Martin Whybrow Posted February 12, 2015 Share Posted February 12, 2015 Martyn, I've had success bending small diameter tube by filling it with cerrobend prior to bending; cerrobend is a low melting point alloy (~70C) which can be melted in a cup stood in boiling water; to fill the tube I attach a length of fuel tubing and a syringe, dip the tube into the molten cerrobend then draw the plunger of the syringe out to suck the cerrobend into the tube. Once it's bent, drop the tube in boiling water to melt out the cerrobend. I got my cerrobend on ebay for about £15 for a kilo; I've been told that it's now been replaced by cerrosafe which doesn't contain the toxic metals that are in cerrobend - it doesn't bother me as I don't plan on ingesting any, and it's never heated hot enough to produce significant amounts of vapour. Edited By Martin Whybrow on 12/02/2015 12:50:52 Edited By Martin Whybrow on 12/02/2015 12:51:08 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 12, 2015 Share Posted February 12, 2015 Well I don't count as a maestro but I have an opinion If you have the desire to make some mods to it why not. I can't settle with the flap/ailerons so i'm going to redo those. John Quote Link to comment Share on other sites More sharing options...
Martyn K Posted February 12, 2015 Author Share Posted February 12, 2015 Thanks all I do sometimes think that I may be flogging the proverbial with this. It is my first scale build and as I said in my intro, I want this to be a learning exercise. To me that means learning new skills, problem solving and fabricating using different materials and techniques. There is a lot of that in this model. I would also rather (and expect to) make mistakes on this model and learn from them rather than make expensive mistakes on another model which is more costly and matters more (if that makes sense). A larger scale Chippie - its a possibility but I need to find out if my immune system will fight off the Detailitis bug that Danny has passed to us Danny - I have mailed the image to you.. it's also here: Martin W. Thanks for the idea - sounds like that is just like what I need. I'll investigate M Edited By Martyn K on 12/02/2015 14:14:15 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted March 30, 2015 Author Share Posted March 30, 2015 A bit more on this now that the Concept has been completed. I have been working on the sprung tailwheel assembly. I decided to try and manufacture one out of brass tube, silver solder and patience. A sequence of photos - hopefully mainly self explanatory.. I. Brass tubes filed and jigged Leave everything as long as possible before cutting - use water to cool it (after the solder has hardened) and this will restore the hardness in the tube It looks rough - that is the silver solder flux that is cleaned off with a wire brush Front pivot from brass sheet with a 10BA bolt for the hinge. There is no real load carried here - the load is carried in the rear tube which bears against the 3mm base plate. The plate is 3mm lite ply The frame that carries the spring is 3mm birch ply. A second length of tube sits in the first and soft soldered into place. A M3 washer sits over the junction between the 2 tubes and is the bottom pressure point for the spring - which works in compression. The fork is cut from duralumin, the wheel is 20mm diameter, stolen from my AcroWot with the hub filed flat. A 10BA bolt is the axle. I think that the wheel is 2mm too small in diameter. The main shaft is M2.5 threaded rod. The nut above the fork has the flats filed off so that it is rounded Total weight at this point was 14.9gms The gap was filled with epoxy and micro balloons and filed down and then painted with hi build primer, white primer then white paint. The fork is painted with aluminium paint. Almost ready for fitting, I have also wound some Kevlar thread around the spring box to make sure it keeps together when it gets the shock loads. I have cut the rear tailplane seats from 1/2" balsa glued into position and test fitted the tailplane which appears to be horizontal You can also see the fitting of the tail wheel yoke assembly, I am quite pleased with that From the top, the elevator push rod goes through the spring box - and it doesn't bind.. Rudder and Elevator servos have been hidden just in front of the cockpit area This means I can get my cockpit floor at almost the right height Here is a test fit of the flooring.. Nice corrugated effect - I am not sure if the spacing is correct but it looks OK and suitably rough. Finally tonight, I got the snake outers fitted (sort of) - a bit more work yet to get the linkages done.. More to come but probably not for another couple of weeks, I am away from Thursday for a few days but may get a little more done tomorrow. Linkages need sorting next then cover the elevator, tailplane, fin and rudder before fitting. Martyn Edited By Martyn K on 30/03/2015 22:44:24 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted March 30, 2015 Share Posted March 30, 2015 Great workmanship Martyn, way beyond anything that I feel up to, getting the thing to steer without everything fouling stretched my limits! The back end in this plane is very light, I can't see the spring being asked to do a lot of work, you probably need something pretty soft. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted March 30, 2015 Author Share Posted March 30, 2015 There is only 3mm of travel Colin and I have actually wound and fitted another spring which is less stiff. TBH, as I said in my OP, I want to use this build as an exercise in learning how to make replica parts, there is no rush, this will take at least another year I think. I am really enjoying these fiddly bits - makes a big change from traditional airframe building M Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted March 30, 2015 Share Posted March 30, 2015 I see where you're coming from Martyn. I need to get mine done quicker than that because I want to complete other projects and time is still a problem. I like doing things like that though. I made up a tank from brass sheet and soldered it together last year. It works and doesn't leak either, so there could be hope for me yet. Quote Link to comment Share on other sites More sharing options...
