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Mountain Models Flashback

 

37

 

 

• 

To bevel or taper the piece, place it on your worktable with the edge you are 

working on lining up with the edge of the table. Using one bar sander to hold 

the piece down, use another bar sander to do the actual sanding.  

• 

While sanding, try to go over the entire edge in a sweeping motion, avoiding 

any part of the assembly that is to remain non-beveled. This will make sure that 

your bevel angle is even across the entire way.  

• 

Make sure that you sand lengthwise with the grain and not across it, as this will 
cause less strain on the wood and less chance of breaking the pieces. 

• 

Using a tack cloth, carefully remove the balsa dust once you are done sanding. 

Assembling the Rudder 

To assemble the rudder, you are going to need the following pieces: 

• 

Rudder Assembly (Figure K

 

Putting the pieces together 

1. 

Position the pieces as shown below and then glue the joints together. 

 

2. 

Once the parts are dry, carefully remove them from the wax paper. 

3. 

Bevel two 45

°

 angles into the leading edge of the rudder to form a “V” shaped point. If 

it’s easier to think about it this way, it should be 45

°

 to the center on both sides, which 

will cause a point to appear. 

Note the three 

individual pieces in this 

image 

Summary of Contents for Flashback

Page 1: ...Flashback Specifications Wingspan 36in 91cm Length 36 in 91cm Wing Area 265in2 1710cm2 Weight without battery 12oz 340g Wing Loading depending on battery 8 5 10 0oz ft2 ...

Page 2: ...udder full house setup designed for the intermediate to advanced pilot who wants a plane with outstanding performance that will fly in a limited space Sincerely Doug Binder doug mountainmodels com Mountain Models 6975 Blackhawk Place Colorado Springs CO 80919 www mountainmodels com Phone 719 592 1387 Fax 719 528 6125 Created by Ross Design Group for exclusive use by Mountain Models ...

Page 3: ...blades Needle nose pliers Wire cutters Sanding block with 200 grit sandpaper 90 triangle or small square to true the bulkheads and fuselage Covering material if not using the supplied Doculam Sealing iron for applying the covering Clear tape for aileron hinges 4 channel radio 4 channel receiver GWS EPS400 C motor with a GWS HD 10x7 propeller 3 micro servos we recommend either the Hitec HS55s or th...

Page 4: ...od Figure C 1 16 laser cut balsa sheet Figure D 1 16 laser cut balsa sheet Figure E 3 32 laser cut balsa sheet Figure F 1 16 laser cut balsa sheet Figure G 1 16 laser cut balsa sheet Figure H 1 16 laser cut balsa sheet Figure I 1 8 laser cut balsa sheet ...

Page 5: ...ck 5 Description of Parts Wood Figure J 1 32 laser cut balsa sheet Figure K 3 32 laser cut balsa Figure L 1 8 laser cut balsa sheet Figure M 1 64 plywood sheet Figure N 1 4 laser cut balsa for cowl Figure O 1 16 plywood sheet ...

Page 6: ...screw General Building Tips Tape your plans to the work table and then cover them with wax paper to protect them Balsa is a lightweight and fragile wood so you do need to be careful with it however you will also need to use a little bit of force to make everything fit properly so don t be too timid Join all of your pieces using thin CA Cyanoacrylate glue unless we tell you otherwise In general onl...

Page 7: ... the kit up with the tail wheel batteries landing gear canopy throws and center of gravity Final Step On a calm day find a field without too many trees or light poles and go fly Experienced builders may notice that this building order goes against the normal building conventions We have found that fewer pieces get mangled this way since you are building the stronger pieces first For example the ta...

Page 8: ...ve two left or two right sides which may work for a profile plane Assembling the Fuselage Sides For the fuselage sides you will need 2 Fuselage Pieces Figure A 1 Fuselage Piece Figure B 1 Fuselage Piece Figure C Assembling the sides 1 Remove the fuselage pieces shown in black from the balsa sheets To remove the pieces gently flex the balsa sheets until the pieces fall out You may find that you nee...

Page 9: ...parated remove the CA glue from your fingers using nail polish remover or acetone making sure you wash your hands thoroughly when done 4 Once the glue is dry carefully remove them from the wax paper Attaching the Fuselage Reinforcement Pieces The fuselage reinforcement pieces or fuselage doublers are used to reinforce the fuselage and are placed on the interior walls of each fuselage side Yet agai...

Page 10: ...er Figure B with the larger oval slot and the wing opening located on the fuselage side You will find that if the doubler is in the wrong spot the larger oval slot in both the doubler and the fuselage side will not line up 2 Make sure everything is lined up including the wing opening the larger oval slot and the outside edge and then glue the fuselage doubler into place Fuselage doublers ...

