Hi Glen. Couple of questions surrounding the effect on the pedals in a hydraulics failure . 1. Does the accumulator associated with the yaw load compensator function in a different manner than the accumulators on the cyclic? i.e. When an initial failure occurs the cyclic is going to feel the same , so what is different with the accumulator linked to the tail rotor? i.e is it filled with a fluid rather than a gas , or is the yaw load compensation system pressurised mechanically via the pedals ? 2. When the hydraulics fail and the heli yaws left ,is this because there a denigration of anti torque or an increase in torque reaching the rotor system causing a left yaw ?
Hello Dave. I have made a video on this subject... th-cam.com/video/UBEk-_K5Vac/w-d-xo.html The accumulators on the main servos are the same design as the accumulator on the yaw load compensator. Its a metal container with a rubber bladder on the inside filled with nitrogen. Hydraulic fluid is pumped into the container and collapses the bladder. The bladder is then trying to push fluid out. On the main servos when there is a hydraulic failure the accumulators push fluid into the main servos to give hydraulic boost until they run out of fluid (an entire other long discussion about how servos work). Once the accumulators are depleted on the main servos there is no more pressure available and the controls no longer have hydraulic boost. The yaw load compensator is a closed system. The accumulator on the yaw load after a hydraulic failure pushes fluid into a chamber in the yaw load compensator to induce twist into the spar of the tail rotor . When returning the pedals to the neutral direction the twist in the spar helps you push the fluid back into the accumulator. To answer your question regarding yaw to left. You are referring to training I assume. When I create the hydraulic failure in training I depress the HYD TST (ACCU TST) pushbutton which reroutes pump pressure back to reservoir and dumps pressure out of yaw load compensator. So during training you do not have a yaw load compensator (there is a way to get it back before you switch cut off but this just confuses pilots so we have you do the landing without yaw load... at training weight the forces are the same at high weight with yaw load.... kinda a whole other conversation). Since you lost the compensator at the beginning of the training failure the twist wants to come out of the spar on the tail rotor. So your pedals move and you do not stop them. Did I answer your questions?
Hi Glen. Couple of questions surrounding the effect on the pedals in a hydraulics failure . 1. Does the accumulator associated with the yaw load compensator function in a different manner than the accumulators on the cyclic? i.e. When an initial failure occurs the cyclic is going to feel the same , so what is different with the accumulator linked to the tail rotor? i.e is it filled with a fluid rather than a gas , or is the yaw load compensation system pressurised mechanically via the pedals ? 2. When the hydraulics fail and the heli yaws left ,is this because there a denigration of anti torque or an increase in torque reaching the rotor system causing a left yaw ?
Hello Dave. I have made a video on this subject... th-cam.com/video/UBEk-_K5Vac/w-d-xo.html
The accumulators on the main servos are the same design as the accumulator on the yaw load compensator. Its a metal container with a rubber bladder on the inside filled with nitrogen. Hydraulic fluid is pumped into the container and collapses the bladder. The bladder is then trying to push fluid out. On the main servos when there is a hydraulic failure the accumulators push fluid into the main servos to give hydraulic boost until they run out of fluid (an entire other long discussion about how servos work). Once the accumulators are depleted on the main servos there is no more pressure available and the controls no longer have hydraulic boost. The yaw load compensator is a closed system. The accumulator on the yaw load after a hydraulic failure pushes fluid into a chamber in the yaw load compensator to induce twist into the spar of the tail rotor . When returning the pedals to the neutral direction the twist in the spar helps you push the fluid back into the accumulator. To answer your question regarding yaw to left. You are referring to training I assume. When I create the hydraulic failure in training I depress the HYD TST (ACCU TST) pushbutton which reroutes pump pressure back to reservoir and dumps pressure out of yaw load compensator. So during training you do not have a yaw load compensator (there is a way to get it back before you switch cut off but this just confuses pilots so we have you do the landing without yaw load... at training weight the forces are the same at high weight with yaw load.... kinda a whole other conversation). Since you lost the compensator at the beginning of the training failure the twist wants to come out of the spar on the tail rotor. So your pedals move and you do not stop them. Did I answer your questions?
@@EUROSAFETYTRAINING yes all makes sense now. Thanks Glen
You practice by switching off hydr switch or for practice purpose press accum and after 5 sec depress