I didn't like the vacuum formed radial engine facade that was included with my Legacy Aviation Muscle Coupe, so I searched online and finally found a model of a 7 cylinder radial engine that I resized it to work on the model. It's labeled as a C30 engine from an autogyro from Europe, so I know its not scale, but it sure looks good in the cowling. I do not know who original modeller is, but I would like to thank them. The original .stl files included the full cylinder heads and an exhaust ring, but they wouldn't fit on my model so I excluded them in this posting.
Print 1 mount, 1 crankcase, and 7 cylinder fronts.
Printed solid as the models are just shells anyway.
Use your favorite cement to glue the cylinders to the crankcase. I used some ABS from my local hobby store to make the pushrod covers and glued them in as well. I had to resize the holes where they fit with a small drill bit before they would fit. I painted everything in Tamiya Gunmetal polycarbonate spray, then misted some Tamiya Bright Gunmetal polycarbonate spray to pick up some highlights. The pushrod covers were brush painted with Tamiya Chrome Aluminum acrylic.
Fit the mount into the crankcase and drill some holes between the cylinders to hold the engine to the model. I used some 2.5-3mm socket head machine screws 6mm long. Doing this before mounting anything to the model is easier than with it mounted.
The mount goes behind the motor "X" mount using the original 4mm screws. Longer screws may be wanted, but the screws I got with the model or motor were long enough and just about fill the original T-nuts on the firewall. The motor wires will pass through one of the holes on the side of the mount. Add the dummy motor and screws.
Ready to fly!