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


brahman104

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Craig,

Your "headliner" came out great! The fastener studs really look the part!

Everything in the nose back in its place! Sure doen't look like "recovery" work.

Must admit though, I do miss the look of  "your" original padded insulation and window frames! But as I'm always fond of saying "you're the one doing all the work!"

When you close her up, it will be a shame what is not readily still seen. It's there, we'll just have to look hard! Fortunately we have your "in progress" photos!

 

Nice lathe work on the bombardier's seat "barber's chair" pedestal base. It was a pretty bulky item and never quite understood it compared to other seats mountings. Perhaps it offered more "adjustabiity" to suit the individual bombardier as well as being more stable and less prone to vibration when he was using the bombsight? Think it was replace sometime during B-17E production, definately with the F. Most pictures I've seen of 8th Air Force E and F nose interiors, it appears the bombardier's seat was "tossed."

 

Terry

 

 

 

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  • 2 weeks later...

Thanks lads!

 

Well being back at work has sure slowed the progress again, but in the background there's been considerable discussion regarding another very important element to achieve the all important "look." B-17 cowlings are not as straightforward as one might initially think. Terry (TKB) has been doing a huge amount of research on my behalf and without going into it too much here, the shape differences we found meant that a redrawn cowl was necessary.

 

amZucbq.jpg

Here's a line up of the cowl options. From the left is my new one (just a rough print at this point), Eduard and lastly the HK version.

 

Also note that the C didn't have cowl flaps, so mine is the finished overall dimension, as opposed to the other two...

 

A substantial myth that needs to be busted right now is that when the F-G series went to the wide chord paddle props, the cowls were NOT reprofiled to suit. Front edge was simply moved rewards toward the engine. This is obvious when you overlay the two cowl profiles from the original factory drawings....

8Pernpv.jpg

VGC5XbN.jpg

tGPfXxn.png

 

What is also important, is that the very front of the reduction gear housing on the engine sits flush with the front of the cowl on the B-E, but protrudes ever so slightly on the F-G, as seen here:

gZ3GPV1.png

The B-E should look more like this:

Fjn27gC.jpg

 

This leads to another issue. If the eduard engine sits in the correct position relative to the cowl, the front of the engine protrudes too far. Check out the below pic:

uYyVNRJ.jpg

Even though this is the Eduard part, it's still too far out for an F-G. What does that mean? It means that I am seriously considering redoing the reduction gear housing on the front of the eduard engine. The more I look at it, the more it is the wrong shape.... It might only be a mm or so too long, but look what a rouge mm meant to the shape of the windscreen/cockpit area?

 

I think it's worth doing :)

 

Anyway, I have also done up a new tail wheel. The B-D's had a smaller (by 3 inch) diameter wheel, so I had a go in Rhino at a new one, massaging control points to attempt a little weight bulge in the bottom...

 

B7DYr2X.png

 

And in the flesh, so to speak...

PzKNGjw.jpg

cZZv1Vp.jpg

NV2jpoH.jpg

 

Not too bad! Onwards we go. Might have to get some "skinning" practice in for those cowls once they're done!

 

Cheers,

 

Craig

 

 

Edited by brahman104
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Hey Craig - love the gear and cowling work!!!  The changes these aircraft went though during their operational periods is so very interesting.  When I did my Mustang years ago I was just amazed at the changes.  The engineering teams must have never slept, not to mention the poor factory teams who had to manage the changes coming out of engineering.     

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  • 2 weeks later...
On 5/5/2020 at 11:40 AM, JayW said:

Hey Craig - love the gear and cowling work!!!  The changes these aircraft went though during their operational periods is so very interesting.  When I did my Mustang years ago I was just amazed at the changes.  The engineering teams must have never slept, not to mention the poor factory teams who had to manage the changes coming out of engineering.     

 

Thanks Jay. So true; I still can't believe they could make aircraft at the pace they did, using nothing but slide rules and craftsmanship. I feel like as a world we are dumber now!

 

So the work with the engines continues to progress. When I brought the Eduard brassin set for the B-17 I had no idea how much work they involve, but they are exquisite and are starting to look the part.

 

First of all, and not a small feat, I redesigned the crankcase front to shorten the housing. I'm still striving to get better with my CAD skills, this one took me about 3 days to do!

 

akj7eL8.png

 

I had little faith that it would print okay, but lo and behold, I got 4 copies that were quite useable! Offered up next to the eduard part, I'm pretty happy I got "the look" reasonably close..

