Mr. Abraham, Post#14
[QUOTE][The degree of impulse coupling retard is directly proportional to crank speed./QUOTE]
Sir, this is a somewhat ambiguous statement...I would suggest that it's FIXED according to crank -speed.
for those who are less into the technicalities,-
The flame-propagation is, to all intents, at a constant speed. the advance is given to ensure the charge is burning BEFORE the piston reaches TDC , but expands AFTER tdc....once an impulse-coupled mag is set, it will always "release" at the same timing-point...flicking the Mag smartly as the spring is "tripped" each impulse-coupling has an "operating angle "between arresting mag-rotation and release......the salient point is that at slower cranking-speeds, there is less rotation and therefore the piston is further down the bore FOR A GIVEN AMOUNT OF TIME......faster crank= piston quicker to reach TDC = fire needs to get lit earlier. (otherwise gas expands before piston/crank goes over top,stops it, and pushes it back AKA "kickback" )
so, a given coupling will always give the same retard on impulse,irrespective of speed(as long as it's below the point at which the impulse disengages)
My very limited experience DOES extend to Armstrong-starting a vintage Aeronca....I was taught to "crease" no more than the first joint of the index -finger over the prop leading edge and NOT hook it....free hand behind back firm ,straight-arm pull and follow-through....great fun and I still have all my fingers
