Esprit. Radio control sailplane model.
Quote: "These words from the poem 'High Flight' written 30 years ago by an American trainee pilot, best described for me the thrill of R/C sailplanes. Those of you who have flown sailplanes know and understand the emotion and challenge resulting from the world of silent flight. To them and to those modelers who have not yet tried this exciting sport, this article is dedicated.
My involvement with building and flying model airplanes goes back to the time High Flight was written. I have enjoyed all phases of this hobby including Indoor Flying, Control Line Speed and most particularly Wakefield competition in the late 1950s. Nothing has provided me with the satisfaction derived from RiC sailplanes! The challenge is infinite. The variety of models and tasks is limited only by the imagination and daring of the flier. No matter what you are flying now - or if you are a newcomer to R/C modeling, I urge you to try R/C sailplanes. Once you do I believe that you will share my enthusiasm.
While there are many excellent kits available for those who find the convenience necessary, only by designing and flying your own ship is total involvement possible. The model presented here is one persons approach to the ultimate goal of flying higher, longer and farther than anyone else.
The Esprit is a high performance sailplane designed around modern two channel miniature proportional equipment. With a wing span of 84in, it offers competitive performance with convenient size. The plug-in wing panels and removable tail group provide convenient packing for traveling to contests or the local field. It is in the air, however, that this bird belongs. And your first flight will prove that this model was worth the time spent in the shop.
Esprit's most significant characteristic in the air is precise and immediate response to your command. She will fly smoothly, hands off, trimmed for straight flight or an open thermal hunting turn. Once she finds lift you can bring the nose around in a tight flat turn without excessive banking or danger of side slipping. She is equally responsive to pilot control which makes spot landing a cinch - just fly her into the final approach and tap downwhen you reach the spot. The normal glide speed is medium-slow, but somewhat faster than expected from this type model. By feeding in a little down trim she will move right along and cover a lot of sky quickly.
The Esprit design objectives were to provide a lightweight model with minimum drag. With an equipment weight of approximately 7 oz and a desired wing loading of 4oz/100 sq in, an area of 500sq in, and flying weight of 20oz were selected as basic design parameters. Previous experience has shown that an airframe weight of 12 to 14 oz was achievable with a 500 sq in sailplane if carefully built and finished.
The heart of any sailplane is the wing since this provides the total lift and major drag of the model. The tail group provides longitudinal and yaw stability while the fuselage houses the radio and ties the whole thing together. Since the wing plays such an important part in overall flight characteristics, it must be the focal point for design... "
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