Radio Control Jets - 2004/02

138 MODEL AVIATION
I HAD AN OPPORTUNITY to fly the new
Tango Almost Ready-to-Fly (ARF) jet from
Mecca Models. The Tango is a smaller
model, with a wingspan of 67 inches,
designed to be powered by 11- to 18-poundthrust
turbines.
The general layout is the now-popular
twin-boom arrangement with a turbine
mounted near the wing’s trailing edge. Unlike
many similar designs, the turbine is mounted
out of sight inside the aircraft with inlet ducts
leading to the turbine. No tailpipe is required
with this setup, thereby reducing complexity,
weight, and cost.
This is the first of the turbine kits to come
from Mecca Models. Don Kanak of Planes
Plus, the distributor of the Tango, is offering
the kit with packages that include PST 600
turbines, Robart landing-gear setup for the
Tango, and wheel and brake systems. The package prices make this
an affordable jet.
Don allowed me to fly his Tango many times at the Heart of
Ohio Jet Rally, and what a pleasure it was to fly this model. His
Tango was powered by a 12-pound-thrust PST 600 turbine and
equipped with the Robart retractable landing gear. With this setup,
the Tango’s overall weight was less than 16 pounds. Add to this the
fact that the model is equipped to hold more than 100 ounces of fuel.
The Tango comes standard with flaps. Don has developed a
speed-brake option for those who want additional drag devices to
help set up for landing. This model was equipped with the speed
brake.
The Tango I flew was factory-painted in red, white, and blue.
Don’s other Tango—the one he flew all weekend—had the red,
white, and yellow color option. This second Tango was powered by
a JetCat P-80 and had the fixed-landing-gear setup.
That’s enough about the basic model. How does it fly? I enjoyed
the Tango. The power with the PST 600 was sufficient; there was
plenty of power for normal flying. I found during hard aerobatics
that I preferred to leave the throttle at full power to carry momentum
for the next maneuver, but it was not a real issue. With the large fuel
tanks, I set the timer for 10 minutes and flew all 10 minutes on
every flight.
The wide-track landing gear on the Tango makes ground
handling predictable, even in a crosswind. Once off the ground you
come to really appreciate the Tango. The layout aligns the turbine
centerline close to the wing centerline. It is a pleasure to fly through
all speed ranges, as the trim does not change with power application.
Combine this with the symmetrical airfoil and you have true
Pattern-flying characteristics. If you enjoy pulling your loops as well
as pushing outside loops, you will appreciate the Tango. It loops
inside and outside equally well.
Let’s get on to rolling maneuvers. I noticed some roll coupling in
knife-edge flight, but this was easily mixed out with minimal
offsets. The model holds knife-edge reasonably well and allows
those long, drawn-out slow rolls or point rolls. Minimal downelevator
is required for inverted flight when properly balanced. Snap
rolls break cleanly and recovery seems equally repeatable.
Slow flight is an important area of a model’s flying regime. The
Tango has a thick, symmetrical airfoil that slows well, and with the
flaps it provides adequate drag for a nice approach angle. I found the
optional drag brake unnecessary, but I did use it on a few landings
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
Dave Malchione owns this F-4 Phantom. When joined in flight by two or three other
Phantoms, it is a show you will not soon forget.
Joe Lupton can build as well as the best Scale modelers. His F-
86 Sabre has to be seen to be appreciated.
The new Tango ARF sport jet model from Mecca Models brings
precision flying to Radio Control jets.
02sig5.QXD 11/25/03 9:52 am Page 138
and it does increase the approach angle.
Don’t be misled; this model breaks
cleanly when stalled and is optimized for
Pattern-like flying. The stall is predictable
and recovery is not an issue.
The Tango is a good addition to the
ARF models available to the sport turbine
modeler, especially those who can
appreciate an airplane with good,
symmetrical Patternlike flying character.
Check out the Planes Plus Web site at
www.planesplus.com for additional
information and package deals that make
this an affordable sport jet.
One thing I noticed last summer was the
variety of landing-gear setups on the jet
models. With minor landing-gear changes,
many of these models could be made
friendlier on landing. Some of these
changes include the length of the nose gear
and the stiffness of the landing-gear
springs.
Suppose a pilot has a model that he or
she can land well but the model touches
down a little fast, hurried because it is a
little higher than normal. Off it goes,
bouncing down the runway; each bounce is
progressively larger than the previous one.
