Soviet Testing of F-5E after Fall of Saigon

[silverdevil]

i read this article this morning. pretty interesting. especially for those of you that like the Tiger.

https://theaviationgeekclub.com/soviet-pilot-who-test-flew-captured-f-5-against-mig-21-mig-23-explains-why-the-tiger-beat-the-fishbed-flogger-in-every-engagement/

[Fairey Gannet]

On 10/14/2021 at 2:03 PM, silverdevil said:

i read this article this morning. pretty interesting. especially for those of you that like the Tiger.

https://theaviationgeekclub.com/soviet-pilot-who-test-flew-captured-f-5-against-mig-21-mig-23-explains-why-the-tiger-beat-the-fishbed-flogger-in-every-engagement/

Good read. I will return the kindness with some more Tiger stuff.

https://www.the-northrop-f-5-enthusiast-page.info

[SorelRo]

That's such a good read. And also it's interesting if you read about the US pilots flying to Mig-21 and saying how it can hold its own against maneuvering planes. 

 

https://www.key.aero/sites/keyaero/files/node_forum/2010/07/15/MAKING THE BEST OF MiG-21 w.pdf

[Fairey Gannet]

8 minutes ago, SorelRo said:

That's such a good read. And also it's interesting if you read about the US pilots flying to Mig-21 and saying how it can hold its own against maneuvering planes. 

 

https://www.key.aero/sites/keyaero/files/node_forum/2010/07/15/MAKING THE BEST OF MiG-21 w.pdf

Here, I think it might be interesting.

http://pogoarchives.org/labyrinth/09/08.pdf

[SorelRo]

Holly smokes, that's a good read. Gonna put it on my Kindle

[Fairey Gannet]

8 hours ago, SorelRo said:

Holly smokes, that's a good read. Gonna put it on my Kindle

Thank you!  Now, I have something else...

https://pdfcoffee.com/northrop-f5-case-study-in-aircraft-design-pdf-free.html

Edited October 16, 2021 by Fairey Gannet

[DmitriKozlowsky]

A combat pilot intimately familiar and combat experienced in F-5E, will comfortable take on and defeat a greenhorn in Mig-29SMT or SU-27.   An experienced combat pilot in Mig-29, will kill a USAF 2Lt. out of flight school and conversion training on F-22 or F-35, more times then he would loose.  A Marine or Navy WWII combat F-4U Corsair pilot in Korean thing, shot down a NorK or Chinese Mig-15. A guns kill by a radial prop from WWII, on 1st gen turbojet fighter.   A really rare, really talented Vietnamese Mig-21PF(?) 'Colonel Trang" or similar had kills on F-4s of USAF and almost killed Randy 'Duke' Cunningham and his WSO. They were outflown and outfought by this guy in his puny Mig-21 export (probably a Chinese clone of a Russian Mig-21 export), and they were in F-4B or C of the Navy and had Sparrows and Sidewinders, and could not get him, so they separated.  Then man in cockpit , often counts more then plane the cockpit is attached to. 

Israelis studied captured Syrian Mig-23. They thought that at high altitude and high speed, Mig-23 could have an energy advantage over then F-16A Block 10 of IAF. They were also impressed with radar integrated into HUD concept. Something Western Air Forces never quite got. Maybe they had too much on HUDs already.

Point is, you as pilot fight the aircraft you have, not the aircraft you wish you had.

[SorelRo]

On 11/10/2021 at 6:32 AM, DmitriKozlowsky said:

A combat pilot intimately familiar and combat experienced in F-5E, will comfortable take on and defeat a greenhorn in Mig-29SMT or SU-27.   An experienced combat pilot in Mig-29, will kill a USAF 2Lt. out of flight school and conversion training on F-22 or F-35, more times then he would loose.  A Marine or Navy WWII combat F-4U Corsair pilot in Korean thing, shot down a NorK or Chinese Mig-15. A guns kill by a radial prop from WWII, on 1st gen turbojet fighter.   A really rare, really talented Vietnamese Mig-21PF(?) 'Colonel Trang" or similar had kills on F-4s of USAF and almost killed Randy 'Duke' Cunningham and his WSO. They were outflown and outfought by this guy in his puny Mig-21 export (probably a Chinese clone of a Russian Mig-21 export), and they were in F-4B or C of the Navy and had Sparrows and Sidewinders, and could not get him, so they separated.  Then man in cockpit , often counts more then plane the cockpit is attached to. 

Israelis studied captured Syrian Mig-23. They thought that at high altitude and high speed, Mig-23 could have an energy advantage over then F-16A Block 10 of IAF. They were also impressed with radar integrated into HUD concept. Something Western Air Forces never quite got. Maybe they had too much on HUDs already.

Point is, you as pilot fight the aircraft you have, not the aircraft you wish you had.

Doesn't matter what violin you play, it's all about the violinist, eh? 

[DmitriKozlowsky]

1 hour ago, SorelRo said:

Doesn't matter what violin you play, it's all about the violinist, eh? 

I bow to you concision. You said in short sentence, what I said in a long paragraph. Which may mean I have an ego problem, and you do not.

[LowRider88]

For those who play offline against the AI, and are also annoyed with how the AI cheats and flys like a UFO at higher skill levels, this article has helped me understand which DCS AI skill level may be the most realistic.

In the article the F-5 pilot was able to defeat the MiG-21 in under 4 minutes (the article claims defeating the 23 took longer than the 21, which was about 4 to 5 mins).

