I do hope you are talking in terms of center of plane to center of handle.   The max is 70 feet CoP/CoH.   Most of my planes I fly on 60 foot lines, as they are in the 35 or 40 size plane.  The planes with 46 size OS is flown on 65 foot lines.  It all depends on the lines size diameter also as most of mine are .015.  I have used .018 because of high wind conditions several times.  But, in reality it depends on the feel of the plane to you the pilot.  I probably fly faster than most people because it feels good to  me.   If you go for lap times mine are usually in the 4.9 to 5.1 bracket.   

That's all good information. Exactly what I was trying to figure out. Maybe there's a book out there with these tidbits but I haven't come across it yet. My son and I are flying in our first competition next weekend, I always find hanging out with the pros helps us improve. 

One thing to remember, Tom, is that the maximum line length allowable is measured from the C/L of the handle to the C/L of the model.  So the " 70' " maximum is about 67' of lines measured from eyelet to eyelet for a large stunter.

Bill

Unless you FAI then it's 21.5 meters. Or about 70 feet 6.45" Center to Center.

Just a newbie question, at what point in size or speed do you generally make the jump from 60 to 70 foot lines? Or is it more complicated than that? Having flown nothing bigger than a 40 and about 55 inches of wingspan, I was curious.

    10 feet is FAR too big a change to make just to adjust the speed. A foot is a pretty significant change.

    For reference, most current competitive 40-75 sized models are somewhere in the range of 63-65 (67 or so being the limit as mentioned above, since I am talking eyelet-to-eyelet measurement). As far as where to start goes, for a typical 650 square inch piped airplane I would suggest 64 and then adjust from there - in maybe 1 foot increments. I used to carry them in 6" increments, but now I just have my usual lines (64') and a backup set, and then a 63 and 65 each.

    For a 20/25FP or LA airplane, in the range of 400-500 square inches, I would suggest starting around 60-62. For a  Fox 35/McCoy35, maybe 56-58', and carry some 54 and 55s to test with.

    Brett