john stones 1 - Moderator Posted December 15, 2014 Share Posted December 15, 2014 Making progress Colin, all looks nice and straight John Quote Link to comment Share on other sites More sharing options...
Terry Walters Posted December 15, 2014 Share Posted December 15, 2014 Sorry chaps but the weather was rotten over the weekend and still is! Fog/mist/cold etc. Even then I didn't get much done except run some IC engines on my B+D Workmate engine mount and re-intall an OSFS26 into my poor old abused Phoenix Rainbow - yet to try it in situ. It had been playing up. This pm spent all afternoon fettling the flaps/ailerons fitting and alignment on the Chippie wing. Have cut out and replaced one of my R1s more accurately so as to get the port inboard hinge in the right place. The starboard one needed a bit of inspired sculpting on the outboard edge of R1. Now they look OK and maybe tomorrow I'll do something permanent with them and then get the servo mounts in. The IP is waiting - I can feel it calling me. When the weather inproves I want to do the fus planking sanding outside if I can. If not it'll be mask time again! Bit slower than I would like but really enthusiastic still. Have got my 'rivet kit' now - bottles and hypos. Had to get the needles from UK as due to the strong protectionist regime here in France I would have to buy them at a Pharmacy (if they were prepared to sell them to me) at a vastly inflated price! You know you cannot buy anything in a Supermarket, not even pain killers. You have to have a conversation with a pharmacist to get anything and then they will spell out the dose (written on the packet anyway) and make you feel like a child - the real reason is to protect their Retail Price Maintenance. Over here nothing is geared for the consumer only the need to maintain profit and protect their franchise. Call me a cynic? Terry Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 15, 2014 Author Share Posted December 15, 2014 We're still jealous anyway. Quote Link to comment Share on other sites More sharing options...
Terry Walters Posted December 15, 2014 Share Posted December 15, 2014 LOL - Colin - You'll be fine next year - you'll be so busy you won't know how you managed having a job to do too as well! Terry Quote Link to comment Share on other sites More sharing options...
Terry Walters Posted December 15, 2014 Share Posted December 15, 2014 Mine will be 4 servows too Colin/John . Hitec Mighty Minis on the flaps and thin wing servos for the ailerons. Terry Edited By Terry Walters on 15/12/2014 20:36:24 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 16, 2014 Author Share Posted December 16, 2014 Done a bit more on the starboard aileron. The servos I ordered from Giant Shark at the end of last week arrived today, including 4 Corona thin wing servos, they look ideal and have 4kgs pull. 2 for the flaps and 2 for the ailerons. They will fit in very easily. Quote Link to comment Share on other sites More sharing options...
AlexJ Posted December 16, 2014 Share Posted December 16, 2014 Hi Colin, I will have to sort out servo mounts for my wing soon, I hope you don't mind me cribbing your ideas? Your chippy is coming along very well. Alex Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted December 16, 2014 Share Posted December 16, 2014 Looking down the l/e of those flap/aileron It looks like a good un Colin John Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 17, 2014 Author Share Posted December 17, 2014 No problem Alex. Thanks John. Looks ok so far. These are so light that I've not used Depron here, might as well use the wood bits. When I've got the other one done I'll work out the servo positions and mountings. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 22, 2014 Author Share Posted December 22, 2014 Frustratingly slow, but managed to do a bit more today on the ailerons and flaps. Started to build the port side, the starboard one looks quite promising. These will be covered with doped on Esaki silk as on the rudder, which showed no need to use tissue first. Edited By Colin Leighfield on 22/12/2014 20:43:18 Quote Link to comment Share on other sites More sharing options...
Nev Posted December 22, 2014 Share Posted December 22, 2014 Yes I found these a bit tedious as well Colin but satisfying when thay are done. Nev. Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted December 23, 2014 Share Posted December 23, 2014 Nearly done with them Colin by the look of it. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 Thanks Nev and Nigel. Should get a bit further today. I thought I'd show this photo again. It shows the rudder built on a Depron core but using the balsa rudder post from the wood set, with Depron tip, Depron ribs and 1/32" balsa cap strips, 2 coats of Ezekote, then Esaki silk with just two coats of dope. No sign of any attack on the Depron and the silk is tight, free of pores and smooth, ready for painting. This sets the scene for the elevators and the wings, we'll see how it goes. Quote Link to comment Share on other sites More sharing options...
