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Boeing 747SP - NASA/DLR SOFIA - Welsh Models 1/144


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I've got a few entries in this GB in mind and haven't entirely decided on the others yet, but the first one is definitely going to be the Welsh Models 1/144 vacform Boeing 747SP converted to the NASA/DLR telescope-carrying aircraft N747NA. I'll post a pic of the kit later, but here's the 1/1 version in flight:

spacer.png

 

I've been doing some CAD work on the telescope and fairing:

telescope

and done a test print of the parts:

SOFIA telescope parts

 

This was my first attempt at a print with my Photon Mono printer. Some of the parts came out fine, some of them will need to be printed again with the supports in a different place or in a different orientation, and a few of them (particularly the rear parts of the fairings) were too thin and didn't come out well, so will need to be redesigned (but I have a plan for that). Also needs to be test-fitted to the fuselage so I might need to tweak the design for a better fit.

 

It's going to be displayed in flight (probably) as the door to the telescope cavity wouldn't usually be open on the ground. I'm currently on the lookout for a suitable base for a stand.

 

V1 decals produces some good-looking laser-printed decals for N747NA - I've got 2 copies just in case (if you want two copies of a sheet in case you need spares they sell the second one half price).

 

Can't wait to get going. Might start cutting out the vacform parts a bit early - it'll be well below 25% when we start.

 

thanks for looking

Julian

 

 

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This is very cool project--lots of points for the coolness factor of the subject and the design and manufacturing of your additions! :popcorn:

 

AFAIK, the program is run out of NASA Ames at Moffett Field while the aircraft is based at NASA Armstrong in Palmdale. 

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5 hours ago, dnl42 said:

This is very cool project--lots of points for the coolness factor of the subject and the design and manufacturing of your additions! :popcorn:

 

AFAIK, the program is run out of NASA Ames at Moffett Field while the aircraft is based at NASA Armstrong in Palmdale. 

Thanks. Yes it’s managed by Ames and operated by Armstrong. Also usually spends a couple of months in Christchurch every year (maybe I should have built it in the Anzac GB!) and seems to visit Hamburg from time to time.

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A really cool project!👍

 

I believe she is in Europe right now until the end of March.

I've been looking at Flightradar24, she seems to be flying out of Cologne, mostly taking off after sunset and returning in the early hours of the morning. 

So, even if there were no travel restrictions due to Covid, I'd have to be really lucky to see her fly.

 

Cheers, Stefan.

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INSANE! I am totally following this. If someone would make it in injection (or resin I guess) in 1/200 I would pay top dollar for it. I sometimes imagine about how if I came into 100 million dollars one of the cool things I would do (after loads of good works, of course) is to start my own line of 1/200 kits to go with the Hasegawa ones I have. The 747SP and this one in particular are both on the top of that imaginary product launch schedule 🤣

 

Looking forward to this!

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12 minutes ago, bianfuxia said:

INSANE! I am totally following this. If someone would make it in injection (or resin I guess) in 1/200 I would pay top dollar for it. I sometimes imagine about how if I came into 100 million dollars one of the cool things I would do (after loads of good works, of course) is to start my own line of 1/200 kits to go with the Hasegawa ones I have. The 747SP and this one in particular are both on the top of that imaginary product launch schedule 🤣

 

Looking forward to this!


Pretty sure I saw a downloadable stl file on the NASA website. Not sure what scale it was (it was smaller than 1/144) but you could download it and print it.

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Time to get started, not that I've done much so far, just got all the parts off the backing sheet. I'll be getting to work with the sanding blocks tomorrow. 

 

All the airframe parts are vacformed and the engines and undercarriage are resin. Here's what comes in the box:

Welsh Models 747SP

 

There's also a nice looking decal sheet - I think this one was produced by TwoSix - for a PanAm aircraft, not that I'll be using it (maybe I'll save it for an Eastern Express kit). I suppose it's fitting that it's a PanAm boxing since that's where N747NA started its career.

 

thanks for looking

Julian

 

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First test-fit of the fuselage and the telescope bits:

 

1:144 747SP WIP

 

1:144 747SP WIP 2

 

Fuselage looks like it's going to go together quite nicely. The telescope bits fit quite well as well - they're slightly wonky in these photos because the fuselage cut-out needed to be expanded slightly - but looks like it's going to work.

 

I think the next steps will be to get the wings assembled and test-fitted to the fuselage, then get everything properly cleaned up before I start fitting the telescope and assembling the fuselage. I'm going to need to print some of the telescope bits again as well.

 

thanks for looking

Julian

 

 

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:analintruder: Interesting project you've got here Julian. 

 

I'll take a seat at the back with my notebook in hand and enjoy the rest of the show if I may. 

/Bosse :popcorn::beer:

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  • 2 months later...
21 hours ago, Michael Morris said:

How is the SOFIA build going?  I'd love to find out more about this really interesting project.

It's not happening at the moment. Combination of busy work life and some difficult family issues mean I don't have the mental energy for it - instead I'm doing quite a lot of simpler modelling which is proving to be quite therapeutic and right for the circumstances. I'll come back to this build but it's the right build at the wrong time.

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  • 3 weeks later...

Zebra,

I just joined Britmodeller to comment on your SOFIA model.

I occasionally look around for anything related to the SOFIA program and found your post here.

I have a personal interest as I was the lead structural design engineer for the Upper Rigid Door taking it from loft-lines to the solid model used to make the production drawings.

I left the program just as the drafter was starting to work on the drawings. I happened to go back for a visit when they had a roll-out ceremony when the door assembly was completed. It was sitting on the assembly tool and I crawled under and took detail photos. Kind of a walk-around of the door.

I still have a copy of the cad file with some of the 747SP fuselage dimensions near the door.

Anyway, I just wanted to say that I am very impressed by your 3d print model. It looks very much like the original.

I never did get a copy of the final drawings. I would like to have studied them but oh-well.

 

Some interesting notes. The 747 fuselage tapers from constant section to the tail, however the taper starts at different stations.

The bottom of the fuselage has to be shaped to clear the ground for aircraft rotation. The sides of the fuselage maintain full width a little further aft because that allows for about two more rows of seats. The top of the fuselage starts to taper about in the middle of the door. So the front of the door is integrated with the round upper shell of the fuselage but the back of the door integrates with a fuselage that has a taper that is continuously changing.

That is part of the reason why the fairing aft of the door has that step in it which you correctly modeled.

 

When they did the fight test the goal was to have access to the full flight envelope. One of the last of the flight test parameters was a high speed dive. So yes, this door has been exposed to Mach 0.9 and passed the test.

 

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You can't beat first hand information!  Welcome @JBinSV, I suspect that if you wandered into the Real Space and Sci-Fi section, you'd be cyber mobbed by folks wanting your expertise. It truly is amazing at what the collective knowledge on this forum is (personally I add very little)

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This is a NASA image taken when the door was being installed. You may have seen this online. The door has a partial inner skin which makes a box frame around the perimeter.

door 101

 

 

Views of the door on the assembly fixture. This is in the hanger at NASA Ames where the ER-2 aircraft used to operate.

 

door_001

 

jbaloun

door_002

 

 

 

door_003

 

 

The forward end of the door and the extra structure to withstand the stress and strain around the opening.

 

ext_022

 

 

The aft end of the door.

 

ext_023

 

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