Radio Control Jets - 2011/02

122 MODEL AVIATION
Also included in this column:
• Stabilization secret
• Preparation equals hours
of fun
• The Maverick flies
[[email protected]]
Radio Control Jets Jim Hiller
Teamed up for the Jet World Masters in Dayton, Ohio
Scott Harris built this Skymaster F-16 and flew it to earn his spot on the Jet World
Masters US team. That paint scheme is incredible, with extensive graphics and great
detail work.
David Shulman flew his beautiful DerJet Model Cougar to also
make the US team for the Jet World Masters. A quality aircraft
flown with a smooth stick is a hard combination to beat!
An impressive group of Scale jets about to be static judged at the Jet
World Masters US qualifier: Rod Snyder’s L-39 Albatros, Kim
Foster’s T-33, Jason Bauer’s MiG-15, and Andy Andrews’ P-80.
The finish on this Maverick is PPG base
coat/clear coat process in blue, white,
and green, mixed with aluminum. Sport
jets are great on which to try new
finishing materials before applying them
to Scale models.
QUALIFICATIONS FOR THE US team
that will compete in the International Jet
Model Committee (IJMC) Jet World
Masters are complete. The members were
selected in September at Litchfield,
Illinois, two days before the Route 66 Jets
event held at the Litchfield Municipal
Airport.
David Shulman, Scott Harris, Ron
Snyder, Jason Bauer, Kim Foster, and
Lewis Patton, along with alternates Bob
Bush and Andy Andrews, made it past the
final selection. They are a good mix of
experienced jet modelers who have a lot of
experience in World Masters, Top Gun,
and Scale Masters competition. The team
should do well.
The qualifier was held almost a year
early, to give the team members an
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February 2011 123
opportunity to build new jets for the event
that adhere to the IJMC rules. The weight
restrictions, bonus-points system, and
heavy use of gyros are different from what
we see in major Scale competitions in the
US, so the choice of aircraft will differ.
The IJMC Jet World Masters will take
place in Dayton, Ohio, at the National
Museum of the US Air Force July 24-
August 6. This promises to be quite an
event, with the best Scale jet modelers
from around the world attending. And it
might be the largest World Masters yet;
125 pilots are expected to represent 50
countries. For additional information,
check out the Web site.
At the September qualifier I participated
as a judge. It was a different role for me,
but it allowed me to appreciate the
variations in model types and setups for
competition; those factors do make a
difference.
Using a gyro on all axes can greatly
help pilots even out their flying, although
that wasn’t a major issue on the calm
flying day on which the qualifier was held.
Throw in some wind and turbulence, and
the advantages of gyros become obvious.
If your competitors have them and you
don’t, you lose.
My experiences with gyros have been
limited to nose-gear steering, quite awhile
ago, and lately on rudder only. My Bob
Violett Models BobCat has a gyro on the
rudder—what an improvement on a
bumpy day! Wing rock, which is
especially noticeable when flying past
trees, where the model gets bumped
around a lot, is almost eliminated when
I’m flying low.
I wouldn’t consider even setting up a
Scale swept-wing model such as an F-86
Sabre without a gyro on the rudder to
eliminate wing rock on landing and the
tail waggle that takes place during highspeed
flight on windy days. I believe in a
gyro on the rudder that much.
I guess it’s time to step up and
experience a jet flying with three-axis
gyro support, though—maybe on my old
T-33. They might make flying on a windy
day as smooth as it is on a calm evening.
We’ll see.
Winter is upon us here in the North, and
it’s our time for maintenance and building.
Last summer I flew my jets hard and
often, and they performed flawlessly the
whole time, thanks to good preparation.
I put more than 140 flights on my old
BobCat and 25-plus hours on the turbine,
during which time the only maintenance I
performed was brake and axle lubing. My
T-33 didn’t get quite as many flights, but
it performed equally well. So how does
one get these results?
My basic winter plan for the BobCat is
simple. I start by pulling the turbine, which
is a JetCentral Rabbit; 25 hours means that
it’s time for a trip back to the company for
inspection. And while it’s there I’ll have it
YS Parts and Service
www.YSengines.net
1370 Porter Drive • Minden, Nevada 89423
Tel 775-267-9252 • Fax 775-267-9690
• Bigger cylinder head for better cooling
• Three needle carburetor
• Same mounting pattern as the YS50ST
• New regulator design for ease of operation and reliability
• Proven fuel injection system for a consistent run & power
• Same mounting pattern as the FZ63S
• NEW steel lined backplate to minimize drag resulting in
better performance and increased horsepower
• NEW piston/sleeve design increases effi ciency
boost for more power
• Same mounting pattern as the FZ110S
!"#$%
& %'$()*
+,"#$%
!-'
./01
213/4567'
869/04:./4
;6</'41:4
='>3/%?
!-'!-'
./01./01
• Proven regulated fuel system for positive fuel fl ow
+,"#$%+,"#$%+,"#$%+,"#$%
• NEW larger cylinder head for better cooling
& %'$()*& %'$()*& %'$()*& %'$()*
• New regulator design for ease of operation and reliability
• Ring sealed crankshaft to increase crankcase
!"#$% !"#$% !"#$% !"#$%
Bore: 30.4 mm
Stroke: 25.8 mm
Displacement: 18.73 cc
Weight: 730 grams
Bore: 27.7 mm
Stroke: 19.0 mm
Displacement: 11.33 cc
Weight: 463 grams
Bore: 27 mm
Stroke: 26 mm
Displacement: 14.89 cc
Weight: 553 grams
Bore: 23.0 mm
Stroke: 22.0 mm
Displacement: 9.14 cc
Weight: 406 grams
FINALLY A
TOUGH
SUPER GLUE.
