RCU Review: Greg Covey's Amp'd Issue 19: Float Flying

More On This Product

  • Research Airplanes
  • Research Boats
  • Research Cars
  • Research Helicopters
  • Research Engines & Motors
  • Research Radio Equipment
    Contributed by: Greg Covey | Published: January 2011 | Views: 33196 | email icon Email this Article | PDFpdf icon




    Back Issues:

    Issue #18

    Issue #17

    Issue #16

    Issue #15

    Issue #14

    Issue #13

    Issue #12

    Issue #11

    Issue #10

    Issue #9

    Issue #8

    Issue #7

    Issue #6

    Issue #5

    Issue #4

    Issue #3

    Issue #2

    Issue #1


    Issue 19
    Article By Greg Covey

    Print Issue 19 "Float Flying"

    Flying 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!

    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.

    In 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!

    Multiplex Mentor

    The Multiplex 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.

    Trainers 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 to

    cope 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.

    The 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

    A whole new level of fun was created for this model by using the Mentor 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.

    After 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 in place.

    The undercarriage supports are then mounted to the floats using the supplied screws. Both aluminum supports angle toward the float center.

    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.

    The 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.

    The 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!

    The 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.

    I 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.

    I 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.

    When 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 engineering!

    Float Flying in the Finger Lakes

    The 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 hand.

    One of our local club events, sponsored by the Canandaigua Sky Chiefs, is held at beautiful Honeoye Lake in the Finger Lake Region.

    Honeoye Float Fly Introduction Video

    Download and Watch in Windows Media Player here

    In the video below, my friend Lynn Bowerman and I, took turns with the sticks and had some aerobatic fun with the Mentor. This model flies very well for 10-15 minutes on only a 3-cell LiPo pack.

    Multiplex Mentor on floats Video

    Download and Watch in Windows Media Player here

    The Monocoupe on Floats

    Back 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.

    The 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.

    I 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.

    A 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.


    Although 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.

    The 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 fuselage.

    Everything 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.

    Although 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).

    My 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.

    Once 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

    Flash forward to September 2010 and my old Monocoupe was pulled down from the loft and made ready to return to Honeoye Lake.

    After 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.

    The 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.

    In 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.

    The Monocoupe on floats Video

    Download and Watch in Windows Media Player here

    E-flite J3 Cub on Floats

    In 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 and performance.

    The 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.

    I 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.


    The float kit provides a ventral fin for adding stability in flight, especially at slower speeds.

    When 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.



    E-flite J3 Cub 25 on floats Video

    Download and Watch in Windows Media Player here


    ParkZone Meets HobbyZone

    Since I fly off grass, snow, and water, these HobbyZone Super Cub floats (HBZ7390) seemed like a good experiment to try on my ParkZone Extra 300 (PKZ5180).

    When 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.

    When 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.

    The 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.

    For 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.

    The 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.

    ParkZone Extra 300 on HobbyZone floats Video

    Download and Watch in Windows Media Player here


    Float Tips

    Although 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.

    The 30" fiberglass floats on the left are sold by Hobby Lobby (HC1802) 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

    floats because the corners are molded much sharper, which makes them plane on the water much better than the rounder-shaped plastic floats.

    The 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.

    A 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.

    For completes details on float selection and setup, read "THE BASICS OF FLOAT FLYING" by Ironsides and Jim Casey's "RC Seaplane Webpage".



    The 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 2007 review on RCU. Both of these planes can take off from almost any surface. They are versatile and fun to fly!

    One 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.

    Although 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.

    When you fly electric, fly clean, fly quiet, and fly safe!


    Special thanks for contributions by:
    "Papa Jeff" Ring, Lynn Bowerman, and Devin McGrath


    This section of AMP'D covers some of the questions that our readers have sent in and I thought would be interesting for others.

    John W. asks:


    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 characteristics!

    Several 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".

    Any 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.

    Hi John,

    I 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

    Another 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.

