RCU Review: Hangar 9 F4U Corsair


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    Contributed by: Greg Covey | Published: April 2004 | Views: 106694 | email icon Email this Article | PDFpdf icon
    RCU Review Hangar 9 F4U Corsair Electric Conversion


    Review by: Greg Covey


    Distributed exclusively by:
    Horizon Hobby, Inc.
    4105 Fieldstone Rd.
    Champaign, IL 61822
    (800) 338-4639
    www.horizonhobby.com
    www.hangar-9.com


    Quality
    Completeness
    Performance
    Ease of Assembly
    Takeoffs
    Landings
    Aerobatic ability
    Appearance
    Manual

    • Excellent Flight Stability
    • Suburb Covering Scheme
    • Quality Strong gear mains and tailwheel
    • Excellent custom plastics and fiberglass parts
    • Great Documentation

    • Retracts need Adjusting

    Hangar 9’s ARF version of the famous F4U Corsair warbird legend is in a class by itself. It features all the usual Hangar 9® ARF amenities like top-quality balsa and ply construction, UltraCote® covering and all necessary hardware. It also includes pre-installed retracts that rotate 90 degrees as they tuck into the wings. Factor in the phenomenal flight performance and other scale touches like the pre-painted fiberglass cowl and authentic trim scheme and it’s easy to see why this is destined to be one of the most popular sport ARFs ever.

    The Corsair's most unique feature was the "bent" wing that resembled an inverted Seagull. This was the result of a marriage between the most powerful engine ever installed in a piston-engined fighter and one of the biggest propellers in the world. This gull-winged Navy fighter was so surprisingly powerful that it took months before anyone was able figure out how to land it on a carrier. It was the plane that won the air war in the Pacific.

    For more information and full scale specifications on the F4U Corsair, visit the Aviation History On-line Museum.



    Product: F4U Corsair .60 ARF
    Available from:
    Horizon Hobby
    Street Price:
    $264.99


    Wingspan:
    65.25 in (165.7 cm)
    Length:
    48.25 in (122.6 cm)
    Wing Area:
    752 sq. in (4851.6 sq. cm)
    Weight:
    7.5-8.5 LB (3.4-3.9 kg)
    Radio:
    5 channels w/ 6 servos (glow), 5 servo (electric)
    Recommended Engines:
    .61-.75 2-stroke; .91-1.00 4-stroke
    Required for completion:

    4 Hitec HS-85MG "Mighty Micro" servos for rudder and elevator
    1 Hitec HS-75BB Retract servo
    1 Hangar 9 1/7th scale US W.W.II Pilot (HAN8311)
    2 18" servo extensions
    1 servo "Y" adapter
    1 receiver


    As usual, I wouldn't get any glow fuel near a classic like this, so my e-conversion project will be using the new AXI 4130 direct drive brushless outrunner motor from Hobby Lobby.

    Kit Contents:
    All the parts in my Hangar 9 Corsair looked great! Each item was carefully packed in the box and arrived without any damage. After my success with their AT-6 model, I knew that I would not be disappointed with the F4U Corsair design!
    I couldn't have built a kit this well with my best efforts!
    The wings, fuselage, and tail all came in perfect condition. They needed no touchup with either an iron or heat gun. The cowl and canopy were precut and pre-painted. Later, in the review, I'll be cutting holes in the plastic mock radial head for air cooling. This is recommended for either electric or glow power.
    Unlike my Hangar 9 AT-6, the Corsair retract wells were not pre-installed. This allowed me to inspect the retract mechanism and apply some Locktite to the screws.
    Kit Quality:
    Some close up shots of the fuselage reveal the quality of construction and covering detail that has made me a real Hangar 9 fan! The fuselage, although light, was rock solid in strength.
    It seems that every part of the fuselage is rounded and sheeted with balsa before covering. The tail slots and motor mount holes are pre-cut. The canopy area is pre-finished and the cover pre-painted. Most of the decals have been pre-applied but an additional sheet comes with the kit to finish the scale appearance after the plane is built.

    Hobby-Lobby
    was my one-stop source for all my e-conversion parts. They had a wide selection of motors, props, connectors, batteries, and radio equipment to choose from.
    I selected all plug-n-play components for my e-conversion like the AXI 4130 motor, Graupner GR605360 6mm prop shaft adapter, and the Graupner GP315080 15x8, 3-blade prop. The prop, adapter, and motor shaft all fit together nicely!
    To keep my Hangar 9 Corsair light, I used some Hitec radio components from Hobby Lobby. My four HS-85 "Mighty Micro" metal gear, ball-bearing servos provide 49oz/in torque and weigh only .77oz or 1/2 the weight of a standard size Futaba S148 servo. That's a 3oz weight savings over standard servos.

