Harry Twist Posted May 15, 2016 Share Posted May 15, 2016 Hi Phil, Your fuz is coming along really nicely. I'm not as far on as you but I have the main fuz made and nose /tail pulled in. Really enjoying the build so far. I am looking at making a fluted rudder - can I ask - going back to your 3 piece fluted rudder how did you work out the dimensions of the L -shaped cheek pieces? ( ie width top and bottom / step height location etc). I presume you measured from scale drawings of an A4? Any info appreciated. regards H Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted May 16, 2016 Author Share Posted May 16, 2016 Hi Harry, I did generate the general layout from a blown up scale 3-view drawing but made a few compromises to aid the build. The 2 ‘L’ shaped pieces were sized by drawing a line simply from mid chord at the tip and mid chord at the root of the original Fin 3 ‘rudder’ piece. I offset the base of the rudder by 35mm (measured along this angled line) to create the ‘L’ shape. As for the rudder ribs, they were all cut identical from strip of balsa 45mm long – long enough for the longest rib at the base. They are all 6mm wide at their L/E and 2mm wide at the T/E. They are then individually cut to size (cut the L/E away) such that all the ribs T/E remain 2mm wide. The ribs were glued onto a number of centrelines at a pitch of 15mm running up the rudder. These figures are slightly rounded to aid repeated measurement but will produce a rudder with accurate scale detailing by eye. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Harry Twist Posted May 16, 2016 Share Posted May 16, 2016 Hi Phil, Thanks for the detail - I can see how the L shape is sized now. Regards H Quote Link to comment Share on other sites More sharing options...
John A H Posted May 17, 2016 Share Posted May 17, 2016 With the sanding through the quadrant problem. As you had to reduce the width of the intake skins from that shown on the plan I wonder if that points to the problem been that the intake formers are two small. I've not posted anything yet as my fuselage is going together the same as everyone elses but I started mine at the weekend. Just up to building the intake and wondered about the intake skin been too large for the formers. Looking at the section views I was also worrying about the 1/2 inch quadrant not been enough wround that area. I might think about cutting slightly larger formers - are you able to measure the radius of the prototype maybe ? Quote Link to comment Share on other sites More sharing options...
John H. Rood Posted May 17, 2016 Share Posted May 17, 2016 Yesterday was the movie's 30th anniversary! So here's to your build of Jester's Go-Buggy! And thanks Phil for all you're doing to inspire us and guide us! You're doing a great job, but, as always, the REAL person we're watching is call-sign CHARLIE !!! And now, just a quick refresher... https://www.youtube.com/watch?v=WhYZc08Jk_Y Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted May 17, 2016 Author Share Posted May 17, 2016 Nice photos John (Rood) - Happy 30th Top Gun!!! Callsign 'Charlie' is looking mighty fine - I think she has the attention of the class there wouldn't you say!!? John (Hey) - I have been able to compare the intake formers from the laser woodpack blanks against my original drawings from which I hand cut the prototype parts and they are correct in size, within the diameter of the laser cutting anyway, certainly no 'measureable' error. However, that's NOT to say when I hand cut my prototype formers they weren't slightly on the large size (the outside of the line as opposed to the inside) - I think I do tend to do that. It was only 2 or 3mm on circumference I had to cut the skins down by - so on former radius that's a very small delta. I'm guessing my error is two-fold, I think my intake former slots on the fuselage sides are perhaps 1/32" too low on this production build compared to the prototype, that combined with the small tolerance shift between my 'plus metal' prototype formers, and the production laser cut kit which are towards bottom end tolerance is causing the problem I've encountered. I'm undecided still how best to suggest this is fixed, you could either; (i) Use the intake formers as they are but mount them 1/16" higher on the fuselage sides (ii) Remake the Intake formers very slightly bigger on radius thus pushing the skins outboard a little (iii) Leave the formers size and position as drawn, and simply add some additional triangular sanding stock into the internal corners ahead of former F4 - as Peter Garsden and I have done during our builds. All of these methods will eliminate the problem, but which should I instruct Traplet to modify the plan or laser pack for any future builders? Quote Link to comment Share on other sites More sharing options...
