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Serkan Sen

Legendary Blackbird - Part 1: A-12 Oxcart (Italeri Conversion)

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8 hours ago, billn53 said:

I’d like to see the open fuel dump. Can you point me to some photos?

First M-21 fuel dump:

Lockheed M-21

 

This is the M-21 photo showing vents

A-12 (SR-71) Blackbird Belly Detail

 

Here is A-12 fuel dump:

A-12 Blackbird Tail

 

YF-12 fuel dump:

YF-12A_View (50)

 

YF-12 has also these vents:

YF-12 tail stabilizer

 

And SR-71 fuel dump:

The Lockheed SR-71

 

I like very much this photo:

Blackbird scale model

 

Serkan

Edited by Serkan Sen

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6 hours ago, Graeme H said:

Interesting in reading the data display with that aircraft saying it is painted, in a deep near black shade of blue.

There is a great AIAA paper about Blackbirds (I don't remember exactly from where I have downloaded but either from CIA or NASA site)

"Design and Development of the Blackbird:  
Challenges and Lessons Learned  
Peter W. Merlin*
TYBRIN Corporation, NASA Dryden Flight Research Center"

 

On Page 16:

"The Blackbirds earned their nickname because they were coated with a high-emissivity black paint for improved  
heat radiation, thus reducing thermal stresses on the airframe. The first A-12 initially flew unpainted. Early models  
in the A-12 and YF-12A series were subsequently painted black only on the periphery of the airframe where heating  
was greatest: on chines, leading and trailing edges, and rudders.  
Engineers soon realized it would be advantageous to take advantage of Kirchoff’s law of Radiation that  
describes how a good heat absorber, such as a black body any extremely dark object), is also an efficient heat  
emitter. Although convective heating decreases with increasing altitude, heat radiation occurs independently of  
altitude. Therefore, in late 1963, Skunk Works engineers decided to take advantage of the black-body radiation  
phenomenon by painting the A-12 fleet and subsequent variants entirely black."

 

The different shades of black even dark blue is all infact  black. The environmental and operational conditions caused black paint weathered.

 

Serkan

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Just now, Serkan Sen said:

There is a great AIAA paper about Blackbirds (I don't remember exactly from where I have downloaded but either from CIA or NASA site)

I found it here 🙂

 

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4 hours ago, Serkan Sen said:

I like very much this photo:

Blackbird scale model

And I know why... The wind tunnel models have a separate nose sections - that’s your style of modelling, Serkan! 😉 Without a doubt, tese models haven’t had any shape issues...

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1 hour ago, Nikolay Polyakov said:

And I know why... The wind tunnel models have a separate nose sections - that’s your style of modelling, Serkan!

This is the "Power of Habit"...

I did my PhD on CFD and WTT... 😁✈✈✈

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1 hour ago, Serkan Sen said:

I did my PhD on CFD and WTT... 😁✈✈✈

Ah, it’s very respected I must say! 🤝

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I have used YF-12 parts to make seamless front and rear canopies and prepared the master pieces to create molds:

1172.jpg

 

Then I have filled the molds with soft silicone:

1173.jpg

 

Next step is to cast canopy and windshield copies to use in forming final nose shape.

SR71Anose.jpg

p1050495-ad1146f5c7-original.jpg

 

Serkan

Edited by Serkan Sen

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4 hours ago, Serkan Sen said:

Next step is to cast canopy and windshield copies to use in forming final nose shape.

Casting the clear parts... It’s becoming more and more interesting, Serkan! :popcorn:

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2 hours ago, Nikolay Polyakov said:

Casting the clear parts... It’s becoming more and more interesting, Serkan! :popcorn:

I did it already for my Su-27IB conversion and Su-33UBM "What If" projects 🙂

1016.jpg

 

 

 

 

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15 hours ago, Serkan Sen said:

I did it already for my Su-27IB conversion and Su-33UBM "What If" projects 🙂

1016.jpg

 

 

 

 

Any concerns about the cast clear parts yellowing over time?

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1 hour ago, billn53 said:

Any concerns about the cast clear parts yellowing over time?

My existing clear epoxy resin needs additional compound to increase UV resistance. I have not experienced yet how the casted parts will look like after a year.

There are some crystal clear resin suppliers in ebay from UK claiming that their products are UV resistant and not yellowing ower time.

Serkan

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Yesterday I have casted some copies of canopy parts using PUR. The results are really good. These parts will be used in giving the final shape of upper front fuselage half.

1174.jpg

 

Also YF-12 clear parts will be casted using these molds to get seamless canopy parts.

Serkan

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The inner surface shapes of both canopies have been mapped onto plastic card using masking film and the windows were opened:

1175.jpg

 

The frame halves were placed and some details were added:

1176.jpg

 

Some improvements are needed to close the gap between the rear canopy and kit frame:

1177.jpg

 

Next is to fit front canopy and windshield.

