Paper on Balsa

Discussion in 'Aircraft & Aviation' started by scon10, Dec 2, 2007.

  1. scon10

    scon10 Member

    I have been asked in a German forum to post a description of how I build my models from scratch, using a balsa framework, to which paper panels are attached, giving a nice "constructed" feeling to the model. I posted this thread also on that German forum, but perhaps I did something wrong, for it was not uploaded. I'll try it with this forum and see how it goes.
    First, I start, as with all projects, with some research. In this case I need an accurate side view of the airplane, the wingplan and for the engines, a copy of the Schreiber card model of the Swissair DC-7C. I am building the Douglas DC-6B in KLM colours, and in the manufacturer-issued Douglas Service I found a clear picture of the fuselage and wing stations, wich I scanned and printed to scale 1:50. In view of the size of a DC-6B in 1:50 (around 64 cm), this comes on two A-4 size sheets, see picture 1. I glued the side view on thin balsa, 2 mm, and cut out the shape, to use it as a centre part, as a backbone as it were. Since I am going to make the passenger windows transparant, I also cut out various areas of the center part, so that you can see through from one side to the other.

    I also copied the bulkheads of the Schreiber Swissair DC-7C and glued these, as well as the fuselage side view, on thin balsa planks, 2 mm thick. From this, I build up the fuselage frame, glueing the bulkheads on both sides of the centre part, at regular intervals, I chose 4 cm, which is the space between 2 windows in a row. See the picture which shows the attached longerons. I will explain in a next post how I did that.

    That's it for today. It is Saint Nicholas Birthday festival in Holland, so I have to help him prepare gifts and poems for the family.
    Best regards,

    Attached Files:

  2. mikew

    mikew Member

    It looks like this will be a very interesting build/tutorial. Thank you for sharing.

  3. BARX2

    BARX2 Member

    I tried to build Nobi's Horten Ho XIIIb with a balsa frame, but the balsa was too thick and didn't fit well. I plan to try again on day, though.

    Horten Ho XIIIb
  4. Darwin

    Darwin Member

    Seems to me that, if one is going to go to that much trouble, one might as well hang an elecric motor on it and do a little freeflighting. The combination of the balsa frame and card will probably be a bit heavy for rubber power.
  5. Gil

    Gil Active Member

    A Pleasure...,


    It is a pleasure to have you review your building method and techniques here. I have looked at your work on the Euro sites and have marveled at the "Look" that you are able to achieve.

    Bon Travail!,

  6. scon10

    scon10 Member

    I have some pictures for the interested reader on setting up the main construction and how to outline the panels of the model, so it would resemble the metal sheets on the real aircraft. The basic construction is straightforward, as you can see in the pictures, a central side-view bulkhead and crossection bulkheads glued perpendicular onto that. The bulkheads in the cilindrical part were glued at an interval of around 4,3 cm which is every two windows, and in the curved sections at the nose and tail more bulkheads which were roughly intrapolated and then sanded into shape.

    When that is in place, I marked the position of the windows and held a longeron, a wooden strip of 2x2 mm square, a few mm's below and above the window line and marked its postion on each bulkhead. After removing these strips, I then formed square dents of 2x2 mm in the bulkheads at the marked place, see a picture where I show the process on a loose bulkhead.

    Next time some more on actually outlining the panels themselves.
    Best regards,

    Attached Files:

  7. dwight prater

    dwight prater New Member

    I Have Built Solid Balsa Models From Cardstock Kits. I Like This More Than The True Cardmodel. Requres Alot Of Carving And Nding, Painting, And Detailing, If You Are Interested Drop A Line. Dwight
  8. scon10

    scon10 Member

    Next step is the actual of creating the panels. It is a very precise and accurate task, which requires some feeling for the airplane shape you wish to cover. In general, the less curvature there is, the larger the panels can be, but I would recommend not larger than 2, 3 or 4 spaces between bulkheads. In the nose and towards the tail, panels should be bridging adjacent bulkheads and longerons. In order to make a level surface (i.e. no raised surfaces of bulkheads or longerons) I glue strips of thin cardboard in crosswise fashion over all bulkheads and longerons. Usually I cover a bulkhead all the way round, and fitting strips on the longerons in between. By sanding where necessary, I ensure a flat, or smooth surface.

    I then place a piece of transparant tracing paper on the bulkheads and longeron on which the panel should be attached and trace an outline over the middles of the paper strips I mentioned in the last paragraph. Except for the very first one, all panels border on at least one other panel. Here comes the tricky bit: tracing the outline of a new panel must be absolute accurately positioned to the bordering panel because otherwise you will see gaps.

