Product Review - 2004/02

P r o d u c t R e v i e w Frank Granelli
24 Old Middletown Rd., Rockaway NJ 07866
Top Flite R/C Nobler
Pros:
• Complete instruction book
• Strong, light construction
• Laser-cut pieces fit properly.
• Many prefabricated parts
• Excellent flier
• Sleek appearance
Cons:
• Wingtip pieces should be made from
thicker balsa to prevent warping.
• Rudder could be more effective.
Shown are several generations of the R/C Nobler. The fin and stabilizer size differences
are easy to see. Other improvements are subtler.
The Top Flite R/C Nobler’s long nose and rear-set canopy give it that sleek 1930s
racer look, even on the ground. This is a great all-around sport model.
Photos by the author
I AM A DEDICATED, longtime Radio
Control (RC) Nobler lover! My first RC
airplane was a red Nobler purchased in
August 1970. It had that sleek 1930s
fighter/racer look and flew maneuvers I
never knew existed.
However, I wisely put away the red
airplane after one flight attempt, bought a
trainer, learned the basics, and then flew
two other low-wing models. Only then did I
fly the Nobler, and I didn’t stop until the
fuel soaked through the epoxy and the
MonoKote began to crack many years later.
That airplane is still hanging on my wall.
Since 1973 I have flown with one RC
Nobler, and it was scratch-built from a kit I
was lucky enough to find. The original RC
Nobler, converted from the famous George
Aldrich Control Line Nobler, was a model
ahead of its time, with coupled or
independent flaps, a fast roll, a powerful
rudder that allowed knife-edge climbs
(nearly impossible using the engines then
available), a great climb, and pinpoint
flight-path accuracy.
However, the original version was tricky
to handle, stalling easily with a vicious
snap. The no-spar wing structure was weak,
and the model was easily damaged because
the wing was permanently mounted. With
three inches of ground clearance at the
wingtip, dragging a tip made the airplane
explode. The old-design Nobler keeps you
sharp—or else.
My plans were to keep making
templates from that old kit. Then,
amazingly, Top Flite reintroduced my
wonder airplane as a 30th Anniversary Gold
Edition kit (although I don’t understand the
“30th Anniversary” for a design that was 32
years old when the kit was released). I
bought three kits and started building.
Forget any of the original Nobler’s bad
flight characteristics. This new kit is a
modern design, retaining many of the
original airplane’s virtues with none of its
vices. The structure is strong and uses Top
Flite’s well-known Gold Edition
construction.
Start at the Back: The 52-page instruction
book (which includes 167 photos and
drawings) begins with the tail feathers. The
manual provides the kit location for each
piece, making part identification easy. All
tail surfaces are built from balsa strips and
pre-shaped parts, and then they are sheeted
for strength.
Before sheeting, make small gussets
from scrap and glue them into every corner
February 2004 61
02sig2.QXD 11/25/03 1:05 pm Page 61
Open wheel wells can adversely affect performance. Wall them
closed using 1⁄32 balsa coated with thin epoxy and paint.
In the air the R/C Nobler looks as clean and as fast as it is. It’s
stable, predictable, and a fun model!
Clean laser-cut pieces, preformed cowl and wingtips vs. die
“crunch” and balsa blocks. New RC Nobler is more fun to build.
62 MODEL AVIATION
Not Your Father’s Nobler
Top Flite’s new R/C Nobler is not a reissue of the
classic. The new airplane has been aerodynamically
redesigned while retaining the same general outline. The
wing’s outline is the same, but the airfoil is thicker, the
center of lift is farther forward, and the leading edge is
blunter. The new wing provides more total lift, reduces
snapping tendencies, and lowers stall speed while providing
extra stability.
The fin and the stabilizer are 40% larger, providing more
lateral stability and low-speed control. The rudder area is
the same but with a constant chord rather than a 50% chord
increase toward the bottom. The rear fuselage’s side area
and canopy are larger.
