>From: <ronev...@cox.net>
:
>      What's happening on the KR net?  There haven't been any "hot topics" 
>lately.  And, no one answered my question last week.  Therefore, I will 
>repeat it:  "What would be the most favorable rotary engine to use with a 
>KR?"




Ron, send an email to either of the following web addresses.

http://www.rotaryaviation.com

http://rotaryresources.com

As one poster so round about tried to hit at, the 13B is not a satisfactory 
engine for the KR.  With the proven drive reduction unit, and all 
accessories, it come in at a little over 300 lbs.  Now, if you could do it, 
it would fit under the cowl of a KR:-)  With 180 HP coming out of a 
combustion area of 12"x12"x12"( http://rvflying.tripod.com/aero3.jpg 
).................it sure would be something to see.

However back to reality.  The first web address posted is the the lead guy 
in the rotary aviation community.  The second address if the the lead rotary 
engine guy.  I would check with both of them on this issue.  As I understand 
it, a single rotor engine is not as smooth as a dual rotor.  With a dual 
rotor, the rotors are offset to counteract the individual rotating masses of 
each rotor.

There are several interesting points to be made about the rotary.  At a 
Eccentric shaft (crank shaft)  RPM of 6000  the rotors are only turning at 
2000 RPMs.  My engine had 130K on it when it was removed running from an 
RX-7.  One exhaust port showed, what appeared to be, either a rich mixture 
or indications of one rotor housing burning some oil. When I disassembled my 
engine I took pieces and parts to a single owner machine shop just up the 
road.  As it turned out, the face of the water pump side end housing had an 
area, where the rotor reaches it's max outside point, that had a ridge 
height .0011 out of limit spec.  The rotor would not be able to get a nice 
tight fit with the side seals and thus it experienced both a rich mixture 
and some oil loss.  The flywheel side end housing's same point measured 
.0032 of step wear with the limit being .0039 and the oil seal overlap point 
measuring .0006 with a step limit of .0008.    This exhaust port was clean.  
I sent both housings to rotaryresouces for exchage.  I'll pay $75 each and 
get replacement housings that have been lapped back to 0.  Let's see you do 
that with a lycasouious.  The apex seals will be replaced but were within 
factory width tolerances of .0752 to .0763 and height of .256 to .315 The 
side seals were within factory tolerances of .1122 to .1240 in height but 
will be replaced with factory new.  The crank was also within factory specs 
along with.........believe it or not, the two rotor bearings and the two 
main bearings.

I say all this to illustrate how simple the rotary engine is and how 
efficient it is.  I had planned on replacing the four bearings but they are 
not only in the acceptable range but within factory range.  I couldn't do 
any better with new bearings.  I just looked at my truck hour meter and 
odom.  I have 40366 miles and 972 hours.  I know, I know, the engine has not 
been run continuously at 2000 RPMs but it is a little fun to extend those 
hours out to 130K.  That would represent right at 4000 hours and there was 
one measurement, on one face, that exceeded factory specs by  .0011, which 
caused a slight reduction in efficiency of one rotor.

With rotary there are three issues that must be considered.  A drive 
reduction unit is more than just an extension.  At certain RPMs under the 
normal operating range of a rotary, or any other engine, there are vibration 
issues.  These must be dampened somehow between the flywheel attach point 
and the gear system, belt system, or whatever of the reduction unit.  This 
is the most probamatic area of a rotary or subaru installation.  
Rotaryaviation has tweeked his unit to the point of reliablity.  The next is 
the intake.  It appears to an area where one can easily gain or lose HP due 
to the length/layout related to how the rotary sucks the fuel in as the 
rotor does it's thing.  Most say it can go 15% either way from norm.  The 
third is the exhaust.  As the exhaust leaves the engine it is travelling at 
supersonic speed, thus it is LOUD.  You must use a stainless steel exhaust 
system.  A little pricey.

The more I get into this engine the more I am satisfied with my decision to 
go down this path.  Like I've said before, "Sometimes when you play with 
fire you get burnt.......but most of the time you end up with a nice 
steak":-)


Dana Overall
1999 & 2000 National KR Gathering host
Richmond, KY i39
RV-7 slider, Imron black, "Black Magic"
Finish kit
13B Rotary. Hangar flying my Dynon.
http://rvflying.tripod.com/aero1.jpg
http://rvflying.tripod.com/aero3.jpg
http://rvflying.tripod.com/blackrudder.jpg
do not archive

_________________________________________________________________
Get some great ideas here for your sweetheart on Valentine's Day - and 
beyond. http://special.msn.com/network/celebrateromance.armx

Reply via email to