Virtual Capstan

[Richard Brekne]

Ron and others.

Ok... here are some measurements, and some of my own Stanwood based leverage
analysis.

First.. the distances and weights of parts.

Hammer SW is 11.7 grams
KR (Stanwood) 0.51 for capstan, 0.45 for key magnet.
FW 30,2
Whippen radius Weight
    no mag 16.7 grams
    with one mag and assembly taken at whippen cushion 19.4 grams
    with one mag and assembly taken at mag 15.6 grams.
Whippen mag assembly dead weight 2 grams.

BW no whippen mag assembly mounted -- 40 grams
BW mag at 12 mm -- 38 grams
BW mag at 8 mm -- 34.5 grams
BW mag at 6 mm -- 30.5 grams
BW magnets touching capstan turned down -- 21.5 grams

Key front to center key across the top of the key 260 mm
Mid point of capstan to center key across the top 126 mm
Mid point of magnet to center key across the top 108 mm
Key depth (top to bottom)  22 mm.
Hammershank center to middle of hammer core straight down the shank 131 mm
Hammershank center to middle of knuckle straight down the shank 17.3mm
Knuckle diameter 11 mm
Whippen center to balance rail pin bottom of key 202 mm
Whippen center to capstan top middle (half blow) 71 mm
Whippen center to magnets midpoint of seperation (half blow) 87 mm
Whippen center to capstan normal intersect straight accross the whippens lower arm
66 mm
Whippen center to magnet normal intersect straight across the whippens lower arm 84
mm
Whippen cushion depth 23 mm.
Whippen center to 1 mm forward of back edge of jack top 93 mm.
Hammer

--------------
All this yeilds pretty much what I expect from the secondary capstan perspective I
have. The capstan yeilds an action ratio taken with Stanwoods method of 5.27,
measured distance wise the way I do, 5.38 and at the point where the magnets are
3.8 (Stanwood) and 3.7 (my distance measurements)

Ratios for different Magnet seperation distances

SWR at 12 mm 5.23
SWR at 8 mm 4.92
SWR at 6 mm 4.59

I will be interested in seeing this explained in the 2nd class lever perspective.

Cheers

RicB

--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html