RCU Review: Hangar 9 Edge 540 33% Cnversion Part 2

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    Contributed by: Greg Covey | Published: August 2005 | Views: 34405 | email icon Email this Article | PDFpdf icon

    Manufacturer Info

    Horizon Hobby

    4105 Fieldstone Rd..
    Champaign, IL 61822 USA
    Tel (800) 388-4639


    Edge 540 Cost Analysis

    Required Parts

    Hangar 9 33% Edge 540 plane* = $850
    1/3 Scale Hardware Package* = $150
    MatchBox Twin Pack* = $110
    Seven DS8411/8611 Servos* = $805
    Wing/Tail Cover Set* = $75

    Glow Version

    Zenoah G62 Engine* = $425
    Pro Receiver Battery* = $32

    Electric Conversion

    AXI 5330 Motor = $250
    Jeti 90-amp ESC = $250
    FMA Power Force regulator = $80

    Fuel References

    Glow Fuel per gallon = $15
    Gas Fuel per gallon = $2
    10s 6AH Lithium pack** = $800
    30-cell GP 3700NiMH pack***= $327

    * = Horizon Hobby Street Price
    ** = cost based upon $40 per Kokam 3.2AH cell at Horizon Hobby
    Kokam 3.2AH pack at Horizon Hobby
    *** = cost based upon three 10-cell packs at Diversity Model Aircraft
    GP 3700 Packs at DMA

    - Note the lower cost of gas over glow fuel.
    - The approximate gas usage is about 1/3 gallon per flight.
    - Note the lower cost of NiMH over Lithium although only 1/2 the capacity.


    Part 2 of 2

    When I started working on my new approach to convert the Hangar 9 33% Edge 540 to electric power, springtime was just around the corner. Our thoughts in the northern U.S. and Canada were turning from building to flying. The Nuremberg Toy Fair had just been held in Germany, the WRAM Show was the following weekend in New York City, and the Toledo show was at the end of the following month. Manufacturers, vendors, and hobbyists were all starting to buzz about the new products for 2005.

    In part 1 of my conversion article, my goal for the project was to achieve aerobatic performance on a 20lb plane at a more reasonable cost and lower level of complexity; hence the theme, "1/3 scale at 1/3 the cost". Although I came up a bit short on my first attempt, I was not discouraged. In fact, I was very pleased with the Edge 540 design and ease of assembly. My power system was simple and cost-effective. It seems to only have one flaw; an under-rated ESC. This was not the fault of the ESC design but rather my inexperience with giant-scale power systems.


    Manufacturer: Hangar 9
    Kit Name: Edge 540 33%

    Wing Span: 97 in
    Length: 87.9 in
    Wing Area: 1760 sq in
    Glow Flying Weight: 22-24 lb
    Engine Size: 62 - 80cc
    Radio: 4 channels
    Servos: 9


    My feeling is that most pilots fly only aerobatic patterns and giant scale 3D is best left for the professionals like Mike McConville or other IMAC competitors. If we only want this level of performance, we should be able to achieve it at a more reasonable cost.

    It was time to start "Part 2" of my quest for "1/3 Scale at 1/3 Price" on the Hangar 9 33% Edge 540 conversion to electric power. In part 2 of my conversion article, in addition to my ESC upgrade, I'll cover some new advances in R/C technology that will not only simplify the design even further but also continue to reduce the cost or provide more alternatives to choose from. I will also have some exciting new flight performance video showing the electric Edge 540 in many aerobatic maneuvers.

    For reference, here is the link to my review article on Part 1 of the conversion in the
    RCU Online Magazine: Hangar 9 Edge 540 E-Conversion, Part 1

    Here is an overview of some of the areas that will be covered.

    • Comparison of Actro 60-175 and AXI 5330 motors
    • Jeti 90-amp Opto ESC
    • Protection and storage
    • Tail Trap from JL Power Products
    • Cost analysis
    • NiMH cell alternatives to Lithium
    • Sport/Pattern Flying video

    Last, but not least, the plane just never flies right without a pilot. Over the Winter, I painted the 1/3 Scale Civilian Pilot from Horizon Hobby to go in my Edge 540. Now we're ready to go flying!

    Changes in the Conversion Design

    My cowl is now fully "dressed" with the official RCU logo made by RC Graphics Zone
    Note the "Danger High Voltage" label to keep my glow-powered buddies at bay

    My Parallel Connector Modules have been re-fitted to allow a spare plug on each bank, 6s and 4s, for easy charging. After the hatch is removed, you simply pull the ESC connector and then plug into the 4s module for charging and the 6s module for charging. The packs up front are secured on both sides by Velcro so I can adjust the CG as needed for testing the 1/4lb heavier AXI 5330 motor. Additionally, the 2.1AH cell packs can be easily swapped with newer SKYVOLTS packs from FMA Direct when they become available.

