Not enough sparks per combustion event :)
 First cost would be lower but one might make it up
 long term with a dual or triple MSD.
 Paul Lamar
 ---------------------------------------------------
 Paul,
 Couldn't the Ford EDIS be fed into an MSD ignition module to
 produce a multi-spark ignition system?
 Mark S.
 Yes but you don't need it. Just three low cost ABS sensors in the
 three rotor case with one just tit on the trigger wheel will do
 the job.
 In Tracy's system if it puts out 3 pulses to fire the LS1 coil
 that can be conditioned to fire 3 MSD systems.
 Paul Lamar
 ---------------------------------------------- Paul,
 Sorry, in my last post I was thinking of an automotive
 application rather than a/c.
 I've been re-reading your information on your 220v inverter multi-
 spark ignition system. That would be a big improvement over the
 single-spark LS1 approach.
 Mark S.

 --------------------------------------------------------------------
 You may have missed it but MSD rated the multi spark at 3000 RPM limit
 with an 8 cylinder, 6000 with a 4 cylinder and 12,000 RPM with
 a 2 cylinder or one cylinder 2 stroke or a one rotor. All firing
 once per rev.

 Quote:
 Dear Sir:
 After conferring with the engineer I transferred you to yesterday,
 I was  opposite of where I needed to be.
 He explained that he actually hooked up a 6A unit, basic CD
 ignition  with no rev. limiter or cylinder select function. On an 8
cylinder
 application the multi-spark reduced to one spark at 3,000rpm.
 When he tested for the 4 cylinder application the multi-spark
 doubled to  6,000.
 He surmised that on a 2 cylinder application, the multi-spark
 would  disappear at double that r 12000 rpm.
 This was on a four stoke application.
 He did say that he wasn't sure about a Wankel application and was
 waiting for a call from you to discuss some issues.
 That engineers name is Rick Bennett, his extension is: 2402
 Sorry for the confusion. I apologize.
 Thanks,
 Rick Jage MSD Tech
 end quote
 --------------------------------------------------------
 My system would work better as the sparks are more widely spaced
 but three MDS units one for each rotor is almost as good.
 http://www.rotaryeng.net/Why-CDI.html
 Paul Lamar
 -----------------------------------------------------------------

 Paul,
 So then, for a 3-rotor, using six individual MSD-6A modules would
 provide  a multi-spark ignition good for up to 12k rpm. As the MSD-
 6A weighs 3 lbs  each, that would be 18 lbs. of added weight not
 counting the coils. I'm  curious if its possible to use one MSD-6A
 per rotor to fire a dual tower
 (wasted spark) coil to fire both the leading and trailing plugs
 on the  same  rotor? Probably not.
 Mark S.
 ------------------------------------------------------
 You got me there Mark. I think Lyn Hanover mentioned that.
 Yes here it is:
 quote:
 "The top pick up for the front housing and the lower pick up for
 the rear housing. Have the MSD drive a double ended MSD (or other
 suitable) coil to fire both plugs at once. No advance curve is
 required. The engine will start and run fine with
 anything from 20 to 27 degrees of advance."
 end of quote.
 -----------------------------------------------------
 That 220 volt power supply weighs only 2 pounds so my system
 would be lighter in weight. Less the coils of course.
 Paul Lamar

 -------------------------------------------------------
 I see that it was Lynn's quote. But reading it a few
 times, it appears that he's describing a wasted spark system. I
 am wondering if one dual-tower coil (fired by an MSD) can fire both
 plugs on the same rotor. That's how I ran my 3-rotor on test stand,
 but didn't have any way to tell if both plugs actually fired
 together or not. I would need a scope to tell for sure.
 Mark S.
 ---------------------------------------------------

 Not wasted spark. Both upper and lower plugs fire
  at the same time but only on the rotor that is ready.
 Paul Lamar
 -------------------------------------------------------
 I trust Lynn's information. If he says it will work, then it will work.

 I could use my triple pickup CAS. (I still need to look around in
 my parts bin for it.) I know it will work for triggering the three
 MSD-6A's because I ran it years ago using three GM ignition modules
 and three GM (Buick) dual tower coils. The only difference here is
 that I would substitute three MSD-6A's for the three GM ignition
 modules. And as Lynn suggests, use three MSD coils.

 Firing only one rotor each, the MSD's shouldn't have any problem
providing
 multiple sparks up to max rpm (7500).

