Sunday, December 30, 2007

Introduction to Gliding (part1)

You may ask yourself the question why would someone be interested in flying a glider? Probably every glider pilot will have his own story, but here is mine. I started flying RC with a Gentle Lady (still have it!) and launched it with a bungee. The friend who taught me how to fly RC was a full-size glider pilot himself except for being an exceptional RC pilot. So I was lucky to learn from him to read the air and be able to catch thermals. I built several power models after that, but had not have much luck in learning to fly them and the damage was always very expensive. At that time I started to follow the SA glider community news. The Goodrums produced a kit of a 2m glider which had better performance than the GL I was flying and I acquired one. This model had a fibreglass fuz and veneer covered foam wings but still only Rudder/Elevator control. I also built several larger gliders like a Sagita (2,5m) and others with basic wood building material from plans. By this time I discovered the slope at Volksrust and built many models which could be flown off the slope. Slope flying is still one of the most amazing experiences for me. Flying at the slope also improved my flying skills. Back to Thermal flying, at some stage I visited one of the Highveld Thermal league competitions as a spectator and saw this is what I want to do. The gliders were mostly moulded high-tech models. I started taking part in an entry level thermal competition for 2m gliders which was called G2K. This helped me improve by leaps in air reading and precision flying. As with any competitive environment, I soon realised I need a better model to do better. To improve my model I had to understand some aerodynamic principals and lots of time was spent on research and discussions on the internet. I also took part in the National postal competition which can be done at your own club and is flown 4 times per year. Gliding (slope and thermal) kept me busy for the biggest part of the year or is it all the time I had available.

I later built a Bubble Dancer from freeware plans designed by Dr Mark Drela which was my first high-tech glider (but still only Rudder Elevator Spoiler) for competitions. I used this model to enter in the Highveldt Thermal league successfully for a few years and Nationals. My first ”full-house” glider was also a scratch built of the Supra designed by Dr Mark Drela. I am currently busy to build (very slowly) another Supra and I now own a moulded Supra which was manufactured in Eastern Europe. I have built many other gliders from, discus hand launch, Scale, electric, to many to mention.

I believe one of the aspects that draw me to gliders is the technical aspect in the design and construction of the models. Model gliders are at this stage at the forefront of development in RC. The state of art glider is manufactured in negative moulds from composite materials like Fibre glass, Kevlar and Carbon fibre. The empty model cost in the area of R10000-R15000. The wing profiles have been developed and tested in wind tunnels. The construction techniques have improved drastically in the past decade alone. As an example, the wing thickness of a modern glider at the root is about 20mm for a cord of 250mm and span of 3,4m (Supra). The wing spar which carry most of the load during launch have to be designed to fit in this thin wing. The pull load on the wing is in the order of 50-80 kg during a launch. Another aspect which I find interesting is the programming and set up of the models. With 4 servos in the wing and up to 5 flight modes (Launch, Speed, Thermal, Cruse and Land) which are used to change the camber of the wing and the modern computer radio you are able to take full advantage of all the aerodynamics for better control of your flight path. The best part however is the gliding community. If you are flying a GL or a state of the art model, all are welcome to fly and test your abilities even if it is only to measure your own improvement. It is mostly like minded people who like to share their knowledge and passion for models. I have made so many glider friends over the years due to the fact that they made time to help me, and it taught me to do the same. As you saw from my story above, it is not necessary to have the best and latest equipment in order to enjoy and take part in model gliding.



Wednesday, December 26, 2007

Sunday flying.

Well, the weather on Sunday was absolutely beautiful for flying, and quite a lot of the guys turned up at the field to take advantage of the fine day. Henk se Edge 540. -- from hyper7pro - (?) My Skybolt coming in for a "touch and go". -- from hyper7pro - (?)
-- from hyper7pro - (?) Marius Burger built this absolutely beautiful little plane. The trim flight was a little rough because of elevator over sensitivity. After landing, he cut about 1 cm off the elevator, and the next three flights was awesome! The little engine runs full blast until the tank is empty, and then you do a few slow graceful gliding circuits, and then the landing. This is probably the last post for 2007, so seasons greetings, and a prosperous 2008 to everybody! Last but certainly not least, I would like to congratulate Dirk and Juanita on the birth of their daughter.