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General control line discussion => Open Forum => Topic started by: Chris_Rud on June 22, 2015, 08:08:45 AM
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A few nights ago I was getting the 293rd flight on the new typhoon I finished a few months ago. Unfortunately the new Kaz handle cable snapped. I had only used it for a few months and with the green coating it makes it really hard to see if there is an issue. I have emailed Kaz to let him know about the issue and he is sending me a new hard point handle. I'm posting this so that anyone who has a Kaz handle to look at the green cable he is currently using. I have used Kaz handle as long as I have been flying competitively and never had an issue with this handles. As I told Kaz its a great product and I will continue to use his handles with a different cable. A lot of top guys use them, Derek Berry, Bob Hunt and many others and I haven't heard of this issue but I thought I should just let people know so they don't have a bad day like I had.
I'm going to be ok for the NATS since my backup plane is in primer so I believe I can have it completed in time... but it will be tight.
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This is so terrible!
What does the cable rest on inside the handle? Something had to cut through it as it worked back and forth.
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Sorry to see and hear that Chris. That plane flew so well with you at that handle. Glad I got to see it cut through the pattern.
dang.
Shug
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Auuuuggghh! No! So sorry Chris. There are never any good words for times like this.
I've used both Kaz hardpoint and cable handles both, a lot. I don't think anyone put more flights on theirs than Bill Rich, and he had the flying callouses on his hands to prove it. He wore and changed his cables out probably every year but inspected them constantly by pushing a little slack out the backside of the handle to inspect the part that goes around the bend. That is where you will find them start to fray and strands break. I was walking him out to practice one day and by habit was inspecting his handle, and it was hanging by 2 strands... he was very happy I caught it!
All that said, I have a new'ish Kaz handle with the fangs like yours I've never used, still in the pack, and it doesn't have the green coated wire, and I don't remember any I've ever had in the past come with that either... must be something new. The only handle I ever remember seeing with a coated wire was the infamous Windy handle, that failed a lot just like your picture too.
I'm glad Kaz is standing behind it, and I'd really like to know when you get it, if it has a coated cable or bare this time.
Hope you get'er done in time and she's even better than the last one!
EricV
PS: Doug - The wire just goes around a tubular post inside the handle, no hard angles, the exit holes are chamfered if I remember right. I never had one break at the exit, only fray around the internal tube bend inside.
I think this is a case of not being able to inspect a smaller wire because of the coating, and the smaller wire fatigued sooner too... (just a guess that the wire is smaller, it would have to be, to go through the same size exit hole with the coating over it).
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That sucks Chris!! I'm sorry to see that happen! When I was using Windy handles, I had the cable in the handle break after 75-100 flights on my Trivial Pursuit a few years ago. Since then I've gone to hardpoint handles and never looked back. I know a bunch of people who use the Kaz cable handles a lot, and I've never seen one fail.
Hope you can get the new plane done in time!
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I do all of the pull tests on Circle 3 at VSC each year. This year I had one failure and it was also in the vinyl-coated cable. I have no idea what the brand of handle was, only that the vinyl coating makes it impossible to see broken wires in the cable until the cable completely fails.
I suggest that this sort of wire NOT be used, and if you have a handle using it that you take the handle out of service until the wire can be replaced with something better.
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Chris,
Sorry about that loss. It's really unfortunate.
I gotta tell ya Chris, your Typhoon and one other model, can't remember the builder of the other model, but it really inspired me to take that Mig-3 and this Stuka I'm building to the next level.
I saved your photos in a file called, "Great detail."
For those modelers that probably haven't seen your Typhoon, I'll Post these great shots again.
You have the ability and I'm sure the Typhoon will look as good as new again.
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So the handle had 293 flights on it total? That's pretty alarming.
I hate to see the plane crunched, it looked like a great one.
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I do all of the pull tests on Circle 3 at VSC each year. This year I had one failure and it was also in the vinyl-coated cable. I have no idea what the brand of handle was, only that the vinyl coating makes it impossible to see broken wires in the cable until the cable completely fails.
I suggest that this sort of wire NOT be used, and if you have a handle using it that you take the handle out of service until the wire can be replaced with something better.
Very similar cable is sold as deep-sea fishing leader, and it's about as reliable as any other. It might actually last longer than the 1/16 bare aircraft cable we used to use. I have seen a few cases where there was a clear soft spot it you tried to flex it indicating that most of the strands were broken, but you can't see the strands all loose like you can with bare cable.
Unfortunately there doesn't seem to be any real cure for the problem. If you use a cable handle, you just have to inspect it before *every single flying session* and carry the necessary repair bits with you in your tool box.
Brett
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Unfortunately there doesn't seem to be any real cure for the problem. If you use a cable handle, you just have to inspect it before *every single flying session* and carry the necessary repair bits with you in your tool box.
Brett
Yes there is, heavier cable. I have, KNOCKING ON WOOD VERY LOUDLY, 2 bar handles that have cable on them since 2000. They have been the two handles I have primarily used from plane to plane year after year and in all this time I have only seen one strand that was broken and it was not at the bend where it goes through the bar. That same little strand has poked my fingers many times with inspecting the handle. But I have not seen any more. I got the cable from Elliot’s hardware store and it has held year after year. During the earlier years it was 100s of flights year after year. I still constantly inspect because I keep expecting the fray to start but it hasn’t.
