Composite-ARF YAK 55SP
(3m span)
4
Leave the transmitter antenna retracted, and check the distance you can walk before ‘fail-safe’
occurs. Then start up the engine, run it at about half throttle and repeat this range check with the
engine running. Make sure that there is no range reduction before ‘fail-safe’ occurs. Only then
make the 1st flight. If you feel that the range with engine running is less then with the engine off,
please contact the radio supplier and the engine manufacturer and DON’T FLY at that time.
Check for vibrations through the whole throttle range. The engine should run smoothly with no
unusual vibration. If you think that there are any excessive vibrations at any engine rpm’s, DON’T
FLY at this time and check your engine, spinner and propeller for proper balancing. The light-
weight sandwich composite parts don’t like too much vibration and they can suffer damage. The
low mass of all the parts results in a low physical inertia, so that any excess vibrations can affect
the servos and linkages.
Make sure that your main and stab tubes are not damaged. Check that the front and rear anti-
rotation pins for the wings and horizontal stabiliser are located correctly in their holes, and are
not loose. Check that the 4 plastic wing retaining nuts are tight, that the M3 bolts retaining the
horizontal stablisers on to the aluminium tube are installed and tight, and that the hinge tubes for
the rudder and elevators cannot come out.
If you carefully checked all the points above and followed our advice exactly, you will have a safe
and successful first flight - and many hours of pleasure with your Composite-ARF Yak.
General information about
fully-composite aircraft structure and design
All the parts are produced in negative molds, manufactured using vacuum-bagged sandwich
construction technology. All parts are painted in the moulds, either single colour or designer
colour schemes. A revolutionary production method, called TAVS (Total Area Vacuum Sandwich),
enables us to present this aircraft with incredible built-in strength, while still being lightweight,
and for a price that nobody could even consider some years ago. This production process has
huge advantages, but a few disadvantages as well. These facts need to be explained in advance
for your better understanding.
Description of Parts
The Wings:
Both wing halves are made in negative moulds, fully vacuum-bagged, using only 2 layers of cloth
in combination with a hard 2mm foam sandwich to form a hard and durable outer skin. Because
of this TAVS technology no additional structural parts are needed except for the main spar tube.
The ailerons are already hinged for you. They are laminated in the wing mould and are attached
to the main wing with a special nylon hinge-cloth, sandwiched between the outer skin and the
foam. This nylon hinge is 100% safe and durable. You never have to worry about breaking it, or
wearing it out. There is no gap at all on the top wing surface, and there is a very narrow slot in
the bottom surface, where the aileron slides under the main wing skin during down throw. This
hinge setup is the cleanest you can ever obtain, but you have to take some care during assem-
bly for proper installation and servo set up.
First, the hinge line is on the top surface of the wing, not in the centre. This is NOT a disadvan-
