Any of you EE types have any suggestions for making a cheap tach
that will work with mags? Preferably digital.

Try RPM from Sound.
http://www.wwnet.net/~rscott/rpmsound.html

I went to the hobby shop and bought an optical tach for $37.95. 
Works great.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org