Hello my friends, finally we meet again for you who new here, my name is Julius I make RC model planes and share with you build video and plans in every 2 or 3 weeks in this episode I'm going to share with you how I build this, Cessna 337 Skymaster or in this case is the military version this is O-2A Skymaster or Oscar Duece it was use by US Air Force for recon and to find insurgents in the forest because this plane can fly slow and low also to direct artillery fire and direct rescue mission also can function as a close air support firing its own weapon and can carry rocket launcher gun pods like this the weight of this model is about 2kg or 2000 gram the wingspan is 1800mm it has a unique propeller configuration this is, puller and pusher actually I already made this type of plane two times before and also actually the first model plane that I made was Cessna Skymaster you can see on this clip and the second one is for FPV this..
On the video but on both models, I only have the motor on the back side just pusher so I think this is the first time I make Cessna Skymaster with twin motors like this this plane haven't fly yet I will fly it tomorrow on maiden flight, I hope it can fly and there's no trouble ok guys, let see how I make this model check this out bend and curve the foam board by heating it with a heat gun and then rub and slowly bend it to a metal pipe like this for airfoil formers I use PVC foamboard you can also use 3mm plywood I use PVC foamboard because it's easier to cut although it's a bit more expensive compare to the plywood place the airfoil formers on the foamboard 5mm from the front edge sand the foam board using rough sandcloth to have slope shape like this on the leading edge do the same for the trailing edge as usual I use 80 gram gsm plain paper for making the housing for 10mm carbon tube apply CA glue to make it hard and rigid insert the carbon tube housing inside the wing formers now I am making the airfoil former for the side wing glue the carbon tubes to the airfoil formers make sure one carbon is longer for easier assembly do the same as the middle wing for leading and trailing edges of the side wing attach the foam spars according to the plans make sure to reinforce every hard spar with 5mm foamboard add a piece of 9mm plywood on the inside of each formers to receive locking screw and then make a hole for the screw driver like this I use gypsum or wood screw like this angled the screw so it can be reached and tighten with screw driver from below you can see here, I made scoring lines for easier bending on 5mm foamboard make the score line's interval as narrow as possible for smooth curving add foamboard to the hard spars glue the upper wing part start from the leading edge first using hot glue and then apply foam-safe glue on the spars and formers and then wait 5 minutes before closing the wing now close the side wing make wingtip with 4 stacks of 5mm foamboard for smooth result, sand it with water cut the aileron using a guide from the plans and then prepare the aileron like this add a piece of foam inside the aileron to receive control horn install aileron servo to the wing I use 9 gram micro servo follow these steps to build twin boom tail attach 10mm carbon pipe to the foam boom I suggest you to use full boom length carbon pipe tail boom will be attached to the center wing so here I combine both center wing parts make tube housing again with the same technique as before for the boom and then attach it the bottom of the center boom according to the plans reinforce it with foam strips like this mark the correspondent boom with the housing attach hard point from PVC foamboard to the back of the boom tail you can also use 3mm plywood prepare the horizontal stabilizer like this add former to make a transition part from the boom to the center wing here I use 10mm EVA foam and sandwiched it with 3mm PVC foamboard for making lock system for each boom add mica plastic to protect the foam here how I make the main landing gear the real one is retractable, but it will needs more weeks if I make it retractable the white material is PVC foamboard you can replace it with 3mm plywood I continue making the fuselage formers I removed more than 1/3rd portion of the landing gear base from the original to safe weight I start attaching the foamboard part you need to sand the edges to fit with other parts here how I make the front landing gear by following the plans this is 2.5mm bicycle wheel spoke wire this is 3mm motorcycle wheel spoke wire I also made 2 housing from paper here I add smaller wire for its steering arm and then install it to the fuselage add bamboo chopstick to hold rubber bands for suspension and here how I install the servo for steering the wheel now close the formers with foamboard install the front motor according to the plans in this puller pusher prop configuration we don't need to add motor thrust angle because each prop already cancel each other torque here I use twin DXW 3536 1200kv brushless motor and 50A ESC with 3S 2200mah lipo battery here I try to follow a suggestion from one of you to make score lines with fork thank you Mr.
