R/C Scale Model Instructions

Transcription

1 Fokker D. V 43 Fokker D.V 43 R/C Scale Model Instructions CONTACT INFORMATION Designed by M.K. Bengtson Prototype by Bert Ayers Manufactured and Distributed by: Bengtson Company e mail: sales@aerodromerc.com

2 Fokker D. V 43 Page 1 Fokker D.V 43 Thank you for purchasing the Fokker D. V model kit for electric flight. Finished Model the cockpit area. 2 pieces of 1/16 sheet balsa for the bottom wing first rib bay cover. For the wings 6 1/4 x1/8 x24 and 2 1/8 x1/8 x24 Bass or Spruce spars are needed. 4 1/4 x1/4 x24 Balsa leading edge pieces are needed. 4 lengths of 1/8 square Balsa longerons and 5 1/8 x1/16 x101/2 Balsa stringers are needed. 3/32 music wire is needed for the cabane struts and wheel axle 1/16 music wire is needed for the landing gear legs and the rudder tail post. 1/8 brass tubes are needed in the top wing and fuselage and elevator hinge. 5/32 aluminium tube is needed for the elevator hinge, and 3/32 aluminium tube is needed for the rudder hinge. This builder also used a small piece of 5/32 aluminium tube (opened up) at the end of the tail skid. Use the plastic bag that the kit comes in to cover the plans in each of the building steps. Slit the bag down the side and sealed end to open it up into one large sheet. THE MODEL A semi scale adaptation of the FOKKER D. V, this model is designed to be easy to build and exciting to fly. Self aligning wings for fast, accurate assembly. POWER SET UP The model can be set up to be powered by the Long Can Speed 400 (sometimes called a 480) with the MP Jet 3.46:1 BB Gearbox and 10 inch APC Prop. Battery power pack can be 8 600maH Nicads or equivalent Nimh or Li Po. R/C GEAR A four function mini receiver and four micro servos are all that are required. Aileron servos can be no thicker than 11mm to fit into the aileron servo bay. MODEL SPECIFICATIONS More than 220 laser cut parts Scale: 1/8th Channels: R/E/A/T Wing Span: 43 inches Wing Area: 422 sq in Weight: ~ 25 oz Power System: Long Can Speed 400 Prop: 10x7 Wheels: Balsa & plywood, Neoprene foam tires Cowl: Built up balsa and plywood Spinner: Foam and Fiberglas Prototype: Bert Ayers BEFORE STARTING TO BUILD Almost all the wood required for this model is furnished in the kit. Sheet balsa or 1/32 plywood sheet is needed for Cutting Minute Bridges in Laser Cuts Laser cut parts can best be taken out of the balsa sheets by using a #11 X acto blade to cut the minute bridges in the laser cuts. Pushing them out without cutting the bridges may break the part. CA glue was used for all balsa parts and epoxy for the lite plywood parts. Lite plywood parts were also soaked with CA glue for added strength. White glue was used for the trailing edges and the paper wheel cones. Tubing is used for the elevator and rudder hinges. DO NOT USE CA GLUE anywhere near this tubing. CA always seems to head straight for these tubes and they will no longer be hinges. This builder used epoxy for these hinge points. LET S BUILD AN AIRPLANE!

