On Wed, 20 Aug 2003 14:30:57 GMT, Ed Rasimus wrote:


Note in your original post and again in the lead to this elaboration
the parenthetical notice that the maneuver was "at a 30-degree angle,
not vertically down."

Just as the description of what Lowell was doing isn't technically a
"Cloverleaf", so also this is not a "split-S." It's a descending hard
turn, almost what is referred to in more modern terminology as a
"sliceback". Whenever you use some descending vertical in a turn, you
decrease your turn radius gaining some radial G from gravity.

To return to the original description of Lowell's maneuver, it sounds
as though he was exercising a series of high and low yo-yos. First, to
control overtake and reduce angles, he pulls the nose up to slow and
minimize overshoot of the target's turning circle. Then from high
slightly outside the target flight path in a lag pursuit position, he
rolls over and lowers the nose to take a cut across the target's
circle and gain closer. A high yo-yo, followed by a low yo-yo.

It's not a yo-yo maneuver Ed, it's purely a horizontal exercise. Let's see if I
can explain it this way for those unfamiliar with the ACM.

Picture a purely circular race track, You have two cars racing around the track,
one on the inside of the track, the other up along the outer wall. Periodically,
the car to the outside of the track pulls down to the inside edge. However, his
tires lose grip and he slides back up to the outer wall again.

In the instance where Lowell was dueling with the Spit XII, both aircraft were
flying in a lufberry. Periodically, Lowell would pinch in, momentarily pulling
lead. However, his P-38 would rapidly scrub off speed and begin to mush,
whereupon he would ease off the elevators and assume his position to the outside
of the Spitfire's turning circle.

This maneuver will only work once or twice, because the Spitfire's smaller
turning radius will eventually prevail. One could certainly pull the nose high
into a yo-yo and cut across the Spit's turn radius, diving into a low yo-yo to
repeat the process. Naturally this assumes that the Spit driver doesn't reverse
out of his lufberry and counter your yo-yo with a rolling scissors. Yet, with
that huge Griffon turning a 5-bladed prop, the Spit XII was loath to roll
against torque (though not as bad as the Mk.XIV) at low speeds. It's difficult
to force an overshoot when it takes forever (relatively speaking) to reverse
direction. Then again, the P-38 was sluggish on the ailerons at low speeds
itself, although a boot full of rudder helps some and will aid in scrubbing
speed. But, either way, the Spitfire has a clean stall speed nearly the same as
the P-38L with the fowlers nearly all the way out.

My regards,

Widewing (C.C. Jordan)
http://www.worldwar2aviation.com
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