Notching & BVR Tactics, help for new fighter pilots (FC3)

[Couladin]

Well Siskin, consider this: what if you DON'T slow down after launch?

 

In the timeframe you describe, you lose nothing. But you keep your ability to use energy to defeat threats. You also keep your ability to stay high - that is, to maintain Potential Energy. As shown: you've lost nothing, but gained a lot of things, and also as shown - your speed does nothing to change the thread's closure if it exists; but having speed ensures you have greater resources to combat said threat, if it exists.

 

Another point to recall is that jet engines are not rockets. They use air, and thus going below certain speeds means your engines will be less effective. This is the same thing as how your engines are less effective at altitude: up high, less air, less WHOOOMPF from your F100s - and thus, if you find yourself in trouble... less ability to do something about it.

 

Point taken.

[GGTharos]

I don't have one of those handy, but it's simple enough:

 

Put the missile on the 2 or 10 o-clock (not on the beam because it will fall behind you, you want it to be on your beam when you're performing this maneuver - watch the missile if you can and adjust the starting position as needed).

 

When the missile is close enough, do a max-g pull (you can do this inverted as well, depends on what you want to achieve) and keep pointing the wing right at the missile (ie. roll).

 

This will work against missiles will less energy, or certain missiles that couldn't keep up with a max-g out-of-plane pull even if they're 'full of energy'.

 

 

Edit: Another advantage, which I am not sure if it applies to DCS (hopefully not yet rather than never) is that you shield one half of your plane even if the missile detonates near you. You can see the advantage in that if you have two engines.

 

Wish someone could post a quick vid and diagram of an "orthogonal roll".

 

I gather the orthogonal roll maneuver is really only useful if the missile is just about out of energy... but would love to hear more about how to execute it and in what situations.

Edited January 14, 2013 by GGTharos

[EtherealN]

when cranking should i be going down and up as well as side to side?

 

Crank is maintained, you don't wave side to side. Place target on radar gimbal limits, keep him there.

 

Going up and down can be useful in long-range BVR if he has fired upon you (or you believe he has fired upon you), to make his missile maneuver extra and thus bleed it of energy.

[arteedecco]

Another point to recall is that jet engines are not rockets. They use air, and thus going below certain speeds means your engines will be less effective. This is the same thing as how your engines are less effective at altitude: up high, less air, less WHOOOMPF from your F100s - and thus, if you find yourself in trouble... less ability to do something about it.

 

Ah well... so... it's all about mass of airflow being moved and engine RPM.

 

Higher (at the altitudes we are talking) is usually colder, but yes thinner... However... remember we read Indicated Airspeed which means... effectively same amount of molecules at any given altitude if Indicated Airspeed is held constant.

 

So... I don't agree with the statement that jet engines are less effective up high for a constant Indicated Airspeed. Also... faster means more airflow... means more thrust out of engine (so their output increases as you go faster). A lot of the thrust from a jet is actually in the compressor stages... of course using afterburner changes that.

 

IF, you have a reduced RPM... a jet engine will "lag" and take a bit to "spool up", but again with afterburner ... it helps to even things out.

 

Plus... a missile has less air to interact with up high... so it is in a somewhat similar predicament in terms of maneuvering (not thrust so much since they are (all || most)? solid rocket boosters).

 

Mind you, I'm not saying you have the same "WHOOOMPF" (acceleration) up high as you do down low... I get the overall sentiment of what you're saying.

 

For those inclined to read more, link to nasa paper on the topic. Entirely possible I have misinterpreted... feel free to disagree and correct me where I'm wrong! :)

 

Cheers! :)

[Couladin]

@arteedecco check PMs.

[arteedecco]

I don't have one of those handy, but it's simple enough:

 

Put the missile on the 2 or 10 o-clock (not on the beam because it will fall behind you, you want it to be on your beam when you're performing this maneuver - watch the missile if you can and adjust the starting position as needed).

 

When the missile is close enough, do a max-g pull (you can do this inverted as well, depends on what you want to achieve) and keep pointing the wing right at the missile (ie. roll).

