RCU Review: The Wings Maker Ultimate 40 E-conversion

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    Contributed by: Greg Covey | Published: June 2009 | Views: 50837 | email icon Email this Article | PDFpdf icon
    The Wings Maker Ultimate 40

    Review by: Greg Covey
    Flying Photos: Papa Jeff Ring
    Video Pilot: Lynn Bowerman

    The Wings Maker
    Distributed On-line at:


    2403 Research Drive
    Livermore CA 94550


    Complete Kit with hardware
    Great ARF value and looks
    Wing Incidence Guides
    Parts Bags Numbered
    Superb Covering &
    Flying Performance

    Wheel Pants Require Alignment
    The Wings Maker - Ultimate 40

    The new Ultimate 40 performance biplane from The Wings Maker is now available on-line. It is made from top quality balsa and plywood construction and comes with all hardware and accessories. The built-up upper and lower one-piece wings comes with premium hand iron-on covering film in an exciting new color scheme!

    I'll be converting this .40-size model to clean and quiet electric power for my review.


    • Wing Span : 42 in / 1060 mm
    • Wing Area : 578 sq in / 37.3 sq dm
    • Flying Weight : 4.5 lbs / 2050 g
    • Fuselage Length : 39.5 in / 1000 mm
    • Engine Required : 2-stroke 0.40 - 0.46 or 4-stroke 0.52 - 0.56
    • Radio Required : 4-channel radio w/ 3 standard servos and 1 mini servo

    Key Features:

    • Top quality balsa and plywood construction
    • Light weight but strong for aerobatics maneuvers
    • Painted fiberglass cowling and wheel pants
    • Built-up one-piece wings with symmetrical airfoil
    • All necessary hardware included
    ARF Contents :

    The Ultimate 40 ARF comes very well protected in its box and every part is sealed in plastic. The plane is beautifully covered and detailed. The kit includes built-up upper and lower one-piece wings and an incidence guide set for checking the alignment between the two wings.

    The fiberglass cowl is painted and comes with a plastic guide for cutting sections away when a glow engine is used. The wheels, fiberglass pants, spinner, and fuel tank are also included. The opaque canopy eliminates the need for a pilot.

    An 13-page manual with detailed drawings and a decal sheet are also included. The manual reveals detailed linkage assembly and instructions to properly set incidences. It clearly states the proper throws and CG settings.

    After opening the large bag of parts, it was nice to see the smaller bags with numbers on them that matched the instruction steps in the manual. This makes it easy to find the right set of parts for each step and is a nice feature from The Wings Maker!


    A closer look at the fuselage revealed the solid but light construction techniques. A hardwood slat keeps the vertical stabilizer channel safe from breakage during shipment. Blue dots mark where the covering should be cut for the horizontal stabilizer.

    The firewall has pre-mounted T-nuts for the supplied glow engine mount. T-nuts are also pre-installed for the gear mains and securing lower wing.

    Electric Conversion:

    The power system components for my Ultimate will consist of an AXI 4120/14 outrunner motor, a 60-amp ESC like the E-flite EFLA1060 Pro Brushless ESC or FlightTech 60A ESC, a new FlightPower EON28 6s 3350mAh LiPo pack, and APC 11x7 e-prop.

    The Ultimate 40 target weight is 90oz (5.6lbs) including the 18oz Lithium pack. The static current should be around 53amps for a power level of around 1100 watts using an APC 11x7 e-prop. The target power to weight ratio will be about 1100w/5.5lbs = 200w/lb. This will really make the Ultimate 40 perform well without stressing the components. The EON28 3350mAh pack can deliver up to 94 amps continuous and we should only be drawing in the mid-50s.


    The advantage of using a single 6s pack is that it allows you to recharge the battery in the plane without needing more than a single MPI arming switch to disconnect the battery from the ESC. This can be done safely by using a smart balancing charger like the FMA Cellpro 10S.

