Mailing List flyrotary@lancaironline.net Message #46046
From: Bob White <bob@bob-white.com>
Subject: John Downings Tach
Date: Thu, 7 May 2009 22:13:53 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
John is using a standard tach that is normally connected to a
distributor/coil ignition system.  The straight 12V pulse used for the
LS1 coils wouldn't activate it.  I built an interface for him that
involved taking that pulse as an input and generating a shorter
constant pulse width output.  I modified the tach to trigger on the
lower voltage signal, and adjusted the scale factor to read correctly
with one pulse/rev.  As John reported, it worked for about 0.8 hours,
then quit.  He is sending everything back to me so that I can find out
where the problem is.  I would like to find a tach solution that John
can use without modifying anything.  The parameters are he has a 2 1/16
inch mounting hole, the tach needs to read correctly with 1 pulse/rev
(would be the same as a two cylinder piston engine with coil and
distributor), should trigger directly on a 12V pulse.

I've found tachs on the web that mention working with distributorless
or electronic systems, but none of them were the 2 1/16 inch type.  I
found a converter, the MSD 8913, but on the Summit Racing catalog it
specifically says it won't work with the LS-1 system.  It work by
sensing the current pulses to the 12V power lead on the coil.  I don't
know why it wouldn't work with an LS-1 coil, but it doesn't seem like a
good investment when the LS-1 is specifically mentioned as not working.

Can anyone recommend a tach solution that John can use with his LS-1
Coil rotary engine combination?

On another topic, John has the only system I've heard of that has the
capability to run on either EFI or a carburettor.  John posted a
picture of his Tailwind a few days ago.  It's a very good picture but
considering the redundancy of the EFI/carb system, I felt that the
picture was lacking.  I submit this edited version as being more
indicative of John's desire for uncompromised safety.

Bob W.

--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://roblinstores.com/
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster