Model Aero Polaris XL

Transcription

1 Model Aero Polaris XL We are very excited to introduce the newest model in the Polaris line, the Polaris XL. The XL is a 133% version of the standard size Polaris, and the larger size only enhances the flight characteristics that made the original such a popular airplane. The wing loading is even lighter and the gentle flight performance will amaze you, yet the XL is capable of some impressive aerobatics and a surprising turn of speed! We re extremely pleased with how the kit turned out, and you ll find the build to be very straight forward and enjoyable. Scott DeTray Model Aero Specifications: Designed by Steve Shumate. Based on the North Star design by Laddie Mikulasko Special thanks to Nigel Chippindale for doing the test build and flight testing. Span: 38.5" Length: 53 Wing area: 606 sq in Weight RTF: 28 to 34 oz Wing loading: 7 oz/sq ft Motor: Spin Max or Prop: motor- Master Airscrew 8 x 6 3 blade or APC 8 x 6, motor-apc 6 x 4 Battery: 2100 to 3000 mah 11.1V lipo Speed control: 40 amp Receiver: 4 channel Flight controls: Elevator, ailerons, rudder, throttle

2 Power for the Polaris XL By Nigel Chippindale The XL has quite specific requirements when it comes to choosing a motor. The motor must be able to deliver at least 220 watts of power to a propeller of 8 or less diameter using a three-cell LiPo battery. This means that it needs to have a KV rating between about 1400 and 2200 and an ability to withstand a current of 22 to 30A. For good performance, the motor must be well matched to just the right propeller. Note that the XL gets its excellent flight characteristics in part from its light weight and low wing loading. It will not fly better with a bigger, heavier motor than recommended. Moreover, the structure is designed for motors of up to about 80g. Two motor/propeller packages are recommended for the Polaris XL: Package #1: Polaris Motor ( with 6x4 prop) This package uses the standard motor recommended for the 100% Polaris, the Suppo/Spinmax , which weighs 47g. This motor has a KV of 2200, spins a 6x4E APC propeller at 19,000 RPM, and can take up to 28A for 60 seconds. The motor will draw about 20-22A at takeoff and in full throttle flight and cruise at 12 to 15A. Recommended ESC is 40A and the battery should be about 3s 2200 mah 20C. The Polaris XL with this 220 watt motor flies beautifully at moderate speed and can maintain a steep climb. It gets off the water or grass easily. Typical all-up weight should be oz. Flight duration should be about 6-8 minutes, depending on how much you use high power settings. Package #2 (recommended): Larger Motor ( with 8x6 3-blade prop) This package provides higher performance using a Suppo/Spinmax motor weighing 78g. It has a KV rating of 1410, which means that it turns more slowly than the on a three cell battery. The best propeller we have found is a Master Airscrew 8x6 three-blade; an APC 8x6E two-blade prop also works well, but doesn t fully exploit the power of the motor. The motor will draw up to about 30A for short periods and 26-28A in sustained high power flying. Throttled back, it will cruise at about 14-16A. Recommended ESC is 40A or more. While the motor will work well with a 3s 2200 mah battery of 20C rating, given the heavier current draw a 25-30C battery will give a little more power, generate less heat and may have better life span. With this motor of over 300 watts, the Polaris XL accelerates rapidly on the water or ground and can go directly into a sustained vertical climb. It s significantly faster than with the smaller motor. Typical all-up weight is oz. Flight time should be in the 5-7 minute range, unless you fly at full throttle most of the time. Note that with this motor, the Polaris XL can easily carry a larger battery, such as 3s 3000 mah.

3 Additional Items Required: Glue (Foam safe CA/accelerator, epoxy, 3M77 spray, Foam Tac, or the glue of your choice) Hinge tape 3 pieces of 14 to 16 gauge wire approx. 28 long for motor wire extensions 1 servo wire extension for the elevator servo (12 to 16 ) Power system: motor, ESC, battery, heat sink (optional but recommended) Motor/ESC connectors as required 3 servos (minimum torque 17 oz./in) Construction Before starting construction, read through the entire build guide to get familiar with the parts and construction process. If you are confused by a step, take some time to study the pictures and don t rush it. In this photo, we ve assembled the 3 main wing panels and glued all the carbon spars into their respective slots. At top left is the horizontal stab with the small extension piece attached as well as the carbon spar. We recommend epoxy or Foam Tac for the carbon. If using epoxy, scuff the carbon with some fine sand paper before gluing it in. We have found that putting a strip of Scotch Transparent tape on each side of the carbon pieces really helps stabilize the joint. Note: Use some wax paper under the foam to keep the parts from sticking to your work table.

