RCU Review: Kangke Monocoupe ARF

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    Contributed by: Lynn Bowerman | Published: December 2004 | Views: 68776 | email icon Email this Article | PDFpdf icon
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    Manufacture: Kangke Industrial Inc.
    Model: Monocoupe 90A
    Scale: 1/5
    Price: $ 299.77
    Wing Span: 76”
    Wing Area: 865 sq in
    Length: 52”
    Actual Flying Weight: 9lbs 14 oz
    Engine Used: SK80AR .80
    Prop: APC 14x8
    Radio Used: JR XF 783
    Channels: 5 Channels used
    Servos: 7 Hitec HS-475,
    Construction: Plywood & Balsa Built up
    Ease of assembly
    • Fiberglass cowl & wheel pants
    • Flawless covering
    • Fast building
    • Thorough Manual
    • Good Stall characteristics
    • Very scale appearance
    • Everything Fit Perfectly
    • Some minor hardware had to be replaced.
    • Bolts for wheels needed to be longer.
    The Monocoupe 90A was the first two placed cabin airplane. The Mono Aircraft Corporation in Moline, Illinois manufactured it until late 1931. The company was moved and reorganized to a new location in Lambert Field, Missouri and renamed the Monocoupe Corporation. Monocoupes were produced up untill the early 1950s. In the early years, they were produced as three different models, the 60,90, and 110. They were promoted as economical, easy to fly trainers with the exception of the 110. It was the most successful certified aircraft for racing in the Golden Age of Air Racing. Super Kraft is producing the Monocoupe 90A in a 1\5 scale version.
    Kit Contents
    Main Components
    Hardware Packages

    Main Components Hardware Packages
    The Monocoupe came in one big box. Everything in the box was in perfect condition. All hardware was complete What first caught my attention was the size of the wheels. They are large and will work very well on grass fields. I see this as a definite plus. The other pieces of hardware that are worth mentioning are the beautifully made aluminum control horns as they are very simple to install. All you need to finish the Monocoupe is some fuel line, radio gear and engine.

    Wing Assembly

    Wing, Flaps, Ailerons Servo Bay Openings

    Super Kraft has designed the wing so that the modeler has two options when assembling. You can either leave the full strip aileron the way it is, or cut it for flaps. I decided to cut the flap section out.

    Aileron & Flap

    When cutting the flap section out you will measure from the inboard end 13 ½ inches. Use a straight edge and a sharp exacto knife; it will take several cuts to get through aileron. After you have cut the flap from the aileron you will need to put some covering on the ends that have bare wood showing. In the box you will find the two square pieces of covering to do that with. Now go ahead and test fit both ailerons & flaps. If satisfied with fit, go ahead and glue hinges and controlling surfaces in place.

    Gap Sealing

    Ironing Gap Seal

    After gluing all the controlling surfaces on the wing, you are ready to seal the gaps. In the box you will find two long strips of covering, use these for your gap seals. Follow the instruction manual closely when installing gap seals, as there are certain steps that you have to take to make them come out right. This step takes a little time but it’s worth it You get a real clean looking hinge line and it makes your controlling surfaces work more efficiently.

    Wing Servos

    Aileron Servo Flap Servo

    The aileron servo bay will already be opened and ready for the servo to be installed. The flap servo bay will not be opened. If you choose to use flaps you will need to remove the covering from the servo bay. Once the covering is removed you can install the flap servo the same way as the aileron servo. Taped inside the wing there will be a string for pulling the servo wires.

    Flap Linkage
    Aileron Linkage
    Flap Control Rod

    Read the instruction manual carefully when making the flap & aileron linkages, they cover this part in good detail. In the Flap Linkage photo, the flap is in the up position. By setting up the servo this way the flap will end up in the exact position every time. When setting up the flap lay a straight edge on the bottom of the wing and adjust the flap until it touches the straight edge

    Aileron linkage setup
    One of the characteristics of a high wing airplane is the need for using rudder to help maintain turns. Super Kraft gives you two options on how you can set up the ailerons to help the monocoupe turn easier. When turning the outside aileron goes down, and, it creates more lift which raises the wing. This also creates drag which causes adverse yaw. That’s why rudder is needed in turning. The way to help this problem is to use Aileron Differential, meaning that the ailerons go up more than down.