3 Fokker D. V 43 Page 2 TAIL SURFACES The tail surfaces are a good place to start to get acquainted with building with laser cut parts. Find all the S parts (1 thru 12) in the 1/8 balsa laser sheets, cut the small bridges where the laser didn t cut and finish cutting the part. The part should pick out of the sheet with no effort. All the S parts make up the rudder. Cover the plans with the shipping bag and pin down the S parts. CA glue all joints and allow to set for 5 minutes. Cut three pieces of 3/32 aluminium tube as per plan. The top and bottom pieces will be epoxied to S1. The middle tube will be used at later assembly. This builder used some heavy card stock to center the 3/32 tube on the 1/8 balsa. Time to insert the brass and aluminium hinge tubes. KEEP THE CA GLUE FAR AWAY. Cut the brass and aluminium tube to size as per plans. Slide the aluminium tube over the brass. The aluminium tube is 1/32 thicker than everything else. If you are really picky you can raise both elevators 1/64 to center the hinge tube. This builder allowed both tubes to be epoxied in place 1/32 thicker. Then turned the elevator over so that the slight bulge would be on the bottom and not be seen. Now that you are an expert at building with laser cut parts, we can proceed with more complicated structures. WINGS The wing parts require a little prep work before assembly can begin. Starting with the bottom wings find all L laser cut parts and remove them from the balsa sheets. Find the UTE3/BTE3 parts in the 1/32 plywood sheet. Lay them out over the plans and familiarize yourself the structure and to account for all the parts. Cut the 1/4 x1/8 and 1/8 square spars to length on the plans. Find the 2 L3 1/8 balsa ribs. These are the ribs that the wing struts will fit into on final assembly. Strut side supports need to be added to these ribs. Cut scrap 1/8 balsa 1 long by 1/4 deep and glue to either side of L3 ribs centered on the strut hole on the topside of the rib. Sand these pieces to the contour of the rib. Pin Down Tail Surfaces Pieces Unpin and remove from the plans. Sand and round all surfaces or leave the sanding until everything is built. Find all the A parts (1 thru 12) and repeat the process to build the one piece all flying elevator. Pin down all the A parts (actually pinning down all the parts isn t necessary you will find the fit is so good that some pinning is not necessary). CA glue all the joints. Pin Down Pieces Wing Cover the plans with the shipping bag and start the assembly. This builder started by pinning down BTE3 (note that one end has a small angle cut on the scallop this goes on the wing tip joint), and L4 wing tip. Next position the wing spars no need to pin in place, as the wing ribs will give correct spacing. Put the wing ribs in position, pin down where necessary to keep bottom of ribs flat on the building board. The leading edge cannot be put on at this time, as part of it will go below the flat bottom you will see why later. Glue all the joints. Final step is to glue down UTE3. This builder used carpenters glue on the ribs and the scallop area, then put pins at an angle in the center of the scallop to ensure that the trailing edge is

4 Fokker D. V 43 Page 3 perfectly flat on the board. When all glue is dry, remove the wing from the board and glue on the 1/4 square leading edge. This builder pinned the wing down to the building board with the leading edge hanging off the board about a Wing 1/2 to ensure that when the leading edge was glued on all the ribs were still flat to the board. Now the 1/16 balsa sheet can be glue between ribs L1and L2a (on top, of course). Repeat this process with the other wing. If you have a long building board, build both wings at the same time as this builder did. Sand and round off leading edge (see plan for shape) and wing tips. Time to assemble. Cover the plans with the shipping bag. Do each of the following steps on both wing sections at the same time. Pin down lite plywood piece R12. Pin down wing tip R8 and put in the wing spars, pin them against R12 and R8 and let them float in the center. Pin down BTE1 (note the angle on the scallop goes inboard). Pin the 1/8 balsa rib R5 into position. Glue 1/8 ribs R2 in position at the same time glue the spars to R12. Glue the 1/8 square x 5/8 pieces to R12 (the plan is now covered by R12 these pieces go inside R2 and butt to the spars). This builder put in the 1/8 brass tubes in at this time (2 in front spar space and 1 at rear spar space). Using epoxy and also gluing R3 in with epoxy to avoid getting CA glue inside the tubes. R1 can be glued in at this time. Position all the other ribs and CA glue in place, making sure all ribs are flat to the building board. Hold R10 in place and glue along with R11. Glue UTE1 in place in the same manner as you did on the lower wings. Leave the leading edge till later. Wing TOP WING The top wing should be built in one piece. If your building board is not long enough you can build one wing at a time and join them to the center section. The photos and instructions are for a one piece build. First item is to prepare the 1/8 balsa ribs R7 by gluing on the strut support pieces as you did with L3. This time the pieces go on the bottom of the rib and against the wing spars, see the plans. Once again lay out all the laser cut parts to be sure they are all there and familiarize yourself with the placement. Leave the aileron parts aside till later. Cut the 4 1/8 x1/4 spars to length. Find the 1/8 balsa laser cut TE pieces and glue them onto the rear spar top at the wing tip position. These will become the attach point for the ailerons. Cut 6 1/8 brass tubes to 1/4 length (cabane mounting points). Cut 4 1/8 square x 5/8 balsa pieces from scrap. These are support pieces for the brass tubes. Leave the wing pinned down. Make a pencil mark on the plans where aileron tip parts R9b & c are positioned, as the plan will be covered by part R9. Gather up all the aileron parts. Pin down R9 and BTE2 (note that the angle on the scallop goes outboard this time). Put in 1/8 rib R5a and 1/16 rib R6a against R9. Slide in laser cut LE piece, this will form the spacing for the aileron. Glue these parts together. Avoid gluing LE to the rear spar.

