Fokker Dr.1 46.7”

Fokker Dr.1 46.7” 1/6 Scale Fokker Dr.1 46.7” 1/6 Scale R/C Scale Model Instructions CONTACT INFORMATION Designed by M.K. Bengtson Prototype by Frank Jaerschky Manufactured and Distributed by: Bengtson Company e‐mail: [email protected] www.aerodromerc.com
Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 1 I like to use yellow aliphatic glue. It gives me time to correct mistakes. Makes for a slightly longer build than if I used CA, though. Fokker Dr.1 1/6 Scale Thank you for purchasing the Fokker Dr.1 1.6 scale model for electric flight. THE MODEL Finished Model by Frank Jaerschky This model is designed to be easy to build and exciting to fly. This manual is a distillation of Frank’s comments in building the prototype. SPECIFICATIONS More than 470 laser cut parts Scale: 1/6 Channels: R/E/A/T Wingspan: 46.7ʺ Wing Area: 737 sq in Weight: 76 oz
Power System: AXI 2826 direct drive brushless outrunner Prop: 14x7 Wheels: Balsa & plywood, Neoprene foam tires Airfoil Type: Flat‐bottomed scale Cowl: Built up balsa and plywood Spinner: N/A Covering: Balsa and Litespan or Polyspan Prototype Builder: Frank Jaerschky The following is taken from Frankʹs comments in building the model: FUSELAGE Assembly starts by gluing together the two 3/16ʺ parts that make the left and right forward fuselage sides. There are precut slots and holes for bolts and formers, so make sure you open them up. A little sanding with a block ensures the fuse sides are nice and flat. At the risk of sounding like trying to tell people how to suck eggs, label a Right and Left fuse side, along with the respective 1/32ʺ ply doublers. More than once Iʹve admired my craftsmanship on two very identical, right sides. I also like to mark a series of parallel lines on the inside of the fuselage sides. These come in real handy later when it is time to line up servo mounts, etc. It only takes a minute, but it really is worth the time. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 2 The rear of the fuselage is built up from 3/16ʺ sq. sticks and 1/16ʺX3/16ʺ strips. In retrospect, I should have done this step before adding the doublers. I like to build both sides one on top of the other (separated by plastic wrap or wax paper) to make sure they are identical. With the doublers, I will have a 1/16ʺ gap between the balsa sides if I lay them on top of each other. Iʹll just make a temporary 1/16ʺ spacer to go between the sides. Doublers test fitted. Sides marked L and R. Parallel lines will be carried on to doublers when glue is dry. The rudder assembles easily with laser cut 3/16ʺ sheet pieces and the supplied 3/16ʺ sq stock. The stack, waiting for glue to cure. The fuselage is coming along. After building the rear framework, I sanded everything nice and flat. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 3 The front end of the fuselage is formed by interlocking plates and formers, and makes for a very strong front end. Strong enough that I think this airplane could easily take a .56 4‐stroke. (Sorry, I can hear the boos and hisses. Just thought Iʹd throw that option out there for those that are still so inclined). The balsa cross members were cut to length from the top view, and then glued into place. Again, the square was used to make sure everything stayed aligned. The top formers were then glued on top of the cross members. The forward side fairings are 1/32ʺ ply, with a 1/8ʺ balsa sheet piece running down the middle to ensure the correct taper. The ply side fairings go on easily with a bit of water to make them more pliable, and a few pins. Also note that the 1/16ʺ balsa turtle deck sheeting and the 3/32ʺ balsa cockpit floor are now in place. Starting to look very Dreideckerish! The fuselage is now joined at the tail. I pinned the fuse down over the top view, and then blocked up the nose and tail to keep it from rocking. A square slid up to the outline of the fuselage on the plan is used for alignment. If the vertical leg of the square just touches the edge of the longerons, you know youʹre ʺOnʺ. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 4 glued to one frame, and then the other frame is glued to that. These frames are then sheeted with 1/32ʺ ply. Frames and spacers. Larger frame on the right is the rear of the cowl, and actually forms part of the middle/upper wing retention system. Airfoil shaped fairing to which the covering will be attached, allowing the lower wing root rib to sit flush against the fuselage side. Building the cowling starts with 1/8ʺ lite ply front and rear frames. These frames have 1/4ʺ square holes laser cut which accept laser cut 1/4ʺ balsa spacers. The spacers are COWL The ply sheeting is supplied in 3 pieces. Instead of butt gluing the sheeting, I sanded a bevel on the sheets where the join so that they could overlap a bit and form a scarf joint. Once sanded, this will be a bit stronger and cleaner than a butt joint. Start with the top of the cowl. First, draw a line across the middle of the short length of one of the pieces of sheeting. Trial fit the sheeting on the cowl frames, centering the line above the top cowl spacer. Bend the sheeting around the frame, and use a pencil to mark the extent of the sheeting so you know where to apply glue. