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Category: Archive 2009
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Table of Contents SEN 1297

 

  1.  August Circles
  2. More Hot Rotation
  3. FFQ

 

 

 August Circles

 

Hot Circling:
As a full scale sailplane pilot I have shared many thermals with birds of  several varieties circling in both directions.
BA

 

 More Hot Circles 

Thermal rotation 

 

The responses to the question of thermal rotation direction have been most interesting.  But it seems the phenomena we free flighters call thermals are, for the most part, more properly called plumes.  In addition, the variables contributing to these phenomena are quite complex.  Simple first-order analyses of observations are probably not valid.   Please see the discussion found at www.rc-scan.com/tech/thermals.htm  for an introduction to quite a bit of research on the subject.
Chuck Markos

 

 New FFQ

  This new issue of Free Flight Quarterly presents three articles on the very interesting research being done to increase the additional height of the bunt maneouvre at the end of the tow in the case of F1A gliders. Two schools of thought here, one which uses a large flap deflected up to decrease airfoil drag during the bunt, and then lowered for normal glide, the other that seeks to achieve the same drag decrease by careful reshaping of the airfoil without the need for the mechanical systems of flap actuation. Each of these contrasting ideas has proved viable and one of the articles tells the story of some recent trials at Taft to test the second, the special airfoil concept.
    Ken Bauer talks about RDT (radio controlled DT), the history and development of this great idea, with considerable detail on the units he has been producing and including tips on its most effective use.
    There are of course a number of other articles in this issue of  the magazine, and scale modelling is well served with the second part of the Buecker Jungmeister peanut article by Thierry Bachellier, an outstanding biplane model that has performed very well . Bill Henn contributes his thoughts on how to win at Geneseo, the choice of models, propellers and motors that can lead to victory in this highly competitive category.
    Jean Wantzenriether continues in his exploration of the role of the stab in the performance and stability of rubber models, considering now how to optimize its role in the climb and glide without the need for VIT. This is the second article of a four-part series.
    Tailless models appear again with the Longbow and Black Vulture designs of John Kay in both glider and powered versions, models that have been highly successful in tailless contests recently.
    The much loved Mills 1.3 cc sport Diesel engine is studied by Ron Chernich, covering its design  and evolution, as well as the many versions that have come up after the production of the original engines ceased more than 50 years ago.
    An outstanding Open Rubber model has been very successful in Australia recently. This design by Don Boughton of Victoria combines a sophisticated structure with a three minute prop run to achieve a colossal performance. This model has been refined for practical performance in  rough fields and the article presents plan and background notes.
    Further details on this new issue can be found in our website : www.freeflightquarterly.com

Sergio Montes

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Roger Morrell

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