Page 11: ...te side of the wing opening and the slot 2 Make sure that everything is lined up including the slot and the wing opening and then glue into place 3 Repeat for the other fuselage side using the other doubler shown in Figure D The fuselage doublers used in this section and the one above are used to strengthen the area around where the wing will mount Since the wing goes entirely through the fuselage...

Page 12: ...following pieces Fuselage tail and Fuselage bottom Figure D Attaching the tail 1 Line up the tail piece with the rear edge of the fuselage bottom matching the point and the cutout as shown in the following picture 2 Glue the fuselage tail in place Assembling and Attaching the Bulkheads The bulkhead assembly process consists of reinforcing a bulkhead and assembling the servo tray The bulkhead attac...

Page 13: ...sed later has more support You will need Bulkhead F4 Figure A Bulkhead reinforcement piece Figure C Reinforcing the bulkhead Line up the arch of the reinforcement piece with the top edge of the F4 bulkhead Do NOT line up the tabs along the side the reinforcement piece instead use only the arch section of the pieces for this purpose Bulkhead reinforcement ...

Page 14: ...e fuselage 2 Arrange the two smaller servo tray pieces we are going to call them servo spacers for clarity one on top of the other lining up the small screw holes Glue the two pieces together You may find it easier to line up the two pieces by putting a long pin through each of the screw holes to hold the pieces securely together 3 Arrange the piece you created in Step 2 so that it sits over the t...

Page 15: ... F3 Bulkhead Figure O Landing gear spacer Figure L Attaching the landing gear spacer Line up all of the available edges of the landing gear spacer to the F3 bulkhead and then glue the pieces together Attaching the Bulkheads to the Fuselage Bottom In order to attach all of the bulkheads to the fuselage bottom you are going to need Fuselage Bulkhead F2 Figure O ...

Page 16: ... tabs located on the bottom of the F2 bulkhead into the matching slots of the fuselage bottom as shown in the picture below 2 Position the assembled F3 bulkhead into the slots right behind the F2 bulkhead making sure that the landing gear spacer is placed between them also shown in the next picture 3 Make sure the bulkheads are perpendicular and fully seated on the fuselage bottom and then glue th...

Page 17: ...n the F4 and F5 bulkheads with the spacers pointed downwards and forward toward the nose of the plane Attaching the servo tray 1 Slide the servo tray created in the Assembling the Servo Tray section above into the three slots at the center of the F4 bulkhead The piece will now be on an angle with the opposite side resting against the F5 bulkhead 2 Carefully flex the F5 bulkhead so that you can gen...

Page 18: ...s point of view Imagine your pilot sitting in the cockpit looking out the cockpit window and then determine his left and right This is the point of view that will be used throughout these instructions Attaching the Left Fuselage Side to the Fuselage Bottom Attaching the left fuselage side 1 Line up the left fuselage side with the left sides of the bulkheads pushing everything gently into place as ...

Page 19: ...on the battery mount support and fuselage braces within the interior of the fuselage itself You will need the following pieces 1 Plywood battery mount support brace Figure O 2 Balsa fuselage braces Figure L Positioning the plywood support and fuselage braces 1 Position the plywood support from Figure O into the slot located in front of F4 above the wing cutout Glue into place 2 Position the smalle...

Page 20: ...fuselage This process is a bit difficult because the space is kind of tight and there are a lot of individual bits to line up Be patient and try not to use excessive force Keep in mind though if you push too hard well it adds character and CA nothing that everyone hasn t done at LEAST once 2 Ensure that the fuselage is straight and then glue the right fuselage side to the bottom and both the right...

Page 21: ...ard the tail 2 Position the smaller brace into the slot on the fuselage side between bulkhead F6 and F7 also with the taper facing aft 3 Making sure that everything is aligned and square glue both the left and right fuselage sides from bulkhead F4 to the very end of the tail 4 Making sure that the braces you just positioned are flush with the fuselage sides glue them into place Attaching the F1 Bu...

Page 22: ...ke it easier to move around without cracking or stressing If you do dampen the balsa you will need to position the bulkhead but wait to do the actual gluing until the fuselage has dried This shouldn t take long since you just dampened the wood but the time will vary depending on your definition of dampen 2 Position and connect the bottom of the fuselage with the F1 bulkhead using the tabs and slot...

Page 23: ...rial on the inside of the square opening of the motor mount This will allow the motor mount to slide more smoothly into place 2 From the outside of the fuselage sides slide the longer motor mount support through the fuselage body and into the slots closest to bulkhead F2 and then slide the shorter support into the slots closest to bulkhead F1 3 Make sure that they are centered within the fuselage ...