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 5 Apply glue to the frames, and lay the sheeting down on top of the frame. Pin it down at the center first, and then work out to the ends of the sheeting. Let dry. Now finish sheeting with the other two pieces. A note on choice of glue when using thin ply. Thin plywood soaks up CA glues like a sponge. Once the glue hardens, it makes the ply very hard to sand. You will wind up with uneven sanding between areas hardened by glue and those that are not. For that reason, I suggest using aliphatic glues. Takes a while longer to dry, but it will be much easier to sand and finish. The front of the cowl is formed with 1/4ʺ balsa sheet pieces, and then the cowl is carved and sanded to shape. Iʹll do that later. DUMMY MOTOR The Axi motor mount is part of the dummy rotary engine. Itʹs quite the piece of work. The dummy crankcase is composed of layers of laser cut 1/16ʺ ply, 1/8ʺ lite ply, 1/8ʺ balsa, and 1/4ʺ balsa. Each part has 3 holes laser cut through which motor mounting bolts will pass. When gluing the parts together, pay attention and make sure these holes are always aligned. Also, assemble the pieces so that the grain alternates for added strength. Now I suggest you count, count, and recount how many layers of 1/4ʺ balsa it takes to make the crankcase. You will find it takes 6. Notice that there are 8 pieces supplied. Take two of them and put them out of reach, so you will not be stupid enough to use all 8 and wind up with a crankcase that is too long. Should that happen, you can use a razor saw and remove the offending piece. Should you still not be able to count, you can reach for the razor saw and repeat. Study the plan and make sure the pieces are assembled in the correct order. Note that there is a 1/8ʺ balsa piece in the middle with extra notches. These are for the dummy cylinder construction later. The plans say to make a channel to pass the motor wires through, out the back of the crankcase. This is certainly do‐able, but I decided to make a hole at the top of the Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 6 crankcase and will route the wires outside the crankcase and then back through the firewall. This way, there is no chance of a wire interfering with the rotating can of the motor. Iʹm pretty sure the assembly is quite strong enough as it is. But I think I will line each hole with a length of brass tube. Iʹm afraid that I may get a bit ham fisted and over‐tighten the bolts, crushing the balsa if the tubes arenʹt there. The front face of the crankcase is hard ply, and the rear edge is 1/8ʺ lite‐ply, but Iʹd rather be safe than sorry here. I spent some time on the cowling. There are 3 layers of 1/4ʺ balsa, followed by the 1/4ʺ balsa faceplate. Time to for some sanding. The front of the crankcase is made up of 2 layers of 1/16ʺ ply that is laser cut to fit the Axi motor, including cooling air slots. The motor is screwed to this plate. The whole assembly is held to the firewall by 3, 2 1/2 inch 4‐40 bolts that run through the crankcase and bolt into blind nuts in the firewall. Small plywood laser cut spacers between the crankcase and the firewall (not shown in photos) set the down and right thrust. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 7 thread. The cylinders are made up of a piece of 1/8ʺ sq balsa, and some other laser cut balsa disks. The disks are glued to the square piece, and then the supplied pre‐
printed card stock is wrapped around that assembly and glued in place. Then the cylinder is glued to the crankcase. Iʹm going to do as the plan suggests and use the twin carpet thread technique to simulate cylinder fins. Once painted and highlighted, they will look great. Itʹs always a good idea to install blind nuts before the part is glued in place and you canʹt get at it. Seems I forgot that little piece of advice with the firewall. The firewall takes 5, 4‐40 blind nuts for cowl retention, and motor mounting. Luckily, there is a big hole in the front of the firewall that I could still squeeze a C‐Clamp through, and together with some scrap ply pads to protect the firewall, I was able to press the blind nuts into place. Iʹve started on the included dummy motor cylinders. The crankcase has already been described earlier in this I have often heard of the mysterious ʺLost Thread Methodʺ of simulating cylinder fins, but was never really sure how to do it. The plans suggested this method, so I Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 8 gave it a try. I just used a spool of some nylon kite string that was lying around. The photos and captions tell the story. Itʹs a great method. The end results are quite good I think. When painted, the cylinders should look very convincing. And the process goes quite quickly, too. In case youʹre curious, each cylinder took about 42ʺ of thread, so thatʹs 9X42ʺ=31.5 feet total. Luckily, you can reuse the ʺspacerʺ thread, if youʹre careful. Put a small drop of thick CA on the cylinder. Lay both threads in the glue and let harden. Start wrapping the threads around the cylinder. Make sure the threads stay parallel and do not cross each other. Keep the wrappings snug against each other. When you reach the bottom, put another small drop of thick CA on the cylinder and secure the threads. Trim both ends of the threads. