AAR, does the basket push against the jet?

Doing AAR and noticing real life footage where the jet hooks up and the basket acts as a brake once connected. Does this happen in DCS? Is there at least *some* resistance to slow the jet down once it connects?

Not currently. Wags said awhile back that they are going to rework the basket logic / physics. Cant wait for that.

The basket does not act as a brake IRL, it might just look this way from videos etc.

Inside the refuelling pod is a system to retract the hose as the receiver makes contact with it to stop the hose whiplashing back down towards the aircraft.

It reels the hose in and allows it to roll out as required based on what position the receiver is in.

The reworked basket physics that Wags mentioned was in relation to the receiver bow wave pushing the basket up and to the right just before contact.

;3794734']The basket does not act as a brake IRL' date=' it might just look this way from videos etc.[/quote']

 

I disagree. It does not make sense to think that the basket would not push up against the jet IRL and I'll bet that pilots use this resistance to brace the probe up against the basket while taking fuel. Those baskets are travelling anywhere between 200 and 300 knots so they will generate a significant amount of drag. I'll post this question to some real F-18 pilots and see what they say.

I'll post this question to some real F-18 pilots and see what they say.

You're still going to be wrong.

The drogue is simply flying along in the slipstream and has no forces to stop or slow the receiver aircraft. The hose is just that, a hose. If you have too much closer speed, you'll cause it to whip and may cause the drogue to snap off or become damaged. The drogue itself isnt reinforced against collisions or hard contacts.

The other type of drogue, the Boom Drogue Adapter (BDA) is tougher, but again does not act as a brake.

You're still going to be wrong.

 

The drogue is simply flying along in the slipstream and has no forces to stop or slow the receiver aircraft. The hose is just that, a hose. If you have too much closer speed, you'll cause it to whip and may cause the drogue to snap off or become damaged. The drogue itself isnt reinforced against collisions or hard contacts.

 

The other type of drogue, the Boom Drogue Adapter (BDA) is tougher, but again does not act as a brake.

And you know this how????

actually the basket does cause some minor push back, the resistance in the jetstream plus the actual spool effects means that you have a minor amount of push, it's not like hitting a wall or anything like that but it is there in the real world not to mention some other effects that aren't modelled currently in DCS like the fact the drogue has a minor amount of 'leading' as well no where near as much as the boom but it's there.. it's still attached to the tanker and while it's flexable it becomes a lot more ridgid when it's pumping fuel under pressure.

Wags and others in the ED team have already mentioned that there aware of the limits in the current system and we'll see it updated 'eventually'. Hopefully that means things like nose bubble, slip stream effects (which given we are getting some of those finally for all ac is nice), couple physics, and maybe even some physics for the drogue hitting our plane and moving around rather then going through it? What would also be nice is if the tanker talked to the pilot like he would in real life and warned about up coming turns ;)

Thanks... This will make AAR much easier so storm, maybe you should uninstall when they implement the change since it will make AAR easier.

:megalol::megalol::megalol::megalol:

The physics insists that there is a push if you move the basket in from its neutral position, and a pull if you move it out. I suspect that it is going to be only a few pounds, but it must exist, otherwise there would be nothing stopping it moving back and forth of its own volition.

When trailing there is drag trying to extend it, balanced by a mechanical pull from the hose mechanism itself, trying to retract it.

And you know this how????

Because I have 4000+ hours on the KC-135, smart guy.

Thanks... This will make AAR much easier so storm, maybe you should uninstall when they implement the change since it will make AAR easier.

 

 

:megalol::megalol::megalol::megalol:

And maybe Ace Combat might be more your speed. Low...

Personally apart from the drogue not being trailed before you got to the pre contact position I think the current AAR is not too bad. The basket is artificially big at times and you don't see the bow wave effect as someone mentioned but it's not bad. Unless the drogue malfunctions there is no appreciable force as you put the probe in the basket. If the drogue is not working correctly you will get a massive whiplash on the hose which can come back and rip your probe off. All you can do is drop back immediately and hope you are out before the wave returns. I only saw it happen once to my wingman.

So to reiterate from my experience the current AAR is about as difficult as it is in real life if you can fly close formation your can AAR. And the slightly bigger basket makes up for the lack of feedback

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I disagree.

