Paul,
   How about a dual ignition systems?  Assume coil-on-plugs design
  and that we would use a two stroke marine engine magneto and
  coils incorporated into the starter gear or torsion plate area
  of the housing.  Also assume we would have  capacitor driven
  ignition modules like the new solid state digital programmable
  MSD, 6AL-2.  Check them out.  Small and compact.  One for each
  rotor.
   First some givens about our rotary engines with the single
  leading plug:  The engine doesn't run very well on trailing
  plugs alone, as quite a lot of the fuel goes out the exhaust
                  and
  is burned in the exhaust system.  Said another way, with a two
  rotor engine and a leading plug fouled, the exhaust system may
  well overheat, or the engine would run rough enough that we
  would want to shut it down after a short time.  That means the
  Achilles heel of the Mazda rotary is the leading plug.   As
  quite a few members have pointed out though, a spark plug is
  pretty basic technology.  Yes I agree  but I also can't count
  the number of times I have had them crap out on a  2 stroke oil
  burning engines.  Prudence would dictate changing them quite
  regularly since it is a critical point of failure or beg Mazda
  to cast us up some two bung leading plug housings.
   Conversely if the trailing plugs fail the engine power only
  reduces about 3% if that.  So with a good leading plug and a
  magneto system,  the engine would continue to operate just fine.
  BSFC will be a little off but we won't get our feet wet and the
  plane can continue on for many many hours.
   OK we can all agree that  a magneto is basic technology and
  very fail-safe.  The magneto fires when a magnet passes by
  coils set 180 degree  (20Bs would need three spaced at 120
  degrees) apart.   These coils could be wound to produce 300
  volts.  Timing can be fixed  for a cruise rpm.
   Now for the plus alpha.  The MSD ignition devices can be
  programed to fire the leading (and trailing) plugs many times
  and at moments when the magneto isn't doing that.   Each MSD
  power pack could  get its signal to prepare for  a firing
  sequence from the magneto or modified coil voltage pulse. Since
  the MSD devices have intelligence they can vary the timing with
  rpms. and other inputs received from sensors or even a
  MEGASQUIRT engine control board.
   The question is,  How do we isolate the MSD power from the
  magneto power because they are both hooked up to the same coil?
  Diodes are the easy answer but I wonder if that is a robust
  solution?  In the scenario above  power unit could be charging
  the leading plug coil.
   A FET switch  might be an answer but the fail safe would have
  to allow the magneto to continue firing the leading plug coil
   FETs on the two MSD outputs to the leading and trailing plugs
  would allow split timing if necessary at the higher rpms.  For
  instance the magneto fires the first burst on the leading plug,
  followed immediately by two stronger pulses from the MSD
  Capacitor while perhaps a third pulse from the MSD is directed
  only to the trailing plug.
   Your thoughts?
   Doug in Japan
  I think you are making a mountain out of a mole hill here Doug.
  A phenomena call sag happens when the plugs get to be about 50
  hours old or so.  Minor loss of power.
   The solution is put in new plugs on a regular basis. The plugs
  catch hell in a rotary as they spark twice as often as a 4
  cycle piston engine.  The same as a two stroke.  Now this has
  been reported with inductive type ignition only but as far as
  I know nobody is using a CD system in a flying aircraft.  CD
  systems have a proven track record of making plugs last longer
  in piston engines.
   No telling what the CD spark plug life would be in a rotary
  until we get some good data.  The MSD ignition apparently only
  fires more than once up to some RPM which I know not.  I have
  talked to their engineers about it and they don't seem to
  understand the rotary so they cannot give me a good answer.
  One MSD system per plug would give a lot of redundancy.
  We don't have any data running on trailing plugs alone for a
period of time so it is hard to say what will happen.  Ignition
failures of any kind are rather rare with the possible exception
f 2nd gen igniter ballast resistors which can be traced to
continuous high RPM use.  The wattage rating of these resistors
just be increased.  Tracy also had problems with early Corvette
oils over heating but I suspect that was caused by excessive
well and the fact they were being triggered twice as often.
ne unknown is the charging coil in an outboard motor may not be
ble to charge more than one capacitor at a time so the out board
type ignition system may require two magnets, two capacitors and
two charging coils per rotor for firing both leading and trailing
oils.  Some experiments need to be made to check and see if this
s true.  You will also need outboard type CD coils as RX8 or
Corvette coils per plug will not work with CD systems.  The
thing about 2 cycle outboard coils is they are designed to run
t high RPM and CD systems are actually easier on coils.  They
become mere pulse transformers and not a device to store energy.
n that case they should be far more reliable

