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Specifications:
- Span: 48 in.
- Area: 578 sq. in.
- Weight: 3.5-4 lb. target, 5 lb. as tested
- Wing Loading: 20 oz./sq.ft.
- Wing Construction: built-up balsa D-tube
- Airfoil: almost symmetrical, 18.5 % thick section
- Fuselage construction: built-up balsa sheet
- Tail Construction: built-up balsa stick
- Power Reqts: .32 to .40 cu. in. glow engine
- Power System Used: Astro Flight 15 geared #615G, 14 cells (two 7 cell
Sanyo RC2000), Rev-Up 11x8 prop
- Power loading: 67 input watts per pound
- Controls: ailerons, elevator, rudder, throttle
- Price: $59.99
- Available From: Great Planes - www.greatplanes.com
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Introduction
The Great Planes Dazzler is what I would describe as a second generation fun-fly type
airplane. When these special-purpose models first showed up, they were primarily built of
thick open structure unsheeted wings, flat stick structure tails, oversize control
surfaces, profile nose sections, and carbon fiber tail booms. The mission at that time was
to rapidly perform wild gyrations at low altitudes while flying slowly, and to compete in
timed events. Although those models and events eventually became very popular, the
airframes were probably too specialized for general sport flying. The Dazzler is sort of a
hybrid between the original fun-fly model and the traditional sport model. It has the
thick wing, the light tail, and oversize control surfaces, but instead has a conventional
fuselage. Also, the entire structure is somewhat more robust than the truly competitive
fun-flyer. The result is a design which features the best of both worlds.
I’ve been flying RC for a long time, so I have a natural inclination toward
converting glow powered models to electric power. As I see it, there are four major
concerns: 1) picking a design that fits your flying style, 2) choosing the proper power
system, 3) determining how to install the electric power components, and 4) saving as much
weight as possible. Obviously some glow powered planes are more adaptable to electric
conversion than others. Frankly, I had some initial reservations about the Dazzler. It is
a style of model that is meant to have a low weight and high power to haul around a rather
high drag configuration. However, the conversion is likely to have greater weight and less
power, and there is nothing we can do to reduce the drag of that fat airfoil. The
challenge is to find a happy medium between expectations and reality.
I think we have a pretty good combination here. I used the Electri-Calc computer
program to sort through some alternative power systems. I chose an Astro Flight sport wind
geared 15 with a 11x8 prop on 14 cells to approximate the power of a glow .32 engine. This
is somewhat beyond the manufacturer’s recommended configuration for the motor, but
within its capability. The airframe is already designed for minimum weight, and I could
not find any place to make a significant improvement. The completed airplane is a pound
over the manufacturer’s target, due to the battery weight. I used two separate 7 cell
packs to work around the wing that goes through the fuselage midsection. The plane
has a large access hatch on the bottom of the fuselage, and I was able to get all the gear
inside, without having to relocate any of the servos. With good throttle management, the
Dazzler can be flown just about like it was intended. It is moderately fast, and very
maneuverable. The Dazzler's flight performance has exceeded all my expectations.
Kit Contents
Kit Contents - clean balsa and light plywood die-cutting; light grade balsa
sheeting; medium grade strip stock; nice hardware assortment.
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The Dazzler kit uses very conventional materials. The ribs and fuselage
sides were on die-cut balsa sheets, 1/16" and 3/23" respectively. The formers
were on a die-cut 1/8" light plywood sheet. All of the die-cutting was clean. The
1/4" aircraft ply firewall looked to be cut on a saw. There was lots of
1/4"x1/2" balsa strip wood for framing the control surfaces plus some
1/4"x3/16" for internal bracing. The wing spar material was 1/4"x1/4"
basswood, the trailing edge was 1/4"x3/8" balsa, and the leading edge balsa
stock was a robust 5/16"x1-3/16". All the balsa strip stock was a nice medium
density, and most pieces were straight. There were several light density 1/16" balsa
sheets for the wing leading and trailing edges and turtledeck.
There was a nice heavy gauge clear canopy, wrapped in tissue. The pre-bent 5/32"
landing gear wire was tucked in so it did not shift around. The included pushrods were
1/16" wire in plastic tubes. The hardware bag contained an ample supply of nuts,
bolts, horns, clevises and such, plus a large strip of flex hinge material. The rolled
plan sheet appeared to be generated on a CAD system. The 20 page instruction booklet was
well organized, with numbered construction steps, and lots of clear photos. I would rate
the overall kit quality very high.
Equipment Planning
Now here’s a step that you don’t see in every kit review, but is part of an
electric power conversion. I started by laying out my system components on the fuselage
side view of the plan. I mounted the geared Astro Flight 15 in a Stitzer Model Design Aero
Vee mount, and placed it where the glow engine would go. I found a good match of thrust
line and motor mount position, even the length was about right. Of course, the flat plate
firewall did make motor positioning pretty easy.
