AirBorne Models’ TAMEcat EP ARF

     

This review of the AirBorne Models TAMEcat EP first appeared
in Park Pilot magazine. Park Pilot is the official magazine of the Academy of
Model Aeronautics (AMA) Park Pilot program. Details about the Park Pilot
program, an AMA membership class for pilots of small electric airplanes, are
available at: http://www.modelaircraft.org/parkflyer.aspx . However, space is very limited in Park Pilot and the review was, by
necessity, too brief to do this airplane justice. This is an expanded version.

The TAMEcat EP meets all the
aircraft requirements of the Academy of Model Aeronautics’ (AMA) Park Pilot
Program. The aircraft weighs less than 2 pounds (the Program’s upper weight
limit) and has a level top speed just, barely just, under 60 mph (the Program’s
upper speed limit). For complete Park Pilot aircraft details, follow this link.

The AMA Park Pilot
Program offers non-AMA members the opportunity to become AMA members at a much
reduced cost. Park Pilot membership includes a great magazine “Park Pilot”,
$500,000 personal liability insurance, $2.5 million liability insurance for the
flying field owner (see insurance details) and membership in the world’s
largest sport aviation association – the AMA. For complete information and
details about Park Pilot membership, just click here. 

Many 1.5 lb. airplanes capable of safely flying inside a small
park field can be pretty boring. This is especially true if the airplane uses a
flat-bottom airfoil wing for extra lift and stability. Almost all such
airplanes are so tame as to be uninteresting to any but the newest Park Pilots.
However, despite its TAMEcat name, this aircraft “tain’t” one of them!

Based on a very original 40-size, glow-powered basic trainer
design by Jeff Troy, the TAMEcat EP combines jet looks with all the traits of a
good basic trainer: light weight, large flat-bottomed wing, excess vertical fin
area and an overly large horizontal stabilizer, into a single aircraft that
turns out to be, not a trainer, but an advanced scale airplane that can own the
sky when you push it.

Unlike its larger brother, the TAMEcat
40 ARF reviewed in Sport Aviator’s “On The Flight Line” section, The
TAMEcat EP is definitely NOT a basic trainer. However, it is a great second or
third airplane. The TAMEcat EP is exciting to fly, climbs like a rocket, flies
fast enough in a small field for even the strong of heart, flies well inverted
despite the flat-bottom wing and builds in an afternoon. But it also slows done
very nicely, has no tricks to play, is not “snappy” even when pushed beyond the
envelope, looks great in the air and lands like a trainer.

     

Photo 1      Photo 2

Not only is the TAMEcat EP a blast to fly, it is fun to
build because it builds more easily than a trainer. The 39.5 in. wing is one
piece with the ailerons hinged but not installed. That makes it easy to mount
the control horns for the twin aileron servos (photo 2). AirBorne Models has
already removed the covering over the stabilizer / fuselage gluing area. All
three “tail feathers” utilize interlocking construction that adds strength and
insures proper alignment (photo 1).

The factory bolt holes in the wing align with the installed
blind nuts in the fuselage while the front hold down is part of the wing’s
structure. The motor mount is factory installed. Heck, AirBorne Models even drilled the control horn mounting holes in all the control surfaces. When have you seen that before?

Assembly

     

Photo 3     Photo 4

This is also an extremely easy airplane to build straight
and fast. However, the instructions don’t do a lot of explaining. There is
precious little text but the photo close-ups do show everything. Study them
carefully to get the parts orientation right.

But as the TAMEcat EP is almost entirely built when you open
the box, maybe instructions are not all that important anyway. Note the
covering is already removed from the fuselage stabilizer mount. While not
shown, the covering has also been factory removed from the same area under the
stabilizer.

Photo 5

Photo 5 shows everything needed to complete the one-piece
wing. The aileron servo mounts were perfectly aligned with the pre-drilled
control horn mounting holes in the ailerons. The aileron control rods were also
factory made and fit perfectly. The original concept was to use the “Y” cord
shown but that was later changed and the “why” is covered in the flight section.

