RCU Review: Hangar 9 E-Conversion of Edge 540 33%

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    Contributed by: Greg Covey | Published: January 2005 | Views: 68002 | email icon Email this Article | PDFpdf icon

    Horizon Hobby

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


    • Excellent Quality ARF
    • No gluing needed
    • UltraCote covering
    • Perfect covering alignment match to cowl
    • Removable stabilizer
    • Allows one or two rudder servos

    • Designed for heavy nose weight using Zenoah gas engine

    Part #1 of 2

    My review of the new Hangar 9 33% Edge 540 high-performance aerobatic ARF will include a conversion to clean and quiet electric power. The plane was designed by TOC competitor Mike McConville and is constructed from durable, lightweight balsa and plywood, covered in genuine UltraCote® for an expert look. The Edge 540 includes a two-piece wing and stab that ensures convenient storage as well as easy transport to the flying field.

    Mike's no compromise approach made the new Edge 540 a superior aerobatic performer, flying extremely well in both sequence and 3D-style aerobatics. The new Edge 540 is perhaps the lightest design ever of this size by Hangar 9 making it a good candidate for conversion to electric power.

    Here is what Mike McConville says about the new Hangar 9 Edge 540.

    "Our new Edge 540 is without a doubt our best aerobatic aircraft yet. When designing this model, I incorporated design features and enhancements that have been learned from several years of IMAC and 3D flying.

    The Edge is fine-tuned and tweaked to excel in both precision aerobatics and wild freestyle type 3D, so doing any aerobatics will be easier than it has ever been."

    Read the Gas Version review of the
    Hangar 9 33% Edge 540 on RC Universe - Click here

    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


    This review will combine several topics. First, reviewing the new Edge 540 will include my findings with the new ARF plane design from Hangar 9. Second, the write-up will show a unique conversion to electric power using a technique that is simple and cost effective. My goal for this project will be "1/3 Scale at 1/3 Cost".

    The new Edge 540 is meant to fly at around 22lbs with a Zenoah G-62 engine. The recommended G62 engine weighs about 5lbs and will turn a 22 x 10 prop at approximately 7200 rpm. The 24oz fuel tank is 1.5lbs for a total of 6.5lbs.

    The Actro 40 motor is a maintenance-free direct drive solution.

    The Kohler Actro 40 motor weighs 19oz (1.25lbs) and the 30-cells NiCd needed to power it would weigh about 4lbs for a total of 5.25lbs. That's over a pound less than the glow weight without even using Lithium cells! My plan is to use a 10s2p configuration of the Kokam 2.1AH (20C) cells. This will reduce weight even further while delivering up to 84amps continuous current.

    The Actro 40-4 looks like it can easily deliver power in the 1700 watt range with a current draw between 50-70amps. This could produce a power level in the 80-90 watts per pound using NiCd cells and even better using Lithium cells.

    When you consider that no receiver battery is needed and there will be additional weight loss from no muffler or mount, it seems like a good start that could get optimized to over 100w/lb. and become a great aerobatic performer.

    The Actro Rubber Damper Shock Mount installs easily with M4 hardware

    The Actro motors are top-notch! These German engineered and manufactured external rotor motors require no gearbox and are considered by many to be the very finest outrunners ever made. My guess is that they will easily handle current bursts to 80 or perhaps 100 amps so a 20"-22" prop may be possible with throttle management. The motor mounts easily using the Rubber Damper Shock Mount with M4 hardware.

    The main revelation here is that for a 1/3 scale size plane, it will actually weigh less than its glow or gas counterpart. Also consider that by accepting a compromise in 3D performance, we can greatly reduce the cost and complexity of our conversion from a dual motor and dual ESC setup using a custom-designed gearbox. The aerobatic pattern performance of this electrified 33% Edge 540 will now be within the realm of possibility for many R/C flyers at 1/3 the cost!

    The Edge 540 arrives in two large custom boxes

    The Hangar 9 Edge 540 comes in two big boxes, one for the wing halves and control surfaces and one for the fuselage and fiberglass parts. Everything is individually wrapped in plastic and held in place to eliminate damage from shipping. The quality is excellent and the finished 4-color look is simply fantastic!

    All the fiberglass parts are finished and painted. Shown here for a size comparison is the Edge 540 cowl and pant next to my .60-size Graupner Extra 300S.
    Each wing half stands about 4' high. The covering is top-notch and the construction superb!

