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Building Tips and technical articles. => 1/2 A building. => Topic started by: david beazley on September 03, 2012, 02:57:05 PM
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Today I was in the process of re-hab-ing a 1/2a combat wing of unknown vintage. My buddy got 2 of them with Cox engines, a tool box with engine parts and various CL items for $20 at an RC swap meet. He gave me one so we could play. Mine had mono filament lead outs (!) one of which was busted. I cut into the sheeting to get to the bell crank and decided to use some 20# Spectra as lead outs. After learning how to tie a double five turn knot and got the lengths close I started to recover the wing. I figured this was going to be a beater so I had some fluorescent green Monokote and started to cover it. All was proceeding swimmingly I was using my Monokote heat gun to tighten the covering on the tips when I heard something hit the floor. I looked down and there were both lead outs laying on the floor! The heat from the gun was not enough to burn thru the Monokote BUTit was enough to burn thru the Spectra!!!
I just tried again to replicate it and sure enough, the Spectra will burn thru before the Monokote will!
Be advised!
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That is great information and requires some careful testing!
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Can anyone provide a link to a suitable Spectra line for say a Baby Flite streak with a Black Widow? Are there any brands to avoid?
I have a spool of Spiderwire EZ Braid 15lb - which I believe is a Dyneema product. Is this suitable?
I have been practicing palomar knots.
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For my own personal satisfaction, I wouldn't run this type of line to a bellcrank that is installed internally. Providing stainless leadouts just like any other model would be more practical. You can't inspect the line terminations. Most if not all of my planes have exposed bellcranks. I always leave a small tag after the knot which I inspect prior to flying. I've used all of Phil Cartier's advice on using this type of line. Phil has been using these lines in speed limit combat, 1/2A combat, and as posted in the combat section here, fast combat at the Nats. Phil's experience has been over several years and has allowed the use of this type of line for combat use even by the AMA. My son and I use Spiderwire for 1/2A combat using Norvel's. I use 30 lb. 8 lb diameter Spiderwire. I'm sure this is overkill for the models I'm flying. http://www.gandermountain.com/modperl/product/details.cgi?pdesc=SpiderWire-Stealth-Braid-Fishing-Line-Moss-Green&i=441597&r=view&aID=504AE11A&cvsfa=2586&cvsfe=2&cvsfhu=343431353937&s_kwcid=goobasecontent_goobasecontent_filler&cID=GSHOP_441597 The problem with Spiderwire is the color choices. Although it's availble in yellow, it typically has to be ordered. The majority of stores carry moss green. This stuff is impossible to see in the grass. In addition, this also happens with Dacron, these lines over time will absorb oil. I've been successful in removing it with a alcohol soaked rag and wiping them prior to flying. This may be more noticeable with the models I'm flying as they're typically under 5 oz's. When I see speed and performance falling off, I look at the lines. I generally cut a new set. Anytime I use these lines, I use nylon bushings where it penetrates through. I see extensive chaffing in this area and I replace when needed. In the event a model has typical copper eyelets for wing tip leadout guides I would strongly suggest not using them with these lines. A piece of Sullivan Nyrod would be a better choice with the ends chamfered. Ken
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I have been using 10lb yellow Spectra lines on my 1/2a sport planes up to 42'. So far no issues but I have noticed it is sun fading fast. I use a single line through the handle with connectors tied on the line with a palomar knot.
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I use Power Pro 10lb yellow for 1/2A's It is available all over the place, I think I got mine at Bass pro Shops http://www.basspro.com/PowerPro-Braided-Spectra-Fiber-Micro-Filament-Line-100150-Yards/product/44282/
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Thats it!
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rick,
I use the same kind of handle, I have trouble getting two separate lines the same length.
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In addition, knots are the weak point and eliminating half of them is a good thing!
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this is true.
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Can you pinch Spectra line under a smooth wooden block with radiused edges to lock it down?
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The trick is to thoroughly wet the knot before cinching the it tight. You need the lubrication to get solid seating without abrasion. I suspect KY jelly would do the job even better, then could be washed out. ;D
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I think Spectra just needs a little learning time. The first few times I used it the pull tests failed, but once you learn the technique and the knots, it is OK. Larry is right about wetting, ask any fisherman.
That said I don't use it on anything larger than a 1/2A
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Single line through the handle and leave enough of a tag at the knots so that you can notice any slipage when inspecting. That's worked well for me.