ORIGINAL: ameyam
Dear All,
This is a bit silly, but I can search for it and install it only if I know what it is called: I just received a US40+ kit a close friend built for me. However, he built it such that the nylon bolts that hold the wing to the fuse screw direct into some wood instead of putting in a nylon bolt nut (See picture). In many of my ARFs, the same arrangement has either a SCHS nut in the fuse side or a nylon nut there. I am worried that after assembling and dis-assembling the plane a few times, the screw will shear straight out of the wood and I will have a crash. So please tell me what the nylon nut is called
Ameyam
Looking at your post, yes indeed, what you want is called a 'blind nut'. Is is metal, and the most common size in the States is 1/4 - 20.
As has already been noted though, those wood threads can be just as strong if hardened with CA. This system has been used for wing attachment for decades. Very simple, very reliable.
Please note, avoid getting CA on those wing bolts. It makes the nylon brittle, and subject to cracking.