Lorenz Mueller Posted May 19, 2016 Share Posted May 19, 2016 Posted by Phil Cooke on 15/05/2016 21:36:57: I got some sanding time in the garden today and I've highlighted a slight error in the build, well, in my build anyway - this didn't occur on the prototype!? In shaping the fuselage around the deepest part of the intakes just ahead of F4 I've ended up with 2 small triangular holes where a little more material is needed on the inside to avoid a thin section. In this view one of the holes is clearly visible towards the top right hand corner. My recommendation would be to all - before sanding your fuselage to the final profile - please add these short sections of additional material into the top corners just ahead of F4 to mitigate any risk of thin walls or holing. I've sanded mine quite aggressively now, and have no holes. Holding it up against the light I can see the wood is a bit thin in those corners though, so I will add the triangular pieces just as a precaution. I don't think any other change than iii) (a small addition to the plan) is needed. Lorenz Edited By Lorenz Mueller on 19/05/2016 10:08:47 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted May 19, 2016 Share Posted May 19, 2016 I have worked out the problem guys. I had a hole on one side but not the other so why was that? The formers are all the right size I think. The point is that when I glued the two intakes, the rear of of one was too low and not in line with the tail outlet. This meant that the gap between the top of it and the top sheeting was greater than it should have been. The other side however had the rear of the intake higher up the fuselage and in line with the tail outlet, hence the gap between the top of the inlet and the top sheeting was less and thus less of the side sheeting exposed. Hope this makes sense. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted May 19, 2016 Author Share Posted May 19, 2016 So that's a function of how you cut the intake former recesses in your fuselage sides Pete? Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 5, 2016 Author Share Posted June 5, 2016 Been a little while since I've done any work on the A-4, but having returned from a relaxing family holiday yesterday I was keen to get back underway today - and it was another superb day for sanding with strong sunlight allowing every curve and radius to be visualised - and even a warm breeze to blow all my balsa dust off up the street! I taped up the snake outer at the rear to avoid me sanding it with my course paper...Use the plan sections as a guide to achieve the right shape, the fus is shown here fully rounded (or so I thought!) ready for final surface sanding. I say 'so I thought' as when I came to trial fit the vac formed canopy it was clear some further work was required around the nose and cockpit console section, the canopy wouldn't quite seat properly, proud at the front and in need of some further trimming at the rear. This is the first time I've fitted the canopy to the model, the prototype was built and flown with a solid balsa cockpit for speed of build. As per the full-size, I would expect to have to build a small, raised fillet at the front, but its clear the top of the nose section and console needs to be a little thinner here to allow the front canopy to sit fully. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted June 5, 2016 Share Posted June 5, 2016 Nice work Phil. I must start mine. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted June 5, 2016 Share Posted June 5, 2016 Nice work Phil. I must start mine. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 5, 2016 Author Share Posted June 5, 2016 errr, Yes! Only 14 weeks to go to the Fly-In!! With many other events to attend between now and then! Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 8, 2016 Author Share Posted June 8, 2016 A quick update before I put the modelling to one side to focus on prep for this weekends Fly-In. More shaping - the fin and tailplane have been sanded to profile, and the gaps at the front and the top of the air intakes have been filled with balsa and lightweight filler to achieve a perfect blend prior to glassing. Just a little more final shape refinement needed on the nose section and the fuselage is complete. Close up on fin and rudder - the rudder fluting side panels are sanded down to zero thickness at the T/E resulting in the 1/8" thickness required. Air intakes now complete, all gaps filled with balsa wedges, just need to add a fake splitter fairing at the front and we are done. Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted June 9, 2016 Share Posted June 9, 2016 What are you going to use for the fake splitter Phil? Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted June 9, 2016 Share Posted June 9, 2016 SPLITTER! Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 9, 2016 Author Share Posted June 9, 2016 hehehe "YOU Splitter!" Pete - nothing too fancy - was just going to shape a strip of 1/8" balsa and stick it to the fus wall forward of the air intake - its only a representation there will be no functionality and I'm not trying to stand the intake off from the fus wall... Quote Link to comment Share on other sites More sharing options...
KiwiKid Posted June 9, 2016 Share Posted June 9, 2016 Switches on .... ooops. Chocolate fish to the first person who knows what the hole in edge of the intake is for Quote Link to comment Share on other sites More sharing options...
John H. Rood Posted June 9, 2016 Share Posted June 9, 2016 Ashtray and no-fuss waste bin for the erks. And, if properly reinforced, a bottle-opener for all lagers and ales. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 9, 2016 Author Share Posted June 9, 2016 hehe nice one John! I must admit I've not seen this little feature before, I've been mulling this over at work... I thought about an easy access port to view the jet engines fan blades with a camera, but then that was ruled out as you can clearly get your head where you need it to do that (as per the guy in the previous photo!) I thought about speed probes or pressure instrumentation, but figured they would be better surface mounted on the inner intake skins? I then thought of a camera port - maybe for the gun? Is it a gun camera?? Its mounted just above the guns in the wing roots... And then I saw THIS... ...and noticed how the lateral position of the hole is in line with the air-refueling probe - is it a camera to aid lateral alignment to the tanker when you are in flight refuelling??? Please let me know if I've won the chocolate fish, otherwise I'll have to leave my desk and go buy a Snickers from the vending machine! Quote Link to comment Share on other sites More sharing options...
KiwiKid Posted June 9, 2016 Share Posted June 9, 2016 Very close - it encloses a small spot light to aid vision for night time refueling. Chocolate fish is in the mail. Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted June 9, 2016 Share Posted June 9, 2016 Not close enough. Deny the fish. Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted June 9, 2016 Author Share Posted June 9, 2016 Jees you're tough to please Andy... Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted June 9, 2016 Share Posted June 9, 2016 Speaking of refuelling probes - you haven't sent me the drawing for the printed part yet. Quote Link to comment Share on other sites More sharing options...
Mark Kettle 1 Posted June 9, 2016 Share Posted June 9, 2016 ...is it to catch any drips of fuel that don't make it to the tanks. Quote Link to comment Share on other sites More sharing options...
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