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Building techniques / Re: Another Nobler ARF Build
« Last post by Colin McRae on July 03, 2025, 04:44:06 PM »Let me pass on what I did on my arf. After replacing the bellcrank I removed the top ribs on the inboard tip. I don't know what you will use so I will leave that to you. I made mine so that the leadouts were above the C/L like they are on the ARF. Before adding the adjustable box, find a 30+" arrow shaft and cover it with sandpaper. Thread the forward leadout through the covered shaft and slowly grind the ribs away until you can get the forward leadout to the furthest aft position the leadouts could be with it pulled as far as it will go. Biggest mistake in converting is to not allow for the leadouts to move without hitting something. Make sure the aft is not hitting any ribs when the adjustable is full forward. I think your BC is mounted behind the spar enough that this will not be a problem and the 4" will give you maby 2 ribe you don't have to sand. You will have cut the center out of about 1/2 of the inboard spay, maybe more. When you have it all cleared out get some stiff 1/16 x 1/8 and glue them vertically just behind where the back leadout passes through the rib with it in the full aft position. That will replace a small amount to the crush strength from cutting the spar.
Good Luck - Ken
Thanks, Ken, for the means and methods as they will surely help. And I have removed the 3 upper wing tip ribs as you have done. I will reshape the wing tip airfoil once I have the wing tip slot installed.
But I was sort of inquiring the distance behind the CG to set the 'centerline' of the lead outs as a good zero point. Based on good flight performance, where have others set their lead out position on their Nobler ARFs?
So where is a good lead out position for a good flying Nobler ARF? The stock ARF has rudder offset and the C/L of the fixed lead outs is close to 2" behind the CG. I will be removing the rudder offset, and 2" seems way too far back.
Thanks
Colin