Cheeseman it worked make engine cowl with 7 stacks of 5mm foamboard and then carve into shape and wet sand it setting up wiring for servo I use white color packing tape for covering cover all surfaces cut the tapes in small cuts for covering curved surfaces the tapes must end up sticking to other tapes but if it stick to the foam you need to add hot glue, so the tape can stick properly use guides from the plans to cut a portion of the center wing you need to sand the tape covering before applying paint I will cut windows on this side so I need to sand it first because it will be harder to sand if there are already windows there use guides from plans to cut windows here I add reinforcement with PVC foamboard to the existing support frames I also add some foam to the frame for receiving the wing glue the center wing to the fuselage here how I finish the top part of the fuselage I use card paper to cover gap on the center wing and add small screw to lock the battery hatch how I cut the landing light on the wing but no light system I use Diton Executive Gray spray paint for primarily color here I use wet paper for masking because you can't use masking tape on it the tape will peel off the paint I will use sticky tape to attach the window glass and use it as a maintenance window here I add paper masking tape around than 2 windows so that way the paint wont peeled off when I remove the glass I use black cable for installing the windshield here I cut the windshield from a curve mica plastic sheet how I curve the plastic you can watch it on Piper Seneca build video but instead of using a helmet as a mold I use R2D2 head make sure add instrument panel first before attaching the windshield I use painted vinyl sticker for adding list and window frame here how I attach window glass apply the printed vinyl sticker decal adding some details as you can see here the wing strut loose from its place that's indicating that the center wing is deformed when I hold it in the air looks like I need to make a functional wing strut not just as accessories so I cut holes on the fuselage and the wing to expose the formers and glue the strut to them I use 2 stacks of 3mm PVC foamboard as the strut material I use servo arm for the control horn the CG is 9 cm from leading edge fortunately the damages was not too many both props were okay the right wing broke and the left tail boom broke but still can be repaired ok lets see what the heck happened there it happened so fast, I didn't realize the steering wheel was not straight so it's steered slightly to the right like this ok, on here this plane was able to take off smoothly that's a relieve, it can fly but here, it looks like when I ease the elevator this plane was diving down and hit a bush here I made one axis gimbal for my Runcam camera I also include it on my plans you can check that out at first I wanted to calibrate the steering so it can take off run in a straight line but then again the front landing gear collapsed and I didn't full check the front landing gear after the crash yesterday after an emergency repair only with CA glue, it's ready to take off again after it hit the first grass patch the front wheel broke again but the plane continue to take off apparently the right wing that broke yesterday was not back to its original shape it bend abnormally but that was not the real problem now the problem keeps diving down [does the wheel folded] I have to hold the elevator up all the time I think I have found the design mistake here that make the plane always nose down the black line is the movement of the plane straight forward like this and the wing has a positive angle of incidence the yellow line but I attach the boom at the same angle as the wing that cause negative pitch to the horizontal stabilizer that made the plane always dive down so I need to re-attach the tail boom and here I re-attach the tail boom now the twin boom already have the correct angle I already change the angle on the plans so you just have to follow the plans I also change the design of the front landing gear that first design was a mistake now this is good ok guys, on 3rd attempt finally this plane can fly and meet my expectation it can…
Easy to take off the power is enough more than enough I think and the control is like other planes but it's not perfect because the wing flex too much and the construction of the landing gear is not strong enough no actually is very weak What I learned on this build is by using a PVC foamboard is not strong enough and also not rigid enough because of this, on the next episode I think will back to using plywood 3mm, again as you can see I made a modification on the tail boom I already change it on the plans so you don't have change it again you just have to follow the plans on the first days after this video is released maybe you will encounter that the link of for the plans is not available yet I will update the link maybe in one week and okay this plane is already finish you can make it yourself by following the plans and the next model, I will continue making part 3 of Boeing 747 the tail section ok guys thank you for watching if you like this video consider to subscribe hit the like button and also share the video to the..
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