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Subject: Dogfight tricks ...
Bluewings12    4/22/2009 6:07:56 PM
A M2000-5 Pilot here in Dijon ~a friend of mine~ told me that He and his aircraft can leave any other following aircraft in the dust with one pass . When I asked "any aircraft ?" , he said yes and he directed me to that video : h*tp://www.dailymotion.com/video/x3424v_french-air-force-mirage-20005_shortfilms He said to me , check from 1:12 to 1:28 . He explained to me that the Mirage is diving instantly nose first with a negative 4Gs plunge , followed by a 6g plate then followed by an 11g 180deg turn , the end speed is close to 300 knots . He said to me , "imagine where the bugger who is following you ends up ? NOWHERE !" To start with , 99% of the Pilots will not plunge nose first but will make a roll to dive "against the Gs" . There are 3 reasons to do so : #1 to avoid the "red-out" , # the FBW is not at ease , #3 you need a delta wing . When I asked him how he could turn the situation to his advantage , his answer was simple : "keep turning high Gs left or right , depends where he went and you 'll end up behind him , if he goes vertical go vertical too , he will ALSO be in front of you" Please , post some other nice videos of good dogfight tricks :-) Cheers .
 
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PierreLeGrand       5/12/2009 6:36:00 AM




I have done no finite element analisys on any of the planes mentioned, so there's no way of knowing, really.



Why is everybody so intent on putting data here for which there is no means of verification and being so c%cksure about it? Why should I believe such stuff on the basis of "Some guy on the internet said so"?



You choose what you want to believe, who you want to trust. The main necessity here is that no one lacks respect toward others.

Claiming absolute negative BS against Rafale because BW and FS have been boring with very positive opinions about Rafale is stupid too.

Insulting the others because "they are wrong while i'm right" is stupid too.

 You're free to choose.

Another thing i may want you to believe, since i trust the guy who told me this for obvious reasons :

Dassault has been working a 90hPa "Combat-Edge"-like equipment to make Rafale pilots capable of sustaining 11G so as to increase their survivability in case of emergency as well as for combat. This equipement finally was not adopted because it was not confortable (temperature).

The true software limit on Rafale is... 8G (Gs and G-onset are limited to protect the backseater). Once you pull stronger on the stick, you're free up to 11G, but pilots  usually do not exceed 9G, which is usually enough, and already extremely demanding.

 The BW claims about 10 to 11G in demonstration surprise me, but i can't deny them.
Claiming that new gen aircraft will fail above 9G is stupid, or just jealousy. Why would the Libelle G-suit could help a pilot in sustaining 12G if the aircraft can't do it ?



+1.
 
This goes some major way to prove that you know your aircraft that little and it's all credit to you, you see i just forgot this little "detail" myself and yet just read the early test flyight report for the tenth time, to my credit i was more into structural loads than the real FCS soft limitations...
 
Regards. PlG
 
 
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warpig       5/12/2009 8:06:17 AM

G onset like any other g datas is measured by m/sec2 = g.

 

At Edward AFB its is computed using the following datas:

 

2.300 ft geometric altitude and 32.136 ft/sec2 g value.

 

As everyone writing on the subject should know, gravity varies with altitude but also geographic location with noticeable variations ranging from, 0.26 to - 0.27.

 

  As i have spent some time at BA-102 myself, knows its location (as well as that of the video meeting and aircraft type bases, btw not Dijon-based 5F but 2000DA) I can certify that local g values are within these parameters.

 

  Much the same way, i can safely assume that Maximum load values are perfectly valid in this particular case...

 

  The amount of g pulled here is below the level requiered to cause structural damages to the airframe by at least two units.

 

Regards, PlG



 
What are you mumbling about?  What is it with BW and apparently you, too, that you two appear driven to try to have some sort of googled-up response to every post, like you are trying to demonstrate you "knew that all along" or something.  By the way, that's an interesting point about how the force of gravity varies over the Earth's surface.  I had forgotten about that fact, but you're absolutely right that it does change slightly.  But if your comment meant that gravitational force experienced here on Earth's surface varies in the range 0.73G to 1.26G, I say that's way off, and I'd bet the fluctuation is more like 0.999G to 1.001G at most.  In any event, it has nothing to do with what I was talking about.
 
G onset rate is the rate at which you change your load factor, i.e., Gs.  For example, yanking the stick back into your lap and piling on 6Gs very quickly, like within a couple tenths of a second, can easily be more likely to cause GLOC than pulling the stick back over the course of a couple seconds and slowly building up to 8Gs.
 
 
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PierreLeGrand    @warpig    5/12/2009 9:12:45 AM
What are you mumbling about?
 
