2PES

2PES - 2 Point Exponential System
Another cool Madstab actuation system is the 2PES by Stéphane "pgts" Combet of France. This is another sort of hybrid pushrod system, which uses round movement on the servo arm, combined with spring tension and a pushrod, to gain mechanical exponential and provide 180º surface rotation.

The pushrod is with two forks linked to 2 vertical axis mouving round on the servo. The spring tension provides there is always one fork on one vertical axis. 2PES is based on the fact that linking pushrod with 0° instead of 90° leads to a very slow displacment around neutral. The displacment speed grows up when the servo arm aways neutral.

This system has been designed for gliders heavier than LeFish Light, needing something stronger than what ultrabatics need. The glider it was designed for is about 1.4Kg and 2m50 wingspan. 2PES is realy good around neutral, precise and strong. But it needs a little bit of place in the fuselage. I still need tries to say more about flying. On very big gliders this system could be used with big radius on servo arm (like 40mm) and medium radius (like 20mm) at elevator arm to obtain 180° surface rotation with strong mecanical exponential.