Gallery

Cliff Ward, Cary, North Carolina cd_ward@nc.rr.com

Satra M-5, 5 Cylinder Radial Engine

6/162007

This project started as a “custom kit” of partially machined castings from Bruce Satra. Since I am still a novice machinist, Bruce agreed to do the difficult machining on the crankcase and head castings, and saved the more straightforward tasks for me to machine. I have always wanted to learn more about how radial engines work, and for me building the engine seemed the best way to accomplish this. I also wanted to have a good chance at making a good running engine, so having Bruce handle the more difficult machining jobs allowed me to get this engine built while my machining skills are developing.

The photo of the set-up in my Benchmaster mill is where I am finishing up the internal bearing carrier….this was a rather more involved part than I first thought, as it has to hold to three decimal places in several areas (OD., ID, and a raised area) in the lathe and then 12 holes are to be drilled on a radial circle (the Benchmaster mill photo)….I made a special jig to hold it in my rotary table for these holes so the aluminum part could be held steady without deforming the piece. I imagine there must be at least 50 easier ways a more experienced machinist might have done the job. Once complete the bearing carrier was a gentle press fit in the crankcase.

At the current time I am fitting each head to it’s respective location on the crankcase (2^nd photo). In order to provide clearance over the pistons I am shaving portions of each piston dome…it’s a bit of a of tedious file, trial, fit process. But things are just about finished with that portion so I should have it buttoned up pretty soon.

Next come assembling the distributor, and making an exhaust ring. After that I should be ready to fit it all on a wood stand for first run.