122 MODEL AVIATION
Also included in this column:
• How to make Combat
participation grow in your
area
A look at alternative glow engines for Combat
[dongrissom@hilltopflyers.net]
Radio Control Combat Don Grissom
What happens when a small club wants to be a big RC Combat success? Have a builda-
thon featuring a great model.
A design that used to take 12 hours to finish can now be ready to fly
in roughly three hours, thanks to laser-cutting technology.
The Palomar club’s builds are a family affair.
David “MiG Man” Drowns preps the lasercut
kit. Almost the entire model is made
from Coroplast, which is extremely durable!
Right: This completed MiG from the build-athon
is ready for Combat; it is legal for Open
B and SSC. The finish of each pilot’s aircraft
should be personalized. Go for it!
AS WE START the new year, there is one issue that everyone appears
to be watching. This past year saw the end of the O.S. 25FX. This great
Combat engine was reasonably priced and turned up a good rpm. O.S.
has since come out with the 25AX, but there have been questions about
its ability to produce the rpm needed for our event.
I looked into some other engines out there and found a few great
alternatives. They may not be as good as a 25FX, but they will meet a
Combat flier’s needs.
One of these is the Magnum XL 28, which many Combat pilots have
been using for years. It meets the rpm requirements but has carburetor
issues at the high rpm at which Combat fliers run their engines.
The other problem with the XL 28 is vibration, which can cause the
fuel to foam and air to get into the lines. This is not an issue with some
models, but it might become one anywhere you have the engine close
to the tank. Suggestions have included dropping the propeller to a 9 x 5
for Open B.
Another alternative to the 25FX is the GMS .25. Something most
pilots notice about this engine is its price; it costs roughly half of what
the O.S. does. But sometimes a lower price means more hassles.
Scott Gilkey, who has done a lot of work with the GMS, has tried
many things that seem to be making progress toward turning it into an
excellent Combat power plant. Some of the test runs using a Master
Airscrew 10 x 4 propeller were at 13,600 rpm. After removing a shim,
Scott got the rpm up to 13,700.
Then he changed out the carburetor to the type used on an O.S. .32,
which gave him 14,200 rpm. It doesn’t equal an FX’s performance, but
01sig4.QXD_00MSTRPG.QXD 11/20/09 12:43 PM Page 122124 MODEL AVIATION
it’s close; with the rpm limit set at 14,000, this
would work very well.
With the Magnum, the GMS, and the O.S.
25AX, there are some good engines to use for
Combat. A forum on the RC Combat
Association Web site has suggestions for
setting up these power plants.
It seems like when I talk about Combat, the
topic is what is going on in the areas near
where I live, in Georgia. But in 2009, one of
the biggest areas of Combat participation was
California.
This past year has seen Combat grow to
more than 26 members. A big part of that
increase was making Combat easy for and
accessible to many people. The following is
from Glen Kratz, telling us how our event is
being cultivated on the West Coast.
“Several years ago when I decided to get
started in Combat, I did not know what
direction to go, where to start, what kind of
and where to get an airplane. Face it; I was
just a total ‘Rookie’ to the Combat arena.
Enter the Palomar RC Flyers Combat group.
“Palomar has been known as the ‘Combat’
club in the area but had also been suffering
from a decline in Combat attendance for
several years. The reasons for the decline were
varied but the biggest factor was lack of an
available, durable, attractive, easy to build and
fly airplane.
“David ‘MiG Man’ Drowns of Palomar
resurrected the Dave West designed MiG and
adapted it to SSC [Slow Survivable Combat]
specifications, drew up plans, made templates
and had a great flying airplane for Combat.
“Slowly other club members had picked
up on this airplane and were making their
own. The biggest problem was a lot of people
wanted one but lacked the skills, time or
ability to build one from scratch.
“Wanting to grow Combat and assist new
pilots in building a MiG, the idea of a build
party was brought up and before you know it
the MiG Build-a-Thon was launched. The first
few build parties were a marathon, as all the
parts had to be traced from tattered templates,
cut by hand, drilled, and glued before the
actual assembly could begin.
“The preparation process normally lasted
from early morning to lunch time, the builds
were ending somewhere around 9:00 pm,
additional builds were sometimes required to
finish the airplanes. During the builds Mr.
