Energy Maneuverability

[MadBlaster]

Originally Posted by JG14_Josf

Notice how the two Accelerated Stall lines are not the same as would be expected if the Accelerated Stall lines were made the same because they were based ONLY on calculations. Those lines would be THE SAME shape if they were calculated instead of tested and plotted based upon test results.
They are probably different because they are based on flight tests, not calculations.

if I were to guess, and without knowing anything about this test, I think the lower red and blue curves are without g suit, the higher curves with g suit. if you notice, the convex points (most outward g value) for both the non-g suit curves (assuming that is correct assumption) is around 5.5. g curve. This value seems reasonable.

early ww2 planes, I do not believe were equipped with accelerometers to measure the g. Maybe the p47, iirc. So, this windup test, I don't think it is realistic to use that for your determination, if you wish to remain a faithful, non-quake pilot. If you start using g-meter, wonder woman view, or digging into the code, that might make you quake player by default.

[IvanK]

Nothing to do with G Suits in this chart. The red and Blue convex lines merely represent the sustained G that each aircraft can pull without energy loss i.e. Ps=0. The Red line represents the Mig15 sustained turn boundary, The Blue line the F86F (doesnt say hard or slatted wing) sustained turn boundary. The left hand margin is the Lift limit, the top the structural limit, the RHS the Vmax limit.

This chart is pretty historical as it was one of Boyds first comparative EM charts. It is my belief that this chart was in fact based totally on calculation. Its origin is I believe from a presentation Vu graph used by Boyd in one of his early presentations. The original graph was taken from Boyds archival papers. I recall its covered in the book "Boyd the fighter pilot that changed history" by Coram.

[MadBlaster]

Originally Posted by IvanK

Nothing to do with G Suits in this chart. The red and Blue convex lines merely represent the sustained G that each aircraft can pull without energy loss i.e. Ps=0. The Red line represents the Mig15 sustained turn boundary, The Blue line the F86F (doesnt say hard or slatted wing) sustained turn boundary. The left hand marhin is the Lift limit, the top the structural limit, the RHS the Vmax limit.

This chart is pretty historical as it was one of Boyds first comparative EM charts. It is my belief that this chart was in fact based totally on calculation. Its origin is I believe from a presentation Vu graph used by Boyd in one of his early presentations. The original graph was taken from Boyds archival papers. I recall its covered in the book "Boyd the fighter pilot that changed history" by Coram.

ah well thanks for clarification. it seems coincidence though. wiki says gloc occurs around 5 g for average human. so to get to those outer performance curves, you would need a g suit.

so, i wonder if the lower curves maybe are just normal operating curves and the outer ones, performance curves under combat condition, or something like that?

[IvanK]

The lower curves are simply Ps=o lines that represent the Sustained G (at the altitude the chart is calculated for) that each aircraft can sustain with out losing altitude or TAS.

Correction to the Book title its

"Boyd The fighter pilot who changed the art of war " essential reading if you are into this stuff. The book covers in great detail how these early EM charts were calculated... the story about how they got the computing assets and time is a classic.

http://www.amazon.com/Boyd-Fighter-P.../dp/0316796883

Boyd was the father of the OODA loop.

[MadBlaster]

Originally Posted by IvanK

The lower curves are simply Ps=o lines that represent the Sustained G (at the altitude the chart is calculated for) that each aircraft can sustain with out losing altitude or TAS.

Correction to the Book title its

"Boyd The fighter pilot who changed the art of war " essential reading if you are into this stuff. The book covers in great detail how these early EM charts were calculated... the story about how they got the computing assets and time is a classic.

http://www.amazon.com/Boyd-Fighter-P.../dp/0316796883

Boyd was the father of the OODA loop.

got it now! thanks.

[ATAG_Doc]

Originally Posted by IvanK

The lower curves are simply Ps=o lines that represent the Sustained G (at the altitude the chart is calculated for) that each aircraft can sustain with out losing altitude or TAS.

Correction to the Book title its

"Boyd The fighter pilot who changed the art of war " essential reading if you are into this stuff. The book covers in great detail how these early EM charts were calculated... the story about how they got the computing assets and time is a classic.

http://www.amazon.com/Boyd-Fighter-P.../dp/0316796883

Boyd was the father of the OODA loop.

Even better http://www.c-spanvideo.org/program/158365-1

But I believe this topic is well over the heads of your average person that's plays this GAME and doesn't care. But there is a magazine for everyone I guess.

[JG14_Josf]

I think the lower red and blue curves are without g suit, the higher curves with g suit.

Please consider the possibility that the Corner Speed point at the top of the graph is the maximum turn performance for those planes as they were flown during testing by Chuck Yeager and John Boyd as they had available to them a captured Mig and F-86s. John Boyd was working on finding out why the F-86 was defeating the Migs.

