Biggles' Elder Brother - Moderator Posted January 23, 2014 Author Share Posted January 23, 2014 Ah - yes good point Danny. On my Tucano build last year I used pieces of card as spacers to protect against exactly that problem,... But we get away with that here because the rear former slopes backwards significantly - more than in the Tuc. Also of course I was intending to cover the Tuc fuselage with lightweight glass cloth so had to allow for that as well! Here of course - no fuselage covering! Clever boy Lyndsay - he thinks of everything - well,...nearly everything! BEB Edited By Biggles' Elder Brother - Moderator on 23/01/2014 23:06:01 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 23, 2014 Share Posted January 23, 2014 LOL should have guessed you would have it covered Still its worth pointing out for the less experienced. The first cowl I did for my YT Hurricane wouldn't come off at all. Had to break it off. Felt right sill y I did Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted January 24, 2014 Share Posted January 24, 2014 I thought the same when I was building my own one Danny, but in the end it wasn't a problem. Probably because of my lack of precision The gap looks big in this photo - but it is less than 0.5mm - you have really to slightly push the wing int it's seat - and it doesn't fall out if you turn the plane upside down without the bolt. maybe because of the light (used the flash for the picture) VA Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 24, 2014 Author Share Posted January 24, 2014 Hi VA, I notice that you've sheeted the top of the cockpit in a number of separate pieces. I was thinking of trying to do it in one piece - did you try this? It doesn't look easy - and may not even be possible - that's why I thought I'd ask before I try! BEB Quote Link to comment Share on other sites More sharing options...
AJ Posted January 24, 2014 Share Posted January 24, 2014 Hi Beb, I did mine as a single sheet then cut the cockpit out after it was fitted. I just soaked the sheet for a while in some warm water. Andrew Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted January 24, 2014 Share Posted January 24, 2014 Yes look like a prime candidate for sheeting in one piece especially if you are going to stain the wood I did a similar curve on a Fokker Dr1, except I chickened out and did it in two by the looks of it Cheers Danny Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 25, 2014 Author Share Posted January 25, 2014 Well I tried it one in one piece using some card - no thank you - the double curve is too much for me! So in the end it got done in two pieces,... While that is drying I decided to make up the undercarriage. Lyndsay gives no full size drawing for the U/C just a sketch - but no big deal its all pretty standard. We make this from piano wire - I had some 8AWG in stock (that's about 10SWG) so decided to use that. Now you can bend this with lots of grunting and groaning in vice with a combination of hand bending and a hammer - but it damn hard work. About 5 years ago I bought myself a wire bender - and I would not be without it now. This is the beast,... The block bit goes in the vice, you feed the wire between the rollers and the forming pin and away you go. The important trick in bending undercarriages up is to allow a bit more wire than you think you will need and start bending from the middle outwards - for some reason it seems to be easier to get a basically symmetrical undercarriage that way. So, here's the mains tried for size against the model,... Always leave the "axles" overlength - you can go back and trim them later. Talking of trimming you'll need to cut this stuff. Well a hacksaw will not "hack it" (Oh dear!) piano wire is far too hard - you'll be sawing away for ever. The easiest way is with a cutting disk in a mini-drill like this,... Its very difficult to build model aeroplanes without a mini-drill - if you don't have one, get one! Most other tools you can work around not having - but for somethings only a mini-drill will do. You don't have to buy a Dremmel - though they are very good - you can get cheap ones that are also good. But get one if you intend to take up more of this building lark! And while you're at it buy a couple of pairs of these,... DO NOT USE A CUTTING DISC IN A MINI DRILL WITHOUT SAFETY GLASSES!!! Sorry about the capitals - but it really is important. This cut will create a lot of sparks. And anyone who's done this will tell you - these discs can shatter! You only have one pair of eyes and you wont be much use as a builder or a flyer without them! Get the glasses and wear them! So next we make up the trailing arm bit - more cutting and bending - you'll get all this U/C out of one 1m length of piano wire - easily. I then tweak that with pliers, fit it in place. Once we're happy, burnish up the piano wire on both the mains and the trailing arm - I use a fibreglass pencil for this - but a small wire brush or some emery would work just as well. You