http://www.torque-online.co.uk/news/?p=3631
      --

      Paul Lamar

   Paul,

   Did this kart have ceramic bearings and if not when (if ever) will
   the AIXRO folks add them?

   I have not seen any reference to it, but do they have the liquid cooled
   shaft per the paper you have linked to i.e., the "LCCR" ?

   Also,
   I see the Cubewano UAV Wankel is using Ceramic Coatings on the
 Rotor  and the epitrochoid surface, as well as claims of lower BSFC.

   Any comments?

   My best,
   Anthony

   Those questions are above my pay grade :) Send your questions
   directly to:

   Poul Henrik Woelfle AIXRO <ph.woelfle@woelfle-engineering.com

   I will say IMHO ceramic coatings on the rotor are not worth the
 risk  of damaging your rotor housings when it comes off.

   BTW they have a new very nice web site.

   http://www.woelfle-engineering.com/index.html

   Paul Lamar
   --

   Hi there,

   First, thanks to Paul for publishing the links.

   Now to the questions:
   The engine may have had ceramic apex seals, but there is not so
 much  of a difference to standard seals. The biggest difference is above
   8000rpm, where the ceramic seals produce less friction and allow
 for  some more top-end power. Even if it's about 3hp (that's 6% on a
  45hp engine), the average karter will not really notice the
  difference though. On a side note: We hardly ever see any wear, but
  we do see some "running in" with the standard seals. Therefore
 changing from standard to ceramic on a used engine is no good unless
  the trochoid housing is exchanged as well.

   We have tried ceramic rotor needle bearings, which were good for
   lower bearing temperatures. These things are very sensitive though.
   If anything manages to get into the bearing (dirt, etc.), the
   needles will dissolve and destroy the e-shaft, rotor, seals and
   housing, i.e. the complete core engine. The apex seals are much
 less  sensitive to such occasions, because they can wipe potential
 dirt or  the like out the p-port exhaust. For this reason we don't
 use  ceramic bearings. Ceramic coating of the rotor and housing is surely
   interesting, and when it works it's great. But I agree with Paul
   that getting it right is a difficult exercise, especially in aircraft.

   Our trochoid housing and side plates are from aluminium and water
cooled.
   The E-shaft is charge cooled. Of course a liquid cooled shaft (or a
   completely different rotor cooling/lubrication system) would allow
   for more power, but it would also add to the cost, weight and
   complexity of the system. The charge cooling system we are using
   works fine in the intended power range.

   Best Regards,
   Poul

   Let me put on my devil's advocate hat here for a few minutes with
   some assumptions and questions. The devil is always in the
   details... especially with a rotary engine.

   Since the kart engine is limited to 10 seconds at full power for
 max  HP, what percentage of max HP can it run at full power for 5
minutes?

   A certified aircraft engine must run at full power for 5 minutes at
   a time according to the FAA.

   I assume this is due to the rotor bearing temperature in the charge
   cooled rotary engine.

   Lets also assume for the moment that the dirt particle capable of
   shattering a ceramic needle bearing is made from diamond, being the
   hardest particle I can think of right at the moment.

   What diameter of diamond particle relative to the diameter of a
   ceramic needle causes the needle to shatter?

   Can we come up with a filter that will remove particles that size
   and above in the premixed oil/fuel mixture before it is added to
 the  fuel tank?

   Can we come up with a filter that will remove particles that size
   and above in a filter on the engine located in the fuel/oil feed
system?

   What is the best place to put a thermal couple to measure the
temperature
   of the rotor bearing if that is in fact possible?

   Paul Lamar

   Paul,

   My experience with WOT running problem was self ignition, once on
 an  air cooled engine motorcycle I switched the ignition off and
 rode a  full lap to make the point to our Chief Engineer, I tossed
 the keys  to him as I passed, we switched to water cooled shortly
 after. Even  on water cooled we had the problem but this was plug
 orientated, a  nodule would build up on the plug and this acted like
 a glow plug, scraping  the nodule off gave a further say 100 odd
 mile of High speed WOT running.

   On Rotor bearings we had special ones with low skew grade, and in
   fact we used to use a skew test rig, this consisted of a ground
   shaft spinning at a set RPM with a loaded bearing the axial thrust
   being measured. On WOT work we had the Eccentric shaft grow by

   0.0001" per 1000 miles, and the new build clearance did not help
 the  noise emitted by a air cooled engine, we Cryogenically treated the
   Shafts to stabilize and speed up the Growth prior to final grinding
   and in so doing we was able to reduce the new build clearances and
 noise.

   Bob
   UK

   A few years ago it was determined most engine wear was caused by
 particles of 5 to 25 microns size. At the time and I suspect even
 today, that most filters only removed particles larger than 40 microns.
   With charge cooling, dirt in the intake air will be the culprit.
 The fuel/oil should be fairly clean and not be the start of a
 problem unless care has not been taken transffering the liquids.

 Dale Davies

 Poul, Suppose for the moment you built a two rotor with a full
 pressure fed oil system and a planet gear box. What would you have
 to charge for it at a quantity of one per week for the non certified
 Light Sport Aircraft market and the US experimental market.

 We need a light weight 2 rotor 100 HP engine for aircraft service.

 Take a guess.

 Paul Lamar

Poul,

 Out of curiosity, are the rotor housings and end plates hyper-eutectic
aluminum, with the aluminum lapped out to let the seals ride on the
silicone
or do they use a steel liner? I realize intellectual property is involved
and
the lightness for a kart engine is a factor in the design. Thank you for
what
answer you can provide.

Dale Davies


Paul and Poul...

Thank you for replies and further education us on rotary design and
potential directions going forward.

I have mentioned this before but I am curious ( this question is for you
Poul )  have consider the following coating(s) ? :

http://www.microblueracing.com/

While to some it may look like a fad etc. their racing victories continue to
add up.
On top of that is the interest with "Large Rigs" looking for reductions in
friction to increase fuel economy.
However, their video of a leaf blower (2 stroke) fully treated with their
coatings running @ a 200:1 fuel/oil ratio got me thinking a while back....

So my question in that regards is, if this works on a 2 stroke, with all
their lubrication and cooling challenges, would this patented process in
conjunction with their Ceramic Bearings be a game changer for Charge Cooled
Rotaries such as the AIXRO?

I say this in all seriousness, as just an amateur observer of engine
technologies ( and sometime magazine contributor) my gut feel tells me it a
natural fit.

With that in mind, does anyone here on the Rotary list have an old Sach's
Snowmobile Rotary that runs that I purchase  ( at a resonable price ) to
send to Microblue to actually see if these bearings and coatings work?

My best and I look foward to your replies.
Anthony J. Liberatore

What is it and how is it applied? Until they tell you that it is just another
scam.


Paul Lamar