    The firewall has a built-in motor mount box that I can mount the Actro motor on using the rubber damper shock mounts. Note the built-in right thrust angle.
    The fuselage reveals a great deal of space inside for components and battery packs. Note that the 2.1AH Kokam cells fit inside the motor mount box forward of the firewall. This looks like and ideal spot for maintaining a proper CG with heavy batteries.
    For the Hangar 9 Edge 540, the recommended servos are the JR 8411 and 8611 digital servos. These are top of the line hi-torque servos for 3D. I'll be using the JR 8411 servos with Matchboxes for ailerons and elevator, and, a single 8611 servo for the rudder. I will also be using a JR PCM computer radio system.

    The JR MatchBoxes are needed when using multiple digital servos on a single control surface since tremendous current draw can result if they are not perfectly balanced. The JR MatchBox synchronizes neutral, direction, and end-points for up to 4 servos in parallel. Additionally, the matchbox servos can be powered through the receiver or a separate battery pack providing flexibility in designing redundancy. I will use a single JRPA900 MatchBox for both wing halves and a second one on the two elevator halves. Using the JR MatchBox, the elevator servo on one side can be reversed in direction to match the other side so it uses only one channel on the receiver.

    To supply current to these hi power servos, I will use a new product from FMA Direct. It is called the VRL12 "Power Force" regulator. It works on a 2s, 3s, or 4s Lithium pack as well as 5-12 NiCd cells. The 6v output can run up to 12 high-torque servos at once and is meant for giant scale applications. Finally, the regulator unit is equipped with an externally mounted ON/OFF switch that is failsafe, meaning, if it fails, the unit comes ON, not OFF.

    Here are some features of the VRLI2:

    • Designed for high current servos and receiver in R/C aircraft
    • Ideal for aircraft using dual radio systems
    • Accepts input from 2s to 4s LiPo or 5-12 cell NiCd/NiMH
    • Switch selectable 5v/6v output at 10amps continuous
      0.15v dropout when voltage goes below 5v/6v setting
    • Three Status LEDs provide battery condition information
    • Failsafe On/Off switch - fails to ON mode
    • Will not drain battery when switch is Off

    Hangar 9 provides the needed hardware for the 33% Edge 540 in a convenient 1/3 Scale Hardware Package at Horizon Hobby.

    Hardware Package Contents:

    HD 1/2 Servo Arm 4-40: JR (8) HAN3574
    3D XL 1/2 Servo Arm 4-40: JR (1) HAN3578
    8-32 Swivel Clevis Horn (4) HAN3614
    4-40 x 4-40 HD Ball Link (5) HAN3616
    Tailwheel, Lg Haigh 12-22 lb (1) OHI160
    Super Hinge Points (4) ROB309
    Dura-Collars, 3/16" (1) DUB141
    Axle Shafts, 3/16 x 2" (1) DUB249
    Fuel Tank, 32oz (1) DUB690
    Pro-Lite Wheels, 3-1/2" (1) HAN308
    Titanium Pro-Links 4-40 x 2-1/2" (1) HAN3552
    Titanium Pro-Links 4-40 x 3-1/2" (1) HAN3554
    Titanium Pro-Links 4-40 x 4-1/2" (1) HAN3556

    The manual for the Edge 540 is well written. It really harps on issues that are important for building and setting up giant scale models so I'll promote them along the way as well. At the back of the manual, there is a very informative "Setup and Flying" section written by Mike McConville. He reveals important information on pre-flight setup, performance tips, mixing, and maneuver instructions. I have everything I need now so I can get started building. I expect a fast build as all the tough, time-consuming tasks are already done in the ARF design.


    Two JR 8411 servos were used for each wing half

    The Edge 540 assembly begins with installing the aileron servos in the wing. I added 12" and 24" extensions to two sets of DS8411 servos; one set for each wing.

    The two ailerons were then glued in place. I used Robart (309) Super Hinge Points since the Edge was pre-drilled to accept these hinges. The hinges were glued with Elmers ProBond since it is easy to use, easy to clean, and, expands as it dries for a solid joint. The manual recommends using 30-minute epoxy.

    Standard Hangar 9 hardware for giant scale planes was used for the linkage. I had a problem with the fit of the JR HD 1/2 Servo Arm on the DS8411 servo. It seemed a bit small but I forced it onto the servo gear and screwed it in place. For a precision metal servo arm, the JR HD 1/2 servo arm did not fit the JR 8411 servo gear well.

