daiku,
Shame, shame. Denigrating hammerbeams is not your style. Properly designed and executed they last and last and last. And the tendency to bulge along the axes of the timbers is a myth spawned by bad design and execution. Yes, they can deliver the net forces straight down (or vertical if you prefer).
The king post is probably stronger than the calculations for a give species yield. A house circa 1750 in Fredericksburg, VA has what visually seem to be "small in timber cross section" king post trusses. Yet it holds up a very heavy slate roof (the original cover was wooden shakes). The newer pavillion at Ferry Farm, also Fredericksburg, has massive timbers in it's king post trusses. See the article here on the TFG website.
deralte (avid hammerbeam fan)
