There is another reason (maybe not in most conventional aircraft magneto systems) also that used to be used by the automotive boys with dual points and a coil splitter.
By setting the timing slightly out of phase and running both points simultaneously, the length of the effective spark can be increased. The phase shift was achieved by offsetting the point mounting dowells/holes by a few degrees on the distributor plate. A less elegant way is to alter the point gap to vary the dwell but with conventional coils there is a certain time needed for the coil to energise which limits the time the points can be open and the dwell extended. I have heard of one magneto in aircraft being retarded a little to make starting a little easier but not sure if this is common. John Martindale 29 Jane Circuit Toormina NSW 2452 Australia ph:61 2 6658 4767 m:0403 432179 email:john_martindale at bigpond.com web site: -----Original Message----- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Flesner via KRnet Sent: Monday, 14 December 2015 2:36 PM To: KRnet Cc: Flesner Subject: Re: KR> Dual ignition At 10:48 PM 12/12/2015, you wrote: >Concerning Dual ignition: I also get 100 rpm more with both ignitions on. +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ The reason for an rpm increase is because two plugs firing in the cylinder gives a better flame front and thus a faster burn. ....snip ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2016.0.7294 / Virus Database: 4489/11174 - Release Date: 12/14/15
