Phil Cooke Posted February 13, 2015 Author Share Posted February 13, 2015 I soaked a number of small sheets of 3/32" balsa in 'wicked strength' ammonia overnight to help with the extreme curvature - and with my eyes streaming in the fumes, I began to fit and trim the sheeting starting with the central underside piece first, then 2 panels either side... and then on the top side, this bit was a little simpler... With the wood still damp the panels are heavily pinned into position with no glue, they will be left like this until the ammonia dries which will take a number of hours. Then, with the pins removed the wood should stay in this exact form, meaning they can be glued in situ using pva - there should be no further 'working' required - they will just sit in position fully formed! I must admit I'm quite pleased with how they look - worth the effort getting the shape right here considering the scale detailed exhaust nozzles that will soon be fitted up against them. More curves than Kim Kardashian's backside! Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 14, 2015 Share Posted February 14, 2015 Hi Phil, looking good. You shouldn't need to soak the wood overnight, I brush it on liberally until my eyes can't take any more Then pin or tape down Fingers crossed Cheers Danny Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted February 14, 2015 Share Posted February 14, 2015 Curvey Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 15, 2015 Author Share Posted February 15, 2015 Having let the pinned out ammonia soaked panels dry for 24hrs+ they can now be removed and glued back into position. Before the pins were removed there was evidence of some shrinkage - I'm guessing the wood swells a little when soaked and it returns to its original form when dry, as opposed to it actually shrinking, anyway these gaps would need to be filled with 3/16" wedges, very simple to do to finish the job ready for sanding... Just to demonstrate, when the panels are unpinned from the fus they retain their shape perfectly. This means you can just sit them back on the fus and glue with pva - no 'forcing of material into position' is needed - no residual stresses in the assembly! Edited By Phil Cooke on 15/02/2015 11:08:46 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 15, 2015 Share Posted February 15, 2015 Wow that's a lot of shrinkage. I had the same problem with my Mustang. I found an article which said mix up the ammonia or vinegar 50/50 with hotwater then coat one side of the wood ie the outside then you can glue the other side. I agree though that you have pin it down but it is quicker as you do two jobs in one. Also coating one side helps the curvature Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 15, 2015 Author Share Posted February 15, 2015 The shrinkage gaps were easily filled with a slither of balsa, and once sanded up I'm quite happy with the result. I've sanded them as thin as I dare at the back as the taper angle in profile isn't quite right - but they will have to do. With any luck the 3D printed exhaust nozzles should arrive very soon, and I can't wait to drop them on the back of this former to see how they look! Whilst I had my sanding block out and with the opportunity to work outside this afternoon I spent some time sanding the first fuselage to shape going from a rough, planed finish to something more like the final shape. I had to take loads off the top of the fuselage 'shoulders' to enable to canopy to drop on - a little more is needed I think too. I stopped at the point I daren't take any more off without referring to some detailed photos for shape. I'm keen to leave the fus sharp edged and square where the intake splitters are to be stuck on - but immediately forward of that the angles and rads start to take hold. BTW - don't worry about my yellow canopy, this is an old one used for shaping purposes only, but new fuselages will each receive a brand new canopy! Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted February 15, 2015 Share Posted February 15, 2015 I quite like the tinted canopy! But how old is it to go yellow like that? Very impressive build Phil. No matter how fast I try to build I can't catch up. And I'm only doing one! Phil, did you have any issues with the fuselage shape close to F1? I have found that it seems to get too narrow too early and so it doesn't match the curvature I have on the nose cone. I have had to add some external doublers on the outside of the fuselage between F1 and F2 to get a bit more width. I'm thinking it really needs an F1.5 to hold the width better close to the front, but It might just be me! I did the rear fuselage underside today and I found one possible solution to the the problem you were describing with the fitting of the 1/2 inch slabs. I found that if just use a wider piece of 1/8 sheet at F6, you can sand a shape to fit the flat 1/2 inch slab. see below. I've used a sheet of 3mm depron (just easier to form!), but I'm sure it would work fine with balsa. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 15, 2015 Author Share Posted February 15, 2015 Hey Steve good to hear from you. I'm guessing my tinted canopy is 8 years old, its been in my workshop for ages... my Hawk canopy (similar age - but fitted on a model) is going the same way... Re: the shape of the fus - Is your concern with the bottom half of the fuselage only or can you see the curvature looking wrong in pure plan view? If its just the bottom half, then there's nothing wrong with your build - its meant to be like that. Ill try and find a picture that shows the fus at the particular angle where this is emphasised. But its to do with the transition from a fairly square bottom half fus to the fully circular radome. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 15, 2015 Author Share Posted February 15, 2015 Here you go - viewed from 3/4 rear its most noticeable - is this what you have tried to correct with your doublers? Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted February 15, 2015 Share Posted February 15, 2015 I had only been worrying about the plan view so far. When I look at my model in this 3/4 rear view I do see something like you show in that photo - so that must be good. But I've added the extra doublers in the mid height of the fuselage sides to try to get a smoother curve in te plan view. I'm working from an Airfix model as my guide. Interestingly when I look at that in the 3/4 rear view it doesn't show the same kink at the nose cone transition. So I guess it's not very accurate anyway. I'll do a bit a bit of measuring and a bit more sanding and see what happens - I'll probably end up sanding the extra doublers off altogether! Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 16, 2015 Share Posted February 16, 2015 Excellent chaps - very helpful all this discussion. I know exactly what you mean about worrying how much to take off and where. Obviously, with my blue foam shaping, I had to worry about that before I even started. I have 4 printed pictures all round my bench (Andy Meade idea and its a good one) which I keep referring to, as it is a complicated shape. I am glad I don't have to worry about bending balsa as there seems quite a lot of it. I took quite a lot off the top of the fuselage in order to make the canopy fit properly so that the sides curve up to meet, but not all the way along to the back of the canopy as this picture very helpfully shows. I made a mistake with the bottom curvature. I took it too far back, but I don't think it will matter too much. I am also planning to order the rear jet outlets, but am waiting until I have the exact dimensions of the rear outlets ie once the fibreglassing is finished. And I am learning words all the time - never heard of a radome before - comes of mixing with all you engineers Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 19, 2015 Author Share Posted February 19, 2015 Spent the last couple of sessions working on the canopy, fuselage spine and fin mount. I've deviated from the plan slightly in an attempt to bulk up certain features more akin to the full size. First the fin itself Ive cut from 3/8" instead of 1/4" - I think this looks much more solid when viewed head-on. Then the doublers at the base of the fin, to get the base of the fin scale on width these needed to be 1/4" thick each side, at their widest point. They do need to be tapered front and rear. These changes in turn change the arrangement very slightly of the spine, mine will be built up from 3/8" sheet again and sanded thinner down to 1/8" by the trailing edge of the fin. The curvy part of the spine immediately rear of the canopy I'm making from solid, carved balsa - I'll scoop out as much as I can to keep the weight to a minimum. The shapes I'm trying to achieve can be seen in this drawing which has some very useful fuselage cross sections. Sections G and H are of most interest for this post, but they will all prove handy when it comes to sanding the final shape of the fuselage. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 19, 2015 Author Share Posted February 19, 2015 A few photos to compliment the text in my last post... 'Curvy' section of spine just behind the cockpit is cut from solid and will be hollowed out once shaped - the remainder is tapered 3/8" balsa which is chamfered down to just 1/8" where it meets the fin on the inner wall towards the back... With the fin slotted in - the thicker fin doublers can be seen below - now 1/4" each side of the 3/8" fin - needs sanding to section front and back. My fin will be permanently mounted, I'll probably put a couple of short location dowels in the base of it to insert into the top of the fuselage but it will be amply supported by the spine too. Dry assembly of the basic parts - still requires some top sheeting infill and I need to carefully sand the spine in profile so it runs as a straight line from the base of the fin to the rear of the cockpit - at the moment the slight curvature on the top skins is bowing the spine which won't do. Beginning to look purposeful now though... Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted February 20, 2015 Share Posted February 20, 2015 Nice. Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted February 20, 2015 Share Posted February 20, 2015 Proper craftsmanship right there. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 20, 2015 Share Posted February 20, 2015 Very nice... Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 20, 2015 Share Posted February 20, 2015 Makes my rough finished fibreglass fuselage - not sanded yet look like a bag of ***** (can't fill this in for censorship reasons!) Looking very good to me - certainly would do for me Phil, but there you go. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 21, 2015 Author Share Posted February 21, 2015 I've received the 3-D printed jet nozzles now which you may recall Rez Manzoori had modelled in CAD from a couple of my close up photos of the full size jet. They look fantastic and will really finish the rear end off in style! The best news is that Rez has released the definition to Sean at RealModelPilots and with a test run now complete on their system you can now order your own set of nozzles from there! The nozzles have been defined with an internal flange which will be ideal for gluing them to the rear of the fuselage - they are very lightweight and once painted they will give a true scale finish to the business end of our Tornados. Many thanks to Rez again - not only for the skilled CAD work but also the free issue of his model to RMP making it available to the masses. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted February 21, 2015 Share Posted February 21, 2015 Excellent what a great finish. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 21, 2015 Share Posted February 21, 2015 I tried to order the nozzles from Real Model Pilots and was told that they weren't ready yet as they were still testing things? Look OK to me. No doubt they will tell you when they are ready. I have found some perfect plastic jets for the back. Will now do a post on my own blog Quote Link to comment Share on other sites More sharing options...
