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  #11  
Old 05-18-2020, 05:35 AM
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Robotaleem Robotaleem is offline
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Quote:
Originally Posted by Sabedoria View Post
Share with us this 787 KLM in Jesus name
Wouldn't this be at least the second model you've asked for in Jesus' name?
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"The best landings are the ones you cannot walk away from" - David Windestål
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  #12  
Old 05-18-2020, 05:55 AM
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papermodelfan papermodelfan is offline
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About the varnish - when do you apply it? I'm thinking not after cutting out and glazing the windows, or the clear plastic might fog, and not before rolling the piece into a cylinder, or the varnish wmight crack. I must be missing something.
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  #13  
Old 05-18-2020, 06:22 AM
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I apply the varnish after the fuselage or the whole model is completed. You can't apply it on unassembled parts, for as you say, the surface will probably break up. I don't know for sure, I've never tried it.
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  #14  
Old 05-18-2020, 06:37 AM
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After the fairing for the main gear and the airco packs is installed, I marked two places where I want to put the axilliary spars in the fuselage for the wings to attach to. I will make the wings seperately, that is safer in order not to ruin the fuselage if anything goes wrong.
In the meantime, I drew the spars on 1 mm cardboard, front and aft with the curvature that is based on the first picture in the previous post with a part of the auxilliary spar in the fuselage, see pic 1.
These fuselage spars can be short, I only need them to firmly attach the completed wings to the fuselage, see pics 2,3 and 4.
In pic 2, I arranged the wing in place and started to think, how to construct the wing skins on a curved surface. You all know, that paper, unlike metal, cannot readily be formed in two dimensions. Next time more.
Attached Thumbnails
Boeing 787 flex wing in flight, an attempt-img_0027.jpg   Boeing 787 flex wing in flight, an attempt-img_0028.jpg   Boeing 787 flex wing in flight, an attempt-img_0029.jpg   Boeing 787 flex wing in flight, an attempt-img_0030.jpg  
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  #15  
Old 05-18-2020, 09:52 AM
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dhanners dhanners is offline
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Maybe I'm over-thinking it (and maybe it won't be an issue in this scale) but given the nature of paper, how will you get the wing's underside to lengthen and the upper surface to compress? The kit is designed with relatively straight wings, and getting them to curve to that extreme seems like a difficult task without creasing.
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  #16  
Old 05-18-2020, 10:30 AM
ser400 ser400 is offline
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Just so you know, the first diagram showing the wing in the extreme curved shape is not anything that you would see under "normal" flight conditions. I'm pretty sure that diagram represents the wing under "test" conditions, probably at Ultimate load. Ultimate load is a test condition used to certify the aircraft with the regulatory agencies of various countries. It represents a severe loading that the aircraft may encounter once in its lifetime. Look at photos of the 787 in-flight and you will not see the wing deformed even to half of what is shown in the diagram.
Not being critical, just wanting to inform. I worked for 37 years in the test dept at DeHavilland/Boeing/Bombardier (the various owners while I was employed there).
Hope this was informative.
Bruno
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  #17  
Old 05-18-2020, 12:06 PM
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dhanners dhanners is offline
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Found these online. Does seem like the flex can be fairly significant.
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Boeing 787 flex wing in flight, an attempt-img_9460.jpg   Boeing 787 flex wing in flight, an attempt-img_9461.jpg   Boeing 787 flex wing in flight, an attempt-img_9462.jpg  
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  #18  
Old 05-18-2020, 01:32 PM
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The first picture in Dhanners post says it all. Boeing went to 150% load which results in a tip rise of 26 feet. I am trying building the 1 g flex, which flexes up to 10 feet above neutral. Remember, composite material is not comparable to aluminium alloys.
Ultimate load (to which Boeing did not go to) is significantly more flexed than 150% load as compared to normal flight. Ser 400 knows how dangerous such a test can be. I have no experience in ultimate load composite wing testing, only aluminium alloys, but I imagine the explosion of a composite structure can be just as, if not more, dangerous.

Another give-away is that in flight , viewed from the side, you can see the other wing above the top of the fuselage. When on the ground, you do not see the other wing.
Reagarding Dh. other remark on compressing the upper side and stretching the underside of the wing, I solved that by building first the underside, and then the uper side. These skins neede to be adapted, as you already expected. In next posts I'll show how I did this. Others may have found other solutions, and I'll be most interested to hear about that.
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  #19  
Old 05-18-2020, 02:02 PM
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Tigris Tigris is offline
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Very interesting! Good job and good luck building!
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  #20  
Old 05-20-2020, 08:03 AM
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The front and aft spars with their curve now look like pic 1, which also includes the planform of the wings, cut from 1 mm cardboard.
I am going to split these spars in a top and bottom part, which I will then glue onto the planform of the wing, see pic 2. This is to be able to put the wing profiles in place to support the wing skins. The curved wings look like this from the front, see pic 3.
I will attach the wings to the sub spars in the fuselage by making splits, and shove the wing in place, see pic 4. When this is done, I can now start putting all the wing profiles in place, see pic 5.
Attached Thumbnails
Boeing 787 flex wing in flight, an attempt-img_0041.jpg   Boeing 787 flex wing in flight, an attempt-img_0042.jpg   Boeing 787 flex wing in flight, an attempt-img_0034.jpg   Boeing 787 flex wing in flight, an attempt-img_0043.jpg   Boeing 787 flex wing in flight, an attempt-img_0044.jpg  

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