When I set the AI Mig-21 skill level to Veteran and take it on with the F-5, the end result is that we wind up in a never ending series of rolling scissors or vertical loops, with the 21 always just slightly out of my cone of fire, until it runs out of fuel.

When I set the AI MiG-21 skill level to Trained, it took me about 4 mins to kill it, but the first time I had it in my reticle for a tracking shot was around 3 mins.  That first tracking time I suppose would equate to an eletrontic kill in the article.

I suppose result will vary, as some other pilots may be better than me.  I would be curious if anyone else in this scenario is able to kill the 21 in under 4 mins at Veteran level, or if they also go into an infinite loop until vapour time as well.

BTW, I set the match up to begin around 5000ft.

 

This discovery has improved my enjoyment of DCS.

Previously, when flying an F-5 against a Veteran MiG-29, it was extremely frustrating.  The infinite loop to vapour time in this case was the 29 always out out rating me in the horizontal turn, me aggressively forcing him in front with a scissors fight, only to have him climb out of range, go around and out rate me again.  Taking a shot in this scenario is never possible.  It always ends with the 29 ejecting, out of fuel, and me with all my ammo.

With the 29's skill level at Trained, there is still some challenge, but in this case a firing shot is actually possible.

 

So in summary, from my perspective, any AI skill level above trained is just UFO, unwinnable arcade.

DCS should just remove those skill levels, or else change the name to Digitial Combat Game.

[LeCuvier]

@LowRider88:
I'm not an experienced F-5E pilot, and I'm trying to replicate what you say, dogfighting off-line against a "Trained" AI MiG-21bis. The first couple of rounds saw me going down burning. So I changed my tactics. I avoid pulling too much G so I stay close to 300 kts. The action starts at about 35000 ft altitude but the dance rapidly descends to very low altitude and after several circles I get into a good position, and I either get him with the guns or he just crashes. The difficult part is not to lose him or stall when he climbs like a rocket, which is what he does when his position gets critical.

Questions:
1. I keep the flaps in "Auto". Is that ok?
2. I read about "manoeuvring flaps", but I find no command binding for that, no matter what spelling of "manoeuvring" I look for. Is there any?

Edited December 22, 2021 by LeCuvier

[razo+r]

9 minutes ago, LeCuvier said:

@LowRider88:
I'm not an experienced F-5E pilot, and I'm trying to replicate what you say, dogfighting off-line against a "Trained" AI MiG-21bis. The first couple of rounds saw me going down burning. So I changed my tactics. I avoid pulling too much G so I stay close to 300 kts. The action starts at about 35000 ft altitude but the dance rapidly descends to very low altitude and after several circles I get into a good position, and I either get him with the guns or he just crashes. The difficult part is not to lose him or stall when he climbs like a rocket, which is what he does when his position gets critical.

Questions:
1. I keep the flaps in "Auto". Is that ok?
2. I read about "manoeuvring flaps", but I find no command binding for that, no matter what spelling of "manoeuvring" I look for. Is there any?

 

Auto is basically maneuvering flaps. It adjusts the position depending on AoA. 

Using auto is alright, though I feel like you can switch between auto and up to get a bit more out of the aircraft depending on the situation. 

[LowRider88]

7 hours ago, LeCuvier said:

@LowRider88:
I'm not an experienced F-5E pilot, and I'm trying to replicate what you say, dogfighting off-line against a "Trained" AI MiG-21bis. The first couple of rounds saw me going down burning. So I changed my tactics. I avoid pulling too much G so I stay close to 300 kts. The action starts at about 35000 ft altitude but the dance rapidly descends to very low altitude and after several circles I get into a good position, and I either get him with the guns or he just crashes. The difficult part is not to lose him or stall when he climbs like a rocket, which is what he does when his position gets critical.

Questions:
1. I keep the flaps in "Auto". Is that ok?
2. I read about "manoeuvring flaps", but I find no command binding for that, no matter what spelling of "manoeuvring" I look for. Is there any?

 

Hi LeCuvier, Thanks very much for also trying out the scenario and providing your feedback.

If you get a chance I would also like to know if you could defeat the 21 in a 5, when the 21 AI is set to Veteran, and if so how long it takes (I.e under 4 mins as in the article).

 

As razo+r replied, Autoflaps is similar to Maneuvering flaps.  There is a copy of the F-5E actual flight manual linked somewhere here in this forum, complete with OCR text searching.  In the manual, you can see that both are a form of flap angle automation, but just with different angle settings.  They control not only the standard plain trailing edge flaps, but also the leading edge flaps.  Maneuvering flaps was for the earlier F-5E-1 version and Autoflaps is for the F-5E-3 version we currently have in DCS.

razo+r is right that some DCS pilots like to switch between auto and up settings during a battle for better control.  For me personally, I found I can dogfight entirely in auto, as during some AoA and speed regimes, the autoflaps will retract on their own, and I personally don't notice the difference.  I only revert to Up position when I am taxiing to improve range and endurance, since I read some where that there could be some slight flutter of the autoflaps that could reduce efficiency when flying in a straight line.

 

My findings are somewhat similar to yours.

 

Since the F-5E has both lower thrust to weight and wing area than the MiG-21, it is hard for it to challenge the MiG high up, just as the article implied.  The 5 does have LERXs, but these I believe mainly help when you have AoA, where they can prevent speed loss.  But at high altitude, more of its speed may be required for level flight than high AOA, given the low thrust to weight ratio.  There may not be enough air density up there for the LERXs to be useful.  So the fight eventually trends lower and lower, where the 5 has the advantage.

