I upgraded the school electric winch (the MoonRover) while waiting for the weather to improve. If the video does not kick in on this page, watch it on YouTube
I also made modifications to my SP but the weight distribution was not what I was expecting using the half hour battery. The motor was moved about 6" closer to the frame. I though that it would be distributed sort of close to what a gas tank load would be but not. It spun the blades with the motor, all was working fine at low RPM, but the blades came too close to the back of my helmet. Oddly, the net started vibrating in a strange way due to the vacuum behind the prop. Too many cons, so I went back to default.
Phil,
Do you know what the average ratio of pay-in towing length to height achieved is? If I invested in something with 1000 meters of line, how high could you get a pilot before he is at the apex for disconnect?
4000’ of lines.
On paper you can tow half the distance of the line in zero wind speed and no natural lift or 2000’
Many variables involved: wing angle of attack, tow trajectory, gust factor (thermal or otherwise), towing force (most important) because a tow operator without proper towing skills could endanger the pilot if the wing goes into a lockout (most dangerous part of towing with a static system). It is advised to have a line tension gauge of some sort to let the tow operator monitor the tension and adjust it accordingly to avoid entering a lockout. A lockout is when the wing wants to go up (high angle of attack) but the line is pulling it down while rewinding. The two forces fight each other to the point of where the glider unable to climb anymore, will only release the tension by diving right or left and accelerated toward the ground. Towing is a specialty which must be learned as anything else under the supervision of a knowledgeable tow operator.
Thanks Phil. Yes, I understand lockout. I was considering building one that is remote control so the pilot can remotely control the tow. Presumably with electric one can set the max tension by setting the max current and it would slip or shut off if load is too high. I have a beach near me where they won’t allow “motorized vehicles”, and they define PPG as a motorized vehicle. Was thinking I might get away with electric tow.
My winch is radio controlled. You will need a drogue chute. Something to be very careful about is the line drift once it has been released. Gusts can easily drag your line where you did not want it to go (power lines, roads, building, tree lines, etc… Also, if your system experiences a hard shuts off, you may experience a surge, and it is something to anticipate and know how to manage. When tow mu students, I always decrease the line tension to minimize the surge upon pulling on the quick release on their end.
