB, I can't tell whether you're honestly trying to help, or whether your deliberately trying to be condescending, or whether you're just too lazy to read. Anyway, please stop trying to help me, I've invested far too much time into this side-topic already. My point is: The boom operator won't connect on his own, period. If you have proof to the contrary, by all means present it (it would also be cool to get input from other players).

 

[...] my experience was that you don't have to fly into the boom, just hold the correct position a few seconds and the boom operator plugs it in. [...]

 

Yup, I think that's the way it used to be, but right now I can't for the life of me get the boom operator to do that (as I tried to show in the track posted a page or so ago, hint, hint).

 

Instead, i captured one of the hickups i refer in the OP with TacView. We don't see the boom's position. But essentially i make contact with the boom properly. As soon as that happens, the RadioDude says "Contact" and i get catapulted upwards into the Tanker's tail.

 

This looks a lot like one of the problems I saw in your track. But without seeing the boom, it's impossible to tell from the replay whether it happens before or after contact.

 

Like I said, in your track the problems always seemed to appear before contact, not after, so I still don't know what happens, and I still see zero evidence that this is in any way connected to trim or the autopilot. Not saying it isn't, just that neither the track nor the Tacview-recording provide any proof at all as far as I can tell. Weird problem, in any case.

 

@all: Why do some of you guys ask questions that are easily answered by looking at Thisdale's track? It's rare enough that someone does upload a track. If you don't have time to watch it, why do you have time to ask about this or that switch position? :noexpression:

 

That really does look like the trim bug...

 

Interesting. Do you remember common problem solving solutions for that bug? Would DCS repair help, or reinstalling? Or renaming the Saved Games\DCS folder? In case there's something wrong with Thisdale's installation, these would be my first attempts at trouble shooting.

[SharpeXB]

SharpeXB, I can't tell whether you're honestly trying to help, or whether your deliberately trying to be condescending, or whether you're just too lazy to read. Anyway, please stop trying to help me, I've invested far too much time into this side-topic already. My point is: The boom operator won't connect on his own, period. If you have proof to the contrary, by all means present it (it would also be cool to get input from other players).

 

Watch this tutorial, you'll see the boom movement when he gets into the right position and then the connection.

 

[SharpeXB]

Good idea! Forgot all about dropbox.

 

Here's the track.

During flight, i've tried various ways to approach to the boom. Sometimes it works fine. Other times the stick becomes solid and the plane gets catapulted.

I've tried with the refueltrap open and closed as well (seems to happen in both instances).

 

https://www.dropbox.com/s/jzql9hgkid99bz2/a10crefueljerking.trk?dl=0

 

Ok I watched your track. You are closing with the probe too fast, it's raising up when your in position but your coming at it too fast, just fly off the tanker and don't look at the boom. The bumping behavior is your nose hitting the probe. It's not a trim problem. You've got a really steady hand on the approach, just keep that going in. Also if you get disconnected remember to press the nosewheel steering button to reset the fueling door. That's why the subsequent attempts won't connect, your ready light is off. Keep the steady hand you've got in the beginning and you'll nail it :)

[Xavven]

 

@all: Why do some of you guys ask questions that are easily answered by looking at Thisdale's track? It's rare enough that someone does upload a track. If you don't have time to watch it, why do you have time to ask about this or that switch position? :noexpression:

 

:doh: Dammit, you're right, Yurgon. For some reason I either skipped right over his post or mistook the track link for a signature. A track is worth a thousand paragraphs.

 

Alright, I hate to break it to you, but this is not the trim-reset bug. It's actually your A-10 bumping into the tanker's refueling boom. On your first two or three approaches, you are too high relative to the tanker. It might not look it from the point of view of the cockpit, but the bottom of your nose is hitting the top of the end of the boom, pushing your plane upward. Here's a screenshot of the exact moment you collide with the boom, from an external view. No offense intended, of course!