The E-flite S-75 Sub-Micro
servos move quickly (12 sec/60 deg.) while producing 17.2 oz. /in. torque. They
were fast enough to stay ahead of this airborne performer yet had more than
enough power for control.

Photo 6

Refer to the wing photo and make your wing look like that. The
factory pre-assembly is so comprehensive that those are almost the only
directions needed to build the wing! If you are using one of the newer, more
powerful but smaller sub-micro servos like the EFLR S75, in this airplane, you
might have to raise the aileron mounts so that the servo arm clears the wing
bottom. The S-75 servo has the power of a mini, around 17 oz. in. of torque but
in a 7.5 gram sub-micro package.

Photo 7

If your servo does not extend far enough out of the wing to
clear the servo arm, cut four pieces of 1/8 x 1/4 in. birch strips to the
proper size and glue over the four factory installed servo mounts; two per wing
side (photo 6). Then install the servo as usual. The aileron control rods are
factory cut to the proper lengths and threaded both sides. Connect as shown in
photo 7.

As mentioned photo 7 shows the ailerons “Y” corded, which
was how the first flights were made. If you want to use flaperons, eliminate
the “Y” cord. Then program the transmitter for flaperons. Install the ailerons
with the Mylar hinges. For complete hinge installation details, read the Sport
Aviator article “Installing Mylar Hinges” in
the Flight-Tech Section.

Photo 8

After completing the wing, the fuselage is next. The first
assembly step on the 29 in. long fuselage is to install the rear flight
surfaces. Interlocking construction insures everything is built straight. This
unit construction is very strong (proven in flight tests) yet also very light.
The covering over the bottom of the horizontal stabilizer and its fuselage
mounting (photo 8; under the wheels) area have been factory removed so no
cutting is needed.

Photo 9

Apply 12-minute epoxy to the stabilizer bottom with an epoxy
brush (cheap, disposable 1/2 in. brushes sold at all hobby stores) and install
it on the wide fuselage area as shown. A Tip: Keep the epoxy at least 1/8 in.
away from the vertical fin slots to protect against accidentally gluing the
vertical fins in place while installing the stabilizer. Position the
stabilizer, temporarily insert both vertical fins (no adhesive), align and
weight the stabilizer as shown. Make sure
it is parallel to the wing saddle. This is all-important to insure this
airplane will not roll with elevator input.

Photo 10

Once the stabilizer is cured, install the elevator using the
Mylar hinges. Again, read the Sport Aviator article linked above for details.

Photo 11

Protect the LIGHTEX covering from the epoxy adhesive with
low-tack masking tape as shown in photo 11. The LIGHTEX covering, with its
pre-printed panel lines, access hatches and other surface details, is just too
perfect to stain with epoxy. Attach the elevator control horn to the elevator
using the factory marked screw holes. The factory made elevator control horns
fit perfectly.

Note in photo 11 that both the rudder and elevator servos
are mounted exposed on the fuselage top. Both the elevator and the two rudder
control rods are factory cut to the correct length but the servo end must be
bent as shown. All the threaded control rods were factory cut and only required
bending at the servo end.

Photo 12

Now is the time to mount both vertical fins and both
sub-fins permanently with 5-minute epoxy. Do one at a time. Install each of the
top vertical fins using a triangle to insure both are vertical to the
stabilizer. Insert the epoxy into the slots using an epoxy brush. Once the
adhesive is applied inside the slots, remove the masking tape and insert the
vertical fin or sub-fin. Be sure to keep it vertical while the 5-minute epoxy
sets up.

Photo 12A

Photo 13

The TAMEcat EP includes an AirBorne Models KM0283010 outrunner
motor that bolts into the TAMEcat’s motor mount. This motor produces 205 Watts
of raw power @ 12.4 Volts using the recommended 11.1-Volt, 3-cell Li-Poly battery. How much power is that? A trainer
should have around 80 Watts of power per pound while an aerobatic airplane
needs about 150 Watts per pound. The TAMEcat EP, flight ready, weighs 23 ounces
meaning it has the power rating (143 W/lb) of an aerobatic performer in a scale
body. The extra power is a big reason why this attractive airplane performs.