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Yes there is, heavier cable. I have, KNOCKING ON WOOD VERY LOUDLY, 2 bar handles that have cable on them since 2000. They have been the two handles I have primarily used from plane to plane year after year and in all this time I have only seen one strand that was broken and it was not at the bend where it goes through the bar. That same little strand has poked my fingers many times with inspecting the handle. But I have not seen any more. I got the cable from Elliot’s hardware store and it has held year after year. During the earlier years it was 100s of flights year after year. I still constantly inspect because I keep expecting the fray to start but it hasn’t.
In our case, I think we found that the heavier cable failed more quickly. We went from the original Baron cable which was around 1/32 to stainless aircraft cable about 1/16 in diameter - and it failed much more frequently. Bent through a given angle, the differential stress on the outer wrap is twice as much, roughly. Maybe it would go longer between outright failures, but it frayed much more frequently.
Brett
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In our case, I think we found that the heavier cable failed more quickly. We went from the original Baron cable which was around 1/32 to stainless aircraft cable about 1/16 in diameter - and it failed much more frequently. Bent through a given angle, the differential stress on the outer wrap is twice as much, roughly. Maybe it would go longer between outright failures, but it frayed much more frequently.
Brett
Thats is very interesting.
I have no idea what kind of cable I have. It's rugged and ugly. I will show it to you at the nats and see what you think.
It should have frayed years and years ago but it hasn't.... I am sure it will now though since I opened my mouth.
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Sorry to see that happen Chris!
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So the handle had 293 flights on it total? That's pretty alarming.
I hate to see the plane crunched, it looked like a great one.
Yes that handle was purchased for that airplane. The crazy part is that I pull tested the plane 5 flights before at the Polk City contest and then flew the day before in 15 mph winds and it wasn't an issue. The first flight the next day in dead air it broke. I even changed the lines that flight so I looked at the handles cable to see if it was fraying... since that green cover is on it and the cover wasn't warn I assumed it would be fine... guess not. I have another Kaz handle that has over 1000 flight from me on it and it was given to me by Robby Gruber so I assume it had a couple hundred flights from him...
When the plane crashed I thought for sure the new lines were the issue but when I looked it was obviously the cable... sad day. Going to a hard point handle from now on.
-Chris
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I sure was looking forward to seeing you fly the Typhoon at the nats. Hang in there Bill
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Very similar cable is sold as deep-sea fishing leader, and it's about as reliable as any other. It might actually last longer than the 1/16 bare aircraft cable we used to use. I have seen a few cases where there was a clear soft spot it you tried to flex it indicating that most of the strands were broken, but you can't see the strands all loose like you can with bare cable.
Unfortunately there doesn't seem to be any real cure for the problem. If you use a cable handle, you just have to inspect it before *every single flying session* and carry the necessary repair bits with you in your tool box.
Brett
Exactly the problem, Brett! The plastic sheath hides the failure as first one strand breaks and then another. Yes, I am sure the cable is as reliable as any other, but when you can't identify the gradual failure, you WILL get a catastrophic failure.
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Exactly the problem, Brett! The plastic sheath hides the failure as first one strand breaks and then another. Yes, I am sure the cable is as reliable as any other, but when you can't identify the gradual failure, you WILL get a catastrophic failure.
Yeah, you're absolutely right Bill. However the real problem is the stupid cable. The solution is to eliminate the cable and use a hard point handle.
Really sorry to see a beautiful airplane like this lost to a stupid cable! Keep flexing a cable around a sharp radius and it will fail!
Randy Cuberly
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Yes that handle was purchased for that airplane. The crazy part is that I pull tested the plane 5 flights before at the Polk City contest and then flew the day before in 15 mph winds and it wasn't an issue. The first flight the next day in dead air it broke. I even changed the lines that flight so I looked at the handles cable to see if it was fraying... since that green cover is on it and the cover wasn't warn I assumed it would be fine... guess not. I have another Kaz handle that has over 1000 flight from me on it and it was given to me by Robby Gruber so I assume it had a couple hundred flights from him...
When the plane crashed I thought for sure the new lines were the issue but when I looked it was obviously the cable... sad day. Going to a hard point handle from now on.
-Chris
2001 Nat's I had a lead out break at the belcrank. Post-Mortum revealed a burr on the brass bushing that sawed through the cable over time. It was pull-tested successfully minutes before the flight.
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Man, that's a big time bummer Chris, sorry to hear it. I hope you can get your replacement in the air real soon.
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Hi Chris,
Sorry about your tough luck.
I've just about given up getting my new ship ready for the NATs in time.....which is in the primer. So, if you have a chance at getting your backup plane ready from the primer stage, then by gum, I should be able to, also.
I use a similar handle with the green coated cable. I think it is the same cable Windy used, and I've replaced the cable about three times in ten years. Checking just now, I see two breaks in the green coating, no fraying in the actual cable.
I'm wondering if somehow during manufacture a weak spot on the cable was coated? Whatever the cause, thanks for showing it, lots of us can take appropriate action to preclude such an event in the future.
dale g
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I had a cable fail in the handle on my '82 Nats's plane (to be). It left lots of little balsa pieces on the parking lot I was flying on.
From then on I only used hard point handles of one form or another. They have morphed into my current design that weighs around 18 grams. I noted that you are already going to a hard point handle. Good move, even for a 63 flight mortal!