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 9 Trim off the end of 1 of the threads. Try and keep the ends of the thread on the same side of the cylinder. You can face that side of the cylinder so that it canʹt be seen when complete. Gently pull the other thread out of the Ca. Unwrap that thread from the cylinder, being careful not to disturb the other thread. When you reach the end, gently pull the thread out of the glue. Soak the cylinder and thread in thin CA. Time for paint! MID WING MOUNT The cowl mounts with 2 4‐40 bolts. There is a slot in the back of the cowl that engages the tab on the front of the middle wing mounting plate. That is what holds the middle and top wings on. This results in an invisible wing mounting system. I think there will be enough room between the front of the cowl and the back of the prop so that you donʹt need to take the prop off every time you put the airplane together at the field. Moving the cowl 1/4ʺ forward will be enough to release the wing. The middle wing mounting plate sits flush inside the fuselage. There is a tab at the rear of the plate that slides into a slot in the fuselage former. The front tab is held down by the cowl assembly. Formers are glued to the top of the pate and then sheeted to match the top curve of the cowl. The triangular wedge on the rear former is just temporary. I canʹt sheet that portion until the wing is attached to the plate, and I would be sure to break the former off without the extra reinforcement. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 10 So the designer and I scratched our heads about this for a while. In the end, we decided it would probably be best to have a slot in the lower cowl lip underneath the prop shaft hole. To hide the hole, I cut a wedge out of the cowl, and used magnets to hold the wedge in place. My fix looks a bit sloppy because I only had 1/4ʺ magnets on hand, and the cowl face is 1/4ʺ balsa. Trying to make a 1/4ʺ hole in 1/4ʺ thick material is not easy! In any case, it worked out OK, and once the cowl is glassed, primed, and painted, it will look fine. During the build, a problem arose with regards to the fit of the cowl. It turns out what looked great in 2 dimensions didnʹt translate into 3 dimensions very well. It is very hard to judge these things until the parts actually all come together. As mentioned before, the middle and top wings are retained by tabs on a mounting plate, and the front tab is held down by a slot in the back of the cowl. The cowl is held on by 2 bolts through the rear frame and into blind nuts in the firewall. So the cowl must come off every time the airplane is taken apart or put together. All sounds good, but I found that when the AXI and the dummy motor are bolted on to the firewall, the cowl doesnʹt fit anymore. There is not enough clearance between the front face of the cowl and the motor shaft to allow the cowl to go on and off. Another way to fix the problem would be to eliminate all but the bottom 3 or 4 dummy cylinders, and then cut away a larger portion of the back of the cowl. That way, the cowl could slip right over top of the dummy motor and prop shaft. But then you would need to remove the prop every time you took the wings off or put them on, too. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 11 Just a note ‐ there is a lot of sanding to do to get the cowl to the right shape. To make it easier, I made a template out of a piece of meat packing foam so that I knew when I had reached the right shape. Cowl has been glassed with 0.75oz glass cloth and Z‐Poxy finishing resin. Just for curiosity sake, I want to see how much weight some cloth, resin, primer and paint add. Before glassing, the cowl weighed 61g (2.15oz) All glassed, and weighing in at 64g (2.26oz). The next steps will go something like this: prime, sand, prime, sand, prime, sand, paint. The photo exagerates the appearance of the removable wedge. Iʹm actually very happy with the way it is turning out. Once the cowl is painted, I think the part line will be very hard to see, especially as the cowl will be black. Just a couple of shots of the cowl and primer. Picture #1 shows the cowl with 1 coat of primer applied. I use Motomaster brand ʺPrimer & Scratch Fillerʺ, available at Canadian Tire. (If you arenʹt Canadian, Canadian Tire is like a Menʹs dream department store with loads of cool guy stuff, and enough boring stuff to keep the women happy, too. And yes, they sell tires). Photo 2 shows the cowl after sanding. Not much primer left, but thatʹs the idea! You need to sand off as much as possible, so that the primer only stays in the low spots. Not doing that will only increase weight and detract from the evenness of the final paint finish. The primer really should be wet sanded. So that means being careful not to flood the cowl with too much water. I put some thin CA on exposed wood, so hopefully it wouldnʹt soak up water. Seems to be working OK. