Radio Control Combat-2011/11

November 2011 121
Quick and easy bladder tank
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Radio Control Combat Don Grissom
You will notice that the liner is sticking
outside of the stopper. Connect the
muffler to the pressure fitting and the
line from the carburetor to the copper
tubing.
You will need a tank such as a 6-ounce
Sullivan, a pressure fitting, and an 8-
ounce baby bottle liner.
Many types of airplanes
are flown in Scale 2948.
Also included in this column:
• 2011 Combat Nationals
EARLIER THIS YEAR I decided to change
my airplane back to a design that had I used
once before, which flew well. The Falcon,
designed by Lee Liddle, is a flying wing with
the engine mounted on cutting-board material
on the front. In past designs I had always used
a bladder system that would push the fuel to
the engine instead of using the back pressure
off the muffler.
After attending to the Nats, I talked to
Sam Windsor and he showed me a bubbleless
tank. I have seen some people use them for
some of the scale designs but never thought
about using them for my open or SSC
airplanes.
The design is simple to build with a few
supplies that you can obtain from a hobby
shop and a grocery store. You will need a
tank; round tanks seem to work best because
the bladder is also round.
I used a 6-ounce Sullivan round tank. The
Sullivan tank is nice because its bubble is at
the top. You will need a pressure fitting,
which in this case was a Du-Bro number 241.
Last, you will need to get some disposable
baby bottle liners. I purchased the Playtex
brand 8-ounce standard liners. They will last
for a long time so if you know someone with
a baby, then you’re in luck.
The first thing you will do is drill a hole in
the bubble at the top of the tank that allows
you to screw in the pressure fitting. You need
to use some glue to hold it in place and
prevent leaking. From this point you will take
a bottle liner and push it into the tank leaving
some of the liner on the outside.
Since you only need one line going into
the tank, only put one tube into the stopper.
The extra hole will need to be closed off
with a screw and some glue. Place a small
piece of fuel tubing on the end of the copper
tube so that it will not damage the liner.
After your tank is complete, mount it on
your airplane with the bubble on the
bottom. This way any fuel that goes
through the pressure connection can be
drained. It is a good idea to use a syringe to
fuel the tank. This allows you to remove all
of the air from the bladder before putting
fuel in the tank.
Because there will be no air in the tank
and there is only one way for the fuel to go
in, you will not get air in the line.
Additionally, you will use all of the fuel in
the tank unlike using a clunk.
After some testing, this setup works
well on my airplanes. The other advantage
to the system is that you can put the tank
sideways and it will still work.
Every summer we have one of the biggest
events of the year at the National Flying
Site in Muncie, Indiana. The RC Combat
Nationals are a four-day event with 40
rounds of Combat.
I have been going to the event for many
years now, and although this one had fewer
people attend, it was not without good
flying. I had decided to have a new fleet of
airplanes ready this year, but after looking
back I realized should have done a little
more work before I went.
Normally, one of the top pilots at the
event has been Brian Gilkey, since he has
won most of the Nationals in the past five
years. This year he was not able to make it,
so he left it up to Eric, his younger brother,
to keep the winning tradition alive.
We started out the week with two days
of both Slow Survivable Combat (SSC) and
Open B Combat—five rounds of each for
each day. This biggest contest of the week
was SSC with 13 pilots. William Drumm III
got off to a fast start with some high scores,
although he was not the only one. Andy
Runte and Bill Geipel got off to a good start
as well.
I was not that lucky; right away I had
some engine problems that I never had in
the past. I flew this design earlier in the year
at another contest and had few problems,
but this was not going to be my day.
I ended up pulling out of Open B to try
to resolve my engine issues. After the first
events were done, we ended up with a new
pilot on top this year in William Drumm III.
He has his own design that he flies. It turns
fast but he is also a good pilot. One thing I
noticed is that he does not seem to get into
trouble by staying in the furball too long.
After completing the official classes, the
last two days were for Scale 2948 and
Limited B. After experiencing so many
issues, it was nice to get to fly this time. I
had few problems with my Scale models.
I was flying the KI43 Oscar, which is
sold by Chris Handegard. This is a good kit
that I have flown for many years. He also
has some other great designs. One
advantage that Eric Gilkey had this day is
that William Drumm did not fly Scale—at
least not at that time. This gave Eric a
chance for a first-place finish.
Since we did not have many hard midairs,
we were able to fly all 10 rounds in one
day. This is not normal; Scale can have
some of the worst damage. After the 10
rounds, Eric Gilkey ended up with a firstplace
finish and Nicholas Windsor from
Florida came in second. Rick Wise placed
third.
The final event of the week was Limited
B. Throughout the years this has become a
great event since it is slower than Open B
but fast enough that you do not have issues
with wind and getting your airplanes in the
air.
We started off the day with one of only
two pilot-line infractions for the week. The
weather had been nice, but on this day the
wind picked up slightly. After flying five
rounds Friday, we completed the remaining
rounds Saturday and then packed for the
drive home.
If you are going to travel to a contest next
year, this is a great one to attend. MA
Sources:
Radio Control Combat Association
www.rccombat.com
NatsNews and scores:
www.modelaircraft.org/events/nats.aspx