 

This will work against missiles will less energy, or certain missiles that couldn't keep up with a max-g out-of-plane pull even if they're 'full of energy'.

 

Okay, interesting... so you are basically forcing the missile to recalculate constantly for a turn (change in heading) AND a high-G altitude change... so a dynamic change in two planes at once?

 

Is the idea to effectively roll... around the missile as it closes in? (obviously it never just stops so you never complete the roll around it, but it's like a wave curl, right?)

[GGTharos]

Actually you get more thrust at speed because of the airflow you mentioned, and less thrust if you're slow. Thus the saying, the faster you go, the faster you go faster.

 

Mind you, I'm not saying you have the same "WHOOOMPF" (acceleration) up high as you do down low... I get the overall sentiment of what you're saying.

[EtherealN]

Higher (at the altitudes we are talking) is usually colder, but yes thinner...

 

I neglected to mention this: colder air can be conducive to greater engine performance, since you can perform greater heating before striking tolerances for your engine components. However, these two do not necessarily compensate for each other linearly.

 

However... remember we read Indicated Airspeed which means... effectively same amount of molecules at any given altitude if Indicated Airspeed is held constant.

 

Inertia when maneuvering does, however, not care about indicated. You spend more to do less. (Otherwise, F-15's would be going to orbit without a problem. ;) )

 

So... I don't agree with the statement that jet engines are less effective up high for a constant Indicated Airspeed.

 

I'm not talking about ability to maintain status quo. I'm talking about ability to gain Kinetic Energy (speed) as you spend Potential Energy (fuel). Invite you to test maneuvers at a given IAS at several altitudes from angels 5 to angels 50. Same engine, same thrust, same IAS...

 

Also... faster means more airflow... means more thrust out of engine (so their output increases as you go faster). A lot of the thrust from a jet is actually in the compressor stages... of course using afterburner changes that.

 

Correct in principle, but not enough to compensate. They don't trade linearly. If they did, all jet aircraft would have the same ceilings. ;)

It's not the "true air speed" entering engines you're looking for. It's the mass of air. Jet engines are "breathers" - but they don't "breathe" speed, they breathe oxygen. Give them more oxygen and they'll give you more thrust. This is obviously, though, a balance against drag. But the point is that you cannot take two unknown altitudes and automatically say that the one with the faster TAS has your engines produce more thrust.

 

Mind you, I'm not saying you have the same "WHOOOMPF" (acceleration) up high as you do down low... I get the overall sentiment of what you're saying.

 

The "overall sentiment" is what applies to these aircraft and the operation thereof. ;)

Edited January 14, 2013 by EtherealN

[GGTharos]

Okay, interesting... so you are basically forcing the missile to recalculate constantly for a turn (change in heading) AND a high-G altitude change... so a dynamic change in two planes at once?

 

Think out-of-plane maneuver, not change in altitude. But yes, you're forcing the missile to suddenly re-compute an intercept out-of-plane. That means there's control lag to change direction, inertia etc. etc.

 

Is the idea to effectively roll... around the missile as it closes in? (obviously it never just stops so you never complete the roll around it, but it's like a wave curl, right?)

 

Correct.

[arteedecco]

Inertia when maneuvering does, however, not care about indicated. You spend more to do less. (Otherwise, F-15's would be going to orbit without a problem. ;) )

Maybe I'm not understanding you... we're talking about acceleration right? Because maneuvering certainly does care about indicated (more mass flow over surfaces means surfaces are more effective... sub-sonic).

 

In terms of acceleration w.r.t Inertia, ya I get you.

 

It's not the "true air speed" entering engines you're looking for. It's the mass of air. Jet engines are "breathers" - but they don't "breathe" speed, they breathe oxygen. Give them more oxygen and they'll give you more thrust. This is obviously, though, a balance against drag. But the point is that you cannot take two unknown altitudes and automatically say that the one with the faster TAS has your engines produce more thrust.

 

Yah... I thought I said "Indicated Airspeed" earlier in my post, since that's a more linear measure of mass flow than True Airspeed, but I may have poorly articulated what I was trying to convey.