    I also used an Ultimate BEC (or UBEC) and the Jeti ADVANCE 77-3P Opto-coupled ESC. The nice part about the Jeti ESC is that it comes with the mating connectors for the motor.
    It also has programmable timing modes and a brake on/off mode that i'll cover in detail later in the review.

    The UBEC is a state of the art switching regulator designed to convert an input voltage from 5.5v to 35v DC into a regulated output voltage of 5v to power your receiver and servos. The UBEC can deliver a continuous current of 3amps and a peak short term output up to 5amps. This is meant to handle power for up to 8 servos.

    A typical 4-cell receiver battery pack weighs 3.2oz so I saved 2.2oz along with the added convenience of not having to worry about re-charging another battery pack.


    Motor Mount:
    Here is the PM41001 Aluminum Motor Mount for AXI 41 Series Brushless Motors. This mount allows you to attach the motor on the outside of the firewall just like a glow engine mount. The three piece anodized aluminum mount is adjustable for lengths from 3-1/4 to 3-3/4". The front plate is pre-drilled for the large 41 series AXI motors. The lightweight yet strong mount comes with screws and nuts for attaching the front mount to the sides. It requires 4 bolts to attach to your firewall. I simply used the T-nuts and screws supplied in the Corsair kit that were meant to mount the glow engine brackets.

    To make the prop adapter extend to the correct 5-5/8" distance from the firewall to the cowl opening, you simply make two aluminum sheets that are 2" long. This extends the motor shaft to the proper position.

    I reversed the center screw set (supplied with the mount) so that the smaller head clears the rotating can.


    Power System Wiring:

    Before mounting the motor to the firewall, I wired everything up so it was plug-n-play once installed.

    Connectors supplied with the Jeti ESC are soldered onto the motor wires
    The wired power system is now "plug-n-play" ready to install into the plane
    My pre-wired motor mounted with ease using the stock T-nuts and
    screws that came with
    the Hangar 9 kit

    Aileron Servo Installation:
    The aileron servo mounts allow for almost any size servo

    The smaller size of the servo didn't matter with the mounting scheme used on the Corsair wing for the ailerons. I extended my servo cables using a 24" section of flat cable that I soldered myself. Alternatively, servo extension cables can also be purchased from Hobby Lobby Int. A little 5-minute epoxy held the supplied wooden blocks in place.

    Use the longest servo arm available so that the snap "keeper" doesn't bind

    Just when I thought it was perfect, I realized my servo arms were a touch short. I cut out a small slice in the balsa to allow the plastic keeper (not shown) to move just below the surface. Alternatively, you may wish to try a longer set of arms for the aileron setup than what is provided with the servo.


    Prop Mount and Painting:
    The Graupner 15x8 prop hole was opened just a little to allow the adapter to fit
    Painting the tips yellow adds a nice scale touch to the finished look

    Of course, I also had to paint the prop tips to match my rudder top. After noticing in several of my photos that I had painted the tips of my prop on the backside as well as the front, a fellow RCU scale enthusiast pointed out that only front side was painted on the full scale warbirds. Pilots found that looking at a yellow ring was quite distracting and fatiguing.


    Astro Flight Servo Tester:
    After struggling a bit with my retracts on my Hangar 9 AT-6 Texan, I finally got them the work great by bending the legs so that they were vertical when landing. This required a good deal of transmitter use and the receiver also needed to be powered by a battery.

    I decided that for my Hangar 9 Corsair, I would purchase an Astro Flight Servo Tester from Tower Hobbies for $20.

    It has been a great tool so far! I now use it on all my servos when testing the linkage and throw range.


    Retracts:

    The gear mains rotate 90° as they tuck into the wings

    The retracts on the Corsair rotate 90 degrees as they open and close. It was fun just to watch as I studied the mechanism and worked them manually from the control rod.

    They appeared to work fine and the one linkage piece that was nylon in my AT-6 retract linkage was now metal in my Corsair linkage. This made me happy because I felt it would make it more robust.

    Note that in the photos, you can see the string run through the wing for extracting the aileron servo leads. A nice design touch by Hangar 9. I choose to run the aileron servo wire extensions first before installing the wheel wells.

