RCU Review: GWS Tiger Moth 400

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    Contributed by: Greg Covey | Published: May 2004 | Views: 96870 | email icon Email this Article | PDFpdf icon
    RCUniverse Review of the GWS Tiger Moth 400

    3401 Airport Drive
    Torrance, California 90505
    Telephone 310-891-3339
    Toll Free: 866-FLYGWS4
    Fax 310-891-3313

    See the Tiger Moth 400 in action

    Ease of Assembly
    Aerobatic ability

    Great scale looks
    Full-house controls
    Semi-symmetrical wings
    Plenty of power
    Excellent flight performance

    Manual errors

    The new GWS Tiger Moth 400 is a larger version of the popular GWS Tiger Moth slowflyer. It has a geared Speed 400 motor, real semi-symmetrical airfoil wings, and full-house controls for ailerons, elevator, and rudder. The heavier, more powerful Tiger Moth 400 can fly in light to moderate wind conditions.

    The kit comes complete with a geared GWS EPS-400C Speed 400 motor, mating GWS 10x6 prop, GWS clear foam-safe glue, and clay for balancing the model in flight. An optional GWS float set easily converts the Tiger Moth 400 into a water capable flyer!

    Length: 781 mm ( 30.7in)
    Wing Span: 960 mm ( 37.8 in)
    Wing Area: 27.4 dmĀ² (424.7 sq.in)
    Flying Weight: 500~550g (17.6~19.4 oz)
    Wing Loading: 18.25~20.1 g (6~6.6 oz)/sq.ft
    Power System: EPS-400C(D)
    Propeller: EP1060
    Battery Required: 8N730mAh(NI-MH)
    Servos: 3 PICO / NARO
    Receiver: R6NII
    Speed controller: ICS-400
    Radio Required: 4-Channel radio

    The GWS Tiger Moth parts are bagged in appropriate sections
    The foam wings have a semi-symmetrical design
    A colorful manual and decal set are included in the kit
    Shown above are the Tiger Moth 400 parts just removed from the box. I found no damage on any part and each of the various types of pieces were bagged in their own categories. The geared Speed 400 motor and 10x6 prop are included in the kit along with plenty of hardware and some clay for balancing the model.

    Initially, I discovered that the wings were a real semi-symmetrical airfoil and not just another undercamber design. I then discovered that this model had full-house controls for rudder, elevator, and ailerons! Lastly, I realized that the yellow paint did not come off easy or flake like on the film coating on the smaller slowflyer version. The parts could be handled without hurting the finish. I was immediately pleased with this new design.

    The kit comes with a full color manual and two decal sheets. The second decal sheet is various "GWS" cutouts.

    The manual has great photos and instructions that follow the text by number. I have found a tube length error and some orientation issues that I will cover later in the review. Overall, the photos in the manual were very helpful and only minor building experience is needed to follow them.
    GWS EPS-400C(D) Geared Speed 400 System
    ICS-300 Electronic Speed Control (ESC)
    The ESC came with an optional heatsink
    I received a GWS ICS-300J ESC with the review kit but suspect that it may not be the correct choice. The manual says to use an ICS-400 ESC. My ICS-300 ESC was rated for 8amps continuous and up to 15amps peak short term so I figured it was worth a try on my Speed 400 motor. Additionally, the ESC came with an optional heatsink that looked like a good idea to install. As it turned out, my ICS-300 ESC worked just fine.
    The ICS-300J ESC is modified for the supplied heatsink
    The heatsink is placed onto the thermal pad
    and then held in place with the new shrink wrap.
    The steps to install the heatsink started by removing the existing shrink wrap on the ESC because a new heatshrink piece is supplied to hold the heatsink in place and the plastic layer must not go in between the power transistor and thermal pad.

    Make sure that the protective layers are removed from both sides of the thermal pad and then place it directly onto the transistor. The heatsink can then be placed onto the pad and then held in place with the new shrink wrap. Make sure that after you heat the shrink wrap that the heatsink is held firmly against the thermal pad and the transistor. There should also be an opening for air flow at each end of the heatsink.

    The control rod tubing is first glued in place,
    and then the wing nut glued before assembling the fuselage.
    The fuselage is held together with rubber bands while drying
    Fuselage Assembly:

    The first step in assembly is to glue the elevator and rudder tubing into the sides of the fuselage tail. Although GWS supplies a tube of glue in the kit, I choose to use 5-minute epoxy just because it was a bit faster to dry.

