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Date: Wed, 06 Jun 2012 08:28:19 -0400
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From: "Dan Schaefer" <dfs155@roadrunner.com>
Subject: Re: [LML] Hydraulic vs. electric CS props
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Gary, I've been using a MT electric C/S prop for the last 800+ hours in my
early Lancair and find it to be quite smooth and reliable.

There are pluses and minuses with either type prop (hydraulic vs electric)
so you pays yer money and takes yer chances. Personally, though I come down
in favor of electric for my Lancair, it does have a couple of negatives that
you should consider.

First, the electric installation is probably somewhat lighter as it doesn't
use a hydro prop governor, associated oil lines and control rigging. The
electric system does use a slip-ring, brush-block and controller but I doubt
they weigh much more than a pound altogether (didn't weigh mine - just an
eyeball guess).

The two negatives I can identify for the electric is: 1. It has a somewhat
slower response than a hydro - you have to learn to bring the power in a bit
slower than you can with a hydro or the RPM can get too high but that's easy
to get used to. 2. If you lose all electric power on board, you're stuck
with the pitch setting you have. I'd guess this could be addressed by a
small aux. battery for the prop system with an isolation diode (a few 
amp-hours
would likely be sufficient as the motor in the prop draws an amp or two, 
intermittantly)
though this could negate some of the weight advantage.

The related plus for the hydraulic prop is that it would keep working as 
long as
the engine was running - and producing oil pressure, of course.

Another small thing on the MT electric is the need to find some panel space
and depth for the controller.  If using the MT P-120-U controller, the 
faceplate
needs about 3.8 x 1 in. with about 7.5 inches behind the panel, including 
the
connector.

One last thing - MT has some very good service centers out there - and some
not so good. In order not to be sued, be glad to give you an ear full off 
list if you
go with MT.

My two cents worth.

Dan Schaefer