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1:9 Scale B-17G - 'Sweet Pea'

wilmracer

I build things that fly (sometimes)
Mentor
One down twelve to go:p
Yup! Only 4 of them get the full rig for a "flexible" mount. The turret mounted ones where the gun is visible will get the gun without the mount/sight (I'll do the correct sight for those) and then the others will just get the barrels. They didn't call it a fortress for nothing! LOADS of firepower.

I'm not certain if I'll do the radio room gun deployed or not. That large opening on top would be tough to build out convincingly while hiding the internal structure of the model. But yeah, 13 guns... that is a LOT.
 
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JTarmstr

Well-known member
Test print for the pilot seat shows my eyes are no good at measuring. They weren't sitting in Lay-Z-Boys in there. I'll make some adjustments but the overall design should be OK. The figure is 8" tall, a scale 6ft tall pilot.
One scale detail, most of the time when they were flying in combat, they were either hiding behind the instrument panel or putting out fires.
 

SlingShot

Maneuvering With Purpose
Yup! the barrels. They didn't call it a fortress for nothing! LOADS of firepower.

But yeah, 13 guns... that is a LOT.
Teachable moment: A lot of guns, but still not enough.

It was originally thought, that the
combined interlocking firepower of large flights of B-17's, would be so formidable, that fighter escort would be rendered unnecessary. They were wrong.

Fortunately, for aircraft aficionados such as ourselves, long range fighter escort was developed, and we got the P-51 Mustang.
 

JTarmstr

Well-known member
Teachable moment: A lot of guns, but still not enough.

It was originally thought, that the
combined interlocking firepower of large flights of B-17's, would be so formidable, that fighter escort would be rendered unnecessary. They were wrong.

Fortunately, for aircraft aficionados such as ourselves, long range fighter escort was developed, and we got the P-51 Mustang.
I have been reading a oral history of the 8th air force, it turns out that the Germans actually calculated a attack angle where the B-17s could only get a few guns to bear. This angle was generally head on and 15 degrees above. The B-17G remedied this angle with a nose turret but by then the Germans had developed rockets.
 

wilmracer

I build things that fly (sometimes)
Mentor
I feel like I've been furniture shopping with the wife... I'm getting sick of looking at chairs and they all look the same now ;-)

Actually Mk3 (one on the far right) is pretty close. It is a bit tall on purpose so I can trim the legs to the right length, and so I can recess them into the cockpit floor for a stronger bond so they don't work loose after a few of my "smooth" landings.

More 20 degree days in the forecast so probably more CAD for a few days. Not much got done over the weekend thanks to problems at work :-(
 

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wilmracer

I build things that fly (sometimes)
Mentor
So a little progress was made yesterday when the shop warmed up enough to be out there. I got the servo tray built and installed for the tailwheel retract and steering servos. These are as far forward as I can put them without them interfering in the wing attachment area. I hooked up the pushrod for the retract and will be hooking up the pull/pull setup for steering tonight or tomorrow.

Something else cool did happen... a maker page picked up the build and did an unexpected story about the project, and as a result the project got a few thousand views yesterday and gained a lot of followers on YouTube.

https://hackaday.com/2019/02/05/the-design-and-construction-of-a-tribute-to-a-bomber-pilot/
 

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wilmracer

I build things that fly (sometimes)
Mentor
Got the pull/pull cables and the gear pushrod hooked up. I'll do some tweaking and testing before closing up the fuselage. Cotter pins were used on both ends of the kevlar line. A longer pin is used on the servo side for adjustment and a short pin is used on the gear end to provide a solid but removable link. I stole the cotter pin idea from @willsonman and it works great!

I'm considering what, if anything, I'll do with the lines when they go slack. There isn't TOO much slack in them when the gear is retracted and they just lay on the floor on the inside right now. I thought about a working up a spring to keep them tight but I'm not sure if it will be necessary. Thoughts?
 

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JTarmstr

Well-known member
I'm considering what, if anything, I'll do with the lines when they go slack. There isn't TOO much slack in them when the gear is retracted and they just lay on the floor on the inside right now. I thought about a working up a spring to keep them tight but I'm not sure if it will be necessary. Thoughts?
If its not to much slack, I would use a low tension spring mounted on one of the bulkheads that pulls the string closer to the fuselage, keeping the slack off when its retracted.

Btw finished the book I was reading, no mention of your grandfather or his plane, but its crazy what the pilots and crews went through on the missions, especially during 1942-3.
 

rockyboy

Skill Collector
Mentor
The cotter pins are brilliant!

To keep a little tension in the line, you could tie in a rubber band so it takes up the slack too. Might be easier than finding the right size spring.
 

wilmracer

I build things that fly (sometimes)
Mentor
I'm thinking over options to contain the pull-pull cables. I'm also debating a false "floor" in the rear, probably from 2mm foam or maybe 1/64th ply (although that would be a pricey floor). Perhaps I'll just put the false floor in the areas that have the large windows for the waist gunners. The floor would be much too high to be scale, but it could help hide the controls when folks glance through the windows to the gunner positions. In the end I'll have to make some scale sacrifices in this area but I definitely don't want the visible interior behind the guns to be white and pink :)

So yesterday I went in the shop planning to make up a paper tube to run the wiring to the tail. Then I remembered that we got new bulbs for the aquarium this week, and the 48" bulbs had a paper sleeve over them. I mulled it over a bit but decided to go with it! The 48" box tube weighed in at .3oz and I only needed about 30" of it, so the weight is negligible. I opted to install it buried into the upper portion of the formers. I looked at running it down the floor but decided I didn't want the cables taking a path where they could interfere with tailwheel retract and steering.

Getting close to ready to close up the fuse. Once she is closed up I'll need to install the horizontal stab before starting the balsa sheeting process.
 

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...I'm also debating a false "floor" in the rear, probably from 2mm foam or maybe 1/64th ply (although that would be a pricey floor). Perhaps I'll just put the false floor in the areas that have the large windows for the waist gunners. The floor would be much too high to be scale, but it could help hide the controls when folks glance through the windows to the gunner positions. In the end I'll have to make some scale sacrifices in this area but I definitely don't want the visible interior behind the guns to be white and pink :)...
Why not just use some sections of DTFB. Or am I missing something?
 

wilmracer

I build things that fly (sometimes)
Mentor
Why not just use some sections of DTFB. Or am I missing something?
Weight. All of this is aft of the CG and even with everything that gets installed on the other end of the CG I still need to keep the tail as light as possible. As this will be difficult to access after the model is closed up I don't want to use DTFB with paper installed. If it starts to delaminate it would be hard to swap out. I'll play around with options tonight. I need to do another deep cleaning in the shop before this weekend but I'd love to be closing her up by the end of the week
 

willsonman

Builder Extraordinare
Mentor
Perhaps you could consider foamboard but take that paper off and apply some glass with WBPU? the only other thing I would think of is "For Sale" sign plastic. Like a styrene or ABS sheet plastic. Not sure what the weight penalty would be but it's a thought.
 

rockyboy

Skill Collector
Mentor
What about manilla folder material or cardstock? I think that's lighter than bare DTFB, and it would take some paint better if you want to get fancy inside...

Or maybe just make little boxes out of cardstock, paint the inside, and stick them over the window holes? No need to floor the rest of the beastie!
 

SlingShot

Maneuvering With Purpose
What about manilla folder material or cardstock? I think that's lighter than bare DTFB, and it would take some paint better if you want to get fancy inside...

Or maybe just make little boxes out of cardstock, paint the inside, and stick them over the window holes? No need to floor the rest of the beastie!
Hmmm...I sort of had that idea also. You could print any kind of facade that you wanted.