an R/C plane off water can be one of the best experiences
you can enjoy in our hobby. When done correctly, the site
of your plane gliding across the water is both mesmerizing
and a great deal of fun!
you live in a northern climate, the floats can also be used
to fly off snow. Further, when enough power is available,
a float plane can even take off from grass.
this month's issue of AMP'D, we'll cover some of the key points
in adding floats to any plane as well as some tips on successful
flying off water, snow, and even grass!
Mentor is a replacement for the Magister and is a robust
trainer and tug (tow plane) made of ELAPOR (pronounced el-a-pore)
foam. Medium CA glue used with an activator (or kicker) as
the only method of gluing recommended by the manufacturer.
This radio controlled model is electric powered and Almost-Ready-to-Fly
(ARF). It is meant for beginners to intermediate fliers.
have been around since the very beginning of model flying.
The so-called .40-size trainer was offered in a multitude
of variations all over the world. The beginner is expected
from the outset with an easily damaged all-wood model and
a motor which is not properly set up or even broken in. It
was no surprise that this type of "first model"
was often the modeler's last.
Multiplex Mentor was designed with the beginner in mind. The
ELAPOR foam provides a robust, high-strength structure that
is easily and quickly assembled using CA glue. The aircraft's
flying characteristics are simply outstanding! When using
the mating Multiplex Brushless Motor Power Pack (M993228),
which contains a motor, ESC, Prop, and hardware, the trainer
provides reliable, maintenance-free power flight after flight.
Schwimmer-Bausatz for Mentor
whole new level of fun was created for this model by using
Float Set (or Schwimmer-Bausatz) from Multiplex. The solid
Elapor floats come with custom bent aluminum undercarriage
supports, water rudder, and all the hardware. The 5-language
manual has detailed text and drawings to make the assembly
quick and easy.
first drilling 1.5mm holes in the plastic bars, they are glued
into the mating float slots. I used CA on the float foam,
sprayed the plastic with kicker, and then simply pressed them
undercarriage supports are then mounted to the floats using
the supplied screws. Both aluminum supports angle toward the
existing ground gear undercarriage is unscrewed and the new
float front undercarriage fits right in its place. You can
then mark the exact spot to cut a 6mm deep flat area for the
new rear undercarriage. I used a hobby saw and then lightly
sanded the area flat.
plastic plate is CA'ed in place and the new float assembly
is secured by the four original machine screws up front and
four new sheet metal screws in back. I needed to open the
holes slightly larger in the back brace to allow the sheet
metal screws to freely fit through the holes before being
secured into the plastic plate.
next step is to attach the water rudder. On smaller planes,
I sometimes skip this step and see if the rudder has sufficient
authority to turn the plane in water at low speed. However,
Multiplex states that the water rudder on the Mentor is absolutely
essential for both steering in water and flying. The additional
area of the water rudder is needed to aid the normal rudder
in controlling the larger lateral area distribution. The water
rudder also works in snow!
water rudder is made by copying the full size diagram in the
manual and then simply replacing the steerable tailwheel.
The tail assembly piece must be drilled out to 2mm to accept
the larger metal rod used by the water rudder. I used shipping
tape to secure the foam rudder to the bent rod.
made a few simple modifications to help keep the ESC safe
from water damage. I first sealed the ESC ends with some Zap-A-Dap-A-Goo
II which helps keep the water out.
then cut a piece of nylon screen material from an old furnace
filter and glued it over the air intake opening using more
of the Zap-A-Dap-A-Goo II. This protects the opening from
water splashing inside while allowing most of the air flow
to continue cooling the motor, ESC, and battery.
finished, the CG was in the same spot as before I started
and the float step was right under the CG. Now that's German
Float Flying in the Finger Lakes
Finger Lakes are a pattern of lakes in the west-central section
of Upstate New York. The lakes are linear in shape, each lake
oriented on a north-south axis. The largest lakes in the group
collectively reminded early map-makers of the fingers of a
of our local club events, sponsored by the Canandaigua Sky
Chiefs, is held at beautiful Honeoye Lake in the Finger
in 2003, I did a review of the Bohemia
Models Monocoupe for Hobby Lobby. This 7?, 10lb giant
scale plane was a blast to fly during the summer.
giant scale Bohemia Models Monocoupe has an 82? wingspan
and weighs about 10lbs when converted to electric power. For
all its intimidating size, the 1920s Velie Monocoupe model
was a relaxing docile flyer.
