While various events conspired to keep the attendance at the fly-in/seminar at Slobovia Outernational Airport in Pocahontis, MS less that it could have been, Those that attended were rewarded for their efforts. 

 

Charlie and Tupper England deserve special recognition for hosting the event with such enthusiasm, thorough planning, and "Southern Hospitality".

 

The three rotary powered aircraft that flew in were diverse examples of the adaptation of the rotary engine to aviation use:

 

Tracy's modified RV8 uses a normally aspirated 3 rotor 20B which he reports to have outstanding power reserve for take off and climb while operating at economy cruise at manifold pressures lower than normally associated with flight requirements.  This brings to mind the proverb that "there is no replacement for displacement".

 

Bobby's Renesis equipped RV10 demonstrates the enhancement of displacement by the use of a supercharger to extract sufficient reliable power for the larger aircraft.  This approach effectively increases displacement by boosting the manifold pressure.

 

Dennis's Renesis powered RV (7A?) uses dynamic tuning of the intake manifold to optimize volumetric efficiency of the engine at RPM ranges appropriate for flight.  This approach effectively enhances the displacement of the engine under selected conditions through design choices made in the construction of the intake manifold.

 

Examination of the three aircraft engine installations with the cowls opened evoked discussions of cooling challenges.  The importance of cooling inlet location, shape, and size was discussed.  The sometimes (often?) non-intuitive effects of diffuser shape and heat exchanger geometry were also demonstrated in these installations accompanied by many questions and answers.  The importance of cooling air exit strategies did not escape without examination and analysis.

 

A presentation on possible explanations for the SAG phenomenon was given.  The discussion that followed, particularly the observation by Tracy of an instance where the appearance of SAG was reversed by a change from 100LL to mogas, made it clear that investigations providing possible answers inevitably create more questions.

 

Bobby gave a presentation on the challenges of implementing the supercharger in his Renesis installation with regard to decisions affecting efficiency and reliability.  Extracting heat from the installation with respect to coolant, oil, and intake charge temperatures was shown to be critical.  The necessity for the compromises to be made while maintaining the underlying goal of safety was emphasized.

 

Bill gave a presentation on his research into the aspects of cooling related to water pump performance.  The methods used to produce the data and the implications of that data with respect to belt driven stock water pump installations as well as electric water pump installations was discussed.

 

Phil brought his partially completed intake manifold for his 20B to show.  This was the basis for suggestions on intake design and construction based on experiences and observations from both the aviation and automotive arenas.

 

The subject of exhaust header and muffler design with respect to power, construction, noise, and reliability inevitably found its way into the discussions.  The difference in requirements for the peripheral exhaust port of the older 13B engines compared to the requirements for the side exhaust port of the Renesis engines was agreed to be of major significance.

 

There was a discussion of alternatives for tuning the controller mixture correction table arising from the effect of injector dead time.  Tracy, always two steps ahead, indicated that a controller dead time correction has been implemented in recent controller programming which should simplify the tuning process.  With regard to the two steps ahead, Tracy also reported on the positive results of the auto-tuning function and the implementation of a closed loop mode of operation (that's at least three steps ahead, isn't it?).

 

Dennis mentioned that he has what seems to be an intermittent single misfire in stable cruise occurring several minutes apart.  Tracy responded that he had recently discovered and corrected a programming structure where an unlikely simultaneous occurence of events could cause dropping of one ignition cycle.  So it is possible that a controller update may resolve this intermittent miss.

 

Dale and Charlie are at the point in their projects where they are faced with decisions on construction of their intake systems.  Dennis indicated that he has ideas in this regard based on his experience.  It is possible that some answers to their questions may be obtained from the engine test stand in Wyoming.  Of course they were reminded that the answers will come at the expense of additional questions.

 

Dennis has initiated an inquiry into the possibility of making the B controller more redundant by implementing an independent crank angle sensor for it.  We are always reminded of the safety implications of our decisions as they may impact those who trust our judgment.  Beth, Carmen, Dianne, and Shirley genuinely enjoyed the activities arranged by Tupper as well as just "hanging out".  There was also at least one instance of the issuance of a reward for participation in that group.

 

Of course there were discussions of many subjects other than rotary engines at the wonderful meals both on site and at the catfish and the Mexican restaurants.

 

Definitely a weekend to remember.

 

My apologies for anyone or anything that I've left out.

 

If anyone has photos that they can send to me directly, I would be happy to try to post them on my website which may remove the image data size restriction of the list.

 

Steve