Extreme Flight YAK-54 ARF, Instruction Manual

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Set-up and trimming
Besides basic assembly, this is the most important part of preparing your
airplane for flight. It can also be the most time consuming, but once your
plane is properly dialed in you will agree it was time well spent.
A common phone call I get goes like this: “I can’t get my plane to fly right.
It doesn’t fly anything like your plane in the video. Something must be
wrong with mine”. I am always surprised to learn that the customer usually
has not varied his CG, control throws, or anything else since first setting up
his plane. Getting your airplane dialed in is a continuing process that may
take many flights to achieve. Take the time to do this and you will be
rewarded with a great flying aircraft.
The
center of gravity range for the 50cc Yak begins at 6 3/4” from the
leading edge of the wing measured at the root (center of the wing tube) and
extends back ¾” from this point. Make your first flights at the front of the
CG range. There is no need to have the Yak excessively tail heavy to
perform 3D maneuvers. At this time you will also want to balance your
plane laterally. Add a small amount of weight to the wingtip to achieve
proper lateral balance.
As mentioned earlier, if you are planning to use a tuned exhaust system you
will need to mount all batteries as far forward as possible. The tuned pipe
adds several ounces behind the CG and great care must be taken to counter
this without adding additional weight (or as little as possible).
Control surface throws
I highly recommend that you purchase a throw meter that measures in
degrees. There are several units available commercially. These units are a
great aid in set-up and definitely beat the “that looks about right” method.
For any type of precision flying, surfaces that travel equal distances are a
must. The following control surface travels are what I use on my own Yak.
These are a good starting point, but are by no means the only way to set up
the Yak. Start here and then adjust to fit your own preferences and style of
flying.
Elevator : 8-10 degrees low rate, no exponential; all you can get high rate,
60-65% exponential
Aileron : 20 degrees low rate, 30-40% exponential; all you can get high rate,
65-70% exponential
Rudder : 20 degrees low rate, 50% exponential; all you can get for high
rate, 80-90% exponential.
Again, this is just a starting point. Adjust to your liking.
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