At high altitude, if the 21 gets behind you, or if you just want to save yourself some time, you can just go for a spiral dive down to the more advantageous lower altitude.  The spiral helps prevent letting the 21 use its missiles more guns on you when diving.

if you don't know what the spiral dive looks like, you can look up GVad's YouTube channel, in a recent video with him in a Mirage against an F-16 AI, the 16 does a spiral dive near the end of the video.  Oh, but you don't seem to be new to the forum and may know already, so never mind

 

Whenever I haven't flown the F-5 in a while I always also pull too many Gs, but the good tip you can read in this forum is that as soon as you see your canopy frame shaking, you are pulling too much and are increasing drag, bleeding speed, with out much more angle-off-tail gain.

 

I noticed when down low that there may be very specific scenarios when the AI will crash.  Against something as maneuverable as a MiG-29, it is when we are in a (1 circle) fight, about to make a head to head pass, I am just feet above the ground, the AI is higher than me, and then I pull upwards, towards the AI, during the head on pass.  The AI will aggressively try to close the angle off nose, which forces it to dive beyond its ability to pull up.  It happens so often it is no longer enjoyable, so even though pulling up in a situation like that may be desirable, I avoid it just to get a more meaningful kill from the AI.  The MiG-21 AI seems to lawndart more frequently than the 29, just because it is less maneuverable, but still has such a high thrust to weight ratio.

 

In earlier DCS versions, or when playing with 21 AI set to Rookie, I noticed the 21 always was still within reach.  I am not sure if the AI was improved in recent versions, or if it is because of the trained AI setting that I use now, but I noticed recently that if I miss the 21 with both of my F-5 missiles, the 21 sometimes will climb and extend away from me and leave the fight.  So annoying, but I like that more since it is realistic.  In this case I have to hunt it with AWACS or GCi, hoping I don't loose all my fuel while keeping up.

 

I also had trouble initially with stalling during a chase on a climbing 21.  The trick I use now against the AI is to climb only enough to keep the 21 in sight, keep its angle off my nose below 90 degrees, and prevent it from getting enough separation to turn back into me.

I.e, I am using lag pursuit in the climb.

I usually reclaim the advantage when the 21 loops back down, in which case I switch to lead pursuit.

More important is to close off your horizontal compass angle during these climbs, also to close it off from turning into you.

 

Thanks again LeCuvier for trying out the experiment

 

[razo+r]

16 minutes ago, LowRider88 said:

 

razo+r is right that some DCS pilots like to switch between auto and up settings during a battle for better control.  For me personally, I found I can dogfight entirely in auto, as during some AoA and speed regimes, the autoflaps will retract on their own, and I personally don't notice the difference.  I only revert to Up position when I am taxiing to improve range and endurance, since I read some where that there could be some slight flutter of the autoflaps that could reduce efficiency when flying in a straight line.

Auto is sufficient for most times, but putting it to up brings some advantages in specific conditions.

A wing generates more lift with flaps, but the flaps also reduce the maximum AoA you can achieve. So putting the flaps up might give you less lift, but you can pull more AoA which might be usefull sometimes if you need that tiny extra bit of pulling.

16 minutes ago, LowRider88 said:

The 5 does have LERXs, but these I believe mainly help when you have AoA, where they can prevent speed loss.

They help to delay the airflow separation from the wing, they delay a stall. They don't prevent speed loss. In contrary, you could argue, since they let you increase your AoA, they increase the speed loss.

16 minutes ago, LowRider88 said:

 

 But at high altitude, more of its speed may be required for level flight than high AOA, given the low thrust to weight ratio.  There may not be enough air density up there for the LERXs to be useful.  So the fight eventually trends lower and lower, where the 5 has the advantage.

 

As above, LERX help keeping the airflow on your wings and delay the stall. They'll simply let you get more AoA compared to the same wing with no LERX.

Edited December 22, 2021 by razo+r

[LowRider88]

10 minutes ago, razo+r said:

Auto is sufficient for most times, but putting it to up brings some advantages in specific conditions.

A wing generates more lift with flaps, but the flaps also reduce the maximum AoA you can achieve. So putting the flaps up might give you less lift, but you can pull more AoA which might be usefull sometimes if you need that tiny extra bit of pulling.

They help to delay the airflow separation from the wing, they delay a stall. They don't prevent speed loss. In contrary, you could argue, since they let you increase your AoA, they increase the speed loss.

As above, LERX help keeping the airflow on your wings and delay the stall. They'll simply let you get more AoA compared to the same wing with no LERX.

 

Interesting.  I have never required that myself, but it is worth experiementing to confirm.

I currently don't agree that flaps decrease max AoA.  If they did, why bother extending during a landing?  You get max AoA and min stall speed during a landing, do you not?

Unless you are referring to instantaneous turn rate.  If so, the action here (after the instantaneous turn) seems to be to switch to auto from up, rather than the other way around.

 

I disagree about LERX increasing speed loss.  If so, why install them?  The violent vortices they produce help to keep the airflow on the wings, and so lower induced drag.  If you try to pull the same turn as the 5 in a 21 with more wing area, the 21 will stall first because it has more induced drag and greater speed loss.

[razo+r]

11 minutes ago, LowRider88 said:

 

I currently don't agree that flaps decrease max AoA.  If they did, why bother extending during a landing?

 

Because you don't go for max AoA at landing. 

At landing, you want minimum kinetic energy. To achieve this, you extend flaps, which in turn increases your lift, which again lets you fly slower. 

Yes, maximum AoA would give you maximum lift, but it would be very unsafe. Increase pitch and it stalls. A bit of wind and it stalls. Bit of bank / load and it stalls. Usually your approach speed is something like 1.3*Vs.