Fly_Boy_Rez Posted February 22, 2015 Share Posted February 22, 2015 The jet nozzles are ready to order folks. The testing was to ensure they printed OK on their printer. The initial model I supplied needed a little fettling, this has been done and the second print is a thing of beauty to behold. Top Marks to Sean at RMP for working with me on this. Rez Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 22, 2015 Author Share Posted February 22, 2015 I had planned to give both fuselages a good sanding to final shape today outdoors on the workbench but the foul weather here in Derbyshire put an end to that... Instead I shaped up the finbase which needed to be done before I can complete the spine, and that led to sanding the fin to finished profile and adding the characteristic ECM pods on the LE and TE. I sanded the fin to shape first, thinning the Trailing Edge to ~3/16" and rounding the Leading Edge - then cut out some pre-shaped pods. This way the sanding of the fin is much more accurate, and the pods protrude from a tapering fin section at a constant width just like on the real one. First one all finished. This is for the MRCA prototype hence the large scallop at the base of the fin, which was altered for the first production aircraft. I will cover the fin prior to gluing it to the fuselage as it will make that job very much easier too but before that it will be used as a dry fit to aid the spine completion. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 23, 2015 Author Share Posted February 23, 2015 Taken a little break this evening from the fuselage build as to be honest I'm running out of jobs I can do ahead of a good sanding which is needed before I can fit the spine and cockpit. I want to do that outdoors in good light so with work each day this week it will have to wait for the weekend (fingers crossed for no more rain and sleet like this Sunday!) So I've made a start on the wings tonight. Nothing too clever here, but just for the record... The panels are very nicely made by Barry at Foamwings.co.uk - white foam SD6060 section with 1.5 deg washout at the tip - shaped LE with epoxy bonded veneer skins and glass reinforcement let in below the veneer in to stiffen the Trailing Edges I've got two wings to make, one at 25 degrees sweep and one at 40 degrees sweep. I've made a start on the wing tips, following Andy's lead and building a balsa/ply/balsa sandwich which has proven so robust on the little Jet Provosts we built last season. Mine are laid out here ready to glue - 1/4" balsa base, 1/32" ply filling, 1/2" balsa top. I've marked up the wing panels for the ailerons using 3/16th sheet for wing T/E and aileron L/E - again, like Andy, I've tapered them slightly as this looks much more 'fast jet' like (it's not scale of course the real Tornado doesn't even employ ailerons!) Quote Link to comment Share on other sites More sharing options...
Steve Houghton Posted February 24, 2015 Share Posted February 24, 2015 Phil, Looking at all those complex shapes, I can see why you have decided to finish with tissue rather than film. It's a shame all that lovely woodwork needs to be hidden! Great work. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 24, 2015 Author Share Posted February 24, 2015 To be honest Steve I think I'm running out of time for the tissue and dope suggestion - if they are both going to be ready for 11th April (!) I think they are both going to be Solarfilmed for expedite! The one that needs spraying will get a coat of Prymol first to key the Solarfilm, this has been well proven in the past by Matt Jones on his Flanker. Quote Link to comment Share on other sites More sharing options...
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