<< Jerry Hey wrote:
 >
 > Predictable performance is a critical part of making up a firewall
 > forward package for any design.    For the Tailwind,  I originally  set
 > the goal of 180 hp/6000 rpm with a NA 13-B.  I was told that should be
 > no problem.   But exactly how does one achieve that performance?
 > Assuming Tracy's ignition and fuel injection,  we still have the exhaust
 > system  and intake manifold design.   Also, there is the issue of
 > Street  Porting or even a mild PP if there is such a thing.  Can anyone
 > say that if I do the following, the HP will be............?   If the NA
 > rotary can deliver180 hp, then it may very well become the engine of
 > choice for the Tailwind.
 >
 > Of course,   the recommendations have implementable.  No point in
 > talking about a tuned exhaust, if there is no place to put it.
 >
 >   I want to go on record to the Tailwind community saying what is
 > possible.  I would like to provide a list of SPECIFIC  RECOMMENDATIONS
 > on  how to set up the engine to achieve the performance.
 >
 >     Although, I have followed the debate about spinning engine faster
 > (and faster) to gain more hp that is not what I am talking about.   What
 > HP can be made at 6000 rpm?    I like this engine speed for the TW
 > because of the reduction ratios of Tracy's drive and  because bearing
 > loads are lightest at this rpm.  The Tailwind does not need more than
 > 180hp under any circumstances.   It is a very  hot performer with an
 > 0-320.
 >
 > Jerry

 Tracy has about 180 HP with long intake runners and no inserts in the
 exhaust ports. His exhaust system is nothing special with a Y in the pipe
 too close to the rotor housings. Everett said the optimum individual exhaust
pipe length
 is about 32 inches. Also Tracy uses the high compression rotor in a four
 port turbo engine. As I recall Bruce did some mild street porting on
 the side ports. Nothing earth shaking here. No one thing made much of a
 difference. To get more or to be sure you are getting at least 180 and
 probably over 200 at 6000 RPM go to peripheral ports like Power Sport.

 Paul Lamar >>

My .02: "Predictable performance" should be backed-up by "verifiable data"
for the engine configuration that you define. What I mean is that you should
fully define an engine hardware configuration (porting, compression ratio,
intake manifold design, exhaust length, etc.) and then run a properly
controlled dynamometer test to create a complete data set -- torque curve and
fuel consumption map, perhaps some indication of the effect of F/A ratio on
fuel consumption at part throttle settings. It's probably too much cost to
also do altitude simulation, but the piston engine corrections are probably
pretty good for rotaries as well. As you suggest, there is a lot of
speculation on the power output of various and sundry engine configurations,
without a whole lot of objective data.

Jon Lauter
Rotary Power Marine Corporation

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org