Watch the video:
slope_stik.avi (3 mb AVI file)
Taken from the SPAD forum (see:
http://spadworld.net/viewtopic.php?p=45394)
So I've been working for the past few
days on creating a SPAD sloper that can fly in light air. Here in Santa Barbara,
CA where I fly, we've got a number of very beautiful sites but due to our
coastal orientation (east/west as opposed to north/south) and the direction of
our prevailing winds (NW), we generally get pretty light slope lift, on the
order of probably 8-10mph average. So we have a need for gliders that perform
well in light lift and are fun to fly "low and slow".
Till recently I hadn't had much luck finding a SPAD design that would work well
in light lift. The Mugi (aka Flik) is a nice plane, easy to build and cool to
look at, but it really does require a moderately strong wind to fly well (at
least 12mph+ in my personal experience). The other sloper designs I've seen all
look like they have nice performance, but come from places like the UK or
Washington State where there's no shortage of strong wind and powerful lift.
So this past week I decided to try something a little different out. I wanted to
design something that would be: A) easy and fast to build using SPAD techniques,
B) able to fly in light lift (target 8mph or less), and C) fun!
I think I may be on to something with the result!
The above flying picture and movie were
taken on a rare day when the wind was 17-20mph. The plane flew pretty well all
things considered, but it did have some trouble penetrating due to the single
surface airfoil and obviously all the drag from the gear being exposed.
However, I've flown Prototype #1 and Prototype #2 in light wind and they
performed well. I haven't had a real good day to test them further yet, but will
report back with the progress.
Prototype #1 has an AUW of 4.4oz. and a slightly smaller wing that Prototype #2,
which has a slightly bigger wing and weighs 4oz. even. Obviuosly for these
planes the lighter the weight and the bigger the wing, the better they're going
to perform in light lift. I'm still trying to work out the "ideal" dimensions
for the plane but I know what I've got so far works well. Here they are:
Wing:
24" wingspan
6" chord
~1/4" camber kink
Airfoil kink at 30% MAC, or 1.8" back from leading edge
Ailerons 25% MAC, or 1.5" up from trailing edge
Horizontal Stab:
7" span
3" chord
Elevator 50% of MAC, or 1.5" up from trailing edge
Stick-Fuse:
1/8" x 3/8" Basswood, ~24" long (cut to suit)
Radio Gear (submicro gear required to get lightest weight):
Cirrus MRX-4 single conversion receiver or similar size/weight Rx (Electron 6
with case removed would be a good dual conversion option, though a bit heavier)
Cirrus CS-5.4 servos (x 2)
150mAh NiMH pack
I'm calling it the Micro Slope Stik, or maybe "MiSS" for short. Though I'm happy
to hear alternate suggestions. It's a small conventional glider built from 2mm
Coroplast that uses two channels (aileron and elevator), has a single-surface
(kinked) airfoil, and builds in an honest two hours or less.
