On Tue, 02 Mar 1999 09:18:54 -0500, Tom Rauch <w8ji@contesting.com>
wrote:
>
>
>> Therein the rub... I wonder if the science exists to really manufacture
>> gears to destructive tolerances against absolute maximums, at least for
>> the kind of money we are willing to spend.
>
>
>The problem is the rating method. I can purchase a transmission,
>and know full well in advance how many lb/ft of torque the
>transmission will take in shock load and in steady load.You can
>bet a mechanical engineer would have a good idea how much
>torque would kill a gear box he designed.
Yup, if we're talking about the high end. More inclined to accept your
point on the high-end stuff because of the methods used. Low end stuff
has gear teeth that are part of the casting. I have several of these
and I have the rotor at ground level, turning Masts with TV antennas.
I don't even trust these enough to risk getting on a ladder to fix
them.
>
>All this rotor mubo-jumbo about sq ft is meaningless.
I agree. It is true that some antennas will not be torque neutral in a
high wind. I'm not sure how good the science is for simply computing
this from a listing of diameters, lengths and positions spec for the
antenna. Yagistress pump this out? If so then should be published.
(Although... If everything is tubular aluminum, it is a crude
approximation only marginally better than SWAG. The Boom length,
turning radius, weight methods are quite better.)
This figure is something that can be balanced with some creativity on
the part of the antenna designer.
It is possible a well-designed antenna of 15 sq ft to be
torque-neutral in the wind, and a 5 sq ft poorly designed antenna to
triple the torque at a particular angle in the same wind.
This makes Sq Feet meaningless for wind torque.
Pete wants all the manufacturers to publish the figures. Yea team! How
do we make 'em? Threats of violence, boycott, congressional
legislation? Problem is that fish can hide easier in cloudy water...
>
>Even if the numbers aren't able to interface with antenna ratings, at
>least we'd know how rotor A stacks up to rotor B.
>
>
>73, Tom W8JI
>w8ji@contesting.com
73, Guy
--. .-..
Guy L. Olinger
k2av@qsl.net
Apex, NC, USA
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|