Firewall - only modifications were holes for wire pass-through and cooling air
inlet
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Next I placed a couple of 7 cell battery packs end-to-end from the
firewall to the fuselage midsection. Uh-oh, the wing goes through there. I decided that
the minimum modification would be to remove the bottom leading edge sheet and shave about
a 1/2" from the leading edge spar, but not remove any of the lower spar. Thus there
would be battery clearance right through the fuselage, but not in a perfectly straight
line. With this modification I was satisfied that the two 7 cell packs would fit with
ample room to spare for other components. I also decided to make the bottom hatch more
easily removable by using a tongue at the front and Goldberg hatch latches at the back.
I planned to put the speed control in the fuel tank compartment, and the receiver, its
battery and two servos in the mid compartment. Final locations would be based on achieving
the proper center of gravity. It is common to relocate the servos further aft, so I
planned to leave off the bottom sheet until I knew for sure. Later, I found that I did not
need to move them. I expected to modify the construction sequence a little along the way,
to keep my options open.
Construction
The Dazzler construction approach is pretty conventional. The permanent mounting of the
thick wing through the fuselage is the most obvious departure from the norm. Some of us
will remember this technique from our controlline days. I used the three viscosities of
Great Planes Pro CA glues for all construction except the firewall and wing joiners, where
I used their 30 minute epoxy. The overall construction process moved along rapidly. The
parts fit was very good.
The booklet starts with framing the horizontal and vertical tail sections and the
ailerons, using 1/4"x1/2" and 1/4"x3/16" balsa strip stock. The tail
pieces also use corner gussets. These built-up structures were very light, yet strong and
warp-free.
Wing
The wing panels are next. A section of the plan is to be cut out so the wing tip could
be taped to the main drawing. I don’t like to cut up my plans, so I traced it onto
drawing paper and taped that into position. Even though there is no dihedral in the
finished wing, the panels are built separately and then joined. This very thick wing has a
flat section on the bottom of the airfoil so the wing can be build right on the flat
board. It would be impossible to accidentally install a rib upside-down.
Wing construction starts with the lower 1/4" sq. basswood spar and TE sheet pinned
down over the plan. The ribs are glued into position, followed by the 1/4"x3/8"
balsa TE spar, 1/16x1" balsa sheet sub-LE, and top spar to lock things together. Then
the large 5/16"x1-3/16" balsa LE piece is added, leaving a ledge for the top and
bottom sheet to be added later. The second panel is then built to the same level of
completion. The panels are joined with plywood braces at the LE, TE and main spars, and
with a die-cut light plywood servo tray in place. At this time I left out the servo tray,
since their final position was undetermined.
In the next step, four sheets of 1/16"x3" balsa are to be trimmed to
2-3/8" wide for the leading edge top and bottom sheeting, leaving the remaining
5/8" pieces for rib capstrips. I measured against the wing itself, and noticed that
this only provided for a 1/16" overlap at the spar, about 1/16" short of the
middle of the spar which is shown on the plan. So, I trimmed my sheeting to 2-7/16"
wide, and later cut the capstrips from my own spare sheet. Note that you can’t tell
this by measuring on the plan, because the plan does not take the curvature of the airfoil
into account. The top sheeting and capstrips are glued on, then the wing is flipped over
to do the bottom. Finally the thick rectangular leading edge stock is planed and sanded to
the proper contour. A template is provided.
Fuselage
The fuselage is started by applying some shallow balsa doublers to the side pieces.
These doublers start at the nose and continue a little past the wing opening. Then the
sides are joined together with the four formers. I deviated from the construction sequence
a bit here, by fitting the wing before installing any of the fuselage sheeting or hatch
framing. It was now that I removed the bottom leading edge sheeting and a portion of the
LE within the equipment compartment, and then glued the wing to the fuselage sides. Next,
I continued on with the firewall and hatch installation, but still left the aft bottom
sheeting off until last.
Joining the wing to the fuselage - showing section of leading edge sheet is removed to
allow room for power battery; thick wing is nearly as deep as the fuselage
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Early construction stage - showing wing construction and vertical grain shear webs
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The stabilizer and fin are installed next. Then it is time to fit the
aft top deck sheeting. After a couple of failed attempts to mark the sheet in place, as
shown, I resorted to making a paper template, which works best for me. Due to the slight
compound curve, it was a struggle to get the 1/16" sheeting to lay down evenly over
the formers, and to meet the fuselage sides. Mine ended up a little wavy, and I think that
soft 3/32" would be a better choice here. With the bottom sheeting still off, I was
able to apply glue fillets on the interior of the top sheeting for extra security. I used
Model Magic filler to blend the sheet fillets to the tail surfaces.
I now needed to determine the location of the two servos in the fuselage. I temporarily
assembled all the control surfaces to the model and loaded up all the gear where it fit
best. Then I put the Dazzler on a Great Planes CG Machine, and was relieved to find that
the servos could stay right in the equipment compartment. After this I glued on that
bottom sheeting. I trimmed the light plywood servo tray for just two servos, then relieved
the trailing edge sheeting for clearance, and installed the tray as far aft as possible.
