cylinders

Peter, reading through you methodology it seems to be fairly sound. I wouldn't be concerned about the wall thickness, it seems in line with aircraft engine practice of the time. The Gnome Rotary engine, had a wall thickness of 1.5mm. That was a 100hp 9 cylinder, so I guess the forces would be way in excess of anything an ABC would see.

Taken from http://www.pilotfriend.com/aero_engines/aero_soupape.htm

"They were mostly built of forged steel machined to very thin sections for lightness. Each cylinder, for example, began life as a 97-pound nickelsteel bar. When it was completed, it was only 1.5 mm thick and weighed five and one-half pounds"

On the piston debate, I've just been looking at the Honda pistons, and they don't appear to have the right crown geometry. The piston is presumably dictated by the geometry of the cylinder head, the location of the valves and the spark plug location. So to find a modern engine that matches all that seems a long shot. It seems the piston issue is common and only going to get more so. Would it be an idea to manufacture some? With new cylinders, and new pistons, it's almost a new engine!


Anyway, it seems a most interesting project.

Nicholas

hi peter i have received you email but it has vanished somewhere my computer keeps freezing should have a new one tomorrow

I have received a lot of input from many members and the general feeling is that the replacement cylinders must be as close a match to the original Sopwith cylinders as possible. I will finish the Cylinders with a bore of 68mm, which I can either hone or leave as machined. If anyone would like a custom bore please let me know.

As far as the piston options are concerned I have received many varied and interesting comments and I think we should continue the discussion under "Pistons".