Paul, and Poul,

Their Patent Application Technology PDF attached. They are using  tungsten
disulfide and  a polishing process.

They are not the only Utilizing this using this coating developed by
Stanford for NASA.

Google : tungsten disulfide

http://www.dynacron.com/aerospace.html

http://www.ws2oil.com/index.html

http://www.carterbearings.co.uk/material_td_coating.htm

http://www.tecvac.co.uk/coatings11.php

On fishing reels....

http://jackerskine.com/tungsten_tuff.html

Other info...

http://www.dicronite.de/Dicronite08.pdf

http://4lube.co.nz/Downloads/MK-WS2-06-01WS2VMoS2.pdf

I look forward to your feedback.

My best,
Anthony


  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 reductionsin
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

Dear Anthony,

Thank you for your messages and your valuable input. There are lots or
different treatments to reduce friction on the market. We have tried some
different coatings over the years, but until now we have not really found
something that was worth the extra effort.

Still we just spoke about something similar to what you describe with our
American distributor a couple of weeks ago. His daily business is engine
tuning, so he is not only looking for improvements for our engines, but also
for his customers' engines. They care more about HP than about money, so
it's a good playground.
He was going to have the main bearing's running surfaces treated. We already
use a very hard and flat bushing as a running surface for the main bearing
in the rotor, but it could still be beneficial.

As for using ceramic needles we are now very cautious as I have tried to
describe on the newsletter as well. Maybe we'll give it another go for a
flying engine at some point. The inlet air is a lot cleaner for aircraft,so
the probability of dust getting into the engine is quite a bit lower. We'll
see..

I will keep you updated with specs and test results on this surface
treatment as you will surely be interested to hear the outcome. I assume it
will take a month or two though, depending on when they get to test it.

Thanks again and best regards,

Poul Henrik Woelfle

Woelfle Engineering GmbH
Randstraße 109
D - 47804 Krefeld
Tel. +49 2151 151020
Fax +49 2151 151019
www.woelfle-engineering.com

HRB 7369, Amtsgericht Krefeld
Geschäftsführer: Paul A. Woelfle