    The instruction manual explains two ways that you can accomplish this. One way is to use a programmable transmitter on two channels and program the differential in, or, you can use a Y-harness on one channel and set up the servo. I’m going to show you how to set up the servo and use a Y-harness. On the picture Aileron Linkage you will see that the linkage is above center. This causes the control linkage to move in one direction more than another.

    Take some time setting this up and you will be able to get the required throws.

    Wing Struts

    Lower Strut Mount
    Upper Strut Mount

    SK designed the wings to be held by an aluminum tube, so they can be easily removed for transporting. This is a very nice feature. Because of the aluminum tube holding the wing, the struts are functional. They are already made and nicely painted. All you have to do is install the clevises on the upper strut end and adjust them. They look very nice and are very strong.

    Landing Gear

    Main Gear Mounting
    Tail Wheel Mounting
    Tail Wheel
    Tail Wheel Linkage

    Installing Landing Gear
    Super Kraft includes all landing gear and hardware needed for the monocoupe. The main landing gear is nicely painted. The T-nuts are already installed in the fuselage; you simply get the hardware for the main landing gear and bolt into place. When installing the tail wheel, make sure that you have already installed the tail wire bracket. You will be using it as a guide to locate tail wheel position. Slide the tail wheel assembly as far back as possible without interfering with tail wire bracket. Once you found the tail wheel location, drill your mounting holes and carefully put some thin CA in the pre drilled holes. This will put some added strength to the wood in your holes. You will need to install your rudder to finish the tail wheel installation. After the rudder is installed, you can now mount the tail wheel springs bracket. The bracket should be mounted 2 inches from the hinge line this will set the correct spring tension. I found the tail wheel assembly very easy to mount and simple to get aligned.

    Wheel Pants

    Wheel Pant
    Wheel Pant Inner

    Installing Wheels & Wheel Pants
    As a suggestion, make this process one of your last steps to finishing, the assembly. Without having the wheels on the plane, it stays still for you on the bench and makes assembly much easier. The assembly of the wheels and wheel pants is very simple. A bolt is used for the axle. The instruction manual shows you a picture of the sequence on how all the parts go together. The wheel pants are held on by the axle and another screw above the axle. This assembly works very well. Be sure to use a little a loctite on the axle bolt. After several flights I had one of the axles come loose. The axle bolt needs to be a little longer but works fine. The big wheels work very well on grass runways.

    Cowling & Engine Installation

    Cowl and Sub Cowl
    Cowl on Sub Cowl
    Cowl Length

    Cowl Installation
    When installing the cowl and sub cowl, make sure you pay close attention to the measurements in the instruction manual. These measurements are important. If you follow them your correctly, you will have no issues with engine to cowl length. One nice feature when you use the recommended engine and muffler combination is that you will not have to modify the cowling. The instruction manual covers the sub- cowling procedure thoroughly and everything fits very nicely.

    Engine Mounting

    Engine Mount
    Engine Mounted
    Engine & Sub Cowl
    Engine Mount Completed
    Muffler Mounted

    The engine mount supplied in the kit is made of aluminum. You will have to drill the holes in the mount for your particular engine. The holes for the firewall mounting are already there. When mounting the engine, follow the instruction manual closely. There are measurements that you will need to use in order to find the center of the firewall. After you have mounted your engine, you will now need to modify the sub cowl. If you use the recommended SK80 engine, you can follow the instruction manual for the modifications. If you choose your own engine, make sure you leave large enough openings to allow cooling air to pass through. One thing that I recommend, after doing the sub cowl modifications is to make sure you fuel proof the bare wood.