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 12 Two more coats and sanding then paint. Once I had the cowl all sanded and ready for paint, it was my full intention to add some simulated rivets using white glue and a syringe. Then paint the cowl. Once the paint had dried, I sanded it down with 400 grit paper, used wet. Then I applied the rivets. Now I just need to wait a bit for a dry day to some paint on. WINGS Eventually with a triplane, you gotta build some wings. So Iʹve started with the lower ones. The main spars are 3/16 X1/2 balsa. The trailing edges are laser cut 1/32 ply, with the TE scallops laser cut. The distinctive Dr1 ʺSaw Toothʺ leading edge is laser cut from 1/32 ply. There are laser cut 3/16ʺ pieces that go on top of the forward main spar between the ribs. So when adding the ribs, itʹs merely a process of working from one end to the other, adding a block, a rib, a block, etc. The ply LE sheet is then glued to the tops of the ribs, fitting nicely into the laser cut notches. I suggest then adding the leading edge, and gluing it securely to the ply LE sheeting. This gives more support to the ply when you take the tip of each triangle and bend it back to glue down onto the spar blocks between the ribs. Wetting the sheeting helps, too. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 13 Tab at rear of mounting plate fits into slot in fuselage just forward of the cockpit. The root rib has 8‐32 blind nuts installed to fasten it to the fuselage. There are also 5/32ʺ brass tubes along the spars for the first few ribs. There are two 1/8ʺ music wire joiners that run through the fuse and into these tubes. (Although Iʹm thinking of maybe using carbon fiber tubes to save some weight) Slot in rear of cowl goes over the tab at the front of the mid wing mounting plate. Middle wing is attached to mounting plate with 4‐40 bolts and blind nuts installed in mid wing. Cowling is secured with 2, 4‐40 bolts and blind nuts installed in the firewall. When the dummy motor is in place, the bolts are still easily accessible between the cylinders. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 14 Ailerons are built up from balsa and ply. The ribs are 1/16ʺ ply for strength. Construction of the upper wing has started. At this stage,you start to get a real sense that this is a large airplane in three dimensions. My building board is a 48ʺ ceiling tile, and with a 47.5ʺ wingspan, it fills the board from end to end. The cabane mounts are at their scale location. They consist of ply with blind nuts. I used slow set epoxy to make sure this all important joint doesnʹt fail. The wing gets bolted to the cabanes using nylon landing gear struts and 4‐40 bolts. The sheeting around the middle wing and its mounting plate looks a bit tricky, but itʹs not that bad. There is some nice scrap balsa from some of the laser cut part sheets that is perfect for the job. To make sure everything will look good when Iʹm done, I put the wing in position on the fuselage, and put some plastic wrap between the fuselage and the back of the middle wing to make sure they didnʹt become permanently attached. With some trial and error, I cut a piece of balsa as wide as I could so that it would sit on top of the mid wing sheeting, and also bend down along the formers. After soaking the sheeting, it became very pliable, and using pins and glue, it was nailed into place. Itʹs pretty amazing the contortions that the correct type of balsa will twist into The portions near the leading edge I will finish off with gluing in some scrap soft balsa, and then using filler. Iʹm not one for making templates to try and get it right. I tend to sheet first and ask questions later By the way, the square block beside the hole is the rear cabane mounting block. The hole is there for the servo wire Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 15 The landing gear is made of 1/8ʺ music wire. After bending the struts, I mounted them in place on the fuselage. The best jig is the actual airplane, after all. The axle is then laid on top, and everything gets bound together with soft wire before soldering. To get a good joint, clean the wire well with emery cloth, wrap tightly with soft wire, then apply flux with a brush. I use a Weller 40W iron, and it gives plenty of heat. Touch the iron to the assembly, let it get good and hot, and let the solder flow into the joint. The final result is tough as nails. I worked on the cabane struts this afternoon. They are made from 3/32ʺ music wire. The top wing is attached to the cabanes with 1/8ʺ nylon landing gear straps and 4‐40 bolts. The bottom of the front struts slide into a 1/8ʺOD