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HK B-17...C 11/2 progress resumes!


brahman104

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19 hours ago, Captain Boogaloo said:

An awesome thread ( perfect for soaking up a bit isolation time!)- 67 pages of inspirational modelling that has become an odessey of new kit, problem solving and pattern making. Just wow. And you moved to a new country, to boot. Although if I'd had a Wocca  and a B17 crash site, I'd have been very tempted to test the heavy lift reputation of that beautiful helicopter...! 

Now just when are you going to sell a few of your hard won resin B17 noses?? Be a good way of clawing back a bit of the cost of those new toys, er I mean essential workshop tools! Keep plugging away, looking forward to seeing the next instalment!

 

Blue Skies !!

Captain Boogaloo

 

G'day mate, glad you're enjoying the (long) journey so far!

 

About the black cat B-17...... yes I really wish we could, seeing as it's slowly decaying sitting out there on a hillside. Unfortunately, PNG only sees things like that now as revenue earners, even though they do absolutely nothing to preserve them. In fact, there was quite a bit of angst at a local airfield we landed at not long after as they thought that's what we were there to do!

 

On the subject of selling resin nose corrections; it's something I'm still thinking over. As you'll see below it's not just as simple as filling up the vat, pressing print and all of a sudden you have ready made parts to drop fit onto the model. The way forward (eventually) would be to keep refining the shapes and then create masters to cast in normal resin, as the 3D prints can just be too unpredictable. Good for prototypes, but not production...... In any case, it will still be quite some time before I am ready to do that, especially considering what's going on in the world right now!

 

17 hours ago, TKB said:

Craig,

 

I can't add anything more to what everyone else has said about where you've brought this to!

 

It's sometning to look at the last two photos and see all that remains of the HK kit are the two Bulkhead #4 through #6 fuselage halves!

 

Terry

 

Thanks Terry, guess what? I was thinking about the outboard engine corrections last night and I think I have a new plan. More on that later, but you won't be surprised to hear it involves more removal of original kit parts! ;)

 

P2kfwjG.jpg

 

So after another 15 and a half hours, the right hand side came out. 

 

gzk6b15.jpg

 

As you can see, 3D printing (at least for an amateur like me) is still quite a hit and miss affair. I only drew one side in Rhino, then mirrored it, so theoretically they should print exactly the same right? Wrong. Even though I will still use this, the circled issues highlight exactly why this is not a straightforward process than I can make up sets to send to people at this point.

 

Anyway, I now have the two halves that I can work with I'll continue to refine (especially around the nose cone) to make sure they're the same, and start dealing with the fitment around the #3 bulkhead. :)

 

More to follow soon.....

 

Cheers,

 

Craig

 

 

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A bit more progress to show. I've had some solid bench time lately so I've been able to concentrate on getting things right, and trial a few other innovations as you'll see shortly.....

 

First of all, the cleanup on the nose continues. 

 

1of0Eqn.jpg

 

I'm taking my time to clean up as much as I can now with the two halves together, before they separate again and rejoin their respective fuselage sides. Getting the observer's top hatch to sit nicely has been quite time consuming, but definitely worth it to do now!

 

XSiBON1.jpg

 

I also added a bit of a styrene "shim" to the front to make the nose cone fit a little better.

 

And a good scene of carnage for you :)

 

reGoQTp.jpg

 

You'll recall my efforts to adjust the height of the outboard nacelle from a while ago....

 

7jw9eyO.jpg

 

While this approach had merit, I would still have to correct the profile for each side, and considering I have two other B-17 projects to do eventually, I wanted a more repeatable, predictable solution.....

 

A bit of a gamble, but I decided on a full remove and replace option. Hopefully, this would give me a much easier solution (as I would only have to draw one side, once). This turned out to really tax my brain, as working out a decent reference point, plus trying to make sure the kit's wing profiles were captured was some of the most challenging work I've done on this kit. Simple, easy to read drawings of the outboard nacelles are a little tricky to find, but I used my good old eyeball once again to make something that while maybe not 100% correct, still looked better than the kit option.....

 

It started with removing a big chunk of wing:

 

lD46orm.jpg

 

I used the kit's rivet lines and rear spar location as my datums for top and bottom (hopefully HK got them the same both sides!)

 

Wu2kizw.jpg

 

Once I had my hole, I then traced profiles of each face to be replicated....

