In the Northeast, the winter months tend to be long
and cold. After the holiday season is over, the short
and uninspiring grey days can take their toll if you
don't keep yourself occupied. Although we get an occasional
chance to fly off the snow, which is greatly cherished,
the majority of our time is spent toiling away in our
favorite hobby...building airplanes. Before we know
it, our visions that drove us through the long winter
season have taken shape and are ready to test.
springtime finally arrives, my buddies and I are very
excited to get outside to fly our new models and favorites
from the past year. In this month's issue of AMP'D,
we test planes from the last few issues and give tribute
to what we call, the flying season!
Hobby Lobby Executive Jet
The twin ducted fan jet on the right is designed by Super
Flying Model and sold in the U.S. by Hobby
Lobby International. It is made from molded-bead foam
construction, has a 47" wingspan, and meant to fly at
around 47 oz. or 3lbs. The model resembles a Learjet 45XR
with the lower dart fins on the tail. The larger engine pods
are typical on an EDF powered R/C model.
the retracts worked fine, I did not feel that they would work
on grass take-offs and landings. I was proven wrong right
on the first flight. Not only did it take off from grass very
well, it flew very well with no modifications other than the
upgraded power system.
foam planes like the Exec Jet, coating the nose tip, leading
edges, and areas where there are no decals, with finishing
epoxy, helps protect the model from bumps and rash with only
a minimal increase in weight.
Executive Jet looped with ease and performed very well even
in some wind.
power system was upgraded from the stock 3-blade rotors to
the well balanced Wemotec 504 rotors while still using the
stock pre-mounted fan units. Ductedfans.com
sells a nice Dual Rotor Upgrade Kit (WE504ex2)
for this purpose. The Wemotec rotors and adapters allowed
me to use the 3.2mm shaft AMMO 28-35-3900
Brushless Inrunner motors to double my power level over the
stock 2.3mm shaft SFM Outrunner motors. I used the recommended
Thunder Power (TP21003SPL2)
3 Cell 11.1V 2100mAh Lipo Packs for proper balance and long
flights approaching 10 minutes with mixed aerobatics.
SFM Exec Jet flight testing went very well and the video below
shows just how easy it can take off and land on grass. Although
I did not try it, I expect that it can also be hand-launched
without difficulty. Overall, the SFM Executive Jet exceeded
my expectations and proved to be a great start to the 2010
the last AMP'D column, we left off with the "Version
100 Twin EDF Executive Jet from Nitro
Planes ready to fly but without the retracts working.
This is how we tested it on the maiden flight. I figured that
if all went well, I would complete the air line connections
and add the valve servo.
only did the Hero 100 take off with authority, it stayed on
step the entire flight! We tested slow flight, flaps, and
the plane landed, we were all impressed with the flight performance.
It was time to make the retracts work.
the video below, test pilot, Lynn Bowerman, takes the Hero
100 up for its maiden flight without retracts. The flaps worked
well without any pitching, the struts kept the plane from
bouncing on landing, and the navigation lights could still
be seen in the bright sunlight. It was fun to finally see
the PH-LAB airborne.
retract valve and servo were conveniently mounted on the bottom
hatch. Be careful to clear the wing support rods as shown.
I used a pre-enjoyed micro servo that I had for many years.
The regular tiny white "T" connectors and retract
air valve are supplied in the Spring Air 301 retract kit.
following parts were used for an easy hook-up and disconnect.
Note that I simply secured the air intake mechanism with a
few nylon cable ties up front. The stock tiny Spring Air tank
was replaced with a larger Robart tank. When using the newer
Spring Air valves, the air intake is on the center fitting
side. When using the other side that it off center, weird
Robart #169 Pressure Tubing
#172 Small Pressure Tank
#226 Quick Tees
#189 Air Line Restrictors
Cessna Citation II (Hero 100) continued to exceed expectations.
On the second flight, the retracts worked great and the passengers
got a real thrill ride!
was quite windy out but the Citation had plenty of weight
and power to handle the conditions. On the very low pass,
you can see the plane wobble a bit from the ground turbulence.
The Spring Air retracts and Robart main struts performed very
well using the Robart restrictors. The articulated knee nose
gear from Golden Skies R/C does a great job at channeling
the bumps up front. Although I probably didn't need the larger
Robart (small air tank), I prefer having the reserve of multiple
retract cycles available.
few more flights on the Cessna Citation II went very well.
After some quick prep work, the plane took off with plenty
of authority and flew very stable. The retracts and struts
continued to work very well on landings. Flight times were
about 5 minutes with mixed flying and some safety reserve
was at a local R/C show in upstate NY where Team Futaba's
Dan Landis and his dad, Richard, were giving noontime demos
on his giant scale aerobatic planes. When Dan spotted the
PH-LAB Executive Jet, he was already nodding his approval
before I finished asking if he wanted to fly it.
the demo flight, full-scale Gulfstream pilot, Greg Kessel,
performed the commentary as if being on-board with his new
co-pilot that just received his license...in the mail!
Panther fiberglass EDF model was designed after the Grumman
F9F-5 Panther. The Aeronaut model has a 52" wingspan
and weighs about 7-8lbs when flying. It is an all fiberglass
ARF with German-engineered quality which is the best I have
seen to date. It sells with and without retract bays for about
$700 at Icare RC and
the U.S. and at WeMoTec
order to finish my Aeronaut Panther properly, I solicited
the help of my friend, Paul Weigand. Paul applied the decals
with expert precision and created some wing tabs so I could
easily secure them for flight without gluing them permanently
in place. A small screw on the bottom side of the wing not
only secured it for flight but also marked the proper CG.
original release of the Aeronaut Panther in 2003, which is
what I have, did not have landing gear bays or cutouts in
the fuselage. It took off from grass using only 700 watts
on 16-20 NiCd cells. It could cruise around on only 200 watts
in low wind conditions or speed up to over 100mph. The second
release around 2007 had gear bays, cutouts, covers, and a
also created a long battery box using aircraft grade light
plywood. The box allowed me to place the two 4s 4000mAh Blue
LiPo packs end-to-end so that the weight was distributed along
the fuselage and I could easily connect them in series for
a 8s total.
