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a D out of a G.... HK's B-17 conversion


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  • 3 weeks later...

Thanks for your kind words Cees!


Since my last update I've been looking again and again at the size/shape of the whole front end, pretty much right back to where the wing root meets the fuselage as I'm still of the opinion I haven't quite nailed the look I'd challenged myself to capture with this build.


As you may recall, I'd drawn up the original nose and rear fuselage conversion parts in Rhino3D and printed them. By a stroke of luck, I came into possession at this time of an excellent dimensioned side view drawing of the D model which I believe is actually an official Boeing drawing! A nice feature of the Rhino program is that you can import a background image into each particular drawing plane, scale it and then "build" your new model off it. I'd never done it before but it seemed like an option.


So the decision was quite easy; import/scale the photo, draw/print an entire new forward fuselage, graft the new one onto where the old one used to be, providing of course it looked better than what I actually had :)


Anyway, we all come for the photos, so here you go....




The drawings are now imported, scaled and ready to begin...




Pretty much built up in the same way you would if you were using traditional scratch building techniques, but a lot faster :)








I decided to see if I could get away with inserting the windows now and hope for the best in the print....












And into reality!










Yes the print quality is not perfect, but I'm only after the overall shape, the detailing and cleaning up will happen later.


I'm about to remove the left hand side of the existing fuselage to graft the new one on, some comparative photos to follow soon, stay tuned! :)



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Why Mike, you are still here to enjoy it!

Craig, fantastic how you use modern technology to reconstruct the ole' D. Your persistance is remarkable.

Slowly but surely the original HK parts decrease in number.

Would it have been an option to completely replace the entire fuselage when you started at first?


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Thanks Mike! Never too late you know :) 


Cheers Cees, looking at it now you would certainly think that it would have been easier to just do a whole new fuselage from scratch. :)


When I started out I thought it might have been a relatively straight forward process, but it has become bigger and bigger. I didn't have access to the drawings I do now, so when I did come across them it pretty much sealed the deal for me. The original plan is still in there, in that the whole concept was to pretty much leave the very centre section alone so it would provide structural strength and perfect mating for the wings (which, touch wood, I hopefully won't have to change too much). 


3D printed parts are not as strong as IM plastic, so there is always that factor to keep in mind. In using a blend of the two, there was always going to be a bit of a compromise on "total" accuracy, but I doubt I could have achieved much better from scratch too. 


In any case, this project has been a great learning tool into what can and can't be achieved with this new technology. As I have said, it is a tool to assist, but it is not the only way forward. There are many places where traditional techniques may have yielded better results, but I'm trying to document the potential here, oh, and hopefully have a nice model at the end of it. That would be a bonus! :)


One of my future projects is a 1/32 H-21 "flying banana." This will be entirely from scratch, so it will be interesting to see if I can build on what I have done here. It certainly opens up the flood gates to make your dreams a reality, but as always we are constrained by the information we have at hand.


Given the way I have done this project, if I were to do a York it would probably be along the same sort of path, although the fuselage would have to be entirely done from nothing. I do feel confident now that I could probably just start that one with a set of IM wings and go from there, but that's for another day! :)


Wow, rambled on a bit there didn't I?





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Keep rambling as long as it helps you to keep the progress up. The most important thing would be to have the centre fuselage intact for strenght and keeping the wings on. But you have thought about that already (was thinking about the Koster 1/48 Privateer conversion).


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  • 2 weeks later...
  • 2 weeks later...

Well Bill ask and you shall receive.... ;)


The first step was grafting the new forward fuselage back onto what was left of the HK fuselage. (I'm still calling this a conversion, not a scratch build!)




Here's a comparison between the two. You can see some small but important dimension changes, including....




The all important bulkhead #3 location. Despite all the effort I put into the cockpit earlier on, I feel the best way forward in light of the new information I have, is to rebuild this whole area from scratch. Did I mention I love a challenge? :)


Here, you can also see how wrong I had the windows. This was a result of trying to make the original kit fit with what I was trying to do. In the end, I had to go back much further aft to correct the shape errors, but this has definitely been worthwhile.






Scary stuff!






I like what brass could provide in terms of "sharpness," so I redid the window frames to the correct size. I think this is MUCH better....






I then drew up the nose cone piece as a solid shape and printed it out to see how close I got to the right profile.




Once I was happy with that, I split the drawing up on the computer into the 11 segments of the nose frame. This would then act as a master for all the shapes of the individual pieces I would need to be made from brass.




A quick comparison between the HK and my part....








Extremely rough at the moment, but over it's looking a lot better. I'm very glad I decided to have another go at the forward fuselage. I think it would have forever bothered me if I didn't!