Note the much smaller turn rate for the F-86 and the much faster turn rate despite the Mig 15 pushed to a higher g on that graph.

The other curves are Sustained Turn Performance curves or Specific Excess Power at 0, or Ps=0 whereby the plane is not gaining or losing any energy while it is on that line at those speeds, those g loads, and that line is a turn at those speeds, full power, where the pilot is flying a plane in a turn not gaining or losing altitude and the far right point is Top Speed and as soon as the pilot starts turning in a level turn a new plot is added to the line and the pilot could stay at that plot with a very wide turn not gaining and not losing altitude, and the pilot can tighten the turn and make a new plot, not gaining altitude, not losing altitude, not accelerating, not decelerating, flying at that bank angle, full throttle, coordinated turn, full power, and if the bank angle is moved even steeper, and steeper, maintaining level flight, the end result is a stall and that is the far left point on that lower curve which is The Sustained Turn Performance Envelope, and notice, please, how the Mig is much better at Sustained Turns compared to the F-86 except if both planes are turning a Sustained Turn at speeds above .7 Mach at which time the F-86 can out turn the Mig if the Mig pilot tried to follow at that airspeed (but the Mig can just cut the turn).

The obvious interesting observation that may be inspired by the differences in the Accelerated Stall line, if you are now following the meaning of those line on that chart, is the question as to why the Mig Accelerated Stall Performance Deteriorates rapidly with speed compared to the F-86.

If you have the Corner Speed g load LINE confused as a g suit line and you have the Sustained Turn Performance LINE confused with a non g suit line, then you may also have the Accelerated Stall LINE confused too.

I don't know, but I appreciate the effort to learn from those Charts because they are made for a very specific reason relative to Energy Maneuverability which is the modern method of quantifying the specific advantages one plane has over another plane UNAMBIGUOUSLY.

Interesting to that end is the concept of wing deformation under g load and such things could be factors contributing to changes in the theoretical or calculated accelerated stall line as the actual plane can or cannot actually fly on that theoretical ideal Accelerated Stall Line.

The Fw190, in particular, as reported by more than one source, was known to have a wing that deformed under g, and the twist would twist out of it, causing the plane to become less stable, to the point where the pilot had to relax stick pressure or the g load would increase because the wing deformed and therefore lift forces were increasing as the washout was untwisted from the wing.

If you want I can site sources. I have one source on the shelf in the form of a book by Eric Brown who was a World War II test pilot (British).

[Robo.]

Originally Posted by JG14_Josf

The other curves are Sustained Turn Performance curves or Specific Excess Power at 0, or Ps=0 whereby the plane is not gaining or losing any energy while it is on that line at those speeds, those g loads, and that line is a turn at those speeds, full power, where the pilot is flying a plane in a turn not gaining or losing altitude and the far right point is Top Speed and as soon as the pilot starts turning in a level turn a new plot is added to the line and the pilot could stay at that plot with a very wide turn not gaining and not losing altitude, and the pilot can tighten the turn and make a new plot, not gaining altitude, not losing altitude, not accelerating, not decelerating, flying at that bank angle, full throttle, coordinated turn, full power, and if the bank angle is moved even steeper, and steeper, maintaining level flight, the end result is a stall and that is the far left point on that lower curve which is The Sustained Turn Performance Envelope, and notice, please, how the Mig is much better at Sustained Turns compared to the F-86 except if both planes are turning a Sustained Turn at speeds above .7 Mach at which time the F-86 can out turn the Mig if the Mig pilot tried to follow at that airspeed (but the Mig can just cut the turn).

Very well, we had this very conversation just couple of weeks ago, doghouse of Spitfire Mk.I and Bf 109E. The last bit in the brackets is what forum user Crumpp failed to understand. He is now unfortunately banned from the forums so he can not add anything to that discussion.

It was established though that the speed at which the 109 gains upper hand in sustained turn parameter is 400kph (equivalent of those 0.7mach in the Sabre vs. MiG graph).

Would you would mind going back to my posts and answer my questions taht would be greatly appreciated. I went long distance (literally lol) reading your posts and replying in detail.

[MadBlaster]

Originally Posted by JG14_Josf

The other curves are Sustained Turn Performance curves or Specific Excess Power at 0, or Ps=0 whereby the plane is not gaining or losing any energy while it is on that line at those speeds, those g loads, and that line is a turn at those speeds, full power, where the pilot is flying a plane in a turn not gaining or losing altitude and the far right point is Top Speed and as soon as the pilot starts turning in a level turn a new plot is added to the line and the pilot could stay at that plot with a very wide turn not gaining and not losing altitude, and the pilot can tighten the turn and make a new plot, not gaining altitude, not losing altitude, not accelerating, not decelerating, flying at that bank angle, full throttle, coordinated turn, full power, and if the bank angle is moved even steeper, and steeper, maintaining level flight, the end result is a stall and that is the far left point on that lower curve which is The Sustained Turn Performance Envelope, and notice, please, how the Mig is much better at Sustained Turns compared to the F-86 except if both planes are turning a Sustained Turn at speeds above .7 Mach at which time the F-86 can out turn the Mig if the Mig pilot tried to follow at that airspeed (but the Mig can just cut the turn).