Page 24: ...4 motor mount pieces Bagged Parts Assembling and Attaching the motor mount 1 Position the motor mount pieces into a 3D rectangle using the tabs and slots on each piece 2 Make sure that everything is square and then glue the joints 3 Once the mount is dry lightly sand its outside surface so that the motor slides on snugly but is not overly tight 4 Slide the motor mount through the square motor moun...

Page 25: ...ear 2 Spray the entire piece with water or ammonia so that it s more flexible and less prone to splitting while you are manipulating the piece into place 3 Carefully bend the sheeting over the tops of the bulkheads and the top stringers lining up the smaller end with the F7 bulkhead and the larger end with the F3 bulkhead 4 Secure the piece into position using five rubber bands one at each bulkhea...

Page 26: ...fits over the cowl area and as such does not need to be wetted Cowl sheeting Figure J Attaching the cowl sheeting 1 Form the sheeting over the tops of the F1 and F2 bulkheads lining up the smaller end with the F1 bulkhead and the larger end with the F2 bulkhead 2 Secure the piece into position using two rubber bands one at each bulkhead 3 Glue the underside of the sheeting where it meets each bulk...

Page 27: ...e staggered 3 Center the cowl pieces onto the F1 bulkhead and then glue them into place 4 Sand the front of the cowl to give it a nice rounded look Step 3 Assembling the Wings Once you ve finished building the fuselage you can begin assembling the wings You have now completed one large step for your plane and one small step well you know the rest Assembling the Wing Spars and the Trailing Edge For...

Page 28: ... ends while the other two pieces will join to form a spar with squared off ends 2 Trim off any excess balsa pieces from where the spars were removed from the balsa sheets We are going to call these nubs from here on out 3 Position the pieces by aligning the notch and groove to form one long vertical spar Make sure all of the slots on the vertical spars are facing the same direction This is EXTREME...

Page 29: ...create a single full spar are grouped together for simplicity Two of the pieces will join to form the top spar piece marked TOP on the balsa while the other two pieces will join to form the bottom spar 2 Position the pieces by aligning the notch and groove forming one long spar and then glue the pieces together 3 Repeat for the two remaining spars Assembling the Trailing Edge You will need Trailin...

Page 30: ... and Attaching the Edges Next you are going to position the wing ribs and attach the vertical spars the top and bottom spar caps and both the trailing and the leading edges DO NOT glue any of the pieces within this section until we tell you to in the Attaching the Leading Edge section You still need to finish attaching the wing spars and trailing edge Once everything is in place THEN you ll glue i...

Page 31: ... into the remaining vertical spar slots gradually getting smaller toward each of the wing tips See the picture for a more detailed view 4 Slide the aft vertical spar the vertical spar with the squared ends into the remaining slots on the wing ribs Positioning the Top and Bottom Spar Caps You are now ready to position the top and bottom spar caps onto the wings so you re going to need the top and b...

Page 32: ... air That way as you push the bottom spar cap into position you aren t flexing the wing and causing potential breakage or stress Positioning the Trailing Edge Now you are ready to position the trailing edge onto the wings so you are going to need the trailing edge you created previously for this step Positioning the trailing edge 1 Position the trailing edge along the wing ribs lining up the slots...

Page 33: ...eed to make sure that the wing ribs stay straight since it s really easy to tweak them one way or another while you re gluing I ve found that the best way to make sure things stay straight is to hold the wing so that the trailing edge is on the table and the leading edge is facing the ceiling Position the leading edge into the outermost slot for the wingtip rib Line up the rest of the leading edge...

Page 34: ...flush against the wingtip ribs 2 Trim off any nubs from the flat face of each of the wingtip pieces 3 Position the wingtips using the slots and grooves on the trailing edge and the forward vertical spar as shown in the next picture and then glue them into place Assembling the Aileron Servo Block You are going to assemble the aileron servo block which will be used to house the aileron servo in a la...

Page 35: ...lush with the bottom edge of the spar 2 Glue the aileron servo block into place Step 4 Assembling the Stabilizers Rudder and Elevator The first things that you are going to assemble are the stabilizers rudder and elevator When assembled these are also known as the tail feathers Assembling the Horizontal and Vertical Stabilizers To assemble the horizontal and vertical stabilizers you will need Hori...

