From experience, I believe both Jim and Keith have hit the ball on the head! One problem with the Aster GNR single was the axle pump, the balls were too small and the pump cavitated as Keith explains. Two larger balls from Aster were supplied but I still find it necessary to prime the lines with the hand pump before starting the loco. (the hand pump line runs thru the axle pump valve body) With that simple procedure the pump performance is excellent. Incidentally, the water enters into the bottom of the boiler! Since the axle pump is basically a hydraulic pump I note that with the locos I have: 1/16th and 1/32, the length of the lines vary as do the check valve locations in to the boiler and there appears to be no difference in performance. In nearly all case the water lines descend to the pump and then rise to the boiler. Descending to the pump from the water tank insures the pump is primed. Back pressure to the pump valve body is advisable to properly seat the discharge ball on water intake strokes.
Keith wrote ">anything at all, things like my name etc. is becoming increasingly difficult as time marches on!" Hey Keith! wait 'til yer in yer 80s. Well, I must say, then, at least time doesn't march on, it plods, staggers and gits lost a lot! Er, What was I a-saying? Geoff ----- Original Message ----- >From: "Jim Curry" <[EMAIL PROTECTED]> > >> Royce: >> >> Ball location of 1" sounds ok. A more important consideration is how >much >> travel the ball has in its port area. When I built mine I found it >worked >> most dependably when it traveled 1 ball diameter or less from its >seat. >Hi Jim, & Royce >I need to look through my refernce materials, but for some reason the >formula of the ball lift being 1/3rd of the seat diameter comes to mind, >as the optimal lift figure. Carl Purinton and LBSC did a lot of >experimenting on ball lift dimensions back in the 1930's, and all I need >to do is remember now which place I have the info marked! Remembering >anything at all, things like my name etc. is becomeing increasingly >difficult as time marches on! But I do seem to remember that if the ball >lift is too great, you set up eddy currents in the check body, that keep >the ball from seating properly between strokes of the pump for the >inlet. If the delivery side doesn't close, it wants to draw back the >water it just pumped! Not very efficient! >Keith > >