4 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. Glue on the short fuselage side extension pieces (shown already attached) to the aft end of the fuselage sides. These pieces are found right next to the fuselage side pieces on the laser cut sheet. 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 Tac works well here. After the strips are attached, trim them off flush with the front of the fuselage.

5 F1 Shown above are the 4 fuselage formers in the order they will be installed. We have numbered them (black numbers) in the order we glue them in. This isn t mandatory, but we find it the best sequence. Of course you need to take special care to keep the fuselage sides square when gluing in the formers. 6 3/8 F2 F3 F4 F1 F2 F3 F4 12 ¾ Photo above shows the spacing of formers F2 and F3 relative to the front of the plane. Photo at left shows detail of the rear fuselage former.

6 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. 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.

7 The vertical stab parts shown above consist of two pieces of foam laminated together. We prefer 3M77 spray adhesive for this step. The rudder, at right, will be installed later. Photo above shows the laminated vertical stab 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.

8 Study this picture carefully. It shows the two outer vertical stab pieces glued to the inner laminated vertical stab core pieces. Once the glue is dry, sand the leading and trailing edges to round them off. Photo at left shows the two nacelle bottom pieces glued together. Next, glue strips on one edge of the nacelle sides as shown.

9 Taper the angled ends of the nacelle sides as shown. We simply place the pieces on the edge of our work table and use a sanding block for this. The exact angle is not critical. Using a heat gun or hair dryer, very carefully heat the nacelle sides and bend a curve to match the curve of the nacelle bottom.

10 Photo above shows the nacelle bottom and sides attached to the vertical stab. The foam firewall (inset photo) is attached at the front. Photo at left shows the lower aft fuselage with the servos installed through the servo doubler and wing.

11 There is a lot to see in this photo so study it carefully. Note that the wood vertical tail base support and motor mount have been installed (painted black). Then slide the entire vertical stab/nacelle assembly into place. Next, install the elevator servo using the small piece of foam in the inset photo. Note that we cut a small relief for the servo arm. The motor has been installed and the extension wires run down through the wiring channel. For the extension wires, you will need three pieces of 14 to 16 gauge wire approx. 28 long. The elevator servo pushrod is simply pushed through the foam at the correct angle to line up with the servo arm and elevator. The rudder has been installed using the included CA hinges.

12 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. This photo shows the aileron and rudder pushrods 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. 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 takes steps to be sure it is sealed.

13 Photo above (top of wing) shows the motor extension wires coming up through the wing and attached 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. Note the piece of shrink tube next to the RX. This is just to keep the wiring nice and neat and is not required. Photo at left 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. Note that the ESC/heatsink has been mounted to the top of the hatch.

14 Photo above shows the entire fuselage top in place. The dimensions shown are for reference only. This particular plane has a motor and is setup for a 2200 battery. The location of the hatch and the lengths of the pieces may vary depending on gear used. Just plan ahead before cutting the top fuselage piece. Note: The style and location of the access hatches is really up to the builder. You may wish to simply glue the entire top piece on and then cut individual hatches for RX and battery as needed. At left are the tip floats (6 pieces per side) and nose block (12 pieces). Simply sand these pieces smooth and contour the nose to a pleasing shape. The tips floats mount flush with the wingtip.

15 We re almost done!!! Complete the build by attaching the horizontal stab and vertical fin. make sure the elevator servo is setup perfectly before gluing the stab on. A small access hatch can be added later if access is ever needed. Note: If using the optional decal set, see below.

16 Decal Application Note: Decal application procedure is the same for all kits. 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.

17 Setup and Flying Note: The Polaris XL 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: ¾ each way (40% exponential) Ailerons: ¾ each way (40% exponential) Rudder: 1 ½ (25% exponential) Low rates: 70% of the above settings. The recommended CG location is on the fuselage step or up to ¼ ahead of it. Taxiing on the water is very straightforward. The model tracks well and steers easily with rudder inputs, in large part because the rudder is located in the prop slipstream. 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! Landings are easy. You can either fly the model onto the water for a gentle skipping landing, or you can flare hard and watch the airplane plop into the water with remarkably little forward speed and a landing run of only a few feet. Because of the delta wing design and the wing leading edge strakes, this model can pitch up very nose high during landings. However, remember that when flying at high angles of attack the drag is very high, so you'll need to carry a little throttle to keep the model from descending too rapidly

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