    The retract servo is mounted with parts supplied in the kit
    The retract servo mounting parts are layed out on top of the opening. I used a Hitec HS-75BB Retract Servo from Hobby Lobby since it was about half the cost of the JR version.

    Unlike the Hangar 9 AT-6 Texan where the wheel wells were preinstalled, they arrive open on the Corsair. I consider this a better approach because it allowed me to fully inspect the retract mechanism and route the aileron servo wires more easily.
    The rod position was moved to the outside bellcrank hole to increase travel
    We have discovered that even when using the longest servo arm on the HS-75BB Retract servo, the travel is not sufficient to lock the wheels in both directions.

    We moved the rod position on the belcrank from the inner hole to the outter hole by moving the quick link. In the photo, you can see the scored metal where the stock position of the quick link used to be.

    With the extra travel, we can now adjust the rod so that the mechanism pin goes all the way to the end when the wheels are out and almost all the way to the other end when the

    wheels are retracted. Always adjust the rod on the servo arm so that a full lock is obtained when the wheels are out.

    We also bent the rod going to the servo arm for a more favorable angle.

    Finally, a slight bend in the gear mains allows them to stand upright when extended and seat into the wells better.

    A perfect retracted fit
    in the well
    I found that by inserting a large Phillips screwdriver into the gear mains spring loop that I could easily bend the main gear rod so that it was perpendicular with the ground by forcing the wheel end over. This not only looked better but it provides greater strength to the gear mains when landing and made the wheels fully retract into the wells.

    I attached the wheel well with servo tape but you can alternatively glue it in place. The wheels were a perfect fit! I had fun testing the retracts for proper operation.

    Tail Section Assembly:

    Remember the elevator joiner before installing the horizontal stabilizer

    Before gluing the stabilizers into the fuselage, you need to remove the covering for a better hold.

    I choose to fit my entire elevator together on the table before installing the wire joiner in the fuselage. This ensured an easy assembly once the horizontal stabilizer was glued into position. After finishing my tail section, the Corsair really started to look great! The manual properly warns you about remembering to insert the elevator joiner before gluing the horizontal stabilizer, but, it fails to warn you about a critical rudder assembly step.
    Do not push the vertical fin all the way forward per the instructions!

    When mounting the vertical stabilizer, the manual instructions have you push it all the way forward. The instructions fail to tell you that this is only needed to initially install the tailwheel control rod for bending. Be sure to move the fin back until the rudder lines up with the tailwheel control rod for a bind-free fit.

    Note that in the photo, my tailwheel rod is not flush with the leading edge of the rudder since the fin is too far forward. Be sure to slide the fin only enough forward to provide proper alignment with the tail wheel wire (or support bracket) that is not yet installed.

    My assembly required some special cutting to help alleviate some of the binding since I did not push my vertical fin back into position after gluing. It should still work for a +- 30 swing until the binding becomes excessive.
    My completed tail assembly and orientation with the main wing
    My Corsair starts to shape up when the tail section is completed
    My Hangar 9 Corsair is starting to shape up! The wing is test fitted onto the fuselage and then used to help check the stabilizer alignment during assembly.

    Rudder/Elevator Servos:
    The smaller HS-85MG servos need additional bay extension pieces made
    The receiver antenna is run outside the fuselage through the rudder servo bay
    The rudder and elevator servos are mounted in the tail section in pre-made bays meant for standard size servos.

    To make my smaller HS-85MG servos fit, I created some small plywood pieces that extend one end of the bay and level the other end. Note that I also needed to extend my connector wires about 24" on both servos.

    I also used the rudder servo bay opening as an exit for my receiver antenna. No need to drill any extra holes in this beauty.

    Linkages:
    Installing the rudder swing arm set screw is key to a proper hold

    The rudder linkage assembled as easy as the elevator linkage. Since the rudder and tailwheel are turned by a swivel arm, it is important to file a flat spot on the rod where the set screw tightens and use some Locktite to keep it in place. The supplied snap keeper makes for an easy attachment to the servo arm.


    My receiver for this project is the FS5 from FMA Direct.

    The FS5, 5-channel Flight System receiver package represents the leading edge in safe, reliable radio controlled equipment. Equipped with new DSR technology and free Viewer Software, the FS5 receiver protects your aircraft during every phase of the flight!