I think this test could be re-created in game. Four pylon type objects set up in box pattern, equi-distant, as lying on the edge of the imaginary turning circle. Fly the circle, note the time of completion from 0 to 360 degrees and IAS. Deviation from the flight path is fail. Loss of alitude is fail. As per above, follow each successful completion with another test. Shorten the distance between the pylons by some incremental amount. Repeat until the test can no longer be completed without loss of altitude or deviation from the flight path. I don't even think you need g meter. But I guess it would be helpful while conducting the test to make sure you are flying constant g.The test I described before, I think that would give you the instantaneous value. So, if you think 109 v spit diagrams are similar to mig v sabre? Then I agree with you. You need to do both type of test, sustained and instantaneous turn rate, to get full picture. I think. Probably would need to use device link and make tracks of each test to ensure flight path is followed, altitude is maintained, full power settings, ...etc. If your at sea level, need for tas conversion may not be necessary. I guess it boils down to how accurate you want to be in this.

[TomcatViP]

Originally Posted by JG14_Josf

Please consider the possibility that the Corner Speed point at the top of the graph is the maximum turn performance for those planes as they were flown during testing by Chuck Yeager and John Boyd as they had available to them a captured Mig and F-86s. John Boyd was working on finding out why the F-86 was defeating the Migs.

Note the much smaller turn rate for the F-86 and the much faster turn rate despite the Mig 15 pushed to a higher g on that graph.

The other curves are Sustained Turn Performance curves or Specific Excess Power at 0, or Ps=0 whereby the plane is not gaining or losing any energy while it is on that line at those speeds, those g loads, and that line is a turn at those speeds, full power, where the pilot is flying a plane in a turn not gaining or losing altitude and the far right point is Top Speed and as soon as the pilot starts turning in a level turn a new plot is added to the line and the pilot could stay at that plot with a very wide turn not gaining and not losing altitude, and the pilot can tighten the turn and make a new plot, not gaining altitude, not losing altitude, not accelerating, not decelerating, flying at that bank angle, full throttle, coordinated turn, full power, and if the bank angle is moved even steeper, and steeper, maintaining level flight, the end result is a stall and that is the far left point on that lower curve which is The Sustained Turn Performance Envelope, and notice, please, how the Mig is much better at Sustained Turns compared to the F-86 except if both planes are turning a Sustained Turn at speeds above .7 Mach at which time the F-86 can out turn the Mig if the Mig pilot tried to follow at that airspeed (but the Mig can just cut the turn).

The obvious interesting observation that may be inspired by the differences in the Accelerated Stall line, if you are now following the meaning of those line on that chart, is the question as to why the Mig Accelerated Stall Performance Deteriorates rapidly with speed compared to the F-86.

If you have the Corner Speed g load LINE confused as a g suit line and you have the Sustained Turn Performance LINE confused with a non g suit line, then you may also have the Accelerated Stall LINE confused too.

I don't know, but I appreciate the effort to learn from those Charts because they are made for a very specific reason relative to Energy Maneuverability which is the modern method of quantifying the specific advantages one plane has over another plane UNAMBIGUOUSLY.

Interesting to that end is the concept of wing deformation under g load and such things could be factors contributing to changes in the theoretical or calculated accelerated stall line as the actual plane can or cannot actually fly on that theoretical ideal Accelerated Stall Line.

The Fw190, in particular, as reported by more than one source, was known to have a wing that deformed under g, and the twist would twist out of it, causing the plane to become less stable, to the point where the pilot had to relax stick pressure or the g load would increase because the wing deformed and therefore lift forces were increasing as the washout was untwisted from the wing.

If you want I can site sources. I have one source on the shelf in the form of a book by Eric Brown who was a World War II test pilot (British).

Simply said, a faster plane fighting at higher speed will loose less E than a slower plane fighting him at the same speed. So keep your Speed high and turn fast. Soomething that some here never agreed to understand (by conformism). Great to hear your voice on that theme here !


Illustration:
1.Kelly J. was never ashamed of the 104 small wing.... He was asked to build a high manoevrable supersonic plane !
2. this where the canards Eu planes are missing the 5th gen contest (the Raf being the less affected in fact): too draggy at high speed to really move like a fish!

EDIT: there is some archive movies on Youtube with Yeager and Boyd flying the 15. I think I posted somewhere (Warclouds ?) a link to a doc