What caused this, and why?
Let’s start with how a wing creates lift.
The wing’s angle of attack is what we
change as we slow the model by pulling upelevator
during the landing flare. This
increased angle of attack is what allows the
wing to make enough lift to support the
weight of the model as the airspeed
decreases. If there is too much elevator, we
increase the angle of attack and get more
lift; the model climbs until the airspeed
slows to the point at which the lift equals
the weight of the aircraft.
Back to the landing gear, I will address
the effects caused by the length of the nose
gear. My preference is to set my model near
level. I measure the difference in height of
the wing leading edge and trailing edge,
and then I set the nose-gear length so that
the wing’s leading edge is roughly 1⁄4 inch
higher than the trailing edge.
Take this measurement near the centersection,
relatively close to the fuselage.
This will make the wing slightly negative at
the tip if washout is present. I use this setup
because almost all of my flying is off of
pavement.
One reason for achieving such a level
setup is to improve crosswind capability.
The wing is making little or no lift on the
takeoff roll or landing rollout, so the full
weight of the model is on the tires,
providing maximum traction to deal with
the crosswind. The negative is that my
takeoff rolls tend to be a little longer, as the
elevator must lift the nose to take off.
The second reason to set up a model
level is so it can land at a greater airspeed.
You do not have to get deep into the flare.
Give it lots of elevator and make a bouncefree
landing.
When landing too fast with a long nose
gear, the model touches down on the nose
February 2004 139
gear first. This is referred to as a
wheelbarrow landing. The airplane pivots
around the nose gear until the main gear
touches. The wing is now at a greater angle
of attack, but the airspeed has not been
reduced so it goes back up into the air. If
you catch it on the first skip, all is okay and
it is just a bounced landing.
If you don’t catch that bounce, things
can get nasty. The second bounce results in
the model launching up at a harder angle.
As each following bounce launches the nose
up at progressively greater angles, the
landing gear breaks or the wing finally stalls
and rolls over on its side, wiping out the
landing gear from the side loads.
What happens during a hard bounce is
that the nose-gear spring compresses, then
all of that stored energy releases, launching
the model’s nose up at a steep angle and
setting up that dreaded series of hops that
develop into broken models. Why do we
have such a strong spring in the nose gear? I
don’t know.
Let’s consider how the weight of the
aircraft is carried on the landing gear. On a
typical 21-pound empty-weight model the
main gears will each support roughly 10
pounds of the airplane, leaving the nose
gear to support approximately 1 pound.
Shouldn’t the nose-gear spring be roughly
one-tenth the strength of the main-gear
springs?
It sounds simple and it is. This is why I
like to install a weak spring in the nose-gear
strut, to reduce this tendency to launch the
model after a blown landing.
I have discovered another nice feature of
a soft nose-gear spring. You can watch it
compress under braking to help you judge
your brake application. The nose-gear strut
will collapse with a soft spring, providing
an indication of how hard you are applying
the brakes.
Normally we don’t know that we are
braking too hard until the tires lock up, flatspotting
the tires and causing a loss of
directional control. You can watch the angle
of the model as the nose dips, collapsing the
nose-gear strut from braking when using a
soft nose-gear spring. Try it and I think
you’ll like it.
Model setup and what each of us prefers
is based on how we fly, what we fly, and the
fields from which we fly. I would be a big
fan of a longer nose-gear strut if I were
flying my model from grass. It reduces the
load on the landing gear as the airplane
picks up speed, transferring the load to the
wing and shortening the takeoff roll. As I
mentioned, I fly my jets off of pavement, so
the setup discussed is biased toward
pavement flying.
It’s time to pack the car and head for the
field. I gotta burn some Jet-A. MA
Micro-Mark has more than 2,600 name-brand and hard-to-find
tools and accessories…many at discount prices. You’ll complete
your projects in less time with more professional results!
340-3226 Snyder Avenue
Berkeley Heights, NJ 07922-1538
NAME
ADDRESS
CITY
STATE ZIP COUNTRY
5”DISK SANDER
To order our catalog, send $1 and this coupon to:
1-800-225-1066 • www.micromark.com
Please say you saw our ad in the February issue of Model Aviation.
MICRO-MARK’S
got it !
#82889
02sig5.QXD 11/25/03 9:53 am Page 139