piece of brass tubing that is built into the middle wing mounting plate. The bottom rear of the cabanes have a ring terminal soldered to them, and that gets fastened with a screw into the rear mounting block installed in the middle wing at the rear spar. Interplane struts are a lamination of 2 1/16ʺ ply outer pieces and a 1/32ʺ ply inner piece. The inner piece has a Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 16 relief notch cut in it that ensures correct position of a DuBro landing gear strap. The landing gear strut fits into the top wing in a rib also made out of 2 1/16ʺ ply and 1 1/32 ply pieces. Landing Gear strap in position. I must admit I cheated with the struts. It is absolutely essential that all 4 pieces of the cabane struts be the correct length, and have all the correct angles. Because of this, I felt I would have trouble making my bends accurately enough to do the job. So, after roughly bending and sizing each strut, I cut it in half and then chopped about 1/8ʺ off one half. Then I slipped a 1ʺ long piece of brass tubing over the strut, and joined it together again. The interplane struts slide through a passage in the middle wing. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 17 Once I had the top wing in place and resting on top of the interplane struts, it was easy to adjust the length and angles of each of the cabanes, and then solder the two pieces back together again. The fit of the interplane struts is really first rate. The alignment and incidence was bang on what is shown on the plans. glue the neoprene cording together to from a “tire”. Use thin CA sparingly as the CA bonds very aggressively to the rubber. Press the CA wetted ends together for an instant bond. The best way to align the ends is to glue them while they are in place on the wheel. Then attach the tires to the wheels and CA in place. A thin bead of CA around the rim makes for a secure tire. Paper cones are cut out. Use a ball point pen to score each line on the back to make an impression of “spokes” It is helpful to do this operation on a paper tablet so that the pen makes a good crease. Fold the paper along the crease lines to exaggerate the raised lines. One of the sections forming a wedge is cut out. Make cuts to the center of the circle along a pair of the spokes. Close the paper cutout to form a cone and tape the joint inside the cone. The inside cones may now be attached to the wheels. The outside cones may be attached at this point if wheel collars are to be used. Alternatively, after installing the wheels on the landing gear, a washer may be soldered to hold the wheel in place and then the cone is attached. This method makes a very nice scale appearance. WHEELS Gluing the ply sides on the 3/8” balsa core makes the basis for the wheels. Use the brass hub for alignment. Epoxy the hubs in place and add a sufficient amount of epoxy around the base of the hub to reinforce the connection of the hub to the ply. Plywood reinforcing hubs are provided that are to slip over the brass tubing as shown. Next, CA UNDERWING I think Anthony Fokker designed the landing gear wing just to drive modellers crazy. Itʹs a big surface with a narrow mounting area, and in a position where it is bound to receive a few blows. With that in mind, I wanted to make sure the wing was mounted securely to the undercart struts, but not so secure that there was no give. The bottom of the LG wing is 3/16 balsa. At first I thought that this was way to heavy, Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 18 and that I would make a new one out of thinner material. With my trusty scale in hand, it turns out that the supplied wood was quite light, and that going to thinner wood of medium quality wouldnʹt save any weight. The ribs are laser cut 1/8ʺ and 1/16ʺ. The thicker ribs go on the outside, and next to the wire struts. The thinner ribs go in the middle. The next to last outermost ribs are glued in at an angle to match the the wire struts. I used silicone rubber to glue the ribs to the wire, and CA to glue the ribs to the bottom. Iʹm hoping that the silicone will offer a bit of flex in less than perfect landings. I also made some tabs out of brass sheet that I soldered to the axle. I then epoxied the tabs to the base. The brass has just enough flex to allow a little wiggle. I sheeted the top with 1/16ʺ balsa. I also made the holes a little over sized in the top sheeting where the wire passes through. If the sheeting is right up against the wire, any wiggle will crack the sheeting. WING SERVOS Hereʹs the aileron servo installation. I chose the lazy man method and used silicon rubber to glue the HS‐81ʹs into their location. Clean and easy, as long as nothing goes wrong with the servos later. Then surgery and patching is required. The wires run inside the wing to the cabane struts, and then out a precut slot, and down the cabane strut, through the middle wing, and into the fuselage. Iʹm hoping to be able to disguise the wire with the cabane struts so that they are unnoticeable. The top and middle wing form a complete unit once the airplane is done, so there is no need to have the wires flapping loose between the two wings. