Colin Leighfield Posted November 4, 2016 Author Share Posted November 4, 2016 Hi Chris, thank you, yes, I know about that one. It wasn't a success, but it's certainly intriguing. I've never seen it modelled, but I'm sure it could be done. I didn't know there was a plan. Using a contra-prop and eliminating torque reaction and spiral slip-stream would probably help with marginal stability issues. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 5, 2016 Author Share Posted November 5, 2016 Here I am following the plan detail, finishing the centre section trailing edge with t/e stock, drilling for the wing bolts and fitting the 1/16 ply supporting plate underneath. Although time consuming, I decided to hollow out the t/e stock for the ailerons and in filling with 3mm Depron. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 5, 2016 Share Posted November 5, 2016 I wonder how much weight that willsave on the ailerons. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 5, 2016 Author Share Posted November 5, 2016 About 1/3 Peter. Having said that, it's only about 16gms overall and hardly worth bothering about. However, the t/e stock I had was quite hard and dense, waving it about there was a lot of inertia. It feels much less unwieldy now. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 5, 2016 Share Posted November 5, 2016 Well that is half an ounce, significant amount Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 5, 2016 Author Share Posted November 5, 2016 I know you don't mean it! I'm not that impressed either! Still, it all adds up, or down, depending on how you look at it! Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 5, 2016 Share Posted November 5, 2016 No, actually I do mean it. In the past I have turned sheet parts into Swiss cheese for no noticeable saving so I was really surprised at how much it did save. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 6, 2016 Author Share Posted November 6, 2016 I think that a balanced combination of Depron and wood can give useful weight savings and reduce building cost with a finished airframe that is robust and practical as a weekend flyer. Depron is also quicker to cut and work than balsa, so speeds up the build. The extra time in this project has been working out the retracts and fiddling about with detail like in filling the ailerons! However, adding up the actual building time in the shed it's pretty quick, the problem is the time gaps in between when nothing gets done. However I'm getting close now to the final stages of Permagritting (very quick on Depron)! And sanding to shape ready for finishing. It will start to look something like fairly soon. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 6, 2016 Author Share Posted November 6, 2016 Wing top skins going on. There are a lot of glue lines on both surfaces to line up for the contact adhesive to work, but with a bit of care you get it done. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 6, 2016 Share Posted November 6, 2016 Looks very nice Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted November 6, 2016 Share Posted November 6, 2016 wonderful work Colin. I like Depron as it is so easy to work with. this one will be a very nice flyer. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 6, 2016 Author Share Posted November 6, 2016 Thanks Peter and Tony. I really want to get this one done. Although I've modified the structure, it's still Peter's design and I've wanted to do one of his for some time. Also it's a bit more butch than a Ballerina!(Says he ducking and rapidly leaving the room)! Only joking! Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 7, 2016 Share Posted November 7, 2016 No, they aretwo different aircraft. Ballerina is more of a lady ,Super Marauder is a bit of a thug. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 7, 2016 Author Share Posted November 7, 2016 Peter, by the time I've finished with it, it will be a lot of a thug! It's in my mind's eye. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 7, 2016 Author Share Posted November 7, 2016 Wing skinning complete now, real progress! Starting to look at wing-tips, wing bolt mounting plate etc. I thought I would look at weights so far. The wing with ailerons but without tips, with retracts, wheels and aileron servo is 509 gms, about 18 ozs? Raw fuselage with co-axial motors, propellers, wiring and two escs, rudder and elevator servos is 468 gms. 16 ozs? Tailplane, rudder and elevator, completely un-sanded, 57 gms. 2 ozs? All up 1034 gms, 36 ozs, 2 lbs.4ozs. Some weight will come off with the extensive sanding to be done and a bit added with cockpit, Ezekote and 17gm. Glass-cloth plus paint. On top of that will be the flight battery. However, Peter reported 5lbs. 4 ozs, 84 ozs, giving a wing loading of 21 ozs/square ft. I'm 36 ozs, 3 lbs. inside that so I reckon the weight saving will be considerable and 375W should fly it fine Edited By Colin Leighfield on 07/11/2016 19:42:13 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 7, 2016 Share Posted November 7, 2016 That sounds interesting. I wonder how the actual power compares. Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted November 7, 2016 Share Posted November 7, 2016 Looking good Colin. Depron can make some super weight savings in a model. makes the cost of motors and batteries a lot cheaper. Tony B Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 7, 2016 Author Share Posted November 7, 2016 I don't know Peter, but the smaller 221W contra-prop set-up flies the XB42 very well, 53" span but not much over 2lbs. in weight, that's a mostly Depron build. I fly that with low-efficiency GWS three blade props, simply because I think they look good. I will use decent two bladers on this. It is looking promising, but if there are any power deficiency issues it won't be a big job to convert to a conventional brushless motor. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 7, 2016 Author Share Posted November 7, 2016 Hi Tony, that's true. I've put the wood in where I think it makes a difference and bearing that in mind, this is working out even lighter than I thought it would. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 12, 2016 Author Share Posted November 12, 2016 Because the hard runways at Fradley are very abrasive to wing tips, I decided to put in some small skids made of 3mm lite-ply and 16g wire. It occures to me also that if ever there's a retract problem and I have to land with both or one wheel up, they'll be very useful. They are epoxied into the outer ribs W12, but I've glued 1/16" balsa capping ribs onto them to distribute any load. I've built the tips using 6mm grey Depron with 1/16" balsa laminated on and used 6mm grey again as gussets. To finish them I've used the 3mm white aero Depron, which has curved around very nicely. I'm now onto shaping the fuselage ready for finishing. Edited By Colin Leighfield on 12/11/2016 17:56:04 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 12, 2016 Share Posted November 12, 2016 One used tvo be able to buy nylon tip skids. I think they wer American. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 12, 2016 Author Share Posted November 12, 2016 I think I've seen those Peter, though not for a while. Hopefully these will be ok. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 13, 2016 Author Share Posted November 13, 2016 The wing is finished, bar final sanding/Ezekote/covering.I'm pleased with a weight of 540 gms including retracts. I will need to make covers for the undercarriage legs though. Not quite as good as Simon's apparent 2x240 for his Ballerina, but I'm happy with what has turned out to be a light, strong and stiff wing. I'm working on the other bits now. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted November 13, 2016 Share Posted November 13, 2016 Vefy nice and light Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted November 13, 2016 Author Share Posted November 13, 2016 Thanks Peter. Absolute lightness isn't the most important thing for me on this one, I've tried to build in strength as well. So far, so good. Quote Link to comment Share on other sites More sharing options...
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