 

Would you agree that the number of air (and therefore oxygen) molecules flowing into an engine at 400 IAS at sea level is roughly (not accounting for compressibility) the same as at 400 IAS at 30,000 feet, while the TAS is significantly higher at 30,000 feet than at Sea level?

[Svend_Dellepude]

Thanks for your thoughtful and detailed feedback all! @Siskin, thanks for catalyzing such a good discussion and for working to articulate your methods.

 

Let's keep things civil and as @Siskin recommended steer away from inflammatory comments. The overall goal is to provide a good resource for those of us less versed in BVR tactics.

 

I wanted to throw in some thoughts on the "crank" topic.

 

@Siskin, correct me if I'm wrong, but it seems you are saying that when nose-to-nose with the bandit (on the front-end of the engagement, no weapons fired), you use an indicated airspeed (IAS) below combat maneuvering speed (max performance / "cornering speed"), correct?

 

If I am correct in that understanding, you do that to reduce the closure rate... giving you more time to react, but primarily your goal is to give you more time from any launched, incoming missiles?

 

You combine this reduced IAS with offsetting via a "crank" maneuver, further reducing closure rate to the bandit, right? (or do you accelerate for the "crank"... I read it that you did not accelerate into the "crank" to combat speed, right?)

 

IF a missile is launched, you execute your Split-S to convert Potential Energy (PE) into Kinetic Energy (KE) and reversing course 180, still correct?

 

Now.. the others will correct me if I'm wrong, but I believe the issue they have with this technique is that this requires you to accelerate, which is slow for a couple reasons.... a.) you have to accelerate (which takes time), but b.) at reduced airspeed your aircraft takes longer to maneuver and you cannot change direction as quickly as if you started at combat speed, thereby negating some/most/all of the "gains" you got by having a reduced initial airspeed.

 

So... let's say you have a combat speed of 425 knots in the F-15C.... if you "crank" to 60 degrees your velocity vector in the direction of the bandit drops to 212.5 knots (half), but... you still maintain your forward velocity of combat speed, meaning you can change direction at the most rapid rate possible for your aircraft.

 

Keeping things simple.... let's say bandit doesn't change direction significantly after you "crank" what is the difference in times to 20 nautical miles between the two aircraft, if the bandit also maintains 425, but trucks straight on in? For this argument, assume both aircraft gain radar lock at 50 nautical miles.

 

V1 = your velocity vector in the direction of the bandit

V2 = bandit velocity vector in your direction

Vc = closure velocity (Vca === option A, Vcb === option B)

* assume Indicated airspeed === True airspeed (no wind)

 

Option A, nobody "cranks":

Vca = V1 + V2 = 425 + 425 = 850 Knots

 

Option B, YOU "crank" immediately after establishing lock, but bandit does nothing:

Vcb = V1 + V2 = 212.5 + 425 = 637.7

 

 

The difference (%) between Option A and Option B is 75%. Now... the time to 20 nautical miles from 50 nautical miles is simply, Velocity = Distance / Time... so Time (T) = Distance (d) / Velocity (v):

 

Option A (Ta), with Vca of 850 Knots:

Ta = d / v = 30nm / 850 nautical miles per hour = 30 / 850 = 0.03539 hours = 2.1178 minutes (2m : 7s), or 127.058823529416 seconds

 

Option B (Tb), with Vcb of 637.7 Knots:

Tb = 30 / 637.5 = 0.047044 hours = 2.82264 minutes (2m : 49s), or 169.411764705876 seconds

 

Tb is 33% longer than Ta... in other words... if you "crank" you get 33% more time in the engagement... plus... your vector that is 90 degrees to the oncoming bandit is 368.06079660838645 knots.

 

That portion of your vector, which is 90 degrees to the direction of the oncoming aircraft is the big part here and what you want maximized... and why the recommendation is to be faster, rather than slower in this "cranked" situation.

