The Millennium Falcon
Dennis Weatherly takes a look at this high performance sailplane manufactured by New Creations R/C. The Millennium Falcon is a real sweetheart. If you can handle basic epoxy-glass, wood, and foam construction, you can build this model, and if you are looking for a first high performance electric sailplane, this might just be the plane.
By Dennis Weatherly |
Sep 22, 2002, 01:00 AM
- Span: 84 inches
- Area: 640 sq. inches
- Airfoil: SD7037
- Weight: 64 ounces, as reviewed.
- Wing Loading: 14.4 oz/ sq. ft.
- Power System: Aveox 1412/2Y, 10 x 1700 SCR cells
- Power Loading: 150 watts/lb.
- Number of channels: 3 to 5 (ailerons and flaps are optional)
- Skill Level: Intermediate. Suitable as a first high performance
- Available from: New Creations R/C
Back at the 1996 KRC, between onslaughts at the New Creations R/C booth, Kirk and I
discussed my desire to build an electric-powered sailplane. I didnt want a 7-cell, 2-meter floater, but I couldnt afford an F5B ship either. Kirk recommended his own
Millennium Falcon kit. After a bit more discussion it sounded like a good match, so a deal
The Millennium Falcon is a 7-16 cell electric sailplane. The fuselage is large enough to
accommodate anything from a geared 035 to an FAI40. The Schuemann style wing planform
spans 84 inches and packs 670 square inches of wing area. The airfoil is the SD7037 that
is very popular with the sailplane crowd. The stock kit is a polyhedral, rudder/elevator
model. An insert in the instruction manual provides some input on adding ailerons and/or
The kit box that arrived was pretty substantial in size. Digging through the packing
material revealed a pretty complete kit, including:
- a very nicely molded epoxy-glass fuselage with integral fin, rudder, and T-tail mount.
- white foam wing and stab cores pre-sheeted with obechi (the deluxe kit includes
- the minimal balsa and ply needed to complete the airframe.
- all pushrods and links, many of them already pre-bent to shape with Z-bends at the servo
- construction notes and drawings (there are no full size plans except for the rudder).
Also in the box were a few extra bits that I had added to the order (and which you may
want to purchase also):
- a nice, machined epoxy-glass motor mount.
- an Aeronaut carbon fiber 12x7 folding prop with the proper size spinner and a +5 degree
yoke for added pitch.
Construction begins with the wings and stab. Balsa leading edges and tips are glued in
place, and then carved and sanded to shape. Set the stab aside at this point, resisting the
temptation to cut loose the elevator. The wing has five pieces: a flat center section, tip
panels, and small tiplets. At this point, you need to decide whether you want a 2-channel
polyhedral model or if you intend to add ailerons and/or flaps. If you intend to have
servos in the wings then be sure to make the wire channels in the wing panels before they
are joined. I had told Kirk that I would use ailerons, so he had already drilled out the
wire channels for me. You can do this fairly easily with a long piece of brass tube
mounted in a drill or by heating the end of a long piece of piano wire and melting the
wire channel into the core.
Robbe aileron mounts worked out great. They require a 2-inch hole to be
routed in the foam core, and then the mount is glued in place. Aileron horn was made
from fiberglass PCB material.
Sand in the appropriate angles at each root and tip rib, and then epoxy the
panels together. I chose to modify the recommended dihedral angles to more closely match
models like it in my area. I ended up with five degrees between the center and tip panels
and zero degrees between the tip and tiplet panels. The center-to- tip panel joints are
reinforced with two inch wide glass cloth and epoxy, while the tip-to-tiplet panels get a
3/4 inch wide tape. Once cured and sanded, cut free any control surfaces you intend to use
on the wing and cap the cutouts with balsa or obechi.
If you plan to have a movable rudder then you can dispose of the epoxy-glass one in the
kit and build the balsa version. All of the wood needed was provided in the kit, and was high quality, lightweight stock.
The fuselage needs minimal construction. Thoroughly wash the fuselage to remove any
mold release. Fasten the motor mount to the motor, and then slide this assembly into the
fuselage. Fit a spacer to the back of the spinner (I used thin cardboard stock) and then
mount the spinner on the motor so it is snug against the front of the fuselage. The proper
down and right thrust is already molded into the nose. When satisfied with the fit, tack
glue the motor mount into place with 5-minute epoxy. Then remove the motor and spinner and
build up a solid glue joint around the mount. I used 30-minute epoxy with milled
fiberglass fibers added to increase the strength.
All thats left on the fuselage is to epoxy in the wing bolt plate and build the
rudderpost. This was my first model with the servos mounted in the fin, but the
instructions were quite clear about how to proceed. Just be sure to run the servo
extensions and tape the connectors before you glue the rudderpost/servo mount assembly
into place! For the aileron servos I used the Robbe aileron servo mounts that Kirk
recommended. These require a 2-inch hole to be routed in the wing. I glued the mounts into
place with polyurethane glue. The servo drops into two rails and is secured by the mount
cover, which also has an integral pushrod fairing. Very clean!
The next steps cover fitting the wing and stab. The wing saddle on my model required
some careful grinding with a Dremel before the wing would fully seat in the saddle, but
the final fit is quite good. A single 1/4-20 nylon bolt holds the wing trailing edge in
place. I added a small half circle of 1/16 plywood here to spread the loads out over
the obechi skin. The front of the wing is held down by the fairing on the fuselage. A hard
1/4 inch square balsa stick is trimmed to fit snugly between the fuselage sides near the
wing leading edge and then glued to the wing to keep if from shifting side-to-side. I was
uncomfortable about this, but left it alone.