    The outline of the panel is then transfered to the skin, for which I use aluminium coloured or glossy white heavy paper. I buy this at the art shop ("lacquer paper").

    Regarding the order of the panels, I usually begin with the cockpit, and then onwards towards the nose and backwards to the tail of the fuselage.

    Normally you need to trim the panel to make it fit perfectly, which I will show next time.

    Best regards,

    Attached Files:

  9. scon10

    scon10 Member

    Next step in the process is fitting the panel. Every panel borders on 1 or more neighboring panels (except the very first one, of course), therefore getting an accurate fit is essential, to avoid misfits and gaps, which will ruin the effect.

    As an example, the pictures show the fitting of a panel directly behind the right side cockpit window.

    Please let me know, if there is an interest in this subject, and of course, if you have any questions, just ask.
    Best regards,

    Attached Files:

  10. scon10

    scon10 Member

    I have covered the framework of the fuselage with paperstrips in such a way, that the surface is smooth and in one plane, and so that the panels can be attached with ease onto the frame, see the various puictures.

    Now it is time to start building the panels with the windows of the DC-6B. I started with a copy from the print-out of the windows that were part of the side view of the fuselage. I printed these windows in the correct size (1:50) to the backside of aluminium-coloured cardboard. (I am going to use aluminium cardboard on the right side and white glossy cardboard on the leftside. That is because KLM had two colour schemes in the 1950's: white roof and aluminium at windows and vertical tailplane, but later in around 1954 colour liveries had white painted area's at the windows and the vertical tailplane. I want both colour schemes on the model)

    With a punch that I bought on the internet, and which has rotating punches as you push the top, giving very neat holes at various diameters, I punched out the 4 corners of each window outline using the 1,5 mm punch. Then the straight line connecting the corners were cut, and an open window results. From the plastic address window of a heavy duty envelope (I think from the income tax assessment..), I then cut the outlines of the windows in the exact shape as the outline in the aluminium cardboard, and with some plastic glue the pane was secured in the outline from the backside of the cardboard. In that way I made the whole length of the window panel.

    Next step is marking the correct position of the windows on the fuselage. The side view in the middle bulkhead gave a clue for this, I stuck a pin at the bottom line of the windows postion behind the side cockpit window and one at the end of the fuselage and stretched a thin thread between the pins, see pictures. The DC-6B window line at he underside of the windows runs at a level of around 0,9 of the pax window hight beneath the side cockpit window to the leading edge of the horizontal tailplane. Thie postion of the thread was marked on all bulkheads and longerons where posibble to give a guidance for the postion of the later window panels. I hope the pictures make this proces clear.

    Finally, I cut out the first panel of windows, starting the front, where the front cabin is located. The width of the panel is dictated by the two longerons running above and below the window line. As can be seen from the pictures, I haven't been too accurate, the longerons do not run exactly horizontal. However, that doesn't matter too much, since I am going to cut the windows in several smaller panels, containing two or four windows, depending on the actual position of the bulkheads, and because bulkheads are attached at double window intervals. It is essential, though, that the window panels top and lower sides run perfectly parallel and horizontal.

    Enjoy your weekend

    Attached Files:

  11. gippolot

    gippolot Member

    Very glad to see an update Scon10.

    Am enjoying the photos you post of this build.

    Andrew (or gippolot)
  12. scon10

    scon10 Member

    The time has come to prepare the first window panel for assembly onto the fuselage.

    First however, I want to detail the inside of the panel. Airliners of the fifties had little fabric curtains in homely colours fitting the windows. Those were the days, which I remember as a 10 year old, flying in one of KLM's DC 6B's to South America, and these real curtains were much finer than the ugly plastic sliding panels airliners now have... (By the way, the new Boeing 787 will have electically polarizing window panes, which can be darkened to non-transparant by the turn of knob. High tech, but still not very homely.)
    For making these curtains, I used the sort of tissue paper in which they wrap up china plates and cups in the department store. I have painted it with acrylic paint in beige, cut out small strips which are squeezed into a diabolo shape and glued to the inside of the window panel, at the window sides.

    Further, I modelled more or less a passenger head out of a small scrap of balsa, with some plastic putty, to make a rounded shape. A tiny triangular piece of paper is attached as a nose, and then I painted it with flesh colour, and brown hair, including an indication of eyes and mouth.
    Since the fuselage will be dark inside after finishing the fuselage, there is no need for too much detail, you will barely see the little head. It just gives a lively effect if you see a hint of passenger faces behind the windows.

    I fixed the figure to a bulkhead inside the fuselage and finally glued the window panel onto the fuselage.