What you obviously dont know coming up with such things as "G onset" which btw is properly spelt as g onset and got your estimates on the changes in hearth gravity widely under what they really are...
 


But if your comment meant that gravitational force experienced here on Earth's surface varies in the range 0.73G to 1.26G,
 
 
 

 
These are the values used at the USAF flight Testing Center of Edward AFB and the French EPNER, if you know better than they do please apply for the position of director of flight testing Ops they'll send you a checque immediatly for travel expenses.
 
  Next:
 
 You could do with computing the variables due to your testing altitude, Heading and Speed at normal load factor.
 
  Then only could you have a proper idea of what your g onset value is.
 
 
 
 In any event, it has nothing to do with what I was talking about.
 
It has everything to do with what you where talking about being the proper way to calculate any g datas including onsets.
 
 
 
G onset rate is the rate at which you change your load factor, i.e., Gs.
 
You insist in spelling it wrongly and trying to lecture people who are well aware of what g onset is as well as knowing what you don't know about gs...
 
So please try again: How to compute g onset: m/sec2 = g.
 
And if you whant to be very precise about it you WILL use the local geometric altitude, g values, heading, speed  because it variates enough from one geolocation to the other as  to make such a difference at every levels (including design) that lifes can be put at risk.
 
Aeronautic is as much as possible a precise science and next chaper is about effect of heading on drag coefficient.
 
So please do not serve me g onsets as my little resume m/sec2 = g. (very much simplified i'm afraid) is all you need to do to compute it at your level.
 
  Source is:
 
Technical Information Handbook.
 
Air Force Flight Test Center, Edward Air Force Base Edition 2000 updated 2003. 
 
I think it is available for public use these days.
 
Regards, PlG
 
 
 
 
 
 
 
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StevoJH       5/12/2009 9:16:35 AM




G onset like any other g datas is measured by m/sec2 = g.



 



At Edward AFB its is computed using the following datas:



 



2.300 ft geometric altitude and 32.136 ft/sec2 g value.



 



As everyone writing on the subject should know, gravity varies with altitude but also geographic location with noticeable variations ranging from, 0.26 to - 0.27.



 



  As i have spent some time at BA-102 myself, knows its location (as well as that of the video meeting and aircraft type bases, btw not Dijon-based 5F but 2000DA) I can certify that local g values are within these parameters.



 



  Much the same way, i can safely assume that Maximum load values are perfectly valid in this particular case...



 



  The amount of g pulled here is below the level requiered to cause structural damages to the airframe by at least two units.



 



Regards, PlG








 

What are you mumbling about?  What is it with BW and apparently you, too, that you two appear driven to try to have some sort of googled-up response to every post, like you are trying to demonstrate you "knew that all along" or something.  By the way, that's an interesting point about how the force of gravity varies over the Earth's surface.  I had forgotten about that fact, but you're absolutely right that it does change slightly.  But if your comment meant that gravitational force experienced here on Earth's surface varies in the range 0.73G to 1.26G, I say that's way off, and I'd bet the fluctuation is more like 0.999G to 1.001G at most.  In any event, it has nothing to do with what I was talking about.

 

G onset rate is the rate at which you change your load factor, i.e., Gs.  For example, yanking the stick back into your lap and piling on 6Gs very quickly, like within a couple tenths of a second, can easily be more likely to cause GLOC than pulling the stick back over the course of a couple seconds and slowly building up to 8Gs.

 

Can't we just say that 1G = 9.8m/sec^2 and be done with it? The variation would be miniscule anyway.
 
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PierreLeGrand    StevoJH    5/12/2009 9:38:42 AM
You are right!
 
 My quote on known location was VERY sarcastic; meaning it "happened on hearth".
 
I know what our aircrafts Max Load Factor are since Mirage III and FCS soft/hard limits since Mirage 2000 and I can tell you that to world's standards they are built like bricks.
 
High g doesn't only occur in a controled way sometimes aircraft goes out of control and values of up to 30 g have been recorded in many occasion, in all axis with different result depending on the axis, altitude and of course aircraft.
 
The best example i can give to you is the USN A4 Skyhawk which leading edge slats could open independently, sometime creating a roll movement with a g onset (recorded) of 30 g, one guys was lucky enough to recover from the black out and brought it RTB with most rivets poped out from the wings, i am not sure it flew again though...
 
 So it came to no surprise to me that some jockey could pull 11 g in an instantaneous turn and go away with it when he signed off the aircraft to the techies.
 
This would be the main problem with AdA, there are stress "witnesses" if i can say so, if an aircraft goes above the limit the ground crew will know it at the post-flight visit, whatever the pilot does about it, even without looking at the flight recorder, and they don't like when their machines come back home all bent.
 
