Issue 63 – Published and distributed in JULY of 2017. Click on image below to read the table of contents.
The Editorial of this issue joins the obits of two important modellers, Gérard Pierre-Bès in France and John O’Donnell in the UK. The first one was written by Jean-Pierre DiRienzo and the second by Dave Hipperson. To the shorter obit by Di Rienzo we have added some interesting material concerning the designs of Pierre-Bès for universal joints for detachable nose-blocks in rubber models.
We finish the selection of model aerodynamics material from Frank Zaic books with his now classic study of the climb of the Taltos II power model. Ernö Frygies, the designer of this model won the 1964 W/C with this very advanced model (for the time) one of the first to use VIT. Zaic showed how could one predict the flight pattern and (most importantly) the attitude of the model during the climb. It is really a superb explanation of many complex aspects of model aerodynamics, and all with the simplest mathematics.
George Perryman, well known to readers of Free Flight Quarterly, speaks about his Lanzo Stick models. George was fascinated by the simplicity and performance of these large rubber models, that he used in preference to his own designs for the initial rounds of Mulvihill and Open Rubber competitions for many years. There is some analysis of the design features of the Lanzo rubber models.
One of the tools that we use frequently to trim a stalling Free Flight model is to induce a tighter glide circle. Frank Zaic was perhaps the first to explain in simple terms why circling flight achieves this purpose, with material that he wrote for the 1952 Yearbook, and expanded 12 years later in a full book with the name ” Circular Airflow”. The present short note by Sergio Montes fills in the details that Frank omitted in both publications, arriving at the correct formula that Zaic quoted in the 1964.
Frank Perkins has developed a couple of extremely light-weight DT actuators using “muscle wire”, a material that changes length when acted by an electrical current. The simplicity of these actuators, together with the light weight of miniature batteries available today, enables the use of these systems even in the lightest models. Perkins illustrates the application to a couple of small HLG designs, but the use of such actuators is much wider, and can be used in a comprehensive range of free flight models.
Hank Cole is very well-known name to most free flight enthusiasts. His long (seven decades) and successful career as modeller and aeronautical engineer and scientist in USA is simply without par in the history of Free Flight. The present biography tries to present balanced account of both aspects of Hank’s aeronautical and model aeronautical interests, with illustrations of some of his many successful models. A list of his model publications and scientific papers, which he, at the age of 96, continues to produce is appended to the article by Sergio Montes.
Tapio Linkosalo has developed a most interesting E36 model. It started as a reduction of a famous Finnish 1960’s FAI model by Sandy Pimenoff, but , when the performance of this model fell short of what was wanted, Tapio opted to follow some aspects of the competitive Pearl E36 design, mainly wing and stab planform and moment arms, but using his own structure and airfoils. In the search of a stable spiral climb he felt compelled to adopt a pylon for his model, as a wing over fuselage version proved unstable in the climb. The addition of a pylon worked superbly and the resulting controlled climb to more than 170 m fulfilled the designer’s expectations admirably.
The history of the development of the Yin Yan (Silver Swallow) Chinese Diesel engine of 1.47 and 2.47 cc enters a second part. Adrian Duncan gives a careful appraisal of the various production versions of this engine, which was produced in very large numbers and exported with some success to USA and Europe. The good design features were let down in the later versions by rather indifferent construction and preparation standards.
The low-drag airfoil MID 103 has been one of the most successful airfoils of this type and the designer, Slobodan Midic, has produced several variants of this type. The ones contained in this short article concern two versions of 4.5 an 3.0 % camber, suitable for the inner and tip panels of an F1A wing, respectively. XFOIL diagrams with calculated aerodynamic coefficients CL, CD and CM and airfoil coordinates for both types are included in the article.
As an illustration of the models designed by Hank Cole, we present here a rather rare design, his Cirrus Cruiser, an AMA Class C design of very pleasant lines. It was flown first in the 1946 USA Nationals. It has a tapered wing with undercambered airfoil and the wing is set at a very large 8 degrees incidence, the stab at 5. The argument is that when gliding at the most efficient CL and CD, the fuselage remains horizontal, thus minimizing the drag. Could be an interesting rival for the Gollywock or Casano Stick in that small rubber class.
Dave Mitchell produced in 2014 a superb rubber scale model of the Waco Standard cabin model QDC with 24″ span . The model is based on an actual aircraft, found in derelict state some 20 years ago and painstakingly restored by a California aviation enthusiast. A short history of the Waco Standard Cabin models is included, which clarifies to a certain extent the bewildering array of sub-models in these series that started in 1931. Mitchell describes some aspects of the construction and flying of his scale model, which has garnered first prizes in FAC contests. Stable, high climb and a “matronly” glide of this scale biplane with an ample fuselage are significant achievements, as is the robust, yet light structure that has allowed a long contest life. There are many outstanding photos of the model in action due to Captain Pat Daily.