    The manual says to cut the tube to a length of 260mm but this was rather short and did not agree with another photo farther along in the manual. I choose to cut my second tube at a length of 300mm.

    The above photo on the right shows the wing nut glued into place and you can see that my first 260mm tube is a bit short. It can actually go as far as being in-line with the wing nut.

    I then glued the fuselage together with Aileene's Tacky White Glue and held it with several rubber bands until dry. The supplied GWS glue work work fine here as well.
    The fiberglass rod support is glued into the bottom wing
    After cutting hinge slots with a razor knife,
    the ailerons are glued into the wing.
    Wing Assembly:

    The first step in the wing assembly is to glue a fiberglass rod support into the top side of the bottom wing. I used epoxy here but the GWS-supplied glue will also work fine.

    After cutting out the ailerons from the wing, you need to cut some slots for the hinges and drill holes for the torque rod. Now is a good time to paint the exposed white parts of foam back to Moth yellow. It can also be done fairly easy after the model has been test flown as I did.

    The aileron gap was set to match the torque rod
    Support plastics are glued into the wing and fuselage
    The wing is secured on both leading and trailing edges
    I used the GWS glue to attach the ailerons to the wings. Instead of cutting grooves into the aileron for the torque rod to sit in for a closer mate, I decided to leave the aileron out a bit to match the gap with the center part of the wing and allow less binding on the plastic hinge material. Either way should work fine.

    The next step is to glue some plastics into the wing and fuselage that will secure the wing on both leading and trailing edges. The landing gear support is also installed at this time.
    The wing is locked in place with a single screw
    A perfect seam is provided between the fuselage and wing
    The bottom wing mounts with just a single screw in the trailing edge and is locked in the leading edge with the double post. The wing to fuselage seam was a perfect fit on both top and bottom sides. It felt solidly locked into place.
    A metal joiner connects the elevator halves together
    The elevator is then connected to the horizonal stabilizer
    The supplied GWS glue worked great on the hinges
    Tail Assembly:

    The elevator halves are cut from the horizontal stabilizer and then attached together with a metal joiner. Again, paint the exposed white foam, if desired.

    Four hinges are used to hold the elevator to the stabilizer. I used epoxy for the metal joiner, and, after it dried, attached the hinges using the GWS glue.
    The rudder is first cut and then re-assembled onto the stabilizer
    A steerable tailwheel is attached to the rudder before mounting
    The finished tail sections are then glued to the fuselage
    The rudder is first cut and then re-assembled onto the vertical stabilizer in a similar manner. I added the steerable tailwheel assembly onto the rudder before attaching it to the fuselage per the instructions. I saw no issues with the stabilizer assembly and I am now ready to glue the tail together.
    The tailwheel support bracket is glued onto the fuselage bottom.
    Be sure to check the alignment of both stabilizers to the fuselage
    The tail assembly was quick and easy
    The horizontal stabilizer is glued in place first and then the vertical stabilizer. The rudder and tailwheel assembly is glued next and the final step is to glue the tailwheel support bracket onto the fuselage bottom.
    A large compartment has airflow from the front cowl opening
    The GWS EPS-400C gear motor simply pressed into place

    Motor, Wing Strut, and Cowl Mounting:

    Before installing the geared Speed 400 motor, I wired my ESC for a Dean's Ultra battery connector instead of the stock red JST connector.

    The motor simply pressed onto the pre-cut stick and was held securely with a screw through the plastic into the wood. I then epoxied the stick into the fuse slot. Everything fit together very well.

    Each strut is secured to the foam in a pre-formed pocket
    Strut and cowl supports are first sanded and then glued in place
    Tiny screws then secure the struts and cowl
    I started gluing my strut supports in place on the wing and fuselage. It is always best to rough up the plastic with sandpaper on the side to be glued. This provides a better hold.

    Missing cowl supports were made from scrap plastic and later found
    I simply cut 3 square pieces and glued them into place on the fuselage nose.
    The upper wing, cowl, and gear mains were installed
    The manual seemed to miss a step before mounting the cowl and the kit did not contain the parts needed. It went right into screwing the cowl in place on the fuselage. This was easily remedied by making my own square cowl supports from the leftover plastic strut support material. I simply cut 3 square pieces and glued them into place on the fuselage nose.