    • AXI 5330 = 23oz
    • Actro 40 = 19oz

    New Motor Selection:

    Electric power guru, Steve Neu, published information in his "Power On" column in the March 2005 issue of Quiet Flyer magazine which plots the AXI 5330 and the Actro 60 motor power curves. (see page 60) Both motors had efficiencies around 87% at 50amps on a 10s Lithium voltage under load of 35 volts. This provides an output power to the prop of 1522 watts with an input power of just 1750 watts. Note that Steve's 50amp (1700 watt) limit was likely due to the Jeti 77-amp ESC on a 10s Lithium voltage of 35v (been there, done that in Part 1). He suggested that the AXI motor can likely handle higher currents if you keep an eye on motor cooling.

    After reading Steve's column, I was now convinced that the AXI 5330 motor is the correct choice for my Edge 540 conversion. For only $249 at Hobby Lobby, including several prop adapters, this motor will be hard to beat for reducing the cost of giant scale conversions to electric power. The AXI 5330 motor runs at 87% efficiency for just under 2000 watts. This means that little power is being lost as heat. I expect to easily have 3000 watt burst power levels which will provide 150 watts/lb. on my Edge 540. I selected the 5330/18 because it will have thicker wires to handle more burst current.

    For my conversion project, the theme is about lower cost and the AXI 5330 at $250 U.S. is much lower in price than even the smaller Actro 40 motor at $350 U.S. The Actro 60 is even more costly at $480 US at Hobby Club.

    Protection for the Plane:

    To help protect my 1/3 scale Edge 540 during transport or even when moving it through doorways, I used the Wing and Tail Cover Set (HAN6010) from Horizon Hobby. Each set includes nylon padded bags for two wing halves, the horizontal stabilizers and the vertical stabilizer. The wing bags comes with a Velcro strap for a secure fit that won't let the bag slip off. An additional strap is used to help carry the bag. Big models are a big investment and Hangar 9's wing bag set is a handy way to help protect that investment while still looking great!

    Protection for the Packs:

    Shown here is my Kokam 3-cell, 3.2AH pack wrapped in an IMPAD pouch. A simple Velcro strap holds the pack inside the pouch. This is a good technique for protection when pack heat is not an issue.
    When pack heat is an issue, IMPAD end-caps can be made to allow air flow through the cells in the pack while protecting it from a blunt force. The new Skyvolt packs from FMA Direct allow air to flow between the cells for maximum performance and longevity.

    Exposed lithium packs can be risky. You risk damaging the pack in the event of a crash which reduces your investment security at the same time as it increases the risk of fire. I still crash on occasion so my plan for protecting the exposed packs is to wrap them in a super impact absorber from FMA Direct called IMPAD. It is packaged in 12" x 6" sheets and can protect an egg from cracking when dropped at four feet off the ground.

    When pack heat is not an issue (e.g. you are not stressing the pack in the application), the pack can be wrapped in an IMPAD pouch using a simple Velcro strap to hold the pack inside the pouch. When pack heat is an issue, IMPAD end-caps can be made to allow air flow through the cells in the pack while protecting it from a blunt force. For either technique, I used clear shipping tape to form the pouch or caps.

    Motor Mounting:

    To mount my AXI 5330 motor, I took my usual trip to the local home improvement store. I found that 4" PVC caps (Schedule D) were flat on the ends. If I connected two caps to a custom cut section of 4" PVC pipe, I could extend the motor to the required 5-3/4" needed for the spinner backplate when using an AXI 5330 motor.

    The concept was simple, light, solid, adjustable in length, and most of all, very inexpensive!

    The AXI 5330 motor comes with a sticky back template for mounting. I simply placed the decal on a 4" cap after first sanding the lettering on the surface flat.

    For some added support, I used two small metal strips in addition to using washers with my M4 screws. Locktite was used on all threaded surfaces. I pulled as hard as I could on the motor and it would not budge. I felt confident in the ruggedness of my PCV mount.

    I mounted the other end cap to the firewall using the same 1/4-20 t-nuts from my original mounting scheme but with some short screws and washers instead of the long bolts. I didn't glue the PVC pipe to the end cap because the fit is so tight that it must be tapped with a hammer to be fully inserted. I did, however, secure it with four #8 sheet metal screws, one in each quadrant.

    Note that the mount may not look centered but the thrust angle built into the plywood motor box makes the prop adapter come out centered through the cowl.

    I finished mounting the AXI 5330 motor by tapping the 4" PVC end cap onto the pipe with a hammer. I then added the four #8 sheet metal screws to keep it secure. The alignment to the cowl was perfect but I needed to open the holes on my red CBA 4" spinner aluminum backplate and APC 20x11 prop to the wider 12mm shaft on the prop adapter. This will require using a drill press or lathe to keep the holes centered. Since the AXI prop adapters are already tapped for a M4 spinner cap , so no adapter is needed. To drill out the perfect size center hole in my prop, I used a 15/16" drill bit for my 12mm adapter.

