Posts Tagged formers
Final version of the wing spars now cut using 1/8″ Ply based off of the templates finished over the weekend and offered up to the fuselage. They fit just a bout perfect first go, with just a little light sandpapering needed. Then it was on to making the final cuts to Wing
former 1 (W1) which attaches to the fuselage and has cut outs to allow the entire wing assembly to be removed. Next it was on to formers 2-6 (W2-6). a little adjustment was needed to allow them to slide onto the spars with the minimum of interference and to allow the engine housings to line up correctly. I’m pretty happy with the dihedral but, it will become more apparent as the rest of the wing assemblies are fitted.
Next jobs to be completed include the fuselage side of the bolts to hold the wing in place, not sure whether to go for rivnut type fittings on the fuselage side or just nut/bolt.. After that I need to cut out the engine parts for the other inboard engine. get the starboard wing built and then connect them to the wing root. So much still to do!!
I really will need to get on to building a vac-forming machine ready to form the nose cone and other parts that are going to be needed. Anyhow it’s starting to look a bit more like a bomber now..
Well the wing root is coming along nicely. I’m still using the lite-ply template pieces for the wing spars, as there’s continued fine-tuning as i get the next wing former added. I now have out to wing former 5 (W5) fitted on the right side of the spar and the first 3 (W1,2,3) fitted on the left. A test fit of former 6 (W6) on the right side and there’s a small amount of adjustment to do and that should be it. Then just need to replicate to the left side and fit the formers and we should be done. Next up is to check the fitting into the fuselage and then take it all apart and cut the real parts using 1/8″ ply. Hoping to get that all finished this week.
Cut out some templates using lite-ply of the wing root spars (WSP1,2,3 on plan) and test fit the first wing formers to them. There’s some work to do on them as i start adding the the next 3-4 wing spars, but first fit they are pretty close. A little bit of fettling to get them to mate up to the fuselage and then once i’m happy i can cut the production pieces in 1/8″ ply. While on the subject of wings i also started to build up the left hand wing structure, have about half of the formers cut and in place ready to be glued onto the spars. I’ve a few more to template and cut to get to the same point as the right hand wing. As well as the wing root formers which are all in 1/8″ ply. These are taking a little while to complete as i’m having to cut the slots with the trusty chisel.
In between the wing work i’ve been researching building a small vac-forming set-up. As i’m going to have to build the nosecone, belly turret and top turret. It seems that some vac-formed pieces would be the way to go. Also spent some time researching how to build a home CNC/Laser cutting setup as well. I feel this will give me far more accurate pieces than using the skill saw. Theres some great designs i found on Openbuilds website. it doesn’t look to difficult to build.
Well, hoping to progress with the wing root templates this week. thers a lot of other jobs that can then be completed once this is done and t ewings are attached.
The fuselage formers are now all glued to the central 3/16″ crutch, and the Tailplane former. Next jobs on the list are to add the ribs to the tailplane section to make it more rigid, then to start cutting and gluing the stringers around the fuselage. I’ve marked the locations of the nose and waist gun positions to ensure i don’t mistakenly glue stringers across these areas. Keel crutch has also been added from the rear former through to the rear of the bomb bay. Also on the list of jobs to complete is to attach the cab roof section to the formers.
Yesterday was the turn of the tailplane to be test fitted to the fuselage. The distinctive B-17 tailplane was formed by splicing 3 pieces of 1/8″ balsa together. It fitted reasonably well first go, with just some minor sandpapering of slots that were slightly tight. With the tail assembly attached this completed the main fuselage. Now we move on to gluing the fuselage together, ensuring it stays as straight as possible.
With all of the fuselage formers and tailplane parts cut the workshop can now fall silent, except for my ramblings and some music. Hopefully more tomorrow as i get the fuselage glued together.
Now have all of the fuselage formers cut out. Just got to notch out where the longerons fit. So thought i’d test fit all the formers to the 3/16″ crutch. Still a lot of work to be done before it can all be glued together permanently. The photo only shows formers 1 thru 14 in place. I’ve still to cut the crutch notches out for the remaining 5 formers before attaching them.
I’ve started thinking about how best to attach the wings to the fuselage for easy transportation. The original plan has the wing as a single piece construction removable by unbolting the wing from the fuselage via the bomb bay.However looking at the diagrams, there seems to be longerons spanning the length of the bomb bay, which would make it impossible to remove the wing. I’m currently thinking of making this a 2 piece wing joined to the fuselage using carbon fibre spars bolted via the bomb bay.
The last couple of days have been spent tracing out and cutting the fuselage formers. The plans called for a mix of 1/8″ ply and 1/8″ balsa to be used. However the widest sheet of balsa i can get anywhere is 4″. This is not wide enough for the formers, I’ve.taken the decision to change this to lite-ply. Although this will make the fuselage slightly heavier it should be pretty negligible. At the current pace I should have all of the formers completed in the next couple of days.
I’ve been thinking about building the fuselage on some form of jig to ensure straightness. My current thoughts are to use some 4″ blocks of wood with spacing controlled by a dowel or metal screw rod. This would maintain squareness of formers, and then just pin the centre crutch to the blocks to keep horizontal squareness. Anyway I’ll continue to play with this idea and post up a picture if it works out.