The large flaps are effective, allowing the Blanik to land at fields
that aren’t designed for long, shallow approaches.
the model when it’s broken down for transport. This means the
airplane can sit on its wheels, whereas many models with the
main gear on the wing require a cradle because the nose gear
remains on the fuselage and the main landing gear are removed.
Even without the wingtips installed, the airplane takes a lot
of space. This might be a problem for smaller vehicles.
Field assembly is easy. The aileron servos and wingtip lights
plug in, then the wingtip slides into place over the carbon-fiber wing tubes. It is secured by a hex-head screw. Two
thumb screws secure the hatch, and when the battery is in
place, you’re ready to go.
The power loading works out to roughly 145 watts per
pound. This should be plenty of zip for sport flying and light
I wanted to be thoroughly familiar with the flying
characteristics of the Robin S before trying any towing with
it so my flying buddy, Adam Strong, and I headed to the field
with several charged battery packs. The plan was to give Adam
several flights as well because he would be piloting the Robin
S during our aerotowing flights.
Taxiing on both a paved and a grass runway was easy. The
main landing gear’s wide track offers stability on the ground. A
few minor radio adjustments to the nose wheel servo had the
Robin S tracking nice and straight.
Slowly adding power, the Robin S accelerated nicely and
was airborne in 100 feet. Two clicks of up-elevator trim had it
flying hands off! Up high and into the wind, I performed a stall
test by reducing the power to idle and adding elevator to try to
keep it level.
I found that the forgiving stall characteristics of the full-scale aircraft were passed down to the model. Even without
using the flaps, when the Robin S stalls, it simply drops the
nose slightly and although the sink rate increases, the airplane
doesn’t show any tendency to drop a wing or snap. Relax the
elevator and it resumes flying as though nothing happened.
In normal flight, you need to add a little rudder in turns or
the Robin S will drag its tail. Some aileron differential helped,
but to make good-looking turns, you need to add some
The Robin S is designed to be an extremely stable airplane
when upright, but it also holds its own in inverted flight. The
wing design requires some down-elevator, but I was surprised
at how easy it was to fly inverted. The roll rate is plenty for a
sport model and both the rudder and elevator are effective.
Knife-edge flight needs some correction for roll coupling
and some up-elevator, but with some speed it will fly a knife-edge pass the length of the runway without feeling as though
it’s going to snap out.
Forced into a spin, the Robin S will stop almost as soon as
you release the sticks. With 25% exponential, it has a good
balance of responsiveness without being twitchy. All of our
flying was done at high rate.
My first real surprise came when I dropped the flaps to
land and the Robin S didn’t balloon at all, so no elevator
compensation was required. The model locked into a nice
approach at 1/3 power with full flaps.
Airplanes with tricycle gear normally roll on the mains a
little way before settling on the nose wheel. In the 10 flights
we made that day and on all of the subsequent towing
flights, as soon as the main gear touched down the Robin S
immediately rotated so the nose gear was down. It was not a
problem, but it was not something I’ve seen before.
The Robin S flew equally well on a 5S battery pack as it
did on 6S power, with no visible drop-off in performance. I
wouldn’t tow gliders on 5S power, but otherwise the difference
On the second day out, it was time to try some glider
towing. With the towline set on both ends and a control check
completed on both airplanes, Adam advanced the power on
the Robin S and off we went. The Robin S towed the nearly
12-pound Blanik aloft with a nice, scalelike climb. Three full-power tows to approximately 800 feet are possible on one
5,200 mAh 6S pack.
The Robin S is generally stable during a tow, but the
upturned wingtips can subject the model to problems if you
have much crosswind ( 8 mph or more), so try to minimize
your time spent in a crosswind. If there are obstructions such
as trees or fences on the approach path at your field, be sure to
keep the towline clear when you land. If you use a birdie as we
do, the towline will remain nearly straight.
Flying the Blanik
Transportation and field assembly are easy. SebArt RC
provides a bag to protect the large wings. The wings slide onto
the substantial wing tube, the Taildragger RC harnesses are
plugged in, and the wings slide into place.
I replaced the provided wing retention hex nuts with wing
nuts to make them easy to install by hand (the ears on the rear
wing nuts need trimmed). The cockpit is easy to remove, so
the switch was installed in the radio tray for a clean exterior.
I’ve done plenty of glider towing, so I have a feel for what
will work versus what might work, and I have learned an
expensive lesson about what won’t work. I admit that I felt that
the combination of the finished weight of the Blanik, a 6S tow
airplane, and the physical confines of my home field that the
Robin S/Blanik combination fell into the “might-work” category.
Knowing what to expect from the Robin S, but unsure of what
to expect from the Blanik, I elected for safety’s sake to go with a
larger and more powerful tug for the initial flights.
71 Model Aviation SEP TEMBER 2015 www.ModelAviation.com