 

Serkan

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The original SR-71 kit "glare shield" (or "instrument shroud" 🙂 ) is too big to fit inside YF-12 windshield. I have trimmed the original shroud to fit (the black half) and removed it from modified part (gray one):

1178.jpg

 

The temporary windshield was glued with super glue. The front canopy had also fit issues. But this was relatively easy to fix:

1179.jpg

 

The sharp edge around windshield was also rounded:

1180.jpg

 

Next step is to give front fuselage upper half to its final shape...

 

Serkan

 

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Hi Serkan,

A-12 is not my bag, but I've been wrestling my own Italeri 1/48 SR-71A Sled kit for quite a long spell now to no avail. I'm trying not to get discouraged and give up on my build with the advent of the new kit by @JeffreyK

With regard to your build - lately, on my build, for every issue I've overcome I seem to find two or three more issues. Last one is the kit windshield, which not only it has convex panel surfaces, but also it lacks the curve at the base, which adapts to the upper fuselage. It's this curve on the base of the windshield which actually gives the Habu that evil look when spotted from the front.

 

spacer.png

 

Here you've got a good piccy when viewed from the side

 

spacer.png

 

Then again, it's the wrong geometry on the windshield glass panels on the Italeri kit. Panels are flat on the real thing, just as on the F-106.

 

spacer.png

 

There, another one

 

spacer.png

 

Judging by the windshield on the kit; do you think I would end with a hole right in the middle of the panels if I take a file to try and make them flat? I haven't got the piece with me right now, but you seem to know your Sled pieces like the back of your hand. How thick could the panels be in the kit?

Very expert modelling skills you're endowed with, by the way!

Cheers,

 

Unc2

 

PS: Wonder whether or not you're going to make some clear resin windshields in 1/48th scale.

 

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12 hours ago, Uncle Uncool said:

Judging by the windshield on the kit; do you think I would end with a hole right in the middle of the panels if I take a file to try and make them flat? I haven't got the piece with me right now, but you seem to know your Sled pieces like the back of your hand. How thick could the panels be in the kit?

Very expert modelling skills you're endowed with, by the way!

Thanks for your kind words 🙂

It is not easy to build an accurate Blackbird derivative from existing kits available in the  market. At the beginning I thought that it shouldn't be so difficult...

 

The windshield is the one of the biggest pain in the neck. As you said having the Habu evil look is not possible with the existing kit parts and massive modification is required on this area including windshield, front canopy and nose. YF-12 kit has relatively better clear parts and therefore I have cloned these parts and used them as starting point. The windshield is not perfect but at least has correct height and width. It has also flat windows.

SR71Anose.jpg

p1050495-ad1146f5c7-original.jpg

 

I have also a mostly finished Sr-71B in 1:48 scale.

1038.jpg

1039.jpg

 

But I think I need to give a break when I complete this project before starting 1:48 mods.

 

The plastic itself is thicker than 1mm that can tolerate light sanding/filing. But I would recommend to support the surface from inside by gluing 1mm polystyrene card in any case.

 

Regarding to clear parts in 1:48 I will definetely do when I start that mods.

 

Regards

 

Serkan

Edited by Serkan Sen

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This will be the next one in my list 🙂

112.jpg

118.jpg

 

The whitebird not the lady 😁

 

Serkan

Edited by Serkan Sen

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If you don't need her I may be able to take her off your hands. How much is postage?

 

Ian

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45 minutes ago, limeypilot said:

If you don't need her I may be able to take her off your hands. How much is postage?

I am afraid that you won't get out of box what you want to have! Neither the bird nor the chick will be as expected (or dreamed)...

Serkan

 

Edited by Serkan Sen

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That's exactly why I'm still single!

 

Ian

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35 minutes ago, limeypilot said:

That's exactly why I'm still single!

 

Ian

You are a lucky man!..

Serkan

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On 10/15/2019 at 1:16 PM, Serkan Sen said:

This is the "Power of Habit"...

I did my PhD on CFD and WTT... 😁✈✈✈

Nice to see there is another Aerodynamicist here! 🙂

 

Gruß

R

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The  front upper half is now almost ready:

1185.jpg

 

The A-12 Oxcart will look like this:

1187.jpg

 

And M-21 will look like as follows:

1186.jpg

 

The planform view of single and double seater versions:

1188.jpg

 

The A-12B modification will be done after duplicating the front fuselage upper half.

 

Serkan

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On 10/16/2019 at 5:16 PM, billn53 said:

Any concerns about the cast clear parts yellowing over time?

Hi Bill,

Check out Hannants if they have the following product: GUNZE B522, MR.SUPER CLEAR UV CUT GLOSS SPRAY

 

I believe a coat or two of this product can protect any vacuform or resin clear part.

 

Cheers

Bill (aka Shalako)

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