Just returned home from a wonderful trip to Colorado Springs, CO. It
truly is IndoorTown, USA.
The glider flown Sunday is a rough prototype for a Kent glider.
Flapped, 25" span and around 75 squares. Left-left pattern. 9.5g
before repairs...
I have a feeling that this whole indoor DLG thing can be done in more
ways than one. I used incidence change, a fair amount of opposite tip
weight, and high spiral stability to get the model to transition. It
doesn't have the usual "pop" transition of a flapped low ceiling HLG.
The launch is really effortless but will require practice to pin down
timing. Using an underhand softball-ish flick, the glider launches at
a 35-45 degree angle wrt horizontal and bunts into a long cruise for
the first half turn. The model is still not down to glide speed as it
is coming back your way. I was launching across the full length of the
auditorium.
The tail boom is really the coolest part of this airplane. Seven thou
unicarbon on each side, epoxy, and blue Dow HighLoad 60psi foam core.
Kevlar tow wrap gives burst protection and a little bit of torsional
stiffness (don't need much). The compression side (nearest the
throwing tip) has a split .020 rod glued full length as a weblet.
Failure mode testing of sample material without the weblet showed
compression failure of the foam and simultaneous inward buckling of
the carbon. Simply adding a weblet quadrupled the ultimate strength.
Epoxy is heavy, so don't use much, right? I cut a tapered peice of
foam, "sponged" on epoxy with a paper towel, and laid up the carbon.
Cover in saran wrap and then 1/4" foam rubber. Place the whole shebang
between two solid surfaces and stack up as much weight as you have. I
have a bar vise that's long enough to do the job, so I don't use
weights The foam applies even(ish) pressure to the layup. The
resulting structure is very stiff and reasonably strong.
Chris
Received on Wed Jan 31 2007 - 00:25:12 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET