Model Aero Polaris Model Aero Aqua Cat, Aqua Cat SE, and Aqua Jet Build Guide Note: Aqua Cat SE and Aqua Jet specific instructions are at the end of the build guide. Some photos may depict the Polaris kit. In these cases the build is identical to the Aqua Cat Specifications: Wingspan 36.0" Length 41.0" AUW 17-22 oz. Wing area-306 sq. in. Wing loading-8.8 oz./sq. ft. Motor-Spin Max 2212-6 or equivalent ESC-40-50 amp Prop APC 6/4E Battery-1300 to 2200 3 cell lipo Controls-Ailerons, elevator, rudder, throttle Requires 3 micro servos (9 gram)
Introduction The Model Aero Aqua Cat combines the versatility of our Polaris Seaplane and the superb flying qualities of the AeroCat. This Hybrid design results in a fast, stable aircraft that can fly off water, grass, or snow! Like the Polaris, it features simple sheet foam construction and excellent handling qualities, both in the air and on the water. In flight this model is smooth and stable, yet also very aerobatic. On the water it tracks straight as an arrow and takes off and lands effortlessly. But one of the best things about this model is the amazing speed range-with the recommended power setup the top speed approaches 70 mph, yet the model slows down extremely well. This allows the model to be flown in very tight spaces if desired, or if you have a bigger flying site you can open it up and enjoy the speed. It handles wind and waves remarkably well, too. This model also flies very well off of grass or snow-takeoffs require only 10-20 feet and it can even taxi and do easy touch and goes off of grass. Recommended motor setups include: The Aqua Cat was designed to use a high kv brushless outrunner motor spinning a 6" or 7" diameter prop. Recommended motor setups include: Spin Max (Suppo) 2212-06 motor (recommended), 1800 to 2200 mah 11.1V lipo battery, 40 amp ESC with heat sink, APC 6x4E prop Spin Max (Suppo) 2212-10 motor, 1300 to 2200 mah 11.1V lipo battery, 30/40 amp ESC with heat sink, APC 7x5E prop Additional Items Required Glue (Foam safe CA/accelerator, epoxy, 3M77 spray, Foam Tac, or the glue of your choice) Hinge tape-blenderm or Scotch Transparent tape 3 pieces of 16 gauge wire 18 to 20 long for motor wire extensions 1 servo wire extension for the elevator servo (12 ) Power system: motor, ESC, battery, heat sink (optional but recommended) Motor/ESC connectors as required 3 servos (minimum torque 17 oz-in) Most 9-12 gram servos meet this requirement Construction It is recommended that you read through the construction guide completely and study all the pictures carefully before you begin building. Note that some photos may be of the Polaris kit. In these cases the build is identical to the Aqua Cat. Note that some photos may be different than your kit. For example, we have incorporated some tabs and notches in the wing and fuselage that are not shown in some of the photos. Additionally, some construction photos show decals already on the plane. You may find it easier to apply some of the decals such as the wing and tail during assembly, rather than after the plane is built.
In this photo, we ve assembled the main wing panels and glued all the carbon spars into their respective slots. If using epoxy, scuff the carbon with some fine sand paper before gluing it in. After the glue is fully cured, we have found that putting a strip of Scotch Transparent tape on each side of the carbon pieces really helps stabilize the joint. You may now bevel & hinge the control surfaces using your preferred method. We use simple tape hinges as shown above. The red lines indicate Scotch Transparent tape or Blenderm tape. It s important that the foam be very clean prior to applying the tape. A tack rag or a piece of tape put down and then peeled off works well to clean the foam of dust. We recommend CA hinges or small nylon hinges for the rudder.
Next, apply the fuselage reinforcement strips to the edges of the fuselage. Be sure to make a left and right side! Leave a 6mm gap next to the fuselage step to allow for the rear fuselage former. Foam Tac3M77 Spray Adhesive works well here. After the strips are attached, trim them off flush with the front of the fuselage.
2 Photo above shows the three fuselage formers in place. The middle former should be positioned 2 back from the front of the wing slot. Photo at left shows the bottom of the fuselage, with a small strip of foam glued to the aft side of the rear former. This piece will help support the aft fuselage bottom piece.
Photo shows the fuselage bottom glued into place. Once the glue is dry, sand the edges flush with the fuselage sides. Leave the corners fairly sharp as this will improve water tracking. Now is a good time to seal the inside of the fuselage. We run a bead of glue or latex caulk around the inside of the fuselage. Photo above shows the wing slid into the fuselage slots (Polaris shown, Aqua Cat assembles the same). Carefully fit all the tabs into their respective notches. Note that the battery tray (inset photo) has also been installed. Some sanding of the battery tray may be required to get a perfect fit.
Before starting assembly on the vertical stab and nacelle, study the text and pictures carefully to make sure you have a full understanding of the assembly procedure. The vertical stab inner core parts are shown above. The rudder, at right, will be installed later. Photo above shows vertical stab inner core pieces laid on top of the outer vertical stab piece. The space between the pieces forms a wiring channel for the motor wires and elevator servo extension. Mark the channel with a pen, then tape off the channel prior to gluing. Keeping glue out of the channel will ease running the wires later.
Photo above shows the two outer vertical stab pieces glued to the inner core pieces. Next, sand the leading and trailing edges of the vertical stab to a pleasing rounded shape.
The nacelle bottom is shown attached to the vertical stab. Next, sand a bevel on one end of the nacelle side pieces as shown.
Carefully bend a curve in the nacelle sides to match the nacelle bottom. Using heat from a heat gun or hairdryer will allow the foam to be bent easier. You can practice this technique on some scrap foam. Once the nacelle sides are shaped and attached, glue the foam firewall and wood motor mount in place using epoxy. It is also recommended that you coat the inside of the foam firewall and surrounding area with epoxy for reinforcement. Note that we have painted the motor mount black as we do all of the wood pieces. It s not necessary; we just think it looks better. The rudder may be attached at this time.
Shown above are three 18 to 20 motor wire extensions (not included). Note we have put bullet connectors on each end which are not necessary but ease the hookup of the motor and ESC. The wire should be 16 gauge. The motor has been installed, and the motor wire extensions and elevator servo wire are shown exiting the vertical stab. We have applied the decals since it is a little easier at this stage of the build (Polaris shown, Aqua Cat assembly is identical).
There is a lot to see in this photo so study it carefully. Note that the wood vertical tail base support has been installed (painted black). Then glue the entire vertical stab/nacelle assembly into place. Note the small piece of foam that functions as a servo support. The wire elevator pushrod is shown exiting the nacelle. Once you are satisfied with the operation of the elevator servo, attach the horizontal stab and top fin. Don t forget the screw for the servo arm! Photo above shows the pushrod setup for the ailerons and rudder. Simply slide the shrink tube over the rigid guide tube, then insert the wire through the tube and shrink the tube around the wire. This creates a near watertight seal. A dab of Vaseline where the wire exits the shrink tube will help seal it even better.
½ This photo shows the aileron and rudder servos installed through a small foam doubler (inset photo). Note that holes for the servos are not precut, and the aileron servo should be installed about ½ from the rear fuselage former. The pushrods are in place. Carefully calculate the angle between the servo arms and control horns and bore an angled hole in the fuselage sides for the pushrod guide tubes. It is recommended that you use some type of adjustable connector such as a Dubro Mini EZ Connector either on the servo arm or control horn. Also visible are the motor extension wires and the elevator servo wire. The wires are routed up through the wing as shown. Once you are satisfied with the servo and linkage operation, you may glue or tape the bottom aft fuselage cover on. Often we simply tape this piece on prior to performing a grass maiden flight. For water flying, it is best to glue it on and take steps to be sure it is sealed.
Photo above (top of plane) shows the motor extension wires coming up through the wing and attached to the ESC. We recommend you not extend the battery wires of the ESC as it can cause damage to the ESC. The location of the RX and ESC may vary depending on the type of gear you are using. For example, if using 72 MHz radio gear, you would want to isolate the RX from the motor wires as much as possible to avoid interference. This does not seem to be an issue with 2.4 GHz gear. The heat sink is shown attached to the ESC. A hole will be cut in the fuselage top to expose the heat sink to outside air. Photo at left shows the heat sink after installation through the top of the fuselage (Polaris shown, Aqua Cat is the same). If you choose not to use a heat sink, make sure there is adequate airflow over the ESC. Small air scoops can be made from plastic spoons, with one facing forward ahead of the ESC, and one facing to the rear behind the ESC.
Photo above shows the hatch arrangement we have used on the last few builds. Use strips of thin ply or foam at each end and simply flex the hatch into place. The location of the hatch may vary depending on the motor and battery used. Since Installing the hatch is one of last steps of the build, you can position the battery to achieve the required CG, then cut the hatch accordingly. A couple magnets in the center of the hatch can be used for additional security. 6 13 3 ½ The above dimensions were used on our latest build, using a 2212-6 motor and 2200 3S battery. The removable center hatch is large enough to provide easy access to all the electronics.
Photo at left shows the tip floats and nose pieces laminated using Foam Tac or 3M77 spray adhesive. There are 5 pieces for each tip float and 9 pieces for the nose. Sand the tip floats smooth and attach them flush with the wing tip. On the Aqua Cat we usually sand off the small nubs on the top of the tip floats. Round off the nose pieces to a pleasing shape and attach. We have painted ours black using a water based craft paint brushed on with a small foam brush.