 

Edited August 31, 2016 by Xavven
EDIT: Yurgon is probably thinking, "yeah, Xavven, I posted that like 20 posts ago!" LOL

[Yurgon]

Watch this tutorial, you'll see the boom movement when he gets into the right position and then the connection.

 

These boom operators look a lot more cooperative (most of them anyways):

 

https://www.youtube.com/watch?v=7OfgdK1BKiM

 

As far as I can tell, the tutorial you posted comes relatively close to showing the uncooperativeness (is that a word? ;)) of the DCS AI boom operator. That particular video from 2012 showed a magic connect after the player aircraft was established a few inches off the boom.

 

My experience from the past couple of days has been that even such a close flight doesn't get me connected unless I have a positive closure rate on the tanker.

 

Anyway, my impression is that the tolerance for connect is really, really tiny right now, and that the AI boom operator is less helpful than it used to be. If by "just fly off the tanker, don't fly into the boom" you mean to suggest that the A-10 should fly within a tolerance of inches, or even fractions of inches, I might be inclined to agree with you. It just doesn't correspond with what I believe it should be.

[MasterZelgadis]

Watch this tutorial, you'll see the boom movement when he gets into the right position and then the connection.

 

 

That tutorial is 4 years old. About the same time I flew my last AAR. Many things can have happened since then..

[Gliptal]

:doh: Dammit, you're right, Yurgon. For some reason I either skipped right over his post or mistook the track link for a signature. A track is worth a thousand paragraphs.

 

Alright, I hate to break it to you, but this is not the trim-reset bug. It's actually your A-10 bumping into the tanker's refueling boom. On your first two or three approaches, you are too high relative to the tanker. It might not look it from the point of view of the cockpit, but the bottom of your nose is hitting the top of the end of the boom, pushing your plane upward. Here's a screenshot of the exact moment you collide with the boom, from an external view. No offense intended, of course!

 

Nice catch. Turns out I nailed it in the first few posts after all. :D

 

What has changed lately is the boom now has a weight associated to it. It may be helping the aircraft to stay in position.

Tried a few refuelings yesterday and to me it looks like you simply need the plane to remain steady for just a few seconds in a very precise spot to get connected.

Once you are connected the margin until disconnect happens becomes way bigger.

I have the same feeling.

[SharpeXB]

Tried a few refuelings yesterday and to me it looks like you simply need the plane to remain steady for just a few seconds in a very precise spot to get connected.

Once you are connected the margin until disconnect happens becomes way bigger.

That's my experience as well.

I did a lot of AAR in the Maple Flag course. Although that tutorial is old, I don't see anything different.

 

Here's a track from the current Maple Flag training mission, made today with the current version of 1.5

I'm a bit out of practice so it's a better example that way, I manage to bump the boom a few times too and you can see the effect. Watch how when you hold position in the right spot the operator will connect you and how the boom is following you. Don't close with the boom too quickly, it will come to you.

AAR MF Day SharpeXB.zip

Edited August 31, 2016 by SharpeXB

[Thisdale]

Very interesting point.

I flew another tryout yesterday (and the game crashed, so no track :( )

 

But i did a bunch of mistakes on purpose, to try and figure out what the hell happens. A few things came up, which i will write up with bug reports in the appropriate place (and try to support with track captures).

 

Things i tried:

 

Try Connection with Door closed

Try Connection with Door Open

Bump Boom from right

Bump Boom from left

Bump Boom from under

Bump Boom from Above

On ClearContact;

Move plane Right (rudder & roll)

Move Plane Left (rudder & roll)

Disconnect from lose of power (pull back)

Push under the Tanker (disconnect from too far front)

Closed Refuel door while connected

A few other things i don't remember.

 

1. About OP; you are right Xavven. I noticed yesterday that one of the reason why i'm sent to the stratosphere is because the Hog's nose hits over the boom.

 

2. "1" is also a big bug/problem. Because with "regular laws of physics", there's no way in hell bumping into the boom at 2 knots faster than the Tanker sends you flying up. It'd push the boom out and the BoomOperator should call a "wave off" or "pull back" or whatever else he says. So there is a Physics problem here.