   You will also need outboard type CD coils as RX8 or Corvette
  coils per plug  will not work with CD systems.
   The thing about 2 cycle outboard coils is they are designed
  to run at high RPM and CD systems are actually easier on coils.
  They become mere pulse transformers and not a device to
  store energy. In that case they should be far more reliable
   Paul Lamar
   Hello Paul,
   Attached please find the wiring diagram for a 1977 V4 2 cycle 85
  HP outboard.  I do believe the stator and circuitry is more
  complex than the application we are looking for due in part that
  it is working 4 cylinders instead of two.  If perhaps someone
  had a wiring diagram of a 2 cylinder 2cycle outboard it would be
  even better.
   With regards to the throat diameter of the carbs I was
  considering, I was going to use Tracy's estimate of 1 square
  inch per 50 horsepower.  Is that in the ball park or should I go
  larger?  I have not thought about a P-Port yet as I'm still
  learning and the thought of taking a grinder to the engine is,
  at this point, beyond my ability.

   Regards,
  FranklinHello Paul,
   Attached please find the wiring diagram for a 1977 V4 2 cycle 85
  HP outboard.  I do believe the stator and circuitry is more
  complex than the application we are looking for due in part that
  it is working 4 cylinders instead of two.  If perhaps someone
  had a wiring diagram of a 2 cylinder 2cycle outboard it would be
  even better.
   With regards to the throat diameter of the carbs I was
  considering, I was going to use Tracy's estimate of 1 square
  inch per 50 horsepower.  Is that in the ball park or should I go
  larger?  I have not thought about a P-Port yet as I'm still
  learning and the thought of taking a grinder to the engine is,
  at this point, beyond my ability.

  Regards,
  Franklin

  Nothing was attached Franklin. Try again.
   1 square inch is on the small side for 50 HP. 1 square inch
  is more like 45 HP
   Jeff can do the p-port thing for you.
  jeff.doddridge@gmail.com
   A lot easier than making a manifold however you must
  be willing to disassemble and reassemble your engine.
  Mazdatrix will also build a P-port engine for you with
  Jeff's modified p-port rotor housings.
   Since you are using carbs you won't need the slide throttle.
   Read this. http://www.rotaryeng.net/intake.html
   If you still want to use a side port a lot depends on how
  much room you have under the cowl when building manifolds.
  What kind of airplane are you building?
   Is your engine a 4 port or six port?
  Are you good at tig welding aluminum? Steel welding?
  Steel tubing is the easiest to use as the welding skills
  required are minimal.
   Here is a trick for the transition of round tubing
  to oval intake ports. Don't try to flatten a round
  tube. The area will be much reduced which will seriously
  affect the HP you get. We have been all over this in years
  past. A lot of people have been disappointed in the results
  when building side port manifolds.
   Paul Lamar
   Let me try the attachment again.

  Regards,
  Franklin

  There seems to be enough parts for a two rotor but they
  must be rearranged. I am not sure as there is no picture of
  the flywheel showing the position of the charging coils
  and firing coils. Do you have  a digital camera or a cellphone
  with camera?