    See the pictures, which also includes an general overview with the framework of the wings and horizontal tailplane. Just to get a feeling of how the KLM livery will look like when I make the decals at the final stage, I drew the KLM stripes in a photo painting programme, so that picture is a fake of course.

    Now will come a long period of drafting panels, fitting them in place and assembling the fuselage. In between, I will probably start on the wings and engines, which I will be happy to show.

    I wish you all a merry christmas and a happy new year


    Attached Files:

  13. scon10

    scon10 Member

    Time for an update.
    I've got pictures for you of starting to panel the wing and test build an engine, to see how it will fit.
    First, I want to keep the wing detachable from the fuselage, therefore the skin of the outer wing and the center wing need to be exactly matching and be in the same plane. To reach that, I put the wing in place, outlined a connecting paper strip over both wing root ribs , and after a good dry fit, glued that in place. When dry, I slit a razor knife between the two root ribs right through the connecting strip and ended up with a seperate wing and center wing with an accurate strip to carry the skin panels, see pictures.

    Then I startted to cover the wing with silver card, starting at the leading edge. I cut a long part of the leading edge, and cut that in three pieces, so that you would see panel lines and yet the whole would form a straight edge. See pictures.

    Next will come an engine test build from a 1956 card model of the DC-6B, to see, if I could use that.
    See you next time.

    Attached Files:

  14. scon10

    scon10 Member

    I am building the engines from a copy of a card model of the KLM Douglas DC-6B, published in I think 1954 by EMSCO in The Netherlands. The original scale is 1:66 2/3, which I scaled up with 130% to get a scale of 1:50. The original model has yellowed a bit with age, so the colours need to be repainted. also, the silver comes up as gray of course in a photocopy, so that also needs to be painted.

    The model itself seems fairly accurate, but I noticed that the underside of the inside engine nacelle did not have the bulge covering the main wheels when retracted, so I modified this part slightly, by extending the cutting line to the outside and making two v-shaped slits, After closing the slits with small strips of paper, and burnishing the the edges, it gave a nice rounded bulge. The other sections came together very well, the fit is most accurate, so I will use this model for the real thing. As can be seen from the pictures, I also burnished the small strip forming the inlet of the engine cowling and the cowling itself, so that it will not show an angular shape but becomes nice and streamlined, see pictures.

    The propeller in the model is just two flat halves glued together, so I put some volume there. I filled one half with heavy card, shaped a sharp wedge at the trailing edge and geve a correct twist of the blades.

    3 strips of thin paper rolled around the foot of the blades form the blade pitch housing at the propeller hub, see pictures.

    Next update will deal with the air intakes for the carburettor on top and the oil cooler at the underside of the nacelle and how I modified them to give better shape.
    Till the next time.

    Attached Files:

  15. scon10

    scon10 Member

    Just a few pictures of the engine and the air intakes.
    As you can see in the card model, the air intakes for carburetor and oil cooling are not very detailed or even well shaped, so I modified them.

    To start with, I added a "chin" underneath the air opening, by extending two lips under the air opening. I rounded these and closed them underneath, see pictures. Again, I made two narrow v-shaped slits halfway the airintake, so that they would become a bit more curved. The front side profile of the intake should run more or less parallell to the horizontal line of the engine centersection.

    Till the next time.

    Attached Files:

  16. scon10

    scon10 Member

    Hi All,
    Just a few pictures to show the progress on the DC-6B. Fuselage and wings are now fully covered with aluminium or white panels, and it is time to prepare the decals, that I am going to use to apply the KLM livery.

    I have drafted the blue cheatlines under and above the cabin windows, the various logo's and registration markings in Paint Shop Pro, printed them on normal white paper, and glued them temporarly with photo glue (a rubber detacheable glue) to the fuselage to check their size, see pictures. It starts to look like a 1950's airliner...

    I am not sure of the correct colour of the KLM blue of the period, I used the RGB code 24-77-116, but i anybody has a better suggestion, I'll look forward to that.


    Attached Files:

  17. Rick Thomson

    Rick Thomson Member

    Very impressive.
  18. 727engineer

    727engineer New Member

    That is outstanding, Inspiration enough to have another go at the Lufthansa 727, But I'll have to order another, the last was a catastrophic failure.
  19. scon10

    scon10 Member

    I have finished the DC-6B in this technique of silver paper panels on a frame of balsa. It seems to give a fairly technical character to a model of this scale ( 1:50 ) so here are a few pictures to show that. I still need to correct colours and brightness on some, and in a next thread I'll let you see, how you can have fun with models by showing you, what a passenger in the fifties would see from the cabin looking outside at the wing and engines, while another DC-6 or Super Constellation flies past...

    Attached Files:

  20. bfam4t6

    bfam4t6 Member

    Very very cool!!

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