Regarding physics of a plane....

[303_Kermit]

Hello

 

I spoke today with one of my colleagues, who tried to convince me to buy JF17. Well... I don't know it so I asked "can you show me how does it fly?" Well (he said) it is quite cool, MiG29 engine, nice western avionics. Nice plane; I'll show you:

 

He took 4 rockets (2xSD10 and 2xPL5). Than he made an air-start at a altitude 3000ft. According TAC View:

Afterburner - left hand horizontal turn, Stick pulled full and....

 

0,85Ma/ AOA 6,5°/ 8,1G/ and plane ... accelerates :pilotfly:

 

at about 8,7Ma fly by wire reduces G load to 6G and plane still accelerates :joystick:

.... insane.:cry:

 

::::::

 

 

We just tested F16, F18 they all have the same idiotc characteristics.... F16 is really extreme... Accelerates insane by 9G load

 

With my best regards

Kermit

 

PS... Can someone move the post to Topic "Flight model" or something more appropriate?

Edited July 24, 2020 by 303_Kermit

[probad]

yeah welcome to modern jet engines

 

aim-9x pulls 40g's and still accelerates on motor so tell me what kind of physics are you implying should work here

Edited July 24, 2020 by probad

[AeriaGloria]

Hello

 

I spoke today with one of my colleagues, who tried to convince me to buy JF17. Well... I don't know it so I asked "can you show me how does it fly?" Well (he said) it is quite cool, MiG29 engine, nice western avionics. Nice plane; I'll show you:

 

He took 4 rockets (2xSD10 and 2xPL5). Than he made an air-start at a altitude 3000ft. According TAC View:

Afterburner - left hand horizontal turn, Stick pulled full and....

 

0,85Ma/ AOA 6,5°/ 8,1G/ and plane ... accelerates :pilotfly:

 

at about 8,7Ma fly by wire reduces G load to 6G and plane still accelerates :joystick:

.... insane.:cry:

 

::::::

 

 

We just tested F16, F18 they all have the same idiotc characteristics.... F16 is really extreme... Accelerates insane by 9G load

 

With my best regards

Kermit

 

PS... Can someone move the post to Topic "Flight model" or something more appropriate?

 

That’s the point of F-16:)

 

For JF-17 and pretty much any of these planes, it’s important to remember that G load is one of many factors, and what is likely the true cause off this behavior is the natural occurrence of AOA needed per G decreasing as you go faster. Since if your faster you need less AOA to pull same G, that means less drag, and greater SEP(specific excess power) or the power curve, usually as a chart you will see excess power increase and increase then go down as pulling G near max speed is unsustainable. So once the G limiter is limited to 6Gs, it now has way more power then it needs to hold that G and speed and with pulling less G there’s less drag. And that actually one of its biggest dangers, you need to carefully manage speed becuase it’s easy to get caught over Mach .87 and only be able to do 6G where you can’t slow down as fast and leaving it in afterburner is only going to make you go faster. I’m still waiting for someone to use this against me in a dogfight....

 

It also helps contribute to this effect that jet engines increase power as speed becomes high subsonic, so the engines themselves are helping also as speed increases up to a point

 

All in all with its strakes, oddly cambered rear wing extension, instability, despite having smaller G load then F-16 it can sustain a very similar turn rate at low altitudes and slower speeds. It is optimized for low to mid altitudes(however you do have lower wing loading then F-16, and when clean have a 4,000 ft higher ceiling), so at the 3000 ft you mention it really can be a monster until it runs out of fuel

 

Is your personal point of comparison Hornet?