The new Nobler feels more positive in the air, and it
penetrates and slows better. It flies the fast, “snappy”
maneuvers like the old design does, but it can fly more
smoothly, performing with extra grace and better
“presentation” (i.e., it’s prettier in the air).
However, the new Nobler’s knife-edge flight is weak,
probably because the constant-chord rudder provides less
force along the fuselage’s lifting side area. The old Nobler
responds to wind gusts by nosing down, and the new
airplane responds by yawing—a better alternative in my
opinion.
The new model is much easier to build and to fly. MA
—Frank Granelli
not braced by stringers. Mark where the plywood control-horn
mounts will be placed, and do not glue these areas when sheeting.
This allows the balsa sheeting to be removed before you install the
plywood mounts. The tail builds quickly.
The fuselage uses Gold Edition construction and laser-cut parts
to ensure perfect alignment. A 3⁄32 balsa crutch (called a top deck)
acts as a fixture. All parts are assembled onto this crutch.
Construction is easy, but there are a few things for which to watch.
As in all kits that use a fuselage doubler, make a right and a left
side. You need to cut the right-side doubler 3⁄32 inch shorter in
front, before gluing it to the side, to provide the required right
thrust. This right thrust is also built into the top deck. When making
the balsa fuselage sides, align both doublers using only the wing
saddle.
Mark the top and bottom former positions on the top deck and
on both fuselage sides. This ensures that the formers will be square
and upright. One of the nice things about the Nobler is that the
fuselage sides are straight and level from the firewall to the rear of
the wing saddle. This makes fuselage alignment, stabilizer and fin
installation, and wing positioning a snap.
It is hard to misalign this fuselage. The sides glue to the
former/top-deck assembly, and the rest is easy. When bracing the
firewall, substitute hardwood triangle stock for the kit’s balsa. This
airplane deserves a powerful engine, and making an extra-strong
firewall structure can’t be a bad thing.
Being able to install the control systems while building is one of
the advantages of a wood kit. Radio installation is simpler and
easier. The book’s photos and instructions cover this in detail.
One change I suggest is to locate the rudder servo next to the
elevator servo at the rear of the wing saddle. The Nobler needs tail
weight anyway, so it makes little sense to position it up front.
Leave enough room between the servos for the flap control rod.
This also eliminates two extra servo rails. Brace the servo rails with
hardwood triangle stock, outside the servo area, at the fuselage
sides.
Delay the topside construction until after you have built the
wing and installed it, the stabilizer, and the fin. You might as well
use those straight sides and top to get everything aligned.
The Noble Heart: As with an airliner, the heart of this airplane is
its wing. Everything happens here, including the flaps, the retracts
(if installed), the powerful ailerons, and an intricate but strong
wing-mounting design.
Before you begin the wing’s construction you have to decide
whether you want retractable or fixed gear. The airplane flies well
either way, but it is a bit more stable in gusts with the gear up. It is
also significantly faster. The directions cover both configurations in
detail. I chose the retract option and used the suggested Great
Planes .40-size system. It costs less than $30 and has proved
reliable in many of my aircraft.
The Gold Edition wing is a strong, I-beam-spar, twin-D-tube
02sig2.QXD 11/25/03 1:05 pm Page 62
February 2004 63
design using a second rear spar as the ribalignment
fixture. Proper rib spacing and
alignment are assured because both spars
are notched for their companion ribs.
Carefully position the spars on the plans,
and the wing has to be straight—a nice
feature.
Another good quality is the clever wing
design that provides the performance
features of a double-tapered wing without
the construction hassle usually associated
with it. The wing’s real trailing edge is
straight, allowing easy construction and
alignment, but the flaps and ailerons taper,
making the completed wing the fastrolling,
precision-flying structure that it is.
As always when building a wooden
wing, weigh the wing ribs and put the
heaviest of each pair on the right side,
opposite the muffler. This reduces the need
for wingtip weight. Do the same later with
the wing sheeting.
The wing builds fairly quickly, seeming
to “fly” together, but you need to pay
special attention to a few details. During
construction use scrap 1⁄16-inch spacers
between W1 and W2 to make sure that
there will be room during wing assembly
for the spar joiners.