The Electronic Speed Control (ESC)
used to control this power is Extreme Flight’s “Airboss” rated at 35 Amps. At
full throttle, the motor only draws 18.1 Amps meaning that a 20-Amp ESC would
have been enough had I one on hand. But the Airboss provides extra reserve
capacity and is fully programmable. It weighs the same as a 20-Amp unit and,
most importantly, was here when I needed it. If you are using a programmable
ESC, set it for a “Hard Brake” so that the propeller stops and folds quickly
when the power is shut down.

     

Photo 14      Photo 15

Like all Electronic Speed Controls, the Airboss requires
that the motor connectors be soldered onto the three motor and ESC leads. With
a block of wood, either a soldering iron or 145 Watt heat gun and water spray
bottle, this becomes an easy task. The water is used to cool the connectors so
that the leads will not slip out while the solder is still molten.

Photo 16

The motor mount exactly matches the AirBorne Models motor.
The four matching mounting holes allow the motor to be placed inside the wood
mount structure. Put a small amount of removable thread locking compound on
each bolt. Make sure that no compound reaches inside the motor; apply it only
to the bolts themselves to prevent this.

     

Photo 17      Photo 18

Once the motor is mounted, install the propeller adaptor.
Even here, applying some thread locking compound is a good idea. Apply the
compound inside the motor shaft hole on the propeller adaptor.

     

Photo 19      Photo 20

After installing the adaptor, attach the spinner and backplate
and use the assembly to line up the cowling. The airplane uses a folding 10 x 6
in. propeller that assembles with two bolts (photo 20). Align the cowling with
the spinner before mounting the
propeller blades unless you have three hands. Then drill the four cowl mounting
holes trough the factory pre-drilled cowl holes and into the firewall sides.

     

Photo 21      Photo 22

Assemble the complete front end. The ESC is placed in the
cooling air flow in front of a
former. The battery goes behind that
former using a hook and loop strap fastener to keep it in place.

Photo 23

Add a second strap to insure the battery stays put during
this airplane’s wilder rides. The battery connectors must pass through the fuselage
former so enlarge the hole in the former to ease the connector’s passage as
shown in the above photos.

     

Photo 24      Photo 25

The radio system is the Spektrum DX 6 using the AR 6000
receiver. This computer system operates on 2.4 GHz so radio interference is
never a problem. The receiver mounts under the rear top hatch and requires an
extension from the front on/off switch to reach its “throttle” input. I strongly
suggest using an ESC equipped with an on/off switch as this airplane’s battery
connections are hard to disconnect without violating the propeller’s Arc of
Danger. A “bumped” throttle during battery disconnect can ruin the entire
afternoon if the receiver is still alive during the process. Use a switch!

The receiver is located inside the large, top-side hatch.
The hatch cover is held in place by four wood screws. Photo 9 shows the cover
held in place by some tape as it arrives from the factory. There is a lot of
space under the hatch.

     

Photo 26      Photo 27

The TAMEcat EP’s underside has two removable hatches that
are held in place by nylon rotating arms. The rear most hatch is for battery
access. Photo 26 shows the hatch in the closed position while photo 23 above
shows the hatch removed and the battery in place. The forward hatch, shown in
photo 27 with the cover removed, allows access to the ESC and the radio on/off
switch. This area is usually kept closed unless a problem develops.

Photo 28

Unlike most RC aircraft, the TAMEcat EP has zero clearance
for wires, receivers, etc. once the wing is in place. Make sure that all wires,
including the aileron servo wires, have a home located under the wing.
Everything must fit inside the fuselage as even the smallest protrusion will
prevent the wing from seating properly.