 

3. The Boom's initial position on Ready-Contact is fully extended, which shouldn't be the case. In all videos we see shared by Yurgon:

 

https://www.youtube.com/watch?v=7OfgdK1BKiM)

 

we see the Boom is pointing down, but the straw is fully retracted. Once the plane is in position, the straw comes out at the Operator's command and makes connection.

 

The proper procedure, based on observation of all those youtube videos anyways, is for the plane to get in ready-contact position. AFTER WHICH, the boom operator aims and extends the Straw. This is not what we have in-game (we have the opposite).

 

Additional note: This is also part of the reason why, after reviewing my approches, i always aim for the fins of the Boom, and not the tip of the straw. As you get close to the Boom, it usually moves forward and up to meet you. If i aim at the tip of the straw as it is now (full extended), you always come up short and at the very range-limit of the straw. By aiming at the Fins, you let yourself, and the BoomOperator, the entire straw in manoveurability for the refueling.

 

4. I've noticed yesterday that, when the boom touches your plane (regardless of where, with the single exception of a perfect contact), it exerts an immense amount of force (tons). It literraly pushes your plane out of the way. Which brings me back to "1". I've had moments where my Hog was 30degrees to the side (equivalent of full Immediate Rudder).

 

There is no way in hell the Bomb of a Tanker is designed this way. That thing should bend/fold, bounce or shatter rather than send a plane flying in all directions, with the incredible danger of crashing into the Tanker, or other wings nearby.

 

5. In all my testes, there is a constant: The Boom is RIGID. The Boom itself, and the straw that comes out (with the color gradient). Which is not the case in the real case. There is a great amount of flexibility built into the straw itself. This results in, as soon as you are near the boom/straw, it is as stiff as a pole and exerts too much force, which result in the planes bouncing in all directions.

 

6. I've also noticed that, once you are connected and take fuel, everything becomes stable (which is fine). The Boom and Straw move normally as long as you can fly your plane.

However, the Moment you are full of Fuel, the "tanker" reverts to its "Ready-Contact"state, and the Boom is immediately disconnected. Which explains why sometimes i'm sent flying in a "random" (which is now officially not random) direction. The moment you are disconnected, the Boom becomes Rigid again ("5") and you basically bounce off it again.

 

 

Overall, works, but there are a few issues with the system; mainly the physical force applied to the plane, from the boom.

 

On a side note; i've put in about 5 hours of practice in refueling in 1 week... and i've gotten pretty damn good at it ;)

 

 

Also, on another sidenote(unrelated), i found this: http://www.codeonemagazine.com/c130_article.html?item_id=56

 

 

 

Alright, I hate to break it to you, but this is not the trim-reset bug. It's actually your A-10 bumping into the tanker's refueling boom. On your first two or three approaches, you are too high relative to the tanker.

 

[Yurgon]

Here's a track from the current Maple Flag training mission, made today with the current version of 1.5

I'm a bit out of practice so it's a better example that way, I manage to bump the boom a few times too and you can see the effect. Watch how when you hold position in the right spot the operator will connect you and how the boom is following you. Don't close with the boom too quickly, it will come to you.

 

Thanks for the track! And good flying. :thumbup:

 

The funny thing is, I think this track proves my point more than yours. :D

 

I counted 5 connects with a positive closure rate towards the tanker, and 3 connects where you flew within a few inches of the boom, settled there, until the boom magically connected one or two seconds later.

 

I think the operator should cover a larger gap than he currently does in DCS. I think he used to do that, but I'm not 100% sure about that.

 

In any case, I believe now that you're right that the boom actually connects from a stable position under very specific circumstances. However I also still believe these circumstances aren't realistic and make things harder for us than they should be. :smartass:

 

Very interesting point.

I flew another tryout yesterday (and the game crashed, so no track :( )

 

Probably too late now, but the game automatically saves the last flight's track, and I think it's written continually, so even if the game crashes, the track should contain everything until the crash.

