Quote:
|
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).