Peter Garsden Posted February 5, 2015 Author Share Posted February 5, 2015 So how exactly will yours be built Andy - veneer covered foam? Or just foam like and RTF? Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted February 5, 2015 Share Posted February 5, 2015 Peter, Thanks for the info. However, I phrased one of my questions badly - I should have asked: How do you line up the fuselage hot wire templates (not the formers) on each side of the foam to be parallel before cutting? Is this an eyeball job, or is there a trick of the trade? I ask because I am contemplating starting on my Jack Edwards Zlin that uses foam covered in balsa for the fuselage and I've never cut foam before. I wondered if you experts start by cutting a 'flat' reference surface at the bottom and then lining up your side cutting templates against the reference surface? Alternatively, do you use rulers and squares to draw parallel lines right around the foam for your reference? Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 6, 2015 Author Share Posted February 6, 2015 Ah yes Steve I understand now. Obviously we do side and top and bottom templates. On them I draw either a middle line, or on the Tornado I used the datum line Andy drew on the plan. They ensure the side templates will be at the right angle and pitch. I then position the template so it is in the middle of the block, and mark a line on the foam at one end of the datum line. I measure the distance from the bottom of the foam - checking that the bottom is square of course. I draw a line where the front and back of the side template rest. I take away the template and yes, use a set square/ruler to mark it right round the block. That ensures that the side templates are in line with each other at the same distance from the front of the block. I go to the other side of the block for the other template - we already have lines right round the block for the front and back markers. I then measure again lines at the correct distance from the bottom of the block to line up the datum marks for the horizontal plane. I then pin into position the templates lining them up with the datum markers, and the front and back lines both sides. I then double check that they look in line in both planes. The same principle applies to the top and bottom templates save that I used centre lines which are also marked on the plan. I actually positioned top and bottom before side. You also have to cut the top template, then tape it together to keep the block square, before cutting the side templates. You then peel away the scrap and you get your shape. That is a square form which I then sand to shape as you have seen above. We marked lines every inch to ensure we cut at the right speed every inch from 1 to 35, then we were cutting we called out the numbers. Same way as you do wings. So yes you have the right idea. It is the same method which one uses for wings where you line them up laterally with the middle of the root profile, the same distance from the bottom of the block both ends. It you are not melting the foam afterwards, I have to say that blue foam is quite heavy - we used it for wings and it was OK, but white foam is much lighter. The problem is that you can sand blue foam quite easily, but not white foam really. Have I now answered your question? Incidentally, if you want to build a transformer I have an article I wrote for LMMGA on how I did it and the parts I sourced for it. I also have an article on how I built my Alpha Jet. Edited By Peter Garsden on 06/02/2015 18:26:35 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 9, 2015 Author Share Posted February 9, 2015 Forgot to say Steve that although you can't sand polystyrene foam, you can sand other types of white foam such as EPP, I think, though I have never worked with EPP or other types of white foam. Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted February 9, 2015 Share Posted February 9, 2015 Hi Peter, Huge thanks for your copious reply. Yes, that's all quite clear now. I had such a busy weekend that I didn't manage to read your reply before I started cutting, but I have done essentially what you explained. You make several references to 'we', so I presume you have a helper to move the bow smoothly. This is the main area where I had teething troubles, trying to do it alone so far, with rather shaky results. I have now started a thread on my build of the Zlin, so I shall post my problems over there, to save cluttering your thread. I shall take a look at your transformer build, but I've started off with 12V battery power. Thanks again. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 9, 2015 Author Share Posted February 9, 2015 OK a bit of progress tonight. I have covered the jets - or are they intakes - just don't really know as I am not an aeronautical engineer - jets to me, forgive me for my ignorance. Anyway, have covered them with brown parcel tape. Yes I know there are wrinkles but it doesn't matter because it is an inside mould. I used an iron to make it stick better and smooth it down. One can use solarfilm, but why waste expensive film which we are going to throw away, when the mould is dissolved. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 9, 2015 Author Share Posted February 9, 2015 Also have done the fin and tailplane. They are rough and ready yet as I have not sanded them. They need quite a lot taken off so I am going to use my Proton sander to save lactic acid in my arms Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 9, 2015 Author Share Posted February 9, 2015 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 9, 2015 Author Share Posted February 9, 2015 I also made the pivots for the tailplane out of square brass and wheel collets. This looks cockeyed but it isn't. It is the paper that is not flat. The powerfull soldering iron helped a lot. I had to be careful not to get solder on the rod inside or the grub screw. Seems OK and tight. Also had to make sure the square edge lined up with the flat side of the tube. The collets I bought are bigger than the plan, but I don't think it matters, save for a little extra weight. Not sure if it is nose or tail heavy. I suspect the latter, hence my fibreglass outlet jets may have to be replaced with the suggeste plastic bottles? Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted February 9, 2015 Share Posted February 9, 2015 Moved on a bit more Peter Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 9, 2015 Share Posted February 9, 2015 Looking good Pete! I'm sat here rubbing the sawdust out of my eyes having just done a nights planning and sanding on my Tonkas. Coming together nicely - I'm still contemplating using the wheel collets for the tails or whether just to glue them on - I suppose they will be less susceptible to damage in transport if they are removable. Definitely INTAKES by the way Look forward to seeing your fibreglass fuselage take shape! Quote Link to comment Share on other sites More sharing options...
