Multiplex Alpina 4001
The Alpina from Multiplex has been in Multiplex's lineup since
the seventies, and has gone through different stages of development.
It started out as a 4m sailplane with ailerons, rudder elevator, and optional
spoilers, with a Ritz 2 airfoil, which made it a pretty good thermal sailplane,
but not
terribly aerobatic.
The latest version is the 4001, with flaps, and a modified RG-15 airfoil. It
will still perform reasonably well in thermal flight, although it is no floater,
but with the
RG-15 airfoil, it is a much more dynamic airplane, capable of doing almost any
aerobatic maneuver in the hands of a good pilot ( I'm not one of those... )
Before I moved to Cincinnati, Ohio, I lived in Caracas, Venezuela, where all my
flying was on the slope, with one of the original Alpinas.
So, when I came here to slopeless Ohio, I had to learn flatland thermal flying.
After having flown and eventually crashed my Alpina 4001 on the winch, I decided
to try electric assist, and converted the Alpina to electric power. I equipped
it
with a Kontronik drive set 502, which consists of a FUN 500-27 brushless motor,
mated to a 5.2:1 gearbox.. It was powered by 14 cells and drove a 14x8.5
prop.
Although this combination worked, it was kind of marginal, especially on launch,
so I changed it to a Kontronik drive set 1001, which is a FUN 600-18
brushless motor with a 4.2 :1 gearbox. I kept using the same 14 cells, but now
it was driving a 17x11 prop, and this combination worked much better.
The 502 drive got a new job, powering my
CHK Cumulus e
sailplane.
Before I converted the Alpina to e-power, I had
crashed it on the winch, which was one of the reasons which made get into
electrics.
Since then, I had been flying it with the wings of my Multiplex ASH26, which are
identical.
Now, with the ASH sold, the Alpina is "wingless".
During this fall/winter I will build a new set of wings for it. Span will be a
little more, 4.3 m ( 170 in ), airfoil will be a HQ 2.5/11, and the wing will be
4 piece,
with flaps and inbd& outbd ailerons.
e
After having posted the question
about what airfoil and planform to use on one of the german discussion boards,
RC-Network,
Hans Rupp ( screen name "haru" ) ,one of the users there, was nice enough to
help me out, and
came up with this.
Just recently, I ordered the cores made from pink foam at Bob Gellen's company,
Flyingfoam.
Progress of the work will be documented here.