Terry Walters Posted December 23, 2014 Share Posted December 23, 2014 Hi Colin - that all looks very interesting - I will be waiting to see what the overall weight difference will be. Are you looking more to the building advantages of Depron or weight saving, or both? Anyway have a great Xmas and stay away from that nasty work thing for a while! All the best to you and yours, Terry Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted December 23, 2014 Share Posted December 23, 2014 Hmm. Using foam rubber for the elevator tips is a novel idea Colin. Should help with the weight saving but I'm not sure about its aerodynamic abilities. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 It's not foam rubber Nigel, it's Depron. Pretty much as stiff as balsa and when coated, very tough. Try it, you'll be surprised at how easy to work it is and I've already proved from experience that when covered with Ezekote and light glass cloth, it's probably better than balsa. Certainly no worse. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 I've just realised that the earlier picture showed the elevators before the grey Depron tips were sanded and coated. Here they have been. The wing tips on the Barnstormer are done exactly like this and I can assure you from experience that they are tough enough and probably more resilient than balsa when finished. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 Terry, weight saving wasn't a key objective, although there will be some. If you look at the way Danny has lightened his elevators by cutting large holes in the balsa though, you won't improve much on that. It's just that I've found the Depron dead easy to use as well as being lighter and cheaper than balsa. The primary structure though is exactly as the plan, so I just want to see how it comes out. I think it's going to be absolutely ok. I'm at home for two weeks, then doing three days in the office before we head off to HK, Oz and NZ for 3 1/2 weeks, so building will come to a halt then I'm afraid. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted December 23, 2014 Share Posted December 23, 2014 I wish i could find a very interesting article I once read. It showed the strength values of identical test open structures covered in the various covering mediums, tissue, silk, nylon, solarfilm, solartex etc. All the wood used came from the same stripped sheet etc. It showed that the iron on films added virtually nothing to the overal strength of a structure. Silk, nylon and tissue came out top, in that order, actually adding IMMENSE strength to the structure. The only thing I would add to what Colin has said about the differences between wood and depron, is that with wood you can select the grain/weight to match the job in question. Really light contest grade wood is lighter than depron, is it strong enough, well yes in my opinion it is. However in the soft to medium range I would say depron and balsa are probably close in strength when used as sheeting, but when the grain is used correctly in balsa it has advantages over depron for spars, imo. I think the best would be balsa depron laminate as Colin has already suggested. I really look forward to seeing how much lighter this comes out Colin Cheers and merry Xmas Danny Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 23, 2014 Share Posted December 23, 2014 Colin Is your Depron skin thicker than the balsa it replaces? If so would it not increase the thickness/chord ratio of the surface slightly unless you have 'thinned down' the underlying structure to compensate. I was always felt the skin thickness of Depron, whilst a beneficial in many ways, had a significant effect on the bending strength of very thin wing structures. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 It slowly dawned on me that I fell hook, line and sinker for Nigel's wind-up. I'm getting worse! Danny, I've read the same article and it has stuck with me. It's the reason why I suggested to Nigel that if he wants to re-set his wing incidence in any way, to consider doing it using a doped on material because the heat shrink options won't do that very well. They're not strong enough and don't give the same degree of flex resistance, besides being subject to variations in tension with ambient temperature. Also I think your summing up of the relevant characteristics of balsa and Depron is spot on. Simon demonstrates very well how the simple addition of a thin strip of balsa top and bottom of a Depron spar gives it a lot of compressive strength. I've certainly found that to be true of the Depron Barnstormer, which has had a couple of harsh arrivals without the wing showing the slightest sign of distress, to my great surprise! I don't suggest this is a case of one being better than the other, I'm just exploring what is possible and still safe. Simon, the Depron I'm using for skinning is the 2mm aero quality, replacing the 1/16" (1.5mm) shown on the plan. The extra 1mm on the wing thickness doesn't trouble me at all, I'll live with that! As far as the effect on strength is concerned, it seems to me that the key requirement for this leading edge sheeting application is compressive strength. I'm satisfied that particularly when coated with Ezekote and glass-cloth, this is more than adequate. Bear in mind also that the primary structure in this case remains exactly as on the plan, it is only the sheeting and cap strips that have been substituted by Depron. I could get egg on my face, but am reasonably confident that it will be ok. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted December 23, 2014 Share Posted December 23, 2014 I don't see it being much other than a different material myself Colin, maybe we all ought to make use of it a bit more ? my only defence is I like working with balsa and i'm stubborn John Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 I'm the same to be honest John, but I thought it might be interesting to explore what options there might be. It does seem to have some interesting possibilities though. Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted December 23, 2014 Share Posted December 23, 2014 Sorry Colin. I guess you must be busier/more wound up with the time of year. Still, it generated some useful discussion didn't it? Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted December 23, 2014 Author Share Posted December 23, 2014 I got too focused Nigel! You're right though, all of this discussion is healthy and prompts new ideas. I only got interested in messing with Depron because of some other interesting threads. Before I wouldn't have given it house-room, just thinking about it used to put my teeth on edge! Perhaps some of the discussion about your wing will be helpful for you, it shouldn't be a big problem. Quote Link to comment Share on other sites More sharing options...
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