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A dimension is a distance. Inches or millimeters don't matter since there is an exact conversion. By definition, there are 25.4 mm in 1 in., so conversion is simple.
If so, the answer is that radials are usually designed around a master rod. The other rods connect to the master rod and they do not have quite the same stroke as the master rod since they are connected ina circle around the exterior of teh master rod.
Hallo.
Cylinder dimensions for Deerhound I in "British Piston Aero-Engines and Their Aircraft" (by Alec Lumsden):
Bore: 5.26 in. (135 mm)
Stroke: 4.95 in. (127 mm)
Swept Volume: 2259.75 cu. in. (38.19 litre)
But...
5.26 in. is (circa) 133.6 mm
4.95 in. is 125.73 mm
Vol. (circa) 2259 cu.in. OR 37.0 litre
OR
135 mm is 5.315 in.
127 mm is 5.0 in.
Vol. 2330 cu. in. OR 38.175 litre
Deerhound cylinder dimension in metric units? Or British (imperial) units? (Previous Armstrong Siddeley engines is in imperial units.)
Thank You.
I not known stroke variations (on connecting rods), but most probably not too high. As i see russian "remont manual" for M-82FN engine (or Shvetsov ASh-82FN, Швецов АШ-82ФН), its piston strokes varied (bore × stroke is usually as 155.5 mm × 155 mm):According to my handy-dandy calculator, the bore and stroke info breaks out as follows:
Deerhound - 135 mm (5.315 in) bore, 127 mm (5.000 in) stroke, 38.175 L (2,329.599 cu in) total displacement (not accounting for individual cylinder stroke variance).
Deerhound II - 140 mm (5.512 in) bore, 127 mm (5.000 in) stroke, 41.055 L (2,505.347 cu in) total displacement (not accounting for individual cylinder stroke variance).
Mea Culpa! Books from RRHT is great sources, but in my library is only few — and all only for RR engines (most for pistons, only Dart between them).In "Parkside: Armstrong Siddeley to Rolls-Royce 1939 - 1994" (Rolls-Royce Heritage Trust Historical Series No 39) by Roy Lawton,
For me not too clear for british firms (but only few, two, or three?) at this times "switched" to metric, but Armstrong Siddeley not one, also de Havilland (piston engines as Gipsy Queen / Six and Gipsy King / Twelve):In 1932, Armstrong Siddeley began to design a new series of engines that were very different than their previous engines. The old engines were named after felines (cats), so they decided to name the new engines after canines (dogs). The new series used metric. I do not know why Armstrong Siddeley switched and it seems no one else does either.