Comet Sparky was the second stick and tissue free flight model airplane
that Philip and I built. His first was the Comet
Cadet. The Comet Sparky was (and still is) an excellent flyer.
Rather than carving the balsa propeller blank, I purchased a 9-1/2"
plastic propeller from Peck-Polymers. Four strands of 1/8" tan rubber
was used for power. The flights are very nice, with about 45 seconds
of slow propeller drive and then a minute or more of glide. It has
been adjusted for a shallow climb in a fairly tight circle, and
then a glide in the same direction. The flying areas in the area
were not huge, and we were not taking any chances of having it fly
away. The photograph to the right shows Philip Blattenberger (my
son) holding his Comet Sparky, and Sally Blattenberger (my daughter)
holding her J-5.
Website visitor Graham Mobley built his Sparky off of these
plans and send these two photos.
I took the sheet templates you attached first built an original
Sparky. I already had plans. Next, my son suggested I build
another Sparky big enough to use his electric motor and three
channel receiver. I scaled everything up by 150%. The 3/16 square
balsa used for the fuselage was scaled to 1/8 square (not exactly
1.5:1 but good enough). In order to keep the airfoil true to
Clark-Y, I installed sub ribs between the main ones and used
the same thickness of tissue that is called for on reg. Sparky.
I mounted the batteries just under the trailing edge to maintain
correct CG. I left the horizontal stab the lifting airfoil just
like original Sparky. I cut the stab 2/3 back from the leading
edge and fashioned an elevator. The motor was mounted directly
to the front nose block. Enclosed are pictures taken in Feb
Sometime around November of 2008, I began removing the tissue from
my Sparky because it had become extremely brittle from being stored
in my North Carolina attic for many years. The structure was still
in excellent condition. My motivation for the resurrection was primarily
a desire to try installing a micro radio system for controlling
the rudder. The receiver and coil actuator was removed from an Estes
Sky Ranger mode that was purchased at Radio Shack for $15. The Sky
Ranger has a small electric motor for the propeller, and a fin/rudder
mounted actuator. Since the plan is to keep the the Sparky as rubber
powered, I cut out the motor wiring in order to save weight. A 3.7
V, 350 mAh Li-Po battery came with the system, but is overkill for
powering only the rudder. I will use a 3 V coin cell if possible
to save weight.
possibility of free flight models flying away or into danger has
always kept me from taking them to their extreme performance capabilities.
A dethermalizer setup is a possible alternative, but I like watching
the airplanes gliding down to a smooth landing after a flight. The
role of the rudder control will be primarily for keeping the Sparky
out of danger, not for flying it around like a radio-controlled
airplane. An ideal flight would be one with a fully wound motor,
a nice circling climb-out, and then a graceful glide back to Earth,
without any rudder control being necessary. Once the installation
is complete, I will publish weight and performance information,
along with a YouTube video.
photos show the Sparky while being re-covered. Here you can see
the tissue paper conduit in the rear floor of the fuselage for routing
the rudder actuator wires while protecting them from the rubber
To the left are the airborne components removed from an Estes
Air Ranger that I bought at Radio Shack.
motor/prop assembly has been removed, as has the 350 mAh LiPo battery.
The weight of remaining components is around 0.2 oz.
The photos at the right show the installation of the rudder actuator
coil, the receiver, and the 70 mAh, 23.7 V Li-Po battery. There
is a tiny SPST switch mounted through the windshield, on the left
side of the plane.
maiden flight of the Sparky occurred on June 22, 2009, in a local
Erie elementary schoolyard. All I had on-hand was some 3/16" tan
rubber (original FAI stuff from about 15 years ago), and the four
strands was nowhere near enough power. The original Sparky was powered
by 6 strands of 1/4" tan rubber, and would climb nearly vertical
With 100 or so turns, the Sparky reached an altitude of about
10 feet and make one full circle to the left before landing uneventfully.
