We are excited to introduce the Model Aero Spirit. Inspired by the magnificent Northrop Grumman B-2 Spirit Stealth Bomber, the Spirit is a great flyer, on land or water. It tracks like an arrow and is capable of an impressive turn of speed. The Spirit signals a new direction for Model Aero as it is made entirely of Model Plane Foam (MPF). This change was necessary because Depron foam has been discontinued in the US. MPF is very similar to Depron with a few differences. It is somewhat softer and more flexible than Depron, necessitating a few changes in construction. It s much less brittle than Depron so crash worthiness is better. As far as general construction goes you will find few differences. Probably the biggest change in construction is that we have introduced a KF airfoil on the wing. This is primarily for strength although it does add some lift as well. We ve flown it both with and without the KF and it s nearly impossible to tell the difference. But it does add a lot of strength. I hope you enjoy the Spirit as much as I have. Scott DeTray Model Aero
1 Specifications: Wingspan 40.5" Length 30.0" AUW 17-22 oz. Wing area-300 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 (12 gram) 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 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 or Aqua Cat kit. In these cases the build is identical to the Spirit. 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.
Parts Identification 2
3 Construction Note that with MPF one side of the foam is slightly smoother than the other. We prefer to orient the pieces so that the smooth side is most prominent, such as the top of the wing, outside of the fuselage etc. In this photo, we ve assembled the main wing panels and front wing extensions and glued all the carbon spars into their respective slots. We typically use epoxy for the spars. 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.
4 Glue in the spar for the horizontal stab and hinge the elevator. Next, attach the wing doublers to the bottom of the wings, making sure the pieces are flush with the leading edge and wing tip. Note that the slot for the wing floats is towards the outside of the wing. Sand the leading edge of the wing to a pleasing rounded shape. We have used a metal straight edge and a very sharp utility knife to bevel the leading edge top and bottom, then finish it with sandpaper. If using this method, be extremely careful!!!
5 Leave 1/8 of tape to ease removal. Flush It is much easier to apply the wing and elevator decals before the rest of the plane is assembled. It is critical to remove all the sanding dust from the foam before applying the decals. We use packing tape to pull off the dust. Also, application of the decals should be done in a warm room. The tape will release easier if the ambient temperature is above 70 degrees. Trim and apply the front wing decal first, making sure it is flush on the edges shown. Leaving a little tape on the left side will make give you something to grab onto when removing the application tape. Press the decal firmly and repeatedly all the way around. If the decal wants to lift as you remove the tape there are a couple things you can do. First, press the decal back down if it starts to lift off. Second, use some Windex on a paper towel to moisten the tape. Third, waiting 30 to 40 minutes after applying the decal and before removing the tape will give the decal a chance to set. Patience is the key here.
6 Trim and apply the second part of the decal the same way, making sure it s flush with the first decal piece. We use sharp tweezers to grab the backing tape. Use the same technique to apply the left and right elevator decals. In the picture above we ve attached the fuselage doublers to the front lower part of each fuselage side. Make sure you have a right and a left side.
The battery tray is now glued to the fuselage sides, resting on the fuselage doublers. Make sure to keep the fuselage sides and battery tray square. 7
8 Step Above photo shows F2 glued into place flush with the fuselage step. F2 should be perpendicular to the wing slot. Former F1 can now be glued to the front of the fuselage.
9 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. We prefer a bead of Foam Tac for this step as it provides a good seal. Once the glue is dry slide the fuselage over the wing and insert all the alignment tabs. Once you are satisfied everything is lined up glue the wing and fuse together. The vertical stab inner parts (incorrectly called Nacelle Center on the parts identification) are shown above. The rudder, at right, will be installed later.
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. 10 Photo above shows vertical stab inner 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 wire. 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. The tape only needed if using spray adhesive for this step. Photo above shows the two outer vertical stab pieces glued to the inner core pieces.
11 Next, sand the leading and trailing edges of the vertical stab to a pleasing rounded shape. Next, sand or cut a bevel on one end of the nacelle side pieces as shown.
12 The nacelle bottom is shown attached to the vertical stab. Carefully bend a curve in the nacelle sides to match the nacelle bottom. MPF is easily cold formed using a round form such as a can of spray paint. You can practice this technique on some scrap foam. Once the nacelle sides are shaped and attached, glue the foam nacelle front on and then the wood motor mount with Foam Tac or 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 using the included CA hinges.
13 Shown above are three 18 to 20 16 gauge 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 motor has been installed, and the motor wire extensions and elevator servo wire are shown exiting the vertical stab (Polaris shown, Spirit assembly is identical). Note that you may wish to install the nacelle and vertical stab assembly before running the wires and attaching the motor. We have done it both ways.
14 Wood tail base support 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!
15 Above photo shows the routing of the motor extension wires and elevator servo wire. Also notice the rudder pushrod and plastic guide tube. There will be some flex in the rudder pushrod which is designed to protect the servo when the rudder is contacting the ground. This photo shows the rudder pushrod attached. At this time attach the aft fuselage bottom piece. For water operations it is critical that this piece is sealed well. If you notice any gaps seal them with glue, latex caulk, or scrap foam. Note the adjustable connectors on the rudder and elevator control horn.
16 The aileron and rudder servos are in place. Note the wood aileron servo arm is screwed to the plastic servo arm with servo mounting screws. If using Model Aero servos the holes will line up. If using other servos you may need to drill holes to mount the wood arm. The wire pushrods are shown exiting the fuselage side through the small pre cut slits and on out to the ailerons. The adjustable connectors are attached to the wood arm. The rudder pushrod guide tube is visible sticking up through the wing.
Note in this picture the 4 ¾ carbon rods and 3/32 shrink tube have been applied to the push rods for added stiffness. 17
18 5 9 3 In the above photo we have final sanded and fit the fuselage top piece and rounded the top edges, and applied the decal (1 ¼ from the front of fuselage). There are a few ways to configure the hatches for battery and RX access. Our favorite method is to cut the top piece in 3 pieces with the center section removable. Note the dimensions in the photo. Also note the location of the optional heat sink. We use scrap foam to make small tabs to hold the center hatch in place. The battery will sit just ahead of or partially under the ESC. The battery must be positioned to achieve the proper CG. Extra wire can be tucked into the opening at the rear of the battery tray. Once the aileron push rods are installed and adjusted, glue or tape the small hatch cover into place.
19 Laminate the wing float pieces together with the tabbed piece in the center. We chose to taper them as shown. These attach by inserting into the slots in the lower wing. The nose pieces are laminated together and then carved/sanded to match the fuselage contours.
20 Congratulations on completing your model! Note that we have painted the nose piece. This is not necessary and can be left white. Setup and Flying Note: The Spirit 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. FAA registration required. 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. Note: The recommended CG location is ½ to ¾ ahead of the fuselage step. www.modelaero.com 419-966-2230
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