Simplified version of the classic biplane
Martin McIntosh | 23/05/2020 15:33:17 |
![]() 3701 forum posts 1294 photos | Now got quite a bit further. Formers and super light stringers added and the temporary spacers removed. The crankshaft is in about the right place as it will exit the cowl with maybe just a little shimming needed. I can now get on with the cabane mounts. 1/8th birch ply would give me the right depth for the 10g wire but I would prefer to use 3mm light with some 1/64th birch to build it up a bit, also some 1/32nd on the inside of the fus.
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Martin McIntosh | 23/05/2020 19:08:21 |
![]() 3701 forum posts 1294 photos | My way of fitting the cabane wires.
A little adjustment will no doubt be necessary when I come to fit the top wing. |
Nigel R | 23/05/2020 22:53:47 |
![]() 4414 forum posts 717 photos | Blimey you're not hanging about! All I did this evening was cut my three main formers: |
Nigel R | 23/05/2020 22:54:51 |
![]() 4414 forum posts 717 photos | The angles were done just so:
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Nigel R | 23/05/2020 22:58:00 |
![]() 4414 forum posts 717 photos | I'm doing the front deck from some soft thick stuff. A carve and sand exercise. My second former back is cut to match the fuselage side. I'll put a deck former on top after the main box section at the front is all jigged and glued. That way I can build most of the fuselage upside down flat on the board. |
Martin McIntosh | 24/05/2020 10:45:23 |
![]() 3701 forum posts 1294 photos | You must be building a completely different version, all of my formers are rounded. How do you intend to shape the forward decking since the cabane struts need to be fitted first? With less meat in the fus. sides I shall have to do some filling in with strip to fit my decking formers. I only too well remember my Stampe being a little awkward to do in this area. |
Martin McIntosh | 24/05/2020 21:14:10 |
![]() 3701 forum posts 1294 photos | I little more done today, 3/16 wing seat doublers, some trianglular where the u/c plate will go, wing LE former to take a tongue, rear wing bolt plate and the front deck formers with stringers ready to sheet.
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Nigel R | 24/05/2020 22:38:55 |
![]() 4414 forum posts 717 photos | Martin yes the cabane arrangement on mine attaches permanently after covering. It is not fixed in early in the build. That means I can build the fuselage without bits of wire getting in the way. I'm still playing with the formers...
T nuts were too deep for the 1/4" ply so I turned up some 1/32" discs to make up the depth.: Edited By Nigel R on 24/05/2020 22:40:11 |
Martin McIntosh | 25/05/2020 10:26:18 |
![]() 3701 forum posts 1294 photos | I get round the T nut problem by making firewalls from 6mm liteply then facing the front with 1/16" birch. I did not recognise your formers because the angled one is the firewall, quite different to mine. |
Martin McIntosh | 25/05/2020 18:03:45 |
![]() 3701 forum posts 1294 photos | Tail started and top deck added. This actually went on quite well for a change. I would normally build wings first to get them out of the way but since I wanted to make the fus. simpler I have gone down this route. At least I have most of the ribs cut ready but again I shall be changing the construction a fair bit.
