Evening star., 1929-09-01
AVIATION
BY JOSEPH S. EDGERTON.

was pointed out at Cleveland that
at an engine speed of 1900 revo-
lutions per minute the centrifugal
force of metal blade weighing n
pounds imposes a load OF 70 tons
on the propeller hub. To provide
the maximum of lightneSS with
strength, the present tendency Is
to use duralumin blades attacneo
to steel hubs, it was pointed out.
A difficult problem now being
worked out by the engineers is to
provide a means Of control Tor
altering the blade angle while In
flight which will be neither TOO
slow nor too fast in action, and
yet at the same time will enable
the pilot to make the necessary
settings with the least trouble
and eXertion.
Propeller gearing to produce
lower propeller than engine
speeds, as is done in automobile
prac Ace, was discussed. In a joint
paper prepared by Theodore +.
Wright and r. E. Johnson OF the
CurtiSS Co., it was contended
that the net gain in performance
does not warrant gearing OF en-
gineS rated at less than 400 horse
power, nor for airplaneS weighing
! less than 1000 pounds. They be-
lieve that the trend will be de-
cidedly in favor of the use of
geared-down propellerS in large,
multi-motored transport planes.
232 Plane Types.
A survey made public by the
Aeronautical Chamber of Com
merce shows that the American
public now has 232 approved air
plane types from which to select
private or commercial aircraft
Representatives of most of the
types which have passed the rigid
! Department of Commerce tests
are on display in the Cleveland
Auditorium and adjoining build
ingS.
BiplaneS are in the majority
with 144 Of this type as against 81
monoplaneS. Ten different am
phibianS are on the market, to-
gether with four flying boats and
SeaplaneS and nine types convert
ible for either land or water use
The rapid increase in the mar
ket for cabin planes for both COM
mercial and private use is one OF
the outstanding impreS eSSlo n
gained from the exposition. There
is total of 112 different cabir
planes manufactured under ap'
proved type certificates, as con
traSted with 120 open-cockpi
types, which formerly held clea!
field. There are 80 different two
place sport and training planes or
the market, five of which are O.
the cabin type.
Commercial airplane manufac
turers, meeting under the aus
piceS of the AerOnautical ChambeI
of Commerce, have expressed gen
eral satisfaction with the preSen
airWorthineSS requirements 10.
airplanes set up by the Fedora
Government to protect the Amer
lean public. The airWorthineS!
requirements, which constitute
the engineering code followed BY
commercial airplane manufacture
erS to obtain Government ap'
proval of their planes, were dis
cussed in detail and only minol
notifications recommended. Pos
sible changes in the present spin
ming tests and maximum engine
speed requirements are still under
study.
Distributors Meet.
Faced with the greatest produc-
ton in the history Of the aircraft
industry, distributors and dealers
affiliated with the Aeronautica,
Chamber of Commerce met in
Cleveland to discuss plans for q
national marketing program to
keep abreast of mounting produc-
ton schedules. The formation OF
a national organization of dis
tributors and dealers was viewed
by leaders in the industry as
opening new era in the develop
ment of a nationwide marketing
organization. Underorganization
and not overproduction is the
chief concern of the aircraft in
dustry today, its leaders are
agreed.
Development of sales organiza-
tions extending into every COM
munity is regarded as the step
which has taken the aircraft in
dustry out of the experimental
stage and has placed it upon a
sound economic basis along with
other industries.
Airplane engine production
reached the highest peak in the
history of the aircraft industry
during the first six months of this
wear, when 1926 motors were
manufactured, according to re-
ports made public at the air meet
this week. This report shows an
increase of 78 per cent during the
first six months of this year over
the entire IL months output for
last year. During the same six
months $500 commercial and
military airplanes, with a total re-
tail value of SOS, 100000, were built,
the total for the six months being
so per cent of the total for the
entire year 1928.
nlIMNNIK Ek0T0RY