    Jeti 90-amp ESC:

    A key piece of my lower cost power system for giant-scale conversions is now sold through Hobby Lobby. The new Jeti Advance 90 PLUS ESC is a solid 4oz controller that should handle continuous power levels up to 4200 watts with little cooling.

    Unlike the other Jeti Advance PLUS ESCs, the 90-amp ESC comes without shrinkwrap for superior heat release and mounting tabs with pre-installed grommets.

    Since my Kokam 10s3p 6.3AH Lithium pack is also rated for 4200 watts continuous (35v * 120a), the weak link in the power system is now the AXI 5330 motor. By weak, I mean that the motor will handle 2000 watts continuous and probably up to 3000 watts peak based upon reports from competitors in Europe. The overall result will provide a power level of 150w/lb to my 1/3-scale Edge 540 at an unprecedented lower cost.

    I set out the components for my power system and started preparing the ESC by soldering the mating connectors for the AXI motor and a Dean's Ultra connector for the battery. The ESC mounted easily with some servo tape and a screw through one of the grommets into the wooden motor box. The wires were not long enough to use the other eyelets and I felt that they were not needed. The ESC was now positioned directly in the air flow through the cowl.

    The 6s and 4s battery packs mounted as before except this time I used some Velcro straps to secure the outer packs. I had an additional 8oz up front over my last power system due to the heavier AXI motor and Jeti ESC. This could only help move the CG toward the recommended spot as I was a bit tail heavy with my old setup.

    The new Jeti Advance PLUS ESC was easy to set up with the compact Jeti Programming Card. You simply set the jumpers, connect the control cable, and power up the ESC for 1 second until you hear a beep. The credit card size programming device can be easily stored in your field box for future changes.

    I used the following settings.

    • Li-XX Battery
    • Low Cut-off voltage
    • Slow Cut-off type
    • Brake Off
    • Hard Timing for Outrunners
    • Linear Throttle curve

    I made up some EPP foam caps to cover the extra connector pins when not recharging the Lithium packs. My 10s3p 6.3AH Lithium pack is split into a 4s section and a 6s section which requires two chargers to recharge the pack. This same setup can be used when I switch to the newer Skyvolts packs from FMA Direct with taps for cell balancing. One advantage of using the 4s/6s split configuration is that I can supply power to my FMA Power Force regulator to test the servos without arming the powerful motor. This level of safety is required for indoor testing of the control surfaces.

    My aluminum backplate and prop fit perfectly after boring them to 12mm (15/16") for the AXI shaft. I discovered that the center of the shaft is tapped for an M4 x .7 screw. To mount my large 4" diameter CB/Tatone spinner, I would need an M4 screw about 90mm long!

    Finding a 90mm long M4 screw proved too difficult in the U.S. I gave up after only finding a 70mm length and changed my technique to use a #10-32 screw. The length needed is 3-1/4" long but 3-1/2" long will work also. I decided that re-tapping the M4 threaded hole in the AXI 5330 prop adapter is not all that unreasonable. A size #10 is the next larger American size from an M4 thread. The adapter was easily re-tapped to the American standard size #10.

    I connected my wattmeter and it appeared that my APC 20x11 prop was a reasonable choice after all. I measured 2700 watts at 86amps consistently on four 10 second bursts of full throttle. I was ready for my maiden flight with the new power system!

    Flight Time

    Test Flights

    We flew the Edge 540 yesterday for the first time with its new power system and it performed flawlessly! Our first flight was a basic trim and a few simple aerobatic maneuvers before landing just to get "the monkey" off our back from last fall. The second flight was without charging and we spent some time learning the plane and getting more comfortable with it. We brought it in early so we could get to know the flight duration by measuring battery voltage. The first two flights were about 7 minutes total and we used about 1/2 the 6AH pack capacity. The new Jeti 90-amp Advance Plus ESC seemed to work great!

    After charging for about 30 minutes, we had a third flight and pushed the plane harder this time. The power system appears to provide stronger aerobatic maneuvers like giant loops, knife edge, hammer heads, and such, but does not have sufficient power for good 3D hovering and pullout. This was not too surprising considering the small size of the 20" prop. Again, about a 7 minute flight used only about 3AH. The planes cruises along nicely at only half throttle. I was a bit nose heavy this time after the power system changes using the heavier AXI 5330 motor and the fact that I added 6oz of lead inside the cowl. I will try removing 3oz of the lead for the next test flights.

    Here are my measurements from the first series of flights:

    • 2700 watts at 86amps
    • 6500 RPMs
    • APC 20x11 e-prop

    After landing, I felt the AXI motor with my fingers, and, although it was hot, I could keep my fingers on the motor so it wasn't really hot in terms of the motor temperature. This was a good sign for motor longevity.

    After a quick charge off my truck battery, the big Edge 540 was sent on its third flight.

    The Edge 540 looks fantastic against the blue sky!


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