missed flying the model during the long winter months in upstate
NY so I decided to add some floats the following year and
have some fun in the snow! By adding a set of 35? ?Zeedoo?
fiberglass floats, I was now able to fly it all year off of
snow and water.
general rule of thumb is to use floats that are about 75%
to 80% the length of the fuselage. The pre-fabricated ?Zeedoo?
fiberglass floats from Hobby Lobby came in various sizes and
the largest 39? set provided about a 74% ratio which
was just about perfect.
the floats added about 1.5lbs more to my flying weight, the
stock Monocoupe wheels were also removed to drop the weight
by 11oz. My net weight gain was about ¾ lb.
Zeedoo floats were very strong and easy to install. I used
the stock Monocoupe gear axle for the front struts and hand-made
a rear strut from K&S 0.156 (5/32)
music wire. The rear strut was then attached to the solid
brace just behind the cockpit area and reinforced internally.
I used Dubro (#158)
Steel Landing Gear Straps to attach the music wire to the
worked very well and we had a blast flying the big model off
a snow-covered field. It was fun to get outside in the wintertime
and enjoy a sunny day while dreaming of warmer weather. After
the flight was over, I realized that my floats were not very
parallel so I removed one of the front spacers on each side
to make them perfect.
not needed for snow take-offs, a water-rudder is needed for
taking off the water. I selected two of the Ernst (#156)
Retractable Float Rudders for .90-1/4 Scale from Tower Hobbies.
I decided to use two water rudders controlled by flexible
cables from Great Planes (GPMQ3702).
Monocoupe on floats was a good success at a 2004 float fly
in the finger lakes of upstate NY. Although take-offs were
a bit weak, we flew the Monocoupe five times during the day.
airborne, the plane still flew at half throttle but initially
breaking the suction of the water contact required some skill
and long take-offs. After upgrading the power system to an
AXI 4130/16 and a 6s LiPo pack, the Monocoupe was stored in
my garage loft for 6 years.
Return of the Monocoupe
forward to September 2010 and my old Monocoupe was pulled
down from the loft and made ready to return to Honeoye Lake.
testing all the control surfaces, my only real change was
to upgrade the cylinder heads on my mock Velie engine and
change out the old NiMH packs for newer Lithium technology.
original power system for my 2003 review used an AXI 4120/14
with a 14-cell, 2600mAh NiMH pack and APC 13x8 e-prop. I measured
8200 RPMs at 43amps but had no wattage readings. Although
never tested, I had upgraded the power system to use an AXI
4130/16, APC 15x8 prop, with two of the ThunderPower 3s2p,
4200mAh packs in series. The short ThunderPower packs fit
well just inside the nose. The power system drew about 50amps
for 1000 watts of power. The extra weight in the short nose
helped with the balance and I was certain that the increased
power would provide water take-offs in any conditions.
the video below, Lynn took the sticks and showed just how
well the new power system worked when flying off water. The
model flies for about 10-12 minutes on a 6-cell 4AH LiPo pack.
2006, I reviewed the E-flite J3
Cub 25 when it was first released. The review included
the original build with wheels and the optional adaptation
to the 25-Size Fiberglass ARF Floats (EFLA500).
Four years later, the E-flite J3 Cub 25 (EFL4000)
is still being sold, which speaks for its scale appearance
solidly-built model is the only 25-size Cub with scale ailerons.
Quality balsa and light plywood construction make for a sturdy,
lightweight airframe that handles incredibly well in most
flying situations. The firewall is set up for use with an
outrunner motor, such as E-flite?s Power
25, making a perfect power match for the airframe. The
optional floats add a new dimension to the scale flying experience,
and the one-piece wing allows for easy transportation to and
from virtually any flying field, pond or lake.
have found that the E-flite J3 Cub when equipped with floats
takes off well from water, snow, and even grass! It is a versatile
all-seasons scale flyer.
float kit provides a ventral fin for adding stability in flight,
especially at slower speeds.
taking off grass, the floats can be made extra slippery by
spraying Pledge furniture polish on the bottom. While it is
not always needed, keeping a can of Pledge in your flight
box can come in handy when the grass is long and green.