If you are installing retracts, you will
notice that the gear-mounting rail has to be
cut nearly through to make room for the
leg spring when retracted. Brace this rail
with another rail epoxied underneath and
to the wing ribs.
The gear itself occupies the entire rail,
leaving the sheeting without an anchor
point after the wheel well is cut out. Glue
scrap capstrip balsa pieces on the outside
of each rail, at the same height, to serve as
the missing anchors. For the same reason,
make two extra W7 and W6 rib bottoms
and glue them to the original ribs outside
the aileron servo hatch. Also put scrap
capstrips front and rear of the servo rails.
The flap servo rails span the entire
center-section and act as an additional
wing brace. Do not yield to the temptation
to shorten the rails to save weight. Make
sure that the flap servo and control rod do
not interfere with the elevator and rudder
servos.
Before gluing the retract servo’s
mounting blocks to the balsa center
sheeting, cover this area with 1⁄32 plywood
and glue the mounting blocks to the
plywood. Otherwise the balsa sheeting
may separate under the servo strain. The
retract servo mounts parallel to the leading
edge with the servo wheel on the side
opposite the throttle servo for clearance.
Epoxy and screw the aileron mounting
blocks to the plywood aileron servo hatch
using #2 screws. This airplane is too much
fun to fly to have to worry about aileron
servos coming loose during Lomcevaks.
Don’t forget to install the aileron extension
wires before covering the wing.
This next step is interesting. Check out
the wing-mounting system in the photo.
The belly pan mounts the wing, determines
the incidence, and strengthens the fuselage.
This unorthodox system is extremely
strong, with all of the mounting plates
braced on all sides. Unlike the traditional
front-dowel/rear-bolt system, this design
firmly ties the front fuselage section to the
rear portion, as if the wing opening never
existed.
Take care to ensure that the fuselage
mounting plates are square and at exactly
the proper depth. Do the same for the wing
plates. For added strength I use balsa
triangle bracing at all corners of the belly
pan. I also use screws and epoxy to attach
the wing’s mounting plates. Seat the wing
and align it as usual in the wing saddle, and
then pin it in place. Build the belly pan on
the mounted wing. Reinforce the wing/pan
joint with an epoxy fillet on the inside of
the pan.
The rest of the wing finishes as usual.
The flaps and ailerons have the same
construction as the tail feathers. Block-sand
the stacked elevators, flaps, and ailerons to
make certain that they are the same size.
Use the CAA hinges provided; they have
proved durable throughout thousands of
flights.
The wingtips are one of the few
problems I encountered. The 1⁄8-inch tips
are too thin, even with the bracing
provided, and they warp when the covering
is applied. Also, both sides of the wingtip
must be the same color because the plastic
film has no place to adhere except to itself.
I suggest making a new tip from 1⁄4
balsa, cutting the lightening holes and
sanding the tip braces to fit. (A secret
among us old Nobler fliers is that the
airplane flies better without wingtips.
However, this is a new design [see sidebar],
so I can’t suggest that you try this
approach—yet.)
Finishing It All: Level the fuselage and
mount the stabilizer and fin, making sure
that both are square and level, but do not
glue the fin in place. Mount the engine
using the marked firewall holes, install the
tank and lines through the handy bottom
hatch, and put in the throttle linkage. After
everything is mounted and the linkages are
checked, glue the fuselage bottom in place,
and then glue in the top formers. Install the
bottom hatch.
The manual instructs you to sheet the
turtledeck and glare panel using wet balsa.
It works for the glare panel, but the
turtledeck has too many compound curves.
Instead I planked it using 1⁄2-inch-wide
strips cut from the provided sheeting. The
resulting turtledeck is strong, light, and
smooth, with no low spots.
