Many thanks to Peter Rother for the pictures and the report.

You can see more at Peter’s homepage

All the pilots and models...


Summer was a bit late in arriving this year but it finally came intensely and just in time for the 11th Inter-Ex on the next to last weekend in July in Ostrach/Baden-Württemberg (!) – this is underlined for the sake of the Ostrach inhabitants, because too many participants still think Ostrach is in Bavaria. Ostrach is, however, situated within sight of the Bavarian border. Last year the meeting took place in the Netherlands, this year Southern Germany was the destination. Considering that most participants attend all meetings, the geographical distance is of little significance: they have to go there anyway! When all is said and done, this exchange between North and South is just fair! Sometimes people as Helmuth Siebarth and his Italian crew are closer to Ostrach, the next time people such as Eric van den Hoogen from the Netherlands or Jupp Wimmer from Mönchengladbach are earlier on the airfield in Nederweert/the Netherlands. For the Australian Bob Meyer it should not make a difference to come to either Ostrach or to Nederweert. As he was born in the Netherlands and was on holidays back home, he had to travel the same distance as the traditionally strong experimental-troupe from the Netherlands.

The models
An experiment is hard to define and therefore the models are all very different. It starts with the fun models, (for example the 14 decker of Peter Haas from Berlin). Many small wings generate a lot of drag and mechanicalproblems, but in the end the model flew quite well (to the surprise of everyone). In this category of fun constructions, some also belong to the inflatable “soft models” of Helmuth Siebarth. It would be nice if everyone could use this idea - put a model in a small bag, inflate it on the field - and we are flying! Norbert Schilling takes a totally different path. His models are closest to true experimental ideas: They serve no practical purpose and are just built to test new airplane constructions: His gigantic gyroplane has electric motors at the ends of the rotors, quite extensive electronics in the middle and a balance assembly on one rotor blade. He couldn’t fly because a sideways gust of wind blew the 4m rotor into the ground. More adventurous still, was his rotary roller that unfortunately couldn’t fly either.

Many, many wings and on top of it a Teddybear!!

Flight preparations before, and celebrations after the flight of the “Avion” of J. Wimmer

The “Fliegende Walze” of N. Schilling tries to fly…

Heerlein set himself a hard task: to build an airplane with tilting engines (Kippmotor). He still has many problems.

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Flying like the birds
Fred Ludwig from Chemnitz is well known at Inter-Ex for his flying saurians. His flights are one of the main attractions during the meeting and he has won many cups. His saurians fly perfectly, turn their heads, move the wings during the flight and make appropriate noises. F. Ludwig could be very contented, he is sure to receive invitations for many flight meetings and the applause of the viewers. But he is not a show-flyer but a researching model constructor. He has now confronted the task of flapping wing propulsion now. He has already built 5 such models and, to the surprise of everyone, the lightest model (600g) was not the best flyer. His current ornithopter has a span of 2100mm, weighs 1260g with 3 wingbeats per second. The engine is an AP 29 with 100:1 reduction (50:1 toothed belt drive, 2:1 chain gear mechanism). Fred Ludwig suggested in Ostrach that his model would just fly a few metres, just bouncing along. That’s what it did at first until his bird started his real flight and landed after a long curve, easily flying over a 2m fence and landing in the coffee tent. The damage was small, the success was great. His third model in Ostrach, the “flying plank” looks quite unspectacular but even the experts miss the fact that the planks usually need a fin or winglets. Fred Ludwig is very keen on natural flight, so he doesn’t want his models of birds to have an obligatory celluloid-fin.
He has built a novel steering mechanism into his flying planks: First, he has the normal RC functions, that means the elevator an ailerons are mixed. Additionally, the model has a small “weather vane” with a sensor, that senses any sideslip and send this to the electronics to be converted into servo commands. (The weather vane can be disguised as a feather or similar). The ailerons are operated as spoilers that generate drag. This steering mechanism is very birdlike and the principle allows this sort of plane to be designed in way as to give essentially lower drag and therefore increased performance. It is impressive to see his “plank” in turning flight and how it holds the course when flying straight ahead. We hope being able to report more about his models.

Solar flyers stay at home
Even so the sun was shining in Ostrach more than enough, hardly anyone made use of it. Just one solar flyer participated in the event, Dr. S. Dienlin, who was known for his constructions from this magazine. His NanoSol undertook a duration flight, had no problems with the fresh breeze and was looking forward as well as its constructor to the next task for the Guinness book of records. It is already registered there as “the smallest purely solar driven, able to rise off ground RC model”.

“Double Duo” makes 4 all together. That is also the case when looking at the double tandem of Wil van Loon/the Netherlands. A gliding model with four wings. Or a Canard and an elevator and two wings – as you like it. The ailerons work in the same sense, the fins and elevators work in the opposite sense. Front aileron down means right elevator up. A very nice model, that flies very well: this year’s FMT- cup winner!

Another class of model are the great scale models, but they are also included in the experimental class due to their special features. The Horton flying wing models are not so extraordinary with the exception of the Hortons of Eric van den Hoogen. We do not very often see such perfection in the construction of models. Also worthy of note is Eric van den Hoogen’s flying abilities. Every flight is pure enjoyment! His Horten XII, known from last InterEx, is now equipped with an electronic speed regulator instead of a switch. “Dino” from Schulze is a regulator that is able to cope with the currants as requested (40 cells, 2xRobbe 240 geared together onto a common propeller shaft; own propeller construction, foldable, all to original scale. Cup: “Best Flight”.

 Two with steam
We have known Hans Berndt with his Henson Aerial Steam Carriage from last year at Nederweert. AT that event, the model managed a few minor bounces rather than flying. Many of the competent spectators did not believe that he could steer his plane: No dihedral, the fin mounted behind the fuselage, two big propellers that were installed on outriggers. Everybody thought that the control of the model around the yaw axis should be the problem; the fin being too small and concealed in comparison to the gigantic measurements of the fuselage and the wings. This year, Berndt came with the same model - having a not too much extended fin and a lot of trust in his work. Mr. Henson in his steam engine plane thanked him by delivering exquisite flights. Cup: “Best Technique”.

Jupp Wimmer belongs to the same category. As being one of the people who has been most engaged in Inter-Ex from the very beginning, he builds planes from times when no planes even existed. He constructs according to designs and weird ideas for flying machines that can be found in old books and that were not really able to fly – even so it is sometimes claimed! A man named Clement Uder may have flown that plane in 1889, which would make him the first motor flyer in the world! This is proven by the discovery of tracks of his landing gear in the ground of a parade near Paris. These tracks, it is claimed, disappear after a few metres, then reappear again on the ground. In between making these tracks, he must surely have been flying? Jupp Wimmer found, however, out for sure that he wasn’t. He rebuilt the plane. At its first flight, even before Inter-Ex, the landing gear did actually clear the ground, but the model performed a tremendous backward somersault and hit the ground again. Surely, Clement, sitting behind his steam engine and putting in coals, would not have survived this action. As a consequence, Jupp Wimmer constructed a long, weighty, snout containing a lot of heavy metal to shift the centre of gravity forward. At the Ostrach field, the expert for the impossible, Eric van den Hoogen, took the transmitter’s controls. After a partly quite wild, but nevertheless controlled flight (with a good landing) he admitted to never ever having flown such a terrific plane.
That’s all we can say about just some of the many models at the event. The space in the magazine is limited and so were the cups. We would have had to hand out three or four times the amount available to justly honour all the performances. To those who did not receive a cup this year even if it may have been well earned: Maybe next year in Nederweert?

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