want the wire nice a shiney. Once its clean like this try to avoid touching it if you can. Next we wrap the joints in wire - I use heavy gauge fuse wire,... Next we solder this. Now the keys to sucessful soldering are; cleaniness and heat. That's why we burnished up the piano wire. Here's what I'm going to use to solder this,... Standard leaded solder, a liquid acid flux and temperature controlled iron set quite high. I do have a gas torch and to be honest I'd usually do this with that because its easier and quicker. But I wanted to show that it can be done with a fairly modest iron if that is all you have. Apply the flux, run right in the gap, apply the iron, the flux will "shhhhccc" and boil off, that's fine its what we want. Then apply the solder - to the job not the iron! You will know if all is good - the solder will stay bright and shiney and will flash over the joint - running happily between the wrapping wires and the piano wire. Dont skim the solder make sure its right through and around the joint,... Finally clip off any excess wrapping wire and if you have used an acid flux like me run the whole thing under the tap for a minute or two to wash out any remnants of the acid - or the wire will eventually corrode! You should be left with an undercarriage with bright shiney respectable looking joints. BEB Edited By Biggles' Elder Brother - Moderator on 25/01/2014 17:44:59 Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted January 25, 2014 Share Posted January 25, 2014 Nice work as usual Dave and well done for being brave enough to bore people with the H&S lecture, to my mind this sort of stuff can't be said enough, when it comes to cutting piano wire I use a set of Draper mini bolt croppers as well as the dremel the nice thing about the croppers is the safety angle as well as the speed Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted January 25, 2014 Share Posted January 25, 2014 nicely done sir. Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted January 25, 2014 Share Posted January 25, 2014 BEB, coming back to the cockpit sheeting - well I didn't even try to do it in one piece.... I leave these kind of specialities to people like Danny By the way - the guy sits lonely in his cockpit now and has nothing to look at. Any idea about old style instruments which could be printed out and glued into the cockpit? VA Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 26, 2014 Author Share Posted January 26, 2014 I think even Danny would struggle with this one VA! - the double curvature was going to make it very difficult indeed. Although Andrew managed it, so full marks to him - it defeated me! Re furnishing the cockpit - well they didn't have much in those days - so I shall go "minimalist" - very minimalist OK, having sorted out the main undercarriage yesterday it's time for the tail skid. I really liked the way VA did this - so I have unashamedly copied his method! We bend up a bit of thinner piano wire - 2mm this can be done with a vice and pair of pliers! Then very carefully make a rebate in the triangular mounting piece,... This arrangement has the great advantages that the skid is on the centre line and it requires no brackets so it's possibly a little bit lighter. Any potential weight saving at the back end is not to be sniffed at in my opinion. Next we fill the rebate with epoxy and smear epoxy onto the surface of the balsa mounting plate and surrounding structure then glue a 1mm outer ply plate in place,... I used 5min epoxy here - but only mix enough to do one side at a time, it goes off very fast and you will not have time to adjust and fettle both sides. Once this side is set then you can mix some more epoxy and do the other side. With all that done I added a little black heat-shrink to the wire skid - just to give it a certain 'je nais se quoi' as PeteB might say . Next up we have to engineer the idler bar on the rudder control system. The reason why the model needs this is that the fuselage is quite narrow and can only accommodate a fairly small arm on the rudder servo. By having this idler bar we effectively multiply the movement of the servo so getting a bigger rudder throw. More rudder may be handy - especially on take off and landing I suspect - because of the relatively narrow undercarriage causing a bit of directional instability on the ground and of course we have no steering from the tail skid to help us. Let me introduce what, to some of you, might be a new material,... This is grp sheet. I bought 3 sheets of this quite a while ago on ebay - you'll find it listed as "RC Car Chassis Plate" and at the time it was about £2 a sheet. Its 2mm thick and is basically a glass reinforced composite. Its quite light and both very stiff and very strong. It has loads of possible uses - I'm on my second sheet out of the three and you can see I've already had a little nibble out of this one! Its particularly good for control horns, servo-arms and the like. It cuts easily, with a hacksaw, and