Radio Control Scale Aerobatics - 2011/04

Secure the gear inside your model
April 2011 125
[[email protected]]
Radio Control Scale Aerobatics John Glezellis
An Extreme Flight RC Yak-54 makes a low-level, knife-edge pass for the camera. When
flying such maneuvers, you must be able to trust your airframe as well as yourself! The
author has a few tips to help you get many years of flight from your aircraft.
Viewing the underside of John’s Hangar 9
Sukhoi, you can see that the ignition cable
does not come in contact with the cowling.
Make sure that no electrical components
touch sharp edges within your model; the
results can be disastrous!
The inside of Ray LaBonte’s airplane looks
stunning! By keeping all leads properly
secured, one can easily see what causes any
issues that arise.
Keeping extensions away from fuel lines is
a must. The fuel lines shown have been
properly secured, as have the various servo
extensions.
AS I AMwriting this, winter is in full swing.
Many of you might be working on projects that
you received under your Christmas tree, and
this is the perfect time to cover a few critical
areas of any given build.
To become a better pilot, there is no doubt
that one needs to practice. However, a pilot
must also trust both the equipment he or she is
flying and how his or her aircraft was
assembled.
Throughout the years I have seen and flown
many airplanes that various pilots built and
owned. In the end, one particular point was
clear: the airframes that lasted were those that
were well built and organized!
This month’s column pertains to safety and
how it can be linked to organization. I will
begin with the importance of properly securing
servo extensions, batteries, and receivers.
Since I’ll cover installing a battery, I’ll go
over a few options that exist regarding servos
and voltage regulators. I will complete our
lesson on organization by looking at an
interesting item that combines a switch and
voltage regulator in one unit, to keep your
model tidy!
Without further hesitation, let’s begin!
Getting Secured, the Easy Way! I stress the
notion that organization is a key area to pay
attention to within your model. Ensure that
every possible component is well secured.
Let’s look at a simple servo extension.
If you are building a giant aerobat for
(IMAC) International Miniature Aerobatic
Club competition, chances are that it uses
heavy-duty servo extensions that are 24, 36,
or even 48 inches and larger! I prefer to use
small cable ties or pieces of heat-shrink
tubing to keep extensions secured in
different locations within a given airframe.
My competition airframe for last year
featured two servos for the elevators (one per
elevator half) and two servos on the rudder that
were mounted in the tail. As a result, I had four
servo extensions that were to connect to the
receiver, as the servos were located in the tail.
I organize my servo extensions so that they
are perfect in length. I also separate my
elevator extensions from my rudder extensions
and route them separately from the tail to the
receiver; I route both elevator extensions on
one side of the aircraft and route the rudder
servos on the other side.
As I mentioned, I keep the extensions
secured using cable ties. And I keep them
away from any sharp edge within the model’s
airframe, to prevent damage.
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126 MODEL AVIATION
John secured the receiver in his Hangar 9
Yak-54 with two Velcro straps and Velcro
between the foam rubber and the receiver
and the tray. There are two security clips to
the left of the receiver. This must be done
between every extension connection, to
ensure that no servo becomes unconnected.
You can purchase small clips such as this one
at the local electrical-supply store. This
servo extension is for the left aileron servo in
the author’s Yak-54.
If you would rather use regulators but are
limited in space or do not want to mount
another electrical device, you can use
switches from PowerBox such as this Sensor
12. Two batteries plug into the switch, which
is then plugged into the receiver on two
ports. This unit also has a built-in regulator.
If your model features a “pull-pull” rudder setup, ensure that the
extensions are away from the rudder cables! In addition, always use
security connectors or, at a minimum, heat-shrink tubing over any
extension connection, to ensure that it will not become unplugged in flight.
Aside from servo extensions, make sure that no electrical components
come in contact with a sharp edge within the airplane. I have often seen
ignition cables cut because they have rubbed against a portion of the
cowling. Make sure that all openings made on the cowling are large
enough that this does not occur.
Also, make sure that all fuel lines are properly secured. If a given
item is not fastened, it can, and probably will, move in flight.
If a fuel line is loose within an airframe, what’s stopping it from
making contact with a part of the engine and/or exhaust system? If a fuel
line is fractured, your engine might quit, and that may result in the loss of
an airframe.
Not ensuring that the line is secure is a simple mistake that can
become costly within seconds!
Moving On: Talking Electronics! Now let’s review the proper way to
mount both the receiver and battery packs within your airframe.
I always use foam rubber between the receiver and the mounting
plate to which I fasten the receiver. However, I also use Velcro between
the mounting plate and the foam rubber as well as between the foam
rubber and the receiver.
Last, I firmly secure the receiver in place using one or two Velcro
straps, to ensure that the receiver does not come loose in flight. Never
use only a piece of Velcro to attach the receiver; always use Velcro in
addition to some sort of strap.
Batteries should always be secured to their mounting surfaces using
Velcro and, as with the receiver, have a strap around them. Consider the
battery (or batteries) as the life support of your model. I always use
Deans Ultra connectors between the receiver, the receiver and ignition
batteries, and the voltage regulators.
As I have stressed many times, redundancy is crucial. When building
a 50cc or larger Aerobatics airplane, use two main receiver batteries. If
you are using regulators, employ one per battery. Since we are on the
topic of batteries, let’s cover more fundamentals.
I’ve been using high-voltage servos on my giant aerobatic models for
quite sometime. Such units eliminate the need for a voltage regulator,
because each servo can receive the voltage that a two-cell Li-Poly battery
has to offer.
However, this can become costly, and some modelers don’t want to
use a high-voltage servo on the throttle.
Last summer I made a trip to Maine to visit Ray LaBonte, who is a
good friend of mine. We went out to the flying field, and I spoke to him
about one of his most recent builds.
On his giant-scale aircraft, he, too, is using high-voltage servos. But
he opts to use a standard digital servo on the throttle and have the throttle
servo plug into a Spektrum VR5203 voltage regulator.
This unit was primarily designed to be used with gyros on
helicopters. However, it provides regulated voltage protection for up to
two servo functions, with two input ports and two output ports.
The VR5203 is an extremely lightweight unit that can be used on a
throttle servo on your giant-scale model. It’s a unique little device!
Another option, if you want to add cleanliness to your aircraft, is to
use the PowerBox 12 Sensor switch, which has a built-in voltage
regulator within the switch. Two batteries plug into this switch, and the
switch plugs into the receiver on two separate ports.
This means that the current flow is shared between both connectors.
Using such a switch-and-regulator combination ensures a clean-looking
model!
I have covered the importance of a proper build on any given aircraft,
to promote longevity. A few steps, such as those I mentioned this
month, must be taken when transitioning from a small glow-powered
airplane to a 50cc or larger aerobat.
You must always spend time in the shop before taking to the skies.
When flying, the only thing you need to think about is performing that
perfect positive snap roll or two-turn positive spin!
My goal is to get you onto the flightline and winning!
Until next time, fly hard! MA
Sources:
Extreme Flight RC
(770) 887-1794
www.extremeflightrc.com
International Miniature Aerobatic Club
www.mini-iac.com
Hangar 9
(800) 338-4639
www.hangar-9.com
JR
(800) 338-4639
www.jrradios.com
PowerBox Systems:
Aircraft International
(732) 761-0997
www.aircraftinternational.com
WS Deans
(714) 828-6494
www.wsdeans.com
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