    Linkage Parts Used

    • HAN3574 HD 1/2 Servo Arm 4-40 JR
    • HAN3614 8-32 Swivel Clevis Horn
    • HAN3556 Titanium Pro-Links
    • HAN3616 4-40 HD Ball Links

    The JRPA900 Matchbox was used to super fine tune the servo offset after first aligning it physically. The programming was simple using a tiny screwdriver and pushbuttons. The manual recommends using one MatchBox per wing half but I choose to use a single MatchBox for all 4 aileron servos.

    The sequence of the ball link assembly in the manual didn't match the diagram or the picture so I followed the diagram that came with the ball link.

    The wing hinge gaps must be sealed on giant scale planes. I used thick clear shipping tape on both sides instead of the recommended clear UltraCote.

    I decided to jump from the manual's sequence of tail assembly to my favorite
    part of mounting the motor

    The Jeti 77-amp Opto ESC comes with mating connectors that I soldered onto my Actro 40 motor. I will keep the leads as short as possible since I intend to have peak currents from 70-80amps. This means that my Kokam 10s2p 4.2AH pack will be re-wired a bit to reduce lead length and connector count.

    I measured the distance from the front of the motor mount box to the front of the installed cowl to be 8". My first attempt to mount the motor used an AXI mount. I quickly abandoned this approach since it was not sufficiently strong. I was planning to use the 3.75" AXI motor mount and a piece of 1/4" plywood to act as a go-between since the AXI face plate was too small for the Actro motor. Although the parts are simple to obtain and the distance measured 8", the concern was with the strength of the AXI mount. Perhaps it would work if reinforced with cross bar supports.

    To meet my strength goal, each section of the mount from the motor to the firewall must be a larger diameter than the previous section. My next attempt to create a mount would require a visit my local home improvement store.

    The AXI Motor Mount was replaced with a stronger and less expensive PVC adapter

    Many of my ideas are inspired by a lack of craftsmanship and the desire to give readers a simple plan to follow. I learned about the benefits of PVC from a long-time R/Cer in Buffalo, NY. I used a 3" to 4" PVC adapter instead of the box AXI mount. This is much stronger and only costs about $2 at your local home improvement store. The assembly is held in place by three 1/4"x5" hex carriage bolts from plywood wall to plywood wall.

    The thrust angles are already built into the Edge 540 motor mount box. The photo may not clearly show the thrust angle but Hangar 9 did a great job on this plane design. The spinner opening is centered on the motor mount box but not the stock hole opening for the gas engine. I simply used the hole to pass my ESC through to the battery pack.

    I'll be drilling holes in the motor mount box next for air cooling the ESC and batteries. The cowl will not need any cutting or drilling since even the mounting holes are pre-drilled with t-nuts on the fuselage ears.

    Using a 10s Lithium configuration, the voltage is around 36 volts with a light load. My Actro 40 motor at 36v x 70amps produces about 2500 watts. This power level should provide good aerobatic performance.

    A 3/4" thick block was used to extend the motor adapter to a perfect length for the spinner backplate

    I needed 8" from the motor box to the cowl opening so I cut a 3/4" thick block of hardwood to mount just behind the plywood and extend my motor. I also changed to 1/4-20 t-nuts to fasten my three 1/4"x5" hex head bolts. Each bolts weighs 1.1oz for a total of 3.3oz. Perhaps a thinner bolt could be used here but I needed the length and there is no need to save weight this far forward.

    I drilled holes in 5 sides of the mount box on the firewall for air flow into the battery and ESC area. My PVC adapter and wood blocks follow the angle of the built-in right thrust on the motor box.

    Note the perfect covering pattern match from the cowl to the fuselage. This is why I am a Hangar 9 fan!

    I've always maintained that clean electric planes can be built right on the kitchen table. I also found my kitchen chairs very useful in the rudder and gear assembly stages. They swivel in either direction, have wheels to move the plane around, and have padded arms to securely hold the plane.

    My 10s2p Kokam 4.2AH pack is split into two sets; one 4s and one 6s sub-pack

    My 10s2p Kokam 4.2AH pack is split into two sets; one 4s and one 6s sub-pack. The sub packs are plugging into Kokam Parallel Connector boards that I split in two using a Dremel tool. Note that the white shrink wrap allows a probe to be stuck inside for measuring individual cell voltage. It also allows me to re-balance the cells, if needed.