Test Flying the Panther
we were taking the Panther off grass on its belly, we applied
a wide strip of 3M Scotchgard Paint Protection Film on the
bottom of the fuselage and tip tanks. This protection film
is transparent and nearly invisible to the eye. It helps protect
against stone chips, bug damage, abrasion, and weathering.
The 3M Scotchgard Paint Protection Film is available in any
size and length at Empire
power system for the Aeronaut Panther used newer technology
components along with the proven high-quality WemoTec Midi
Pro 90mm ducted fan with its dynamically-balanced rotor. The
ARC 36-75-1 inrunner motor delivers about 2700 watts on an
8-cell LiPo pack in the Midi Pro 90mm fan.
the original power system for the Aeronaut Panther in 2003
was only around 1000 watts. My 2700 watt power system required
some additional work to keep the intake ducts from imploding.
Further, my "new" model had already been stored
for 6 or 7 years in the box so the intake seams may have weakened.
The intake duct lips were sanded and resealed along the opening
rim with a fiberglass cloth coated with V-poxy. This was also
done along the seam that goes lengthwise down to the DF unit.
The V-poxy dries as hard as a rock so my intake ducting seemed
much stronger after this effort.
JRs, Devin McGrath, tested the Panther on it first few flights.
The flight performance was incredible and the glide performance
almost unbelievable! Without any retract openings on the bottom,
the super-clean fuselage seemed to glide forever, making the
Panther difficult to land without proper setup.
the first few flights, we decided that the tail flex of the
horizontal stabilizer was causing pitch changes when the Panther
banked too sharply at high speeds. When banked softer, at
high speeds, it seemed ok. The tail was easily removed with
the single screw and I glued some thin hardwood sticks along
the sides and a third thicker one across the center where
it meets the fuselage. This made the tail much stiffer with
minimal weight gain.
next set of test flights are scheduled for later this summer.
Lander PC-Coated Panther uses a revolutionary new PolyCarbonate
(PC) process that provides a hard 0.3mm shell finish over
foam. It won't dent, break, or shatter. The PC is a lightweight
coating that is lighter than fiberglass and adds durability
to foam never seen before. The smooth glossy finish can be
painted without surface preparation with a result that resembles
a fiberglass model but has a lower cost.
the time of writing this column, we were still experimenting
with the RC Lander Panther. Although it did not have the power
to take off from grass, it could be hand-launched when lightened
by removing the landing gear and using the 4s power system.
We expect that the 6s power system and retracts would work
fine off pavement.
Wan has introduced an upgrade power system for the PC Panther
that utilizes their 76mm EDF. The thrust ratio is now close
to 1:1 and the AUW is only 175g more than before when using
the same 6s 3300mAh batteries. Flight times are still around
3 minutes with full throttle flying.
this flying season, when it comes to executive jets, it's
all about passenger comfort. Although these planes have
plenty of power for aerobatics, it is an awesome feeling
to fly a model scale and suddenly have it look very real.
Cessna 550 DF100 designed by Hero
Models, was only one model in a line of low-cost fiberglass/wood
jets that has introduced many R/Cers to larger EDF power
systems...without breaking the bank! These models were made
in different factories, in Yi Chang and Wuhan China that
were hit hard by the global recession. It is our hope that
we will someday see them return to the hobby market.
smaller EDFs are today's biggest seller, larger sized jets
are available for those enthusiastic modelers with the means.
The Aeronaut F9F Panther was my first high-end EDF that
revealed amazing quality in the assembly, fiberglass, and
finish. Even though it was a smaller mid-sized model, the
level of scale detail required no modifications.
the Northeast, although it is possible to fly during the
winter months, most of our flying is done from May through
September. During these months, we get outside as often
as possible to fly our new models and favorites from the
past year. If your hobby is an obsession, as it is for me,
we mark all the R/C events on the calendar and try to schedule
the rest of our life around the flying season.
you fly electric, fly clean, fly quiet, and fly safe!
thanks for contributions by:
"Papa Jeff" Ring, Paul Weigand, Lynn Bowerman,
and Dan Landis
section of AMP'D covers some of the questions that our
readers have sent in and I thought would be interesting
J. asks: How did your epoxy hold up on the Hawk?
I was afraid of the extra weight and now mine has
lots of dings.
I assume you mean my FlyFly BAe Hawk which was
brushed with BSI 20-minute Finishing Epoxy. My
Hawk is two years old now and was recently flown
in June by Dan Landis. It still looks great and
I think Dan was pleasantly surprised at how well
it really flew.
when you are bored, could you post a few tips
on estimating amp draw for EDFs? I like your thrust
rig but I am wondering if any of the software
packages available for prop/motor combinations
can be used for EDFs?
may be interested in trying the eMotor Calculator
for Ducted Fans called eCalc.
eCalc are software services to calculate, evaluate
and design electric motor driven systems of any
type. This is a free Service for non-commercial
you have to turn it on in your browser.
a great calculator to get you started in the right
direction, but it does not include all of the
component choices that are available today.