John Timmis Posted March 31, 2015 Share Posted March 31, 2015 Nice bit of detailing there Martyn. I like it. Quote Link to comment Share on other sites More sharing options...
Nigel Day Posted March 31, 2015 Share Posted March 31, 2015 Great work Martin. The infection is well-developed. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted March 31, 2015 Author Share Posted March 31, 2015 I have been diagnosed with CDO. Its a bit like OCD except the letters are in the right order Martyn Quote Link to comment Share on other sites More sharing options...
Nev Posted March 31, 2015 Share Posted March 31, 2015 Nice job on the tail wheel Martyn. Can't fault the workmanship. Do you think there is enough meat left on the fork, wouldn't like to think the axel was going to snap out. Looks really good though. Nev. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted March 31, 2015 Author Share Posted March 31, 2015 Thanks Nev i hope it will be strong enough. I used duralumin rather than aluminium as it is much harder and it is also quite thick, I filed the edge to a curve to try and simulate the tube on the original. It seems quite tough. If it breaks I can replace it as it is screwed onto the shaft - clamped between two nuts. Martyn Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted March 31, 2015 Share Posted March 31, 2015 Looks o.k to me Martyn, the fiddly bits do my head in John Quote Link to comment Share on other sites More sharing options...
Martyn K Posted May 18, 2015 Author Share Posted May 18, 2015 A little bit of progress this weekend Still working on the back end.. I have now got my linkages in place and I have soldered a tiller arm onto the top of my steerable tailwheel The rudder linkage comprises of a terminal screw which is clamped to the clevis rod. This has a brass pin protruding downwards which goes through the hole in the brass plate and is secured by a soldered on brass washer. A bit of light ply as a cross brace to support it while assembly is in progress It was apparent that I would soon need to add some rivets.. So following Danny's excellent blog, guide and encouragement Rather than use a glue bottle, I used a cheap disposable syringe. My thought was that I can pressurise this (a little glue - lots of air) then this should give me a nice consistent flow rate. For a first attempt, I was quite pleased. The rivets just sit proud - although the last 2 were not proud enough.. Then following "el maestros" instructions, covered the rudder in Solartex. To my uneducated eye, it looks OK... I have never ever seen a live or dead Chippie, so I am relying on others photo evidence Then last night spent an evening fettling and trying to see what I need to do to get the tailplane and fin to fit. I also started carving the fuselage tail piece which I think that will get binned - not happy with it at all. and Fiddly - isn't it? Note - I have also glassed the tailplane - it looks OK. More to come - eventually. Next job is tail end tapes and stitching.. Martyn Edited By Martyn K on 18/05/2015 14:52:18 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted May 18, 2015 Share Posted May 18, 2015 Looking good Martyn, what glue did you use for the rivets? Cheers Danny El Maestro indeed LOL Quote Link to comment Share on other sites More sharing options...
Martyn K Posted May 18, 2015 Author Share Posted May 18, 2015 Hi Danny (Maestro) Evo-Stik Resin W (Green bottle). My standard building stuff. I left it dry for a good 2 hours possible longer- the rivets actually went totally clear as the glue hardened. Not sure if that is good or bad I need to decide what to do about the missing bumps. Reluctant to strip the covering back as I don't want to damage the other but may have to redo this bit Martyn Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted May 18, 2015 Share Posted May 18, 2015 Hi Martyn, that Evo-Stik is my "rivet" glue of choice too these days. It dries a little harder than the RC modellers glue. It is a bit thicker/viscous to use however and I had to go up a needle size. The rivets going clear is normal I don't leave them as long as you though, as soon as they are clear they are done As for your missing bumps, I wouldn't worry, they should be so subtle that a few flattened ones wont matter. I did find the covering iron had to be kept clear of the "rivets" or they would squash flat Cheers Danny Quote Link to comment Share on other sites More sharing options...
Martyn K Posted May 18, 2015 Author Share Posted May 18, 2015 Thanks Danny I was in no rush yesterday so happy to let it harden. Quite an entertaining experience - ended up wiping most off until I got the flow rate right. Martyn Quote Link to comment Share on other sites More sharing options...