files/sands well. Another great advantage is that its semi transparent - or at least translucent. This means you can trace parts from plans onto it and once installed on you model it's quite discrete. I decided to make my idler bar from this,.. And here it is in a little "mock up" I did just to test that the assembly was going to be fine - just on a scrap bit of balsa,... And here it is side on showing the assembly,... Basically its a M3 bolt of appropriate length passed through the wood with a washer under it to protect the wood. Then on the other side there is an old collet which is purely there as a spacer to lift the idler arm higher. Above the collet is a washer then an M3 nut. This nut is tightened and that holds the M3 bolt in place as a post to mount the idler bar on. There is then a washer, the idler bar itself, another washer and finally the nut that holds the idler bar on. Note that in the final installation this last nut will be a Nyloc - but I've used a conventional nut here just to test everything, Nyloc's don't work so well if you take them off then put them on a again repeatedly. So, that's all working well and is ready to be installed. Next I shall make control horns for the rudder and elevator from the grp then start installing the control system. BEB PS The women folk went shopping yesterday and had instructions to purchase 3 yards of black hat elastic - which, god bless 'em, they duly did. so we have the supply of the "rigging wires" sorted! Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted January 27, 2014 Share Posted January 27, 2014 Nice one. I like the FRP arm you made. I was lazy and went for a servo arm I had in the bits box... Well - no problem with that - except that it is bright blue VA Quote Link to comment Share on other sites More sharing options...
AJ Posted January 28, 2014 Share Posted January 28, 2014 I just had another look at my DF cockpit sheeting. Looks like I didn't do it in one piece as I thought. In fact I split it lengthwise so I did each half with a single piece. My idler bar I made from 2mm ply. I fitted mine exactly the same as BEB has shown his above. As the ply is likely to wear I sleeved all the holes with brass tube. So far it has worked very well. Andrew Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 29, 2014 Author Share Posted January 29, 2014 Ladies and gentlemen, if you have tears prepare to shed them now! For disaster has struck my Dawn Flyer! Pleased with how things were going, and blissfully unaware of what cruel barbs fate had in store for me, I decided to stain the fuselage of the DF before fitting the control runs and radio gear - thinking it would be easier with nothing installed. I carefully selected the "Antique Pine" stain - tastefully rich, but not too dark. Carefully rubbed the fuselage down in preparation - smoother than baby's posterior. Lovingly wiped it down with acetone to get all the dust off the model. Turned the heater on - just enough to take the chill off - not so much as to really warm the room up. Stirred the stain diligently. Took a brand new brush, and carefully started to apply my stain. At first all seemed to be going well - then I got down to near the cockpit end of the rear sheeting - and an ugly pale spot appeared! "What the hell is that?!" I thought. Realisation dawned on me,...is a glue mark. You see I've never stained a whole fuselage before - the odd cabane strut yes - but not a whole fuselage. And I've never made as much used of CA on a model a I have on this. I was realising that there is a fundamental incompatibility here. If you get CA anywhere on the model - then no matter how carefully you wipe it away and then rub down the area - the fact is its gone deep into the grain and you can't get it out! Result, that bit of wood is now "waterproof" and so its "stainproof" as well! So we get a pale spot. Carefully looking over the model it was with some alarm that I started noticing pale spots and lines around all the joints!!! The fuselage looks dreadful! Like a photograph of a dalmatian dog in negative! I'm too ashamed to even show you a picture at the moment - I'm desperately trying remedies - but with not 100% success. I've made some of it look better - marginally. But the main spot I noticed first is proving resistive to being put under wraps. I will continue my efforts but it's possible I may end up with a very accurate model of the "Shuttleworth Collection Dawn Flyer" - complete with heavy original patina! Photo tomorrow maybe - if I can bring myself to put them up! Are we downhearted - to right we are! Are we defeated? Never! These little challenges are what modelling is all about - keep saying it, keep saying it,.... So the motto for those about to build - remember this one isn't being covered - if it was there would be no problem. If you plan to stain the fuselage then absolutely no glue outside of the joint faces! Where's the whiskey bottle,...... BEB Quote Link to comment Share on other sites More sharing options...
