[TowerTalk] Prop Pitch indicator.

[Jim Thomson]

I have a prop pitch rotor I got from another ham but has no
provisions for direction indication.


I've heard about selsyns but I believe they require gearing to couple
to the mast. His setup didn't have anything like that and I don't want to go
that route, anyway.


How do I sense the direction ?   I have thought about wrapping the mast with
something like a bar-code indicator as they do for digital readouts for CNC
machines but am in the dark there.


Any suggestions ?




Roger

## selysn's are a pita, history, don't even go there.     Here's a better way.  http://www.k7nv.com/proppitch/

http://www.k7nv.com/proppitch/id37.htm   scroll to the very bottom to see the rotating magnet. 

I have one of these small  K7NV  PP rotor's. [weighs 45 lbs and has 1250 ft lbs of torque]. 

I also have the Green heron control box for it.  That entire combo runs very smooth.  Mine was the
older RT-20  control box.  Jeff  @  GH  sent me the new processor chip,  and I just plugged it in 2 x nights
ago,  so it now becomes a RT-21.   The K7NV  RT-20/21 is not the regular RT-20/21.    The K7NV  GH  PP box has
only one voltage available..for operating the small PP.  [ 27 vdc under load of 9A, as measured at the back of the
GH box.]    He uses  Hammond  25 vac CT  @ 10 A  CCS  xfmr inside it. 

2 x small conductor's used for the pulses   from the spinning magnet.   This results in .1  deg readout on the
digital display. With the GH box,  you also get ramp up/down, plus  min/max speed options.   It's  point and shoot.
With manual control, you still  get ramp up, but abbreviated ramp down.   The mast clamp is deluxe, the best yet,
but they will  handle one size mast only.  

I would suggest you read through the entire K7NV PP  data, as it will save you a lot of grief.    I had another small PP
back in the mid 70's..and ended up getting water in it...toast.   The ramp up/down feature, plus speed control will
save a lot of wear and tear. The .1 deg digital readout is just  icing on the cake. 
 http://www.greenheronengineering.com/    check this out.  Bear in mind the RT-21 used for the small PP is 
not the same as  a regular RT-21.   The K7NV PP's  have a weep hole in the very bottom.  He has also plugged
holes that need to be plugged, and left other holes open for drainage.  That splined, custom mast clamp  works
very good.  Zero backlash anywhere.

IMO, the combo of the rebuilt K7NV PP  + deluxe mast clamp  + GH control box is unbeatable.  Globs of torque,
and a nice 0-9  ramp up/down feature.  It's like having a 9 x speed  automatic transmission in a car...except this
one works on slow down too !  

Later... Jim   VE7RF