Posts Tagged Bomber
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.
With Saturday being taken up with work in the morning and an afternoon watching the cricket world cup, this only left Sunday to work on the B17. One task was to shape the steering arm for the rudder.This was made from 3mm Piano wire. I’ve still to fabricate a brass control horn and solder this to the Piano wire. There is also a second mount bracket to fit further up the tailplane to help support the steering.
This just leaves me with a decision on how to build the rudder itself. I’m torn between using a thin balsa core or to make it hollow just using formers for the shape. But that is on the to-do list for this week.
The second major task that progressed this weekend was the construction of the stabilizers and elevators. Both Stabs have been built now as have both elevators. Just some shaping of the leading edges to be done. Again the steering arm for the elevators was made from 3mm Piano Wire bent to shape. The far end of the elevators is held in place by a metal pin made from a length of piano wire inserted in the stabilizer and elevator.
Separately from the build i was having a wander through a bookstore in town, which happens to have a small section on military aircraft, and came across a nice little book. The book is called Bomber Command and is a great colour reference of WW2 Us Bombers.
Progress continues adding the stringers to the fuselage, although i did run out of stock of 1/8″ x 1/8″ balsa stick. So a trip to the nearest model store for supplies saw me clear them out of their paltry supplies. This allowed me to add a few more stringers to the rear section, forming up the tail wheel area and the waist gun areas.
Stock was running low yet again so i thought it better to start to build the stabilizers as these also need 1/8″ x 1/8″ strip stock. As well as fitting into the rear section before i get much further along in the build.
The keen eyed person may have spotted the model PBY Catalina ‘black cat’ on the bench. I also have R/C plans for one of these.. Space permitting it my be the next build!
Another trip to my backup model store will be in order in the next couple of days as yet more 1/8″ x 1/8″ strip is required, as well as material for leading and trailing edges of the stabs. The stabilizers are built as two parts with the spars butting up against each other inside the fuselage. Once built and test fitted i think they’ll be bolted against at least one of the fuselage formers.
Also started to look at the mechanism for turning the rudder. The plans have this as a totally enclosed structure within the rudder itself. A control horn will need to be brazed onto a wire and fitted inside the fuselage, and then extended up through the rudder. A similar mechanism will need to be constructed for the elevators.
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.