[RE-wrenches] Whisper 500 service

[Ross Taylor]

Hi Nathan, thanks for the update after your site visit.  Instead of
emailing you directly, I'm responding here in the hope this info might be
of help to others (now or in the archives)  See my responses (some more
helpful than others, I'm afraid...) below, after each of your questions:

-          Shock absorber appears in good shape other than the blown out
polyurethane bushing. I can easily find complete replacements for the whole
shock absorber, but haven't found anyone selling just the bushing, you
wouldn't have any ideas where one could find that?

Sorry, no help on this.  I don't have any specs on that bushing, such as
the durometer rating.  But, I don't think the specs are particularly
critical so (hopefully) you can find something at the auto parts store.

-          The SOOW cable coming from the brush assembly is cracked in
several spots (picture attached.) Any chance for a field repair on this or
replacement assembly from somewhere at this point? Or am I better off just
sealing it up the best I can? The actual wires appear fine, just the outer
layer is damaged.

This cable should be connected, at each end, with standard wire nuts.  If
you cannot wrap it, to protect the inner conductors, it should not be a
huge deal to replace it and the cable itself should be available at any
electrical supply house or even a big box store.  It's got 3 conductors. At
one end, it's connected to the alternator output wires (grouped according
to voltage configuration) and at the other it's connected to the three yaw
brush wires.  It should pass through a watertight cord grip fitting at each
end.

-          The blade edge tape is basically intact except for a couple of
inches of hanging flap, which the customer has told me has been that way
since the original install. How bad does it have to get before you would
worry about it? Any source for replacement?

That tape should be a 3M polyurethane protective tape, also called blade
(or helicopter) leading edge tape.  I did a quick search on Amazon and
found some similar products, but they aren't cheap.  About $25 for a 2-inch
by 12-foot package.  But that's par for the product.  The leading edge tape
isn't really critical except in areas where the turbine blades are
impacting hail, freezing rain, etc.  Or, in Vietnam...  but that's another
story.  I don't think I should post directly links to sales here, but if
you search for "amazon helicopter leading edge tape" you'l find some.

-          This is a 48V system. Turbine wiring is confirmed correct,
battery wiring is correct, but the diversion load is wired differently than
in the manual. The diversion load is 4 ea. 0.75 Ohm resistors, looks like 2
x 2 series/parallel. It looks like the original installer removed the
factory dump load wiring and installed their own. Do you have or know where
I can find a more detailed wiring diagram for the diversion load? The
manual is a little vague and doesn't anywhere show the actual diversion
load wiring.

First, did you check the DIP switch settings on the controller card too?
 That's one of the three configuration locations, plus the turbine
alternator wires and the diversion load.  Can you email me, directly, a
photo of the diversion load?  The manual is, indeed, vague.  Having said
that, though, this is the least critical of the three settings.  And if the
customer hasn't burned up the controller so far, it's probably just fine
and not worth changing.  The two indicators of improper configuration are
either a burned controller or diversion load (if those are set too low
compared to the voltage configuration of the turbine).   For example,
having the turbine alternator wiring set to 48 volts but having the
diversion load and/or controller set to 24v.  In this case, you'll get good
low-wind-speed output.  But you'll burn something in the stronger winds
when they occur.  And, they will occur.  On the other end, a complaint or
observation that the controller only shows a green charge light in very
high winds, could indicate that the turbine alternator's set to a low
voltage compared to the controller.

Thanks so much Ross, it is really generous of you to answer being off of
the SW payroll as it were. If you find yourself in Fairbanks, Alaska
anytime, give us a call and we'll show you around and take you out to lunch!

All best,
-Nathan
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