Andy Sephton 1 Posted October 16, 2018 Author Share Posted October 16, 2018 I've been trying to figure out how the fuselage formers go together and kept coming up with a blank, so the next step was to try a dry fit. To do that I needed the 1/8" cross-grained plate that fits along the upper edge of the basic fuselage. Accordingly, two were made over the plan and a set of A3 photocopies of the relevant bits. The width is not critical, so I've cut the parts oversize. I'll fit them by sanding to conform with the existing formers after they have been fitted. The ruler is to ensure that the edge to be fitted on the model is flat: Next job was a dry fit...when I discovered that the 1/8" plate is stepped behind former F4. It's clear on the plan when you look for it, but it took me the dry fit to discover it: Also, looking at the upper formers, although the insides of formers F5 and F6 is cut too wide, the outside edge is just about right: Next job with be to dis-assemble the dry fit and put it back together with some adhesive..... Watch this space for more updates. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 16, 2018 Share Posted October 16, 2018 Looking at those pics then Andy, you just removed wood from the inside of the side formers? Excellent info, thanks for sharing Cheers Danny Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 16, 2018 Author Share Posted October 16, 2018 All the formers are as per plan Danny - I've not modified any of them yet. However, I have made the 1/8" plate a bit oversize, so it may cover up any errors in the side formers. I'll have a better idea once I've glued to all together. Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 27, 2018 Author Share Posted October 27, 2018 I've been plodding along slowly with the fuselage and lower wing since the last post. The next few posts should bring the build up to date. The lower side plate has been added to the front of the left fuselage and side formers added at the rear. The latter were helped in place with dry-fitted stringers. The slots appear to line up quite nicely, but the formers are a little over-long. They should stop level with the top of the bottom longeron. They'll be trimmed once dry. I've since added the side formers and side plates to the right side of the fuselage, but there are no pictures as yet. I'm delaying adding the side plate around the wing mount until the wing centre section has been constructed to give me a pattern - thanks to Danny for that advice! Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 27, 2018 Author Share Posted October 27, 2018 Lower left wing panel. Looking at the rib cross-section, I decided to block up the spars with 1/8" balsa and the trailing edge plate and wing tip with 1/4" balsa. This appeared to work, but the trailing edge required two lengths of 1/4" square to support it properly. On the first letdown, I pinned through the spars. Danny, quite rightly threw his hands up in horror, so I scrapped those and supported the next attempt with 1/4: balsa each side. I laid down the rear spar first using a straightedge to ensure it was straight, then used the ribs to set the position of the front spar. Ribs were then added four at a time (I only have 8 engineers squares) using squares to ensure they were upright. Following the addition of the main ribs, the wing tips were added and when the whole was dry, the upper trailing edge 1/4" x 1/8" strip glued in place. I left the wing to dry for a couple of days, then removed it from the plan, added the first leading edge strip and the lower TE strip. I used a strip of 1/4" sq balsa inner the wing when pinning the last LE strip in place over a flat board to ensure a straight TE. My only deviation form he plan so far is to use spruce spars. The wing has turned out quite flat, so I'm still 'on the fence' in respect of spar webs. Note that the two root ribs are yet to be fitted (as are the three tip ribs). The latter will happen in due course, but the former will need the dihedral webs to be fitted which I'll do when I build the centre-section after completing the starboard wing. Edited By Andy Sephton 1 on 27/10/2018 19:50:56 Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 27, 2018 Author Share Posted October 27, 2018 Uper wing: I started to lay this one down this afternoon, but realised that I'd not planned the servo position - I'm using a separate servo in each wing. Danny also reminded me that I'll need servo lead holes in the ribs, which is another good call on his part! Accordingly, the plan was removed from the building board, the relevant bits copied and the servo position plotted: I'll be mounting the servos on two ply strips that run between three ribs. Edited By Andy Sephton 1 on 27/10/2018 19:54:56 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted