Evening star., 1942-09-07


The Lockheed Lightning had its
prototype in a two-engine fighter,
the Grumman Skyrocket, which the
Navy tried out some years ago and
rejected because of its clumsiness in
maneuver. The Thunderbolt was
made possible by the Pratt & Whit
ney Double Wasp motor. which was
installed In a model about six years
old. Even Maj. Seversky, the orig
inal designer, owns to skepticism,
and writes as follows: The fact that
the PAT now looks as good as any
thing the Axis has already exhibited
in combat does not preclude the
possibility that meanwhile the enemy
has perfected superior planes" +"
Mustangs to Replace P-40s.
The question of American medium
and low altitude pursuits involves
the history of the turbo-super-
charger and the General Motors
liquid cooled Allison motor These
ships are planes of the Curtiss P-40
series, ranging from P-40C Toma-
hawks and P-40D Kittihawks to
P-40F Wawhawks; the Bell P-39
Airacobra and the North American
Psi Mustang. A British lease-lend
craft of recent model, the Mustang
it not yet In American service but
is being groomed to replace the P-40,
the basic model of which is six
years old or more. 1t is no secret
that the P-40s would already have
been dropped if they were not in
considerable daily production
The turbo-supercharger, with a
fan driven by the motors exhaust
gases, Is used only in American
planes. Other countries use a ver-
sion in which the fan is geared to
the driving shaft. The turbo-super-
charger was patented April 18, 1922,
by Sanford A. Moss, now consult
ing engineer for General Electric
In an effort to escape clouds, icing
and storms, air passenger lines be-
gan experimenting with this device
in 1886 and thereby invented sub
stratosphere fight. The first super
charger was installed in Flying
Fortress during 1898. A year later
before the outbreak of the present
war; it was made standard equip
ment for all Navy planes, including
fighters.
Since the Navy employs air
cooled motors exclusively in its
planes and since they have always
powered the Armys bombers, the
Wright Cyclones and Pratt & Whit
ney Wasps have long been super
charged. The Pratt & Whitney
Wasp, an 18-cylinder job of 2,0oG
horsepower, made possible the de-
| velopment Of the Thunderbolt from
an old model devised by Maj. Sc
versky. The Wright 14-cylinder
Double Cyclone develops l 1000 horse
power, and It's new Duplex Cyclone
with 18 cylinders, mounts to horse
power of 1900.
For plausible reasons having
chiefly to do with air resistance, the
Army preferred to equip it's fighters
with liquid d-cooled motors. The
American engine of this type is the
Allison, the former horsepower OF
which has recently been stepped UP
from 1,150 to 1925. 1t drives the
Lockheed Lightning, Airacobra ane
Mustang.
Allison Motor Dropped.
Early this year the vital import
ance of high and medium altitude
combat became visible to the blind.
est. 1t was then realized that the
Allison, in addition to relatively
weak power, had no supercharger
With frantic haste, this motor wa.
dropped from the P-40 and in it!
place was installed the British SUI
percharged Rolls Royce Merlin Xxx
manufactured in the United State.
by the Packard Motor Co. Thu!
was created the P-40F, first OF tn,
Curtiss series to rise from low tt
medium altitude capacity.
Allison was ordered to furnish it
motors with superchargers. The en-,
gines of the Lockheed Lightning
thus improved, are special jobs. TIL,
Airacobras are to be raised from
low to medium height performance
through the installation of the SUI
percharged Allisons. This will re.
quire considerable re-designing
since the supercharger is device o1
no small weight and size, and th'
P-39 is already SO compact thai
1t could give lessons in economy OF
space to sardine canner. Thanks
to modern and superior lines, the
Mustang commands a 22,000-foot
ceiling with an ordinary Allison.
1t was the Allison's weakness.
which compelled the equipment OF
the Lockheed Lightning with two
motors, mounted on twin booms and
exerting an aggregate horsepower
of 1850. The Lightning climbs its
first mile in a minute and develops
a speed of more than 400 miles ar
hour despite its weight of 13,50(
pounds, twice that of the average
pursuit. On account of its con-
struction, however, the Lightning is
regarded as being highly unma-
neuverable.
Backward in Liquid Engines.
American backWardness in de
veloping the liquid cooled motor i
shown by the fact that both tn
British and Germans have in serv
ice today supercharged engines 0
this type with horsepower in exces
of 1900. They are the Daimler
Benz and Napier Sabre. The Arm,
Air Forces have refused to avail
themselves thus far of the Maple
Sabre, on the ground that it is still
experimental" Neither has Ali
son been encouraged to put int
production 24-cylinder liquid
| cooled model of 1850 horsepower
which was exhibited at the New
York Worlds Fair more than thre
years ago.
Americas failure to keep abreas
of the times in the matter O
liquid-cooled motors is particularly
regretted in the case of the Aira
cobra, designed by Lawrence D. Bel
on the theory that air fighter
should not be planes with guns bu
firepoWer on wings. No other pur
suit is so savagely armed, for it car
ries 37-mm. cannon and a batter
of light and heavy machine guns