    I removed most of the wire and connectors from stock Kokam 2-cell 2100 packs to create 4s and 6s packs with short connections. The 4s and 6s packs are then paralleled into Kokam Parallel Connector modules that I additionally beefed-up with soldered 12# wire. I wired the two Parallel Connector boards in series for the 6s + 4s = 10s configuration. Note that one of the Parallel boards has 3 plugs. The third plug is for the Yellow connector to feed a 4s voltage to the FMA Power Force regulator.

    The packs sit on a 6"x4" foam pad cut left over from my trailer floor padding purchased at a home improvement store. The foam is very light but high impact meant to walk on for covering a shop floor.

    The entire 20 cell configuration can easily fit inside the motor mount box. I'll hold them in place with more foam upon final assembly. I also added extra wires to the Parallel Connector Modules to ensure a safe 70amp draw. The modules were then wrapped in electric tape so nothing is exposed to short out.

    To switch from my current 10s2p configuration to a 10s3p configuration, I simply create Parallel Connector Modules with additional plugs. The Kokam Parallel Connector modules come with 5 plugs and you just cut off what you don't need with a Dremel tool.

    Note that I discovered if I leave one extra plug unused, it makes for a convenient charging connection on each part of the 10s configuration. One charger can be easily plugged in to charge the 6s section and another charger for the 4s section without the need to pull any cables off. This is very convenient during a full day of flying.

    I used the Red 4" CBA Spinner from Tower Hobbies along with the Actro-Hub ACT266 adaptor from Hobby Lobby. The CBA Spinner adapter is very close to the 8mm threaded Actro prop shaft so a little touch-up with an 8mm tap was all that was needed for a great fit.

    The FMA "Power Force" regulator feeds all the servos, matchboxes, and receiver

    A close-up of my component layout reveals the FMA Power Force regulator, JR receiver, and two JR Matchboxes are mounted with Velcro straps. The Power Force regulator also has the heatsink fins wedged in place against the plywood opening and the 10-amp Dean's input connector is tywrapped to the fiberglass wing bar holder.

    I fired up the Actro 40-4 on the 10s2p Lithium pack (33 cells NiCd) and found that it spins impressively without a prop at only 1/4 throttle! I didn't want to over-RPM the motor so I kept the throttle between 1/3 and off. The FMA PF regulator supplied 6v to the JR receiver, Matchbox, and Jeti 77-amp Opto ESC.

    Note that the antenna wire was fed into a plastic tube that I taped to the bottom of the inside of the fuselage. The single Matchbox shown in the photo will control and balance all 4 aileron servos. My tail section used a second Matchbox for the elevator halves.

    One concern that I had was what the actual cell voltage will be at full throttle. Will I be able to get 2000 watts from my 10s2p configuration? The 4.2AH total is a bit low for drawing 30-50amps. The new 3.2AH cells will become available from Kokam USA this Winter in configurations up to 6s3p. A 10s3p configuration of these cells will provide a 10AH total capacity at current draws up to 180amps! The other nice thing about the new packs will be the built-in cell balancing plug that taps into each individual cell to work with the new chargers...also due out in early 2005.

    My APC 20x11 e-prop and 4" red CBA spinner installed without issue. The elevator servos fit right inside each elevator half.

    I finished the elevator servos and then decided it was time to put the tail and wing together for the first time. I haven't fired-up my power system with a prop yet but have already decided to be proactive by ordering 10 more Kokam 2.1AH cells to make a 10s3p, 6AH configuration. Even if I don't need the current delivery, the extra 2AH capacity and nose weight will be welcome. I also ordered additional APC e-props in case the 20"x11" prop doesn't work out. I have plenty of ground clearance for larger props, if needed.

    I replaced the stock nylon 1/4-20 bolts with some Hillman 1/4-20 furniture bolts that have built-in washers and a hex socket head for easy, no-slip assembly.

    I replaced the stock nylon 1/4-20 bolts with some Hillman 1/4-20 furniture bolts. The Hillman bolts have a built-in washer and a hex socket head for easy assembly. These are available at most home improvement stores.