Edited By Martin McIntosh on 25/05/2020 18:05:12 |
Nigel R | 25/05/2020 22:59:03 |
![]() 4414 forum posts 717 photos | That is looking good Martin. |
Nigel R | 01/06/2020 10:04:56 |
![]() 4414 forum posts 717 photos | Small progress this week; a few repairs on the fleet have taken the normal workbench time away from building. I rough cut my fuselage sides and doublers: The datum line (the top straight edge of the sides and doublers) is cut as accurately as I can. As is the rear angled cut on the doubler. The other cuts are simply "large enough" to trim down to size. Note small forest of toothpicks holding everything neatly aligned. I also had to join some bits of balsa together to make a wide enough sheet, these things are about 5-1/4" wide around the wing saddle. Next, I got the doublers stuck in place with contact adhesive. I put it on with a credit card to scrape it out nice and thin. It was measured out using a 10ml syringe which also makes distributing it across the face of the joint easy. Each doubler needed 5ml on each face of the joint. Easily done with the syringe. When scraped out, the adhesive dries in seconds, in the warm weather we are having. Again, lots of toothpicks to keep it all in alignment when pressing the joint closed. I then started cutting the oversize bits down to proper size: The top of the fuselage side and top of doubler had come out nicely lined up (phew), so the next move was to get both sides together to run the sanding block around and get them as identical as possible: The remaining job here is to cut the wing saddle out. Then I can start thinking about getting the formers and sides into the jig to glue it all up. You might note my sides look a bit different to Martin's. I am not doing the stringers on the rear underside - I am making my fuselage a little more like the Bi Fly, with a standard sort of sport type 'box' build, where the underside is sheeted with some cross-grain wood. See here:
Edited By Nigel R on 01/06/2020 10:18:01 |
Martin McIntosh | 01/06/2020 13:42:11 |
![]() 3701 forum posts 1294 photos | I have been building the top wing and since there will be four ailerons I have shortened them to outboard types. I found these a little tricky to make since that part of the wing construction is different to the way I normally do it. I have not used any of the small fiddley bits of ribs, in fact all of mine are identical. Just got to the stage of butt joining the halves ready to make up and fit the scarfe joints. Very rigid and light so far. |
Nigel R | 01/06/2020 14:48:31 |
![]() 4414 forum posts 717 photos | Hope your ailerons turn out better than mine did! I made a right fist of that part of the build... How have you done the 'edge of aileron' area without riblets? |
Martin McIntosh | 01/06/2020 16:12:08 |
![]() 3701 forum posts 1294 photos | I built the basic wing half with spars and shear webs then sheeted the top front and the aileron top. Double ribs spaced 1/16th apart at the aileron root and tip. I then marked the aileron underside with the chamfer ready to face with 1/8th and similarly faced the aileron cut out on the wing. My ribs taper at the TE almost to a point so when the rest of the sheeting was applied I just glued the sheets together here and dispensed with the 1/2" TE piece. Horn and hinge areas were done with bits of 1/4". Too late to show you now but will try to remember to take some pics of the other wing. |
Martin McIntosh | 03/06/2020 21:37:23 |
![]() 3701 forum posts 1294 photos | An update on my bottom wing. I decided to sheet the upper surface only on the tips because 1) any more would just add weight and 2) I got fed up doing it. I have the ply plate installed for the wing bolts and one servo mount. Because there is no dihedral and I have extended the centre sheeting straight across there is no need for bandage. I have cut away the TE a bit to fit since my method of construction made the chord a little broader. When this is finished I only need to do it all again!!!
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Nigel R | 04/06/2020 11:42:16 |
![]() 4414 forum posts 717 photos | Quick work again Martin. That is going to have a lot of aileron area with four ailerons that size! I'm curious about the sheeting, doesn't the plan show the main panel D box (and TE) sheeting extending right to the central rib?
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Martin McIntosh | 04/06/2020 12:04:17 |
![]() 3701 forum posts 1294 photos | I built the wing halves first, then added the centre which may explain why my sheeting looks different. Bottom wing now completed, so just have to do it all again. |
Martin McIntosh | 04/06/2020 21:42:36 |
![]() 3701 forum posts 1294 photos | The way I made up the ailerons using R1 throughout.
basic structure first removed and upper sheeting added aileron bevel marked out ready for cutting then facing with 1/8th a facing part and some 1/4" to do the hinge and horn reinforcement |
Nigel R | 05/06/2020 08:48:59 |
![]() 4414 forum posts 717 photos | You're certainly pressing on. Complete airframe next week!? Slower progress here. Limited workshop time has recently gone on sorting out some small issues in the rest of the hangar (slack solarfilm, the odd loose UC clamp, that kind of thing). Jobs ticked off were, motor on mount: It has wound up being 5-1/2" from firewall to prop driver. And I carefully sanded out the wing saddle (dremel and some tidying with paper wrapped around dowel): it's ever so slightly larger all around, giving a bit of space for glass bandage and a tickle of RTV. Anyway, enough kitting up, I'm now ready to start getting the fuselage built up in the jig. |
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