The rudder control was barely noticeable, which was expected since
the rudder area is very and control throw are both very small. As
mentioned earlier, the purpose was to provide a means of moving
the craft out of harm's way, not to be able to steer it through
the air in a specific pattern.
removed about 1/16 ounce of weight from the nose (began with 1/4
ounce), wound in 150 turns, and launched again. This time the Sparky
climbed a bit higher, and was airborne long enough to test the rudder
control some more. Cranking in right stick would change the flight
path to nearly straight from its preferred left turn, and cranking
in left stick noticeably tightened the radius to the left. Is seems
clear that with some time trimming and a few strands of 1/4" rubber,
the Sparky will fly as planned.
the left, I'm getting ready to give the Sparky its maiden flight
with its rudder-only radio control setup. Only about 100 turns were
put on the rubber for this flight. A short video of the flight is
I don't remember where I found out about it - probably in Model
Aviation - but the Marion Airfoils, in Ohio, held a mail-in Sparky
contest where contestants made a certain number of flights and mailed
in their flight times. Philip's Sparky took seventh place (out of
30). It was fun, and they sent us a nice certificate (to the right)
and a rather lengthy hand-written letter from the CD (contest director),
Mr. David Narance.
These two photos were taken in Colorado Springs, Colorado, sometime
Please send me an e-mail an I will send them to you at no charge.
I have one JPG file that is 9,770 pixels wide and is 9.3 MB in size,
and the other is 5,000 pixels wide that is 2.9 MB in size. Please
make sure that your e-mail inbox can handle the file prior to writing.
The plans sheet is made up of 12 individual scans meticulously
stitched together in a graphics editor. Total work time was about
4 hours. Note down by the title box is a scale indicator as measured
off the original plans. The larger file is at 300 dpi, which will
create a printed page of around 33 inches, and the smaller file
is about half that. I also scanned the printed balsa parts sheets.
All copyrights (if any) are hereby acknowledged. I do not expect
and will not accept payment - this is purely a humanitarian service
for the modeler who is desperate for plans for this magnificent
airplane. Thanks to Airplanes and Rockets visitor Andy K. for providing
the sub-rudder portion of the plans.
Comet Sparky Plans (sub-rudder
patterns for balsa sheets are available as well. (see Paul D.'s nifty trick for
the patterns to balsa sheets)
NOTE: Although not shown on the plans,
the center of gravity for the Sparky is around 75% back from the
leading edge. This is due to the lifting horizontal stabilizer,
which exerts an aerodynamic downward force on the nose in lieu of
Sparky Parts Sheet #1
Sparky Propeller Blank Dimensions (see
Sparky Parts Sheet #2
Sparky Parts Sheet #3
Click here to read about how to transfer these
printwood templates to your balsa using Avery label sheets.
NOTE: Printed plans can be purchased from
Plans Service. At the time of this writing, the plans cost $8,
and there is a laser-cut parts kit for $18 (+shipping).
Electric Sparky Conversion (February 1, 2009)
Mr. Paul D. wrote to request plans
and printwood patterns. He printed out the plans at 110% to create
this 3-channel R/C electric Sparky. Paul was kind enough to send
some photos of his masterpiece (click on them for larger versions).
These are the details of the radio and propulsion system:
Two, 5 gram Tower Pro servos. Spektrum AR 6100 receiver.
Electrifly 305MA 2 cell lipo. Motor and controller are unknown,
they came out of a T-6 so I know I should have enough power.
Prop will be a 10x4 GWS cut down to 9x4. I wanted the wider blade
for the lower RPM.
Here is his build thread on the
WattFlyer.com website - lots of detailed photos definitely worth
describes a slick method for transferring the printwood patterns
to the balsa sheets that saves a lot of time.
EC 28PS with an ElectriFly 8A ESC. Still too much power. I'm
going to try a smaller motor next.
The plane will go absolutely vertical, at least for a few seconds
before it's too high to see. I got the weight down to just under
7 ounces and it flies and floats well. The extra weight is welcomed,
it penetrates the wind very, very well.
I'm running a two cell 900Mah lipo and it's more than adequate
for 20 minute flights. I land when I get tired, I have not lasted
until it ran out of battery.
If you are planning on flying this on R/C make the rudder larger;
it's barely adequate. If the motor is off, it's not adequate, it
actually needs a little power to turn. I knew this would be nose
heavy so when I built the plane I didn't use the lifting stab.
My plane balances at about 30%. I had to add weight to the rear
of the plane because the elevator wasn't effective enough. With
the tail weight it flies great, I'm having a lot of fun with it.
A lot of people still ask, " what is it", usually followed by where
can I get one. I steer them to your post.
Is This a Cool Landing Photo Or What?
Paul's Sparky in Cruise Mode
Electric Sparky in a Vertical Climb
Paul D.'s Electric Sparky
Here is an old Comet Sparky magazine advertisement that