What RAM is describing above is flying with turn rate vs. turn radius. (Good description RAM, but I will just clarify because your english may confuse a few folks. It's better than my Spanish though!)
The 190 series does not have a small turn radius, but it has a high turn rate. So while the Spit may turn in a much smaller circle than the 190, the 190 can fly a larger circle but at a faster speed, and still make a 360 degree turn very quickly. The trick is to understand how your plane compares to the opponent's plane, and choose the correct way to engage him based on that.
Basically, the fighter with a smaller turn radius should choose a nose to nose fight (a one circle fight), while the fighter with a higher turn rate (but a larger turn radius) should choose a nose to tail fight (a two circle fight).
Check out this page I found:
http://www.vfa-13.com/takeoff/topgun/acm4.html Now bear in mind that this isn't simply about the performance of the aircraft. What speed both of the aircraft are flying at the start of the engagement has a huge bearing on how tight the turn radius will be, and what your turn rate will be. For the intial few moves of the engagement, a much faster bogey is going to be the rate fighter, regardless of comparitive plane performance. A Zeke at 400 Mph versus my Jug at 250 and the Jug has the radius advantage, at least to start. That is an extreme example, but the point is valid. Remember that as you fly above your best sustained corner velocity, your turn rate and your turn radius both increase. Take this into account when you are engaging a bogey, and don't try to use radius fighter tactics if you are travelling too fast and thus do not have a small turn radius.
Some rules of thumb. In a radius fighter (one with a small turn radius), you want to engage in nose to nose, one cirle fights. This means that you turn whatever way he turns. If he goes up, you go up. If he goes North, you go north. Speed and energy permitting of course. In a rate fighter (one with a faster turn rate), you want to force a two circle, nose to tail fight. This can be tricky, especially if the bogey turns upwards, since diving at the merge will likely lose you the fight. However, if we talk completely in the horizontal, the rate fighter generally would want to turn away from the direction of the break of his opponent. As you can see from the examples, is thins way the rate fighter can use his advantage.
Now, there are more ways to use a rate advantage than that. Primarily they all have to do with keeping superior speed through the use of lag pursuit and out of plane maneuvers such as high yoyos and such to maintain position. It is even possible to win one circle fights in the vertical, although very difficult. It is this challenge that draws many folks to planes such as the P-51, the FW-190, and my favourite the P-47.
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Sean "Lephturn" Conrad - Aces High Chief Trainer
A proud member of the mighty Flying Pigs
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