Radio Control Helicopters - 2010/02

Indoor flying is in full swing
[[email protected]]
Radio Control Helicopters Mark Fadely
Also included in this column:
• JR indoor festival
• Great Planes E-Fest
• Winter storage for nitro
helicopters
• Fuel systems
The OMI Fuel Magnet clunk system’s foam doughnut absorbs fuel
inside the main tank and then the aluminum pickup draws it into
the carburetor.
This is the fuel-system setup for a YS-91SR. The main tank (L)
supplies fuel to the header tank then through a clear filter before
entering the carburetor.
Jodi Knopic shows off the E-flite Blade CX3. It is easy enough for beginners to fly but has
killer looks that will excite even veteran modelers.
Chuck Baker is holding an Al Footdesigned,
all-foam Twirl gyrocopter that
flies great and cannot be stalled.
HELLO, EVERYONE. Can somebody
please high-five me for the fact that we
have indoor models today? In the middle
of winter I always ask myself, why do I
live in Indiana? But remembering that the
National Flying Site is just minutes away
takes the edge off my depression.
I’m envious of all those pilots who live
in warm climates. I guess you will never
have the thrill of flying off of a frozen lake
in your hometown. Did I use the word
“thrill”? I didn’t really mean that.
That is enough about my geographical
anguish. It is time to cover helicopters.
Indoor flying is in full swing. As I am
writing this, Jay Smith (MA’s assistant
editor) is writing about the 2009 JR Indoor
Electric Festival in Columbus, Ohio, held
November 6-9, 2009.
The inflatable dome where the event
was held collapsed awhile back and the
festival had to be canceled. This is the first
year that the gathering was held in a new,
larger dome.
Jay will have a full report on this event.
I hope many of you were able to attend.
The JR Indoor Electric Festival kicks off
the indoor flying season. Check out the
Web site and make plans to attend the
2010 edition.
You might receive this issue before the
Great Planes E-Fest takes place in
Champaign, Illinois. It is scheduled for
January 30-31, 2010. This is the biggest
indoor event of the winter, so if you can
make it out for this one, it will be worth
the effort.
Helicopters are welcomed at this gettogether.
E-Fest is mostly about having
fun, hanging out, and flying with your
buddies.
One of the most popular discussions about
February 2010 113
02sig4.QXD_00MSTRPG.QXD 12/21/09 9:45 AM Page 113
114 MODEL AVIATION
electric-powered helicopters involves
batteries. I have touched on some important
battery issues in past columns.
Technology keeps moving forward,
allowing cells to become lighter and more
powerful. My first electric helicopter used
an eight-cell Ni-Cd pack that weighed a
ton. The helicopter would hover and do
gentle forward flight for a four-minute
duration.
That would be considered pathetic
performance by today’s standards. Now the
top-performing helicopters can do wild 3-D
aerobatics for five minutes or be set up to
fly more docilely for roughly eight minutes.
Although we are in the midst of the indoor
season, I thought it would be good to
address preparing for upcoming outdoor
activities. When your outdoor helicopters
are resting, it is smart to check them over
well and make any needed modifications or
adjustments.
Nitro-powered helicopters have always
been popular for outdoor flying, but they
need a little more care with their fuel
systems and storage requirements. Fuel that
is left in an engine during the off-season
can gum up, causing issues when it is
started again in the spring.
When you know that your nitropowered
helicopter will be idle for more
than a few weeks, it is a good idea to run
all the fuel out of the engine and fuel tank
and then run some after-run oil through it.
This will help keep corrosion from building
up.
If corrosion is present during the first
start-up, you will likely do some damage to
the engine. The cylinder sleeve and piston
ring can become worn as the corrosion is
burned in the fuel mixture. That is like
using sandpaper on the inside of your
engine—not a good thing.
Fuel-System Setup for Nitro Helicopters: A
number of pilots ask, “What is the best way to
set up the fuel tank on my nitro model?”
There are several options available to deliver
the fuel to your engine with good consistency.
When a helicopter is in 3-D flight, Gforces
cause the fuel inside the tank to go
in all directions. Imagine that you are
mixing lemonade. You put the top on the
pitcher and shake it for a few seconds.
Now think about your helicopter doing the
same thing with its fuel tank.
As pilots, we expect our fuel systems to
perform flawlessly while our helicopters
fly in all orientations and speeds. That is
no easy task. Let’s take a look at some
fuel-system setups.
The oldest and most common type is
the muffler-pressure setup. In this system,
a line runs from the muffler to a tap on the
fuel tank. When the engine is running, it
forces pressure into the tank that helps
feed fuel to the carburetor.
The second type of fuel delivery is a
pumped type. In this configuration, there is
a pump with a regulator in the fuel line
before it reaches the carburetor. The pump
is generally more consistent in its metering
of fuel as the tank empties.
The fuel clunk that is inside the tank is
one of the most important parts of the
system. For many years, clunks have been
made from a weighted metal that is
designed to flop to any part of the tank,
following the G-forces that are being
applied. That works well, but the recently
designed OMI Fuel Magnet works even
better.
The Fuel Magnet does a wonderful job
of getting every last drop of fuel out of the
tank, and it holds a reserve so that the
engine won’t quit even if the clunk is
temporarily not drawing fuel.
James O’Neal of O’Neals
Manufacturing, Inc. (OMI) developed the
product. It is basically an aluminum insert
with an inlet hole that slips inside a small
foam doughnut. The foam soaks up fuel
and becomes saturated. It is heavy when
soaked with fuel, so it moves around
inside the tank with G-forces as would a
traditional metal clunk.
While it works well, be aware that the
foam is sensitive to exhaust gas. If you are
using muffler pressure in the tank, you
have to be careful not to leave the Fuel
Magnet exposed to the hot gases after a
flight. You can remedy this problem by
refueling your tank after a flight so that the
foam Fuel Magnet will remain submerged
and will not be affected by exhaust gases.
I still use the old-fashioned main/
header tank setup on some of my
helicopters. It is a proven system that
never seems to go out of style, and several
top pilots still use it.
A header tank uses the larger main tank
to feed a small auxiliary tank that feeds
into the carburetor. The header tank will
retain enough fuel, even when the main
tank occasionally takes in a little air.
It is difficult to get a tank set up so that
the clunk will always draw fuel. There will
be certain positions the helicopter can get
into that cause the fuel system to
momentarily run dry. This does not create
a problem for the header-tank approach or
the Fuel Magnet.
Although the OMI Fuel Magnet has no
header tank, the special foam sponge clunk
retains fuel and continues to feed the
system in the event that it draws air. It is
an ingenious invention that works. Check
your fuel system carefully, and change it if
it gave you problems last season.
I hope everyone enjoys the rest of the
indoor flying season. Don’t neglect your
outdoor models that are sitting on the
shelf. A little attention to preparing them
for the new season will pay dividends
when the weather breaks.
See you all here again next month. MA
Sources:
JR Indoor Festival
www.jriefestival.com
Great Planes E-Fest
www.gpe-fest.com
OMI
(256) 776-0879
www.oneals.com
Many companies now make prepainted electric bodies, such as
this beautiful T-Rex 450, at reasonable prices.
The Thunder Tiger header tank is one of the best available. The
fuel fittings are a snap to install and don’t leak.
02sig4.QXD_00MSTRPG.QXD 12/21/09 9:45 AM Page 114