    After my building was completed, I think I found the plastic pieces meant for the cowl mounting in a separate plastic bag. There were these 4 white plastic pieces about the correct size in my leftover parts pile.

    After trimming the cowl and cutting out a hole for the prop shaft and another hole for airflow, I was ready to mount it to the fuselage with three tiny screws.

    I could now see that there was a plan for proper airflow into the front of the cowl through large openings in the fuselage to cool both the motor and ESC. This was a good design step by GWS for the TM 400.

    At this point, I decided to deviate from the manual step sequencing because the next step was to mount the lower wing which would block the inside compartment meant for installing the servos and receiver. Since I didn't want to unscrew the wing again, I decided to leave this step for last. When I did install the struts, you first glue the supports into both top and bottom wings. The struts are then attached with the tiny screws supplied in the kit.

    I installed the stock landing gear without issue. My Tiger Moth could now stand on all three wheels and I was ready to install the three servos and linkage.

    The components are placed in positions shown in the manual
    The linkages installed easily with "Z" bends on only one end
    Aileron control rods used "V" bends for fine tuning adjustment
    Servos and Linkage:

    I put the components exactly where the manual showed them. I used Hitec HS-55 servos which fit perfectly in the provided pockets. My GWS R4-P receiver has the full length antenna running through the inside of the fuselage.

    In the linkage photos above, everything installed easily and I only deviated slightly in some areas like not using "Z" bends on both ends of the aileron rods.
    My GWS Tiger Moth 400 was Ready-To-Fly at 14.1oz without battery
    The plane balanced perfectly without using any of the supplied clay
    A 3-cell Kokam 1500mAh Lithium pack provides a perfect fit and balance
    I measured the 10.5amp current draw to be within motor specifications
    A closer look at the 3-cell Kokam 1500 pack in my TM 400 reveals that not only a great fit after some slight carving under the dash, but the plane balanced perfectly with the stock GWS Speed 400 power system without adding any of the supplied clay. Alternatively, the Thunder Power 3-cell, 1300mAh Lithium pack is a bit lighter and will also work well with the GWS Speed 400 power system. Both Kokam and Thunder Power packs are available at Hobby Lobby.

    The recommended 7-cell, 730mAh NiMH pack has only limited power for the TM400. You'll see a huge power increase with a 3-cell Kokam 1500 pack. The Kokam 1500 cell can deliver up to 12amps continuous and the 730mAh NiMH cell only about 8amps. Additionally, the 3-cell Lithium pack provides the voltage of a 10-cell NiMH pack and therefore provides more power to the prop. I measured the 10.5amp current to be within motor specifications at full throttle for short periods using the 3-cell Lithium pack and stock prop.

    I also felt that a 7-cell NiMH pack provided too low of a voltage for this power system but an 8-cell, 720mAh, NiMH folded pack would work fine with the GWS Speed 400 power system. An 8-cell folded pack of 720mAh, NiMH cells also weighs about 4oz and can be purchased at Hobby Lobby.

    The Tiger Moth 400 can take-off from grass, pavement, or simply hand-tossed into the air. Novice R/C enthusiasts should solicit the help of an experienced pilot on the maiden voyage so it can be properly balanced, trimmed out and flight tested.

    The steep angle climb-out after take-off reveals plenty of power in the Tiger Moth 400

    We flew the Tiger Moth 400 twice today at lunchtime. Although the wind was changing directions and speed from 5-15mph, the plane flew great! I had plenty of power to handle the wind when needed and could throttle way down when it subsided. It flew inverted just as well with only a slight drop in lift from the semi-symmetrical airfoil.

    Slow rolls and giant loops are easily performed

    The roll rate was very scale and much slower than I have been used to with all my 3D plane flying lately. When rolling with rudder correction, it looked very scale in the air. Check out the video for some nice rolls!

    We took off from pavement and landed in grass several times without any sign of rollover. The structural design of the plane is solid and I didn't notice any problems under these rather rough conditions. GWS has elevated their original popular slowflyer design to an aerobatic parkflyer status!

    Flying low and slow across the field was made easy by the Tiger Moth 400

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