Festivities Gone!!!! Hurrahhh
Finally with the festive period well and truly scrapped, the more serious subject of updating the progress of the B-29 Superfortress can now continue. I hope you all had a great Christmas all the same
Now then, since my last update, a rather large chunk of the bomber has been done, in my standards anyway. You will recall on my final chapter before the festiities arrived I was about to sand the front section of the fuselage ready for skinning. This has now been done and I decided to plank the structure diagonally using 1/16 sheet balsa strips 1/2 inch wide. This has proven to be successful, albeit a rather long process.
The six images below show the process from start to finish before trimming. The more difficult areas were around the wing root section of the fuselage. For this area I planked upto the root and cut the strip at 90 degrees where it met the root, leaving me small elongated triangular sections to fill after. Because the surrounding areas of he root between stringers was filled with 1/8 sheet, this gave me a solid surface to CA the triangular sections too once cut to size.
This set of six images show the fuselage sections bolted back together. Some of the triangular sections still need to be added and the planking trimmed. This bolting back together process was merely a test to check planking the front section had not bent or twisted the framework and as you can see it is all still good. One slight alteration or modification I did however make was were the two sections join, I noticed a small amount of movement vertically was present. So I decided to drill two 4mm holes opposite one another at the top and the bottom of the formers that butt up together. I then cut out four 1 inch square 1/8 ply sections and also drilled these with a 4mm hole through the middle. I then Epoxied a 3M nut over the hole on two of the ply squares and again epoxied these to the inner areas over the holes on the rear sections former passing a 3M bolt through the hole to keep it all lined up. I then repeated the process on the other two 1 inch ply squares, this time with a 3M 1 inch diameter washer. These were then epoxied to the inner sections over the holes on the former on the front section of the fueslage, again using a 3M bolt to keep it all lined up. Once the epoxy set, I slid the two sections back together and bolted it all up. As well as the 6mm bolt in the middle, the two new 3mm bolts now made everything strong and movement free. Slight cutting away of the inner sections of two of the formers in the front fuselage section was needed to allow me access to the new bolts but has not altered the strength of the model so all is good.
Once again I added the tailplane and fin to the rear section dry, just to stand back and look at the progress of this monster model. The last image you can just see the 1 inch diameter washer and 3mm screw bolt head, just below and left of the main centre 6mm bolt.
The first image you can see the ply plate that travels from the front former back through the second and third formers that the front retract bay is epoxied too underneath. This ply floor will also make for good Lipo battery positioning incase I need to shift the CG forward more after set up.
The following images are of the building of the rear bomb bay doors. These were made by using the inner walls of the bay area to get the correct curve for the doors. Four curved sections were made and a sheet of 1/16 x 4 was cut too length and scored all the way down 1/4 inch apart. This allowed me to acheive a curve in the sheet. I then glued the four sections to the sheet and allowed it to dry. I then marked the centre point of the hatch and carefully cut it down the middle seperating the two doors. This was then followed by trimming back the curved sections to give me a better looking less drag free door when open in flight. Test fitting to the bomber was then carried out and at was great, although one door did need a little steam and a twist to remove a peskie warp but it all lined up good. Don’t be, like I was, put off by the seemingly totally out of line bomb bay doors in the image where they are shut. It is what I think they call an optical illusion because the direction I have planked the fuselage. Trust me, I measured, lined up, angle checked, god knows how many times before I was convinced haha
Anyway thats it for now guys. For all you weight watchers out there, total all up weight of everything constructed so far……… 455grams (16.0ozs)
Following on, I noticed that the front oleo strut just above the top of the wheels, was kinked rearward where the suspension knuckle is! Well this changed everything! I modified my excellent mock up wheel strut, basically snapped it where the knuckle was and bent it back to the required angle and look what happened….. it retracted fully into the bay! 😀 Happy Rob was an understatement 🙂
Anyway with that all sorted, the front retract bay was contructed, firstly from 1/16 balsa to make the templates, then when happy it all went together properly, these were duplicated in 1/8 ply to make a box section. The very front was cut away to allow fitting the box but slots were cut into the first to third formers mid way down and a 1/8 ply base was epoxied into place for the retract bay to be glued too, A ply front wall for former number one was also added to give strength to this area and once glued and postioned and lined up, it was heavily epoxied in place.
