Hi Keith,
just looking at the OS Max web site concerning discontinued engines and it gives most of the older 60H motors as being over 20oz without muffler, sooo add the muffler and the extra beef for the bigger capacity and that's where my wild guess came from.
But If Charles says it weighs in at 18.3 then that's what it is but consider that the OS 80H is then lighter than a the LA 65 at 18.9oz and on par with the 61 FP and I find that odd when considering double ball races on the crank, needle rollers on the rod and the rear intake setup.
Thanks.
Well, the Peter Chinn articles on the OS 60H (rear drum) published in Model Airplane News (Jul 67 and Dec 69) lists the the OS 60 rear drum se at 14.9 oz. I have four of these within a few tenths of an oz from the Peter Chinn published numbers except the one that has no exhaust restricter (coupled with the throttle) comes in at 14.4 oz. These engines ran smooth and have a very effective throttle. They carried a big prop on a heavy CL scale plane and had all the power that I needed. Very dependable. I would not hesitate using them on any suitable sized scale model for CL. Hand starting was no problem with a cold engine and after it was broken in would start easily when warm.
I am not sure, but I would suspect that the front intake 60 versions of these engines weighed more than the rear drum versions.
I have no experience with the 80 version, but do know that it was used in the RC scale arena in its time. No, these engines do not have the power of more modern similar sized schnuerle engines, but for scale operations, they worked just fine.
I would be interested on what Dennis Lipsett based his "anemic" comment.
Keith