What i was demonstrating there was that  the g values of 11 were totaly possible physicaly and operationaly since we are looking at 11 g vs a Maximum Load Factor 1.9, I don't see where the problem would be with the aircraft structural fatigue.
 
Regards, PlG
 
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FJV    Looked at the data   5/12/2009 3:51:18 PM
The data you cited actually disproves what you are saying. Source:
 
"http://www.dassault-aviation.com/fileadmin/user_upload/redacteur/AUTRES_DOCS/Fox_three/FoxThree_N9.pdf"

The engineers? attention then switched to the static trials during which the Rafale was tested up to 185 percent of design limit load before the airframe broke.
 
There are actually 2 material properties being confused here:
-1 The yield strength of a material.
    The stress at which a material begins to deform plastically. That is the stress at which the deformation of a
    material will be permanent.
-2 The breaking strength of a material.
    The stress at which a material breaks, which is much higher than the yield strength.
 
When I (and  pretty much every one I know) make a design calculation for strength we use the yield strength with the required safety factor as the stress limit that must not be exceeded. I'm willing to believe that for planes they make an additional calculation for breaking stress. However these are 2 different things.
 
The text quoted talks about breaking strength at 185%. Problem is the airframe failed long before that, because the airframe failed when the material stresses passed the yield point. After the stresses passed the yield point the airframe would be permanently deformed (bent out of shape) and would have to be thrown away or at the very least would need a major structural overhaul.
 
Should fly by wire software allow a pilot make an extreme maneuver that wrecks the aircraft for further use to save his skin? I guess so. Does this mean that we can claim such plane can make 15G turns? Not really, it can only make that turn once.
 
I cannot see why everybody gets so up in arms when someone claims one parameter of another airplane is better than the F35 or F22. I really don't see the huge issues here or the reason for all the emotion. Ever since the HIMAT research in the 80's we reasonably can assume the US is easily able to make planes that can make sustained 12G turns (as achieved in HIMAT research). The reason the US plane designers voluntarily choose to limit the maneuverability of the F22 and F35 to much less indicates to me that the ability to make high G turns is only useful up to a point.
 
PS
Herald you claim knowing the subject and then you miss something so obvious as the difference between yield strength and breaking strength. Tsk, tsk.
 
I'm not mad, but I must admit I am somewhat disappointed.
 
 
 
 
 
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warpig       5/12/2009 4:02:43 PM

What are you mumbling about?

 

What you obviously dont know coming up with such things as "G onset" which btw is properly spelt as g onset and got your estimates on the changes in hearth gravity widely under what they really are...

 





But if your comment meant that gravitational force experienced here on Earth's surface varies in the range 0.73G to 1.26G,

 

 

 




 

These are the values used at the USAF flight Testing Center of Edward AFB and the French EPNER, if you know better than they do please apply for the position of director of flight testing Ops they'll send you a checque immediatly for travel expenses.

 

  Next:

 

 You could do with computing the variables due to your testing altitude, Heading and Speed at normal load factor.

 

  Then only could you have a proper idea of what your g onset value is.

 

 

 

 In any event, it has nothing to do with what I was talking about.

 

It has everything to do with what you where talking about being the proper way to calculate any g datas including onsets.

 

 

 

G onset rate is the rate at which you change your load factor, i.e., Gs.
 

You insist in spelling it wrongly and trying to lecture people who are well aware of what g onset is as well as knowing what you don't know about gs...

 

So please try again: How to compute g onset: m/sec2 = g.

 

And if you whant to be very precise about it you WILL use the local geometric altitude, g values, heading, speed  because it variates enough from one geolocation to the other as  to make such a difference at every levels (including design) that lifes can be put at risk.

 

Aeronautic is as much as possible a precise science and next chaper is about effect of heading on drag coefficient.

 

So please do not serve me g onsets as my little resume m/sec2 = g. (very much simplified i'm afraid) is all you need to do to compute it at your level.

 

  Source is:

 

Technical Information Handbook.

 

Air Force Flight Test Center, Edward Air Force Base Edition 2000 updated 2003. 

 

I think it is available for public use these days.