You can also see it ingame. For landing, you aim for the AoA which gives you the green doughnut. That one is not the max. AoA though. You can still pull back and get the red indication until you reach the point where you cannot increase your AoA anymore. That is the point when you reached max AoA.

 

 

And I must add a detail/correction for my statement. Depending on the airfoil, flaps only can decrease max. achievable AoA. LEF on the other hand can increase max. achievable AoA. If you then combine them, you will be able to get more lift while still being able to achieve the less, same or more AoA.

Now ingame, I've tried it (in a non-scientifical way) and without flaps and LEF deployed it lets you pull a few degrees more than with both deployed.

 

11 minutes ago, LowRider88 said:

You get max AoA and min stall speed during a landing, do you not?

No. You don't go for stall speed at a landing in the first place and thus also not max AoA. You usually get those in level flight when you train stall recovery.

Stall speed also depends on the configuration. Clean config and you have a higher stall speed. Flaps and all stuff deployed and you have a lower stall speed. They do not have to occur at the same AoA though.

11 minutes ago, LowRider88 said:

I disagree about LERX increasing speed loss.  If so, why install them?  The violent vortices they produce help to keep the airflow on the wings, and so lower induced drag.

LERX allows you to pull more AoA for the reason you wrote, they keep the airflow on the wings. For a given wing shape, more AoA means more lift. More lift equals more drag. So they do NOT lower induced drag, they increase it. And what increasing drag means should be clear.

 

 

[LowRider88]

40 minutes ago, razo+r said:

Because you don't go for max AoA at landing. 

At landing, you want minimum kinetic energy. To achieve this, you extend flaps, which in turn increases your lift, which again lets you fly slower. 

Yes, maximum AoA would give you maximum lift, but it would be very unsafe. Increase pitch and it stalls. A bit of wind and it stalls. Bit of bank / load and it stalls. Usually your approach speed is something like 1.3*Vs.

You can also see it ingame. For landing, you aim for the AoA which gives you the green doughnut. That one is not the max. AoA though. You can still pull back and get the red indication until you reach the point where you cannot increase your AoA anymore. That is the point when you reached max AoA.

 

 

And I must add a detail/correction for my statement. Depending on the airfoil, flaps only can decrease max. achievable AoA. LEF on the other hand can increase max. achievable AoA. If you then combine them, you will be able to get more lift while still being able to achieve the less, same or more AoA.

Now ingame, I've tried it (in a non-scientifical way) and without flaps and LEF deployed it lets you pull a few degrees more than with both deployed.

 

No. You don't go for stall speed at a landing in the first place and thus also not max AoA. You usually get those in level flight when you train stall recovery.

Stall speed also depends on the configuration. Clean config and you have a higher stall speed. Flaps and all stuff deployed and you have a lower stall speed. They do not have to occur at the same AoA though.

LERX allows you to pull more AoA for the reason you wrote, they keep the airflow on the wings. For a given wing shape, more AoA means more lift. More lift equals more drag. So they do NOT lower induced drag, they increase it. And what increasing drag means should be clear.

 

 

Your diagram was a good clarification, but not entirely helpful.  Was that from the F-5E manual?

From Figure 1-52 from the manual, I see no example where either UP or AUTO settings for the F-5E-3 allow you to select slots only, or flaps only.  It is always both working in conjunction together at various degrees.  So the extreme singular cases in your diagram are not met in the F-5, and any F-5 flap extension setting always produces more AoA and lift than with the UP setting.

Your in game example is not the same as your diagram.  Red on the landing index indicator with flaps down is not the same as the max AoA you are referring to with flaps up.  In game, what would happen when you have red on the index and then put your flaps up?

You say there are some cases where UP setting produces less lift but more AoA (which based on figure 1-52 seems to be untrue).  That is like a sliding situation, where the plane is more like going into a slight tangent, but you try to point the nose even further for a better shot.  But that doesn't seem worthwhile to me.  You may get a sudden snapshot, but unless you have quick reflexes to switch back to auto, the loss of lift immediately causes you to lose any angle gains.  Better to let the automation handle this.

If you have examples of what conditions the UP works for tighter turns, perhaps you can clarify.  Unless you prefer to keep it a secret.

 

You are talking about the speed loss on a single plane with LERX, between pulling AoA and flying straight, whereas I am talking about two planes pulling AoA, one with LERX and the other without.  The speed loss is the stalling in the 21 with no LERXs in the same turn, compared to a 5 with LERX.  Once a 21 pulls a high G maneuver, and the instantaneous turn degrades, it is like a slow moving rock in the sky.  That is the speed loss I am referring to.  The 5 has less of this problem because of the LERXs.  

 

Some of your corrections are technically correct, but they distract from the original spirit of our experiment conversation.

 

If I were to say there was a use for UP flaps settings it would be for trying to invoke a near stall condition, like when trying to pull off a WingOver, Hammerhead or J-Turn.  Interesting.  Something worth experimenting with.

[Snappy]

I think you have to let go of the notion that there is such a thing is as stall speed. I know the concept is still somewhat popular in general aviation, but its not the speed or lack of speed that causes the stall, its the exceedence of a critical AOA.

So its not as important whether plane A or B loses more speed in a high G turn (non sustained). If plane A due to its wingshape or due to not having leading edge extensions has a lower critical angle of attack it will stall first, while plane B with a different wingshape and /or leading extensions can pull to that AOA and still not stall.

