How to make reed valves out of a floppy disk

If you save old airplane-kit "boxes" (as I do...) there may be some mylar "hinge" mat'l. in there that's leftover or even "unused" that may work. "Sterling" furnished this hinge mat'l. with their later kits. "Acetate" canopy mat'l. might also work; depending on the thickness.[/quote]
Coincidentally, the mylar disk material is computer floppies does make excellent (very light, very strong) hinge material for moving flying surfaces.

Michael
Newmarket, Ontario[/quote]
Hi Michael, What do you use for glue with this method?[/quote]

hi Roddie,

I made my comment about the mylar material from old computer floppies making excellent hinge  material based on a discussion in an r/cgroups.com forum (most likely in the 1/2a subcategory), not on personal experience.

Since relaying that experience of others, I did a small test as follows:
- salvaged mylar material from an old 3.5" floppy,
- removed the recording finish with lacquer and scrubbing; thickness is 0.08 mm (the thickness of the small mylar tab that is under the white anti-friction disk, btw, is 0.14mm and subjectively much stiffer than the round mylar disk
- gouged out hinge slots in balsa using a #11 xacto knife, not widening anymore than necessary to slide in the mylar without obvious binding
- injected a bit of standard big box yellow carpenter glue and white Wellbond  into alternate slots with a syringe as well as smearing a bit of glue onto both sides of hinge material
- on four test pieces of hinge material, the above two types of glue and on one of the two samples of each glue type, perforated the hinge material with 6 or so T-pin holes ... and inserted the four hinges into their slots to a depth about 3/8"+
- after 24 hours tried to pull out hinges by as vigorous action as I could with a thumb and forefinger grip... none of the hinges moved

-the hinge material is very flexible... while I wouldn't expect an elevator on a 1/2a size plane to droop of its own weight with these hinges I wouldn't be surprised if a solid balsa elevator would droop on .40-.60 size plane

Despite this good news, I expect it would be quite 'fussy' to insert a moving control surface with several of these hinges into its fixed flying surface (eg. rudder fin) without having to widen the hinge slot significantly and then having to peg anchor the hinges in the fixed control surface.

I'm just returning to r/c after a break of 20 years... on the several 1/2a size planes that I still have from that period I used a relatively thick 3M clear tape as a full length control surface hinge, using the adhesive on the one size of the tape against the fixed and moving surface.... those hinge today still hold well, have not yellowed, etc.

I also like on light weight plane structures and gliders stitched hinges using lightweight clear fishing line.

cheers

Michael
Newmarket, Ontario