 

If the enemy fires and you are going laterally (90 degrees to the shot and bandit) at 368 knots... additionally... you are already at your combat (max perf.) speed, no need to accelerate to it. If you were slower... you have increased your problems... a.) you have to accelerate, b.) you have a smaller differential between your velocity away from the missile and the missile velocity towards you (e.g. you have less time, the missile has more energy).

 

Someone smart please review my math / logic and correct me if/where I'm wrong. Sorry I don't have a diagram.

 

If this is what you mean by a crank in your example you'll only get half way before you start flying away from each other.

It's a dynamic situation where the angle's change with every second, thus closure is not a constant, thus making the math a bit more difficult.

 

 

 

cheers

[EtherealN]

Remember that "maneuvering" is acceleration!

 

Not accounting for compressibility, yes, sure. And also not accounting for drag.

[arteedecco]

Crank is maintained, you don't wave side to side. Place target on radar gimbal limits, keep him there.

 

Going up and down can be useful in long-range BVR if he has fired upon you (or you believe he has fired upon you), to make his missile maneuver extra and thus bleed it of energy.

 

As you do this "crank"... won't the enemy radar contact (in both planes) gradually drift even further out to the side, since you're angle is shifting as they continue to close?

 

Seems to me that this would relate in a very very gradual bank into the bandit to maintain the appropriate angle (edge of gimbal)?

 

Also, what happens as your contact begins to drift on the bandit side? Won't he adjust heading to maintain your contact and therefore cause you to have to then adjust out (crank out more)... resulting in a shallow S-turn pattern throughout the close?

[Couladin]

The actual flight path of the aircrafts in a crank will be changed according to their speeds. The speed of each one counts.

 

If you perform the crank and the bandit is at stall sped, your movement around him will be a spiral, going closer and closer.

 

The slower you are and faster he is... actually i can't visualize this one hehe.

 

This is assuming he's trying to go straight toward you. Everything changes a lot if he cranks as well, either same way or other way.

Edited January 14, 2013 by Siskin

[EtherealN]

As you do this "crank"... won't the enemy radar contact (in both planes) gradually drift even further out to the side, since you're angle is shifting as they continue to close?

 

Yes.

Maneuver as necessary to keep him where you want him in your scope.

 

Seems to me that this would relate in a very very gradual bank into the bandit to maintain the appropriate angle (edge of gimbal)?

 

Correct.

 

Also, what happens as your contact begins to drift on the bandit side? Won't he adjust heading to maintain your contact and therefore cause you to have to then adjust out (crank out more)... resulting in a shallow S-turn pattern throughout the close?

 

Not necessarily, but yes - this is exactly where things start getting really interesting.

Doing the crank is "basics". What happens afterwards is way more complex - especially if we're talking (as should be the case in realistic simulation) minimum of 2v2 engagements but most likely larger formations.

[EtherealN]

This is assuming he's trying to go straight toward you. Everything changes a lot if he cranks as well, either same way or other way.

 

Enemy that is going straight for you is dead. He just intercepted your missile, congrats, you got a kill.

 

ALWAYS plan for him doing the right thing. And always keep in the back of your head the question "what could kill me right now?"

[arteedecco]

If this is what you mean by a crank in your example you'll only get half way before you start flying away from each other.

It's a dynamic situation where the angle's change with every second, thus closure is not a constant, thus making the math a bit more difficult.

 

 

 

cheers

 

Yep, you're completely right. I was treating it as linear, but as I wrote that all out I realized it would be a curve, not a straight line for just the reason you mention.

 

However, it still seemed illuminating to start with a basic example like that since that is where it starts.

 

Anyhow... good eye! :smilewink:

[NoJoe]

I'm not sure how much we can glean from a video of real-life BVR combat training, but there's an interesting one on Youtube about a group of Hornet pilots practicing BVR against German MiG-29s and F-4s.

 

 

Skip ahead to about 7 minutes in where they start the engagement. You can see in-cockpit video of the two Hornet pilots and hear their radio calls and commentary as they call Fox 3 (simulated, of course), crank, support to pitbull, then notch. The action starts at about 7:45 as they fire and crank.

