Wagner "Gegenpropeller" (Contra Propeller) 1918

[Jemiba]

As mentioned in the thread about the steam engine powered bomber, Dr. Rudolf Wagner transferred his ideas
about reducing the losses due to spin of the slipstream of a ships propeller to aircraft and filed a patent in
the year 1915. the basic idea is, to reduce the spin by using a "Gegenpropeller" (Contra Propeller), principally
a set of guide vanes in front or aft of the prop (see Wagner_Gegenprop_schematic.jpg ).
Actually tested on ships and boats, such arrangements showed mixed results. Nevertheless, Dr. Wagner made
several proposals for the use in aircraft (see Wagner_Gegenprop_01.jpg )and even designed a kind of helicopter,
called "Schraubenflugzeug" (screw plane), that should use this principle to overcome the torque from the rotor.
Intended as crane helicopter or flying sanatorium, the contra prop here was integrated in the complete structure
(see Wagner_Gegenprop_02 to _04.jpg ).
During the '20s several different solutions were developed, either fixed or articulated in front of the prop ( see Wagner_Gegenprop_12 and 13.jpg ), or fuselage mounted behind the prop, with the benefit of producing additional
lift (see Wagner_Gegenprop_07.jpg ).

 

[Jemiba]

The twin engined light transport aircraft actually was an indigenous design by Wagner (see Wagner_Gegenprop_11.jpg ),
but the use of the contra prop was proposed for existing types, like the Dornier Wal, too, or even for airships
(see Wagner_Gegenprop_12, _14 and _15.jpg ).
Another indigenous design was made for a ligt single engined aircraft, with a pusher prop driven by a nose mounted
engine via a long shaft. Here the contra prop was integrated into the tail surfaces ((see Wagner_Gegenprop_05 and
_06.jpg ). A similar, but larger design with twin booms was shown as civil transport in Germany, but as heavily armed
military aircraft in the contemporary US press (see Wagner_Gegenprop_08. and _09jpg )

 

[Jemiba]

So, this invention seems to have aroused intention in the US. And tests actually were made during 1929 in
the USA, using an Curtiss HS-2L flying boat provided by the US Navy. This was the reason, to post it here,
instead of the patent or projects section, as the Wagner designs should be regarded as concepts only, but maybe
one of you will stumble over photos of that aircraft.
Results of those tests were disappointing, only for low RPM an increase of efficiency could be stated. At higher
RPM results were worse, than without the guide vanes, probbaly due to increased drag an increased vortexes
behind the prop, so the idea was dropped. Similar proposals were later made during the '30s by the German Prof.
Beetz and in 1940 by Prof. Bock and it is said, that something like a contra prop was shown in a Russian publication
from the mid '30s, too. In practice, the idea was more or less superseded by the co-axial counterrotating propeller.
(Pictures and information from Luftfahrt International N° 26, 1978)

 

[hesham]

Amazing projects my dear Jemiba,


and from a Russian site;


http://alternathistory.org.ua/samolety-s-kontra-vintami-doktora-rudolfa-fon-vagnera


I suggest to transfer this topic to Early Aircraft Projects section.

 

[Nicknick]

With the "CFM RISE" Propfan we see the same principes coming back. You can find quite a lot of those devices on ships (e.g. the Mevis duct) where they tend to have more success.

My favorite solution would be a pusher plane with the cross tail servicing several functions, steering, trimming and creating a pre swirl (automatically done by trimming against the propeller torque).

 

[publiusr]

The O turbine is to be used in wind farms

View: https://www.youtube.com/watch?v=TNpcJn02CM4


Might a modification of this be used for aircraft?