Lindsay Todd Posted January 29, 2014 Share Posted January 29, 2014 Use a clear varnish and seal the entire surface, then go back when dry and apply the stain, you might need to use a coloured varnish and whilst still wet use a stiff bristled brush and stroke the surface along the path of the grain to simulate the wood grain, several layers later you can achieve quite a good finish. I am not a fan of cyno for all sorts of reasons I guess this is another. Linds Quote Link to comment Share on other sites More sharing options...
Plummet Posted January 29, 2014 Share Posted January 29, 2014 Try Vodka. Put a tiny amount on a cotton wood bud and rub it on the pale area. Then observe that it had no good effect. Mix vodka with tomato juice, Worcester Sauce, and a bit of Tabasco. Drink Repaet. Pullmet Quote Link to comment Share on other sites More sharing options...
John Fontana Posted January 29, 2014 Share Posted January 29, 2014 Well in that case, BEB, I am well and truly stuffed also. Quote Link to comment Share on other sites More sharing options...
Robin Kearney Posted January 29, 2014 Share Posted January 29, 2014 Sorry to hear that BEB, very down heartening to discover something like that when you have spent so long creating something! I made the same mistake on the deck of a boat last year, good luck with remedying the situation, sounds like you have made some progress. Quote Link to comment Share on other sites More sharing options...
Phil Winks Posted January 29, 2014 Share Posted January 29, 2014 OOOOH NASTY and not easy to remedy mate you have my sympathies, I can't think why I didn't see that coming, having used CA as much as I have, though to be fair this wood worker forgot it wasn't being covered, I must try and pay more attention in future. it will be interesting to see your solution though, my way would be to use progressively darker stains till it covered Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted January 29, 2014 Share Posted January 29, 2014 Lindsay said the right thing. I covered mine with HMG Sanding Sealer - after that a light use of 400 abrasive paper - job done. Of course, the stain will not work as nice as it would with untreated wood - but it looks the same everywhere. And the sanding filler helps to improve the surface of the balsa - it is less attracted by hangar rush OK- what to do: paint it with an acrylic paint, chose a nice brown of your choice, and nobody will notice - ahem - those reading the forum may well see it .... VA Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted January 29, 2014 Author Share Posted January 29, 2014 OK, we have a suggested plan - a fairly drastic one - but the only one I have real confidence in working so far! I can live with the lattice work as long as I get the big "flat" surfaces right. So I'm planning to rub these surfaces down to create a decent key and then glue 1/32" balsa sheet to the fuselage sides and the rear top decking. I'm even thinking of using a waterproof spray adhesive to do this - no liquid glue! That should give me a fresh, glue free, wooden surface to re-stain. Thoughts? BEB Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 29, 2014 Share Posted January 29, 2014 sounds like a plan to me, contact adhesive? how thick is obechi? Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted January 29, 2014 Share Posted January 29, 2014 That's what I'd do BEB, 1/32" balsa with a contact adhesive, very lightly sanded to avoid going through it! Quote Link to comment Share on other sites More sharing options...
Kevin Fairgrieve Posted January 30, 2014 Share Posted January 30, 2014 Ohhh that`s bad news. I just glued my first two bits together using Aliphatic. I do not intend to use any CA, so will I have the same problem? Kev Quote Link to comment Share on other sites More sharing options...
Vecchio Austriaco Posted January 30, 2014 Share Posted January 30, 2014 Kevin: I suppose so - aliphatic stains remain sticky and will not take the paint in the same way as the untreated wood. BEB: Now I start to believe that your Dawnflyer will do snap rolls - you do all this actions only to reinforce the structure All the best with the repair VA Quote Link to comment Share on other sites More sharing options...
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