I have now been thoroughly sanding the whole fuselage and I am about ready to start skinning her.
And thats it for now guys. Hope you are all enjoying this build as much as I am. I fear it is ripping along rather rapidly. At this rate I will soon be thinking about what other large model aircraft I can build…….Tiny hint…..in the pipeline an Avro Shackleton 😉
So here we are again finally with an update on the B-29 🙂
After successfully seperating the two fuselage halves, with no twisting of either thankfully, I was able to divide the front and rear sections also without issue, I was able to drill and add the aluminium tubes and dowels for joining the two sections after transporting. The alloy tubes were located in the forward section with ply reinforcing and the two front fuselage halves glued thoroughly back together and then the upper decking was added where the electrics will be placed once all was dry. The dowls were then added and again reinforced to the rear section and again the rear fuselage sections glued back together. Once dry I test fitted the front and rear sections to make sure all lined up perfectly and they did 😀
Next a horizontal plywood bracket was made for each side of the two halves with spacers fitted and these were drilled with a 6mm dia hole for the wing bolt being used to pull the two sections together. The steel bolt you see is just temporary until I can get hold of a proper plastic bolt. As you can see from the following shot all goes toether well.
Next it was time to fit the bomb bays, so I seperated the two sections and turned the fuselage over. A very basic box was added to the front bay more to keep it strong in that area really although it will still look good once finished and still have operating doors. Likewise for the rear bay, however this was slightly modified as it is going to be the area I use to allow access to the rear fuselage joining bolts. Constuction was the same apart from the large section cut away for the access. Another floor panel was then made and added over the top held in place by four small self tappers in each corner. The tiny holes were drilled for these screws and then I added CA glue to each to harden the wood and stop it splitting. Again as you can see from the picture it looks fine.
Then it was time to add the front wheel bay. Now, you may recall I was having issues regarding the front wheel alignment because the oleo on a 29’s front leg is forward of 90 degrees. Keeping it scale, I was having issues with the wheel retracting in the full size tacky mock up I made. Positioning the retract unit at an angle to compensate for this meant when the wheels retracted, they hung low out the fuselage so this meant the bay doors would not shut. You will see what I mean in the last two images here………….after studying closer at image of the full size bomber, an ‘Oh my god’!! moment errupted
Continuing on from yesterday the fuselage is coming along very nicely.
The fuselage formers on the opposite side have been lightly glue tacked into place and also 1/8 square strips added to keep everything straight. Then I added the side keel and wing root and followed on with the slow task of adding all the stringers once again. The polystyrene box with the semi circular sections cut out aided me well during this process of the build enabling me to rotate the fuselage as I worked my way around the airframe.
12 hours later and we have a fuselage, resembling what can only be described as close as I would get to a framed model of the Zepplin airship Grin
Anyway now dry, I will cut out the upper hatch out that will give me access to the wing securing bolts and electrics then I will split the two halves apart very carefully I might add and then I will be adding a bay floor as well as making the bomb bay and front retract bay and making the neccasary adjustments to fit them plus adding the aluminium tubes and dowls where the fuselage splits for transport before glueing the two havles permenantly back together with 30 minute epoxy
I couldn’t help but place the tailplane and fin on the aircraft and stood back. It looked well impressive……and big! As for weight watchers, airframe as done here – 258grams. Total all up weight of all build sections together – 443grams (15.5ozs)
Anyway more to follow soon guys
Rob
Finally after three days I’m back with the progress of the B-29 🙂
Fuselage
Right here we go. Finally after a couple of days tracing and cutting out we have the construction of the fuselage under way. In order as they are here first we have laid out on the floor on top of the reference plan all the wood cut out and ready to go for the fuselage. Next procedure was to lay out on the plan the centre keel upper and lower sections, These were pinned down and CA glue was used to join all six sections, three on top three on the bottom.
I then followed on with gluing all the 22 formers in order but leaving off the front number 1 former, becasuse this cannot be glued in place until the side keel is added. Once the formers were set I then added the side keel and former number 1. This was where the first of two times I was bobbing it incase it didn’t fit very well. I must of done something right because it did fit and it all lined up perfectly.
