Saturn wiper motors

[Joe Sommer <anvilus9-at-adelphia.net>]

Geoff and Brian,

At 11:34 AM 11/30/2002 -0500, you wrote:
>Awile ago I calculated 56rpm turning a 4" drive sprocket is about 3 mph.
>The drive configuration of Tiger 007 has been updated since the last pics 
>were taken.
>Now that I have a digital camera an update pic should be forthcoming.
>
>Two words of advice:
>The drive spline is unique to the arm and will not bolt-up to anything 
>else. I had to weld the drive arm to a pipe flange and bolt the chain 
>drive sprocket to that. Bringing me to point two. Bicycle chain drives are 
>a bit fragile for this application. Especially any of the hi-pro racing 
>stuff that is light weight. Toy store bike parts are probably a bit better 
>because of the heaviness. I an considering using a double chain for the drive.
>Knowing then what I do now I might of considered going belt drive. Not to 
>say it might  have it's own set of problems.

1)  The end of the Saturn wiper motor shaft is an
M8-1.25 metric thread.  I bought a long M8 coupling
nut from McMaster-Carr and drilled out one end for
a 1/2 inch shaft.  I then drilled and tapped set screws
laterally into each end of the coupling nut to retain
the nut on the Saturn shaft and retain the 1/2 inch
shaft in the nut.  I mounted the Saturn motors on two
internal vertical bulkheads parallel to the sidewalls of
the lower hull and ran the drive shafts from the
coupling nuts out to the drive sprockets through 1/2
inch flange mount bearings in the sidewalls of the hull.
This gives direct drive from the Saturn motors to the
drive sprockets similar to the photo for Frank's Tiger
T001 using kiddie car motors.  A full-size side view is
shown in file Saturn_motor_mount.doc     at
http://users.adelphia.net/~anvilus9/

2)  My Saturn wiper motors run at about 100 rpm for
12 VDC battery power under NO LOAD.  My 12T drive
sprocket has 4.2 inch OD and drives 1.07 inch pitch
conveyor chain.  This concomitantly moves 1.07 feet
of track per revolution and provides 107 feet per minute
under no load at 100 rpm.  I converted 107 feet/minute to
1.22 mph, hence my question about 1 mph top speed.

Brian, you may wish to check your speed calculation
that 56 rpm turning a 4 inch diameter drive sprocket
provides 3 mph.  I get 0.666 mph (unless your chains
provide a speed increase of 4.5 to 1).

3)  Based on Frank's recommendation for 3 to 4 mph,
I do not recommend the Saturn wiper motor for direct drive.
I have scrapped my Saturn motor plans and I am going
to Lowes to buy two Delta 12V drills with 330 in-lb
torque at 400 rpm.  The Saturn motors may be good
for turret rotation at 56 rpm (~1 revolution per second).

Joe


Joe Sommer
2378 Nantucket Circle, State College, PA 16803
814.234.4773     anvilus9-at-adelphia.net
http://users.adelphia.net/~anvilus9/