Message-ID: <3C8640F5.1010702@regandesigns.com>
Date: Wed, 06 Mar 2002 08:16:53 -0800
From: Brent Regan <Brent@regandesigns.com>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.4) Gecko/20011019 Netscape6/6.2
MIME-Version: 1.0
To: Lancair List <lancair.list@olsusa.com>
Subject: Re: DQ
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Reply-To: lancair.list@olsusa.com

          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
Charlie discovered that Impulse Couplings are trouble waiting to happen. 
Why you would have impulse couplings on both mags when only one is ON 
during start is a mystery. I don't know about Charlie's mags but on my 
airplane (Bendex S-1200 mags) there is no impulse coupling but the left 
mag does have a second set of breaker points that are "retarded" to 
about 5 DBTDC. I have also wired in a Starter Vibrator whose function is 
to provide an alternating (pulsating) current to the magneto's primary 
winding during starting. During starting the retard points and starter 
vibrator are used to deliver multiple  sparks beginning at 5 DBTDC and 
continuing through TDC. This system is also known as "shower of sparks" 
and has been 100% effective in my plane. The bad news is that you can't 
hand prop a start, not that I would ever try on a 540. The good news is 
that prop is less dangerous when the plane is parked.

If I were Charlie I would be asking why there is a second impulse 
coupled magneto and who put it there (I doubt it is in the parts list 
for that engine). I would seem that the problem was caused by a part 
that wasn't supposed to be there. I would be asking the guy that put it 
there what he is going to do about it. I would also be considering 
getting rid of the left impulse coupling as well.

Regards

Brent Regan


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML website:   http://members.olsusa.com/mkaye/maillist.html
LML Builders' Bookstore:   http://www.buildersbooks.com/lancair
Please remember that purchases from the Builders' Bookstore
assist with the management of the LML.

Please send your photos and drawings to marvkaye@olsusa.com.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>