Simon Chaddock Posted January 21, 2010 Author Share Posted January 21, 2010 One more evening and the bits can be placed together to see what it will look like. The cabane struts will be vertical, simply glued to the side of the fuselage.The RC bottom hatch with a separate battery compartment.The wings, fuse & tail weighs 1.7 ounces so it should end up too much over 5 when complete. Quote Link to comment Share on other sites More sharing options...
Pat (rActive) Harbord Posted January 21, 2010 Share Posted January 21, 2010 I've been following the thread from the begining. What can I say? Fantastic to see skills and thinking like this. Absolutely beautiful. Can't wait to see it in full livery. Not sure I would ever fly it depron version looking good too and will be a great indication of what to expect of the masterpiece. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 21, 2010 Author Share Posted January 21, 2010 As the Depron Pup is all made out of the same material I rather expected it to end up more tail heavy than the balsa & tissue version. Piling up all the airframe pieces up on the fuselage in their correct relative positions I placed a small bar on my scale and then placed the fuselage on the bar at the likely CofG (lower wing leading edge). I then pressed down on the nose at were I guessed the centre of mass would act for the combined battery, motor, esc & radio.The result was not what I expected as it balanced level showing a total weight of 3.6oz or put another way it only needed 2oz to balance. The power train and radio weigh rather more than that so I looks like I shall have to move some of the bits back a bit. At the moment I cannot see an obvious flaw in this test. Quote Link to comment Share on other sites More sharing options...
Matt Halton Posted January 22, 2010 Share Posted January 22, 2010 I just found this build thread .Very nice build Simon, it looks amazing, I'm watching with keen interest. Cheers Matt Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 22, 2010 Share Posted January 22, 2010 Simon, That looks a smart little model, and surprising light. Being a balsa builder I have never given Depron a thought, but I must say I'm really tempted after seeing your efforts. If I was doing the test, once the test model was ballanced, I would ballast to equal the weight of the 'masterpiece'. Looking forward to the results. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 22, 2010 Author Share Posted January 22, 2010 All glued together ready for the flying wires. Nothing very sophisticated. The 1/16 balsa struts are glued into little slots cut into the Depron. The cabane struts and lower wings are simply glued to the side of the fuselage.The wing separation and stagger are correct. The top wing looks high because the fuselage is quite a bit shallower than scale.The motor will be mounted quite high on the firewall to keep the correct thrust line with no cowling. I estimate the drag will be roughly equivalent to scale diameter fuselage.It will have no U/C, at least to start with. Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 23, 2010 Share Posted January 23, 2010 Simon, It looks as I'm too late making this suggestion which was to fit a rudder to the test model. I suppose the addition could still be made by taping a 3g servo on top of the fuselage, the rudder doesn't have to be used but gives another optional control . My reason for making the suggestion is at take off or launch speeds I think a rudder will be essential, the rudder and elevator will be the only controls which will have any authority at extreme low speed . Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 23, 2010 Author Share Posted January 23, 2010 TerryI did think about it but I was keen to replicated the controls of balsa/tissue one. As you say it would be relatively easy to add rudder control to the Depron version if found to be essential. I am hoping it will fly at extreme slow speed all the time! A rather unusual pic. Tensioning the rigging. The complete wing bays and half the cabane rigging were all done with a single thread fed through pin holes in each strut and the ends tied to a tensioning weight (the pliers). Each strand was then carefully pulled to an equal tension and fixed with a touch of glue.Servo and control wires next. Edited By Simon Chaddock on 23/01/2010 12:36:13 Quote Link to comment Share on other sites More sharing options...
Sheldon Holy Posted January 23, 2010 Share Posted January 23, 2010 Brilliant! Yes, a 'test' plane, now THAT'S new" Quote Link to comment Share on other sites More sharing options...
