D O P E R O   3.0

 

Span:
Lenght:
Weight:
Sail area:
Wing load:
3 m
2 m
 0,88 kg
4,33 m²
0.20
 
Wind min:
Wind maxi:
Pull min:
Pull max:
 
Line angle:
Line used:
3,5 m/s
6,5 m/s
1,0kg
12 kg
 
 50° to 60°
polyester 90kg

 

Dopero is the acronym of Double Pearson Roller. Starting the history is the Roloplan, a kite built in the 1920th by the German company Steiff. After the Second World War, this kite was no more available, but a British kiter, Alexander Pearson re-designed this kite. The larger main sail added pull, the aft sail was reduced without loosing stability. This new assembly is easier to set. He named his kite the Roller. Nowadays it is often reffered as Pearson Roller.
In the 1990th, a fine German kiter and kaper, Ralf Beutnagel wished to combine the ability of the Roller with more pull, and to give it more sail area, he had the idea to design it with two longitudinal spars. The Double Pearson Roller was born. He named it Dopero.
I have choosen this size because the pull is sufficient in 4 to 5 m/s winds, and for wind speed under 4 m/s I have the Crico 3.6 which is more efficient.

 

This kite has a low wing load ratio (weight/surface), giving it low wind flight ability. As a flat kite, like the Rokkaku, it has almost no drag, and is flying with a high line angle.
Its drawback is the miss of a keel. It may happen in some circumstances that it slides far on a side and do a loop, or even worse, go for a dive. To prevent this, a kite need some drag, and some keel effect. Some kiters have added keels, or funnel shaped sails, or drogues. But none is satisfactory.
For this reason, I have designed a double vane keel, which is more efficient than a normal keel. It adds a little more drag, but not as much as a drogue, so it keeps flying at high angle. Then, the angle between the two keels gives the maximum efficiency of a vane, and force the kite to keep its orientation in the wind.
 
Roloplan Stieff

 

 
right keel