Edited July 24, 2020 by AeriaGloria

[303_Kermit]

That’s the point of F-16:)

 

For JF-17 and pretty much any of these planes, it’s important to remember that G load is one of many factors, and what is likely the true cause off this behavior is the natural occurrence of AOA needed per G decreasing as you go faster. Since if your faster you need less AOA to pull same G, that means less drag, and greater SEP(specific excess power) or the power curve, usually as a chart you will see excess power increase and increase then go down as pulling G near max speed is unsustainable. So once the G limiter is limited to 6Gs, it now has way more power then it needs to hold that G and speed and with pulling less G there’s less drag. And that actually one of its biggest dangers, you need to carefully manage speed becuase it’s easy to get caught over Mach .87 and only be able to do 6G where you can’t slow down as fast and leaving it in afterburner is only going to make you go faster. I’m still waiting for someone to use this against me in a dogfight....

 

It also helps contribute to this effect that jet engines increase power as speed becomes high subsonic, so the engines themselves are helping also as speed increases up to a point

 

All in all with its strakes, oddly cambered rear wing extension, instability, despite having smaller G load then F-16 it can sustain a very similar turn rate at low altitudes and slower speeds. It is optimized for low to mid altitudes(however you do have lower wing loading then F-16, and when clean have a 4,000 ft higher ceiling), so at the 3000 ft you mention it really can be a monster until it runs out of fuel

 

Is your personal point of comparison Hornet?

 

Before you start explaining me how plane flies. I am master engineer Machine building, specialty planes.

 

Make simple multiplicaton: 9x a Waight of F16. and think ... how long F 16 can fly with such a load. Could it maintain speed and 5-7° AOA? I don't have time and nobody pays me for a Aerodynamic prelection, just make a simple calculation. 9G = 9x 9000kg = 81000kg (178574pdr). How long aerodynamic of F 16 can hold such load? How much thrust do you need to maintain 0,9Ma under such load? What AOA do you need to hold 81000 kg in air by 0.9Ma at 3000ft?. Think...

 

I am not writing about air density by subsonic speed (it produces additional drag) , or other factors, and there's a lot of them.

 

I red somewhere here that I payed for high quality product. I want to see quality

Edited July 24, 2020 by 303_Kermit

[AeriaGloria]

Before you start explaining me how plane flies. I am master engineer Machine building, specialty planes.

 

Make simple multiplicaton: 9x a Waight of F16. and think ... how long F 16 can fly with such a load. Could it maintain speed and 5-7° AOA? I don't have time and nobody pays me for a Aerodynamic prelection, just make a simple calculation. 9G = 9x 9000kg = 81000kg (178574pdr). How long aerodynamic of F 16 can hold such load? How much thrust do you need to maintain 0,9Ma under such load? What AOA do you need to hold 81000 kg in air by 0.9Ma at 3000ft?. Think...

 

I am not writing about air density by subsonic speed (it produces additional drag) , or other factors, and there's a lot of them.

 

I red somewhere here that I payed for high quality product. I want to see quality

 

Well the F-16 forum can probably answer that best, and also take a look at the charts posted in the Flight Modeling PDF that was in the newsletter. It’s reported by many sources that F-16 has a corner plateau where at a range of speeds while clean at low altitude it can sustain 9G. This is what it was built for. So it must be able to do that within is AOA limit, and I have no reason to not believe the multitude of official sources about F-16s having a 9G corner plateau.

[Terrorban]

Before you start explaining me how plane flies. I am master engineer Machine building, specialty planes.

 

Make simple multiplicaton: 9x a Waight of F16. and think ... how long F 16 can fly with such a load. Could it maintain speed and 5-7° AOA? I don't have time and nobody pays me for a Aerodynamic prelection, just make a simple calculation. 9G = 9x 9000kg = 81000kg (178574pdr). How long aerodynamic of F 16 can hold such load? How much thrust do you need to maintain 0,9Ma under such load? What AOA do you need to hold 81000 kg in air by 0.9Ma at 3000ft?. Think...

 

I am not writing about air density by subsonic speed (it produces additional drag) , or other factors, and there's a lot of them.

 

I red somewhere here that I payed for high quality product. I want to see quality

 

For starters, you are not a master of anything. Second, if you have time to ask in forum about something complex, give us a valid and equal explanation.