Once the wing is mounted you can fit the stabilizer. It is bolted to the top of the fin
with 6-32 metal screws. I had to trim the saddle a bit from side-to-side to get the wing
and stab parallel. The plans call for one degree of negative incidence in the stab, but my
stab mount had two degrees. I went with this anyway rather than carving up the stab mount. I
had a heck of a time using my Robart incidence meter on the stab because I had already cut
the elevator loose. If you wait to do this until after the stab is mounted then the
incidence meter is much easier and more accurate to use.
After mounting the stab you can finish up the pushrods at the stab and fin. The
fuselage seam required very minimal filling and sanding and then it was time for painting
I elected to paint my model to try to keep the weight down and to allow me to be
creative on the color scheme. The fuselage was shot with one coat of Krylon primer, and then
sanded smooth. I hated this primer! It clogged up the sandpaper very badly, requiring
almost three full sheets of 220 grit wet-or-dry (used dry) to finish the job. On the other
hand, the white, yellow, red and black Krylon enamel went on just fine from the spray can
and glossed nicely.
For the obechi covered parts, I applied three light coats of Flecto Diamond Finish
water-based Varathane. This stuff is nearly odorless, nearly non-toxic and fills quite
well. It does tend to run easily so you have to be careful when brushing it on. Disposable
foam brushes seemed to work best. I sanded each coat lightly before applying the next.
After the third coat had dried overnight I sprayed the yellow, red and black trim with
Krylon enamel and it adhered well to the varathane underneath.
Inside the fuselage, showing the 10-cell 1700SCRC pack, Aveox controller
and the barely visible Hitec receiver. Not seen here is the 600 mAh battery mounted
above the motor controller and inside the wing fairing. There is a lot of room in
here as all the servos are mounted elsewhere!
Since all of the servos are mounted during construction there is very little left to do
at this point. I mounted a 7-channel Hitec receiver way back in the radio compartment,
underneath the wing trailing edge. The direct drive Aveox 1412/2Y and controller had their
wires shortened severely and soldered together to eliminate a potential failure point. I
was expecting in excess of 60 amps current draw, so I didnt want to take any
chances! A 600 mAh NiCD radio battery is Velcro mounted to the wing fairing, just ahead of
the wing leading edge and above the motor controller. The 10-cell 1700SCRC pack just
barely fits between the motor and the receiver, with the motor controller sitting on top
of the motor battery. All of this stacking was necessary to get the CG at the proper
point, in part due to the strong, but slightly heavy pair of Hitec HS-85 servos I had
mounted in the fin.
The wing center section showing the hard 1/4" square balsa stick that
centers the wing leading edge between the fuselage sides. Fiberglass patch around
the aileron wires is to reduce splitting of the thin obechi. Also visible is the
minor damage to the wing leading edge caused by the first hard landing. Note that
this is a good spot to put your name and address (which we've digitally scrubbed from this
photo - ed).
The business end, showing the Aeronaut 12x7 carbon fiber folding prop, +5
yoke and 40 mm spinner. The whole assembly was perfectly balanced from the factory.
Ready to fly weight came in at 64 ounces, or 4 pounds. I was a bit
disappointed in this, as the plans suggest a finished weight around 55 ounces. Maybe my
paint job wasnt so light after all! The plans called out the rudder and elevator
throws, but neglected to mention aileron throws, so I set them to where they looked
"about right", about 3/8" each way. I used the computer in my Airtronics
Module transmitter to set up 50% differential on the ailerons, 50% rudder to aileron
mixing and spoilerons (both ailerons go up) for landing. I could not get the side slider
to operate the motor controller properly, so I ended up putting the motor on the landing
gear switch. Motor tests showed 68 amps current draw at 8700 rpm.
|The completed airplane
Test flight day dawned clear and full of thermals. It was also the local sailplane
clubs summer picnic and fun fly, so I had a crowd around to witness the first
flight. A range check showed plenty of range, with the motor on or off. With the motor run
by the gear switch, I would have to throw the model left-handed. I elected to have someone
else do the throwing on the first flight. I held my breath, nodded to the launcher, hit
the motor switch, and off it went.
Wow! I had never flown a sailplane like this before. I was expecting a good climb, but
what I got was far beyond my expectations. The nose wanted to pitch up under power so I
had to hold a bit of down elevator with the power on. In five or six seconds, it was at
winch launch height. At eight seconds, I shut the motor off and settled the model into a
glide. Handling was really good, although a little more aileron differential would be
nice. Thermal turns are easy to maintain and the model is very stable. It stays where you
put it in a thermal and just flies around and around. It also loops and rolls nicely.
I tested the spoilerons at altitude and was surprised to see the nose pitch UP when I
deployed them. I tried to keep this in mind when landing, but the first arrival was a bit
"firm". No damage to the model, except that the wing leading edge under the
fuselage fairing was beat up a bit. I may replace this section of LE with spruce or
basswood for a bit more strength.
I dialed in some down elevator trim under power and when the spoilerons are raised,
recharged the pack after it cooled and launched again. I threw it myself this time, with
my left hand. I didnt have to worry about getting the model up to flying speed - it
leapt out of my hand as soon as I hit the power switch. The climb is nearly hands off now.
I shut the motor down after five seconds and went thermal hunting. Two climbs and twenty
five minutes later I landed due to tired eyes. On the third flight, I handed the
transmitter around to some local hot-shoe thermal pilots. Everyone was impressed with the
ship. We eventually made six climbs to altitude on this one charge and still had a bit of
power left over.
The Millennium Falcon is a real sweetheart. If you can handle basic epoxy-glass and
wood/foam construction, you can build this model. If you are looking for a first high
performance electric sailplane then I can highly recommend this one.