 

MxwkiNP.jpg

 

You can definitely see how much shorter they are though, which was the whole point in the first place.

 

FMkrXuB.jpg

 

24SesTA.jpg

 

Not looking too bad!

 

5NpZ3WD.jpg

 

fb3Ahwh.jpg

 

One issue I had with the Eduard stuff was trying to separate the massive pour stubs on the rear of the firewall and engine. In the end as I didn't have a saw that would cut deep enough, I had to mount the pieces on a temporary brass shaft and turn the excess off. Machining resin is very messy, but in the end I got it done. How did everyone else manage this?

 

VuzKZDR.jpg

 

Lots of engine bits that I somehow have to coax together. Please note the random unicorn was not used on the B-17 series......

 

jkdTHuw.jpg

 

After many hours of adding pushrods, prop governors and oil pumps(?) this is where they were at. Manageable for 1, but 4 is a long haul!

 

pIhwocO.jpg

 

Of course, adding ignition wires just took this to a whole new level of fun, but they really make the engine look complete and add some nice colour contrast to the darker areas.

 

9cEncAy.jpg

 

One more or less down, three to go!

 

h1ZLFGU.jpg

 

I'm on a bit of a roll with the engines and wings at the moment, so if I can crack on with these then I'll just have to worry about the fuselage later.

 

Cheers,

 

Craig

 

 

 

 

 

 

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Craig,

 

Your crankcases married nicely with the Eduard engines and they have that "right" look inside the "C" cowl. Some great work!. Those crankcases and cowls were a lot of extra work, but  you have yourself some pretty authentic reditions of the "C" engine section.

 

Unicorn? I thought that was the corpse of the "cowl/engine gremlin" you put to rest!

 

Terry

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13 hours ago, Cees Broere said:

Wow, those engines really look like the dog's danglies.

 

Thanks Cees! Still got a way to go on them yet, but they should like quite nice fronting a shiny aluminium wing :)

 

12 hours ago, TKB said:

Craig,

 

Your crankcases married nicely with the Eduard engines and they have that "right" look inside the "C" cowl. Some great work!. Those crankcases and cowls were a lot of extra work, but  you have yourself some pretty authentic reditions of the "C" engine section.

 

Unicorn? I thought that was the corpse of the "cowl/engine gremlin" you put to rest!

 

Terry

 

Thanks Terry! After our lengthy discussions I feel it wouldn't have been right not to try and correct them, and I'm glad I did! Time well spent. Hahaha! no that gremlin is still around, finding new things for me to change and upgrade ;)

 

Cheers,

 

Craig 

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  • 3 weeks later...
On 5/17/2020 at 3:28 AM, JayW said:

Good Lord Man!!!!!   What wonderful engines!   Well done.  I know how hard engine work is in large scale.  It is harder still (maybe exponentially so) in smaller scales. 

 

Thanks Jay! I'm pretty happy with how they came out; still a bit of work to do on them but for now, they need something to mount them on...

 

As you may recall a while ago I attempted to correct the outboard nacelles being too high on the wing. My first iteration was to cut the whole nacelle out and mount it lower, which was okay, but still required a lot of reshaping and work and was not repeatable for the at least two more B-17 projects I'd like to undertake in the future. I then hit on the idea of cutting out a whole section of wing which could then be cast and replace the existing nacelle in its entirety. 

 

I spent an exorbatent amount of time and effort replicating the turbocharger recesses into a redrawn nacelle in the correct position on the wing, and while the trial print worked perfectly well in ABS on the FDM machine, it took 10 attempts on the photo to get something that looked good enough to work with. I also made the assumption that because they were on different sides, the turbochargers must be left and right as well? Turns out that was a poor assumption - they are exactly the same both sides.... which meant my tenth attempt at the print was also no good :doh:

 

u9mJ2AO.jpg

 

How it's supposed to look:

 

cPKcOpl.jpg

 

How mine turned out:

 

qTK7MDQ.jpg

 

iQMe4PD.jpg

 

After much head scratching, I hit on the idea of using a mix of the kit parts and the redesigned nacelles, as THEN I could be sure the turbochargers would fit! 

 

yRmSrRF.jpg

 

Unfortunately, that meant a whole lot of grinding resin, which is most unpleasant due to the powder but also to my surprise, when I cut into the piece it was STILL filled with uncured resin

 

mfzmUdc.jpg

 

What a mess! I can see now why some people put drain holes in their prints. Funny thing is, this only happened on one side, not the other. Same drawing too.... weird!