Page 36: ...big pieces until you are attaching the tail feathers Beveling the Horizontal Stabilizer Even though you don t have to build anything for this section you do have to bevel the piece so that it works correctly with the rudder Beveling the horizontal stabilizer Bevel two 45 angles into the trailing edge of the horizontal stabilizer to form a V shaped point If it s easier to think about it this way it...

Page 37: ... not across it as this will cause less strain on the wood and less chance of breaking the pieces Using a tack cloth carefully remove the balsa dust once you are done sanding Assembling the Rudder To assemble the rudder you are going to need the following pieces Rudder Assembly Figure K Putting the pieces together 1 Position the pieces as shown below and then glue the joints together 2 Once the par...

Page 38: ...will need 1 32 x 18 tail wheel wire Wire of CA hinge material Bagged Parts Shaping the tail wheel wire Bend the 1 32 x 18 wire following these steps and referring to the plans Needle nose pliers work pretty well to shape the wire 1 Put a 90 bend into the wire 3 8 in from the end 2 From that bend go in 1 2 and create a slight 45 bend Bevel a 45 angle into both sides of this entire edge so that it c...

Page 39: ... Rudder 1 Make a small hole in the thickness of the rudder s beveled edge using the plans as a guide Using a T Pin to ream the hole makes it just the right size for the wire 2 Position the tail wheel wire with the 90 bend into the hole you just created 3 Using a strip of the CA hinge material wrap it around the rudder and the tail wheel wire and then glue into place Assembling the Elevator To asse...

Page 40: ... the halves is determined by positioning the elevators into their positions in relation to the horizontal stabilizer There should be a 1 16 gap between the sides of the horizontal stabilizer and the forward area of each elevator half Trim the dowel to fit if necessary 3 Glue the dowel into place with thick CA Step 5 Assembling the Ailerons Okay so this stage where you are going to assemble the ail...

Page 41: ... edge The bevel should be such that the aileron touches the top of the wing not the bottom The side you sand will determine which will be the left and right aileron Make sure you create one left aileron and one right aileron this is EXTREMELY important We recommend determining left and right so that the control horns are facing forward towards the nose of the plane Step 6 Assembling the Landing Ge...

Page 42: ...d then glue them in place Use the landing gear wire to measure the gap between the balsa and plywood parts to make sure that it fits without being too snug or causing gaps 3 Locate the center of the landing gear wire and bend it into a 70 angle and then measure from each end of the landing gear wire and bend a 125 angle into each See the following picture for reference 4 Insert the landing gear wi...

Page 43: ...canopy in place You will need Canopy frame pieces Figure L Plastic canopy To put together the canopy 1 Trim the nubs from the canopy mount pieces and then position the pieces as shown in the following picture 2 Make sure that all of the pieces are perpendicular and then glue the joints 3 Cut out the front and rear most sections of the plastic canopy 4 Position the canopy mount inside the plastic c...

Page 44: ... will crack the plastic Step 8 Sanding and Covering The next step is to sand the pieces that need to be sanded and cover everything We aren t going to go into how to cover the pieces themselves you re going to have to refer to your covering s instructions for this information Additionally we aren t going to cover our kit for instructional purposes since the covering hides too much Sanding the Flas...

Page 45: ...hat they are smooth but not rounded While sanding try to go over the entire edge in a sweeping motion avoiding any part of the assembly that is to remain non beveled This will make sure that your bevel angle is even across the entire way Make sure that you sand lengthwise with the grain and not across it as this will cause less strain on the wood and less chance of breaking the pieces Using a tack...

Page 46: ... of the balsa Cutting the Slits for the CA Hinges You need to cut slits into the tail feathers to allow for the CA hinges to be attached Cutting the slits Cut a 1 wide and 1 4 deep slits into the stabilizers elevator and rudder as shown in the plans and described below The slits should be exactly centered into the depth of the wood Tail Feather Piece Description of Slit Area Elevator One slit into...

Page 47: ...ing this since scored wood is weak wood Attaching the Elevator and the Horizontal Stabilizer 1 Insert the elevator through the larger slot at the back of the fuselage making sure that the control horn is on the right side when looking at the plane from the rear You have to attach the elevator before the horizontal stabilizer or you will NEVER be able to fit it into position There is a bit of a tri...

Page 48: ...ove and then glue it into place in the fuselage being extremely careful to avoid the elevator Installing the Vertical Stabilizer and Rudder Next you are going to install the vertical stabilizer and rudder Removing the Covering from the Sheeting You need to remove some of the covering on the sheeting so that it can attach securely to the vertical stabilizer Removing the covering 1 Position the vert...

