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Date: Fri, 8 May 2009 10:03:22 -0600
From: Bob White <bob@bob-white.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: John Downings Tach
Message-Id: <20090508100322.0035d7de.bob@bob-white.com>
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You are right George.  If I could go to John's to work on it I'm sure
we could get it sorted out.  Being far away and John close to doing his
inspection I would sure like to find a good reliable solution.

Bob W.

On Fri, 8 May 2009 16:45:40 +1000
"George Lendich" <lendich@aanet.com.au> wrote:

> 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/
> >
> 
> 
> --------------------------------------------------------------------------------
> 
> 
> > --
> > Homepage:  http://www.flyrotary.com/
> > Archive and UnSub: 
> > http://mail.lancaironline.net:81/lists/flyrotary/List.html
> > 
> 
> 
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html


-- 
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/