The use of the Flap UP position is, if you want to rapidly accelerate and regain energy. Then you can unload the aircraft (i.e.  push to <1G, preferable close to 0G) and pull up the flaps,because thats more efficient.

You want to reduce induced drag (and indirectly therefore lift) for maximum acceleration and so you retract  all devices than generate additional lift(and drag). The plane can't sense what you want to do and auto-flaps would aim to provide you  with adequate lift, which under these circumstance is exactly not what you want. You use the Flaps UP position for that.

But of course you need to have some altitude for it. Obviously cant do it at tree top height.

Regards,

Snappy

Edited December 22, 2021 by Snappy

[LeCuvier]

@LowRider88: I'm still finding it very difficultto defeat the MiG-21 AI even at "Trained" level. Most of the time I can't even hit it and it crashes because it's out of fuel. And typically, I'm very close to do the same when I get there. Just now, I managed to hit it with 20mm HEI after 3:45 but it only crashed at 12:00 and  although I got credit for the kill I'm sure that it was out of fuel. It did not try to fight me in a horizontal turning fight but kept manoeuvring in the vertical.

[LowRider88]

1 hour ago, Snappy said:

I think you have to let go of the notion that there is such a thing is as stall speed. I know the concept is still somewhat popular in general aviation, but its not the speed or lack of speed that causes the stall, its the exceedence of a critical AOA.

So its not as important whether plane A or B loses more speed in a high G turn (non sustained). If plane A due to its wingshape or due to not having leading edge extensions has a lower critical angle of attack it will stall first, while plane B with a different wingshape and /or leading extensions can pull to that AOA and still not stall.

The use of the Flap UP position is, if you want to rapidly accelerate and regain energy. Then you can unload the aircraft (i.e.  push to <1G, preferable close to 0G) and pull up the flaps,because thats more efficient.

You want to reduce induced drag (and indirectly therefore lift) for maximum acceleration and so you retract  all devices than generate additional lift(and drag). The plane can't sense what you want to do and auto-flaps would aim to provide you  with adequate lift, which under these circumstance is exactly not what you want. You use the Flaps UP position for that.

But of course you need to have some altitude for it. Obviously cant do it at tree top height.

Regards,

Snappy

 

You are literally trying to tell me that stall speed does not exist?  Please look at Figure 6-1 in the manual.  Those are not subjective, arbitrary numbers.  So what proof do you have that stall speeds are irrelevant?  Yes, critical AoA is associated to stall, but so is the stall speed.  Air over the wings is dependent on airflow in general, not just plan form.  When have you stalled in an F-5 and still had higher than stall speed?

And why are you also focusing on the speed loss leading up to the stall, while I was referring the loss of speed resulting from stalling?

Seems a bit off topic.  Bottom line - in the same tightness of turn, the 21 will stall before the 5, and as a result will have loss of speed in comparison.

 

Your suggested usage of the UP flaps in combat is completely different than what razo-r was describing, in which he said he could get additional pull, which I doubt, given the Figure 1-52, and his own diagram.

I am skeptical I would use your technique in combat.  The only time this might be useful would be perhaps:

- to chase someone, which is hardly ACM/BFM.

- in an energy fight, when I might want to extend away.  But here, how much do you buy with the UP flaps than what AUTO provides after unloading?

Or do you mean you want to regain energy quickly, from being close to a stall condition?  If so, pulling up your flaps at that point is probably a bad idea.  Maybe you can provide more practical usage examples, or cite actual increases in acceleration.

2 hours ago, LeCuvier said:

@LowRider88: I'm still finding it very difficultto defeat the MiG-21 AI even at "Trained" level. Most of the time I can't even hit it and it crashes because it's out of fuel. And typically, I'm very close to do the same when I get there. Just now, I managed to hit it with 20mm HEI after 3:45 but it only crashed at 12:00 and  although I got credit for the kill I'm sure that it was out of fuel. It did not try to fight me in a horizontal turning fight but kept manoeuvring in the vertical.

Thanks LeCuvier for trying again.  I am the same, the 21 always does vertical loops or scissors on me too.

The only difference I have is, when I do hit it with guns, the 21 almost always smokes and takes less than a minute for the AI pilot to eject as a result.

But Thanks for experimenting!

 

[razo+r]

8 hours ago, LowRider88 said:

Your diagram was a good clarification, but not entirely helpful.  Was that from the F-5E manual?

Excuse me I should have labeled it. No, it's a general diagram not related to the F-5. Different design choices result in different curves.

8 hours ago, LowRider88 said:

From Figure 1-52 from the manual, I see no example where either UP or AUTO settings for the F-5E-3 allow you to select slots only, or flaps only.  It is always both working in conjunction together at various degrees.  So the extreme singular cases in your diagram are not met in the F-5, and any F-5 flap extension setting always produces more AoA and lift than with the UP setting.

You could do that by pulling the CB for whatever flight control surface you want. Good for experimenting, but not more.

8 hours ago, LowRider88 said:

Your in game example is not the same as your diagram.  Red on the landing index indicator with flaps down is not the same as the max AoA you are referring to with flaps up.  In game, what would happen when you have red on the index and then put your flaps up?

You might be mixing it up a bit or I don't fully understand what you want to say here. You can still go to max AoA with flaps and without flaps. The value of max AoA with flaps is different than that without flaps.

Ingame, it would allow you to pull a bit more AoA, but would probably start descending as you have less lift. Other than the general effect on the behaviour when pulling, I haven't really tested it.