    When using two packs in series, you must either charge only one pack at a time or break the series link between the packs in order to charge them at the same time using two chargers powered by a single car battery. If you don't do this, then a ground loop will exist and damage one or both chargers. In essence, you need to use two of the MPI arming switches or have some access hatch to disconnect the Dean's Ultra connectors; one from the ESC and one from the other pack in series

    On smaller scale planes like this Ultimate 40, it is often difficult to remove the lower wing to recharge during flights. I have found it much easier to assemble the plane once for the weekend and recharge the battery inside the plane between flights.

    To mount the electric motor, the stock metric T-nuts were first removed and then #8-32 T-nuts installed into the new positions marked from the AXI radial mount. I used 1" (HLH8855), 1/2" (HLH8854), 1/4" (HLH8853) spacers, and 3" (HLH8875) #3-32 screws from Hobby Lobby. Note that two 1" spacers would likely work here as well but I prefer to have the cowl in tight against the fuselage.

    The APC 11x7 e-prop was mounted with the supplied spinner. All hardware was included for the cowl and spinner.

    Spark-free Arming :

    My Ultimate 40 will be easy to arm using the MPI 6970 High Current Arming Switch. I am also adding an anti-spark feature to keep the arming pin from getting pitted. Any electric power system using a 6s LiPo voltage or higher creates a sizable spark when connecting the battery to the ESC. This can be eliminated by first connecting a 100ohm 1w resistor across the line to charge the ESC capacitors and then connect the battery via an arming switch or direct Dean's Ultra plug.

    Since my E-flite ESC came with an On/Off switch, I decided to use it for the anti-spark switch instead. It is not a fail-safe On/Off design for the ESC so it poses a weak link that could turn off the radio system in flight if the switch ever went bad. By removing the switch and soldering the On/Off wires together on the ESC, it will always remain on as long as power is applied.

    The ESC was mounted to the bottom of the fuselage through a slot I created with a Dremel tool. It is held in place with servo tape on the top side and a wedge of balsa CA'ed inside the fuselage to keep it from moving. I will be creating an opening in the cowl for air to pass by the ESC as it exits. In this manner, air flow from the front of the cowl will cool both the motor and ESC. Additional holes into the fuselage will help cool the battery where an air exit will be made in the bottom tail.

    To arm the system, simply turn ON the switch and then plug in the arming pin...spark free!

    ARF Assembly:

    The assembly starts with the lower wing. The ailerons were attached with Zap thin CA on the hinges and a small amount of 5-minute epoxy where the control arm inserts into the aileron. The thin CA soaks into the fiber hinges and then into the balsa slots for added strength so remember not to use any CA kicker accelerator on this step.

    I used a Hobbico CS-35 Mini BB Servo for the aileron control. This high power (54 oz-in) mini servo weighs only an ounce and will easily move all four ailerons on the Ultimate. All the linkage was supplied including the keepers. The upper wing ailerons were then CA'ed in place. Both wings already come with the strut cabanes glued in place.

    The horizontal stabilizer is glued in place first, followed by the vertical stabilizer. The fins already have the covering removed so they can be glued with either thin CA, epoxy, or white glue.

    The elevator halves and rudder are attached by the hinge material, via the pre-made slots, and then secured in place with thin CA. I had no alignment issues and the pieces all fit well.

    The tailwheel assembly was complete and easy to install. I drilled 2mm holes for the screws and rudder hole. The holes were coated with some thin CA before installing the assembly and I used Pacer Z-42 thread locker on the set screws before tightening them. Remember to slide the one wheel collar against the plastic base before tightening it so that it helps absorb shock on landings.

    The elevator control rods are combined together using the supplied joiner. Each end is bent at a right angle to keep it from slipping out under force. I used Pacer Z-42 thread locker on the three nuts before tightening them in place.

    The elevator and rudder control horns were mounted into the pre-drilled holes of the control surfaces. All the hardware was supplied and the pre-mounted tubing ends even had the fuselage covering sliced at the opening so the control rods could slide through. This provided a very clean look. However, I needed to open the holes in the control horns for the clevises using a 5/64" bit. All three clevises were installed into the second hole from the outside or second farthest from the control surface.

    The other ends of the elevator and rudder control rods attach to standard size digital servos. The supplied keepers create a simple yet secure connection to the servo arm. The unused position was for the glow engine throttle servo.