    Combining unprecedented interference rejection, digital servo support, failsafe operation, radio data readout and other groundbreaking features in a small package, the affordable five channel FS5 works with the FM PPM transmitter you already have (or your PCM transmitter set to PPM mode).

    Exclusive Digital Signature Recognition (DSR) technology continuously guards against on-channel interference. In the event of signal loss or

    overwhelming interference,the FS5 instantly moves servos to their pre-set failsafe positions that are programmed using your transmitter and External Switch/LED (or Viewer Software).

    Before you take-off, the FS5 scans the airways and detects if someone else is on your frequency before you even turn on your transmitter. If there are interfering signals, the FS5 warns you with a bright LED light. This multi-function LED will also check battery voltage and inform you if signal loss was experienced during flight.

    While you fly, exclusive DSR technology continuously guards against interference. You just turn the receiver on and the DSR is automatic. It analyzes the data stream and automatically checks for:

    The 605SB servo buffer can be added in-line for each long wire run to the servo, if needed.
    • positive or negative shift
    • valid number of pulses (and stores this)
    • valid frame length
    • valid pulse widths

    After you land, the FS5 tells you how your radio system performed during flight. Each FS5 receiver includes free Viewer Software for extended, graphical data readout. While the Viewer Software isn't required for setting up the FS5, it is a great tool for radio system troubleshooting!

    In my setup, the ailerons are tied together with a "Y" adapter cable like Mitch suggested. You don't need independent aileron controls on the Corsair. I should also note that while the FS5 can mask interference issues, you still need to pay attention to such issues. After all, you don't want a situation where you are failsafing around the sky, right?

    FMA offers an excellent companion to receiver installation in situations where you are using long aileron extensions, etc. in an installation. The 605SB servo buffer can be added in-line for each long wire run to the servo. The addition of the FS5 Viewer software and Flight Recorder has given R/Cers the ability to troubleshoot installation and design issues we were never able to see before.

    First fly the FS5 with no buffers. When you land, look at the LED, if it's blinking, it will blink out the number of failsafe events you had during the flight. Don't turn power off or the memory will be cleared! Press the button on the FS5 3 times and it will then blink out the number of bad frames you had during a flight. The objective of course would be to install the buffers (at the receiver) until you minimize failsafe events (should be 0 if your radio is in good shape and tuned properly), and/or a low number of bad frames. This will provide you a very definitive picture of RF performance.

    The FS5 is actually an extremely precise glitch counter. Of course, if you have a real bad installation, you may get several failsafe events and you could run the counter on the bad frames to it's max which is 256. A clean flight should be somewhere in the neighborhood of 30 bad frames or less. It takes 50 consecutive bad frames to go into failsafe. Also, when you're counting bad frames, long blinks = 10 bad frames and short blinks = 1 bad frame. 10 long followed by 5 short would = 15.

    You might be surprised by how much you haven't been able to "see" before this technology!

    Hangar 9 1/7th scale US WWII Pilot (HAN8311) painted by Jaclyn Favro
    I was fortunate to have a rising young artist, Jaclyn Favro, from the Disney Studios in Orlando paint my WWII pilot figure for me. She used a scheme similar to my AT-6 pilot but added some additional detail for a great looking scale touch to my Corsair!

    A modified MaxCim Charging Harness uses Dean's Ultra Connectors

    Once again, I modified a MaxCim Charging Harness to use Dean's Ultra connectors, a 40-amp ATO-style fuse, and a single battery connection. My hope is that someday this type of charging harness will be sold to R/Cers for easy recharging of the battery packs in the plane. The ATO fuse moves from the 'Operate' to the 'Charge' position to connect the charge jack and disconnect the battery from the controller. This assembly allows me to mount my wing once in the morning of an R/C event and simply taxi into the pits for a recharge after a proper cooling period. It is a true convenience.

    Extra holes were drilled into the firewall to properly position the motor wires.
    The inside wiring is neat and spacious. Only the battery pack remains to be connected.
    I drilled some extra holes for the motor wires in a position that would not allow them to touch the spinning can and give me the maximum length.

    The motor plugs into the ESC and the ESC into the charging harness. The Ultimate BEC is then tapped into the battery connector to feed the receiver and servo 5v.

    Control Panel:
    My side wall control panel offers control and monitoring conveniences
    My control section outside the plane has a On/Off switch for the receiver 5v coming from the UBEC output and the FMA FS5 External Button/LED controls for monitoring interference and voltage level.