8 hours ago, LowRider88 said:

You say there are some cases where UP setting produces less lift but more AoA (which based on figure 1-52 seems to be untrue).  That is like a sliding situation, where the plane is more like going into a slight tangent, but you try to point the nose even further for a better shot.  But that doesn't seem worthwhile to me.  You may get a sudden snapshot, but unless you have quick reflexes to switch back to auto, the loss of lift immediately causes you to lose any angle gains.  Better to let the automation handle this.

8 hours ago, LowRider88 said:

If you have examples of what conditions the UP works for tighter turns, perhaps you can clarify.  Unless you prefer to keep it a secret.

It's only about "snapshots". Especially against AI who fly in constant loops you may find yourself having him always in the pipper but never above so you can retract flaps for more AoA and lead the guns. It's not much more useful than that.

If you want to have a lot of turnrate you need lift (and engine power). So the more flaps the more turnrate...

8 hours ago, LowRider88 said:

 

You are talking about the speed loss on a single plane with LERX, between pulling AoA and flying straight, whereas I am talking about two planes pulling AoA, one with LERX and the other without.  The speed loss is the stalling in the 21 with no LERXs in the same turn, compared to a 5 with LERX.  Once a 21 pulls a high G maneuver, and the instantaneous turn degrades, it is like a slow moving rock in the sky.  That is the speed loss I am referring to.  The 5 has less of this problem because of the LERXs.  

You do realise though that more than just LERX do play a role in the rate of speed loss, right? LERX simply give you more control at higher AoA. And they also add a drag at higher AoA. But even that additional drag might simply be not enough to create as much drag as a Mig can, especially when it stalls and then becomes a flying brick with the wings almost perpendicular to the airflow.

Your general understanding of LERX is a tad wrong. They do add drag, they do not remove it as you said. If you had a F-5 without LERX, it would probably lose even less energy as it won't have the additional drag that LERX create.

Your comparsion doesn't make a lot of sense as you compare two completely different aircraft with different designs. If you were to compare an F-5 with and without LERX, that would make a whole lot more sense. 

5 hours ago, LowRider88 said:

You are literally trying to tell me that stall speed does not exist?  Please look at Figure 6-1 in the manual.  Those are not subjective, arbitrary numbers.  So what proof do you have that stall speeds are irrelevant?  Yes, critical AoA is associated to stall, but so is the stall speed.  Air over the wings is dependent on airflow in general, not just plan form.  When have you stalled in an F-5 and still had higher than stall speed?

Stall speed changes, critical AoA does not. You are more interested in the angle at which your aircraft stalls (which is why you have an AoA gauge and indicator), but luckily, this AoA is exceeded at a specific (variable) speed. And stall speed are usually calculated in a such way that you get the highest or the exact stall speed. Stalling at a speed higher than that from the manual is or should only be possible when your wing is contaminated, broken or in any other way changed.

5 hours ago, LowRider88 said:

And why are you also focusing on the speed loss leading up to the stall, while I was referring the loss of speed resulting from stalling?

Seems a bit off topic.  Bottom line - in the same tightness of turn, the 21 will stall before the 5, and as a result will have loss of speed in comparison.

Again, different designs have different properties... Mig has a lower stalling angle to begin with.

5 hours ago, LowRider88 said:

 

Your suggested usage of the UP flaps in combat is completely different than what razo-r was describing, in which he said he could get additional pull, which I doubt, given the Figure 1-52, and his own diagram.

The diagram is only a general diagram. If you want to actually know/feel it, you have to test it.

 

[Snappy]

9 hours ago, LowRider88 said:

You are literally trying to tell me that stall speed does not exist?  Please look at Figure 6-1 in the manual.  Those are not subjective, arbitrary numbers.  So what proof do you have that stall speeds are irrelevant?  Yes, critical AoA is associated to stall, but so is the stall speed.  Air over the wings is dependent on airflow in general, not just plan form.  When have you stalled in an F-5 and still had higher than stall speed?

 

You misunderstood me . I didn't say there are no stall speeds, but that aviation is moving a away from the concept of  a fix stall speed. Because the stall speeds you can find in some aircraft manuals are only ever true under specific conditions (1G, specific aircraft mass,configuration,  center of gravity etc.).So they are very subjective. As soon as conditions change, the speeds are no longer true .

You can stall an aircraft at any speed, yes read that again, any speed  - as long as you can generate sufficient G to reach and exceed critical AOA.

If you fly a cessna 172 or similar you usually dont need to concern yourself with more than 1- 2 G during the entire flight, but even at "only" 2G , stall would already occur at a very different speed than under 1G, which illustrates why the concept of  "fix" stall speeds has limited applicability.

It is useful for calculating safe approach speeds and It has applications in regards to certification of aircrafts, but thats entirely a different matter.

Air combat is seldom performed at 1 G.  

9 hours ago, LowRider88 said:

 

And why are you also focusing on the speed loss leading up to the stall, while I was referring the loss of speed resulting from stalling?

Seems a bit off topic.  Bottom line - in the same tightness of turn, the 21 will stall before the 5, and as a result will have loss of speed in comparison.

 

You still don't seem to understand that the Mig in your example does not have a speed loss from stalling. It has a speed loss because its wing generates too much drag if its loaded up too much in a tight turn. 

9 hours ago, LowRider88 said:

Your suggested usage of the UP flaps in combat is completely different than what razo-r was describing, in which he said he could get additional pull, which I doubt, given the Figure 1-52, and his own diagram.

I am skeptical I would use your technique in combat.  The only time this might be useful would be perhaps:

- to chase someone, which is hardly ACM/BFM.

- in an energy fight, when I might want to extend away.  But here, how much do you buy with the UP flaps than what AUTO provides after unloading?

