The cylinders
Terry who has already built this engine suggested lengthening the cylinders, to be more similar to the original.
In this drawing the black part at the top is the elongated part compared to the Draw Tech project ,of course I also had to lengthen the connecting rods by the same...
The assembled crankshaft, with an external alignment cylinder during the finishing turning of the shafts .
first step, right side
second step , left side
Final check of the coaxiality of the 2 shafts, without bearings and with bearings
Max error detected 0.03 mm
For the connecting rods I provided bronze bushings, mechanically the needle bearing are better, they have less friction, but the bushings are simpler and more robust.
the 2 flywheel shafts have an allowance of 0.5 mm, when they are assembled with the flywhee , connecting rods and the pin , I will do a final turning to ensure alignment and concentricity .
The assembly was done with a press.
CNC turning of the connecting rod pin
the defective pins, 5...
The crankshaft
My Knucklehead engine is larger than the Draw Tech project, the diameter of my piston is 36mm compared to 27 mm, 1.33 larger , so everything will be larger than the photos of the components that you have already seen in other constructions. The total displacement of the engine...
To make aluminum castings the first step is the 3D drawing of the finished part, then I eliminate all the holes and machining, add the allowance in the milled or turned areas, add an increase that takes into account the aluminum shrinkage .
Finished right crankcase
drawing for casting mold...
The cover are 3D printed, plastic (PLA) .
2 pieces glued together and painted, I had thought about making aluminum castings, too much work, in 2 nights the printer made all 6 pieces . The drawing took more time.
Yes it is a petrol tank, even if it looks like an old aqueduct tank ...
After seeing the construction done by Mayhugh, I also decided to build this interesting engine in a slightly larger scale.
The pistons of my engine will be 36 mm instead of 1.063 inch (27mm) and everything else will consequently be increased by the same proportion.
I have followed and studied...
No, a propeller is dangerous, the engine would still need some aesthetic improvements ,but I'm saturated, I won't touch it again
The next engine will be with 2 cylinders maximum.