New Oberursel Ur2

[FOKKERJ]

Originally Posted by franzkait

cylinders are made from solid . start with 90 lbs and end up with 6 lbs

Do you use CHROME MOLY? Molybedemen, 4000 series?

[Taz]

franzkait- I am aware of some of the differences between the early and late Ur.IIs, for example, the lightening holes in the rocker arms on the late versions. Did the late models go to five compression rings like the 9Jb and what are some of the other differences?

Taz
Terry Phillips

[franzkait]

propeller hub

[franzkait]

rocker arm housing on top of cylinder

[franzkait]

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[franzkait]

all patterns are made from wood , coated with graphite to get it aut of the sand . The blue color is for steel casting like green is for allu . Some parts are made from chrome moly 4140 .
you can not compare the Oberursel pistons with Le Rhone pistons . Oberursel has allu pistons with 4 modern cast iron rings .I think most parts are different from the Dr1 Ur2 to the E5 Ur2 .

[j ferguson]

These are wonderful photos and a very interesting project. Is it possible to show more photos of crankcase casting process, raw casting, and also some photos of crankcase machining process?

thank you for sharing this,

john ferguson

[franzkait]

I still have 3 unmachind crankcase castings , very heavy items .after machining you can take them away with 2 fingers

[franzkait]

half machined crankcase
Oberursel and Le Rhone piston with ring
new Le Rhone Pistons

[Taz]

franzkait- Great photo of the two piston types. The Oberursel had four compression rings vs the five on the 9Jb and also had two oil grooves where the 9Jb had none. Are you using LeRhône or Oberursel style pistons in your engines? The LeRhône piston pins are much simpler, too, than the ones threaded for a set-screw on the Oberursel.

The workmanship you are showing is quite amazingly good. I hope I get to see and hear one run some day soon.

Taz
Terry Phillips