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HK's B-17F - 21/9 the photon steps up


brahman104

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21 hours ago, D.B. Andrus said:

 

Fencer

 

Are thinking about marketing a correction for the B-17 nose similar to your 109 products?

 

Cheers,

D.B.

As I am "lucky" owner of HK B-17G I'll just have to do this. It will follow Bf 109G-6/14AS and MiG-21MF(SM) noses. Strange thing - noses are the most suffering parts of many 32nd models!))

Edited by Fencer-1
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On 6/10/2019 at 12:09 AM, Fencer-1 said:

Yes, yes! You are absolutely right. The overall shape is more important, then some true dimensions. I just found them to give some "direction" to my own mind, as I am also "lucky" owner of this kit and thinking now about my own correction. There were some kind of reflections, thinking of the topic. I'll try to draw some Rhino files to see.

 

Please do! My research is far from infallible, so always good to have more than 1 pair of eyes looking into the information! I’ll be interested to see your findings as well!

 

cheers

 

craig

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6 hours ago, brahman104 said:

 

Please do! My research is far from infallible, so always good to have more than 1 pair of eyes looking into the information! I’ll be interested to see your findings as well!

 

cheers

 

craig

Thanks for starting research! It kicked me ahead with my own one.

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3 hours ago, Starfighter said:

I have no interest at all in the B-17, but I love this kind of research. The nose section of the HK model always looked very strange to me and I am glad to find out what actually makes it look strange. I will be following with big interest! 

 

G'day Ben, thanks for looking in! As you can appreciate with the amazing work you do, it's no small task to work out what's wrong, but it's somewhat satisfying getting to grips with the problem :)

 

The pesky #4 bulkhead

 

As you know from my previous posts, the STA #4 bulkhead is essentially where I believe the crux of the matter lies, well at least in beginning the corrective process. I feel if I can get this bit right, then the rest of the nose job should actually flow relatively easily from here (famous last words.... )

 

For such an important bulkhead, frustratingly the drawing of it is split over three sheets, which meant scaling and importing into Rhino would be a nightmare, as you can only import 1 background image per plane per time.....

 

I decided the best way forward was to print the sheets out, work out a suitable overlap to join them and then scan them at the highest resolution I could....

 

noRA1f4.jpg

 

For those following with their own drawings, I actually used sheet Z57, as it appeared clearer.

 

Taped carefully together, I then rescanned the sheet...

 

R8WDQPX.jpg

 

It was also time to remove the section marked '2' on the kit. The reason for this is two-fold. Firstly, it gives more surface area for the printed correction to bond to the kit and secondly, I believe to get the correct shape/taper just under the cockpit windows, the section back to #4 may not be parallel/concentric with the section forward of the leading edge. Time will tell!

 

QvEvV9i.jpg

 

Now that I had a complete drawing of STA #4, I had to work out its correct size in respect to the HK fuselage. This wasn't quite as easy as just measuring the kit STA #4, as there's wall thickness in the kit to contend with and the real #4 doesn't include the upper turtledeck coaming, that's a separate part. Also, I had to establish the true width of the kit's #4 by scaling the drawing to suit. In any case, this is what I worked out....

 

cb0x2Fn.png

Note* This is not the kit measurement - this is pre scaled. The corrected height is 74.4mm

 

Using that, I then finally was able to scale the STA #4 drawing and derive the true kit width at the fuselage centreline....

 

FTrJjzW.png

 

Easy right? Man for something that seems simple, that took a lot of head scratching!

 

Next up, I'll be establishing the true kit horizontal profile from STA #4 all the way to STA #1 - Quite a big moment!

 

Cheers,

 

Craig

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On 6/9/2019 at 2:26 AM, Fencer-1 said:

The full fuselage height at STA.1 is 53" in real scale, so it is 42 mm in 1/32. Full height at STA.3 is 83.66" that give us 66,4 mm in scale. All shape of STA.3 bulkhead formed by perfect circle with the radius of 43.66"(69,3 mm scale diameter or width), exept top flattened section. The flattening is located in the sector + 43.75/-43.75  degrees from the vertical axis. The cross-sections between bulkheads STA.4 and STA.5 are perfect circles with the radius of 45" or 71,4 mm diameter (or width we can assess) in scale. 

 

Compare the true dimensions that Fencer stated in his post to my reworked HK dimensions. Granted, it's not much, (73.96 versus 71.4mm) but I do think it's an important difference!

Edited by brahman104
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I hope I haven't scared any of you away with my findings so far! :)

 

Relatively happy with the scaling and incorporation of the #4, I now wanted to import the accurate cockpit enclosure drawing into the mix. Like so many others, this drawing is also critical to getting the shape right. I've discovered that despite all the factory drawings being scaled and dimensioned, there isn't just one drawing that is completely trustworthy for total dimensional accuracy. General arrangements are a good start point, but for specific shapes you can't beat the actual component drawing. I guess this is why I have nearly 10,000 drawings to sift through!:frantic:

 

I also ran into another small issue. Due to the receding angle of the #4 on the real thing, the rear wall of the upper turret will be off if I was to simply chop the fuselage where I currently had the datum point (this could be what someone was trying to tell me a while ago? - sorry!) To preserve the 4mm of straight turtle deck aft of the turret ring, I've effectively had to move the entire fuselage forward that amount. I was hoping to split the difference, but as I hope I'll demonstrate later, it was better to use the full amount. I don't think in the end it will affect the overall look - takeaway message: the vertical #4 on the kit was a real pain in the a#^e!!!!!!