Drowns would build one for an example and
then that airframe would become a raffle prize
at the next contest. This quickly became the
most popular prize of the raffle.
“Richard Martin Jr., a budding Combat
pilot and MiG raffle winner, saw that having
to cut out all the parts first is the biggest
obstacle in the build parties. Richard’s family
owns Tri-M-Co, a metal fabricating shop, and
he offered to donate the use of his big CNC
laser cutting machine to cut out all the
Coroplast and wood for the build. The original
templates were converted to CAD drawings
and the plans were refined to reduce build
time and increase durability and performance.
“With the new CAD files loaded and a few
tweaks to a machine that normally cuts one
inch thick plate-steel, the Palomar build
parties were kicked into high gear. What was
taking half the day of prep time for a few
airplanes, now could be done for numerous
planes in a few short hours.
“Without Richard’s generously donated
machine use and pre-cutting parts it would be
difficult for a new builder to complete an
airframe in one day. The build parties had
now become a viable way to get an airplane
together in about a day ready to fly for
Combat.
“The current build parties are usually
scheduled one month before the next Combat
event and are set-up for 14 aircraft, both SSC
and Open-B versions are available for the
builds. Through the support of several local
hobby shops that provide a club discount for
parts and the countless hours Mr. Drowns
spends prepping and putting the kits together
one can sign up and build a MiG airframe for
the unbelievable price of $40. This price is
exactly what it costs in materials; all labor is
donated by the dedicated Palomar RC Combat
group.
“The build parties are a huge success and
the slots go quickly and are heavily attended
by enthusiasts interested in Combat. The build
parties have grown and are now incorporating
Treneff R/C’s Battle Axes.
“Todd Melton of Palomar and Andy Erwin
of MidCal Spads have been working on new
SSC Coroplast designs and have several WW
II aircraft like the P-40 Warhawk and the
Japanese Zero in prototype flying stages, so
there is a constant development of new types
of aircraft. The new designs once they are
perfected will work their way into the builds.
“With the success of the build parties and
through some Combat demonstrations and
networking with other local clubs, Combat in
California is growing fast. With some basic
advertising via flyers to other clubs and
posting at local hobby shops, Combat events
are becoming the thing to go watch by RC
enthusiasts and at any given event there is
always a large crowd of spectators.
“What used to be four contests in southern
California has now expanded and there have
been three contests added to the schedule this
year, and next year’s schedule will have two
more new contests and include three clubs
new to Combat. Most of the contests’ entries
have doubled and currently field at least 10
contestants for Open-B and upwards of 20 for
SSC. There is also talk of a ‘West Coast
Nationals’ event.
“The work that has been done by everyone
associated with Combat here in California has
laid the ground work for keeping Combat
popular for years to come. The new
enthusiasm has renewed interest in Combat
veterans and brought them out from
retirement to help steer the growth and pass on
their skill and wisdom.
“Combat pilots are once again traveling up
to 600 miles to participate in the other Combat
events in California. There are numerous
father/son teams and a number of young
Combat pilots that are almost ready for
contests.
“I am excited about the future of Combat
locally as I like to think California has become
‘the tip of the sword’ in promoting and
growing RC Combat.”
Thank you, Glen, for that great success
story. Sharing the fun of aeromodeling in a
group at all levels increases participation.
Expert building sessions can be as popular as
the beginner building sessions.
Introducing different aircraft types is
helping maintain modelers’ interest. Sharing
the success with other clubs is feeding the
need that every part of the country should
have: to fly RC Combat! MA
Sources:
O.S. Engines
(217) 398-3630
www.osengines.com
Magnum
(714) 963-0329
http://magnum.globalhobby.com
GMS
(217) 398-3630
www.bestrc.com/gms
Radio Control Combat Association
www.rccombat.com
Palomar RC Flyers
www.palomarrcflyers.org
Palomar Flyers Combat
members.cox.net/pfcombat
TreneffRC
(731) 217-2868
www.treneffrc.com
Mid Cal Spads
www.midcalspads.com
Call Toll Free:
888-829-4060
7414 Burton Drive, Liberty Twp, OH 45044
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Scale Documentation
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North American F-86 Sabre
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