 

The notch was surprisingly aggressive. They turn to beam the bandits, then roll inverted and descend very steeply. At 8:38 in the video one of the pilots mentions they descended about 10,000 feet in 5 to 10 seconds during the notch maneuver.

 

The video doesn't let us see any of the details, like exact headings or the radar screens, but it's a neat look at some (presumably) real-world radio calls, and it lets us sort of see what the maneuvers look like.

 

Again, not sure how much useful info we can get from this video, but at least it might be interesting to see!

 

--NoJoe

[arteedecco]

Enemy that is going straight for you is dead. He just intercepted your missile, congrats, you got a kill.

 

ALWAYS plan for him doing the right thing. And always keep in the back of your head the question "what could kill me right now?"

 

Cool, makes sense.

 

Since we've pretty well handled crank, notch, beam (to some extent), and orthogonal rolls.

 

Next questions:

 

(ref.: page 111 of the "DCS FC3 Flight Manual EN.pdf")

Raero, Rpi, Ropt, Rmnvr, Rtr, Rmin, Probability of Kill (PK), "spoiler" shot, ECM << that's what I want to talk about next

 

I know that's a a hefty list, but I'm only talking in the initial convergence and some of those go together, but all apply to initial BVR engagement tactics.

 

1. Raero (Rmax) - Range with Optimal Steering, including aircraft lofting. This is the maximum aerodynamic range the missile can fly out to and still kill a target. It assumes a non-manouvering target that maintains a constant velocity, and represents the earliest opportunity at which a target intercept can be computed.
   
2. Ropt - Max Range Probability of Intercept with Optimum Steering. Requires steering dot to be centred and also assumes non-manoeuvring, constant velocity target. (note: "dot centered")
   
3. Rpi - Max Range Probability of Intercept with Current Steering. Assumes non-manouvering target with constant velocity. (note... "with Current Steering")
   
4. Rmnvr - Max Range against a Manoeuvring Target. Assumes target executes a 4g, level turn to face away from the missile at the moment of launch.
   
5. Rtr - Range Turn and Run. Indicates the maximum launch range against a target executing an evasive turn and run maneuver at launch and is calculated using current steering. If steering closely approaches optimal steering, RPI approaches ROPT. Once the dot is centred, RPI and ROPT are the same.
   
6. Rmin - minimum missile launch distance
   

 

What is shown directly on the HUD from longest range to closest range (top to bottom) is:

top: Rpi

next: Rtr

bottom: Rmin

 

A.) Is Raero shown in any way on the HUD, or just has to be estimated by pilot? In other words... if two aircraft are closing (both locked up in STT) and the range indicator is above (further out) than Rpi... and you are M1+.. you pitch up and fire... will your shot hit if bandit chooses to come straight in without evading in any way?

 

B.) Should you generally always fire a spoiler at Rpi to get bandit defensive or dead? What if you're cranked (Rpi won't === Ropt because dot will probably be out of center).

 

C.) Is it better to fire first shot somewhere after Rpi, but before Rtr? (obviously if bandit does nothing and appears to have no indication that you are approaching / engaging, you could wait til Rtr, but that is unlikely in this case)

 

D.) ECM... ON or OFF? I know that there's a lot to this, but how to decide? I know that at about 20nm you should have it off because you've already reached "Burn Through" plus you're just advertising your position (easy azimuth).

[arteedecco]

I'm not sure how much we can glean from a video of real-life BVR combat training, but there's an interesting one on Youtube about a group of Hornet pilots practicing BVR against German MiG-29s and F-4s.

 

 

...

 

Again, not sure how much useful info we can get from this video, but at least it might be interesting to see!

 

--NoJoe

 

Well I thought it was awesome. I'm surprised they even discuss missile evasion tactics at all, but you're right they do say "notch". @GGTharos has mentioned that lots of it is non-classified and public domain... I never would have picked that stuff up before going through this stuff with FC3.

