RCU Review: FMA and Hobbico FMA Low Voltage Flight Pack

More On This Product

  • Research Airplanes
  • Research Boats
  • Research Cars
  • Research Helicopters
  • Research Engines & Motors
  • Research Radio Equipment
    Contributed by: Greg Covey | Published: December 2004 | Views: 19627 | email icon Email this Article | PDFpdf icon

    FMA Direct
    5716A Industry Lane
    Frederick, MD 21704 USA
    Web: www.fmadirect.com

    Distributed Exclusively by:
    Great Planes Model
    P.O. Box 9021
    Champaign, IL 61826-9021
    Web: www.hobbico.com

    FMA Low Voltage Flight Pack

    FMA Direct has introduced a new line of LV (low voltage) products that can operate on a single Lithium cell or with 3 to 5 NiCd cells. The M5LV Receiver operates on as little as 2.7V, but it's a full-fledged five channel, dual conversion unit — so you can fly anywhere, anytime without concern about RF interference or limited range.

    Couple the M5LV receiver with the low voltage Super 9LV Speed Controller and you have the best interference rejection single cell system that the industry has to offer. The Super 9LV operates on 2.5 to 8.0V with 3V low voltage cutoff to prevent over-discharging cells. End point adjustment gives you full throttle stick travel, and with no brake the Super 9LV is ideal for electric helicopters. It's available with 1.25mm or standard J-type connectors. D.I.P. switches are provided to change the throttle End Point Adjustment (EPA) and to disable the Low Voltage Cutoff (LVC).

    The M5LV features:
    • Five channels
    • Low voltage
    • Superior interference rejection
    • Light weight
    • Dual conversion
    • Full range
    • Single cell operation

    The Super 9LV features:
    • Auto or manually set voltage cutoff
    • Throttle end point adjust
    • 1.25mm and standard J-type connectors
    • 2.5 to 8.0V operation
    • 3V low voltage cutoff

    The FMA LV Flight Pack uses several of the PS 20 servos, the smallest, lightest sub-micro servo on the market.

    The PS20 Servo features:

    • Only .2oz.
    • 12.5 in/oz.@4.8v
    • 15.5 in/oz.@6v

    The popular Hobbico SWARM free-flight plane
    was converted to R/C
    The SWARM provides easy access for wiring and placement of components

    For my FMA LV Flight Pack project, I decided to convert the popular Hobbico Swarm electric free-flight plane since it is inexpensive and runs on a 3-cell (3.6v) NiCd pack.


    Wingspan: 31.5" (800mm)
    Fuselage Length: 24.4" (620mm)
    Fuselage Height: 3.4" (85mm)
    Elevator Adjustments: 1/16" (1-2mm) up or down
    Motor: 180 size
    On-Board Battery: 3.6 volt

    The Hobbico Swarm will provide an easy conversion from electric free-flight to R/C. The plane is sufficiently open and easy to access the various sections. The cowl is held in place by two screws and the rudder easily removes with a single screw making it easy to convert and re-assemble.

    The stock 1.0oz 3-cell NiCd pack was replaced by the 0.4oz Kokam 340 pack

    The 3-cell NiCd pack was removed by cutting out the entire rectangular circuit board containing the On/Off switch and charger jack assembly. It weighed 1.0oz compared to the 0.4oz single cell Kokam 340 pack in the LV Flight Pack.

    I hooked up the motor wires to a variable bench supply and made the following measurements:

    3amps @ 2.5v
    5amps @ 3.6v

    This appeared to be a good fit for the Kokam 340 cell in my LV Flight Pack since it can deliver up to 6amps continuous, if needed.

    The stabilizers can be removed with a single screw

    The Swarm vertical stab can be removed with a single screw. This makes it easy to cut out the rudder and elevator from the stabilizers on the bench. I simply taped my control surfaces in place after first cutting a 45 degree wedge into the leading edge of the rudder and elevator.

    Plenty of downthrust is built into the stock motor mount. The cowl can be removed with only two screws but I see no need to do this now since the motor wires already run back into the open fuselage.

    The motor wires were soldered to the FMA Super9LV ESC. The plus (+) side to red and the negative (-) side to black.

    The SWARM wing is already reinforced by a plastic piece that uses sticky-back tape and fits into the custom saddle in the fuselage.

    Two PS20 servos were mounted into the removed battery opening

    I mounted the two PS20 servos in the opening created by cutting out the stock battery board. A few pieces of balsa were used to separate the servos and provide a framework to glue onto the foam. I used the UHU Por glue which is foam-safe and dries in just minutes.

    The FMA M5LV receiver was placed in the remaining part of the opening left by removing the original battery board.

    I glued some light micro-horns into the rudder and elevator from LighterRC.com Other products like the Dubro micro hardware series may be available at your local Hobby Shop.

    The antenna was taped along the fuselage bottom and the landing gear mounted with just a single screw. They are quite sturdy!

    The control rods (very light weight) were made from carbon rods and small pieces of wire that I added a "Z" bend too. The wire was held to the carbon rod with shrink tubing. This creates a light set of control rods with adjustable linkages.

    Although it is a tight fit, the rod length can be fine adjusted by pulling or pushing on it with some pliers. First center the servos and then adjust the rod length to center the control surface. Linkage adjustment is made easy by the shrink tubing.