 

Regards, PlG

 

 


 

 

 

 



 
Okay, look, you big peter, I was cutting you some slack but you had to go and be a jerk about it.  First of all, brainiac, those gravitational variations of "+0.26 to -0.27" are expressed as a PERCENTAGE of the nominal value of 9.8m/s2, or 1G.  In other words, they vary up and down from 9.8m/s2 by at most +0.26% and -0.27%.  Gosh, let's see, that would mean they vary from 0.9973G to 1.0026G.  Golly, my complete guess based on little more than common sense was off by about 0.001Gs!  Secondly, yes, I understand that since the units of gravity are not called by a proper name, like Ohms or Watts, then technically the letter designation doesn't need to be capitalized.  However, I like using "G" instead of "g" because I think it is less ambig
 
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gf0012-aust       5/12/2009 4:44:22 PM
This would be the main problem with AdA, there are stress "witnesses" if i can say so, if an aircraft goes above the limit the ground crew will know it at the post-flight visit, whatever the pilot does about it, even without looking at the flight recorder, and they don't like when their machines come back home all bent.

how can the pilot not know he's passed the limit when modern aircraft are fitted with frame stress alerts.  it's audible and it's repeared until the aircraft leaves that condition. if the ground crew check the logs and discover post FSR alerts, then the pilot is certainly going to know.

its designed to alert the pilot to keep the aircraft within safety margins - it's not an indication of a planes limits at early onset. The issue is sustained g manouvre above the FSR, at some point, if not backed off the aircraft can structurally go catastrophic.  the reason why it may go catastrophic without apparent warning is that the frame has a degree of elasticity.  beyond and under sustained onset, instead of "bending" the frame it will fracture.  now I'm not sure what the AdA does, but if an aircraft triggers the FSR, then it is going to go in for an xray or structural analysis just to check whether microfissures have developed post elasticity.

I'd argue that using Red Bull aircraft as a comparison is hardly accurate as the aircraft are designed for continual high g stressing, eg the aircraft centre of gravity loads for jet fighters are completely different).  In fact IIRC one of the americans in here is a competition flyer and can pass his own comment. 
 
 
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PierreLeGrand       5/12/2009 5:25:03 PM

how can the pilot not know he's passed the limit when modern aircraft are fitted with frame stress alerts.  it's audible and it's repeared until the aircraft leaves that condition. if the ground crew check the logs and discover post FSR alerts, then the pilot is certainly going to know.



its designed to alert the pilot to keep the aircraft within safety margins - it's not an indication of a planes limits at early onset. The issue is sustained g manouvre above the FSR, at some point, if not backed off the aircraft can structurally go catastrophic.  the reason why it may go catastrophic without apparent warning is that the frame has a degree of elasticity.  beyond and under sustained onset, instead of "bending" the frame it will fracture.  now I'm not sure what the AdA does, but if an aircraft triggers the FSR, then it is going to go in for an xray or structural analysis just to check whether microfissures have developed post elasticity.

I'd argue that using Red Bull aircraft as a comparison is hardly accurate as the aircraft are designed for continual high g stressing, eg the aircraft centre of gravity loads for jet fighters are completely different).  In fact IIRC one of the americans in here is a competition flyer and can pass his own comment. 
 
 

Considering the conditions it is not unthinkable that one can obviously not have noticed he pulled 11.5 g rather that 11.

  I'll pass the lecture on maximum structural g loads, you guys still miss the point big time...

 

I'd argue that using Red Bull aircraft as a comparison is hardly accurate as the aircraft are designed for continual high g stressing,

 

  Well this must be the quote of the year.

  Manufacturers the world over are fighting about Max sustained turn rates and you vcame up over here telling us that they do not design the most agile dogfighter to sustain these?

  Allow me to laugh, as for RebBull aircrafts some of the pilot pulling 11g publicly, your guys notions on the margins is to say the least lacking.

 
FJV

I cannot see why everybody gets so up in arms when someone claims one parameter of another airplane is better than the F35 or F22. I really don't see the huge issues here or the reason for all the emotion.


 You cannot see what you don't look for...

  For F-35 like for Dassault aircrafts you have NO idea....

  For a starter I posted the link to an article containing an interview explaining to you that load designed factors can be uppered or lowered for diverse reasons and are not the same from one manufacturer or one aircraft to another...

 Here is a quote from one of the Typhoon design team managers which goes some way to prove this.

 "The ability of carefree handling to control g limits precisely has allowed designers to reduce the ultimate load factor to 1.4, from the normal 1.5, resulting in a lighter aircraft. The airframe is designed for a 6,000h life".

 http://www.flightglobal.com/articles/1999/06/16/52589/agile-thinking.html

 This negates your "I don?t see point" once.

 &nbs
 
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PierreLeGrand    warpig    5/12/2009 6:37:10 PM
Looks to me as if you are mystaking g onset and instantaneous turn rate though.
 
In the roll axis although i have no values for Rafale it is not uncommon to see a g onset of up to 15 g for a roll rate of 290*/sec and it is well under the max load values in all axis.
 
In pitch it would mean a little above half a second before Rafale reaches its soft limit of 8 g, look at the video again and try to figure how fast the aircraft reaches its maximum roll and pitch rates.
 
And since i am in a generous mood...
 
 
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