  BTW I just found a source for magnets. This is a major
  breakthrough for us.
   http://www.maxrules.com/fixomccdi11.html#MAGNET
   I can now go wild designing a magnet holder which is the key
  to the whole works.
   Paul Lamar
   Attached are pictures of the flywheel from the Johnson.  As you
  can see there are sets of magnets embedded into the flywheel and
  then machined smooth.  There are 6 sets of magnets or 12 magnets
  all together.  I'm not certain but I do believe that the sets
  are opposite in polarity.  I'm fairly certain I read that
  somewhere.
   I'm planning on building an aerocanard and I'm trying to keep it
  as simple as possible.  Don't believe I will be able to do the
  gravity feed fuel system, so I'll have to go redundant on the
  low pressure fuel pumps.
   Franklin Canosa
   Lots of magnets in there. I think I have found a picture of
  what goes with it which I included. Do those look familiar?
  The two light colored coils are the charging coils for the
  CD ignition. The other two are the generator coils.
   The big challenge now is making a light weight holder for all
  those magnets that will fit the e-shaft. Do you have a friend
  with a lathe? You will get an alternator out of the deal.
   Paul Lamar

  Paul,
   Yes those are part of the CD system.  The blue ring device is the
  'spark advance mechanism' that we can probalby do without as you
  suggested we just time the engine to 22 BTDC.  The stator is
  correct and you are correct (I believe) about the different coil
  purposes.
   I don't have direct access to a lathe, but would be willing to
  send down the parts from my old outboard for experimentation
  purposes.  I still have the stator, flywheel, a couple of good
  coils and perhaps even the power pack.  I was going to try and
  sell them on ebay, but I would probably get 10 bucks for the lot,
  and this is a far more fun and useful application of the parts.
   Let me know your thoughts.
   Franklin

  I would like to take a close look at that flywheel.
  Most of the other parts are interchangeably or can be bought
  used or new.
   I would like to put it in a lathe can cut it down
  to drastically cut the weight and then make an aluminum
  hub for it to fit the flange on the e-shaft. The flywheel
  aspects of it are not needed and in fact it is not good
  to add rotational inertia to the front end of the e-shaft.
   This. I think, is the key to making this system practical.
   With the flywheel I have all I need do is drill out
  the rivets to remove the magnets. I can then mount
  them in an aluminum hub.
   Paul Lamar

  Paul it may be simpler than that. Machine the outboard flywheel
  to fit under
  the damper, machine it lite and use as is. a stupid suggestion by
  milo!
   I'll investigate that option shortly. I have one of Tracy's
  dampers sitting right here.
   -------------------------------
  Here is what I have so far. I just had an idea this morning
  on how to make this a bit cheaper and better.
   If I chuck the front hub with
  the bolted on pulley in the lathe I can take an small internal
  cut out out of the steel pulley to insure it is concentric.
  Then press in something that looks like this.
  The groove will be filled with uni carbon to cut
  the rotational inertia and increase the burst strength.
  Important at 7500 RPM.
   Paul Lamar

Paul
  "More than one way to skin a cat."  BTW, historically that phrase
was about cat fish not the long felines.
  Generators or magnetos coils work in the radial plane like most
alternators and the featured motor boat stators as you have
posted.   Another way to do it is counter sink circular magnets
into an aluminum starter gear or perhaps Tracy's Al. flex plate
and place the coils pointing in the axial axis.   Coils and
magnets can be mounted on either side (or both) the flex plate/
starter gear in a circular pattern.
   However just slapping in a outboard motor stator and coil
components  is no guarantee it will work as the operating design
rpms are quite different and the speed range on the rotary quite
wide.  Output voltage and efficiency varies with rpm so voltages
will be all place.  You may need a DC- DC converter circuit board
to smooth out the voltage.

Doug in Japan

Good idea Doug. Circular or cylindrical magnets are much easier
to buy that is for sure and much easier to implement. Maybe no
cheaper. We are looking at $100 for just four. The cheapest is to
find an old outboard motor and scavenge the magnets out of the
flywheel.
  I'll do a dwg using the round magnets.
  Voltage variation on the CD ignition system will not be much of a
problem. Outboard motors have to have spark at starting
RPM's too.
  You may not get 12 volts at start up but 6000 RPM at cruise
will be no problem.
  -------------------------------------------------
  To make a magnet carrier out of this will require a new plate
and cutting down the Ford spline flange. The number of
rivets Tracy used is way over kill. My RX8 clutch disk
has only four. The rivet circle diameter will have to be reduced
to make room for the magnets. Round or other wise.
  Paul Lamar
  --
Paul,
I appreciate the circuit diagram.  Thanks for posting it. Instead
of another triggering coil weren't you considering using a hall
sensor circuit?
I personally wouldn't mess with trying to make an alternator and
just concentrate on two [ignition-charging] coils.  Alternators
are cheap and well tested with high regulated amps in a small
package.

