[CCF] Fwd: [CQ-Contest] Question regarding crank-up tower feedlines

[Jukka Klemola]

Niille jotka tekevät itse omia systeemejään, tässä ehkä jokin uusi idea.


---------- Forwarded message ----------
From: VE2TZT
,,,
So, after several tries I finally found the solution. It will be faster

to explain it with pictures so have a look at the following link :

https://drive.google.com/file/d/0ByGzx2yN6nC3QzY0clpyUmtoV1E/view?usp=sharin

...
First I did a scale 1:1 simulation of the top of my tower to determine

the length and path of the cables when the rotor is moving on 450 deg.

That reproduction had also helped me to write a procedure to install the

DB42 on the tower. You can "run the movie" in both directions my pushing

the arrow keys.

A Second part shows how I have attached the cable on the standoffs. The

very important thing is that with the numerous moves up and down that

you will do, if the cables are bonded directly to the standoffs the

cables will be bent with a too small bending radius and are going to

break by metal fatigue. So to keep the cable out of the minimum bending

radius I invented a simple system consisting in attaching the cables on

small metal plates which are rotating around the standoffs. That way the

cable and plates are articulated and are rotating while the tower is

retracting respecting a loop shape.

Third, you must arrange the cable loops in a way they cannot pass into

each other neither pass around any standoff. Otherwise you will live

catastrophic experience of teared out cables and standoff. On the last

pictures of the pdf, as for the rotor simulation you can "run the movie"

of the tower retracting and observe how the cables are turning from a

straight line to loops while retracting.


Then in any position of the tower you have a clear tower and never the
cable will lay on the ground.

Enjoy

Gilles VA2EW / VE2TZT