 
Completed but uncovered airframe - note the amount of open framework that saves
weight
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Covering and Finishing
I really liked the color scheme on the box, but did not have the patience to duplicate
it. I stayed with a pattern of lines and angles, and chose bright colors of Top Flite
Monokote, pearl white, teal, and blue. Before covering I cut all the hinge slots with the
new Great Planes Slot Machine. Wow, this was pure magic. You can believe all the rave
reviews. Final sanding of the model was rather easy because of all the large flat
surfaces. Covering was a bit tedious in the area of the wing to fuselage joint, but
otherwise simple enough. What took extra time was splicing the colors together before
applying the covering. I followed the Monokote instructions, and was very successful.
Equipment
I am using a Futaba 6XA radio system, with programmable functions such as flaperons.
The two aileron servos each plug into a separate receiver channel and are coupled as
ailerons and can also be coupled to act as stunt flaps. I plan to try the flaps later,
when I am more used to the already responsive nature of the airplane. All four servos are
the regular size S-3003 model. With such large control surfaces, I don’t think that
mini servos would be sufficient. All control throws were set according to the manual.
Motor installation - Astro Flight 15G is installed on a Sam Stitzer Aero Vee
aluminum mount
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The forward 7 cell 1700 Mah battery pack is held to the nose floor with
a couple of double sided Velcro straps. The aft pack is held to the cockpit floor with the
same arrangement. I have an AI Robotics FX-35D speed control above the battery in the
nose. In the equipment compartment, the 500 Mah flat radio battery is positioned
vertically along side the 7 cell battery. The receiver is placed flat along the power
battery and just in front of the servos. There is some room to shift components to alter
the center of gravity point. A final check on the Great Planes CG Machine indicated that
the Dazzler was balanced right in the center of the range shown on the plan. The final
weight was a fraction of an ounce over 5 pounds.
Nose top compartment - the front 7 cell battery slips into the fuel tank
compartment and slides back to the wing spar; plenty of room for the speed control
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Main equipment belly compartment - servos at the rear just ahead of the training
edge; receiver is shielded in aluminum foil; aft 7 cell battery is underneath the
receiver; radio battery is along side of the power battery.
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My AST-15G turns a Rev Up 11x8 prop at 7,300 RPM and draws about 24
amps. This is a little below the computer prediction, which is fairly common. Initial
testing of the power system showed some interference getting into the receiver. I’ve
seen this before when a receiver is laying up against the motor battery. I wrapped the
receiver in household aluminum foil, and the problem totally cleared up. This may vary
from radio to radio.
Flying
With my chosen power system producing about 67 watts per pound, I was starting to get
quite optimistic about this model's aerobatic capabilities. During takeoff, the Dazzler
accelerates quickly and tracks well, although a little right rudder is needed. The tail
comes up early, and the plane lifts off in about 30 feet with just a touch of up elevator.
Top speed was predicted at 55 MPH, and that feels about right. This is all roughly
equivalent to a glow .32, which is one of Great Planes' recommended sizes. All
flights so far have been from a hard dirt field with scattered clumps of grass.
The Dazzler is quick and agile, but not twitchy with the recommended control throws;
electric power is more than sufficient for spirited flying.
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The Dazzler has a wide speed range too. I was pleasantly surprised at
how slow it would fly, at a high angle of attack with the motor just above idle. I was
even amazed at how far it will glide with the motor off, if the nose is just lowered a
bit. All the while, those big control surfaces provide excellent authority. This makes it
easy to drag it in on the final landing approach and set it down on the spot.
Completed model on paved surface - landing gear easily handles the extra weight
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I feel that the higher of the recommended control throws are still on the conservative
side for this style airplane. The Dazzler will roll quite rapidly, do fairly tight loops,
and good stall turns. It will do continuous rolls or loops until the pilot neutralizes the
controls. All maneuvers are initiated and completed crisply. This requires good pilot
concentration, yet is satisfying because the plane does exactly what it is told. Any
maneuver that can be flown upright can also be flown inverted, with confidence. Now that I
am getting used to the Dazzler, I plan to set the higher of the recommended control throws
on my transmitter low rate and dial in greater throws on high rate.
I am also impressed with the AST 15G motor. It is a good match for this airplane and on
14 cells delivers power in excess of what I would have imagined. The Dazzler's vertical
performance is more than acceptable. I can pull up from fast level flight, and get about
four rolls before leveling off again. And, it doesn't just fall out of this maneuver, it
flys off in the chosen direction.
Recommendation
This has been a very rewarding electric power conversion. It's a quality kit that I
would rate as a good value. The required structural modifications were minimal and the
Dazzler's sport fun-fly design objectives have been preserved. It is a step up in
aerobatic performance from the average electric powered subject. However, it is not too
advanced for an average pilot with sufficient aileron experience. For those of us who also
fly with wet power clubs, the Dazzler should fit right in.
Mar 01, 1999, 01:00 AM
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