V1.3 is out ! The Many Guises of the Dragon Lady - A Tentative Guide to External Differences of Small Wings U-2s

[kekelekou]

Hello fellow modellers and aviation enthusiasts!

 

I am pleased to share with you the booklet I have written in the last few months about the external differences of the first generation photo-reconnaissance, air sampling and SIGINT U-2s.

Each item that went though a modification is listed and a very short technical description is given.

Due to the confidentiality of the project and of the missions flown, many questions remain open about such differences. Even Chris Pocock, the top authority on the subject who very kindly answered to many of my questions and proofread the file, could not give definitive answers on some introduction dates or the functionality of several items.

So the scoop of the guide is limited to CIA or SAC articles dedicated to photo-recce, air sampling or SIGINT missions. There are waaaaay too many equipments flown by the NASA or the Air Force Test squadrons for me to cover them all.

This guide is by no means perfect of comprehensive, but I gave my best shot and I do hope it will be of some use for you to learn a little more about this fascinating high flying, aerial photography, jet-power motorglider

 

And I will be pleased to read any comment/remark/correction about either the content or the wording!

 

 

Enjoy the read! EDIT on 29th October 20022 : Link updated to v1.3, points to a short URL for analytics reasons

 

 

Edited October 29, 2022 by kekelekou
Image reuploaded

[Space Ranger]

Wow! That was obviously a labor of love.

[Mfezi]

Another wow! That is a fantastic document.

[Pinback]

Thanks kekelekou Will now look at them in a different light!

[Rob de Bie]

What a nice surprise to find this document! It's the first time ever that I looked in the 'resources' area, in appr. ten years of daily Britmodeller visits, but reading 'Cold War' and 'Modern' sections only. Maybe you could repost it in the 'Cold War' section, it would attract so much more attention I think..

 

You asked for comments, remarks and corrections, here are mine:

 

13.2  Q-bay hatch 3 windows

- you can't find a single photo either huh! Unbelievable after so many years..

 

13.3  Q-bay hatch 7 windows

- I made a 3D CAD model for the 1/72 kit(s), but the printing of the first (thinner) version wasn't successful

 

19.3  Double exhaust right of the dorsal fairing

- I have that mentally listed as the airco outlet, but I don't remember the source
- also mentally listed: there is a small air inlet ahead of the exhaust

 

21.2 Engine air intakes: Wider, straight but slightly higher ("Interim")

- you could add that the small inlet has a kink in the plan view. Jay Miller's Aerofax 'Lockheed U-2', page 56, has a photo of a U-2 approaching a tanker, Jay Miller's 'Skunk works', page 77, shows a U-2 on the tanker's boom. The former clearly shows the original small inlets, which cause a kink in the fuselage sides just ahead of the wing leading edges; the latter clearly has the enlarged but non-bulged intakes, and a continuous curve of the fuselage sides.

 

22.3. Air scoops under the belly: Three scoops

- I made a set of the three scoops in 1/72 scale

 

Suggestions:

 

a. you could add a section on the fuselage rear end diameter & length, U-2A versus C. It takes a trained eye to spot it. When the old Hawk U-2A was upgraded to a C, this change was included:

 

b. you could add a section on the inlet color, there are many variations there too. Recently I came across a photo on Ebay that showed chromate yellow ones:

 

c. can you make the tables on the last two pages available as Excel (I guess) files? They are nearly impossible to study in the PDF

Rob

 

My Seminar 1/72 U-2C under construction: https://robdebie.home.xs4all.nl/models/u2.htm

Edited October 15, 2021 by Rob de Bie

[Rob de Bie]

One more thing: a drawing of the Q-bay camera hatch for the A-cameras was posted on ARC a couple of months ago:

 

http://www.arcforums.com/forums/air/index.php?/topic/288638-francis-gary-powers-u-2-scheme/

 

Rob

Edited October 15, 2021 by Rob de Bie

[kekelekou]

Hello Rob! 
Thank you for your very informative  posts. 
I have to admit though that I’m struggling to spot the kink you refer to about the J75-P31 intakes. Any chance you can post a picture to help me noticing the difference?

And I’ll have to check this fuselage change, never paid attention to it so far.
 

I have been adding updates/corrections to the guide, so I’ll be happy to include your proposed air inlet colors (same as airbrake and wheel wells?) and also the two small rectangular air vents on the fuselage at mid-chord on late U-2C (variants to be checked).

 

Of course I can provide the tables in Excel format. Just PM me your email.

[Rob de Bie]

 

Kekelekou, here are the two photos from Jay Miller's Aerofax 'Lockheed U-2', page 56, and Jay Miller's 'Skunk works', page 77. The kink would not be that strange, the width of the J57 intake is quite a bit less than the J75 intake. And I don't think it's a sharp kink, but there has to be a transition somewhere. To me t looks like the U-2 was designed for the J75 from the start

 

 

The fuselage length is rather difficult to see. I usually use the rudder's trailing edge as a reference, and then you start to see it. The J75 required a bigger exhaust opening, that's all.

 

I will contact you by PM.

 

Rob

[kekelekou]

Thanks Rob, this makes things much clearer now!

 

After checking the pictures again, I still find it hard to distinguish the differences in the jet exhaust length. But thanks to you I have just spotted that the shape of the tail cone is a telltale sign of the engine type : a straight trapezoidal shape for the J57-equiped U-2s and a kinked one for the J75-powered articles. It may be the easiest way to make the difference between a U-2A and U-2C.

