The Oberursel UR-2 rotary engine, rated at 110hp, was the type used to power the Fokker Dr.I triplane. Built by the Oberursel Motoren Gesellschaft of Frankfurt, Germany, it was an exact copy of the famous French LeRhone 110-hp rotary engine.
.jpg) |
| National Museum of the US Air Force, Dayton, Ohio, USA. |
Step 1 in the assembly manual starts with assembling the nine engine cylinders. After washing the plastics parts in warm soapy water to remove oils from the molding process, all the cylinders were glued together. I will clean up the mold lines and then proceed gluing the other items into place.Cleaning up the seam line on the cylinders is taking a few evenings to complete. Getting in-between all those cooling fins was pretty difficult, but I did finally come with a solution. I used 660 grit sandpaper wrapped around an 8" razor blade with the sandpaper being on the sharp side of the blade. This way I could get in between the cylinder fins pretty easy, now the process is speeding up a bit. I have about 5 cylinders complete with the rocker arms and valve springs added. I tough about redoing the valve springs and rocker arms, but I after looking at several pictures I feel they are pretty darn accurate, as far as I'm concerned.
October 31, 2023
The kits engine has these brackets "circled in red below" located on the back of the engine, but the Oberursel UR-2 rotary engine did not appear to have these on the back or the front of the casing. I looked over many photos of both the Oberursel UR-2 rotary engine and LeRhone engines, neither had these brackets. Not sure why they were molded into the kit but I will remove them to make the engine a little more accurate. The picture below is of a LeRhone 80HP motor.
The image below is of an original LeRhone engine and it's pretty clear the pushrod brackets were never on the engine.
Here is a picture of the part prior to modification with the brackets.
The rear engine case with the brackets removed and the exhaust attachment points sanded down a little, they were a little thick.
Another modification I'm working on is the milled out area next to the cylinders. These are a pretty dominate feature on the engine and they really need to be there.
As you can see here, they are not molded into the casing. Not sure how all fix this issue yet, but I really feel it needs the added detail.
The other item I will replace is the brass pushrods supplied with the kit. They look to thick and the plastic fittings on each end are not scale at all, they just added them for a means to attach the brass pushrods to the casing.
I've decided on 1/16" steel wire polished to a shine to replace the brass ones. These look more correct for the scale. I'm going to drill a small hole into the rocker arm and slide the steel rod through down to the case. These will be installed after painting so they appear more realistic to the eye.
November 5, 2023
Things are progressing on the engine. I noticed the other night that I had forgotten to add the valve stem push rod. After some figuring I did manage to get them into each cylinder.
I used Milliput to add the milled out area's on the case detail. This was a tidiest little task indeed, should pretty convincing once painted. Once I finished the back of the engine, I took a break and started working on how to make the push rod inlets. the photo is showing the Milliput prior to any clean up or final prep work before painting.
Made a jig and cut 9 inlets our of plastic tubing.
Once these were glued into place, I temporally installed the unit to the main case to see how the push rods etc. lined up to the cylinder's.
The push rods enter the lower case at angle as the rod ends up in the center of the case, this did not look right, so back to my resources.
If you look close you can see that the inlets are not dead center of cylinders and the exhaust ports are off center of the milled out case locations as well.
This is what's causing the the push rod to enter the case at an angle.
I removed the positioning pin on the part so I could rotate it. With the case that contains the pushrod inlets rotated a few degrees to the left, everything lined up perfectly.
Just a few items that need to get tweaked and then all start laying some paint and bring this stage of the project to completion.
December 4, 2023
Been sometime since I posted anything, been sick with the
dreaded RSV all of November. I did manage to keep moving forward on the model
at a pretty slow pace. I left off at getting some items buttoned up so I could
start painting. I use Tamiya paints for most of my painting needs. I will use
some Alcad II paints overtop of the Tamiya to try and get the look I’m shooting
for. I would like the motor to look somewhat combat weary but not filthy dirty
in appearance. This will require layering of aluminum paints of various shades.
To get the final look I will utilize pastel chalk and then seal coat the entire
motor with a semi-gloss once I’m happy with it. I did get the engine painted to
its final look on 12/2, so now I’m just finishing up adding the pushrods and
spark plug wires as seen in the pictures below. Next up will be the Spandau machine
guns, looking forward to working on a different aspect of the model!
Getting closer, just started adding the pushrods.
December
9, 2023
I
finished up the Oberursel UR-2 rotary engine for the Triplane today. Feels good to have this
build task completed; now I can move on to the Spandau’s guns. The pushrods
went into place perfectly and look pretty convincing, with that done I started
to install the plug wires. I’m using ASK 0.3 lead wire for the plug wires, took
me three tries to get the wires tp look right. Once that was complete, I applied a
coat of Tamiya Semi-Gloss clear to the motor and will set it aside as it awaits
installation into the Fokker Dr.1.
Ready to install the plug wires with all the pushrods installed.
First plug wire in place, think these should look pretty convincing.
Semi-Clear sprayed on the motor and this phase is done!
.jpg)
.png)
No comments:
Post a Comment