The Coax-P is a
contra-rotating propeller
Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston engine, piston or turboprop engine to drive a pair of ...
developed by
NeuraJet
NeuraJet was an Austrian aircraft manufacturer based in Senftenbach and founded by Hans Neudorfer. The company employees were Neudorfer & Annemarie Humer. It specialized in the design and manufacture of paramotors in the form of ready-to-fly a ...
of
Senftenbach,
Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...
and
Sun Flightcraft of
Innsbruck, Austria for the
Rotax 503
The Rotax 503 is a , inline 2-cylinder, two-stroke aircraft engine, built by BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.Raisner, William: ''LEAF catlog'', pages 6-105. Leading Edge Airfoils, 1995.
As of 2011 the Rot ...
and
Rotax 582
The Rotax 582 is a two-stroke, two-cylinder, rotary intake valve, oil-in-fuel or oil injection pump, liquid-cooled, gear reduction-drive aircraft engine manufactured by BRP-Rotax GmbH & Co. KG. It is for use in non-certified aircraft operating ...
aircraft engines for use on
ultralight aircraft.
[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
An ultralight trike is a type of powered hang glider where flight control is by weight-shift control, weight-shift. These light-sport aircraft, aircraft have a fabric Rogallo wing, flex-wing from which is suspended a tricycle fuselage pod driven ...
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 o ...
. 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
A reduction drive is a mechanical device to shift rotational speed. A planetary reduction drive is a small scale version using ball bearings in an epicyclic arrangement instead of toothed gears.
Reduction drives are used in engines of all kinds ...
. 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
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
Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), diffe ...
*Weight:
See also
*
List of aircraft propeller manufacturers
References
{{Reflist
External links
Photo of the Coax-P
Propellers