    The Super9LV ESC was mounted with servo tape and the single cell Kokam 340mAh pack fits up into the motor area for a perfect CG setting.

    My Hobbico SWARM was RTF at 6.6oz using the FMA LV Flight Pack. This was about half an ounce over the stock free-flight weight.

    The SWARM was hand-launched over grass and flew great!

    The converted free-flight plane flew great and I was very happy with this conversion using the FMA LV Flight Pack! Hobbico seems to have replacement parts for all sections of this electric free-flight plane except for the motor. The FMA LV Flight Pack performed glitch-free.

    I did, however, disable the LV cutoff feature by turning DIP switch #2 off. While this is not recommended, it did work for me as a quick field fix. The real fix should be to solder a .01uF noise suppression capacitor across the motor terminals, and, if needed, solder another capacitor from each terminal lug to case ground. The stock motor is a low voltage Mabuchi Speed 180 (FF-180SH-4022). The shaft is 2mm and it weighs 32g (1.1oz).

    The stock Speed 180 motor is held in a custom tray by a rubber band

    The cowl can be removed with only 2 screws and a custom 180 plastic motor mount holds the motor with a rubber band. It can be easily replaced and held in position by a rubber band. Note the built-in downthrust for free-flight.

    I hand-tossing the Hobbico SWARM over a grass covered field for safety.
    The LV flight pack provided glitch-free performance that resulted
    in a relaxing and enjoyable flight!

    Alternate Motor/Cell Count:

    The Promax 180 motor from MPI is a good replacement but requires a 2-cell Lithium pack

    Motors that operate on a single Lithium cell with the direct drive power of a Speed 180 are difficult to find. At the time of this write-up, Hobbico did not spare the Mabuchi (FF-180SH-4022) stock low-voltage Speed 180 motor in the SWARM plane. I did find a replacement motor at Maxx Products Incorporated (MPI) called the Promax 180 (ACC3180). This 7.2v motor comes with the three capacitor filter mentioned above to eliminate noise that may cause premature shutoff by the ESC's LVC circuitry.

    I measured 2.7 amps (15w) using a 2-cell Kokam 340mAh pack at full throttle with the stock SWARM prop. This provided plenty of power for the plane but the 2-cell pack would cause servo jitter on a full charge unless the motor was running. I found that by quickly enabling the motor after power-up, everything worked fine and I had several great flights. The reason for the servo jitter was the excessively high voltage from the 2-cell pack since the Super 9LV does not have any BEC regulator. It feeds the battery voltage directly to the servo and receiver. A better choice for this 2-cell setup would be to use the Super 9 instead of the Super 9LV. Both ESC versions are available with either the smaller 1.25mm connector or the standard J-type connector.

    Since the Promax 180 has a much shorter 2mm drive shaft, I needed to cut my cowl end about 1/4" to make it fit.

    Perhaps other direct drive options with come available in the future for this size of plane. Here is a list of some motors that can operate on a single Lithium cell.

    Peck 035 (Rev-Up) - 1.7amps @ 3v using a 6x3 prop
    Graupner Speed 280 - 1.70amps @ 3v using a 6x4 prop
    Speed 400-7.2v - 1.8amps @ 3v using a 6x4 prop
    KP-01 geared - 1.9amps @ 3.7v using a 6x4 prop
    Mini-6 Hiline - 1.9amps @ 3.7v using a 6x4 prop
    GWS LPS-RLC-A - 6x4 prop
    MPS-2A DJ Aerotech - 6x4 prop

    The new line of FMA LV (low voltage) products offer lightweight components with full performance features. The M5LV Receiver and Super 9LV ESC feature dual-conversion filtering and low-voltage cutoff so you can safely fly anywhere, anytime without concern about RF interference, limited range, or over-depleted Lithium packs.

    The PS20 servos weigh only 0.2oz while offering the full performance of any sub-micro servo.

    The LV Flight pack offers the modeler or novice a new choice for outfitting smaller parkflyer planes or converting inexpensive electric free-flight planes to R/C. Although the choice of single-cell low-voltage motors is limited, there does exist a few of them like the Mabuchi Speed 180 motor used in the stock SWARM and the MPI ProMaxx 180 replacement. See the Alternate Motor section for a list of other possible choices.

    My main goal here was to promote some ideas and inspiration for using the lightweight FMA LV Flight Pack in your own conversions or existing R/C airplanes. Have fun in your own backyard or open field down the street by enjoying the exciting world of micro-flight R/C!


    FMA Direct
    5716A Industry Lane
    Frederick, MD 21704 USA
    Web: www.fmadirect.com

    PO Box 220082
    Milwaukie OR 97269
    Web: www./lighterrc.com

    Distributed Exclusively by:
    Great Planes Model Distributors
    P.O. Box 9021; Champaign, IL 61826-9021
    Web: www.hobbico.com

    Comments on RCU Review: FMA and Hobbico FMA Low Voltage Flight Pack

    There are no comments

    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

    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

    RCUniverse is a service of Internet Brands, Inc. Copyright © 2001-2017.
    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

    RCU4 | | 0 | 1 | 03:56:07 AM EST | NC