Aki, Bob, Fred,
thanks for the info and tips. Looks like my big mistake was to use
unthinned glue - I somewhat had the mental image that a thinned glue would
not dry fast enough, and thus would not come off the mandrel. Turned out
to be just the opposite, with thinned glue they come off more easily!
I added a pic of my first F1D hub to the photos section, under "VP's
only".
http://ph.groups.yahoo.com/group/Indoor_Construction/photos/view/ffe6?b=15&m=f&o=0
This uses similar construction than the F1M hub, but smaller
diameter poltruded carbon tube. also the way of attaching the blade
hangers is different. In F1M, I had a groove in the main tube for the
hanger wire to go in, but this turned impossible to do on the thinner
tube. Thus the main prop hanger is 1.0/0.5mm tube sanded in half, and prop
hangers are 8mm lengths of 0.7/0.3mm tube glued onto the "slot" of the
larger tube in half. The centre of the hub has the whole tube intact, so
there is room to drill a 0.7mm hole for a piece of 0.7/0.3 tube to take
the shaft.
The prop hangers are 2mm paper tubes. Did not weight them separately, but
together with the 8mm of carbon tubes and the pieces of piano ware as
hinges, one unit weights 20mg, so I guess my paper tube weight is
acceptable now.
The whole hub weights 136mg. A bit too much, but a decent starting point,
especially as the carbon construction is solid. There is room to file off
a bit more, and also make the wrappings (glued with cyano to ensure good
grip to the carbon) tidier and thus lighter.
-Tapio-
Received on Mon Jan 28 2008 - 23:46:56 CET