October 27, 2018 Share Posted October 27, 2018 Great progress Andy, nice neat building too. So you are going to present the aileron pushrod as a direct replacement for the bellcrank output?I will probably do likewise. It is tempting to replicate the disc, but that is perhaps more trouble than it is worth.CheersDanny Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 27, 2018 Author Share Posted October 27, 2018 Are you going for detail again Danny.....it'll never catch on, mate! Yes, I'm planning to replace the bell crank with a servo. But having thought further, it doesn't need to be tilted. I can achieve the same result by off-setting the output arm on the servo shaft...doh! The next iteration should show a horizontal servo. Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 30, 2018 Author Share Posted October 30, 2018 I need to complete the centre-section of the lower wing in order to get the fuselage moving, the latter is waiting for the wing seat to be added. And in order to make up the centre-section, I need the second lower wing panel. The plan only shows one wing panel, so we need to build on the back of the plan for the opposite wing. Back in the day, AeroModeller used to recommend rubbing the plan with paraffin to make it transparent. With none of that in the garage, I use cooking oil or something similar. As this tends to ruin the original plan I make a photocopy that I can later throw away - I have a Brother A3 scanner/printer that will do A3 copies, and also enlarge and/or reduce them, which is very handy for a scale modeller! So, my technique is: copy the plan, tape the copies together to make one wing panel, cover the building board with cling film to protect it from the oil, lay the plan rear face uppermost on the cling film, rub the relevant parts with oil to make them show through, cover the result with cling film, them construct the wing. I start by laying a straight edge over the spar position and add blocks on one side. I then add the spar and use blocks the other side to hold it in place. The position of the second spar and TE can be set using wing ribs to get the required distances. When adding ribs, I use engineers squares to keep them all upright, so I can only add four at a time. I use to do that by eye, but since I now wear various-focal lenses, trying to assess anything by eye is a nightmare!!! Anyway, progress has been steady and the lower photo shows the result after adding the TE strip and the wing tip this morning. For info, the spars have been jigged off the plan with 1/8" scrap, and the TE and wing tip using 1/4" scrap. The 2 root ribs require the dihedral braces to be fitted first, so they will wait until the centre-section is constructed. Edited By Andy Sephton 1 on 30/10/2018 09:52:28 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 30, 2018 Share Posted October 30, 2018 Looking good Andy I'll be interested to know how you get on with those 3 wing tip ribs. Still the bane of my life Edited By Martyn K on 30/10/2018 11:02:10 Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 30, 2018 Author Share Posted October 30, 2018 Thanks Martyn. I'm leaving the tip ribs for the mo as the priority for me is the lower wing centre-section so I can progress the fuselage. I'll post when I've had a better look at them and come up with a solution. Edited By Andy Sephton 1 on 30/10/2018 11:47:36 Quote Link to comment Share on other sites More sharing options...
alan p Posted October 30, 2018 Share Posted October 30, 2018 If you have grand kids or even older offspring Lego comes beautifully accurate square and can be built to suit application. And they might not miss a few pieces. Quote Link to comment Share on other sites More sharing options...
alan p Posted October 30, 2018 Share Posted October 30, 2018 If you have grand kids or even older offspring Lego comes beautifully accurate square and can be built to suit application. And they might not miss a few pieces. Quote Link to comment Share on other sites More sharing options...
Silver Wolf Posted October 30, 2018 Share Posted October 30, 2018 Nice idea with using scraps of balsa as clamps, maygive that a go, likely to use servos in wing aswell. Regards SW Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted October 30, 2018 Share Posted October 30, 2018 Andy, I found with the Chipmunk that rubbing the plan with meths made it transparent without shrinking the paper and leaves it completely dry. It lasts that way as well. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted October 31, 2018 Share Posted October 31, 2018 I use Linseed Oil to make the plan transparent. It works a treat and has the benefit of making the plan non stick. It also smells nice and workshoppy Martyn Quote Link to comment Share on other sites More sharing options...
