Looking at various vendor product lists, I noted lines are available at 60 & 70 ft. lengths.

Many years ago I used to fly .15-.21 size models and IIRC lines had to be around 50 ft. (?) long.

Is that correct? and if so, where do I get this length of ready for use lines?

Thanks!

OK, found Brodak has the lines I was looking for.

Erez,
It would be worthwhile to check that the lines ARE the length you want. Years back, several manufacturers offered lines by the diameter and length they marked on the packaging. Not all were the specified length; many were several feet longer. For a smaller CL model, the difference between, say 52.5' and 60' feet or more can make a difference! Brodak has a fine reputation for quality so this should not be an issue, but I'd still check to assure confidence. (Sorry, if you think in meters, you'll need to convert...)

Out of some interest in closing the loop on the OP's question, would a pilot want to be thinking .012 at 60 feet for a stunt airplane and modern schneurle .15?
I was just flying a Ringmaster Jr. with a TD .09 on 50', .012's. It felt a little light on wingovers. I am building an RM Jr. for a .15 TD.

BG,
I don't think of a Medallion or TD Cox .15 as a "modern" engine, although they were definitely above the level of most USA made .15s when they appeared.

52.5' by .012" WAS a basic starting point for .15 CL models, and still serves well. It can be "survived" if too small, as well, as - to be hoped - too soft on initial flights.

We MUST have in mind the usefulness of changing both line length and diameter until the RIGHT fit for the model is found. Once there, all is good and remains good.

Cox .15 Tee Dee is still a reasonably powerful engine, and IMO up there with the plain bearing sport Schneurles. I found that to be true with the older cross scavenged Enya .15-III TV. I replaced the OS .15FP-S and 8x4 prop with the Enya and 8x6 prop on my Ringmaster Junior, (bolt pattern is close enough), was getting the same lap speeds running a wet-2. This is at our 4,300 ft. elevation. Downside was weight of engines, a little hefty for the smaller Ring even without mufflers.

Regarding Ring Jr. with .09 Tee Dee being light in wingover, may be going to 42 ft. lines? GCB was using that length on his Ring Jr. with Enya .09 engine. Tee Dee is a tad more powerful, may be experimenting with repropping might provide better thrust on 50 ft. lines?

Thats an obscure engine size, no wonder youre having trouble finding info. You might have to make your own. I would never use ready to use lines myself. Just get some 60 foot lines, cut them to the length you want and wrap them properly with copper wire, eyelets and heat shrink tubing.

Been wanting to go with Spectra lines. Thought I'd save some money, bought some inexpensive stuff from an E-Bay vendor in China, big mistake. I've ordered stuff from China before with good success, except this and one other exception. Was labelled as Spectra but was not. For this next time will go to a US fishing supply store for the genuine article. Supposed to be 70 lb. test, lines were very stretchy, struggled to control my Ringmaster, hair raising flight with no down control in a very tight loop above, 2.5 second laps on a full tank. True Spectra AFAIK has little give.

Live and learn, had decent luck with Sullivan synthetic lines before, and of course steel cables have always been reliable.

Cant imagine anyone showing up at the world championships with fishing line. Its all good till your lines snap and you kill someone and ama wont cover you because you chose to ignore the rules on the type of lines you should have been using to begin with.

You need to catch up -- Spectra lines are legal in combat and specifically covered by the AMA safety code. Yes, we have had issues with cheap Chinese knock-off, but known brands of fishing line that are Spectra or Dyneema are well-tested.

Ok great, and ya its been a few years since i flew.

Speaking of line length here;s a funny video some RC guys made trying to fly an electric CL plane. The last part of the video they get it flying again but it falls apart in mid air. I was surprized to even see this on such a popular RC channel. https://www.youtube.com/watch?v=HlRx-G-4X9s