    Engine Box Front
    Engine Box Side
    Muffler in Package

    The engine used for the review is a relatively new line of engines called SK engines. The particular engine used for the review is the SK80A/R {Item No.KE051}. The SK80 is a .80 two stroke. It has dual ball bearings, ABC construction and it uses SK’s own high performance carburetor. The SK 80 also comes with a muffler and two year warranty. The pitts muffler that I used in the review is the one recommended by SK, {No. KP006}. One thing that I noticed when inspecting the muffler is that it comes with a metal gasket not a fiber type gasket like most. I’ve had no problems with any loosening of the muffler after many flights.

    Engine break in and Performance
    The SK80 is a very impressive engine. The first time I started the engine, I primed it like normal, hooked up the glow starter and on the first flip it was running. After one tank of fuel the engine it was idling very reliably and I felt that it was ready to flown. I used the recommended 13x6 prop during the first run in and a 14x8 for flying. The SK80 turns the APC 14x8 prop at 9000 rpm’s, even with the engine not completely broke in. After many flights the SK80 has proven to be very reliable and easy to start.

    Fuel Tank Installation & Set up

    Fuel Tank & Parts

    Before installing the fuel tank, you must decide if you’re going to use a two-line fuel system or three line. If you decide to use a two-line system you will have to disconnect the fuel-line off the carburetor every time you need to fill or empty the tank. With a three-line system you can have a separate line for filling and emptying this works very nicely. SK supplies all the materials to be able to make the three-line system. When installing the tank make sure that your motor mount bolts aren’t sticking too far out of the firewall. If so, they could puncture a hole in the tank over time. The fuel tank installation is very easy. Just follow the instruction manual and you will have no problems. One nice feature with the tank installation is the tank stopper protrudes through the firewall leaving all fuel lines visible from the front.

    Installing Fin & Rudder, Stab & Elevators

    Stab With Covering Removed
    Tail With Hinges
    Tail Side View
    Tail Right Front

    Installing the tail parts was very easy; they aligned perfectly and took very little time. One word of caution when you are removing the covering from the horizontal stab, be careful that you don’t remove any covering in an open area. Refer to picture, “Stab With Covering Removed”, you will see my black lines showing fuselage outline and then the actual covering that was removed. The remaining covering on the inside of my black lines is open underneath. When you are ready to install the horizontal stab the instruction manual explains an easy way to align the stab. By first finding the center of the fuselage over the cabin area and using a pin with a string to swing back and forth from tip to tip. This makes it very easy to square the stab to the fuselage without doing any measuring. One nice feature by SK was putting holes in the center of the stab for using screws to hold it in place while the glue dries. I used Elmer’s Pro Bond for installing the horizontal stab and fin. The Elevators and Rudder fit very nicely. SK supplied CA hinges, all hinge slots lined up and installation took very little time. I found the whole tail installation to be a complete pleasure with no difficulties at all.

    Tail Bracing

    Tail Wire Connector
    Tail Bracing & Controls

    Note: the tail wire bracing is functional, and plane should not be flown without them. SK supplies all needed tail bracing hardware. Tail bracing rods are already made to size and will only fit in proper locations. Follow the instruction manual for tail wire connector locations. SK has already put the mounting holes in the tail for you and you will have to remove the covering over them. Be careful when installing bracing, don’t make them too tight or you could distort the shape of the tail.

    Control Horns

    Tail Control Horn
    Control Horn

    The control horns supplied with the Monocoupe are beautifully made of aluminum. They are easy to install, you will only need to drill a single hole for them. One note that needs mentioning before you start installing them is to make sure that you separate the control horns for the ailerons. They will have longer screws in them. The ailerons are thicker than the tail parts. The instruction manual gives you all the measurements for proper location of the control horns and they work very well.