 

Z7IgU4o.jpg

 

1fAyBom.jpg

 

After a lot of mental gymnastics in Rhino, I made a simple profile mockup to make sure I'd got things right....

 

vo3oJN2.jpg

 

2zQLZ84.jpg

 

Not completely refined or complete yet, but I can't believe I pretty much got it right! I've still got to add a lot of detail and then the final product will once again be in resin, but I feel it's a quantum leap forward in regards to my original approach....

 

K681aHM.jpg

 

MY7PNsr.jpg

 

I do apologise in that it is very difficult to portray in a photograph what it actually looks like in real life, but the important thing is that the "thrust line" of the engine is now lower than the leading edge of the wing, exactly as it should be.

 

In all, I only have to tweak the inside aft edge of the inboard profile just a little to get it to line up with the wing profile when viewed from the front... if that makes sense?

 

Anyway, this is a huge step forward once again, and I'm looking forward to showing you a finished nacelle printed in resin hopefully in the near future!

 

Cheers, Craig

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Back again,

 

I spent an entire day just drawing the aperture where the turbocharger lives under the nacelle, along with establishing a mounting "flange" to increase the strength of the join once the finished part is back in the wing.

 

Here's what I had to add. Looks pretty easy, but there's some very tricky curves and angles in there....

zZxz3td.jpg

 

Even though I was reasonably confident that I had nailed the dimensional stuff right, I still did a trial print before committing to resin, just to be sure....

 

EztKL7m.jpg

 

Looks pretty good to me! Of course there's heaps of other details that could be added to the drawing, but as I'm going to skin this with litho anyway there was kind of no point. There's also little air inlets and things around the cowl but I'm also keeping in generic enough to reuse on the E/F.

 

The resin print will go on tomorrow morning. Hopefully it goes according to plan!

 

Cheers,

 

Craig

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7 hours ago, brahman104 said:

Back again,

 

I spent an entire day just drawing the aperture where the turbocharger lives under the nacelle, along with establishing a mounting "flange" to increase the strength of the join once the finished part is back in the wing.

 

Here's what I had to add. Looks pretty easy, but there's some very tricky curves and angles in there....

zZxz3td.jpg

 

Even though I was reasonably confident that I had nailed the dimensional stuff right, I still did a trial print before committing to resin, just to be sure....

 

EztKL7m.jpg

 

Looks pretty good to me! Of course there's heaps of other details that could be added to the drawing, but as I'm going to skin this with litho anyway there was kind of no point. There's also little air inlets and things around the cowl but I'm also keeping in generic enough to reuse on the E/F.

 

The resin print will go on tomorrow morning. Hopefully it goes according to plan!

 

Cheers,

 

Craig

 

 

You sir, are a Rembrandt. A king among men. Very impressive stuff.

 

- Dennis S.

  Thornton, CO USA

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On 4/1/2020 at 4:04 AM, tomprobert said:

Impressive stuff - there won’t be much of the original HK plastic left at this rate!

 

I think you’d struggle to find a more accurate rendition of an early Fort anywhere - loving this. 
 

Tom

 

Thanks Tom! I reckon I should've just built a real one..... I'd probably finish it quicker! :rofl:

 

On 4/2/2020 at 10:01 AM, Gazzas said:

Love this build and the way you're going about it.

 

Thanks very much mate! I'm really enjoying it.

 

So, resin printing..... seems I've still got a lot to learn!!!

 

Having just moved, I didn't have a huge amount of resin, and I wasn't too sure how good the stuff I did have was. In any case, it seems that orientation and supports are even more important than with FDM printing. This is how my nacelle turned out....

 

Y4ADTH6.jpg

 

You can see a big line where for some reason it slipped or shifted during the print process, not terrible except for this.....

 

9Khlh2S.jpg

 

This is what happens when you don't pay enough attention to the orientation and supports........ I took me about an hour to remove to the point of what you see here, and going to take a whole heap more time to clean this up! 

 

Want to see it get worse? I knew I was pushing my luck, but I tried to quickly set up the other side to print. I think this was definitely a case of the resin being no good....

 

sjMOUZu.jpg

 

Exactly the same drawing, just mirrored...... As I said, this is entirely operator error. It does go to show you how finicky resin printing is!

 

Anyway there's more resin on the way now, so I'll have another go when it gets here. Luckily it's not going to hold up the build at this point.

 

On a positive note, I've been steadily grinding away and test fitting the nose halves to the fuselage. Looking good!!