Martyn K Posted January 6, 2017 Author Share Posted January 6, 2017 There must be something in the air. I have restarted my Chippe as well. I have to admit that I was a bit disillusioned with the design. To build a scale model from a proven designer's plan, I expected the basics (like the sizes of the flying and control surfaces) etc to be correct as drawn. When I started this I was quite prepared to do quite lot a rework to make everything fit. After a while, my enthusiasm waned and demands of fleet maintenance and an especially horrendous year of airframe replacement following a number of crashes took precedence. I also don't have the affection for a Chippie that many of the Chip Shop builders have. I would rather have built a biplane - I prefer WW1 or an accurate replica of a 60's or 70's aerobat So, the Chippie went up in the loft and was promptly forgotten about. However, the guilt factor at the back of my mind didn't go away and the fact that I needed a scale model for events like Ashbourne were still there as well. A couple of off-line chats with Danny and I think I have a way forward that will hopefully keep me happy. Basically, I am now going to build this as (hopefully) a good stand-off scale model. It wont be a contest model and it will definitely not be to Danny's standard. I can only dream about building to that standard. My plan is to complete the airframe and then add sensible amounts of detail - rib tapes and rivets and things like that - until I lose my patience or get bored. Not sure about panels although they are likely as well. I am not going to make any corrections to the plan - ailerons and flaps will be built as drawn and irritatingly massively incorrect and angled ribs will remain straight. I'll skip things like sliding canopies, stitching etc. although I hope to have a reasonable level of detail in the cockpit. Basically, something nice to look at but without the wow factor. I am also going to use electric as the motive power so I don't have to worry about fool proofer. Basically I am going to use a KISS philosophy So, to restart and re-motivate myself, I have ripped out the radio gear in the Fus (I don't have to worry about a scale level floor now) and started work on the wing. All ribs present and correct. I am laminating the LE from 2 pieces of 1/8 sheet to make a false LE, then cap the sheeted LE with the second 1/8 sheet. First half went together OK. Just in time, I spotted that the holes for the aileron pushrods were missing. So did the second half. The port wing is being assembled upside down in case you haven't spotted that. The 3 root ribs each side to be fitted after the doublers are in place. It took me 3 attempts to get this correct - my errors mainly. Eventually used a laser alignment with a straight edge as belt and braces. Some strange forces occur in my shed that attract me there and I am pretty sure that they bend light as well. More to come but only while I am waiting for the glue to dry on the Hornet Moth Martyn Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 6, 2017 Share Posted January 6, 2017 Great to see you back at it Martyn the wing is definitely a challenge.... I look forward to eventually flying all the Chippys together somewhere Cheers Danny Quote Link to comment Share on other sites More sharing options...
Andy Muckley Posted January 6, 2017 Share Posted January 6, 2017 Hi All. I t would be a great event to fly ,or even maiden them all together somewhere, sometime, like The Master said.(sorry danny) it's like eating an Elephant , one bite at a time. Maybe we need a date/ venue to aim for regardless of quality of finish. what you guys think ? Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted January 6, 2017 Share Posted January 6, 2017 It would be a nice idea to get them all together, although better if they've already been maidened and sorted before getting there! I share some of Martyn's views of the design, also as I've mentioned before of the marginal (brittle) quality of the wing ribs, I shoiuld probably have sent them back rather than persevere. I found that working inside the wing sorting out aileron linkages etc, that it split very easily and I had to do quite a bit of repair work as I went along. I don't think that I will be going overboard on the scale detail, stand-off will do and if the plane survives, I could add detail later if I feel the need. The first thing to do is finish and fly it. Quote Link to comment Share on other sites More sharing options...
John Timmis Posted January 7, 2017 Share Posted January 7, 2017 Martyn Glad to see you back on the job again. I think that we are almost neighbours. Perhaps we should meet to compare Chippie experiences. Danny A mass fly in of Chippies would be great idea. Looking forward to it already. John Quote Link to comment Share on other sites More sharing options...
Martyn K Posted January 9, 2017 Author Share Posted January 9, 2017 Hi all A bit of progress while waiting for the glue to dry on the Hornet Moth The missing wing ribs have been added and I have also added the upper wing sheeting. I used lots of clamps to get nice tight joints. I have also increased the size of the undercarriage blocks. Only because it is what I had available. As I have a bit of spare material, I may make slightly different undercarriage brackets than those shown on the plan. Nothing too radical though. The LE sheeting went on quite well. I always feel much happier with the wing ribs secured - it makes the wing much more manageable. A couple more changes. I am going to use 2 aileron servos - but mounted centrally and 2 flap servos activating the flaps using a torque rod. I'll probably use side mount low profile servos for these and the R/E. Certainly feeling happier now the build has restarted. Off work with Flu so not getting much done - except re-reading Danny's 'Poor Mans Spitty' blog - again. I need to decide whether I am going to use the HK U/C legs or settle for simple 8G piano wire jobbies. Jury is still out on that. Martyn Edited By Martyn K on 09/01/2017 15:15:47 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted January 9, 2017 Author Share Posted January 9, 2017 Posted by John Timmis on 07/01/2017 16:21:52: Martyn Glad to see you back on the job again. I think that we are almost neighbours. Perhaps we should meet to compare Chippie experiences. Danny A mass fly in of Chippies would be great idea. Looking forward to it already. John Hi John Yes - it would be good to meet up. Whereabouts are you? Martyn Quote Link to comment Share on other sites More sharing options...
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