 Mark S.
 --------------------------------------------------------------------
 How well will these coils stand up when they are firing two plugs
 in the  compressed mixture. With two gaps full of air molecules that
 are resistors,  the firing voltage will be higher. In an a/c
 application at cruise, the  continuous load over hours should heat
 the coils up and reduce life  expectancy. In a race car, there is
 short bursts of full throttle and then  Deceleration. This allows
 some cooling.

 Dale Davies
 -------------------------------------------------------------------------
 Good question but the second gen double output coil held up real
 well in AC  use and they can be used with MSD systems. Just the
 ballast resistor burned  out in aircraft use. Actually a cap
 discharge system is easier  on the coils. You can unbolt and
 disconnect them from the 2nd gen igniters  and used them as CD
 coils. No ballast resistors.

 If you can get them on e-bay for a good price snap them up.

 Paul Lamar
 ---------------------------------------------------------------------
 Paul,

 Last week I decided to move ahead with the MSD cap discharge
 ignition idea for my 3-rotor. I purchased three MSD-6A ignition
 modules. The three 6A's will be driving one dual tower coil each
 (one 6A / coil per rotor). The three MSD's will be triggered by a
 custom CAS with one trigger per MSD-6A.  That should give me multi-
 spark to 12,000 rpm. ;-) I've hooked it up on the bench and it looks
 like it will work as intended. Just for clarification, this will not
 be a wasted-spark system. Each dual tower coil will be firing two
 plugs on the same rotor, as Lynn described. Stay tuned...

 Mark S.

 Do the MSD-6A really weigh 3 pounds each? The Mazda 2nd gen coil is
 1.5 pounds.

 Paul Lamar

 I take it that the CD use developed high voltage low current and short
pulse spark that did not heat the coils. It is the current that would heat
them the most.

  Dale Davies

Correct. Some of the power going into the CD system is lost
by the power supply that converts 12 volts to 460 volts.

Paul Lamar


Mark,

This sounds similar to the approach I am using except I'll use the CAS
position for driving something else.  My biggest concern has always been
plug life. Multiple firing the plugs may require switching to a cooler?
plug.

Doug in Japan

Do that with caution Doug. Plugs have failed with parts broken off.
The electrical current the plug passes is reduced with CD systems and
history has shown they last longer. Instead of one long single
surge of current multiple shorter surges are passed.

Currently with inductive systems plugs last about 50 hours if
100LL is used and about 100 hours if unleaded auto fuel is used.
The RX8 has iridium plugs claimed to last 100K miles in the car.
I have no data on aircraft use.

BTW EAA magazine had an article on the new revised Continental
O-200 for LSA and the compression ratio is now up to 8.5:1 so for that
and other metallurgical reasons it requires 100LL. The the crank webs
had to be beefed up and other detail structural changes made but weight was
saved in the accessories, oil pan design and by drilling out the crank.
It is still around 220 pounds with starter and mags. This is the main
one rotor target.

Paul Lamar



Where did you get 220lbs?  The data I've seen says it's 199lbs with
starter, alternator and mags, but no exhaust.

The TCDS says the -D is 14lbs lighter than the -A - 176lbs vs 190lbs.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/7b2314bdafb505b3862574e50073065f/$FILE/E-252.pdf

Based on the accessories listed, I'd say those weights are without
starter and alternator, but with mags and carb.  Getting starter and
alternator for 24lbs seems like a reasonable goal.  The earlier
O-200's seemed to hit 225 with starter and alternator, based on
discussions from the EZ group and the old Canard Pusher newsletters.
Rutan didn't want to see starters and alternators on the Varieze as
they pushed the vibrating mass above 200lbs.  After the O-200 became
more rare and people were putting O-235's on the Varieze, Rutan said
215lbs was the absolute max for the Varieze.  Of course, a few people
put O-290's and O-320's on the Varieze - Bill James and Martin Skiby
come to mind.
.
I'd bet $10 that Continental designed the O200-D with unleaded avgas
in mind - 94UL or whatever it's going to end up being.  They are
testing the IO-550 powered Cirrus with 94UL and aren't reporting any
problems.

Anyway, lighter is better for the single rotor.  Little airplanes are
more sensitive to the onesie-twosie lb weight increase.


Matt-

I am just going on the article on page 94 EAA Jan mag.
"The A and the B models could weigh as much as 225 pounds."

Where did you read 199 pounds. It is really hard to get
25 pounds out. The carb weighs a few pounds too.

It says in the article 100LL leaded gas is needed and no
mention of 95UL.

It is really hard to nail all this down unless somebody
weighs one.

Paul Lamar.