    I tested the ailerons and elevator control without powering the motor. Everything worked great! The JR Matchboxes made it easy to route all 4 aileron servos to one box. I could conveniently fine tune the servo position with just a tiny screwdriver to select the channel and then use the pushbuttons to vary the offset. The MatchBox on my two elevator servos also let me easily reverse the direction of one so they both work together for up and down movement.

    The big 100" span plane takes up a good portion of my living room!

    I finished up my tail assembly by installing the "monster" rudder. I used the single servo method with a DS8611. The Hangar 9 Edge 540 is designed to use either one or two servos for rudder control. The other side is already covered if you don't use it.

    The gear mains installed fairly easily. It helped to have some long fingers to start the nylock nuts and then you could fit a socket wrench inside the fuselage while tightening it with an Allen wrench underneath. Note that the gear cowl that fits on the fuselage bottom is sheeted foam. Everything seemed to fit perfectly! The fiberglass gear mains were very light! The pants installed without any issues. The wheels are held on both sides with collars. The tailwheel is a large Ohio Superstar assembly that firmly mounts an assembly to the hardwood tail bottom. The wheel is on a tiller bar that is then connected to the rudder via springs to absorb any shock.

    The Actro 40-4 power system was tested outside for safety

    I had an opportunity to test my Edge 540 power system outside when the weather was nice. I did the testing outside for safety and essentially got another lesson in giant scale projects. The power level was incredibly strong and it surprised me! I could barely hold the plane while working the throttle. It pulled like no other plane I have ever tested. Although I got three good test runs in for measurements, I won't be doing it again by myself unless I have an anchor on the tail.

    I was surprised to measure 2500 watts at 85amps on only 3/4 throttle! I wouldn't even try full throttle since this was more power than I was expecting on my 10s2p Kokam 4.2AH pack. The Kokam 2.1AH (20C) cell really held its voltage under a heavy load. I will either try things as they are now and use good throttle management or perhaps reduce my prop size or pitch. The plane should fly well at only 30-40 amps.

    I'll still plan on switching to a 3p configuration for increased capacity and weight but I may consider also switching to an 8s or 9s voltage since I like how my APC 20x10 e-prop performed. The prop had been balanced before I mounted it and the vibration was very light at 3/4 throttle. I was now curious to see where the plane balanced.

    Ground Testing:

    Loaded with Lithium and failsafe switch mounted, I was ready for my first ground test

    I was ready for my ground test at lunchtime during the work week. The Edge 540 just fit into my Ford Explorer. I converted my Lithium pack to a 10s3p configuration of Kokam 2.1AH (20C) cells for a total capacity of 6.3AH that can deliver over 120amps continuous. I will not be stressing the pack and will have a reasonable flight time as well as some added nose weight. My initial CG testing without the wings installed told me that I needed the extra weight up front from my additional Lithium cells.

    Here are some weight measurements I made before the ground test:

    • 10s2p Kokam 4.2AH (20C) pack = 59oz (3.7lbs)
    • 10s3p Kokam 6.3AH (20C) pack = 88.5oz (5.5lbs)
    • Wing half RTF = 37.5oz
    • Edge 540 RTF less wings and batteries = 160oz (10lbs)

    All up with the 10s3p Lithium pack, my Edge 540 is RTF at 20.2lbs. It would have been 18.4lbs with my original 10s2p pack which was very close to my original target goal. I mounted the failsafe On/Off switch per the manual.

    The Edge 540 is submitted to a complete ground test for the first time

    The first ground test on my Edge 540 gave us some good information and I discovered that there is still some work to be done. The vertical stabilizer looks like it was damaged in shipping so I need to remove a portion of the covering and see if any gluing is needed. I had noticed that the rudder fit was not as perfect as any of the other sections but ignored it at the time.

    I'm slightly tail-heavy yet so I'll try moving the 1.2lb Lithium 6s pack that currently sits outside the motor box into the cowl area. I also need to open up an air exit on the bottom of my cowl. My spinner spacer is slightly warped causing a minor wobble so we'll replace the 5 washers with a single steel spacer.

    Although I could taxi around the field without issue and throttle up to 3/4 while holding the tail, at full throttle, the ESC shut off after we had throttled off for a few seconds before resetting. I may try cutting 1/4" off of each prop tip or order some APC 20x8 props to reduce the current draw by using a lower pitch.


    We took a ground test video for the Edge 540. It was very windy out so we kept the speed to a minimum. The lot behind our parking area is a bit rough to taxi on, but, it worked well and showed me that the plane was rugged.

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