I fly off grass, snow, and water, these HobbyZone Super Cub
seemed like a good experiment to try on my ParkZone Extra
landing the Extra 300 in the thick grass, I would sometimes
rip off the gear mains. Although it was an easy CA repair,
I had other planes on floats that are fun to fly off grass
so it seemed natural to me...but probably not scale.
tested, my Extra 300 continued to perform well on the HobbyZone
Super Cub floats. It retained all its aerobatic capability
while allowing me to take off from grass, water, or snow.
only trick to mounting the floats is to make them parallel
with the plane body so you need to keep the front metal bars
flush with the fuselage bottom. I did this by gluing some
plywood pieces in the existing grooves where the normal gear
mains mounted. You can then hold the front frame in place
either by wedging a center plywood piece in the middle or
gluing it in place.
the back frame, simply cut out a rectangular piece in the
foam so that the additional plastic piece that comes with
the HobbyZone floats mounts flush.
video below is of my stock ParkZone Extra 300 on the HobbyZone
Super Cub floats. As you can see, it has retained all of its
aerobatic capability but the floats allow me to take-off and
land on grass without tearing out the mains.
there are some things to keep in mind when flying off water,
float flying is very similar to flying off land. The length
of the floats should be around 3/4 of the fuselage length
measured from the prop to the rudder hinge.
30" fiberglass floats on the left are sold by Hobby Lobby
for 5lb to 7lb planes. They are similar to the ones I used
on my Monocoupe, only smaller in size. Fiberglass floats have
an advantage over plastic molded
because the corners are molded much sharper, which makes them
plane on the water much better than the rounder-shaped plastic
step of the float should be located on the CG or just behind
the CG. As the plane starts to increase speed on take-off,
the floats ride up onto the step and reduce most of the of
suction from the water surface.
ventral fin, like the one supplied in the E-flite 25-Size
Fiberglass ARF Floats (EFLA500),
will increase the effect of the tail feathers and keep the
plane going in a straight line.
wind picked up in the afternoon so we decided not to fly
the smaller planes like the Clever Boy from Maxford USA
and the Polaris from ModelAero.
You can see a video of the Clever Boy on floats from my
on RCU. Both of these planes can take off from almost any
surface. They are versatile and fun to fly!
of the key points when adding floats to any plane is that
it is not just for flying off water. If you live in a northern
climate, the floats can also be used to fly off snow. Further,
when enough power is available, a float plane can even take
off from grass. If the grass conditions are "sticky",
the floats can be made extra slippery by spraying Pledge
furniture polish on the bottom.
the size of the floats doesn't have to be perfect, a general
rule of thumb is to use floats that are about 75% to 80%
the length of the fuselage. When flying off water, adding
a water rudder and ventral fin help control the plane in
the lake and in the air, respectively.
you fly electric, fly clean, fly quiet, and fly safe!
thanks for contributions by:
"Papa Jeff" Ring, Lynn Bowerman, and Devin McGrath
section of AMP'D covers some of the questions that our
readers have sent in and I thought would be interesting
I read with interest your review
of the T-34 Mentor by E-flite. I have one and
it performs great except that the canopy/hatch
would fly off during flight. At first I thought
the magnets were not engaged but after ensuring
the magnets were ok it flew off again. You can
imagine what losing the hatch does to the flight
others have had the same problem. Horizon did
not acknowledge that there was a problem, but
they did send me another canopy/hatch that unfortunately
did not fit (too long). I have patched the original
canopy with R-560 and I am securing the hatch
with tape to keep it intact. Of course this has
to be removed to change batteries. This is not
a big deal but I am trying to find the real cause
to the mastery of the "flying canopy".
feedback on this problem and solutions? Any ideas
on what might be the cause? I have a suspicion
that it may be air pressure pushing the canopy/hatch
loose. Your thoughts would be appreciated.
agree that the Mentor has a big canopy that you
don't want to lose in flight. It is certainly
possible for air flow to come in from the cowl
front and build pressure inside the fuselage.
This air flow is designed to cool the components
inside. The question is there sufficient pressure
to pop off the canopy in flight? One way to reduce
the pressure is to make the air exit opening about
3 times the size of the air intake opening. There
is some covering on the aft end of the fuselage
bottom that you could cut away to allow more air
to exit?thus reduce pressure
possibility is that the fuselage twists in flight
and weakens the hold of the magnets. A combination
of twisting and air pressure is yet another possibility.
My canopy seemed to hold on well until we really
beat on the plane during aerobatics. A few small
pieces of tape worked nicely to hold it in place.