    Good luck with your T-34 Mentor!

    Ask questions by e-mailing me at greg@rcuniverse.com


    Hobbico LiFe Source Receiver Packs

    Xoar Beechwood Props

    Spektrum AR6400LBL DSM2 6Ch Ultra Micro Receiver
    with Brushless ESC

    RC Lander Metal Retracts with Suspension Struts


    Print Issue 19 "Float Flying"

    Comments on RCU Review: Greg Covey's Amp'd Issue 19: Float Flying

    There are no comments

    Tower HobbiesJ-3 CubWith its distinctive looks, it is probably safe to say that the J-3 Cub is one of the most recognized and known airplanes in ...11/23/2015
    RCGF21cc Twin Cylinder Gasoline EngineRCGF, a Chinese manufacturer of gasoline engines, designs and manufactures engines specifically for 'the RC aircraft market. ...11/23/2015
    RCGF120cc Twin Cylinder Gasoline EngineRCGF, a Chinese manufacturer of gasoline engines, designs and manufactures engines specifically for the RC aircraft market. T...11/23/2015
    Seagull ModelsMaule Super Rocket 10-15cc ARFWhen Seagull Models announced that they were going to produce not just a model, but an ARF of the Super Rocket, I just had to...11/22/2015
    HobbicoEstes Proto-ZThe Proto-Z is a Blast of micro-sized fun! It's the ultimate user-friendly drone- The fastest, easiset and most economical wa...11/22/2015
    FliteworkEdge 540The Flitework Edge 540 is an electric only ARF airframe with a generous wing span of 66.9" and also beautifully dressed up in...11/21/2015
    Seagull ModelsSteen Super Skybolt 15cc ARFSeagull Models introduced this biplane early on in 2015, and SIG mfg. had a pre-production sample at the Toledo Expo. That pr...11/20/2015
    ST ModelSaltoST model brings us a fun aerobatic glider with the H101 Salto. The self-launch electric glider has no bad tendency and will b...11/19/2015
    RCGF10cc Gasoline EngineRCGF, a Chinese manufacturer of gasoline engines, designs and manufactures engines specifically for 'the RC aircraft market. ...11/17/2015
    Seagull ModelsFunky Cub 10-15cc ARFThe new Funky Cub has some really cool attributes, borrowed from scale aircraft, that should add up to make it a great flying...11/16/2015
    RCGF20cc Gasoline EngineRCGF, a Chinese manufacturer of gasoline engines, designs and manufactures engines specifically for 'the RC aircraft market. ...11/15/2015
    ST ModelASW28ST Model chose to reproduce the Schleicher ASW28, a single seater standard class glider capable of glide ratio up to 45. The ...11/10/2015
    The World Models30% PT-17 Stearman ARF (U.S. ARMY) Some may call me lucky. I would agree! One of the reasons that the PT-17 is so close to my heart is that I have a personal co...10/03/2015
    Bomberfield USA 201527th Annual B-17 GatheringEvery year, the end of the summer brings the big birds back to Monaville, TX, for a festive fly-in weekend at the local RC si...10/03/2015
    HeliMaxVoltage 500 3DThis quad is absolutely not for the faint of heart, but if you·re an established heli pilot with some experience under your b...10/03/2015

      Return to Magazine Homepage

    Copyright MH Sub I, LLC dba Internet Brands Copyright © 2001-2018.
    Terms of Service | Privacy Policy

    Search | Marketplace | Event Central | Local Clubs | Magazine | Product Ratings | New Products | Discussion Forums

    Photo Gallery | Instructor Search | Field|Track|Marina Search | RCU Youtube Channel | | RCU Twitter!

    Member Locator | Advertisers | Hobby Vendor Resources | Rate Manufacturers | Sign In/Sign Up

    Products Videos WattFlyer.com RC Classifieds

    RCU2 | | 0 | 1 | 06:44:10 PM EST | NC