Mark Kettle 1 Posted September 6, 2014 Share Posted September 6, 2014 Steve I just like to say it's been 177 hrs and 17 mins since your last entry, has there been any progress ? .....Not that I'm counting. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 7, 2014 Author Share Posted September 7, 2014 Sorry Mark, I had to take the family away for a week of sunshine, so no progress at all. Will get back to the build later today when I've mowed the lawn, and all that stuff! What is this Gnat and Vulcan video that you mention? Where do I find it? Peter, That's a much more impressive cutting set-up than mine. I had an old 12V transformer from a garden light set, rated at 3.5 Amps, so I couldn't make a very long bow. I chose 26 inches to go with the 26SWG wire I bought, to give the 'right' cutting temperature. So I'll have to stick to small models, or make the wings in sections. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 7, 2014 Share Posted September 7, 2014 Only joking progress - did you have a good time? The Gnat's and Vulcan, It's good Steve Enjoy **LINK**. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 7, 2014 Author Share Posted September 7, 2014 I had glued the leading and trailing edges to the wing panels before I went off on holiday. Today I razor-planed and sanded them to shape, and I discovered two interesting things. 1. The slight under-camber seems to have disappeared now the panels are completely dry. 2. The root rib template shape provided on the plan is not the right shape! Based on my earlier comments on the plan accuracy, I should have known better than to use the shape drawn on the plan!. If you ever make this model, I would suggest you copy the root rib shape from the main wing section drawn on the fuselage side view instead. The template shape has too much curvature on the underside of the leading edge. You can see the problem in the photo below. I will have to add a strip of 1/16th sheet, for about 3/4 inch behind the leading edge, and do a bit more sanding. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 8, 2014 Share Posted September 8, 2014 Like you say Steve I'm sure that extra piece of 1/16th will sort it. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 8, 2014 Author Share Posted September 8, 2014 Today I've glued the wing tips in position, and tack bonded the trailing edges/ailerons in position, so that |I can shape everything in one go. I've also added those extra strips of 1/16th balsa but they're not in the photo. Then, I drilled the holes and cut the slots in the fuselage sides for the all-moving tailplane mechanism, before joining the the 2 fuselage sides together. The plan suggests a mechanism based on a commercial bellcrank (which as far I can tell is no longer available), and some 10 gauge wire running in plywood bearings. I reckoned this was all going to be a bit flexible and loose. So, Having done the JP build and been very impressed by the aileron torque rod design which Andy Blackburn designed into that, I thought I could make a mechanism based on the same components which should be much more rigid and positive. So the bellcrank is cut from a sheet of fibreglass, with some local reinforcing doublers epoxied on. The axle and the rear joiner bar are made the same way as Andy's torque rods - 3mm carbon fibre rods epoxied into 5/32" aluminium tubes. And the axle will run in bearing made from a blue snake outer. I'll then epoxy some ply reinforcings onto the fuselage sides where the bearing tube comes through. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 8, 2014 Share Posted September 8, 2014 Steve the bellcrank is nicely made, were do you buy sheets of fibreglass from, I've never used it before. Edited By Mark Kettle 1 on 08/09/2014 22:10:31 Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted September 8, 2014 Share Posted September 8, 2014 Nice progress Steve, looking good! Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 9, 2014 Author Share Posted September 9, 2014 'where do you buy sheets of fibreglass from' - like most things these days, the easiest place to get them is Ebay. They seem to be intended for making model car chasis, but they're useful for so many more things. They're available in several different thicknesses too. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 9, 2014 Share Posted September 9, 2014 Thanks Steve. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted September 10, 2014 Share Posted September 10, 2014 Maplin sell Fibreglass sheet (A4) sized but only 1/16" thick IIRC Martyn Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted September 10, 2014 Share Posted September 10, 2014 What used to be the distributor MacGregor are now called hobbyplastic and they sell epoxy glass and tufnol sheet in various thicknesses and sizes. I think they sell on ebay too but their website is www.hobbyplastic.co.uk Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 10, 2014 Author Share Posted September 10, 2014 These are the wings sanded to shape. and I pulled in the front and rear of the fuselage, and glued some retaining pieces in place. Next I want to put the aileron linkages in place, before joining the two wings together. Quote Link to comment Share on other sites More sharing options...
