National Free Flight Society

SEN 2160

Table of Contents SEN 2160

  1. USA Nats Info
  2. For sale
  3. Looking for Polyester Cloth
  4. FFQ
  5. Junior World Champs Blog Link

Where to find USA Nats Results
The results are here: note it sometimes take a little while for the results to appear and stories and photos at

For Sale – F1B / F1G:

  1. F1B model – 1900 mm wing span BE6949FVNC2 profile , Tony Mathews design , the model has fixed pitch front end and there is option to fly it with VP front end from Igor Vivchar , electronic pylon with Sidus timer with option to put Blinker . all the fuselage and tail boom was build by Stepan Stefanchuk , the wing was build by Mihaly Vardi, the model is trimmed .
  1. F1B models – Two models Stepan 1800 mm wing span with Favionics timer FX11 and VP front end (A.A front end)  , Stepan build both of them and they are in new condition and trimmed.
  1. F1B model- 1520 mm wing span with mechanic timer and two set of prop blades.
  1. Two wings 1710 mm wing span both of them made by Stepan Stefanchuk ( one of them i covered (half wing red and one tip yellow) both of them are new
  1. 1640 mm wing covered with polyester paper
  1. Evegny Gorban VP front end , fix to Stepan nose ring
  1. F1G model – F1G from Alexey borduv , new condition (never flown) mechanic timer , with V.I.T and all the function that you need for F1G
  1. F1B complete mechanic pylon , made by Stepan , very good condition
  1. Igor Vivchar F1B prop blades with easy clamp for A.A front end (new)
  1. Alex Andruikov F1B prop blades with easy clamp (new)
  1. F1B prop blades made by Russian builder  (with hole for 4 m”m pin) (new)
  1. F1B prop blades made by Evegny Gorban (new)
  1. F1B Stabilizer D-box 2.60 sq/dm covered (new)

For more information or question: Facebook: Or Shabat  E-mail:


Looking for bulk Polyester Tissue/ Polyspan
From:Terry Bond

The New South Wales Free Flight Society needs some polyester tissue for sale to its members.
Could you post this in SEN and ask where can we get this in bulk; ie by the roll.

Regards  007

Summary of articles in Free Flight Quarterly 360 for July 2016

The editorial traces the success of a relatively new Czech FF magazine: Volny Let. Volny Let draws on the strength of the Czech Republic active and vigorous FF movement.

*Andrew Longhurst*  goes back to his early youth, when in the early 1950’s he built  the Milli, a small power model of 38″ span, designed by  HP Aaser, from Norway. The original plan and article appeared in Model Aircraft in March 1951. After more than 50 years, Andrew built another copy, powered it first with a Mills .045 and then with a DC Merlin, which was not only lighter but also much more powerful.  A nice-looking , easy to build model , endowed with a phenomenal glide and, with the Merlin, it gets into a fast vertical climb. Andrew seems a bit awed by this performance and  recommends to “forget your Tomboys”. Comprehensive construction notes are included in the article.

The late *Ron Chernich* wrote most interesting and persuasive article on engine-related topics. Here he traces the invention of the glow-plug for small model engines by Ray Arden. Although the idea was not strictly new, as glow-plugs had been used in large truck Diesel engines, Arden’s inventive genius developed a small, compact and cheap glowplug, together with the fuels needed for easy operation and this invention revolutionized the engine world in  the late 1940’s. His jewels of  engine design , the Arden 0.099 and 0.199  are also described and  contemporary engine tests are  quoted to establish their performance. Arden was a truly astonishing personality, with more than 400 successful mechanical patents to his name in a wide diversity of  themes.

*Michel Coviaux* pokes fun  at the ecologist world  with this cartoon, where an F1G flier is praised for his ecological conscience. This praise astonishes him, as he has found that not all is well in the contest world, even with balsa conservation.

*Massimo Ursicino* is one of the several electronic timer manufacturers, and has developed in Italy a wide range of electronic and mechanical products that are used in  FF models, in particular but not exclusively in F1C. In this article he gives a short description of the products he makes. Prominent among then are his versions of the radio controlled DT system, an extremely useful device at this time , when only smaller and smaller fields are available for contest meetings in most countries.

