WWI aircraft engines - specification and performance - Part I: early german rotaries.

[Greybeard]

Hi guys!

picking from a nice compilation of engine data, collected by Adlershof test center prior and during war, assembled in the 1930s by "militärwissenschaftliche abteilung" and eventually published in the 1970s, I thought to share main ones.

Firma..............Jahr...Z..E..K..PS..Bohr-Hub...n...kg...Bz..Öl

Oberursel-Gnôme..1913/14..7..U..L..84..124x140..1190..87..315..80

Oberursel U I....1914/16..9..U..L.110..125x150..1200.145..320..55

Oberursel U 3....1914/16.14..U..L.155..124x140..1200.193..345..90

Legenda:
Jahr: Year
Z: No. of cylinders
E: kind of motor - U=rotary
K: type of cooling - L=air
PS: horsepower
Bohr-Hub: Bore-Stroke
n: RPM
kg: weight
Bz: petrol specific consumption (g/PSxH)
Öl: oil specific consumption (g/PSxH)

Please notice how what should be "U0" is named "Oberursel-Gnôme" as well as there's any "U2" or "UII" (which I was unable to find also on Technische Berichte).

Cheers
GB

[Aquilius]

Hi Greybeard,

are these pre-war files documents from the "Kaiserpreis" engine contests?

Would love to know which other contestors took part then. There should have been also two Daimler Mercedes rotary engines. Don't know if they were ever used to power an aircraft.


Then these roman-number designations with company abreviation are no company designations, that are classifications given by the "Prüfanstalt der Fliegertruppe" (IdFlieg?). They were given according to the power rating.

0 - up to 80 hp
I - 80-100 hp
II - 100-120 hp
III - 120-150 hp
IV - 150-250 hp
V - 250-500 hp

Probably the 80 hp Oberursel-Gnôme (licence model) was later named "U.0".
Then the 110 hp LeRhône copy for whatever reason is always to find as "UR.I".

Acutal my notes of the later developements are little confusing.
Don't know if there was an "U.II" at all.


Cheers

Aquilius

[Greybeard]

Hi Aquilius.

They are all data coming from engine tests performed at Adlershof. This is the only commonality.

They include also pre-war files, but no reference to any contest is done, sorry.

The only other early german rotary tested in addition to above mentioned ones that I find is:

Firma..............Jahr...Z..E..K..PS..Bohr-Hub...n...kg...Bz..Öl
Schwade-Stahlherz.1913/14.7..U..L..50...110x120.1180..78....-...-

Thanks for power-rating based identification codes: they should be referred just to "nominal" rated output, since actual PS look out of range (e.g.: U I is 110 PS)

I can't find any UR I (whilst there are UR II and III). 110 HP Le Rhône is reported too, without the "y" which markes, on this document, captured examples.

S!
GB

[YavorD]

Originally Posted by Aquilius

...
Then the 110 hp LeRhône copy for whatever reason is always to find as "UR.I".
...

Hi, Aquilius!
The LeRhône 9J/Jb variant produced by Maschinenfabrik Oberursel in 1917/18 was designated UR.II (or UR.2; or Ur.II). It was considered as 120 - 130 P.S. engine.
Regards,
Yavor

[Aquilius]

Thanks Yavor,

I had a note of an "U.II" and "1918".

But, well, I'm sorting and sorting my files every day. Too many things to fix.
The engine part has not long ago cought my interest. Just where to take all the time from?



Cheers

Aquilius