 

e-mail sent to you,

[Rob de Bie]

Your comments on the rear fuselage shape triggered another study, and my conclusions are different.

 

Here's an excellent photo of the U-2A rear fuselage shape. I see a near-perfect straight cone, with a double-curved last section, leading to a relatively small exhaust opening.

 

 

I haven't found a similar U-2C photo, but it is my impression (but only that for the moment) that the shortened rear section is straight, like the rest of the rear fuselage, creating a much larger exhaust opening. So my shape analysis is almost the opposite of yours!

 

Also I calculated the position of the exhaust opening in relation to the rudder root chord. In a random U-2A photo I measured approximately 70%, wheres a 'Pave Onyx' U-2C photographed in nearly perfect side view yielded approximately 40%. You can also see that the exhaust opening of the latter coincides with the trailing edge of the horizontal tail (or elevator) at the root.

 

 

Back to looking for that definitive U-2C rear fuselage shape photo!

 

Rob

 

[kekelekou]

Hello Rob,

 

The straight vs kinked analysis I was speaking about was about the drag chute housing, not the rear fuselage shape! 
I had understood your point about the fuselage length in the meantime. Your annotated pictures make it cristal clear.

I’ll update the document accordingly. Thanks again.

[Jochen Barett]

Very interesting!

 

Could you update pages 95-97 too please? They look a bit blurred to me.

[Rob de Bie]

27 minutes ago, kekelekou said:

Hello Rob,

 

The straight vs kinked analysis I was speaking about was about the drag chute housing, not the rear fuselage shape! 
I had understood your point about the fuselage length in the meantime. Your annotated pictures make it cristal clear.

I’ll update the document accordingly. Thanks again.

 

Ah, now I understand. I checked the drag chute housing shape, and indeed all U-2As have a staight lower side. But on U-2Cs I see different shapes: the straight lower side, and the kinked lower side like you describe. See for example this one, that I always assumed to be a U-2C. The rear fuselage shape and exhaust opening suggest a C to me, but just maybe it's an A? I mostly want to point out that the drag chute housing is not the most reliable identifier for a C-model.

 

 

Rob

 

 

 

 

[kekelekou]

This one is definitely a U-2F! 

The picture you posted above with the comparison of the aft fuselage length also shows that the J57 engined U-2A features a perfectly straight drag chute housing lower side, while the U-2C on the right side shows a weird design with both a double-kink of the lower side and a shadowed edge that doesn’t match the lit shape.

The photograph at the bottom of p41 and the ones p60 of Aerograph 3 by Jay Miller depict the « weird » configuration with the non-matching shadowed edge too.

One could conclude that straight housing means J57, and all the other ones (obvious kink or weird config) means J75.

 

And by the way, the picture of 56-6701 at the top of p41 in looks like the best sideway photograph of a J57 powered U-2 in my docs. You may want to use it for the jet exhaust length comparison.

Edited October 27, 2021 by kekelekou

[kekelekou]

A picture is often worth 1000 words :

 

 

The perceived inconsistency between the foreground edge and the one in the shade is pointed to by the orange arrow (no arrow on the leftmost picture).

 

About the U-2F picture : an sharper photograph makes the kink in the chute housing much more noticeable :

 

Edited October 28, 2021 by kekelekou

[kekelekou]

On 10/25/2021 at 7:01 PM, Jochen Barett said:

Very interesting!

 

Could you update pages 95-97 too please? They look a bit blurred to me.

Glad you like it! I have just checked the uploaded file, p96 looks pretty sharp to me, but p97 is a mess indeed! Another item to update in the next release. Thank you for pointing that out!

Edited October 27, 2021 by kekelekou

[Jochen Barett]

It seems to depend on the magnification I chose. When I zoom in the picture is getting clear (now).

 

Thanks!

[kekelekou]

Hallo Jochen! I promise I haven’t changed anything! The arrays in both appendixes are quite large, so they may require a bit of loading time. 
Anyway, I am glad it’s all sorted out.

[kekelekou]

The "perfect" side photograph of a U-2A is in my opinion the following one (the one I cited previously, and as long as the rear fuselage is concerned ) :

 

 

Which allows us to redraw the comparative lines on J57 and J75 powered articles :

 

 

Same results with 2 different pictures! Hurray! Conclusive results, thank again Rob.

Edited October 30, 2021 by kekelekou

[Rob de Bie]

On 10/30/2021 at 5:28 PM, kekelekou said:

 

Same results with 2 different pictures! Hurray! Conclusive results, thank again Rob.

 

Perfect indeed! I checked my Academy kit, and if judged this way, it has the J57 fuselage length, but the J75 opening diameter. Hmm..

 

Rob

[JeffreyK]

Oh wow, only just seen this, great research. I had covered the airframe differences in my research preparations until AFV Club poisoned the well for 1:48…. or have they?

The equipment setup differences will be a very welcome addition, I’ll have a good read through

J

 

[kekelekou]

Hello @JeffreyK! Enjoy the read!

[kekelekou]

Version v1.1 is out! Please proceed to the following thread :

 

[Hook]

Great stuff  - thanks!

 

Cheers,

 

Andre

[kekelekou]

My pleasure @Hook !

 

v1.2 is out by the way!