Or do you mean you want to regain energy quickly, from being close to a stall condition?  If so, pulling up your flaps at that point is probably a bad idea.  Maybe you can provide more practical usage examples, or cite actual increases in acceleration.

No I dont mean regaining energy  from a close-to-stall condition, in that situation it would be a bad idea to retract the leading and trailing edge devices as you are already close to critical AOA.

I meant unloading for separation or regaining energy in a fight. Yes, in BFM/ACM.There are uses for it.

Be sceptical as much as you want, but separating from a fight  and/ or regaining energy is a part  of BFM/ACM, as is turning.

Don't have to believe me, check out the Navy CNATRA P-825 / 826  docs on the internet, which are publicly available  . Read the sections about unloaded acceleration and "bug out" which is the navy's term for separting.There are reasons for it.
Alternatively check out the Air Force' s AETC TTP11-1 .

The above mentioned official documents contain BFM/AM theory for both services.

As for how much you gain, by FLAPS UP, well,  for a separation or energy regain you normally want as quick acceleration as possible and me , I wouldn't leave the Flaps and Slats hanging out, producing induced drag which is exactly what you're trying to get rid off in order to maximize acceleration.

Anyway, I'm out at this point. @razo+r seems to have more patience & energy than I do

Regards,

Snappy

Edited December 23, 2021 by Snappy

[LowRider88]

5 hours ago, razo+r said:

Excuse me I should have labeled it. No, it's a general diagram not related to the F-5. Different design choices result in different curves.

You could do that by pulling the CB for whatever flight control surface you want. Good for experimenting, but not more.

You might be mixing it up a bit or I don't fully understand what you want to say here. You can still go to max AoA with flaps and without flaps. The value of max AoA with flaps is different than that without flaps.

Ingame, it would allow you to pull a bit more AoA, but would probably start descending as you have less lift. Other than the general effect on the behaviour when pulling, I haven't really tested it.

It's only about "snapshots". Especially against AI who fly in constant loops you may find yourself having him always in the pipper but never above so you can retract flaps for more AoA and lead the guns. It's not much more useful than that.

If you want to have a lot of turnrate you need lift (and engine power). So the more flaps the more turnrate...

You do realise though that more than just LERX do play a role in the rate of speed loss, right? LERX simply give you more control at higher AoA. And they also add a drag at higher AoA. But even that additional drag might simply be not enough to create as much drag as a Mig can, especially when it stalls and then becomes a flying brick with the wings almost perpendicular to the airflow.

Your general understanding of LERX is a tad wrong. They do add drag, they do not remove it as you said. If you had a F-5 without LERX, it would probably lose even less energy as it won't have the additional drag that LERX create.

Your comparsion doesn't make a lot of sense as you compare two completely different aircraft with different designs. If you were to compare an F-5 with and without LERX, that would make a whole lot more sense. 

Stall speed changes, critical AoA does not. You are more interested in the angle at which your aircraft stalls (which is why you have an AoA gauge and indicator), but luckily, this AoA is exceeded at a specific (variable) speed. And stall speed are usually calculated in a such way that you get the highest or the exact stall speed. Stalling at a speed higher than that from the manual is or should only be possible when your wing is contaminated, broken or in any other way changed.

Again, different designs have different properties... Mig has a lower stalling angle to begin with.

The diagram is only a general diagram. If you want to actually know/feel it, you have to test it.

 

From my perspective, I feel you are mixing it up.  Prior to us clarifying that not all the flap options in your diagram are feasibly available for the F-5 during combat or landing, you were implying max AoA would be higher with the flap UP setting.  That is why I ask you what would happen if you are already at max AoA with flaps down, and then retract the flaps at that point.  The point is with UP setting the max AoA is lower, based on the diagram from the manual and your diagram.  So, no, in game retracting the flaps should not allow you to pull more in the F-5.  The combination of extending both the slot and flap together to any degree (I.e autoflaps) still provides more AoA and lift than with both retracted.  So greater pull snapshots with UP flaps is not possible.  And as you concede, more flaps would instead be required for more maneuverability.

 

"But even that additional drag might simply be not enough to create as much drag as a Mig can, especially when it stalls and then becomes a flying brick with the wings almost perpendicular to the airflow."

Yes, that is exactly my point about the LERX.  You both keep focusing on the rate of speed loss as a comparison between more or less AoA on the same LERX enabled plane, while my original comment is with reference to the LERXs preventing the F-5 from comparable speed loss of something like a MiG-21 with no LERX, due to said drag.

And If we are going to be pedantic, the wings of either plane would never be almost perpendicular to the airflow.  Neither plane is capable of pulling a cobra.

No my understanding of LERX is not wrong.  It is your interpretation of my words which is wrong.  I was referring to the comparative speed loss:

"But even that additional drag might simply be not enough to create as much drag as a Mig can, especially when it stalls and then becomes a flying brick with the wings almost perpendicular to the airflow."

You say without LERX there is less speed loss.  Well not if you tried to pull as much G as you could with LERX.  If you did, you would be the flying brick that the 21 would be.

I don't see why I can't compare a 21 as a plane with no LERX to the 5 as plane with LERX.  How else will I illustrate the type of speed lost I was referring to?  I have no pert data on an F-5 with no LERX.  Using the 21 is even better since it performs worse in a turn but has better wing loading.  The lack of comparative turn perf is mainly due to the lack of LERX.

In the end I was originally referring the overall speed loss during combat, while you chose to dissect the comment and drill deep into the technical aspect of something I was not referring to.