Cool, you’re still wrong tho

Interesting because what I see in videos is the pilot mating with the basket and then using the drag of the basket to brace the jet and help the pilot hold it in position while he refuels. This makes more sense given the fact that at 200-300 knots the bow wave most likely won’t extend past the engines (KC-135). Obviously this is a guess but based on what I’ve seen in wind tunnels during Mach 1 speed tests, the bow wave will extend pretty far out so I’m guessing at much lower speeds it is relatively smaller. Also there are a lot of factors influencing the drag the basket creates. Bow wave, Wing vortices, low and high pressures exerted on or around the drogue as a result of jet wash.

One thing is certain though. The way it’s modeled in DCS is nowhere near as accurate enough. It would be nice to make contact and then feel a slight push back to simulate the drag on the basket.

;3795086']Cool' date=' you’re still wrong tho ????[/quote']

 

Doubt it sparky.....

Because I have 4000+ hours on the KC-135, smart guy

So you’re not a real pilot then. Keep trying

The amount of extra drag exerted on the aircraft by the drogue is negligible. Sure it does have some effect because once its connected its essentially being pushed along through the air by the tanking aircraft. But because of the way you are constantly moving the throttle when flying in formation its not something you'd notice... you're just concentrating on staying in position. You can't brace the aircraft agains't it because its not "pushing back" so to speak, its just like flying with a bit of air-brake out, you're simply operating at a slightly higher power than you would be without it.

The amount of extra drag exerted on the aircraft by the drogue is negligible. Sure it does have some effect because once its connected its essentially being pushed along through the air by the tanking aircraft. But because of the way you are constantly moving the throttle when flying in formation its not something you'd notice... you're just concentrating on staying in position. You can't brace the aircraft agains't it because its not "pushing back" so to speak, its just like flying with a bit of air-brake out.

I think you're right. The force pushing back against the jet *is* small and negligible but I'm sure pilots use this as a tiny tiny brace. If it wasn't there at all I'd assume there would be more throttle inputs just to keep the jet on speed.

I think of it this way. You can lean a hammer up against a book if the hammer is not tilted as much. Seems to make sense to me.

I disagree. It does not make sense to think that the basket would not push up against the jet IRL and I'll bet that pilots use this resistance to brace the probe up against the basket while taking fuel. Those baskets are travelling anywhere between 200 and 300 knots so they will generate a significant amount of drag. I'll post this question to some real F-18 pilots and see what they say.

No.... just..... no, and you don't need a physics degree to understand how this works. The basket is not completely free floating. The hose mechanisms feed it in or out freely, so the net ''effect'' is close to zero or it wouldn't work. If the basket breaks off, then yes, it's a draggy protrusion on the plane.

Secondly, the pilots aren't using drag to 'hold' the basket on there. It has a glorified quick connect not unlike what is used in your average automotive shop. The reason the receiving aircraft ''lunges'' into the basket initially is so it hits with enough force to engage the mechanism. Any abrupt movements at that point without the tanker actively disconnecting will cause either the probe or basket to break off. The pilots aren't ''holding'' anything. Once *locked* on, that basket ain't goin' nowhere until somebody *un*locks it.

Once connected it is formation flying, no more or less. Which people do constantly without needing weird basket physics to aide them.

No.... just..... no, and you don't need a physics degree to understand how this works. The basket is not completely free floating. The hose mechanisms feed it in or out freely, so the net ''effect'' is close to zero or it wouldn't work. If the basket breaks off, then yes, it's a draggy protrusion on the plane.

 

Secondly, the pilots aren't using drag to 'hold' the basket on there. It has a glorified quick connect not unlike what is used in your average automotive shop. The reason the receiving aircraft ''lunges'' into the basket initially is so it hits with enough force to engage the mechanism. Any abrupt movements at that point without the tanker actively disconnecting will cause either the probe or basket to break off. The pilots aren't ''holding'' anything. Once *locked* on, that basket ain't goin' nowhere until somebody *un*locks it.

 

Once connected it is formation flying, no more or less. Which people do constantly without needing weird basket physics to aide them.

I'm not saying the pilots depend on the drag to hold the jet in place I'm saying they use the little resistance there is, even if it's a teeny tiny minuscule amount of resistance, to *help* them hold the jet in place, that's all.

If it's possible for something that's for all intents and purposes nonexistent, then sure.

The biggest 'flaw' in the current modeling is you can't wrap the hose are the nose and rip it off, and you clip through it instead of getting the canopy bashed in =) Lastly, it could stand to be a little more ''floaty''

I'm not saying the pilots depend on the drag to hold the jet in place I'm saying they use the little resistance there is, even if it's a teeny tiny minuscule amount of resistance, to *help* them hold the jet in place, that's all.