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 19 COVERING Covering has started. I love covering, call me crazy. Iʹm using Polyspan attached with Stix‐It. A few coats of nitrate dope to seal, and then colour dope for the final finish. I have started covering the fuselage. I was worried about this, as there are a few tricky areas, namely the area between the lower wing root and the fuselage side. It actually came out very well, I think. Iʹm starting to think I can make Polyspan do anything. Just look at the sexy curves it has molded itself to at the front of the fuselage, from the firewall back to the trailing edge of the lower wing. Great stuff, polyspan. I donʹt know how I ever did without it! The lower wings are covered and have one coat of nitrate dope on them. The sawtooth ply leading edge should look great when the wings are covered and painted. And hey, the wingtips came out with minimal wrinkles! Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 20 SPANDAU MACHINE GUNS The kit includes balsa parts for making the twin Spandau machine guns. There is a pattern on one of the plan sheets for the cooling jacket. I scanned the pattern into my computer, then used Photoshop to darken the colour a bit. I then printed the patterns out on 4X6 photopaper. Then itʹs just a matter of cutting them out and wrapping them around the balsa assemblies. CABANE STRUT FAIRINGS The kit includes laser cut pieces of balsa to make cabane strut fairings. I glued the fairings to the wire with thin CA. I then brushed a coat of Stix‐It on the fairings, and covered the fairings with polyspan, wrapped around the wire strut. This should make things pretty strong. I am going to do the front fairing after the model is completed and the upper wing is joined to the middle wing. I hate, hate, hate servo wires flopping in the breeze. So my plan is to attach the wings to each other, glued the balsa front fairings on, then glue the servo wires along the inside of the fairing. Then Iʹll wrap everything with Polyspan, and paint. That should make things invisible. The wires will run from the bottom of the strut into the fuselage, so they should be pretty hard to see. The model does have pre‐cut holes in the middle wing ply sheeting to allow a more direct run for the servo wires into the fuselage for those who are more sane than I. Here are the finished Spandaus. I drybrushed some silver over them for a bit of weathering, just to break up the monotony of the flat black. My original plan for running the aileron servo wires didnʹt work out. So I had to revert to what the designer had in mind. I glued the servo cable to the inside of the rear cabane strut fairing, and then painted everything to match. The wires go through a hole in the middle wing, and into the fuselage. I still need to add a bit of olive drab Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 21 to the wires to hide them a bit where they run across the fuselage. In this view, rudder on the left, elevator on the right. PILOT FIGURE The kit includes two pieces of laser cut balsa in the form of a side and front profile of a pilot. The plan sheet says ʺʺGlue together, fill with foam, and paintʺ. Heck, if itʹs that easy, I might as well give it a try! Iʹm using blue foam, as it seems to be much easier to carve with a hobby knife and sandpaper than white bead foam. Once I get the pilot to shape, Iʹll probably give him some sort of paper mache finish, and then add details like buttons, helmet, etc. Iʹll probably give him goggles to avoid doing the eyes. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 22 It looks like the wrinkly leather trick will work out well. I also wanted to add a fur collar for those cold missions over the front in pursuit of der Englander. I used a pencil to mark out where I thought a fur collar would go. Then I used a bead of spackle and a small spatula to get the shape. I then used the end of a coarse bristled paint brush and stippled the spackle. When itʹs dry and painted, I think it will look good, too. I didnʹt think that Iʹd be putting this much work into making a pilot, but this is fun! Frankenflyer continues to take shape. I found that with a new knife blade, the foam is really easy to carve. A small rapid back and forth motion lets you cut very thin slices, making it easy to shape. After basic carving, I used water based spackle to fill any voids. Then I sanded to shape with some 220 grit paper. I then covered him with small patches of tissue paper and a white glue and water mix. Itʹs a good idea to tear, not cut the tissue paper to size. Tearing gives nice feathered edges that blend well. Cutting leaves sharp edges that will stand out. I used the end of a stiff paint brush to wrinkle the wet paper. Iʹm hoping that when it is dry and painted, it will give the effect of a wrinkled leather coat. Iʹm doing the red/white/black fuselage band. Iʹm using