Chuck Plains Posted September 10, 2014 Share Posted September 10, 2014 As you mentioned yourself Steve, these super little jets have a special place in the memories of a certain generation. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted September 14, 2014 Share Posted September 14, 2014 Evening Steve - hope that PSS Gnat progress is going well - I went to Duxford yesterday and got to enjoy this pair performing their routine in superb conditions - a photo to provide a bit of encouragement!! Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 15, 2014 Author Share Posted September 15, 2014 Lovely photo Phil, and 2 nice paint schemes to think about. I like that one above too, posted by Chuck. I haven't seen that one before - presumably a Red Arrows special edition? It looks a bit complicated to do in solarfilm though. No progress on the build this last weekend - had to take my daughter off to university. But got my aileron linkages and hinges done tonight. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 16, 2014 Share Posted September 16, 2014 Steve are you thinking of the Airfix box illustration in sliver orange/red finish. The wing section on the model is very similar to the full size as in picture LINK here: **LINK** Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 17, 2014 Author Share Posted September 17, 2014 Mark, Yes, when I set out on this build, that was my intended scheme. It's still top of my list, but now I'm starting to wonder what colour the orange/red actually is. In the few photos I've found, it doesn't look like the dayglo orange which several PSSA members have used on the JP, but it doesn't look like a true red either. So I'm not sure whether I can a find a solarfilm (or similar) which will be right. So I'm starting to think a red arrows scheme might be the best option. ( I don't want to have to do all that heavy tissue, dope and paint stuff, what with my wings being smaller than the plan,etc!). Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 17, 2014 Share Posted September 17, 2014 Steve I bet the colour on the 'Airfix' box is accurate with them selling paints etc. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 17, 2014 Author Share Posted September 17, 2014 Yes I had the same thought . So I've just ordered a pot of of humbrol 209 Fire Orange on ebay. I'll then see if I can match it to any any available film coverings. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 20, 2014 Author Share Posted September 20, 2014 I put the 1/4 inch bottom sheet on the fuselage today (after first applying a few strips of glass cloth and epoxy resin to reinforce the triangular sections near the nose where I had to make saw cuts to help with bending the fuselage sides. I joined the wings together last night, again reinforcing the joint with a strip of glass cloth and epoxy resin. Today I've dug a couple of holes in the wing for the servos, and glued on some lite ply 'picture frames' for mounting. I've also fitted one of the 2 anhedral braces recommended on the plan, and trimmed the front section off the wing where it fits into the fuselage. Fitting the anhedral braces is quite tricky, and I'm not convinced that they will have any significant strengthening effect on the wing. The wing seems perfectly strong enough with a fibreglass skin joint and a PVA foam core joint to me. So I think I might leave out the rear brace. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 21, 2014 Author Share Posted September 21, 2014 Today I stock the nose block onto the fuselage. It's just a few pieces of hard 1/2 inch balsa ( and one 1/4 inch) with alternating grain direction. but I spent most of my time on making templates for, and cutting, the blue foam 'side cheeks' for the fuselage. it took me a while to decide on the shapes. I didn't use the section profiles shown on the plan because they looked too semicircular compared the airfix model (my reference), and as usual, the dimensions were inconsistent in each view. There's a bit of sanding to do on the rear end of the rear section to get it o blend in to the jet pipe a bit better, but it's the best I could do. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 22, 2014 Share Posted September 22, 2014 Engine / intake sides look good Steve what surface finish are you putting on then? Progress at this rate should see it finished on time I mention this after reading your doubts on Peters Hawk build / thread. Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted September 22, 2014 Author Share Posted September 22, 2014 I glued the side fairings or 'cheeks' onto the fuselage last night. and then tonight I cut away the recesses for the wing,so I was able to put the 2 together for the first time. It's starting to look a bit like a Gnat! If you're wondering why the side fairings don't reach all the way to the jet pipe, it's because I thought I would do the last little bit in balsa so that I can open it out with a fairly thin edge (like we did on the jet provost). The pot of Humbrol 209 arrived today, and it confirms that I should go for the dayglo orange solarfilm. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted September 22, 2014 Share Posted September 22, 2014 It's looking the 'bee's knees' Steve. Quote Link to comment Share on other sites More sharing options...
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