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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-3635791@logan.com>
Subject: Re: [FlyRotary] John Downings Tach
Date: Fri, 8 May 2009 16:45:40 +1000
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Bob,
Not like you, having something beat you like that - what about a motorcycle 
tach.
George (down under)

> 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/
>


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