Page 49: ...rear of the fuselage and that it s perpendicular to the elevator Attaching the CA Hinges You are going to need CA Hinge Material Bagged Parts Attaching the hinges 1 Cut the hinge material into two 5 16 strips 2 Position the two hinges into their slots on the vertical stabilizer and then maneuver the rudder so that one by one the hinges can be lined up and slid into the slots in the rudder 3 Glue t...

Page 50: ...hrough the fuselage using the wing slots making sure that it s centered To make sure that the wings are centered measure from the outside rear corner of the wing tip to the bottom of the fuselage on both sides The values should be equal 3 Flow thin CA around the wing and fuselage joints Do not use thick CA on this joint You want it to be strong but you also want some give if a plane ground joining...

Page 51: ...hin CA into where the servo screws go into the servo tray Make sure that you don t clog the screw pilot holes and make sure you allow the glue to dry completely 2 Install the micro pushrod connectors into the outside hole of the two arm servo horn 3 Position the servos into the servo tray so that they are straight and then screw them into place using the screws that came with your servos Step 12 A...

Page 52: ...ra thread for pull pull system Bagged Parts 4 Cotter pins for the pull pull cables Bagged Parts Routing the cables The Spectra thread has a coating on it to make it waterproof You will need to remove this coating where you tie off the thread to set the knot with CA To do this run the dull edge of a Xacto blade along the length of each thread where you will be tying the knot 1 Flow some thin CA int...

Page 53: ...g the servo 1 Flow some thin CA where the servo will be mounted Make sure you allow the glue to dry completely 2 Using the hole provided in the bottom of the fuselage center the servo using the midpoints you marked earlier and then screw it down 3 Using a 4 length of the wire z bend one end and insert it into the outermost hole of the plywood control horn Correct Control Horn Hole Selection Hole c...

Page 54: ...pinner facing forward Make sure that it s FULLY seated 2 Using the round hole provided in the bottom of the fuselage use a 1 16 drill bit to go through the gear box and the plywood motor mount 3 Screw in the motor retaining screw Step 15 Attaching the Receiver and Speed Controller We are not going to cover the receiver and speed controller ESC specific information please refer to your manufacturer...

Page 55: ...ng the Kit Well you re almost there the end is in sight just a few more steps and you can go flying assuming the weather is cooperating Attaching the Tail Wheel This is one of those highly overlooked but extremely important pieces if you want your backend to remain in one piece For the Flashback we are using a tail wheel You will need 1 piece of the 1 32 x 18 thin music wire Wire 1 tail wheel Bagg...

Page 56: ...tery strap 1 2 x 3 8 screw Attaching the battery 1 Cut the rough side of the Velcro strip down to 4 1 2 in length and then attach it to the top of the battery mount 2 Slide the 1 16 plywood battery mount with the tabs facing toward the nose of the plane into the slot of the F2 bulkhead 3 Secure the back of the battery mount to the 1 16 plywood fuselage battery mount brace using a 2 x 3 8 screw 4 A...

Page 57: ...nd are ready to finish up You will need Canopy assembly assembled earlier 1 1 4 x 1 4 x 3 4 balsa stick with metal tack 1 Neodymium magnet rare earth magnet Attaching the canopy 1 Hinge the entire right side of the canopy assembly to the fuselage with a 3 4 strip of packing tape 2 Remove the tack from the balsa stick and then position the stick on the left side of the fuselage so that it s just in...

Page 58: ...eed On the other hand too far back and the plane will be hard to control requiring constant input to keep the plane flying straight and level For the Flashback refer the position shown on the plans Use this as a starting point you can slowly move it back as you get more comfortable with the plane Flying For your first flight be patient and wait for a calm day Choose a large field where you have a ...

Page 59: ...Mountain Models Flashback 59 A Few Pattern Flying Maneuvers Half Cuban Eight Knife Edge ...

Page 60: ...Mountain Models Flashback 60 Immelmann Turn Modified Immelmann Turn ...

Page 61: ...Mountain Models Flashback 61 Humpty Bump Hammerhead Pattern flying images are brought to you in part from the Dundee Model Aircraft Club Web site http www dmac org uk All images have been modified ...

Page 62: ...ice visits 60 00 720 00 TOTALS 1 240 67 14 888 00 Full Scale Aerobatic Ownership 1 pilot Aerobatic Trainer 1 1 scale Annual Fixed Expenses Item Cost year Tiedown Hangar 3 000 00 Insurance 1 800 00 Annual Fixed Expenses Item Cost year State Fees 150 00 Annual Miscellaneous 500 00 Maintenance 1 000 00 Loan Payments based on a 45 000 00 plane 3 568 07 Cost of Capital non cash 1 575 00 TOTALS 11 593 0...

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