5 Fokker D. V 43 Page 4 Glue in the 3 other R6a ribs and the M piece (aileron horn mount). Also glue down the 9abc pieces. Glue down UTE2 in same manner as before. Mount the servo to the plywood plate in your favorite manner. This builder choose to glue 2 small wood blocks and screw the servo to the plate. Unpin everything. Remove the ailerons and wing from the plans. Cut the 1/4 square leading edges to length and glue to the ribs as you did with the lower wing. Sand the wing and leading edge as per plans. AILERON BAY Find the 1/32 plywood plate that the aileron servos mount on. Working on the bottom of the wing, position the plates between ribs R5 and R6 with the servo arm slot to the outboard R6. This plate can be mounted on the bottom of the wing or as this builder did, set into the rib bay. Either way, use scrap wood to surround the bay to have something to mount the plate to. This builder choose to hold the plate in position with 4 40x1/4 screws. Later when the aileron is mounted to the wing, bend a small push rod to fit between the servo arm and aileron horn, using Z bend at both ends. Bend a V shape into the push rod to allow adjustment of the length by opening the V or closing the V.

6 Fokker D. V 43 Page 5 BUILDING THE FUSELAGE fuselage box. Be careful to not block the lower wing mounting slots. Find 1/8 lite plywood parts F1a, CM1, CM2, CM3, study the plans to see how they are assembled around the brass tubes. Cut 3 1/8 brass tubes to 35/8 long, sand the outside to rough them up so the epoxy will hold fast. Epoxy this series of parts to the top front of the fuselage box. Make sure F1a is on the same plane as F1b. DO NOT GLUE ON THE TWO SIDE PIECES F1a AT THIS TIME. When the epoxy has cured, CA glue in the 2 F2, F3 and F3a, F4a and 1/16 balsa cockpit floor. FRONT SECTION Find the 4 1/8 balsa laser cut parts that make up the front fuselage sides. CA glue them together making sure they are flat on the building board. Find the 1/32 plywood doublers and glue them to the bottom portion of the fuselage sides. BE SURE TO MAKE LEFT AND RIGHT PARTS! This builder used carpenters glue and weighted them down to be sure they were perfectly flat. This builder also transferred the lines for the K series of stringers on the outside of the right side panel. REAR SECTION Cover the plans with the shipping bag, pin down 1/8 balsa part F9 and layout 1/8 square longerons forward to the position of F5 pin as necessary to achieve the proper curve. Glue in the vertical pieces. Find the 1/8 lite plywood laser cut pieces, 1b and motor mount. This is a good time to pre mount the motor (drill holes, etc.) while the part is easy to work on. Be sure to glue this piece in with RIGHT THRUST side up. Epoxy these two parts on making sure both are square with the right fuselage side. Next CA glue formers F4 and F5, making sure they are square. Glue on the left fuselage side, check for square here, also. Find 1/8 lite plywood parts UG1 and UG2. If you intend to secure the landing gear by lacing fishing line, this is a good time to drill a series of holes in these plates. If not, epoxy them to the When the glue has set, remove from the plan and repeat the process to make another section. Lay the front section down on the plan and glue it to the rear section.

7 Fokker D. V 43 Page 6 When the glue has set, remove everything from the plan and turn the fuselage onto the other side. Slide in the first rear section that you made and glue it to the front section. BE ABSOLUTELY SURE YOU HAVE THE TOP LONGERON ON TOP AND THAT THE F9 AREA IS EXACTLY SQUARE. This will be very important later when you attach the elevator IT MUST BE PARALLEL TO THE WINGS. Make a cardboard template for the cockpit area. Make a part from 1/32 plywood and glue to the fuselage. Add the 5 1/16 x1/8 stringers to the rear section. Add the 5 stringers that go from F1a to F3. Turn the fuselage and put the bottom on the building board over the top plan view. Weight it down and secure it with pins. Pull the two sidepieces in and glue in F8 and F9. CHECK TO BE SURE THIS AREA IS SQUARE. Check that the sides are true to the plan. Glue in F6 and F7 along with their bottom pieces. The above steps are very important to building a straight airplane. This builder made a little balsa fixture 23/16 x25/16 very square and pinned it to the plan in the rear to be sure these parts were square. Find the 2 1/8 balsa F1a side parts and glue them in position, making sure they are on the same plane as F1a and F1b. Glue on K 1thru 5 on both sides. Add the F1c (wing saddle) and F1d parts to each side. BUILDING THE COWL Find the 1/8 lite ply parts C1 and C2 and 1/4 balsa parts C3. CA glue together the C3 parts to make 3 rings. Laminate these together. This builder used white glue.