 

Neat! +1

[NoJoe]

Well I thought it was awesome. I'm surprised they even discuss missile evasion tactics at all, but you're right they do say "notch". @GGTharos has mentioned that lots of it is non-classified and public domain... I never would have picked that stuff up before going through this stuff with FC3.

 

Neat! +1

 

Yeah, it surprises me too that the video and this stuff is available publicly. However, maybe these are older tactics that no longer necessarily apply exactly to more modern ARH missiles? I don't know. It's fun to watch, though. :D

 

Thanks to all in this thread; it's fascinating to read and very informative! Especially the revelation of not slowing down during the crank (I had learned from a Frugal's World tactics thread which advocated the use of brakes). I'm looking forward to trying these tactics in Falcon and FC3!

 

--NoJoe

[willzah1313]

That video just makes me want the Hornet even more :( or a Mig-29

[ZaltysZ]

Now, what i'm about to say, is what i've been doing so far, now i need to digest the new information and see exactly what i change.

 

Every aircraft has a [corner] speed turning at which has the largest directional change rate. Flying below that speed gives you lesser directional change rate (and less Gs you are able to pull), going above it also gives lesser directional change rate despite high Gs (this is because modern aircraft are G limited, so you will have restriction on degrees/s at high speeds, because of that G limit).

 

Flying at (or slightly above) corner speeds gives you ability to quickly initiate max rate turn. Such turn is very disliked by anything flying on collision course, because it forces intercepting object do the largest changes in its course (pull lots of Gs) and waste lots of energy. Consider these points:

 

1) Missile has small control surfaces, which are effective only at high speeds. Slow missile = useless missile.

2) Missile has working motor only at initial stages of its flight. This means, that it mostly bleeds energy at final stages and surely does not like anything what helps it to bleed more.

3) Missile has a G limit too. It is something like 30-40 Gs for modern missiles.

4) Depending on rage to maneuvering target, missile might need to pull something like 5 times more Gs than target is pulling, if it wants to stay on collision course. It might not be possible due to lack of energy (in the most cases of BVR) or even due to structural limits.

 

So basically, you should never go below corner speed while in combat. It is like insurance against unforeseen things. Flying at it is a good habit, which helps a lot in non sterile environments. Also it helps a lot in defeating the missile in energy department. It should be a lower bound speed at your tactics, and probably a upper bound (as I understand your intention to minimize rate of closure).

[GGTharos]

A.) Is Raero shown in any way on the HUD, or just has to be estimated by pilot? In other words... if two aircraft are closing (both locked up in STT) and the range indicator is above (further out) than Rpi... and you are M1+.. you pitch up and fire... will your shot hit if bandit chooses to come straight in without evading in any way?

 

Although it may be configurable in software, all we see in the RL operation manuals so far are the indications that you see, for the aircrafts modeled in-game.

 

B.) Should you generally always fire a spoiler at Rpi to get bandit defensive or dead? What if you're cranked (Rpi won't === Ropt because dot will probably be out of center).

 

He who fires first wins the fight. That won't always end up being true, but generally that is how things work.

 

C.) Is it better to fire first shot somewhere after Rpi, but before Rtr? (obviously if bandit does nothing and appears to have no indication that you are approaching / engaging, you could wait til Rtr, but that is unlikely in this case)

 

THat depends on what you're trying to accomplish and what your bandit is trying to accomplish :)

 

D.) ECM... ON or OFF? I know that there's a lot to this, but how to decide? I know that at about 20nm you should have it off because you've already reached "Burn Through" plus you're just advertising your position (easy azimuth).

 

ECM prevents your opponent from accurately knowing your position (range) outside of 22-28nm. Inside this range it's useless. Outside this range, use it to whatever tactical advantage you think it may give you, but if your ECM is on you won't be hiding in a notch.

[GGTharos]

There's a video out there showing one f-16 notching another, in RL, right in the HuD.

 

Well I thought it was awesome. I'm surprised they even discuss missile evasion tactics at all, but you're right they do say "notch". @GGTharos has mentioned that lots of it is non-classified and public domain... I never would have picked that stuff up before going through this stuff with FC3.

 

Neat! +1