 

Eventually I had it ground down to the point where I could graft the kit ones in.

 

Py1ID0t.jpg

 

Unfortunately that was not the end of my troubles. Another nasty little surprise was waiting for me in that due to the way the prints turned out, there was no way I could ascertain a reliable flat and square reference point when attaching the nacelles back into the wing! :doh::doh::doh: Yep, winning all round!!!! I finally resigned to the fact that despite the effort I'd gone through to make the resin prints work (even with alignment holes) the whole lot was a massive failure and needed to be binned.

 

Happily though, remember how I said the ABS prints worked perfectly? Well after digging them out of the draw (lucky I kept them) and doing exactly the same thing, I finally arrived at what I'd been trying to do.

 

mxusA0r.jpg

 

Still a long way from being finished, but I'm finally back on track after a lot of setbacks. Once these are ready, I'll be casting them in reliable silicone rubber moulds the old fashioned way!!!!!!

 

Cheers,

 

Craig 

 

 

 

 

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Craig,

 

December 22, 2014  "attempt to turn it into something resembling a D."  You do realize what an understatement that was on your part!

 

One thing you can never be accused of is being shy about cutting into plastic ... and once you do it's always astonding to watch it all come back together!

 

I don't like seeing you run into problems, but I have to confess, watching you get out of a jam is just as interesting as the "smooth sailing" (have there been any?) parts of your build.

 

You should a contestent on one of those survival shows. As innovative as you are along with your tenacity, you'd be the "last man standing" ... and asking "What's next!"

 

As always, keep up the fantastic work and again thanks for taking the time to share it with us.

 

 

Terry

 

 

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On 6/6/2020 at 6:48 PM, LSP_Kevin said:

Wow, that's an impressive amount of courageous work, Craig! My hat is off to you.

 

"Courageous".  Yeah my thoughts exactly Kevin.  Craig is nothing if not courageous.  The longer and more invested I get into a build, the more timid I become!  Well done Craig.  God man.

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Wow Craig, just caught up with this build (yes, all 70 pages of it!). I think that all of the superblatives have already been used up for this mammoth project, but for me, it is a series of eclipses...each renewed effort improving on the last in the quest for accuracy. well done Craig - I look forward to the next 70 pages! lol :)

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On 6/7/2020 at 11:48 AM, LSP_Kevin said:

Wow, that's an impressive amount of courageous work, Craig! My hat is off to you.

 

Kev

 

Thanks very much Kev! I'm still hoping there's a B-17 at the end of this! :) 

 

On 6/8/2020 at 2:31 PM, TKB said:

Craig,

 

December 22, 2014  "attempt to turn it into something resembling a D."  You do realize what an understatement that was on your part!

 

One thing you can never be accused of is being shy about cutting into plastic ... and once you do it's always astonding to watch it all come back together!

 

I don't like seeing you run into problems, but I have to confess, watching you get out of a jam is just as interesting as the "smooth sailing" (have there been any?) parts of your build.

 

You should a contestent on one of those survival shows. As innovative as you are along with your tenacity, you'd be the "last man standing" ... and asking "What's next!"

 

As always, keep up the fantastic work and again thanks for taking the time to share it with us.

 

 

Terry

 

 

 

Thanks Terry! I've got to say I enjoy the challenge of coming up with a solution, but I'm really looking forward to the aluminium skin hiding all the scars! :). Hahaha, yeah that'd be fun, but I'd probably get voted off because I didn't cause enough drama! :frantic:

 

On 6/9/2020 at 4:18 AM, JayW said:

 

"Courageous".  Yeah my thoughts exactly Kevin.  Craig is nothing if not courageous.  The longer and more invested I get into a build, the more timid I become!  Well done Craig.  God man.

 

I'd say the same of you Jay, you don't mind undertaking some major surgery yourself, and the results speak for themselves!

 

10 hours ago, Derek B said:

Wow Craig, just caught up with this build (yes, all 70 pages of it!). I think that all of the superblatives have already been used up for this mammoth project, but for me, it is a series of eclipses...each renewed effort improving on the last in the quest for accuracy. well done Craig - I look forward to the next 70 pages! lol :)

 

Hi Derek, welcome to the odyssey! Glad to hear you've enjoyed the journey so far. I certainly have, even if it hasn't been entirely smooth sailing! I had no idea this would go on for as long as it has, but I've certainly learnt a lot and the encouragement and support from everyone here has been the prime factor in motivating me to "get it right." I appreciate your comments!

 

Cheers,

 

Craig

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