How would it help them though? its a constant force just like ALL the other drag of the aircraft that the engines are overcoming. It doesn't push back more the further forward you move, it stays the same. Therefore its just the same as flying without it, except you're using a fraction more thrust. You still need to move the throttle in the exact same way you would to hold position vs the tanker if the drogue/hose wasn't there.

If it's possible for something that's for all intents and purposes nonexistent, then sure.

 

The biggest 'flaw' in the current modeling is you can't wrap the hose are the nose and rip it off, and you clip through it instead of getting the canopy bashed in =) Lastly, it could stand to be a little more ''floaty''

Lol, I can live with that as long as I get a little push back when I hit it at 0.5kph so I don't fly right through it and get the panicky "break off" warning on the radio.

How would it help them though? its a constant force just like ALL the other drag of the aircraft that the engines are overcoming. It doesn't push back more the further forward you move, it stays the same. Therefore its just the same as flying without it, except you're using a fraction more thrust. You still need to move the throttle in the exact same way you would to hold position vs the tanker if the drogue/hose wasn't there.

The force pushing back against the jet *is* small and negligible but I'm sure pilots use this as a tiny tiny brace. If it wasn't there at all I'd assume there would be more throttle inputs just to keep the jet on speed.

I think of it this way. You can lean a hammer up against a book if the hammer is not tilted as much. Seems to make sense to me.

The force pushing back against the jet *is* small and negligible but I'm sure pilots use this as a tiny tiny brace. If it wasn't there at all I'd assume there would be more throttle inputs just to keep the jet on speed.

 

I think of it this way. You can lean a hammer up against a book if the hammer is not tilted as much. Seems to make sense to me.

Thats not how drag vs thrust works... Your idea works if the drogue would increase its drag the further forward you pushed the drogue, then eventually you would reach a point of balance between the drogue increasing its drag as the aircraft moves forward and the thrust being applied by the engines and the aircraft would want to stay in a specific spot... that is until the weight of the extra fuel made it drop back.

However... The drag of the drogue doesn't change depending on how forward of aft it is in the refuelling box. So it doesn't work like you suggest.

If I may, the hose and basket absolutely cause a drag effect on the aircraft being refueled. The extent to which this is felt and interpreted by the pilot flying the receiving aircraft isn't something I can accurately comment upon, but the effects are certainly there. For this explanation, my convention is: Force in the direction of the aircraft's travel = positive (e.g. thrust); force opposing the forward movement of the aircraft = negative (e.g. aerodynamic drag).

We've already established that the basket is connected to the aircraft. Any structure that is attached to an aircraft is going to create some amount of parasite drag, and the basket is no exception. The drag being produced is actually fairly significant, given that the basket is designed to produce drag in order to keep the hose taut and allow the receiving aircraft to hook up.

That being said, there is a spooling unit in the tanker that reels out or retracts the hose based on the forces being introduced to the hose system. However, this unit has necessarily high damping constants to make up for the positive feedback being produced by the hose, the receiver, and the environment. Notably, the hose is subject to rather complex catenary force, which is only approximated by the hose controller since catenary is notoriously difficult to calculate on the fly. This is in addition to the previously mentioned and ever-changing rigidity of the hose depending on fuel flow rate and any resistance introduced by movement of the receiving aircraft. Because these forces are only approximated, there is a dynamic push-pull happening between the tanker, hose, and receiver. The spooling unit does relieve some of the negative force being produced by the drag of the basket, but it is incredibly optimistic at best to pretend that retracting and extending the hose artificially would entirely negate the effects of the basket on the receiving aircraft.

There are also the "soft" effects of the basket, especially the interruption of smooth airflow over the receiving aircraft. This is one of the more negligible aerodynamic effects of refueling, but it certainly contributes to the system.

I'd be curious to hear some real Hornet pilots weigh in, or really anyone who has flown on the receiving end of a drogue in real life.

My references are my own experience in avionics control systems and engineering flight test, as well as the papers:

"Modeling and Simulation for the Automation of Aerial Refueling of Military Transport Aircraft with the Probe-and-Drogue System" by Nicolas Fezans and Thomas Jann

and

"An Introduction to the Navy's Physics Based Model of the Hose and Drogue Refueling System - Design and Validation" by Kenneth E. Boothe, Robert Vess, Eric Koehler, Elizabeth Knoblauch, and Steve McLaughlin