Gentle Lady (oz5961)

About this Plan

Gentle Lady. RC sailplane.

Quote: "As a novice glider pilot. Carl wanted a two meter ship that was respectably efficient, and, if possible, competition worthy. RCM feels the Gentle Lady meets that criteria - Like most people who like airplanes, I've always been drawn to sailplanes. They are the most beautiful of man made birds. Their sleek lines, high aspect ratio wings, utter cleanliness, and refinement ot detail make them the ultimate 'clean machine.' At the Toledo Weak Signals show each year, I have to stop, study, and admire the very appealing sailplanes that are always on view.

Naturally enough, when thinking of designing one myself, I studied some of the better known ships around. Among them were the Pierce Arrow (oz6214), Wanderer (oz4100), Soar Birdi (oz10400), Drifter II (oz572), and others. One of these was a fine US East Coast design by Woody Blanchard, which has done well there. In addition, I spent many hours talking to glider flyers, reading magazine articles, newsletter reports, etc. There was a lot to learn.

Totalling things out, this is the design philosophy that emerged. First of all. I decided I wanted a two meter ship. The essential reason for this was a desire for simplicity. Getting into one of the larger birds, I felt, would tend to draw me into complications. They just naturally tend to be a little more sophisticated. Also. I had noticed growing general interest in the two-meter class. Interestingly, I later learned that the Dassel, the Austrian design that has aroused such great interest world wide, and which was used by the new world champion. Anton Wackerle, has only about 6in more span.

Besides simplicity, I wanted the ship to be easy to fly, and stable. Obviously, as a novice glider pilot, I didn't want to shoot for more efficiency through means that might require some real flight skills.

At the same time, I definitely wanted a ship that was respectably efficient, and, if possible, competition worthy. One major means of achieving the efficiency sought, based on past experience, was to use a thin airfoil, and build it with a smooth top. The lift-drag ratios of such airfoils tend to be quite high, and it turns out the Gentle Lady can really 'cruise' when desired.

Further, in addition to keeping the model lightweight, I felt it desirable to have generous wing area to reduce the wing loading, and help pull up the weight of the tow line, whether hi-start or winch. Despite having what appears to be a large chord, the aspect ratio comes out at 9.3, which compares not too badly with the Dassel at 10.6. In addition, the stabilizer does provide a slight amount of lift, not just drag. This is proven by the location of the Center of Gravity, which is around 40% back.

Lastly, I wanted no projecting wing dowels, or rubber bands crossing over the centre of the wing, After all, why disturb the airflow? When you get right down to it, a glider has no means, such as an engine, to make up for a lack of efficiency. All it has to help it stay up is cleanliness. The dirtier it is, the quicker it will come down..."

Update: added review from Spanish magazine, RCModel (No. 160/1994), thanks to alcalaino.

Supplementary file notes

Article pages, text and pics.
RC Model review, 1994 (in Spanish).

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