Different abreviations for German Engines?

[Volker_Nemsch]

Several times I stumbled across different markings or names for the Oberursel rotary engines:

-- U.
-- Ur.
-- UR.

Normally the Germans used two letter abbreviations for the different engines (Bz. for Benz or Mb. for Maybach). Further developments of German engines are normally named with a small letter directly behind the roman figures.

Is there a list with the correct descritptions or names of all German engines existing?

Thanks in advance!

[Dan_San_Abbott]

Volker Nemsch:
I have a German document that lists all the engine makers and engines. Oberusel engines are listed as U0, UI, UIII, URII, URIIa, URIII and URIIIa.
Happy New Year,
Dan-San

[AchimEngels]

Volker,

German aero engines have been classified by their power Output:

0 * * * * * *xxx - *80 PS * * * * * *
I * * * * * * 80 - 100 PS
II * * * * * 100 - 150 PS
III * * *150 - 200 PS
IV * * *200 - 300 PS * * * * * *
V * * *300 - 400 PS
VI * * *400 - 500 PS * * * * * *
VII * * *500 - xxx PS

In the case of the Motorenfabrik Oberursel Aktiengesellschaft there was a small problem with these classifications.

The first rotary they produced was a copy of the French Gnóme which in turn was based on an industrial engine (produced at Oberursel) which the French produced under license before the war. This engine used a underpressure guided inlet valve and was named "Gnom". In return and in memory for the success the french had with this license built industrial combustion engine, they named their rotary which worked to the same principles the "Gnóme" which was just the French translation for the German word "Gnom".

The official abbreviation for the company of Motorenfabrik Oberursel Aktiengesellschaft was "U".

So they produced the U.0 of 50PS and 80 PS, the U.I of 100 PS and the U.III of 160 PS.

The French company later went together with another Frenchman of the Name of Verdet who also designed a rotary, but of different working principles which was more reliable than the "Gnóme". Since the company was located at the river of Rhóne the engine quickly became known as the "Le Rhóne" engine, but this was signifying nothing more but the different working principles.

When the Motorenfabrik Oberursel A.G started to produce "Le Rhóne" type engines they had a problem since suddenly a new designation for the engines was needed to avoid confusion with other, earlier engines of the same power output. The conclusion was to change the companie´s abbreviation to "UR" or "Ur.". This was chosen first because it was the abbreviation for "Ursel" which was a small river at the city of Oberursel where the company was located and because it signified the "Rhóne" principle.

This is the reason why we know of a Oberursel "U.III" (14 cylinder twin row rotary of 160 PS) and a Oberursel "Ur.III" (11 cylinder 140-160PS rotary engine.

Other manufacturer abbreviation where:


Ad * * *Adler * * * * * * * * * * * *
As * * *Argus
Bus * * *Basse & Selve * * * * * *
Bz * * *Benz
C * * *Conrad * * * * * * * * *
D * * *Daimler
Dz * * *Deutz * * * * * * * * * * * *
Goe * * *Goebel
Kg * * *Körting * * *
Man * * *MAN
Mana * * *MAN Augsburg * * * * * *
Mb * * *Maybach
Nag * * *NAG * * * * * * * * * * * *
O * * *Opel
R * * *Rhemag * * * * * * * * *
Rp * * *Rapp
Sh * * *Siemens & Halske * * * * * *
St * * *Stoewer
Sw * * *Schwade * * * * * * * * *
U (UR) * *Oberursel

This and more you would have known if you would have read my book "Die Umlaufmotoren der Motorenfabrik Oberursel A.G." *;D - English translation is on its way...althoiugh growing slowly.... :-/

By the way: Balloonbuster: As you can see there are German books out there on the topic. You just have to read them! *

Best

Achim

[Dan_San_Abbott]

engel:
you forgot to list the BMW designator for the Bayerische Moteren Werke A.G. München.
Mr. Abbott

[AchimEngels]

Thank you Abbott for pointing this out.

Engels

[Roundel]

Fascinating information. After WWI, the joint name "Gnome-Rhone" was adopted by the French company. Before today, I had thought that they were two companies that merged postwar.

Around WWI, there was a line of compressed air model airplane engines that were sold in the USA under the name "Nomie," which might have been derived from "Gnome."