It seems that successful FF contests are victims of their own success. The fly-offs, that gather a large percentage of the competitors are difficult to manage, as, when the body of fliers that have qualified for the fly-off see one of them  engaging good air, there is a sudden, frenzied movement towards a mass launch after the first, audacious contestant. The author the article, *Aram Schlosberg*, suggests that this “massive piggybacking” should be curtailed by appropriate rules related to the number of flyers that can fly simultaneously from a given pole. His strategy is not simple, but could be useful in  solving this complex contest organization problem.

MID103 is without doubt one of the most popular of the LDA airfoils for F1A and F1H models, since its debut some six years ago. Essentially it is a 7% thick airfoil with a 4% camber to ensure very low drag during the vertical zoom launch. Its creator, *Slobodan Midic*, proposes now a variant, the MID103 c55. This variant is quite similar in most respects to the original MID103 ( same maximum and thickness distribution) but the maximum camber is increased to 5.5 %. The advantages of this modification is a  much enhanced glide performance. There is of course a price to pay… as detailed in the article.

Lubomir Koutny*, that master Czech scale builder and designer has produced one of his most complex creations, a scale model of the Bernard HV220 Schneider Cup racer of the mid 1930’s. As well known, these racers were low-wing hydroplanes powered by very powerful motors, and achieved incredible performances, some of their speed records still stand 82 years later. A latecomer to the Schneider Cup races was the extremely beautiful Bernard HV220, on which the French state lavished a great sum of money in search of international prestige, as did other countries. Because  Bernard aircraft are not particularly well-known, *Sergio Montes* has written an introduction on the background of this interesting racer, followed by the scale article by Koutny, in which details of the rather complex construction and covering are described.

Michel Coviaux* had published previous articles about his novel mid-propeller F1G models, models that he labels ” Pousseurs”, for their pusher propellers. They use Depron wings, some of them employ Jedelsky- type airfoils. Michel relates here the long development of these models, where variations of the wing dihedral, airfoil, propeller type, diameter and number of blades have gradually improved performance and reliability. THis is an interesting exploration of different propeller layouts, and especially of the use of very large propeller diameters.

A perennial question for designers and builders is the proper location of the CG of the model. There are a number of empirical equations for the determination of the location of the CG, equations that produce acceptable results, but little insight on the  stability of the model using that particular location of the CG. *Sergio Montes* suggest that a more correct determination of the position of the CG can be derived from the calculation of the location of the Neutral Point of the model. Once this stage has been solved, the designer can specify the degree of stability that a given model needs and thus  define the location of the CG. The article reviews several methods that determine the place of the Neutral Point in a model, methods that are derived from a theoretical analysis of the forces and moments acting on the model. Once the geometry of the model is known, wing and stab areas,  and tail moment arm, the theoretical methods for the Neutral Point determination are reduced to a simple graph. A modern F1A is used as a test example, both for the theoretical methods and for the most comprehensive of the empirical methods, that of René Jossien.

Chris Stoddart* has written several articles on the calculation of the performance of propellers driven by electrical motors. In this 4th installment of the “Properly Speaking” series he implements Helmut Schenk’s procedure, freely available in the Internet. This method is used to analyze the performance of a system installed on an E36 model. The propeller characteristics are taken from the tests at the University of Illinois at Urbana Champaign. The Schenk procedure provides an extremely comprehensive  analysis of the performance of the motor.

Two designs for beginner’s F1B models are presented in the last article: /Tilka/ by *Bror Eimar* and /Welles/ by *Klaus Salzer*. Both models are well known, simple to make and of sufficient performance to have done well in contests against more sophisticated designs. We present here what I believe is a later development of the Tilka, also by Eimar , with several more advanced features in comparison with the original 1970’s design.

The cover  (with Stepan Stefanchuk) and the index of this new issue can be seen in our website :

Sergio Montes 

Junior WC F1ABP
From:Bernhard Schwendemann

on 1. August the Junior World-Championship will start in Prilep (Macedonia, former republic of Yugoslavia). On the web-page of the German free flight magazine the blog has already started:

We will report regularly with text and pictures about this event.

Best regards


Roger Morrell