Doug in Japan
I tend to agree with you Doug on that. In fact one might
spend less money just using an alternator.
I just weighed Tracy's damper plate and was shocked to find it
weighs 5 pounds. Here are some places to machine to save a pound.
I also placed 4 round 1.5 inch  magnets but I don't think it is
practical to install the charging coils here without a major
redesign of Tracy damper plate. Just not enough space
between the damper plate and the PSRU adapter plate for both
agnet and charging coil. Perhaps with large 2 inch dia. holes in
Tracy's PSRU adapter plate that the coils could poke through.
Paul Lamar

Paul,
While I like the magnet research, why not use the flywheel from
the outboard?  If you use the stator and flywheel you get the
entire system.  I mentioned this a couple of years ago when
researching the Mercury system with Orbital direct injection
my 20B.  The orbital system requires an air pump to assist the
injection, but as a bonus you get an oil injection pump that you
an use to feed 2-cycle oil to the apex seals.
I turned back
because I was laid off and couldn't afford to buy the stuff at
the time but it appears very workable.  Even the typical RPM
atched up well as 6200 is normally max but the racers turn much
higher than that.  The 6 cylinder or 3 cylinder 2 cycles would
work for me.  The 4 cylinder for the 2 rotor.  You might need to
machine the flywheel for a new center to work on the rotary but
that wouldn't be real hard, simple turning.
Bill Jepson

Too heavy at 6 pounds for what it does. We also do not
need more rotational inertia on the front end of the e-shaft.
Paul Lamar


Paul,

Ok Paul 6 pounds, but don't forget that that includes an
integral alternator. BTW my e-mail is messing up the posts
sorry for any foul up. The motorcycle stator systems from old
2 cycles would also work. The outboard systems are designed for
continuous high RPM though, and are generally tougher.
Bill Jepson

What email program are you using Bill? Any idea why it is
doing that. Rather strange. I have to go through everything
and re edit. It looks like it is cutting off the first
character in every line that has no space character in
front of it. Do you have it set to plain text?
Some times html screws things up big time and it is
not needed. A word is a word regardless of the color
or font.

Paul Lamar

Paul,

I understand about the weight of the flywheel housing on the end
of the e-shaft where the PSRU is located so what about putting it
on the other end (i.e. where the pully's are)?  I know space may
be an issue on some designs, but there has got to be a way to do
this.
I'm also going to try and make a test rig using a high speed
electric motor.  Unfortunately the sensor coil / spark advance
mechanism on my Johnson outboard is totally shot, so I will have
to try and pick one up for testing purposes.

Franklin

The pulley end is the right place for it IMHO.

If I chuck the front hub with
the bolted on pulley in the lathe I can take an small internal
cut out out of the steel pulley to insure it is concentric.
Then press in something that looks like this.
The groove will be filled with uni carbon to cut
the rotational inertia and increase the burst strength.
Important at 7500 RPM.

-----------------------------------------------
Don't bother to get another sensor coil / spark advance
mechanism as it will not work with the rotary. I think
the timing is wrong as it will fire the plugs every
90 degrees and that is not what you want. I will show
you how to build something  that will fire two plugs
at 22 degrees BTDC and then 2 more plugs 180 degrees
later. That is what you need for a two rotor.

All you need is the charging coil assembly that
looks like this. 4 cyl stator OMC.

It would be good to cut down the flywheel on a large
lathe as much as possible to reduce the weight or better yet get
the magnets out of it without damage.

BTW Franklin where are you geographically speaking?

Paul Lamar



Paul, casting was in Ups tonight. I have a 16" engine lathe if you want me to thin up that flywheel.

milo

That is great news as we have all sorts of work that needs
a large lathe. Franklin do you want to farm out cutting
down that flywheel to Milo?

Do you have an engine running on a test stand Milo?

Paul Lamar