Not much sanding is needed to finalshape
this Nobler’s fuselage, unlike the old
one’s. This kit’s heavy plastic cowling
eliminates the drudge sanding that the old
airplane required. When you are ready,
lightly sand with 400 grit, work toward
1,200 in steps, and then cover with your
favorite plastic film. I used MonoKote and
painted the inside of the canopy using
model-car paints, but you can leave it clear.
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02sig2.QXD 11/25/03 1:06 pm Page 63
64 MODEL AVIATION
Engine and Radio: The Great Planes
adjustable engine mount easily fits my Webra
50, which weighs 11 ounces and turns an
APC 11 x 6 propeller near 13,000 rpm on
15% sport fuel. The finished model weighs 5
pounds, 2 ounces—only 4 ounces more than
the older fixed-gear version shown. Any .40
engine would perform well, but, as the
directions ask, why put a small engine in an
aircraft that was so clearly meant to fly?
JR’s trusty XF 652 radio provides the
guidance with plain 517 sport servos for
muscle. I like the 652 in performance
airplanes since it provides rudder/elevator
mixing to remove knife-edge “walking” and
allows the flaps to be coupled with the
elevator and/or be independently lowered.
The 700 mAh battery mounts behind the
wing saddle.
Stretching the Sky: It was a cold, windy
day, but I didn’t care; I was going to fly a
new Nobler for the first time in 10 years. The
engine worked perfectly, everything was
balanced laterally and at the center of gravity,
the radio worked, and the sky brightened as
“Shadow Walker” started rolling over the
runway.
Liftoff was reached before full throttle,
and that got my attention. Doing that with the
old Nobler meant a great deal of rudder to
stop the coming snap roll. This time there
was nothing except a smooth climbout.
During the first climbing turn I noticed extra
yaw stability lacking in the old design. The
airplane just felt more solid and did not need
the usual rudder inputs.
After trimming three clicks down and one
right on the first pass, I turned the Nobler
back at 75% power and pulled up the wheels.
The airplane leapt ahead, and then I went to
100%, accelerating in the climb. This is a fast
model, and I ended the zoom climb as it
became a fast-disappearing dot.
Back down at 200 feet I tested both knife
edges for “walking.” Little elevator trim was
needed, probably because the Nobler was
designed when airframes— not computer
radios—had to compensate for this. There
was no rudder coupling. Coupled flaps made
for 30-foot square loops at low throttle.
The time came to land and to use those
big flaps. I used 40°, dropped the gear, and
there was no pitch change at less than 75%
power. The airplane slowed like it was flying
in syrup, taking a steep approach path.
Because of the wind it was hard to judge
landing speed, but approach and landing
were no faster than they would have been for
a flat-bottomed trainer in the same
conditions. The ground roll was less than 20
feet.
The next takeoff ended in a vertical
rolling climb to 500 feet, fast inverted to
inverted rolls coming back with an inverted
spin turnaround, and a 16-point slow roll
across the bottom. Yup, it’s still a Nobler. I
tried simple 3-D and learned that the flaps
made waterfalls and blenders easy. Snap rolls
can be fast on high rates but slow enough to
be pretty using low rates. Inside or outside
avalanches can be gigantic. The airplane just
plain looks good in the air, especially with
the wheels gone. Low passes can leave you
staring at its sleek form passing by.
Even as a new sport design, it would be hard
to find a better all-around performer than
this. It looks good, flies fast or slow with
great control, and performs a wide range of
complicated maneuvers with effortless grace.
But as an improved return of one of our
sport’s great classics, it’s an opportunity that
is too good to miss. MA
Specifications:
Item number: TOPA0220
Wingspan: 51 inches
Wing area: 550 square inches
Weight: 3.5-5.5 pounds
Wing loading: 14.7-23.0 ounces per square
foot
Fuselage length: 42.4 inches
Engine: Two-stroke .25-.50 or four-stroke
40-52
Radio: Four- to six-channel with five to
seven servos
Distributor:
Great Planes Model Distributors
Box 9021
Champaign IL 61826
(217) 398-6300
www.top-flite.com/airplanes/topa0220.html
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02sig2.QXD 11/25/03 1:06 pm Page 64