8 Fokker D. V 43 Page 7 Wrap the plywood pieces around the ring and CA glue one at a time. The last piece will need to be cut to fit the final bay. When the glue has set, sand the plywood pieces flat to both sides of the rings. CA glue the laminated balsa rings to the C2 ring. Do not cover up the 1/8 holes in C1ring. Co nstruction Detail You are going to make a short barrel with parts C1 and C2 using 1/4 square balsa as spreader bars and 1/32 plywood to cover the outside of the barrel. Cut 6 1/4 square x 13/8 long balsa (scrap from leading edge). 1/32 plywood comes in 6 x12 sheets, and the grain usually runs the 12 direction. Cut three pieces across the grain to 11/2 x6, this should allow the plywood to bend easily. On a flat building board, CA glue one spreader bar on the edge of either C1 or C2. Use a square to get the piece square to the edge of the ring and perpendicular to the ring. When the glue has set, bend one of the ply pieces around the ring, centering the end on the middle of the spreader bar. Mark where the other end of the ply falls on the circumference of the ring. This is where another spreader bar is to be glued. Repeat this process around the ring and back to the first spreader bar. You should have a spreader bar at every joint in the plywood pieces. Add other spreader bars where necessary. Be sure all spreader bars ARE SQUARE to the edge of the ring. Make a cardboard template from the plans for the radius on the front of the cowl. Sand the laminated rings to match this template. Cover the cowl in your favorite manner and primer and sand to a smooth surface. This builder used 1/2 ounce glass cloth and polyester resin. Cut 3 1/8 wood dowels to 3/8 long and glue into the 3 holes in C1, extending 1/4. Place the cowl onto F1a on the front of the fuselage and adjust the holes to allow the cowl to fit perfectly. The inside of the cowl can be lightened by carving away (or sanding) the excess balsa from the laminated rings. This builder used 2 sets of mini magnets to hold the cowl in place.

9 Fokker D. V 43 Page 8 LANDING GEAR Bend 2 pieces of 1/16 music wire as per the plan. Note the bend required on the side view of the fuselage plan for the rear wire. Cut an axle from 3/32 music wire. These 3 pieces need to be soldered together. This builder likes to build a fixture when soldering landing gear wires. It allows for an easy and accurate soldering job. Use the plans to lay out where the wires need to be secured and make a cardboard piece to hold the axle in center and the correct position. Tape the axle to this plate, now you can do final bending on the angles to get the wires to stay in position. Wrap the wires with thin copper wire and solder. spokes. Fold the paper along the crease lines to exaggerate the raised lines. Cut one spoke line to the center and overlap to the next spoke line to make a cone. Use white glue to glue it together. Cut a small circle in the center and attach it to the wheel with white glue. The outside cone can be attached at this point if wheel collars are use. Alternately, after installing the wheels on the axle, a washer may be soldered to hold the wheel in place and then the outside cone is attached. This method makes a very scale appearance. TAIL POST The rudder on this model has no vertical stabilized to attach to. For this model we have to secure a 1/2 length of 3/32 aluminium tube to the elevator hinge tube to be the hinge point for the rudder. The hinge pin inside the aluminium tube is also secured to the plywood tail skid for additional strength. Layout the tail skid on the plan and mark the point where the hinge pin hits the tail skid. This builder drilled a hole in the tail skid so as to run the hinge pin up thru the tail skid on assembly. Do not glue the tail skid in position yet. Later you can use the hinge pin to locate the proper position of the skid. REMINDER DO NOT USE CA GLUE AROUND THESE HINGES EPOXY ONLY. Tape the elevator into its proper position. These next steps are tricky; take time to get it right. Thread the hinge pin thru the rudder and the 1/2 tube up to the top of the rudder. Put the tail skid in place with the hinge pin thru it. Tape the tail skid to F8. On the centerline, use a square to square the rudder with the elevator. Tape it all in place. When everything is square, put a tiny drop of epoxy between the 1/2 rudder tube and the elevator tube. Just enough epoxy to hold it in place (let the epoxy cure) so you can wrap it with thread. You will add epoxy LATER to the laced thread area. Find the 1/8 balsa pieces LG1, LG2 and LG3. File a 1/16 half circle in the leading edge (check plans to see which side is leading edge) of each part. Sand the music wire to rough it up then epoxy each part to its appropriate wire leg and axle. When epoxy has cured, sand both leading edge and trailing edges to a round shape. WHEELS Find the wheel parts. Use a brass tube to center the 1/32 ply rim plates on the 1/4 balsa wheel core and glue them together. Glue on the 1/8 ply collars to the outside of the rims. Cut the 3/32 I.D. tube to correct length and glue into the center hole. Massage the Neoprene foam rod into a circle, then CA glue the ends together. Take time to get a smooth joint. Roll the Neoprene tire onto the balsa core. CA glue the Neoprene to the 1/32 rim plate. Use CA glue sparingly, as it really likes the Neoprene. Transfer the spoke cone pattern on the plan to heavy card stock (make four). Cut out the circle. Use a ballpoint pen to score each line on the back to make an impression of

