Kevlar vs. wire for pull/pull retract steering setup
 

I need to use pull/pull on a retractable nose wheel. The servo is about 5 inches away from the nose wheel streering arms and it is a striaght shot. When the wheel retracts the line stackens. I used braided wire for pull/pull set ups first and it did not take well to being forced to bend about 90 degrees. So then I tried more flaccid kevlar line, which did accept the retraction action better, but still while under construction I notice the ends were becoming worn and only supporting a few strands at the threaded rod with a hole in it that attaches to the clevis at the servo. Have you had similar experiences - how do you prevent this or otherwise make wires work?

Also, I ran out of the supplied copper crimp tube so I used aluminum and then brass, neither seemed to work. I even added CA but the kevlar line still stackened on me. Maybe I am just not crimping it correctly. I did use the technique of threading the line back through twice in the crimp tube.

Thanks for any assistance you can offer.

RE: Kevlar vs. wire for pull/pull retract steering setup
 

My experience w/ kevlar line is 2fold. The first was pull/pull on a super hots. The line frayed where it rubbed the fuse side, and has held for 8 yrs./200 flts. But its because of my second experience that it won't be used again. I used the kevlar to make a lanyard for my sunglasses, and the kevlar frayed and broke in a months time. On my previous pr of glasses, I used braided nylon salt water fishing line. It lays and moves exceptionaly easy, is alot cheaper, and lasted 4 yrs. before a "wrestling incident" w/ my 15 yr old son broke the glasses. Get some braided nylon and you'll be happy. And to fastened it, tie 2 half hitches in it and thin ca the knot. It'll out live your airplane. Bryce

RE: Kevlar vs. wire for pull/pull retract steering setup
 

Yep,

Kevlar is plenty strong enough, and won't stretch, but...
It's not good at all with abrasion resistance. It can fuzz up pretty easily. So, if you have a clear shot for your cables, (not passing through any touching guides, etc..) then it should work well for you.

RE: Kevlar vs. wire for pull/pull retract steering setup
 

Thanks for the replies guys.

ScaleMe

RE: Kevlar vs. wire for pull/pull retract steering setup
 

ScaleMe, Some multi strand wire like the type used in fishing leader material is very supple ("Malin" brand is very good [link]http://www.malinco.com/fishing/boa.html[/link]) you can tie knots in it as well as use crimping sleaves to make your loops. It doesn't fray like kevlar. A less expensive alternative would be very heavy weight monofilament fishing line which is much better at abrasion resistance ( 80 to 100 pound test and greater, use the sleeves to crimp your loops 1/8 in. brass tubing makes good sleaves)

RE: Kevlar vs. wire for pull/pull retract steering setup
 

Thanks Dogisland. Good to know of another option.

ScaleMe

RE: Kevlar vs. wire for pull/pull retract steering setup
 

From my considerable experience with fishing, any monofilament line will stretch. That's why on the sport boats that go for the big tunas, etc. and use 80 to 100 lb. test line, the crew just about insists that you replace your line every night. For me, I'd use twisted steel cable for my pull-pull. I'm currently building a Funaero SE5a and am ustin the cable on my rudder and elevator pull-pull. I've done this in the past on my planes and have not been disappointed yet.

RE: Kevlar vs. wire for pull/pull retract steering setup
 

For pull/pull I found plastic coated braided steel leader in 30' spools at Pro Bass-$2.50 with crimps. Almost identical to Dubro pull/pull cable packs, same diameter and comes in same type container. Works great and price is right.