OK, I see mentioned on most rotors... specs like "start up torque" and
"running torque" and also "stall torque"
I also notice on most rotor's, the start up current is 2-4 times the operating
current. The OR-2800 has a start up torque spec that is
slightly higher than the running toque. [3200 in lbs vs 2800 in lbs for the
older AC version]. The DC version has similar ratio specs.
Then we have the HDR-300 and ham-4/5 rotors that spec stall torque only.
Then we have prosistel rotors.... whose start up torque is exactly
double their running torque. And why are "in lbs" used at all ?? Why
not just divide by 12 and obtain foot lbs....that I can relate to.
800 in lbs might sound great on a ham-4.... but it's only 67 ft lbs..which is
not very much at all.
I can sorta understand maybe..perhaps the concept of start up torque being
slightly higher than operating torque..for abt all of 1-3 seconds max.
The stall torque figure sounds flaky too. Run the rotor in a test jig with a
1-2' torque wrench attached to it... and let it freely rotate till it hits
a solid concrete wall... then watch the torque wrench wind up...and stall.
Sure you have max torque... you also have zero rpm on both the rotor's
mast shaft..and also the motor itself.
Are rotor makers trying to sell us a bill of goods with BS specs ? IMO, if
you can't rotate once or twice a year because of extreme winds.. who cares.
However the braking sytem has to be able to handle the ant at rest...in a high
wind...which I think is more important. While on the same subject... why
aren't any of these various yagi's ever using torque compensator "plates" or
..."sails" ? They are easy enough to implement. I suggested to Mark @ F-12
that one or more of his superb ele to boom brackets simply be flipped 90
degs... and oriented vertical,,and used as a torque compensator. His are
and only the thinner 1/8" brackets are required. He agreed, it's a cheap
and easy way to add torque comp to any F-12 boom...since he has loads of em
Once riveted to the boom... they are not going anywhere.
Later... Jim VE7RF
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