[LowRider88]

5 hours ago, Snappy said:

You misunderstood me . I didn't say there are no stall speeds, but that aviation is moving a away from the concept of  a fix stall speed. Because the stall speeds you can find in some aircraft manuals are only ever true under specific conditions (1G, specific aircraft mass,configuration,  center of gravity etc.).So they are very subjective. As soon as conditions change, the speeds are no longer true .

You can stall an aircraft at any speed, yes read that again, any speed  - as long as you can generate sufficient G to reach and exceed critical AOA.

If you fly a cessna 172 or similar you usually dont need to concern yourself with more than 1- 2 G during the entire flight, but even at "only" 2G , stall would already occur at a very different speed than under 1G, which illustrates why the concept of  "fix" stall speeds has limited applicability.

It is useful for calculating safe approach speeds and It has applications in regards to certification of aircrafts, but thats entirely a different matter.

Air combat is seldom performed at 1 G.  

You still don't seem to understand that the Mig in your example does not have a speed loss from stalling. It has a speed loss because its wing generates too much drag if its loaded up too much in a tight turn. 

No I dont mean regaining energy  from a close-to-stall condition, in that situation it would be a bad idea to retract the leading and trailing edge devices as you are already close to critical AOA.

I meant unloading for separation or regaining energy in a fight. Yes, in BFM/ACM.There are uses for it.

Be sceptical as much as you want, but separating from a fight  and/ or regaining energy is a part  of BFM/ACM, as is turning.

Don't have to believe me, check out the Navy CNATRA P-825 / 826  docs on the internet, which are publicly available  . Read the sections about unloaded acceleration and "bug out" which is the navy's term for separting.There are reasons for it.
Alternatively check out the Air Force' s AETC TTP11-1 .

The above mentioned official documents contain BFM/AM theory for both services.

As for how much you gain, by FLAPS UP, well,  for a separation or energy regain you normally want as quick acceleration as possible and me , I wouldn't leave the Flaps and Slats hanging out, producing induced drag which is exactly what you're trying to get rid off in order to maximize acceleration.

Anyway, I'm out at this point. @razo+r seems to have more patience & energy than I do

Regards,

Snappy

 

I don't recall ever referencing stall speeds as fixed.  And even if you are right and the industry is moving away from stall speeds now, this whole thread is about 70s era planes.  The manual refers to stall speeds.

And if we re going to be pedantic, the stall speeds in the manuals are not subjective.  The are contextual.

Of course they change under different conditions.  But under similar or predictable conditions, like any other metric they can be used for relative comparison.  And here, stalls speeds are available in manuals.

 

"You can stall an aircraft at any speed, yes read that again, any speed  - as long as you can generate sufficient G to reach and exceed critical AOA."

I don't need to read that twice or even once.  I was already aware of that from the manual diagram I cited, remember?

By any speed, are you implying the F-5 can be stalled at 1.6 M?  Wow, then why build an Su-27 when the Soviets could have just copied the F-5.  Most likely if you tried to pull enough G here, the wings would break off, or the plane would through inertia continue its course until the attempt to pull Gs lowered the plane down to the manual' defined stall speed.

 

"Air combat is seldom performed at 1 G.  "

No where did I imply this, "fixed", or cessnas.  Not sure why you pulled this out of thin air.

I think you are confusing relative with fixed.

 

"You still don't seem to understand that the Mig in your example does not have a speed loss from stalling. It has a speed loss because its wing generates too much drag if its loaded up too much in a tight turn. "

I don't think you understand that the stall is the extreme case of the condition you described.  Whether just a tight turn, or a full on stall, that same speed loss, whether at or approaching the limit, in comparison with the F-5 with LERXs, with both turning the same g, the 21 has greater speed loss.  So in comparison with a plane with no LERX, the F-5 has less speed loss.  My original point.

 

"Be sceptical as much as you want, but separating from a fight  and/ or regaining energy is a part  of BFM/ACM, as is turning."

When was I skeptical of separation or energy management being outside of BFM/ACM?  A more careful reading would show you I said chasing someone is hardly BFM/ACM.  Chasing is not the same as the techniques in an Energy Fight.  I will check out the doc you cited, Thanks for that.  But not for the reason you specified, because you misunderstood me.

 

"As for how much you gain, by FLAPS UP, well,  for a separation or energy regain you normally want as quick acceleration as possible and me , I wouldn't leave the Flaps and Slats hanging out, producing induced drag which is exactly what you're trying to get rid off in order to maximize acceleration."

Yes, but do you have verifiable evidence that you accelerate noticeably faster with enough utility, when compared to just unloading while in AUTO, I.e what ever gain you state is not a theoretical subjective feeling and is in fact better than the optimized optimization designed by the engineers for AUTO.  If you have proof, I would Lear the technique.  But until then, I see no loss in effectiveness from flying with AUTO on during all turn or energy fighting.

 

i agree.  This whole off topic tangent is exhausting, and detracted from the fun of the experiment I was proposing.

[LowRider88]

Not that anyone may care at this point , but I did extend my mini experiment mentioned above.

Beyond timing myself for how long it took for me to defeat the Trained AI 21 with a 5, I setup a purely AI battle where both planes were Trained.  In this case the battle lasted way longer than the 4 minutes of the article.  I had to leave the 21 at Trained and set the 5's AI to Ace to achieve the same under 4 min time I got, and the article had.

Based on this I believe the F-5 AI FM is not optimized.  I raised a bug report over a year ago believing the F-5 AI does not utilize its flaps, and I think this experiment illustrates this.