Onager - First Components Delivered

[D B Campbell]

Hmm. I'm using the technical treatise by Eric Marsden. Here' he suggests the vertical stop is better as the inclined stop resulted in frequent breaking of the arm.

As far as I recall, Marsden never mentions the forward-sloping buffer suggested by De Reffye. He basically compared Schramm's backward-sloping buffer with Payne-Gallwey's vertical buffer, and preferred the latter.

I don't remember anything about Marsden experiencing arm breakages. What's the page ref?

It's true that Schramm initially had problems because he tried to stop the arm too soon -- after it had swung through only about 37º (the same as his ballista's arms!) -- and had to increase the angle of his buffer. But it still sloped backwards.

Wasn't it Payne-Gallwey who had all the arm breakages? (Also, iirc, he couldn't secure a backward-sloping buffer firmly enough to stop the arm thrusting it away from the frame -- surely a fault in his joinery skills rather than in Schramm's backward-sloping buffer design.)

The De Reffye buffer, on the other hand, slopes forwards. That's the beauty of his underrated design. The longer the swing, the better. (Prefiguring the trebuchet, where the arm has maximum swing!)

Of course, you then have the problem of pulling the arm back again -- I guess you'd need to employ a combination of pushing and pulling. I think that's why the Payne-Gallwey design has proved so popular -- it's dead easy to operate. But is it accurate? (btw I don't remember Payne-Gallwey ever arguing the case -- he simply presented it as a fait accompli. Didn't he?)