Nf-ID: #R:andrew.cmu.edu:6:trsvax:1195667324:000:4228
Nf-From: trsvax.tandy.com!earl    Nov  9 10:19:00 1992



/* ---------- "Non total-loss oiling?" ---------- */
Hey folks, 
I am wondering about lubrication systems as applied to
model aircraft engines.  I have several helicopter engines in various
sizes and they are all two strokes, and all use total loss oiling.
I am also under the impression that model four strokes (and the O.S.
wankel?) also use total loss oiling.  How does the lubrication system
work on a four stroke?
I am aware that there are full-size two and four strokes that get by
without total-loss oiling and are much more "green".  Of course, many 
full sized two strokes (like in my motorcycle and lawn-mower) still
burn their oil as designed.
What I am getting at is, are their any model engines out there that
don't burn their oil?  Either wet or dry sump designs would be 
acceptable.  I am just looking for something that is a little more
environmentally conscious.  Actually, I am looking for something that
can run on pure alcohol or propane and thus be run indoors.
What about that O.S. wankel?  Any experience with it?  What about
the O.S. supercharged four stroke engine?  Is that still total-loss?
Does it use regular tappet valves like an automotive four-stroke?  How
is it lubricated?  Could it be modified?  Have any folks out there
ever tried to modify an engine to be lubricated in any way other then
total-loss oiling?
Thanks for any and all opinions.
Good flying!
CB
***************************************************


   There have been, off and on, some limited production to prototype examples
   of sump lubricated engines. Most of these are rare collectors items.

   The only production sump lubricated engine, at present, is the KAVAN 50cc
   four cycle model engine. It is a OHV pushrod operated engine, with neat
   Continental Logo'd valve covers. Naturally, you can't fly it inverted for
   too long. It also requires a little bit of oil in the fuel for lubricating
   the top end, about 5%.

   All of the OS four strokes depend on blow by past the rings to get the 
   bottom end lubricated. As a matter of fact all of the other four stroke
   engines use the same principal too. Some notable exceptions are the
   YS 120 chamber engine and some of the multicylinder engines; these engines
   run the intake fule charge through the bottom end, before it is run into
   the combustion chamber. The OS supercharged engine, is a OS 120 with geared
   fuel pump and a roots blower mounted on the rear; it still uses piston blow
   by to lubricate the lower end.

   Model radial engines all run their intake fule charge through the crankcase
   before it is sucked into the combustion chambers. There are some custom
   built model engines that don't do this, of course.

   Hobby Lobby once (circa 1977,78) sold a 4 cylinder inline OHV engine with
   sump lubrication, but by the time I had enough money to get one, they had
   discontinued it. I wanted to do a Pietenpol or Heath Parasol plane with it.

   The OS Wankel, basically uses oil in the fule to lubricate it to. It uses
   oil to lubricate everything and to help seal up all of the tiny precision
   tolerances.

   A company in Sweden once manufactured some very nice twins as OHV engines.
   They stated that their engines needed no oil at all in the fuel to run.
   Unfortunately they went out of business, as their engines were very
   unreliable and broke rods and crankshafts quite regularly. As far as I
   can tell all of the examples left, have been run once or twice and broke
   down, or have been never run at all.

   If you really want to be enviromentally safe, you need to seriously
   consider electrics. Astro-Flight recently came out with a Astro 90 motor
   that makes me drool with want.

***********************************************************************


<This information is provided by an individual and is not nor should be
 construed  as  being  provided  by  Radio  Shack or Tandy Corp.  Radio
 Shack/Tandy Corp has no obligation to support the information provided
 in  any way. > 
						
						Earl W. Bollinger
						@ <earl@trsvax>


"You were in the Clone Wars!", said Luke excitedly.
"Yes", replied Obi Wan, "I was a DOS programmer. But that was before the dark
 times, before OS2."



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