 

In my case, the path is:

 

C:\Users\{My Windows User}\AppData\Local\Temp\DCS\LastMissionTrack.trk

 

Be aware that that path can be different; if you don't find such a file there, just search for "LastMissionTrack" in the forum or in your filesystem and there should be some good hits. :thumbup:

 

Glad you found the source of your problem! :)

 

I think while trying to figure things out, I also got a pretty solid refresher on AAR and how to get it to connect. ;)

[Thisdale]

 

 

Probably too late now, but the game automatically saves the last flight's track, and I think it's written continually, so even if the game crashes, the track should contain everything until the crash.

 

already checked. File's not there. DIdn't get a tacview file either.

Anyways, it's not like it's my last Refuel run ;)

 

 

On a side note, found this incredibly interesting article:

 

http://foxtrotalpha.jalopnik.com/confessions-of-a-usaf-kc-135-flying-gas-station-boom-op-1578048155

 

Daytime refueling with a stealth [F-117] was stressful enough. Just scraping a stealth with RAM (Radar Absorbent Material) coating outside of the receptacle area meant an ass chewing when you got back to base, not to mention the possible affect it could have on a jet's stealth capability. Now we were facing refueling the F-117s and "the others" at night, with no lights on, and no communications. Receiver aircraft simply flew to where they knew the tanker would be and got enough fuel to get back to home base so that they could reload and launch again. It was an all out free for all.

Edited August 31, 2016 by Thisdale

[SharpeXB]

Well this is a game after all. The physics and collision stuff is I'm sure one of the more difficult things to model. If you look at my earlier screenshot I mangled to get it stuck into my nose. So exactly how much colliding with a boom in real life would knock your plane around? No idea. But your not supposed to hit the boom ;-). It's better to lose contact by being too slow than being too fast and colliding with the tanker. That's bad.

A lot is in the throttle inputs. You're on and off like the gas pedal in your car keeping distance from the car ahead of you. But there's a lag. So by the time you see yourself closing with the tanker it's too late and vice versa.

 

Additional note: This is also part of the reason why, after reviewing my approches, i always aim for the fins of the Boom, and not the tip of the straw. As you get close to the Boom, it usually moves forward and up to meet you. If i aim at the tip of the straw as it is now (full extended), you always come up short and at the very range-limit of the straw. By aiming at the Fins, you let yourself, and the BoomOperator, the entire straw in manoveurability for the refueling.

 

It sounds like you're making good progress. But once again. Don't look at the boom. Pretend it's not even there. Just acquire a mental sight picture of what the tanker looks like when you're positioned correctly and hold that. If you disconnect, no big deal. Keep concentration and press the nw steering button and maintain station. But don't chase the boom or even look at it. What the boom does or doesn't do shouldn't factor in at all.

Edited August 31, 2016 by SharpeXB

[Yurgon]

On a side note, found this incredibly interesting article:

 

http://foxtrotalpha.jalopnik.com/confessions-of-a-usaf-kc-135-flying-gas-station-boom-op-1578048155

 

Great read, thanks for sharing! :thumbup:

[Thisdale]

Hey guys,

 

Did yet another session in air refuel with the Hog yesterday on Aerobatics 2.0.

 

Now knowing what's been said in these parts, the session went very well. Smooth approach, much easier time connecting and easy transfer of fuel.

 

I've noticed a few other things that bug me and i'd like everyone's opinion here:

 

1. I've noticed that when connected to the boom (more than when not anyways), the Hob tends to always want to go up. I've trimmed to the best of my abilities, but it seems 1 trim up is too much, and 1 trim down is too much, so the Hog always oscilates up and down slightly. It makes for a rather difficult "formation flight" with the tanker. The wierd part is, as soon as i'm no longer connected, that oscilation stops.

 

At first i though this oscillation was a "simulated" turbulence due to the Hog's position under the Tanker. But it only occurs when fuel is transfered.

 

2. On Disconnect, it is very, very hard to not hit the boom. I've identified two reasons for this;

 

First; the boom is rigid (as stated in a previous post of mine) and does not retract at all when disconnected. So you go from being attached, to not, with no room to play.

