How Bad of a Line Kink or Bend Is Dangerous to Fly?

[Kafin Noe’man]

How severe does a line kink need to be before it becomes an issue?
I have attached the picture as well.

So far, it doesn’t have any fray or whatsoever.

And what’s the difference between a bend and a kink on the lines?

[Ken Culbertson]

Those do not appear dangerous.  As long as the bend is rounded like yours are they are OK to use.  What you don't want to do with those small bends is try and straighten them by hand.  Normal pull will straighten them enough in flight.  Bending them back will weaken them.  If the kink is tight or it starts to fray, even one strand, then those nice 65' lines just became 60'.

Now let me add a caution.  Although safe to use they will start to act a bit springier.  Sort of like a cable handle with too large of loops. I know you are getting better quickly and will start to notice these things soon if you are not already.

I will leave it to Howard to describe what a still safe set of Combat lines might look like!

My 2 cents - Ken

As for the difference, a kink will show strand separation, usually at the peak.  A bend will not.  A fresh kink is not reason to go home but it will start to corrode or rust internally so you should dispatch it by either shortening the lines if close to the end, or replacing them soon.

[Colin McRae]

IMO those slight radius bends or 'kinks' don't look too bad. For the kinks that are more of a hard right angle, I would look at them under a magnifying glass to see if there are any deformed individual wires or frays. If not, pick up one of these tools that can be used to straighten out soft kinks or curves. After straightening, you can also pull test the lines for piece of mind.

If ever a hard right-angle kink, I would not use the lines. Always be on the conservative side to protect your models.

https://www.dubrofishing.com/products/small-wire-straightener

[Kafin Noe’man]

Thanks, Ken and Colin, for the detailed explanations! That makes a lot of sense.

I’ll leave the bends as they are and let normal flight tension work them out rather than trying to straighten them manually.

Also, I appreciate the clarification on the difference between a bend and a kink.

Thus, is it safe to say if:
[  ] A kink is when the angle is about 90 degree or less — definitely need to replace it.

[  ] A bend is when the angle is still in between 120 and 180 degree — not ideal but still safe to use with cautious (keep an eye out for any strand separation as a warning sign).

 Thanks again for the insights!


Best,
Kafin

[Doug Moisuk]

PULL TEST THEM.

[Steve Helmick]

Thanks, Ken and Colin, for the detailed explanations! That makes a lot of sense.

I’ll leave the bends as they are and let normal flight tension work them out rather than trying to straighten them manually.

Also, I appreciate the clarification on the difference between a bend and a kink.

Thus, is it safe to say if:
[  ] A kink is when the angle is about 90 degree or less — definitely need to replace it.

[  ] A bend is when the angle is still in between 120 and 180 degree — not ideal but still safe to use with cautious (keep an eye out for any strand separation as a warning sign).

 Thanks again for the insights!


Best,
Kafin

It has nothing to do with the angle of bend, but the sharpness/radius of the bend. Personally, I would manually straighten
the lines in the picture and give them a good tug before flying. Flying with extra springy lines won't help you fly better, and I think most of us are always trying to do that!  Steve

[Paul Taylor]

You should see some of the combat guys lines. Looks way worse than those. But then most combat guys are like honeybadgers. Look those up on youtube.

But my saying is when it doubt throw them out. I put too many hours into building a plane and would hate to lose it over a consumable like lines. Then there is the safety factor.