Quote:
Originally Posted by janpitor
Downthrottling is a good think to reduce speed when needed, but you lose energy then. It is much better to execute high yoyo, thus reducing speed but gaining potential energy.
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This makes perfect sense for jets, and perhaps one-shot rocket aquisition: In WWII the 2% gun hit rate (Luftwaffe study of the average hit rate on bombers) requires you to stay awhile behind your target, so getting out of alignment is always a bad idea...
Spiralling down for the pursued, in WWII, is also often a bad idea, since if he wins the turn contest like this, he will be far too low to raise his nose to fire above himself at the former pursuer... This is why WWII turning contests tend to be
horizontal, and a pursued aircraft will spiral down
only to compensate the fact that it can't compete in turns with the pursuer: This surrendering of the "high ground" by the pursued usually only delays the inevitable, unless he is lucky...
None of this is of great importance to jets where only speed matters...
It is very clear that "energy-management" tactics like high or low "yoyos" are very rare in WWII, quick short-term downthrottling being more common to avoid overunning... (This is clearly very different from what happens in the link below...)
Second, it is clear that the P-51D in this case did not have excess speed: He was being gained on in the turn from behind!:
http://www.spitfireperformance.com/m...an-24may44.jpg
The purpose of downthrottling in this case is obviously to increase the
sustained turn rate by reducing its turning radius... Or just reducing the turn radius...
Unlike jets, props do not need more airspeed going into the intakes to generate more power at the rear: On prop/piston aircrafts, the slower they go the more power they have, and this acts as a "floor" that prevents stalling in sustained turns, but it tightens the radius a lot by relieving the traction power off the wings...
The piston/prop "energy" is thus mostly dependent on the engine, and too much power on a powerful prop engine will pull you out of your tight
sustained turn.... On a jet, the turn will be tighter with more speed until you reach the "Corner Speed".
These WWII prop aircrafts tended to promote prolonged sustained level turn fighting, unless one side often had the height advantage (Me-109 Eastern Front), a centralised armament that could hit in a concentrated way over a great range of distances: A fast closure brings the target closer rapidly: Me-109 and P-38... Or a very flammable target, as the fast closure rate of Boom and Zoom allows only a brief hit: Japanese aircrafts...
As the actual combat example I linked demonstrates (being on the deck over multiple 360°s, it elliminates all variables), Piston/prop traction power requires completely different thinking from what jets do: The combat knowledge in one area is utterly inapplicable to the other, which is something I am sure post-war theorists like Shaw failed to recognize...
Gaston