    A hardwood platform was then glued in place with epoxy. It was supported on the bottom by short blocks glued to the fuselage top. I then covered the platform with a Velcro strip which was securely CA'ed in place. My 6-cell EON28 3350mAh pack fit perfectly as it was supported on all sides. A small piece of flooring foam will be wedged in between the LiPo pack and the hardwood slat I used to reinforce the former.

    Landing Gear:

    The gear mains assembly started by mounting the wheels and pants. I needed to sand the one side of the wheel hub about a 1/4" down with my Dremel tool for a perfect fit inside the pant. All the hardware is supplied and fit well but the pants to not have pre-drilled holes so you need to align them yourself.

    The mains screwed into pre-mounted T-nuts in the fuselage. I use Pacer Z-24 thread locker on the grub screw collars and the three screws holding the mains to the fuselage. My Ultimate 40 could finally stand on its own wheels.


    The canopy comes with pre-drilled holes and a roll of double-sided tape for east installation. The rubber eyelets keep the canopy plastic from cracking and the double-sided tape provides a good seal to prevent wind from entering along the front and sides.

    Lower Wing:

    The lower wing aligned itself with the pre-installed wooden dowel on the leading edge and the pre-drilled hole in the hardwood plate on the trailing edge. The seam was perfect and the wing was held securely in place with a single M4x25 screw into a pre-installed T-nut in the fuselage.

    Note that an air exit opening was cut into the cowl bottom with my Dremel tool.

    Wing Incidence and Cabanes:

    Traditionally, one of the more difficult aspects of assembling (or building) a muscle bipe like an Ultimate was to install the wings and align them properly. The Wings Maker Ultimate 40 eliminates most of this work by using labeled cabanes and wing incidence templates.

    After first installing the center cabanes, using the labeled numbers and arrows for proper position, the top wing is held perfectly in place using the wing incidence templates. Not only are the top cabanes and wing incidence templates marked with arrows, so is the white center cabanes. If you hold them up to light, you can see the arrow construction in the wood marking the correct side to point up. These clever assembly techniques, combined with all the included hardware, make mounting the wings and cabanes a snap!

    The final step of assembly was to install the linkages for the upper ailerons. All the supplied hardware and pin holes in the ailerons made this step much easier.


    My Ultimate 40 was RTF at 90oz (5.6lbs) including the 18oz Lithium pack. I measured 60amps static current (or 1300 watts) with my AXI 4120/14 using an APC 11x7 e-prop. My 6-cell FlightPower EON28 3350mAh 28C pack can deliver 94amps continuous so it will not be getting stressed. My power to weight ratio was 1300w/5.5lbs = 232w/lb.

    The Ultimate 40 flew very well and the AXI 4120 provided enough power to knife edge at half-throttle. Full throttle was rarely used. We flew several flights with mixed aerobatics for around 7 minutes each. The only issue we had was with my old FMA digital servos lagging behind the pilot elevator control. I will replace them with new JR DS-821 digital servos.

    We saw no bad tendencies in flight and landings were relatively easy. The video of the Ultimate is with 10-15mph winds. We had plenty of power and the wind didn't really affect the flight. The combination smaller prop on a 6s Lithium pack really makes the Ultimate 40 nice and fast. As you can see in the video, my Ultimate 40 tore up the sky!

    Ultimate 40 Test Flights
    CLICK HERE (28meg)

    The Ultimate design is known as a "Muscle Bipe" because of its extreme aerobatic capability. They fly fast and land hot. The smaller span models under a 40" wingspan are the most difficult to handle usually due to high wingloading. In recent years, lighter construction techniques have allowed the 40" span bipes to become less of a handful to fly and land. The Wings Maker Ultimate 40 design is in this new category.

    Only intermediate flying skills are needed to handle this bipe as it is designed to fly very well and land slower with some low power required until touchdown. The key to a good flying aerobatic bipe is to have proper incidences and sufficient power. The Wings Maker light ARF design and incidence guides make the task a whole lot easier.

    Although a .40-size glow engine will provide sufficient power, a .50-size engine makes the Ultimate 40S very spirited! For a glow-to-electric conversion, having around 200 watts per pound provides great performance that is both clean and quiet. A motor in the 1000+ watt power class is recommended.