Photo 29

Look closely at photo 29. You will note that there is a
clear, narrow plastic wing cover that protects the wing from the two hold down
bolts. Don’t forget this piece. Hold it in place with s few drops of thin CAA.
Bolt the wing and protector in place, and then sparingly apply two drops of the
adhesive to the center section. Do not allow any adhesive even near the wing
bolt area. Unbolt and remove the wing after the adhesive has dried. Remove the
bolts and apply a few drops along the rear edge as well as at the two corners.

The TAMEcat EP finished out at exactly 23 oz. With its
large, high-lift wing, this made for a very light 12.1 oz. per sq. ft. wing
loading. This is much lighter than most basic trainer which average in the
16-18 oz. per sq. ft. range. As a result, slow flight can be really slow and
vertical climbs are more fun, and higher, than most pilots would expect.

Flying

     

Photo 30      Photo 31

The detailed LIGHTEX covering really sets this airplane off.
It looks like I spent hours detailing the airplane with access panels, hatches
and panel lines. Nope, I surely didn’t. It came that way. This airplane and its
glow-powered big brother are unique in this respect.

The TAMEcat EP also comes with landing gear for use on paved
surfaces but leave the gear off when flying from grass since the propeller
folds. It is an easy airplane to hand launch as the wide fuselage provides many
safe gripping surfaces.

Photo 32

At full power, the TAMEcat EP jumped out of the hand launch.
The climb rate was incredible. Since the trim was acceptable, if not perfect, I
let the vertical climb continue on up to about 300 ft. while holding in some
right aileron to compensate for the slightly out-of-trim condition. Pushed to
level, the airplane then accelerated very quickly. While its top speed is not dangerously fast, estimated at 50 mph,
the aircraft gets there right now; acceleration
is almost instantaneous. A few clicks of aileron trim and we were ready to
rock.

Photo 33

The airplane flew straight lines as if it were running on
Union Pacific tracks across the dry lake beds. Even in a gusty crosswind, the
TAMEcat EP penetrated the wind with no bumps or course deviations. It “pointed”
like an old-time Pattern airplane; going exactly where it was told to go with
no questions or course changes. This is impressive performance for any airplane,
but amazing performance for a Park Pilot aircraft.

Photo 34

Each full roll took about 1.5 seconds. Because of the
flat-bottomed airfoil, extra “down” elevator was required after the third roll
to maintain altitude and a positive angle of attack during
the inverted parts of the rolls. If the airplane does lose altitude during any
maneuver, the pilot can easily get it back because the TAMEcat EP has unlimited
vertical performance. Point it straight up, give it all the electrons at once,
and then watch it shoot upwards until you suddenly realize “Hey, I can’t see it
anymore”.

Stall turns require half throttle for the small rudders to arc
the airplane over. Surprisingly, the small rudders cause the airplane to bank
without aileron input even though the wing has no dihedral. Snap rolls are slow
so stopping at wing-level is easy.

Using the factory control throw settings, rudder 0.31 in. aileron
0.25 in. and elevator 0.40 in., the airplane can’t maintain knife-edge flight
and will not snap or spin. Experienced pilots should set the elevator movement
at 1/2 in. and the rudder at “all you can get”. The ailerons work best at 0.4
inches movement. Put in 40% Exponential for the rudder, 35% for elevator and
25% for aileron control to smooth out regular flight.

Spins and snaps now become fun and while the TAMEcat EP
still can’t maintain level knife edge flight, the extra rudder authority slows
the descent rate and extends the maneuver across the length of the average
flying field. Use mixing to dial out any roll coupling and knife-edge walking
(to the canopy).

     

Photo 35      Photo 36

Inverted flight is incredible for a flat-bottom wing
airplane. Not only will the TAMEcat EP maintain level inverted flight with
little “down” elevator input, this airplane can do multiple reverse outside
loops (inverted loops from the bottom).

How about trying multiple vertical eights? An outside half
loop first, followed by an inside half loop on the top and then, instead of
pulling over the top, push into another half outside loop and another half inside loop. By now the TAMEcat EP is so far
up there it is getting too hard to see. So, pull over the top and complete the
twin vertical eights back to level flight.

