One of our fellows asked me a week or so ago if the non metallic lines that are used in combat are legal for any of the C/L racing events. I had no answer so thought I should ask here. Official answers??   Thanks

Thanks. I'll pass it along.

Won't know until someone tries them.   I don't think I would try them in competition, but if I had a fenced in area I would do some experimenting. 

Experience in combat has been great - I will not be going back to SS unless required.  Lines last longer and plane flies much better with them.  Esp tru in combat as they fly out of line tangles much much much better than any steel lines.  No curly que lines, no kinks, easy to tie knots (but be sure to tie the right ones!).  Buy lines from cabelas at 1/2 the cost of steel.  Lines are bright yellow so you can see them in the grass.

Not sure they are needed in racing.  Could consider them in clown if we move to 60' as they are much lighter than steel and might help these small planes on long lines.  Needs testing.  Maybe solves a problem that does not exist in the first place.

Material identification can be an issue but that is a problem with all lines, not just GSUMP.  Other than speed events, we dont have a line material spec for any events.  Problems may arise when a reliable source or brand changes their formula in some way that affects us.

Measuring line diameter can be done, its not as easy, but it can be done repeatably.  Measure with a light touch.  Crushing the line makes it harder to measure but does not affect the strength of the lines.

An effective pull test provides a backup, just like our existing lines.

In my opinion, the added performance and safety of these lines greatly outweighs these potential issues.

One factor that seems to be overlooked in the use of Spectra lines is their electrical conductivity, or lack thereof. Being non-metallic, wouldn't they have a margin of safety over metallic lines when it comes to high-tension power lines, etc?
dg

I wouldn't depend on ANY line material to make flying near power lines safer.

Good point on specifying the material - I haven't seen an industry standard such as ANSI related to these materials so we are relying on our pull tests a bit more.   BUT, data from the combat field shows fewer flyaways with GSUMP than with steel and I would not agree with your assessment on trouble or liability.  Measuring lines is not an issue either.

For combat, I have no doubts about the improved safety with GSUMP due to greatly improved performance during line tangles.  For other events, including racing, the safety improvements are limited to eliminating kinks and curly-cue lines.

I was going to say something about flying close to high tension lines.  But, then I remember Billy Melton talking about his flying low at the NATS  in carrier.  He told me that in the summer time in Las Cruses NM he would get static shock if he flew very high in the circle.   At Pawnee Rock KS we were getting static electric shocks one year.   All CL flying stopped that day.  Don't know if the new plastic/composite lines would have helped or not.

Ask Sparky what happened when his combat model and stainless lines got into the high voltage cables during the Nats in Lincoln.  Combat events now require a wrist restraint as well as a shutoff should the lines be cut.
A catastrophic failure in Racing (both lines break) is much more serious than in Combat where (hopefully) the shutoff works properly.  Unless you're an idiot flying near high tension lines the danger isn't to the pilot but to spectators and pit crew or expensive transformers in the case of the Lincoln Airport situation.  The price of a 900 meter spool of 100 pound test line on eBay is about the same price as a single set of stainless flying lines
in a hobby shop or half the price of bulk line.  They can be tied to an exact length, they'll pull test to near 100 pounds even with the simple knot suggested on the Combat Forum.  The lines will eventually fray at the leadout guide but that shouldn't be a problem with racing models since there isn't the movement compared to a constantly maneuvering combat model.  So far there have been no catastrophic failures with combat models.  I'm really more
concerned with a fatigued pilot trying to hold onto a GO 25 powered Slow Rat for 140 laps.