John Mccullagh Posted February 10, 2015 Share Posted February 10, 2015 Great looking fuz Peter cant wait to see the finished article ,i was curious about the balsa nose till i saw your pictures ,i built a pss viggen some time ago the same lost foam method ,but with a seperate nose moulded in f/g and screwed on so i could replace it if needed.john Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 10, 2015 Author Share Posted February 10, 2015 Building has been delayed a little as I managed on Sunday to fly my Willow F3F into the side of the slope at about 50mph at Bosley Cloud as it went below eye view. I heard a crack and then had to go and retrieve it. It was in a bit of a mess but not as bad as I feared. The wing was delaminated and the fuselage broken at the front. I had to leave half the nose cone in the hill side so need a new one. It is on order. Nearly done now with a bit of blue foam and lots of epoxy. Just got to paint it back to health. Also I have covered the other air intake and some of the fuselage with brown parcel tape. Will be able to put a layer of fibreglass on soon. I have however spotted a potential weak point to the rear of the wing. Will need a bit of head scratching. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 Sorted out what I will do with the weak point at the rear of the intakes. It will need a sharp edge but should be OK. Today is firbreglass day - two layers of 160grams cloth and 1 layer of 80 grams. Resin all warmed up. Have cut out all the cloth for all 3 layers using the same templates I used for the fuselage. Worked well. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 I have done a bit of tips reading. One tool recommended for the resin is a Jenny Brush, so I bought a pack for about £3 from the Works. Cheaper than brushes which you can only use once really. I do have some glue brushes but they really are too small for this size of application. I am sure you use a Sharpie, They are invaluable Also they said, buty a really good pair of scissors (Fiskar - abut £20) for cutting the cloth, and don't use them for anything else, so I have marked them. The cloth, however, does fray. Next step is to use spray 3M77 glue to attach the cloth to the mould. I have a handy spit like support so you can spin the fuselage round to apply the cloth then leave it to dry - next picture. Edited By Peter Garsden on 14/02/2015 14:52:49 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 Well, the first layer of cloth is on and drying. The cloth stuck well to the waxed parcel tape. It helped a lot. I used the Jenny brushes to dab the resin all over, and wet it out. Hasn't stuck in some areas but we can sand vigorously later. This shows the cloth glued down to the fuselage. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 Then some picture showing the wetted out cloth, and the spit like cradle I use for holding the fuselage, whilst I work on it. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 This is the 3M spray and the excellent resin I get from Easy Composite. I really should have got laminating resin rather than this one, but the hardener at 1:2 is easier to calculate. I have a set of digital scales which are excellent Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 14, 2015 Share Posted February 14, 2015 Some great progress this weekend Pete - you will very quickly leap ahead of all the other builds with this now I think - how much internal support work is there needed do you think once you've got the outer glass shell sorted?? Keep up the good work, we are watching with interest!! PS - don't get any of that nasty resin on your Tx Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 I am still going to insert formers F1, F2, F4, F6 - very important and might make it in ply. If I have to remove the jet outlets at the back to get access to the all moving tailplane, then I might glue in F8. I have some very useful full size drawn the edge of the fuselage drawings of formers from Andy. Also I have put in some carbon 1 inch tape either side of the nose and by the wing trailing edge for extra strength. Don't worry - the trannie is well oujt of the way. More likely to get it on my pants, but haven't so far as have been wearing my apron. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted February 14, 2015 Share Posted February 14, 2015 Looks great Pete, well done. I've got to try this method soon! Quote Link to comment Share on other sites More sharing options...
Monz Posted February 14, 2015 Share Posted February 14, 2015 Is the tape just to prevent the polyester resin eating the foam? Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 14, 2015 Author Share Posted February 14, 2015 The tape is there for several reasons:- Yes to stop the resin eating the foam, though I use epoxy not polyester which dries too quickly. I don't know if it would dissolve to be honest. To give a smooth inner surface for the fibreglass so as to make it easier to glue formers to it. To give the resin a solid smooth surface to purchase against. I think it would soak into foam, and be heavier when finished. To make it easier to pull out the last of the dissolved foam after you have poured acetone into the middle at the end. Quote Link to comment Share on other sites More sharing options...
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