The box contains an instruction manual, several sheets of laser-cut balsa,
three 1/8" carbon fiber tubes, a pair of hardwood servo rails and a pair of
micro control horns.
There is no plan, but the instructions are photo illustrated. The
photos in the manual appeared to be multi-generation copies and in some cases it
was difficult to figure out what was going on. In general, the
instructions could be significantly improved.
In addition to the photos, some things are not adequately addressed.
For example, the kit is designed for a Speed 280 to Speed 400 power system but
other than telling you where it goes, the instructions only indicate that the
prototype had the engine strapped on with zip ties. Had I wanted to use
e-power for mine, I would have had no idea what to do.
Although the basic airframe can be built in one day, it would take a
considerable effort to have the plane ready-to-fly in one day. The basic
airframe notches together quickly, but then there is a lot of fiddling around
with the usual things.
Before I could start building there were several things I needed to resolve.
As I already mentioned, I converted mine to .061 (1/2A) power. I cut out two
identical 1/16" plywood plates make up the engine mount. One of the plates
took the place of the balsa doubler under the wing and the other went on the top
of the wing. I set up the engine to have about 3°
A good part of the time I spent before beginning assembly was fiddling around
with bottles to use as a fuel tank. Initially I tried a Kodak Advantix
film canister, but I did not trust it not to leak. Eventually I made a tank
from a small bottle I purchased to use as a glue bottle.
The cap is drilled slightly smaller than a fuel tube. The feed line is
pulled through this hole. On the top side of the bottle is the pressure
line. It is also simply pushed into the hole and extends into the tank
about 1/16". This arrangement has
worked fine so far.
In addition to making the tank, I had to figure out how to mount it.
Originally I was going to place it inside the structure and just cut away the
sheeting as necessary to clear the front of the tank. However, if there
were any problems with the tank that would require its removal, then I would
have had to cut into the model to get at it.
Instead, I simply built an open compartment by cutting some sheets to close
off the structure while leaving the tank entirely accessible. The tank is
retained with strategically placed drops of silicone sealant.
I did not have any fuel-proof black paint, so I used Humbrol enamel around the
engine and fuel tank areas and then over-coated them with clear polyurethane.
I really like the way the
parts are designed to lock together. Because a laser cuts at an angle and there
is really no way to sand the dovetails and maintain the fit, one side of
multi-part components has a slight, but not objectionable, gap. The ease and
accuracy of assembly makes most of the assembly idiot-proof.
One thing that I really did not like about the design is that the center ribs
are the correct height without the sheeting that sits on top of them. What
that means is that the covering will be completely suspended until it can be
ironed down to the spar at some point out from the center section.
I think the model would be
better if there were rib doublers for the inside of the center ribs. The
sheeting would sit on the doublers and inside the main ribs. The doublers would
be 1/16” below the main rib so that the sheeting is flush with the ribs. That
would make the outside of those ribs look neater as well as resolve the higher
center section issue.
I added balsa filler pieces to fair the
spar from the center rib to the second rib so that I would have something a little
better to adhere the covering to. It also provides a landing to terminate
the covering so that I could do the scheme that I chose.
If the underside of the fuselage is built according the
instructions, there will be a large opening at the front of the airplane.
I am not sure what that is about because it is not mentioned one way or the other.
I can only assume that it is a typo or possibly for cooling the motor batteries.
However, because the opening is like a shark's mouth at the front of the
airplane, it seems like it would be susceptible to damage on landing.
A set of plans — even 1/2 size would have been nice to
clear some of these things up. I simply sheeted all the way to the nose
and did not worry about it.
The airframe has carbon fiber tube leading edges that I epoxied on to the
balsa leading edge pieces. The balsa pieces would have been strong enough
on their own, so I have no idea what the purpose of the carbon tubes is.
Possibly to strengthen the leading edge on landing as the plane has no gear.
The instructions call for a pair of Hitec HS-55 servos for the elevons.
I do not have any of this model servo, but I do have HS-50's that are
significantly lower in torque and slightly smaller (according to the specs on
the Hitec website).
If you follow the
instructions and use the indicated servos, then there will be a problem with the
servo leads coming through the bottom sheeting and hanging in the breeze.
The photo on the box cover shows the servos mounted farther forward which is
how I mounted the Futaba S3106 micro servos that I chose
for the elevons.
Instead of using the hardwood rails which would have
made it very difficult to insert and remove the servos due to the grommet around
the servo leads, I used two pieces of 1/16" plywood that are flush with the top
sheeting instead. The rails are backed with 1/4" square pieces of the same
plywood to give the screws something more to bite into.
Again, it was hard to tell what was going on in some of
the photos, but it looks like the instructions have you leaving the servo area
unsheeted across the wing. if that is the case, then the included rails
could be used by cutting a notch in them and sliding the servos over to the
notched area to remove them.
Personally, I do not like openings in my airplanes because
they screw up the aerodynamics. Additionally, exhaust from the engine
likes to go in those places and never come out again. The latter, of
course, would not be an issue with E-power. I filled the area between the
servos with some scrap sheet.
This is the first R/C airplane that I have glued my radio in. There
simply was not room for foam around the receiver I used. There are
several smaller receivers available, however. I used silicone to
attach the receiver, battery and throttle servo.
The other thing I needed to figure out was the receiver antenna. I
do not have any base-loaded antennas and really did not want to buy one, so I
tossed the idea around for a bit and finally installed a piece of .020 music
wire permanently in the airframe. The antenna was cut from the receiver
leaving just a piece about 5" long. Together with the music wire, the
antenna is the original length.
The antenna has a small bend to secure it in one wing tip and then runs
parallel to the trailing edge. Before reaching the opposite wing tip,
it loops forward and enters the center of the wing where it is attached to
the receiver. This arrangement range checked fine so I left it
The first day at the field, the radio went berserk when
the engine was running. We discovered that unplugging the antenna made the
problem go away. We do not really know what the problem is, but a
couple things were happening.
First, the #2 wood screws holding the engine to the mount vibrated loose
causing the fuel to become nothing but foam. That is a lot of vibration.
Second, the antenna wire contacts the rear carbon fiber spar which may be
causing some type of problem as well.
In any case, I put the original antenna back on and just let it hang out
the rear of the aircraft. It is not pretty, but it works.