 

These jets are not designed with your elementry school equations. Just like your claim that there are many factors which cause drag, there are just as many solutions designed to reduce or nullify its effects.

 

If you don't have time to even explain in detail why you believe it is not realistic, how did you expect someone else to spend time and do research on your behalf? Maybe if developers have time, they might answer your question however, you did not present any detailed evidence of your claimed master machine builder status.

 

If you wish to discuss this topic, present your case in more detail. This community does contain some very knowledgeable people.

[dorianR666]

9G = 9x 9000kg = 81000kg (178574pdr). How long aerodynamic of F 16 can hold such load? How much thrust do you need to maintain 0,9Ma under such load? What AOA do you need to hold 81000 kg in air by 0.9Ma at 3000ft?.

:huh:

n̶o̶w̶ ̶i̶ ̶m̶a̶y̶ ̶n̶o̶t̶ ̶b̶e̶ ̶a̶n̶ ̶e̶n̶g̶i̶n̶e̶e̶r̶ ̶b̶u̶t̶ ̶t̶h̶e̶ ̶G̶s̶ ̶i̶s̶ ̶a̶ ̶f̶o̶r̶c̶e̶ ̶p̶u̶s̶h̶i̶n̶g̶ ̶i̶n̶t̶o̶ ̶t̶h̶e̶ ̶"̶f̶l̶o̶o̶r̶"̶,̶ ̶p̶e̶r̶p̶e̶n̶d̶i̶c̶u̶l̶a̶r̶l̶y̶ ̶t̶o̶ ̶t̶h̶e̶ ̶v̶e̶c̶t̶o̶r̶ ̶o̶f̶ ̶f̶l̶i̶g̶h̶t̶,̶ ̶i̶t̶s̶ ̶n̶o̶t̶ ̶p̶u̶s̶h̶i̶n̶g̶ ̶a̶g̶a̶i̶n̶s̶t̶ ̶t̶h̶e̶ ̶e̶n̶g̶i̶n̶e̶s̶.̶ ̶f̶l̶y̶i̶n̶g̶ ̶a̶t̶ ̶9̶G̶ ̶d̶o̶e̶s̶n̶t̶ ̶m̶a̶k̶e̶ ̶t̶h̶e̶ ̶p̶l̶a̶n̶e̶ ̶9̶x̶ ̶h̶e̶a̶v̶i̶e̶r̶ ̶a̶n̶d̶ ̶n̶e̶e̶d̶i̶n̶g̶ ̶9̶x̶ ̶t̶h̶e̶ ̶t̶h̶r̶u̶s̶t̶.̶.̶.̶

i read thrust instead of AOA, my bad

Edited July 25, 2020 by dorianR666

[303_Kermit]

For starters, you are not a master of anything. Second, if you have time to ask in forum about something complex, give us a valid and equal explanation.

 

These jets are not designed with your elementry school equations. Just like your claim that there are many factors which cause drag, there are just as many solutions designed to reduce or nullify its effects.

 

If you don't have time to even explain in detail why you believe it is not realistic, how did you expect someone else to spend time and do research on your behalf? Maybe if developers have time, they might answer your question however, you did not present any detailed evidence of your claimed master machine builder status.

 

If you wish to discuss this topic, present your case in more detail. This community does contain some very knowledgeable people.

 

I can write here about complexity of Navier-Stockes equation, or about a fact that most of aerodynamics equations used for computer airflow-simulations are non physical. I can talk an hour about Aeroelasticity, or phugoid oscilation(s). It will be just a waste of time since 99%of you won't understand anything what I am saying about.

 

I try to speak as simple as it's necessary so somebody like guy above can understand...

 

I posted nicely that there is a major error in a game. And it is not a matter of discussion for me. I invested enough of my time ( i think). I am not used to do it unpayed. I can make any caclulations you need or want. As well as Aerodynamical analyse in Fluent, or NX.

 

... That is of course if you pay.

 

 

With my best regards

Kermit

Edited July 25, 2020 by 303_Kermit

[LJQCN101]

I'm talking about real life right now.