I then added the wing mount section, part two of bobbing it cause again was worried it didn’t fit. Wrong again 🙂 It droppped straight into place and lined up spot on. The slots you can see are for the wing braces. These are 3/16 ply x 2 and will slide into box sections glued to formers 7 and 8 and then held in place by two removable bolts, so the wings can be removed for transport perposes of coarse 🙂
Once happy all was dry and lined up, then it was onto the ridiculously boring task of addin the stringers, all 25 of them! Anyway as you can see this is where I am now. I will leave it too dry for the day and then I can remove it from the plan and review the location of the front retract bay and bomb bays. The rear bomb bay will be mainly for access to the fuselage join bolts just aft of the wing. This is held in place by four 6mm dowels passing through formers 13 and 12A, going into aluminium tubes located in formers 12 and 11 and again secured with two bolts.
So there we have it. Well chuffed and steaming along. More to come hopefully very soon 😀
Once this section of the fuselage is dry and I can remove it I will turn it over and place it into a specially made jig (basically two thick bits of polystrene with semi circular sections cut out 🙂 ) and then I will build ontop of it the other half, however this will actually only be tacked in place because once done and dry, I will be splitting the two sections halves apart again so I can continue with the interior sections that need to be added like the front retract bay and the dowls for the fuselage join etc. Back soon.
Rob
Anyway onwards and upwards as they say. Time for a few more images…….
The first image (thats provided they upload in the sequence I picked them) shows the hinge fitted at the lower of the fin. You can see where the three holes from the hinge stick out. Here I will be sliding 3 cocktail sticks and epoxying them to the back section where the hinge comes out. The next shot shows the whole fin and rudder assembly hinged together (dry) followed by the home made control horn. This is made from aluminium with holes drilled in the ends for the rods. A slot was cut in a section of measured to fit 1/4 x 1/4 balsa where it was CA glued in place then over the face of the balsa a piece of 1/16 a 1/4 ply was glued to hold it in. The whole thing was then soaked in CA glue and left to harden and then glued to the back face of the rudders leading edge as you can just see in the next shot but clearer in the one after. The rods were then connected to the servo and the control horn as you can see and it was tested……………it worked!
Progress has been good. Sheeted the fin in 1/32 sheet. I roughly cut the shape out for each side ( note the grain direction) and used CA glue to join them together over foil and no I’m not covering the model with kitchen foil before someone asks haha I then glued them to the frame of the fin. I started at the trailing edge of the fin running CA down the spine and then glued it to the ribs rolling the skin down as I worked my way forward to the leading edge then finished by glueing the bottom then repeated for the other side but cut out a panel for access to the servo beforehand. Getting to the servo is now easy and enables me to make any adjustment including removing the servo if needed.
Final Image shows the completed fin and rudder prior to sanding the edges round. Very happy and oh yea and all up weight 80grams so far
Tailplane and elevators
The tailplane has two spars, the rear straight and the front angled and is a one peice section that is tapered to the tips and also has a slight dihedral built into it. You can see the tabs on the spars used to keep the dihedral accurate while adding the ribs. This also eliminates warping. The ribs are cut out as complete ribs however after fitting, the six inner ribs have the rear sections cut off and the tip rib and inside but one rib have the rear sections copied. These are put too one side and used later to build up the elevators.
Next the leading edge was added along with the tip blocks and trailing edges. The trailing edge is glued to the rear of the tips and last three ribs and when dry cut flush with the tip rib and inner rib. This then becomes the trailing edge for the elevators. Once dried the whole frame was turned over and the carbon fibre rod fitted to the lower of the main spar and epoxied into place.
The sections cut from the rear of the ribs were then glued to the trailing edges and trimmed. 1/4 sheet front leading edge sections tapered were then fitted where the hinged system will go. These were then sanded to shape and lined up with the tailplane. Fitted perfectly 😀 I couldn’t resist placing the fin and rudder on top and then visualising haha but god it looks epic!!
The tailplane was sanded to shape and the skin for the underside made from 1/32 sheet and joined as before like the fin and applied, again rolling it down from the trailing edge to the leading edge and went on without any issues. This was then trimmed.
Thats as far as I have got so far. Next will be fitting the servo’s and making the mounts for the control horns on the elevators followed by skinning the top.
Back later with the rest of the progress then its time to start the fuselage
Rob
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