10 Fokker D. V 43 Page 9 shows a small bend at the top where the struts go into brass tubes in the top wing. The small bend is very difficult if the wire is cut to size first. This builder found that by leaving the wire long, this small bend is very easy, and then cutting to size after the bend is made. The tail skid can now be glued in place. This builder laminated 2 pieces of 1/64 plywood on either side of the tail skid for additional strength since a 1/16 hole was drilled thru it. When the tail skid glue has set, pull the rudder hinge pin out and disassemble everything. The rudder should come off with no problem and the 1/2 tube secured to the elevator hinge rod. Remove the elevator from the fuselage. Mark the top of the 1/2 tube, when you reassemble for final assembly you must have the mark on top. Epoxy the laced thread with just enough epoxy to cover the thread. Do not let the following photo confuse you. This builder did not mark the top of the tube. When this photo was taken the tube was in the front of the elevator position. Please visualize it flipped over to the aft elevator position with a mark denoting up. Now is the time to trial fit the cabane struts. You will find that you have to make several adjustments in the bends to get everything to slip into place easily. You will also find that the creator should have given us three hands for a job like this. This builder made a plywood template from the plans that have the correct wing incidence and position of wing leading edge in relation to former F1a. Some work may have to be done on the tubes in the fuselage to get the width of the cabane struts correct. Fiddle around until everything slips into place and the wing is square with the fuselage and wing tips triangulate equally to the tail post. CABANE STRUTS The cabane struts are 3/32 music wire. Bend the music wire as per the plans. Note that the fuselage side view INTERPLANE STRUTS Find the 4 1/8 lite plywood IP struts. Sand to round leading and trailing edges. Soak with CA glue to add some strength to them. Try to keep the tabs at both ends square for a good fit in the wing sockets. TRIAL FIT Time to tape everything together and see how it looks.

11 Fokker D. V 43 Page 10 COVERING If you haven t already started, time to cover this beautiful model. Just a reminder The aileron servos need an extension and Y connector in the top wing before covering. This builder used Polyspan to cover this model. MAKING A SPINNER Do not let the idea of making a spinner scare you. It s not that difficult. You will need some foam (epoxy compatible), some fiberglass cloth and some epoxy. Start by making a 21/2 1/16 plywood back plate. Glue a small length of 1/4 dowel in the center hole. Glue a 21/2 cylinder of foam (11/2 high) onto the back plate. This builder used Dry Foam. This builder used 4 ounce glass cloth against the foam, painted down with epoxy, then 1 ounce cloth on top to fill the weave. After epoxy is cured, sand lightly and apply another coat of epoxy to smooth everything out. After second coat has cured, return to the drill and do the final sanding. Apply primer and sand until you are satisfied. Remove the finished spinner from the foam and back plate by running a pallet knife around the edge of the plywood and down into the foam. When removed, clean out all the foam from the inside of spinner and from the back plate. To make the spinner removable, screw tabs need to be added to the back plate. This builder used x1/4 screws to hold the spinner to the back plate. Make a side view plywood template from the plans and sand the foam to the shape of the template. Chucking the dowel in a drill press or hand drill makes sanding the foam really easy. FINAL ASSEMBLY Place the top wing upside down on the table. Put the cabane struts into the fuselage and turn the fuselage over and put the cabane struts into the wing. Prop up the rear of the fuselage to hold everything in place. If you made an incidence template, put it in place also.