Congratulations!!! That completes the construction of the Aqua Cat. See below for setup tips and decal application tips. Setup and Flying Note: The Aqua Cat is designed for intermediate and above pilots and is not recommended as a trainer or beginner plane. It should be operated in accordance with AMA guidelines. Adjust the flight controls to provide the following recommended deflections (all measured at the root trailing edge): High rates: Elevator:.75 each way (40% exponential) Ailerons:.65 each way (40% exponential) Rudder: 1.25 (25% exponential) Low rates: 70% of the above settings. Note: We recommend low rates for the first flights until you are familiar with the plane. If using a radio without expo or dual rates, we suggest about 55-60% of the high rate throws shown above for aileron, 70% for elevator, and about 1 each way for rudder. CG: The recommended CG location is on the fuselage step or up to ¼ ahead of it. To take off just add throttle and slight back pressure on the stick, and the model will leap off the water in about 10 ft. Or you can bring the throttle up slowly and fly it off the water gracefully. You ll find this model is smooth and well-mannered in the air, with no bad habits. But it's also capable of excellent aerobatics!
Decal Application Decal application procedure is the same for all kits. Reference Polaris photos for decal placement. Note: The decals for the Aqua Cat SE may not have backer paper. In this case carefully peel and stick the decals. Before applying the decals, clean the foam of sanding dust. An effective way to do this is with a tack rag or packing tape. Laying the tape down and peeling it off removes all the dust from the foam, allowing the decal to stick better. Trim each decal as shown in photo, leaving 1/16 to 1/8 of the backer paper around the decal. Then, peel the decal/backer from the sheet & place the decal in the desired location and press down thoroughly. Very carefully peel the backer paper off the decal, making sure the decal stays on the plane. If the decal lifts off the plane, just press it back down and try another corner. Tweezers work very well for grabbing the backer paper. Additionally, a bit of Windex or water applied to the backer paper will soften it and ease it's release. Just be sure not to get any moisture under the decal itself.
Model Aero Aqua Jet The Aqua Jet, like the Aqua Cat and Polaris, offers superb flying qualities and unmatched versatility, capable of flying off water, grass, or snow. However, the EDF power system takes the excitement to a whole new level. The Aqua Jet is simply exhilarating to fly, especially with the RC Lander 68 mm EDF. These fans have a fantastic sound and great power. When you taxi this plane out to fly at your local field or lake, prepare to be the center of attention, as all eyes will be on you! The Aqua Cat and Aqua Jet are very similar builds. If building the Aqua Jet (EDF version), follow the steps below to complete your airplane. The key differences are: Vertical stab Elevator servo and linkage Wing braces Power system The Aqua Jet is designed to use the RC Lander 10 blade 68 mm EDF unit in 3S configuration (4300 kv). However, other EDF power systems can be fitted. We recommend staying with a 3S setup due to weight. We re flying ours with an AGA Power 2600 3S 50C battery and 70 amp ESC with exposed heatsink. The AUW on our plane is 28 oz. and the thrust is approximately 40 oz.
The photo above shows the wing braces, EDF mount, 6 mm vertical stab center piece, 3 mm vertical stab outer pieces, and the elevator pushrod guide tube. Photo at right shows the vertical stab center piece laminated to the vertical stab left side, as well as the placement of the pushrod guide tube. Photo at left shows the vertical stab right side piece attached. The completed assembly has been sanded to a pleasing rounded shape, and the rudder has been cut free, then beveled and hinged into place. CA or nylon hinges may be used.
This photo shows the wing braces epoxied to the bottom of the wing. We chose to paint all the wood pieces black. Also note the tip floats have been laminated and glued into place. Note that the tip float isn t flush with the edge of the wing. It should be flush. This photo shows the EDF mounting rails attached to the top of the plane. The spacing is 3 9/16 as shown. Screws are used to secure the rails to the backer plates under the wing. Note the rail location in relation to the wing spar. Inset photo shows the 8 pieces that make up the EDF mount. We recommend coating the entire inside of the mount with a thin layer of epoxy as this is a high stress assembly.
This photo shows the EDF unit in place and the wires entering the back of the fuse. Short 16 gauge wire extensions may be needed to reach the ESC. Note we have wrapped a piece of black electrical tape around the EDF unit. This gives the metal strap extra grip.
The photo above shows the aileron, rudder, and elevator servos and pushrods. Note that the aileron and rudder servos are installed the same as the Aqua Cat. The 18 elevator pushrod has been routed through the guide tube. We used a Z-bend on the servo arm and an adjustable EZ Connector on the horn. The elevator servo is glued to the side and bottom of the lower fuselage with a few dabs of hot melt glue. Note: The rest of the build is identical to the Aqua Cat. CG and control throws are the same.
Aqua Cat SE The Aqua Cat SE is identical to the Aqua Cat with a few exceptions: The foam is pre-painted, a plastic canopy is included, and the decals are different. Use extra care when assembling the SE to avoid getting excess glue on the painted surfaces. For the canopy, we sprayed a light coat of black on the inside, then trimmed the frame in silver. To attach the canopy, we glued some scrap foam on the bottom at each end, then glued it to the top of the fuselage hatch. The canopy will bend to conform to the curve in the fuselage top. Use the photo above for decal placement. Note that the wing checkerboard and tail checkerboard are slightly different. The piece with ModelAero.com on it is the left wing piece, and the other wing piece is directly across from it on the decal sheet. Note that these decals simply peel and stick. There is no backer paper that is usually on the decals.
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