 

Second; There is no warning when the disconnection occurs. Now this can be due to multiple reasons. First, no radio communication between Tanker and Flight. But there are situations where this would happen (above enemy territory for example; radio silence). But there is also new warning in-cockpit about the fuel tanks being full (is this byplane design?). I'm thinking about when you pull to a gas station and put fuel in a car. That handle you press to push fuel will snap to the "off" position when it feels the pressure increase. That's your sign that the tank is fuel. But you manually extract the hose from your car. Finally, through regular procedure, shouldn't the pilot close his trap to terminate Refueling?

 

The issue i'm having now is, the second i get a "refueling complete", my plane invariably bounces off the boom. It goes from a "connected" state to a "two foreign objects" incredibly close and bouncing off one another. Now if i had a warning that stated that Disconnect would occur, i could slowly pull back on the throttle and let the Hog drift backward, and prevent contact/collision. But i have no warning. It just happen and i bounce around next to the Boom'straw.

 

Thoughts?

[SharpeXB]

Just guessing here because I don't know the real procedure. I'm sure somebody here does.

But how would the boom operator know your tanks are about to be full and tell you he's going to disconnect? I imagine it works just like the gas pump on your car, it detects when it's full and disconnects automatically.

As for hitting it afterwards if you're holding station correctly that shouldn't happen. Cut your throttle and nose down a bit and you're clear of the boom.

As for trim and pitch when you're connected. Yeah you're always correcting. That's realistic. Why would the plane fly itself? And it's going to take on weight which will change your trim in any case.

[Thisdale]

 

But how would the boom operator know your tanks are about to be full and tell you he's going to disconnect? I imagine it works just like the gas pump on your car, it detects when it's full and disconnects automatically.

 

At a gas station, the pump stops pushing gas when it changes a heavy change in pressure (raising). But it doesn't Disconnect. It stops feeding. You, the driver, remove the handle from the hole.

That is a pretty big distinction.

Also, the Tanker Operator has gauges that tells him about that. He needs to set the pressure and fuel quantity prior to the plane's connection (pre-contact). Stands to reason, he'd also have a procedure to disconnect once the refueling is complete.

 

My issue right now, is that the moment i'm done refueling, the Boom stops being receptive to my plane's movements (as it was while connected). It just sticks out, fully rigid. So if my plane moves a micrometer in any direction other than down, i hit the boom and bounce off uncontrolably.

 

There is zero time to initiate a pulloff. I don't know when i'm being disconnected. By the time the operator tells me "Refueling complete", the Boom is already rigid, i'm still flying close-formation against what was a maneuvering Boom, but now the boom (in 1 frame, 1/30 of a second later; a moment later) has become completely rigid and unresponsive.

 

This being a videogame, its the kind of binary reaction problem you get often. There is no reaction time "built in" the system. It's "On" or "Off"

 

If you look in this video (which is great 'cause the pilot's having trouble at first). At 2:38, he disconnects.

 

 

The sequence of events are:

1.Hog is full

2.Boom nozzle disconnects (you see the clasp releasing).

3.The Boom's Straw (and nozzle) starts to pull away immediately. <- This is very important.

4.The Hog slows down and pulls away.

 

In DCS right now, what i experience -every single time-, is the following:

 

Hog is full

1.Boom nozzle disconnects

2.There is uncontrolled contact between Hog and Nozzle (It's not trying to get away from me, it just stays there).

3.I get operator message "refueling complete"

4.I start to fight the controls to avoid the Boom and pull away (because it didn't move from its position and i'm essentially hitting it constantly because, 1 frame earlier, i was receiving fuel and was connected to it.

 

I've watch countless F16s get fuel as well, which is very tricky, because the boom needs to position itself to the side while the F16 gets in position because of its bubble canopy. Once the Viper's in position, the boom moves back to its centerline and plugs in. The exact opposite happens when the refueling is complete. The boom moves away. Not the Viper.