spray paint, so that means lots of masking. I like to use dollar store black electrical tape for masking. Itʹs cheap, goes around corners, leaves a nice clean edge, and removes well without lifting off the paint underneath. Iʹve started with the white, then Iʹll add the red and black one by one as each color dries enough to allow further masking, about 24 hours per color. Takes a while, but itʹs worth it in the end. I also use lots of tape and newspaper to prevent over‐spray. It takes about 45 minutes to do the masking, and then 45 seconds to apply the paint. Iʹm using Krylon ʺFusionʺ right out of the Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 23 of the hatch. Once the hatch is in place, the basswood piece stops the battery from sliding backwards. Itʹs simple and seems really effective. Iʹve shaken the plane up and down, and the battery shows no signs of shifting. Pictures were hard to take due to the confined space. Another plus of this design is that with the middle/top wing assembly off and the bottom hatches off, it is super easy to get at the innards of the airplane. spray can. Fusion is meant for plastics, so Iʹm hoping that means it is designed to be more flexible than ordinary enamels. If you havenʹt tried them before for trim painting, give them a whirl. They have a great fan pattern nozzle, and cover really well. BATTERY COMPARTMENT Iʹve figured out an easy way to retain the battery. I built a shelf with an ʺLʺ cross section that I installed cross ways at the front of the fuselage butting up against the firewall. I glued some 3/16 sheet against the inside of the firewall so the battery doesnʹt rub up against the motor mount blind nuts. The battery slides in through the forward most hatch, and the top of the pack is retained by the ʺLʺ. (the shelf will also serve as a place to mount the ESC and RX). The bottom of the battery rest on the forward landing gear mount. I then glued a piece of 1/8ʺ basswood to the inside Weight as you see it in the pictures is 59oz. I figure flying weight will be around 72oz, for a wing loading of 14.26oz/sq ft. Not too bad for an airplane of this size. Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11 Fokker Dr.1 46.7” 1/6 Scale Page 24 FLYING Here are some excerpts of Franks Maiden flight report: “I just got off the phone with the designer to say what a sweet flying Dreidecker AerodromeRC has designed! This one is a real keeper. There was a hint of wind today, probably about 45 degrees on the airplaneʹs nose, so there was a bit of cross wind. I advance the throttle slowly and the tail came up almost immediately. The rudder was very effective right away, and I fed in a bit of right rudder to keep her straight. By the time I had the throttle at 75%, she was up and flying. I needed to dial in some right and up trim, and once she was trimmed out and at a good height, I was able to settle my heart down and concentrate on the airplane. She is a real delight to fly. Very light and responsive on the controls. There is heaps of power available. Full throttle results in a 45 degree climb. The sweet spot seems to be just over half throttle. Flying speed is nice and realistic at that setting. I found the airplane to be fairly stable. A bit of opposite aileron to roll out of turns helps. For my first landing, I kept the speed up and it was a bit hot at touch down. Still, a nice wheel landing and roll out with no nose over. Lots of battery left after only 6 minutes, so up we go again. This time I advanced the power more rapidly, and it leapt off the ground in no time and pointed her nose up and kept on climbing. The next 2 landings ended in nose overs. I landed too fast, and when the triplane starts bouncing down the runway on the roll out, it will eventually find the right bump that flips her on to the nose. No damage at all, thought. The next 5 landings I was confident enough to slow her down much more. It floated right in to a nice nose high landing with a very short roll out and no nose over. As I mentioned before the controls are very responsive. I was very glad to see that the elevator remained effective at low speeds and high angles of attack. My previous 1/4 scale Dr1 lost elevator effectiveness in those conditions, resulting in nasty habits close to the ground. No hint of that with this airplane. The only downside to this morning is that I was flying solo. The pictures here were taken once I had the airplane trimmed out, flying with one hand and aiming the camera with the other. I got some video by placing the camera on a fence post and zipping back and forth a few times. Not too thrilling, but proof the airplane does fly. Iʹll post that later on today. So to sum up, Aerodrome R/Cʹs 1/6 scale Fokker Dr1 is a winner! It looks fantastic on the ground and in the air, and it is a very sweet flying tripe. Thanks for letting me do the proto!!! “
CONTACT INFORMATION Distributed by: Bengtson Company e‐mail: [email protected] Web Site: www.aerodromerc.com Copyright© 2007‐11 M.K. Bengtson All Rights Reserved Rev 07/11