    The modified MaxCim Charging Harness has a charge jack and 2 positions for the ATO-style fuse; Operate and Charge.

    I have used this setup in several glow-to-electric conversions already and it provides the ultimate convenience.

    To touch up my exposed balsa from cutting holes, I discovered that the Delta Ceramcoat Acrylics (#2089) Navy Blue paint is a great color match for my Hangar 9 Corsair. The 16-color set was purchased at Michael's (SKU #02 957 5056 0599)

    ESC Timing Mode:
    The JETI Advance controllers are a great match for the AXI outrunner motors. When using the AXI outrunners like the 4130 on my Corsair, you can set the controller for Hard Timing mode. Hard timing increases both the motor RPMs and current draw by up to 20% over the default Soft Timing mode. Hard Timing is recommended for all Model Motor's AXI outrunner motors, even for the first flight.

    I also turn the BRAKE OFF on my JETI Advance controllers for all my aerobatic planes and scale warbirds. On scale warbirds, you do not want a sudden prop halt to jerk the plane into a possible stall situation. This also seems to always happen when the plane is downwind at low altitude. The free-running prop results in a more graceful drop in power level. More often than not, you can detect the power loss well before the motor is disabled.

    To program the JETI Advance controller, it is as simple as setting your transmitter throttle channel to full, turning it on, powering up the ESC and receiver, and listening for the appropriate beeps before setting the throttle stick to low. The new settings will not change after disconnecting the battery pack.

    In addition to automatic cutoff and programming of modes, the JETI Advance controllers have temperature overload protection which disables the motor when the temperature reaches 110 degrees C.
    Cowl Mounting:

    After cutting out the mock rotary engine, it was glued to the fiberglass cowl with epoxy.

    My finished cowl mounted on the fuselage with four screws into the supplied wooden blocks that were sanded and glued to the firewall. The motor fit perfectly behind the mock rotary engine and the cutouts supplied plenty of fresh air for cooling the motor.


    Canopy Mounting:
    I decided to install my pilot after the maiden flight so instead of gluing on the canopy, I made it removable with Du-bro (#525) #2 x 3/8 Button Head Sheet Metal screws.

    Balancing:

    Initially, my plane balanced at 4" from the leading edge (LE) until I adjusted my flight pack

    My Corsair initially balanced at 4" behind the leading edge (LE) with the 18 cells in two packs behind the firewall. The proper starting balance point is 5" behind the LE at the fuselage. I made a 2" adjustment to my flight pack to "zero in" the CG.

    To aid in balancing my .60-size Corsair, I used the Great Planes CG Machine. Note that the plane should be balanced with the gear mains retracted as in normal flight conditions.


    Battery Positioning:

    A "Y" adapter allows two battery packs to be connected in series

    I created a "Y" adapter from Dean's Ultra plugs to connect my 10-cell pack and 8-cell pack together in series. This makes it easy to upgrade to a single Lithium pack at a later date.

    My two packs were taped together using duct tape. The packs fit perfectly in a position under the receiver tray so that only a few pieces of foam were needed to hold them in place. I wrapped foam on the forward side of the plywood former so that a hole was left in the middle for the two packs.

    Although the packs were held well by the foam wedged into the sides, I also wrapped the connector wire from one pack around the plywood receiver tray for additional security. The Dean's connector was then held with a tywrap.

    The battery position shown for the 18-cells of CP2400SCR will put the CG properly at 5" behind the leading edge at the fuselage.

    My finished F4U Corsair is shown with the retracts up and down

    My finished Corsair weights 152oz (9.5 lbs) RTF with 18-cells of CP2400SCR.
    I set the control surfaces to the throws recommended in the manual. (±11° for ailerons and elevator, ±20° for rudder)


    The Corsair was finally ready to fly after passing the pre-flight check

    My Corsair was ready to fly after fine tuning the retract linkage a bit. The controls checked out, the throw range was good, the power checked out and the prop ring told us that it was go time!

    The prop ring told us that it was go time!

    The Corsair started down the runway with authority and the heavy cross wind required full right rudder to keep it on track. The tail had already lifted when it passed me so my pilot, Lynn, pointed it slightly into the wind for liftoff.

    When the Corsair sped away into the sky, we silently watched it in awe

    The realistic look of the Hangar 9 design was evident in the bright sunlight

    The Corsair seemed to handle the wind very well. The long wing chord provided enough lift to make it feel lighter in flight than was expected at 9.5lbs.