 

HOBPVqt.jpg

 

t3qODFQ.jpg

 

91STPmI.jpg

 

OVQVfr1.jpg

 

In the last one you can see a significant "step" in the sides. I thought about trying to correct that but I think it will be easier and stronger in the long run to blend them later. There's definitely going to be some heavy filling and sanding once I permanently attach them, but that's life!

 

Here's what I've had to grind away so far on the inside.....

 

zKGzDmW.jpg?1

 

Z1jc3iY.jpg?1

 

I'm trying to get as much of the messy grinding and fitting work done prior to attaching the sides back on now, including painting. I'm even considering the cockpit/nose glass at this point as it might become too difficult to fit later!

 

Cheers,

 

Craig

 

 

 

 

Edited by brahman104
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20 hours ago, shark64 said:

ouch

 

Hi Oliver, yeah I'm pretty sure it was me at fault. All part of the journey! :)

 

9 hours ago, Shawn M said:

keep at it, the results WILL be worth it

 

Thanks Shawn. Yeah I'm not that worried about it. I have more resin coming, life is good! Lots of other little bits and pieces to keep me going in the meantime ;)

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"But 3D printing is so easy, you just klick a button..." Yep, the REAL joy of 3D printing - things like that have happened to all of us! :) 

 

I would try to separate the foremost portion of the nacelle from the rest and to print the part flat on the printing surface, using the surface resulting from the cut as base. Supports have to be added for the wing leading edge of course. I think I have to read that twice to understand what I mean myself... anyway, I hope you understand what I mean. In my experience, 90 degrees prints work better on simple resin machines than inclined parts, at least for big prints. Make sure to perfectly mix the resin bfore you start the print. The temperature is a source for failed prints as well. 

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On 4/4/2020 at 12:28 PM, Anthony in NZ said:

Aside from the nacelle, the fuse looks AWESOME!

 

I think you have nailed the 'look/feel of the ole girl....nice one!

 

Thanks very much Anthony! I'm slowly working my way through your epic Mosquito build too; looks like we're both in a labour of love :)

 

9 hours ago, Starfighter said:

"But 3D printing is so easy, you just klick a button..." Yep, the REAL joy of 3D printing - things like that have happened to all of us! :) 

 

I would try to separate the foremost portion of the nacelle from the rest and to print the part flat on the printing surface, using the surface resulting from the cut as base. Supports have to be added for the wing leading edge of course. I think I have to read that twice to understand what I mean myself... anyway, I hope you understand what I mean. In my experience, 90 degrees prints work better on simple resin machines than inclined parts, at least for big prints. Make sure to perfectly mix the resin bfore you start the print. The temperature is a source for failed prints as well. 

 

Hi Ben, thank you very much for the tips. What you're saying makes very good sense and I'm keen to try it. Knowing your experience in all things 3D printed I'm inclined to follow your advice over a lot of the other weird and wonderful "how to print parts perfect every time" tutorials I've seen lately!

 

9 hours ago, Starfighter said:

Oh, by the way - absolutely stunning work so far - I am a huge fan of the efort and determination you are putting into this project! 

 

Thanks again Ben! I likewise am a huge fan of your builds. There's something very satisfying about building something unique, and you Sir, are the master at that!

 

While the print work on the nacelles is annoying, it's not slowing down the rest of the build. I'm currently installing the windows in the nose and cockpit, so I can finish as much of the interior walls as possible prior to reattaching the sections to the rest of the fuselage.

 

0WMjrzF.jpg

 

swm9FHZ.jpg

 

All of the sections have been made using 1mm acrylic sheet. If there's one thing I feel I'm getting better at from this build is working with transparencies. Even though I didn't vac form these to conform with the fuselage contours, by having the 1mm thickness I was able to file them back to flush prior to polishing them. It takes a long time, but it's starting to look good. The only problem is that it's hard to photo once they're done as you can't see them ;)

 

On the inside of the cockpit I've thinned the window ledge out to make room for the sliding window track. Still some refining to do, but this should work okay. This piece, being thinner, will allow the window to be posed open.

 

oGBwNO8.jpg

 

In the meantime too I've been getting my machine tools set up and ready to have a go at the landing gear. The transport crates I made for the move are proving to be fantastic makeshift workbenches!

 

M1jKumL.jpg

 

And lastly, here's proof that NZ is taking this seriously.....

 

rHuziJQ.jpg

 

Cheers,

 

Craig

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