 

For JF-17 it's able to sustain 8G at Sea Level 0.66 Mach with 2 x PL-5 and 50% fuel at Max AB, Standard Day. Above that speed your Specific Excess Power is greater than 0 even at 8G so your plane would accelerate. Those are in the EM Charts from flight manual.

 

For F-16 it would be more prominent. It can sustain 9G (SEP = 0) at Sea Level 0.81 Mach with Drag Index = 50 equivalent of stores and gross weight of 26,000 lbs. For the trend of the SEP=0 curve it can even sustain 10G if there were no G-limit. Those are also in the EM Charts from flight manual.

 

Well, just saying you can report this to the F-16 bug forum too.

Edited July 25, 2020 by LJQCN101

[Shadowless]

If you finish your high school course, you should know why a plane can accelerate while maintain high gravity load.

And there is no need to mention CFD software in this discussion because your problem is about flight dynamics, but CFD software is for aerodynamics. You should know the differences if you are in aerospace industry.

[Rick50]

The F-16 has been in service for 41 years now... if it couldn't actually perform like a sky monster that the manufacturer claimed all those years ago, I think it would have been noticed by now!

 

And yet, it still is in production, still being bought brand new, still being improved, still chosen by many airforces with high requirements. If that's still implausible, I wonder what he'll think when a Typhoon or Raptor shows up?

[Blinky.ben]

The F-16 has been in service for 41 years now... if it couldn't actually perform like a sky monster that the manufacturer claimed all those years ago, I think it would have been noticed by now!

 

And yet, it still is in production, still being bought brand new, still being improved, still chosen by many airforces with high requirements. If that's still implausible, I wonder what he'll think when a Typhoon or Raptor shows up?

 

By they way this person is talking it sounds like he personally made the Raptor

[dundun92]

By they way this person is talking it sounds like he personally made the Raptor

:megalol:

[TaxDollarsAtWork]

I'm talking about real life right now.

 

For JF-17 it's able to sustain 8G at Sea Level 0.66 Mach with 2 x PL-5 and 50% fuel at Max AB, Standard Day. Above that speed your Specific Excess Power is greater than 0 even at 8G so your plane would accelerate. Those are in the EM Charts from flight manual.

 

For F-16 it would be more prominent. It can sustain 9G (SEP = 0) at Sea Level 0.81 Mach with Drag Index = 50 equivalent of stores and gross weight of 26,000 lbs. For the trend of the SEP=0 curve it can even sustain 10G if there were no G-limit. Those are also in the EM Charts from flight manual.

 

Well, just saying you can report this to the F-16 bug forum too.

Could you post these charts here? Are the JF17 ones included in the manual?

[AeriaGloria]

Could you post these charts here? Are the JF17 ones included in the manual?

 

The real manual:D

[Hummingbird]

8 G's @ 0.66 M is very impressive.

 

That said the only thing really letting the JF-17 down is the thrust to weight ratio of 0.95, meanwhile its wing loading is surprisingly low (Chinese really made the aircraft very light, probably at the cost of structural strength, hence the 8 G limit) and it makes use of both large LERX as well as ofcourse LE & TE maneuver devices.

[Gierasimov]

So, in this recent interview, that was said:

 

"(...) We are aware that the Jeff, JF-17, - many people feel that it overperforms reality and we are in ongoing discussion and review(...)"

 

Source:

 

I am just happy, that ED is taking it seriously and actually interested in quality of 3rd party products, irrespective of the outcome of this review.

[sylkhan]

..I am just happy, that ED is taking it seriously and actually interested in quality of 3rd party products, irrespective of the outcome of this review.

 

It's strange, it's seems that ED is specifically focus in quality of one third party "DEKA", what about the others...?

 

And DEKA is by far, the best and the more professionnal third party who deliver the best quality of products, strange, isn't it ?