© 2010 Gorilla Glue Company
FOR THE TOUGHEST JOBS ON PLANET EARTH
®
1-800-966-3458 Made in U.S.A.
333 333 3
updated with the kerosene-start option.
Take good care of your power plant;
reliability is everything. This turbine ran
all summer with no issues. All dead-stick
landings were by choice—either
deliberate shutdown or plain running out
of fuel while flying with friends.
Dang you, Larry, Goose, and Frosty; I
just noticed a pattern there! You all had
bigger turbines and bigger fuel tanks.
Wait until next year!
The only time I remove the tailbooms
and the center wing section on the
BobCat is when I pull the turbine, so now
is my chance to inspect the internals. I
start with the long servo extensions
running the length of the tailbooms; there
are plenty of opportunities for those to
chafe against fiberglass along that run.
I pull on the hinges, check the
linkages, and perform a solid visual
inspection. I go over the stuff that is
normally hidden, such as the turbine
pump, solenoid valves, and smoke pump.
Then I check wires and fuel tubing for
issues.
The smoke pump got extremely weak
toward the end of the flying season,
because it’s getting old. Time for a new
quality replacement.
While I’m in there I check out all of
the fuel tanks. I pull them out and
visually inspect them for issues, leaks,
wear spots, and fuel-tubing condition.
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February 2011 125
Then I move forward to the pneumatics,
again looking for chafing and loose items,
and I review any operation issues I had
during the flying season.
I like to finish by putting a couple drops
of air-tool oil in the retract air system and
the brake system; I believe in lubrication.
Be careful on your oil selection; many
will damage the O-rings. Be sure to use only
a proper air-tool oil. If in doubt, order it
from a quality jet supplier; it knows our
needs.
I basically pull out all servo extensions
during this inspection, because I have to
remove the boards on which my radio
equipment is mounted to get to the nose
gear, steering servo, brake servo and valve,
and retract servo and valve. But a good
inspection is necessary every so often.
That silly little nut holding the retract
valve in place came loose the first summer I
had the BobCat, which resulted in its only
gear-up landing. Fortunately the grass belly
landing ended well; I never want to
experience that again. The only way to
inspect this is to remove the equipment
board; the servo and retract valve are
located under the main board.
Last I install new tires, clean and grease
the axle bushings, apply lube on the brake
O-rings, and then reassemble everything.
I take great care to properly route all
wires, air tubing, and fuel hoses, and secure
them as required. If I take my time and do it
right, I won’t have to do it again until next
winter. I should get more than 25 hours of
flying.
I can hardly stand that it’s too cold to
fly; once this BobCat is ready, I will be too.
Let’s plow the snow off of the runway and
go fly!
On the subject of shop work, the
Maverick turbine-conversion project is
finally flying. It’s fun! This model has
stepped up for the Wren MW-54 Mk III; it
displays good speed, good vertical
performance, and reasonable weight. This
older-generation Wren has only 14 pounds
of thrust, and the model weighs just more
than 16 pounds empty—not a bad powerto-
weight ratio.
I put time and effort into making the
Maverick a reliable and durable sport jet.
Some of that included exchanging the
original landing gear system for slightly
heavier retract units on the mains,
upgrading to 7/16-inch-diameter Robart
RoboStruts on the main gear, and installing
an all-metal nose gear retract unit from
Sierra Giant Scale, with one of its trailing
link struts. I hate marginal landing gears.
The original Bob Violett Models wheels
and brakes are still in place. The small 21/4-
inch main tires and brakes are performing
well at the model’s heavy weight.
Total fuel onboard is just short of 2
liters; a comfortable six-minute flight is
working out well with this jet/turbine
setup. However, all didn’t start well; four
of the first six flights resulted in dead-stick
landings.
It turns out that I had reversed the main
tank lines between the fill line and the
clunk line. But no harm was done, and
now the system runs great. That main tank
is hidden under the inlets, making access
and visibility to it limited. Don’t make my
mistake; the turbine will shut down in
flight.
I have only roughly five flights on the
model, so it isn’t dialed in yet. With the
increased wing sweep compared with a
stock Maverick, I am backing up the CG
until I get a comfortable setup for landing
approaches. With that, every flight gets
mix adjustment on landing gear extension,
flap extension, and general yaw and pitch
for knife-edge flight, but this is a trueflying
aircraft.
I plan to fly it some more during the
next two months and dial it in, and then I
should be able to share my experiences
with you. Setting up a model for maximum
flying enjoyment is an important process.
Until next time, let’s get out and fly! MA
Sources:
Jet World Masters
www.jwm2011.com
International Jet Model Committee
www.ijmc.net
Sierra Giant Scale
(440) 476-4885
www.sierragiant.com
Jet Pilots’ Organization
www.jetpilots.org
Jim Hiller
6090 Downs Rd.
Champion OH 44481
10
Why should you
become an AMA
member?
We’ll give you
10 reasons why.
F I N D T H E M A T
www.modelaircraft.org/
ten_reasons.aspx.
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