Because the airplane tracks its line so well and has so much
reserve power, large, regular loops are so simple to fly as to become boring
and repetitive. With flaperons deployed, 10 ft. square loops are also easy.
However, they never become boring to
fly, especially inverted!

There is no tendency to roll out of any inverted maneuver,
including outside Avalanches (outside loop with a snap roll at the top). Vertical
rolling maneuvers get very vertical, very fast. Avoid letting it get too high
to see because it will if you let it.

Surprisingly, its slow speed flight is another near wonder.
The extra elevator movement allows the airplane to virtually stop in midair.
The TAMEcat EP refuses to stall without power input. In fact, it might be
possible to “Harrier Land” the TAMEcat EP if the landing gear is attached to
protect the propeller during touchdown. Regular landing speed remains on the
slow side, about 15 mph.

Removing the “Y” cord allows flaperon deployment. Deploying
the flaperons does not lower landing speeds by much. However, mixing them with elevator
input like a Control Line Stunt airplane expands the airplane’s performance
envelope to square loops, inverted spins and all sorts of sudden flight
attitude changes that are really fun.

Photo 37

The flaperons also make spot landing easier. This is a very
light airplane with a fairly large wing. Once it enters Ground Effect during landing, this airplane doesn’t want to come
down. It floats forever. The flaperons act as speed brakes to help the airplane
to maintain its descent rate even in Ground Effect.

     

Photo 38      Photo 39

I almost forgot to mention just how great the TAMEcat EP
looks once airborne. It truly looks like a jet fighter. This is especially so
once the motor is shut off in flight. The propeller becomes invisible as it
folds flat against the fuselage. Get up to top speed, shut down the motor and
whistle down the runway. The propeller folds out of sight and you have an F-14
flyby.

When going away, the propeller is invisible and the
airplane’s rear view looks like you should be able to see the afterburners
lighting up the clouds. Very clean!

The TAMEcat EP, despite its being a smaller version of the
TAMEcat 40 basic trainer, is not designed to be a first airplane. The
acceleration is too fast to be a good trainer. While the airplane is gentle and
easy to fly, the pilot must be “further ahead” of the airplane than a good
trainer demands. But as a second airplane, designed to ease the transition from
trainer to complete aerobatic aircraft, I can think of no better airplane than
this one. It looks good, too.

Despite all this maneuvering, the 2100 mAh battery lasts at
least 12 minutes; longer at saner throttle levels. Long flight times,
impressive slow speed performance, vertical at its best and relatively easy to
fly, the TAMEcat EP, at only $100 including the motor, is an airplane worthy of
your hangar. This is the first AirBorne Models airplane I have ever built. I
was so impressed by the quality, prefabrication and the airplane’s performance,
that it will be far from the last.

I mentioned above that this was one very tough airplane. I
can prove it. During a very low, high-speed inverted pass for the camera, I let
the vertical fins touch the ground. The airplane immediately followed this
stupidity by jamming its spinning propeller hard into the dirt, followed by the
remaining parts of the aircraft. The result? One propeller blade broke off its
mount, requiring a new spinner backplate. That was it. An $11 repair (spare
parts are always available for any AirBorne Model’s airplane) and we were back
flying. No airframe damage at all! Even the vertical fins remained locked in
place and did not dent or break.

For more information on this excellent Park Pilot airplane,
go to: http://www.airborne-models.com/html/productdetails.asp?ProductID=119

   

TAMEcat
EP Distributor:

AirBorne
Models
2403
Research Drive
Livermore,
CA 94550
(925) 371-0922
www.airborne-models.com

Spektrum
Radio Distributor:

Horizon
Hobby
4105
Fieldstone Road
Champaign, IL 61822
(217) 352-1913
www.horizonhobby.com

Extreme Flight
RC

3600 North
Pkwy. Suite 101
Atlanta/Cumming, GA 30040
(770) 887-1794
http://www.extremeflightrc.com

Short URL: http://masportaviator.com/?p=931