 

They have a lot of work with the others RAZBAM, HEATBLUR, POLYSHOP with their Gazelle, ahaha...but ...nio words

 

And no, unfortinately ED don't care about quality of products of third parties, they only care about theirs sells and a part of theirs customers.

[Blinky.ben]

So, in this recent interview, that was said:

 

"(...) We are aware that the Jeff, JF-17, - many people feel that it overperforms reality and we are in ongoing discussion and review(...)"

 

Source:

 

I am just happy, that ED is taking it seriously and actually interested in quality of 3rd party products, irrespective of the outcome of this review.

 

Wonder if you would share the same opinion if it was American origin aircraft? Highly doubt it.

Edited August 8, 2020 by Blinky.ben

[EnvyC]

Wonder if you would share the same opinion if it was American origin aircraft? Highly doubt it.

 

 

You know they wouldn't.

[J20Stronk]

Wonder if you would share the same opinion if it was American origin aircraft? Highly doubt it.

 

Considering no one is up in arms about the F-16's radar being able to detect small fighter-sized targets in TWS 80+nm away, no he isn't.

[303_Kermit]

For all those who keep saying that plane maintaining 9G turn MUST maintain constant airspeed (or accelerate) i'd like to remember, that ... It isn't. To maintain 9G turn your airplane needs to maintain constant turn ratio. Airspeed may raise (than turn radius raise also), or drop (radius drops). It's actually more kinematic (or flight mechanic) than aerodynamic. Quite basic thing. Reasonable explanation you may find for example in

-Roskam "Airplane aerodynamics and performance"

for those who thinks about aerodynamics seriousely and poseses necessary mathematic skills i recommend

-Arzanikow / Malcew "Aerodynamics"

 

With my best regards

Kermit

Edited August 16, 2020 by 303_Kermit

[LJQCN101]

For all those who keep saying that plane maintaining 9G turn MUST maintain constant airspeed (or accelerate) i'd like to remember, that ... It isn't. To maintain 9G turn your airplane needs to maintain constant turn ratio. Airspeed may raise (than turn radius raise also), or drop (radius drops). It's actually more kinematic (or flight mechanic) than aerodynamic. Quite basic thing. Reasonable explanation you may find for example in

-Roskam "Airplane aerodynamics and performance"

for those who thinks about aerodynamics seriousely and poseses necessary mathematic skills i recommend

-Arzanikow / Malcew "Aerodynamics"

 

With my best regards

Kermit

 

Ps = (v/g)*(dv/dt) + dh/dt.

 

In RL Flight Manuals it is very specific that you find your sustained turn rate at Ps=0 curve, which means your airspeed AND altitude may not change when performing such a turn.

 

You may find turn rate chart with Ps curve in T.O.1F-16CM-1-1, and explanations of sustained turn rate in AFTTP (Air Force Tactics, Techniques and Procedures) 3-3 Vol.5

 

Sustained rate. The rate an aircraft can generate while maintaining airspeed and altitude (Zero Ps).

Edited August 17, 2020 by LJQCN101

[dundun92]

Considering no one is up in arms about the F-16's radar being able to detect small fighter-sized targets in TWS 80+nm away, no he isn't.

I take it you didnt see this thread? ;)

 

https://forums.eagle.ru/showthread.php?t=280422

Edited August 18, 2020 by dundun92

[lunaticfringe]

I'm talking about real life right now.

 

For JF-17 it's able to sustain 8G at Sea Level 0.66 Mach with 2 x PL-5 and 50% fuel at Max AB, Standard Day. Above that speed your Specific Excess Power is greater than 0 even at 8G so your plane would accelerate. Those are in the EM Charts from flight manual.

 

Reupping the request from others. Many moons ago, in a thread that appears to have been subsequently deleted, it was stated that Deka's intent was to make these sorts of materials available to assist in validation.

 

Fulfilling on that intention might go a long way to help cut these sorts of threads, and other challenges of the JF-17s pedigree, off at the pass.

 

Any movement on this as such would be appreciated.