----- Original Message -----
Sent: Wednesday, March 07, 2001 3:48
PM
Subject: Re: [COUPERS-TECH] Elevator
Cable Tension
----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
'Coupers,
I have been watching this cable tension
discussion with some interest. I have over 16 years of experience
rigging flight controls on Heavy Aircraft with the Air Force. With the
exception of the Air Refueling Boom control cables on a KC-135 (250 lbs) I
can't think of any cables (flight control or other systems) that are higher
than aprox. 100 lbs as measured on a tensiometer. In fact most of the
flight control cables that I have worked with have been right in the 100 lbs
range.
If I understand the principles of cable
tension correctly it seems to me that if you hung 100 lbs of weight on a
single cable then measured it with a tensiometer it would read 100 lbs.
If it is a 2 cable system like most of our closed loop systems on flight
controls are then a 100 lbs weight would measure only 50 lbs on each cable for
a total of 100 lbs of force on the system. That would mean that if I
were reading 100 lbs of tension on a closed loop cable system then you
are actually pulling the two ends of the system together or towards each other
at 200 lbs of force.
I don't recall what the tension was that someone quoted for the 'coupe
but it seems to me that if it said 150 lbs of force on the system then
the cable tension reading on a tensiometer would only be 75 lbs. not 150
lbs. 150 lbs on the tensiometer would equal 300 lbs of force on the
bellcranks. I have a hard time believing that the 'coupe is suposed to
be any higher than 50 to 75 lbs as measured on a tensiometer. I could be
wrong but that is my 2 cents worth.
As a side note Advisory Circular 43.13-1B
ACCEPTABLE METHODS, TECHNIQUES, AND PRACTICES--AIRCRAFT INSPECTION AND
REPAIR CHAPTER 7. AIRCRAFT HARDWARE, CONTROL CABLES, AND TURNBUCKLES is
a great resourse for cable info.
Mavin Jones
MSgt USAF
----- Original Message -----
From: Jim Read <[EMAIL PROTECTED]>
To: Coupers Tech
<[EMAIL PROTECTED]>
Sent: Friday, February 23, 2001 5:31
PM
Subject: [COUPERS-TECH] Elevator Cable Tension
>
----[Please read http://ercoupers.com/disclaimer.htm before following any
advice in this forum.]----
>
> We're talking tension here, not
pressure and it seems that most of the
>
> respondents that have
done this job have elected to use a lower figure
>
> than the
book. For the job in hand I consider the tension called out
> to
> be high. I have no scientific evidence to back up this opinion,
just
> experience with other types. I'm also aware that we get
down to 32
> degrees here at VNY and that internal hanger temperatures
often get
> above 150 degrees in mid-summer. Like our Canadian
friend suggested,
> sticking blindly to the written word and ignoring
instinct and
> experience is contrary to good practice, which is the
basis for the
> advice I originally sought. I'll let you know
what we decide.
> many thanks.
> jim
>
>
>
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