The Coax-P is a
contra-rotating propeller developed by
NeuraJet of
Senftenbach
Senftenbach is a community in Upper Austria in the district of Ried im Innkreis
Ried im Innkreis (Central Bavarian: ''Riad'') is a town in the Austrian state of Upper Austria, approximately west of Linz and north of Salzburg. It is the capital ...
,
Austria and
Sun Flightcraft of
Innsbruck
Innsbruck (; bar, Innschbruck, label=Bavarian language, Austro-Bavarian ) is the capital of Tyrol (state), Tyrol and the List of cities and towns in Austria, fifth-largest city in Austria. On the Inn (river), River Inn, at its junction with the ...
, Austria for the
Rotax 503 and
Rotax 582 aircraft engine
An aircraft engine, often referred to as an aero engine, is the power component of an aircraft propulsion system. Most aircraft engines are either piston engines or gas turbines, although a few have been rocket powered and in recent years many ...
s for use on
ultralight aircraft
Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with ailer ...
.
[Bertrand, Noel; Rene Coulon; et al: ''World Directory of Leisure Aviation 2003-04'', page 70. Pagefast Ltd, Lancaster UK, 2003. ISSN 1368-485X]
Design and development
The Coax-P was designed by Hans Neudorfer of NeuraJet and Herbert Hofbauer of Sun Flightcraft. The propeller increases thrust by 15-20% over single propellers and reduces noise levels, especially low frequency noise, while eliminating torque effects.
The propeller system was designed for
ultralight trikes and
powered parachutes
A powered parachute, often abbreviated PPC, and also called a motorized parachute or paraplane, is a type of aircraft that consists of a parafoil with a motor and wheels.
The FAA defines a powered parachute as ''a powered aircraft a flexible or ...
. The latter are especially sensitive to torque effects and the propeller design addresses that issue.
The design has two propellers, each with two composite, ground adjustable blades and uses a 3.7:1 gear box type
reduction drive. The two propellers are powered by two meshing and counter-rotating shafts, powered by helical gear wheels running in an oil bath.
The gap between and the pitch of the two propellers must be exactly right. Neudorfer explains, "when the setting is not exactly right, the air stream from the second propeller meets the retrograde air stream from the first propeller at the wrong angle and all this does is to produce more noise and more turbulence. The correct agreement of the setting angle and the hub gaps for the different propeller hub forms can only be established by doing the finest of setting work. Should the propeller be out of place by only two millimeters the effectiveness declines and the noise level increases dramatically."
Applications
*
Sun Flightcraft Air-Chopper
The Sun Flightcraft Air-Chopper is an Austrian powered parachute that was designed by Herbert Hofbauer and produced by Sun Flightcraft of Innsbruck. Now out of production, when it was available the aircraft was supplied complete and ready-to-f ...
Specifications (Coax-P)
Source: Sunflight
*Propeller blades: composite, ground adjustable
*Number of blades: four (two on each propeller)
*Reduction drive: 3.7:1
gear box
*Weight:
See also
*
List of aircraft propeller manufacturers
This is a list of aircraft propeller manufacturers both past and present:
A
* Aero Ltd. - Poland
* AeroLux Propellers - United States
* Aeroproducts - United States
* Aerosila - Russia
* Airmaster Propellers - New Zealand
* The Airscrew Comp ...
References
{{Reflist
External links
Photo of the Coax-P
Propellers