|Aeromatic and Aeromaster propellers, manufactured
by the Koppers Co. are for engines from 65 h.p. to 330
h.p. The three Aeromatic models are constant-speed types
and the Aeromaster is ground-adjustable. Hubs are chrome-nickel-molybdenum and the blades are laminated maple. Weights vary from 28
up to 62 pounds for the larger models.
* The Air-Controlled Automatic Propeller—Licensed
under Patents of Everel
propeller is a two-blade variable-pitch
unit, which is entirely self-contained. The single-piece
hub of chrome-nickel-moly steel retains blade flanges
on large ball thrust bearings. A synchronizer gear between
the blade flanges co-ordinates their movements. Adjustments
for pitch range, balance and lubrication are all accessible
Blades for the Aeromatic are made of thin lamination
of maple or birch bonded with thermal-setting resin to
provide a structure stronger than a natural wood blade.
AEROLOID plastic sheeting is pressure bonded to the exterior
of the blade for protection against abrasion and moisture
Monel leading edge tipping is applied over the AEROLOID
plastic to protect the leading edge of the blades. Threaded
ferrules are affixed to the blade butts by the standard
lag screw method of blade retention. The threaded feature
allows the blades to be removed from the hub without
The fully automatic operation of the AEROMATIC
propeller eliminates the use of any controls from the pilot or
engine on the model 220. The natural, physical forces
acting on the blades and counterweights are utilized
to accomplish the desired pitch change. Substantial performance
advantages are made possible with the Aeromatic due to
the greatly increased propeller and engine efficiencies
afforded by automatic operation. Prevention of engine
damage as well as maximum operating economy is attained
through automatic response to changing conditions of
Shorter Take-off: At take-off the blades
move to low pitch automatically permitting the engine
full take-off power. This gets the plane off the ground
1/3 Higher Rate of Climb: Best climb power is maintained
as the propeller automatically adjusts pitch to correspond
to correct climbing speed. This gets the plane to cruising
level fast, on minimum fuel.
Greater Cruising Range and Speed: Economical cruise power
is maintained as the Aeromatic selects the most advantageous
pitch at all normal altitudes.
Safer Landing: Automatically adjusts its pitch for a
long, flat glide. In the event of overshooting during
landing, full throttle will locate the blades in low
pitch, making take-off power immediately available.
Models 220-1 and 220H are modified versions of the Model
220 with Aeromatic Hi-Cruise control assemblies. The
model 220-1 Hi-Cruise control is actuated manually through
a control cable and bell crank.
The Model 220H Hi-Cruise pitch change mechanism is actuated
by a hydraulic cylinder, which is operated by engine
oil pressure controlled through a special control valve.
The Hi-Cruise control unit permits a selective pitch
change range of several hundred RPM. This feature is
of exceptional value when the airplane is flown at altitudes
above 5000 feet. This feature also permits the choice
of using the propeller as a standard Aeromatic or as
a selective RPM propeller.
These propellers were certified on most of the production
airplanes during the big airplane boom right after WW
AERONCA • BELLANCA
CRUISAIR • STINSON
FLYING STATION WAGON & L-5 • GRUMMAN
WIDGEON • MONOCOUPES • TAYLOR
PIPER SUPER CRUISER & FAMILY CRUSIER • FAIRCHILD
24 • CESSNA
120, 140 & 165 AIRMASTER • JOHNSON
ROCKET• MEYERS • RYAN
NAVION • SWIFT
125 • ERCOUPE • and were being approved
for other makes and models and also were available
for numerous foreign models.
The Propeller with a Brain for Tomorrow’s Plane Aeromatic
Air Controlled Automatic Propeller
Licensed under patents of EVEREL Propeller Corporation
KOPPERS Co., Inc., Bartlett Hayward Division, Baltimore
* Walter E. Everets, was the designer of the EVEREL Single Blade Propeller. During the testing and experimental
stages, Everets, found that the single blade produced
25% greater thrust than the conventional two-blade
Nearly sixty experimental full-sized blades and more
than a dozen hubs and mechanisms were built and tested
before the 40-horsepower model of the single blade was
submitted for an Approved Type Certificate, which was
received for the Taylor A, and the J-2 Cub.
Another Everel propeller is on display at the Pearsons
Air Museum in Vancouver, Washington.