Thoughts, opinions or comments are always welcome :)



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Not much to offer other than, WOW!  Just fascinating to follow along with!


Thanks Mike! Glad you're enjoying the show :)


This is about as hardcore as it gets, just plain amazing  :respect:


Did I mention HK are releasing a 'D' next month?


.....only joking ;)


Lol! I would truely not be surprised James. I'd be happy to see more D's getting built. This one has been a slog, but heaps of fun :)


Truly amazing work....


Thank you Sir! I'm glad you approve :)



You have nailed the character of the nose allright.



Thanks very much Cees! I certainly feel the whole redesign was worth it. And comments like that only encourage me to go and hack more plastic ;) 


I want this fort to be as close to capturing the lines of the real thing as possible, so it doesn't matter how long I take, I just want it to be the best I can possibly do.


I've spent the weekend re-doing the whole rear fuselage, based on the much more accurate drawing that I redesigned the nose with. It's printing section by section now, so hopefully soon we will be able to see a companion between old and new :)


Can't wait for that E/F version to be released :)



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That Rhino program looks pretty cool to work with.

I use Cinema4D but still need a couple of lessons to get to your level..

Great work.


Hi Jeroen, yeah I've really come to like Rhino, but I guess that's just because I'm used to it now. I've just recently found a few more features that are really handy, and have made my life much easier than the first time around. Stay tuned to see what I mean. I've never heard of Cinema4D. Is it a CAD program too? Are you using it to design 3D printed parts?


Holy moly lovin this build.... got a little burnt out after doing 3 forts in a row....the last one really done my but in...all commission builds and could,not face building my own....now the E/F on it's way....HELP


Thanks mate! Wow! 3? I feel your pain man. Have you got any photos of them? I'm glad you're enjoying the build. Been a lot of CAD work on the rear fuselage over the last two weekends and some printer issues, but there should be some progress to report soon :)



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So here's what I've been up to smile.png


I've been plugging away at re-drawing the rear fuselage on Rhino. Why did I do that? A few reasons actually.


Firstly, I got some better, more accurate drawings which gave better dimensional accuracy. What I had was pretty close, but seeing as I just did the front, why not make the back accurate too!


Secondly, the first time I did the rear fuse I lost most of the original drawings, so I unless I went the old-school, laborious way to find the correct contours for making the bulkheads, drawing them afresh seemed an easier way to get accurate contours.


Thirdly, in keeping with above, I figured I could also use the power of Rhino to work out the profile for the longerons and stringers and then print new templates to make them in brass or plastic. It worked well for the nose, no reason it shouldn't work here right?




The above is a screen shot of how I made templates for the bulkhead and the stringer profiles. Yes, the stringers wouldn't be that big, but they needed to be rigid enough to survive the printing process and I only needed the outer edge accurate.


So after an entire weekend's worth of puddling around to get the shape right, then split the rear fuse into sections small enough to be printed, one would have thought the physical printing would be a breeze right?


Very, very wrong.


In the fickle world of 3D printing, there are many many variables that can stuff up your print. For a start, your drawing can look like a technical master piece, but if the driver program for the printer doesn't like what it sees when you import it, you may be doomed to failure. The even better part is, it won't tell you what part of the drawing it doesn't like, so then you have to go back and try and work it out for yourself.  BANGHEAD2.jpg


The printer itself is not free from issues either. Even if you take a perfect drawing, mirror copy it and print both at the same time, they may come out looking very different.




Have a look at the join for the horizontal stabiliser. Same drawing, cannot explain why one printed okay and the other didn't. Luckily I can fix that.


To add to that, lately for some reason and more often than not, the printer can just stop feeding plastic about half way through your print. The printer doesn't know this has happened and the machine doesn't have a pause feature, so even if you happen to see it there's often very little you can do except start again. This is especially awesome when you are about 4 hours in to a 7 hour print. frantic.gif


In the end, a couple of the sections took four or five tries to get what you see below. Yes it's rough, but it's a solid base and shape, and that's all I need, so I rolled with them.




Just for amusement's sake, this is a photo of the extruder head on the printer. This eventually gets covered in molten plastic, which will semi harden during the print. If enough plastic builds up on the head, it can contact the part being printed, which can either dislodge itself from the base (ruined part - start again) or dislodge the entire extruder head (ruined part - recalibrate and start again!)




So there you go folks, even though 3D printing can produce some stunning results and slash the time taken when compared to traditional methods, it is far from trouble free. 


I wanted to show this to highlight the "other side" of using new technology for those who may think of it as a relatively straight forward process smile.png Having said that, when it works, it works a treat!


Oh and lastly, here's the new fuselage compared to the existing one. Pretty close, but you can see some dimensional changes. Still glad I did it smile.png





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