    Pushrods & Servo Installation

    Servo tray
    Throttle Linkage
    Throttle Servo
    Pushrod Support

    Servo Installation
    The servo installation is very easy. You install all the servos on the servo tray before putting it in the plane. The servo tray mounts are already installed in the fuselage. The servo tray is screwed to the mounts by four supplied screws. Make sure that you refer to manual for correct servo location. The rudder servo goes in the middle and upside down. SK supplies with the plane all hardware for the rudder pull pull system. You will be able to install the pull-pull system with the plane upside down and the bottom hatch removed. There are good illustrations for building the pull-pull system in the instruction manual.

    Elevator pushrod assembling, you will have to assemble the elevator pushrod. It is very important to use the measurements in the instruction manual. Because with the servo tray already installed in the fuselage the pushrod lengths are critical and you need to build them correctly the first time. I added an elevator pushrod support in the rear of the fuselage. The extra support is something that I like to do but probably not necessary. I added a photo showing the extra support for reference.

    Radio set up

    The radio I chose is the JR Xp 783. I felt that it would be a good combination for the Monocoupe.The receiver battery is a 650-mah 4-cell pack. I wrapped the battery and receiver in foam and installed them where the instruction manual recommended. I then ran the antenna out the bottom of the fuselage. All control throws were set according to the manual. The rudder is 1.25” each direction from center. Elevator is 3/4” up & down from center. Ailerons are 3/4”up & 3/8 down from center and flaps are 1.0” down for landing & 1/2" for take off. I have not had to make any changes from these settings since flown. I do recommend that you use exponential for the rudder.

    Take Offs

    On take offs you apply a little up elevator. Advance the throttle to full and be ready for any rudder corrections that might be necessary. The rudder on the Monocoupe has real good authority, so be careful not to over correct. Once the Monocoupe gets enough airspeed it will gently lift itself off the ground.
    It took me several take offs before I got smooth with them.


    The Monocoupe lands very nicely, I’ve landed it with and without flaps. When using the flaps you will notice that the Monocoupe will want to pitch its nose up, this is normal. You can either use some trim on your transmitter to get the nose down or mix some down elevator in with the flaps. When landing without flaps, the Monocoupe will want to come in a little quicker, but, when flaring, it will nicely bleed off the speed. Even with the Monocoupe being a nine pound plane, it lands like it’s much lighter.

    The monocoupe really flies like a full-scale plane. For example, when you are making a turn, you use aileron and rudder together to start your turn then just rudder alone to hold the turn. Then opposite aileron and rudder together to level. The rudder has good authority and the Monocoupe could be flown without the use of ailerons. These are the same characteristics as a full scale. I found that the Monocoupe flies well at all speeds. I didn’t notice any control feel difference at slower speeds. The recommended SK 80 engine provides plenty of power. You can do nice big loops, slow rolls and gentle stall turns. One note needing mention was on the first few flights the Monocoupe yawed to the left. After some investigating it was found that vertical fin had a slight twist in it. The fix for this was to carefully twist the fin straight and re shrink the covering, after doing this the Monocoupe flew perfectly.

    Weight & Balance
    Sk recommends that the balance be somewhere between 22% - 29% of the wing chord. This means the balance point will be between 2 ½”- 3 ¼” back from the leading edge. This particular Monocoupe came in at 3” back from the leading edge with no weight added for balance. Much to my surprise, I thought that the Monocoupe was going to fly a little tail heavy but it didn’t. The recommended balance point was just fine.

    The Monocoupe is a lot of airplane for the money. With a wingspan of 76”and a length of 52”, the round nose on the fuselage makes it a large airplane. Not only does it look scale but flies scale as well. The Monocoupe will do all basic aerobatic maneuvers as well as fly gentle for some relaxing flying. Another nice feature is the option to add flaps if you should decide, with previsions inside the wing for the flap servo all ready there. If you should decide to use the recommended engine & muffler combination. I’m sure the performance will be to your liking.
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