 

This might explain better below:

Z3zGl26.png

 

The aft most red line indicates where the "new" #4 will sit to preserve the section behind the upper turret on the kit. Coincidentally, to not affect the bomb bay length, the fuselage will be approximately 4mm longer than it should be. This will be absorbed in the "straight" section so won't change anything I've already done.

 

Cleaned up, this is what it now looks like.

D8KqTHM.png

 

Once I get rid of the background drawing you'll never even know! :whistle:

 

Now it was on to importing the accurate cockpit drawing and getting to grips with another of those "subtle differences" so important to "the look."

sZknjOd.png

 

As you can see, the line of the structure under the windscreen is the wrong shape on the general arrangement drawing. Also of note, the shape of the structure under the side windows where it meets the fuselage is not straight like the HK kit (due to the totally round shape of their #3).

 

Once I get this drawn in, the next step is to print a trial shape to see how it merges with the existing kit. This will be the first real indication if anything of what I am doing here has been worthwhile, or if I'm just going off on tangents and confusing everyone! Hahaha!

 

Anyway, lots more to do!

 

Cheers,

 

Craig

 

 

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10 hours ago, brahman104 said:

I've discovered that despite all the factory drawings being scaled and dimensioned, there isn't just one drawing that is completely trustworthy for total dimensional accuracy.

Of course it's true. Just multiple dimensions and ordinates do matter in factory drawings. In general, the picture itself is for basic components arrangement and layout visualisation. It is not possible just fit these drawings to scale to get proper shapes.

Edited by Fencer-1
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Hi Graig, I've tried to take a closer look at the nose of the HK B-17G.

 

Starting from scratch, outlining the Monogram B-17G fuselage part, scanning it and enlarging it by x 1,5.

Superimposing this with the HK fuselage part, I get the same result as with the Air Corps drawing.

s4RKb9n.jpg

 

HK fuselage and nose superimposed with the Monogram outline (in blue).

I'm not sure but it looks like, if you move the nose part up by 3-4 mm's and would be able to bend or flatten the HK part at the top, where it

connects to the fuselage, making it 3-4 mm's flatter on the top, it's almost perfectly aligned to the Monogram profile of the nose...

IHAjGdS.jpg

Sketch showing the HK fuselage with a corrected nose cone (in red) The windows would also move up by 3-4 mm's?

If you shorten the HK fuselage parts at the front, you would get closer to the length of both the Monogram fuselage and the Air Corps drawings.

HK fuselage length: 63 cm/ Monogram fuselage length: 41,6 x 1,5 = 62,4 cm/ Air Corps Drawing: 62,5 cm

You would also get closer to the correct tail fin outline.

 

Hope this is of some use: Kent

Edited by kkarlsen
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8 hours ago, kkarlsen said:

Hi Graig, I've tried to take a closer look at the nose of the HK B-17G.

 

Starting from scratch, outlining the Monogram B-17G fuselage part, scanning it and enlarging it by x 1,5.

Superimposing this with the HK fuselage part, I get the same result as with the Air Corps drawing.

s4RKb9n.jpg

 

HK fuselage and nose superimposed with the Monogram outline (in blue).

I'm not sure but it looks like, if you move the nose part up by 3-4 mm's and would be able to bend or flatten the HK part at the top, where it

connects to the fuselage, making it 3-4 mm's flatter on the top, it's almost perfectly aligned to the Monogram profile of the nose...

IHAjGdS.jpg

Sketch showing the HK fuselage with a corrected nose cone (in red) The windows would also move up by 3-4 mm's?

If you shorten the HK fuselage parts at the front, you would get closer to the length of both the Monogram fuselage and the Air Corps drawings.

HK fuselage length: 63 cm/ Monogram fuselage length: 41,6 x 1,5 = 62,4 cm/ Air Corps Drawing: 62,5 cm

You would also get closer to the correct tail fin outline.

 

Hope this is of some use: Kent

 

G'day Kent,

 

This is some stellar investigative work you're doing here mate. Very interesting observations indeed. Reducing the 3-4mm out of the fuselage height will be quite a challenge indeed - I can only assume that since the majority of the fuselage is circular, that the same would apply to the cross-sectional width too? This is where things could get very tricky.....

 

Thank you very much for sharing your insights with us on this forum, as not only for me, but others have a lot of "food for thought" to digest here! 

 

I think initially I'd like to have a trial run at the nose correction and see how that looks mated up to the unaltered fuselage, but after that, what you've discovered here looks mighty tempting for a B-17 purist such as myself ;)

 

Cheers,

 

Craig

 

 

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On 6/16/2019 at 8:47 AM, brahman104 said:

You are absolutely correct Fencer. The shape of each component really brings home an appreciation of the overall look. How is your research going?

 

Craig

Initially I intend to make true scale dimension 3D nose section till 3E station, because there is cylindrical section with the radius of 45" follow behind 3D station. Then I will scale up whole thing to match HK model fuselage diameter. Will see the result. 

48084210056_31dd660089_b.jpg

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