Richard Mallam. Posted October 31, 2018 Share Posted October 31, 2018 Hi Andy, I have just asked Danny this question, but as he is going electric and I am (like you) going IC, where will you be positioning your servos for the rudder and elevators, since you say that you have a fuel tank which fits nicely behind the firewall? Thanks Richard Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 31, 2018 Author Share Posted October 31, 2018 I'm aiming to get four (or three if I can't fit four in) servos immediately behind the firewall. The fuel tank only takes up half the vertical space in the first bay, so there's more than adequate room for the servos. If I can, I'll squeeze the flight battery in alongside the tank. I want to keep the heavy stuff as far forward as I can to reduce the need for nose ballast. The four servos are because I want to have a servo on each elevator so that I can use differential elevator to enhance the roll rate as it is, reportedly, quite slow. The full-size was similar. The receiver will fit into the cockpit area with a suitable switch. Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted October 31, 2018 Author Share Posted October 31, 2018 Edited By Andy Sephton 1 on 31/10/2018 19:21:14 Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted November 1, 2018 Author Share Posted November 1, 2018 The two lower wing panels are now off the board; they both need work but they'll do to set up the centre-section. My building board is too small for the complete wing, so I'm using a couple of balsa blocks to prop up the wing at the correct dihedral angle. The spars and leading edge at the centre-section have been jigged up with scrap 1/8" and the TE with scrap 1/4". I've started to build up the two spars using 1/8" x 1/4" spruce and scrap 1/4" balsa to fill. I've also added the LE dihedral braces, B4. On a first look the 1/16" ply dihedral braces are a mite too long, but I'll pare those down before I fit them, which will be after the current work is dry. Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted November 1, 2018 Author Share Posted November 1, 2018 I was in communication with Danny this afternoon when he asked me to post how I'd jigged the centre-section and outer wing panels. The centre-section spars, LE and TE were blocked up with scrap balsa as in the previous post. I worked out the position of the dihedral support block by cutting a length of balsa to 1 7/8", the height of the lower wing tip at the correct dihedral angle. Taking one wing panel, I blocked the spars off the bench at the root by 1/8". Had the root rib been fitted, it would then be just touching the building board. I blocked the tip up by 1 7/8", then slid the block along the wing until it touched. The position was marked and then used to support the wing panels at the correct angle. As soon as the spars in the above post were dry, I removed most of the pins, shaved the edge of the ply dihedral braces to fit, and glued them in position. The photos show them clamped in place. The second photo show a dry fit of the rear centre-section ribs. Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 1, 2018 Share Posted November 1, 2018 looking good Andy, and thx for the detail Cheers Danny Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted November 6, 2018 Author Share Posted November 6, 2018 I've been working slowly but steadily on the lower wing centre-section since the last post. I was stuck for a method of jigging the parts and after much thought, decided to build the centre part over the plan. It's constructed from 1/8" ply, so pinning was out. In the end, I opted for my trusty engineers squares and some steel bar stock that's been hanging around the workshop for some time. There's a centre-section assembly under there somewhere: This is what it looks like right side up, but with the weights and supports removed: And this is how it was built, upside down over the plan with a 1/16" support strip under the front end to allow the ply plates at the rear to lie flat on the plan. I'm grateful to Danny for reminding me (before the glue had fully dried) that the open areas go on the outside. They are there as rebates for the UC leg and mounting brackets. The next pic shows the above assembly glued in place. I needed to shim the spar with a piece of 1/64" ply as the centre-section assembly was a mite too small chordwise. I'm not sure why this occurred as the parts were laser cut and the spar position should be constant throughout. Next job was to add the rear ribs: The front ribs were next. The full length ones required 1/64" shaving off to fit (so it must have been the front spar that was too far forward!). The outer ribs needed a further 1/4" shaving off for the dihedral brace - this was not shown on the plan. The balsa ribs were then cut to length and added at the root of the wing panels Leaving me with: and finally, the gap between the ply centre-section ribs at the spar positions was filled with some scrap 3/32" balsa to give support to the 1/16" covering that will be fitted later. I has planned to put a Laser 70 in the model, but with so much advice saying that it won't be powerful enough, I needed an alternate. A visit to the Gildings Model Engine Auction last Saturday saw me returning with a Laser 150 (and several other goodies...). I'll still fit the 70, but the 150 is there, just in case. The engine auction turned out to be a great day out with like-minded mates with bargains for all of us in the form of engines, kits, modelling wherewithal, tools and ready built models. I'd recommend that you join us next year ...... but if I did and you took up the offer, you might end up bidding against me..... Edited By Andy Sephton 1 on 06/11/2018 07:00:28 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted November 6, 2018 Share Posted November 6, 2018 Fabulous post Andy, that makes that part of the wing very clear for those of us yet to tackle this part.CheersDanny Quote Link to comment Share on other sites More sharing options...
Andy Sephton 1 Posted November 7, 2018 Author Share Posted November 7, 2018 I've used relatively hard 1/16" balsa for the sheeting and Aliphatic Resin for the adhesive. 3" sheets go round the curves quite nicely, held in place with 1/8" scrap balsa, clamps and pins. When dry, the pins, clamps and scrap balsa was removed and the front end flattened using a sanding block. The 1/4" balsa LE could then be stuck and pinned in place. When dry, I shaped the LE using a razor plane and sanding block. The ply fuselage doubler was used as a handy guide to the shape. ...and finally, I couldn't resist a quick trial fit in the fuselage, which I was quite pleased with! Next job will be the lower wing seating in the fuselage, which will allow me to progress with the latter. Quote Link to comment Share on other sites More sharing options...
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