R/C 108" Wingspan B-29 Superfortress build

By: robmac - 7th December 2013 at 10:44 Permalink - Edited 1st January 1970 at 01:00

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 :D 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

By: robmac - 8th December 2013 at 03:22 Permalink - Edited 1st January 1970 at 01:00

I am going to really enjoy following this, thank you for sharing.

Your welcome :)

By: robmac - 9th December 2013 at 06:59 Permalink - Edited 1st January 1970 at 01:00

Same! And an ignorant Q if I may - what is CA glue?

Well didn't have to answer that one for you as the guys already did :)

Your gonna hear and see all sorts of weird and wonderful words on this thread but I'll explain as I go :)

By: robmac - 10th December 2013 at 06:51 Permalink - Edited 1st January 1970 at 01:00

All way out of my league but a fascinating thread, which I will follow through to first flight!!;)

No pressure then Charlie? Haha :D It will be a while before she flies but aiming for the end of April beginning of May time, just in time for the calm warm days :)

By: robmac - 12th December 2013 at 01:07 Permalink - Edited 1st January 1970 at 01:00

Just wondering; no criticism intended but looking at the pictures of the fin and rudder again I suppose you will sand the leading and trailing edges to section because they look a bit blunt at the moment.
Talking of sanding I would wrap the servo plug end in some masking tape to stop dust getting in the electrics.

Yea the fin isn't quite finished yet, nore is the tailplane. Both need to be sanded to shape properly and the servo has film over the plug. Don't worry I have been doing this for years and have discovered issues like that in the past. Never make the same mistake twice :)....although saying that back in my early days I did actually turn the receiver switch off while hand launching two models on seperate occasions, the one, a small scratch built Hurricane, flying into a wood at the end of the field and the other, a rather nice Jap Zero, flying off into the distance never to be seen again! So it can happen :/

More images of the build coming up in a wee while :)

By: robmac - 12th December 2013 at 05:38 Permalink - Edited 1st January 1970 at 01:00

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 :D

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

By: robmac - 13th December 2013 at 19:31 Permalink - Edited 1st January 1970 at 01:00

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