    1/4 Scale J3 Cub ARF

    The Wings Maker
    Distributed On-line at:
    2403 Research Drive
    Livermore CA 94550

    Hobby Lobby International, Inc
    5614 Franklin Pike Circle
    Brentwood, TN 37027 USA
    Toll Free: 1.866.933.5972
    Sales: 1-866-WE-FLY-RC (1-866-933-5972)
    Fax: 615-377-6948
    Web: www.hobby-lobby.com
    AXI 4120/14 Brushless Outrunner Motor

    ZAP Glues On-line at Frank Tiano Enterprises

    Zap Thin CA
    Pacer Z-42 Thread Locker
    5-minute Z-poxy
    Pacer POLY ZAP(tm)

    TOWER HOBBIES (Serving Hobbyists Since 1971)
    800-637-6050 or 217-398-3636

    FlightPower EVO25 3700mAh pack
    Higley (SPN108) 8mm x 1.0mm Safety Spinner Hub

    JR, and E-flite Products
    Distributed Exclusively in the U.S.A. by:
    Horizon Hobby, Inc
    4105 Fieldstone Road
    Champaign, IL 61822
    Ph: (800) 338-4639
    Toll Free: (800) 338-4639
    Fax: (217) 352-6799
    Website: www.horizonhobby.com
    E-flite 60-Amp Pro Brushless ESC

    FMA Direct
    5716A Industry Lane
    Frederick, MD 21704
    Website: www.fmadirect.com
    Sales: 800-343-2934 or 301-668-7614

    Maxx Products International, LLC.
    Tel: (847) 438-2233, Fax: (847) 438-2898
    Ordering Only Toll Free: (800) 416-MAXX (6299)

    MPI (6790) High current Arming Switch

    Comments on RCU Review: The Wings Maker Ultimate 40 E-conversion

    Posted by: PDARCS Flyer on 06/24/2009
    Hello Mr Covey,can you explain how you can charge your battery while still in the plane,as I like how you have built this model it has very clean lines.Maybe a diagram would help myself and others.thanks Steve
    Posted by: Greg Covey on 06/24/2009
    Hi, by using an MPI Arming Switch, the Battery is disconnected from the ESC when the arming pin is removed. In this manner, all you need is access to the charging balance connectors which can fit through a small hole near the cowl or fuselage bottom. By using a safe balancing charger, you can then properly recharge the pack while keeping it in the plane. The FMA Cellpro line of adapters also has an extension cable so that the plane can be several feet from the charger.
    Posted by: PDARCS Flyer on 06/26/2009
    Thanks greg for your reply ,it is much appreciated.cheers.
    Posted by: coddy on 07/03/2009
    Hi Greg, I have an E-flite Power 46 Brushless Outrunner Motor, 670Kv motor, E-flite 60-Amp Pro Brushless ESC and a 5 cell 5000mah lipo. Do you think i could use this setup in the Wings Maker Ultimate 40? Also, i read as well your 2006 review of World Models Ultimate and the two planes look to be very similar. How do they compare?
    Posted by: Greg Covey on 07/04/2009
    Hi coddy, The two planes are almost identical except for a slight change in the top wing incidence. My guess is that the new angle improves the alignment between the two wings. The Power 46 system should work fine. My only concern would be that your 5s 5AH pack may not fit properly. A smaller 4s 4AH pack would be better using a 11x7 prop. Good luck!
    Posted by: coddy on 07/04/2009
    Hi Greg, Thank you for your quick reply. I noticed that you used a 6s pack, and what i was not sure about with my setup was whether i would have the watts i would need. Wouldn't this be even more of a concern with a 4s 4AH pack?
    Posted by: Greg Covey on 07/04/2009
    You are right, coddy. I made a mistake as I was thinking about The Wings Maker Cub 48, not the Ultimate 40 which used a 6s 3350mAh pack. Your 5s 5AH pack may work fine as you will have less voltage drop from the larger cell capacity. I think it will be worth trying. Good luck!
    Page: 1
    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.

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