12 Fokker D. V 43 Page 11 Make sure the fuselage is square to the table. Measure (triangulate) from the center of the rear fuselage to each wing tip to make sure they are equal distance. When you are satisfied glue the bottom wings, both at the struts and fuselage joint. Adding the elevator and rudder is a little tricky. If you glued on the rudder hinge tube properly, this assembly won t be a problem. Tape the elevator in position as you did before and put the rudder on by pushing the rudder hinge pin up thru the tail skid thru the rudder tubes. If you choose to not run the pin thru the tail skid then you have to join the rudder to the elevator before you tape the whole assembly to the fuselage. Prop up the tail skid so you can sight through to the bottom wing easily. Adjust the elevator so that it is parallel with the bottom wing. Sighting to the top wing is tricky as the swept back wing won t have a long surface to match. But it is a good idea to check that the elevator matches the top wing at the same spot on each side. Measure from the elevator tip to the bottom wing tip be sure the measurement is the same on both sides. You may have to sand the rear of the fuselage to get this correct. When you are satisfied that everything is perfect, add a drop of CA glue to each brass tube joint. You will find that you have a very stiff connection. Put the interplane struts temporarily in place and fit a bottom wing into place buy first putting the struts in their holes and then joining to the fuselage by putting the spar stubs into the slots next to the landing gear mounts. Tape together at first until both wings are fitted. Use a long straight edge on the leading edge of the bottom wings and triangulate again to the rear of the fuselage. When you are satisfied, glue it together. REMEMBER NO CA GLUE HERE.

13 Fokker D. V 43 Page 12 If you squared the rudder with the elevator before, the rudder will be square with the rest of the model now. CONGRADULATIONS You have completed a very beautiful model of the Fokker D.V. Install the radio system. Balance the model as shown on the plans. This model has a very short nose moment. This builder built a battery shelf that extended beyond the firewall, so that the Li Po battery and lead weight could be as far forward as possible. PILOT A proper scaled pilot interlocking profile was provided with this kit. Slide the front and side profile pieces together. Mark the profile on 4 1/2 balsa pieces. Saw them to shape and glue to the profile (a small scrap of 1/8 balsa will be needed for his chest). Start carving with your #11 blade. After you have a nice face and body, you can cut off the head at the neck and turn his head and also sand an angle on the neck to make him look up or down. Glue his head back on and use some body to smooth out the cut area. This builder built up a scarf from body putty. This is also the time to cut the torso shorter to fit at the proper height in the cockpit. Sand and primer him smooth. You can saw the profile to both sides of the balsa before gluing together. Goggles and shoulder harness were made from heavy card. He was painted and glued into the cockpit.

14 Fokker D. V 43 Page 13 FITTING RIGGING WIRES Use strong thread or Kevlar fishing line or elastic beading cord to simulate rigging wires. Use small screws, fishing hook eyes, straight pins or small eyelets to attach the lines. While not technically required, these wires can add a degree of strength to your model. Finished Model CONTACT INFORMATION Distributed by: Bengtson Company e mail: sales@aerodromerc.com Web Site: FLYING The model should ROG on pavement or hard surfaces. On grass, the model may require hand launching. Be careful that your hand or fingers do not catch on the lower rigging. Launch firmly and level. Initially the tail surfaces and ailerons should not need large throws. Let the model gain altitude slowly off the runway. Applying too much up elevator at slow speeds risks a stall. Make your turns gently as tight turns risk tip stalling in any model. Don t expect the elevator to make the model climb. Think of the elevator as a device to change the attitude of the model. The wing and airspeed ultimately make the model climb. Often down elevator applied at stalling can avoid a major crash. The most important details for proper flight operations are: 1. CG location. Tail heavy models never fly well or at all. 2. Down and right thrust. 3. Straight and non warped wings