Toni Reynaud Posted January 23, 2010 Share Posted January 23, 2010 Still following the thread. This bit makes me want to go out and get some real Depron instead of messing about with homecut blue foam! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 23, 2010 Author Share Posted January 23, 2010 The all Depron motor mount.Note the front of the fuselage has been cut back adjacent to the front cabane struts and the battery compartment relocated as tests suggested the CofG was going to be too far forward!It looks like it will end up weighing very little more than the balsa & tissue version. Edited By Simon Chaddock on 23/01/2010 22:59:58 Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 24, 2010 Share Posted January 24, 2010 Simon, Intresting little motor, what is the specification ? as I was thinking of going brushless in my Widgeon. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 24, 2010 Author Share Posted January 24, 2010 TerryIts a Blue Wonder 1500kv rated at 9A max, 7A continuous, just £5.42 from Giant Cod.A nice little motor (the magnets are particularly strong) that weighs 20gm bare but you have to accommodate its tube mounting. I glued a tight fit Depron tube over the mounting so I could then glue the Depron bracing directly to it. A very light installation although it probably wouldn't take the torque at the 18oz max thrust this motor is capable of! Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 24, 2010 Share Posted January 24, 2010 Thanks Simon, It has a similar spec to the BRC A2204 which I have in stock. 1400kv 9A max 19g 2s 400 mah prop 8x4 APC E thin Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 24, 2010 Author Share Posted January 24, 2010 Looking at the motor mount I realised it had some problems.1. With the motor wires at the top I was going to have some difficulty connecting them to the ESC.2. The motor mounting was rather flexible as the lower brace ended at the centre of the unsupported firewall.So engine mounting version 2 It now has the wires at the bottom so they will be accessible via the bottom hatch.The 3 braces are set in a triangle so the lower pair terminate at the corners of the firewall.I now have to wait for some more 3.7gm servos, the one size Giantcod are out of stock! At the moment every time I weigh all the bits, and make a realistic allowance for any missing, the total keeps coming out just a bit below 5oz! Quote Link to comment Share on other sites More sharing options...
John Bunting Posted January 25, 2010 Share Posted January 25, 2010 Hi Simon, and others,I just googled 'giantcod', for their website, to see the spec for your motor, and this came up:"Australian police launch enquiry after a man's head is found inside a giant cod at a fish processing plant". Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 25, 2010 Share Posted January 25, 2010 Simon, At that weight I should think you will have to treat the throttle very gently. BRC have 3.7g servos in stock @ £3.99. Edited By Terry Whiting on 25/01/2010 19:51:19 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 25, 2010 Author Share Posted January 25, 2010 Terry Thanks but I have just ordered 4 for £8 postage free, from Hong Kong of course. They may take a few days to arrive.I decided to use tiny "eyes" to guide the control cables. They are home made from fine copper wire with their ends pushed into the Depron and secured with a dab of glue. Simple and quick to fix. The 90 degree bend radius is rather sharp but the ease of actually threading it means the very fine 1.7lb line can be used. You can just about see it! Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted January 26, 2010 Share Posted January 26, 2010 Simon, How on earth they manage that price and free postage, which in itself must be near 20% of the cost, then still able to make a profit is mind boggling. It has be long term unsustainable. This has become a neat little project in it's own rite, it has certainly made me think of Depron in a different light as a building material for just such models. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted January 26, 2010 Author Share Posted January 26, 2010 TerryI suspect it is more to do with exchange rates than real costs. I could not agree more about Depron, particularly when it is used in built up structures where the strength of the Depron can take most, if not all the loads. This is born out by the fact that the Depron Pup will weigh little more than the balsa and tissue equivalent and it is a great deal more robust. I have a couple of 1500mAh 2s. Now I wonder if................ Quote Link to comment Share on other sites More sharing options...
Sheldon Holy Posted January 26, 2010 Share Posted January 26, 2010 I've just built another depron delta. Depron is brilliant stuff! I would have thought last sunday would have been good for this - no wind where we were. I had a good day Sunday, Allan was there with his Turbine Boomerang Elan... and he let me have a go! Sheldon Quote Link to comment Share on other sites More sharing options...
Terry Whiting Posted February 1, 2010 Share Posted February 1, 2010 No joy yet Simon?........ I'm beginning to suffer Blog withdraw symtoms Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted February 1, 2010 Author Share Posted February 1, 2010 Sorry Terry No post yet from HK so no servos or ESC.I have cabled up the ailerons as far as I can but can go no further. Its been sitting on the bench for nearly a week! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted February 2, 2010 Author Share Posted February 2, 2010 Yipee! Something to do. The ESC has arrived, 10A, very small and light.Shorten the leads a bit & add a suitable battery connector (now there's a fiddly job!) and test the motor. The prop, a 7x4, is to really too big (or pitch). 3.5 is the finest pitch 7" prop I can find so I may go down to a 6x3. I have ordered both!Now for the surprise. As above it weighs 120gm. Add 8 gm for the two servos so 128 or 4.55oz! Its actually lighter than the balsa & tissue one. Quote Link to comment Share on other sites More sharing options...
RonSpencerUK Posted February 4, 2010 Share Posted February 4, 2010 Simon Thank you for a fascinating and inspirational build log. I'm planning to build Mr Carr's 'Biff' from the February RCM&E but I'd really like to add ailerons; I'll have a go at your method and see how I get on. Will you be using the same system on the depron 'plane? If you are, some details will be fabbo. Quote Link to comment Share on other sites More sharing options...
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