In a WWII documentary
film featuring the exploits of the Vought
F4U Corsair in combat with the Mitsubishi
A6M Zero, mention is made of a well known
performance issue in the Zero. It is a
mystery that continues to this day.
At
20:35 in the film, a Corsair pilot comments, “We
could turn in either direction with ease.
And the Japanese Zero couldn’t do that. It
couldn’t turn to the right. So in a
high-speed dive with him on your tail, you could
turn to the right, he couldn’t make it and go on
by, so you turn back and ‘Hey, look what I've
found!’”
Among the many references that
your puzzle-master consulted is this one…
Marine
Captain Kenneth Walsh described how he
used information from the Zero test
flights to finish the war with 17 aerial
victories over Zeroes: “With [a] Zero on
my tail I did a split S, and with its
nose down and full throttle my Corsair
picked up speed fast. I wanted at least
240 knots, preferably 260. Then, as
prescribed, I rolled hard right. As I
did this and continued my dive, tracers
from the Zero zinged past my plane’s
belly. From information that came from
Koga’s Zero, I knew the Zero rolled more
slowly to the right than to the left. If
I hadn’t known which way to turn or
roll, I’d have probably rolled to my
left. If I had done that, the Zero would
likely have turned with me, locked on,
and had me. I used that maneuver a
number of times to get away from Zeros.”
Both
the Corsair and the Zero are configured laterally
symmetrical, and their respective
propellers rotate in the same direction --
clockwise -- as viewed from the cockpit.
Parameter
Estimations
F4U Corsair
A6M Zero
Ratio (C/Z)
Length ft
33.3
29.7
1.12
Height ft
16.1
10.0
1.61
Center of Gravity ft
8.5
8.3
1.02
Empty Weight lb
8,982
3,704
2.54
Loaded Weight lb
11,432
6,164
1.85
Power Plant hp
2,100
950
2.50
Propeller Diameter ft
13.0
10.0
1.30
Wingspan ft
41.0
39.3
1.04
Wing Area ft2
314.0
241.5
1.30
Wing Loading lb/ft2
36.4
25.5
1.43
Maximum Speed mph
417
332
1.26
All aviators will be reminded of
one interesting asymmetry in aviation called the P-Factor,
which makes airplanes spontaneously yaw leftward
-- but in a climb, not a
dive...
The
upward inclination of the fuselage
tilts the plane-of- rotation of the propeller
away from its normal orientation --
perpendicular to the flight path.
Accordingly, the downward-moving blade on the
righthand side of the aircraft is advancing at
an angle into the relative wind and
thus developing more thrust
than the upward-moving blade on the lefthand
side, which is retreating out of the
relative wind producing less thrust.
Solvers must conclude that the
P-Factor is not operative at high speed in a
dive. Based on comments received from a
number of aviators@niquette.com, it sure looks like there is an
opportunity for a Puzzle
with a Purpose...
What
is your explanation for why the
Zero does not turn right as quickly as the
Corsair?
In a