For some time I had been thinking about building a U-2. First my interest was aimed at the prototype, but its bare metal finish and the very limited information made it a difficult project. I also liked the civilian registered CIA examples. With some Alps-printed decals I would be in business. And so I decided to do a dark blue CIA example. Finding an Academy U-2 proved to be rather difficult. It's long out of production, and not a single one could be found at various IPMS-Netherlands Nationals for example. In the end my modeling friend Eric sold me his Seminar U-2.
The genesis of this kit is pretty interesting. It all started with an Airfix model issued in 1984, that allowed construction of an U-2A or D (boxs says B/D) with small inlets. The same model was issued in the USA by MPC with a few extra parts (long 'canoe' spine, larger bulged intakes, extra cooling inlet and an extra bulged Q-bay hatch), allowing a C version too. Airfix reissued the model in May 2005, now listed as a U-2A/C/D, including the MPC parts. Reviews and build reports of the Airfix/MPC kit can be found on SMAKR (Derrick Winters) via the Wayback Machine, SMAKR (Mark Braithy) via the Wayback Machine, SMAKR (Kevin Ronayne) via the Wayback Machine, Datguy on ARC Forums and Modeling Madness.
|Airfix 04028||MPC 1-4311||Airfix 04028|
(Box art scans courtesy of Jerry Lawrence, Bill Banaszak and Eric Verschuur)
Academy copied the Airfix/MPC kit in 1987, rearranged the sprue lay-out, and gave it engraved panel lines. There are minor differences between the kits however. For example, the Airfix/MPC kit has a solid fin attached to the left fuselage half, whereas the Academy kit has fin halves attached to each fuselage half, Academy's pogo wheels are more detailed, and Academy's inlets are noticably narrower than the Airfix equivalents. A built-up example by Mark Davies can be seen on Hyperscale and IPMS Auckland. A very nice Academy all-black USAF U-2C can be found on Keith Goodman's website. Reportedly there is an Ace rip-off of the Academy kit, but I never saw solid evidence. Finally the Academy mould was sold to Seminar, also in Korea, who changed nothing expect they removed the Academy logo from the sprues. The earliest report of this kit that I found is from 1999. I don't think Seminar models are distributed in Europe or America. My example came via Australia. Noteworthy is that the box sides show a U-2R photo, and the box art also resembles a U-2R somewhat, especially the nose, which the artist made too long.
|Academy 1653||Seminar 2000|
The quality of the Academy/Seminar kit is reasonably good I think. It's a fairly simple kit, with only a few main components and not too many smaller parts. I have never read any negative comments on the shape, so it seems there are no big problems there, except the flat canopy. The panel line scribing is done nicely, and so far I haven't found obvious errors. The kit has two sets of intakes (small U-2A and bulged U-2C), two different optional spines, and optional small slipper tanks. This allows about any early U-2 version to be built. The wings show some warpage. The fuselage has a large number of sink marks. The rear half of the vertical tail is much too thick, ending in a very overscale trailing edge. I guess the original Airfix single-piece tail is better in that respect. A contrail-checking mirror is not included. Two Q-bay hatches are included: one that strangely lacks any camera openings, and a bulged one without windows as used in the UK for tests of the Advanced Location Strike System. The canopy has a strange pimple in the middle of the canopy. More serious is that the canopy is too flat. Some parts and the sprues have some flash, but nothing too serious. The decals look pretty bad. During construction I found some small errors; refer to the build report below for these.
I performed some measurements of the kit's dimensions. Fuselage length between the tip of the nose and the exhaust edge should be 203.4 mm according to the fuselage station plan in the Aerofax book, and I measured around 201.5 mm. A 1% error is quite acceptable I think. The fuselage width between the flaps scaled out within 0.5 mm, pretty good too. To be continued.
Apart from the above four more or less identical models, there are two more early U-2s in 1/72 scale. Rareplanes issued a vacform model of the U-2 in August 1979, and thus predated the Airfix model by five years. The kit is largely identical in layout, details and options to the injection moulded kits, and although it is a nice vac, it is not worth the extra work. Airmodel also made a vacformed U-2, reportedly a D, but I am not sure. Its catalog number was 152 (no longer listed on the Airmodel site), and it consisted of one sheet with fuselage halves, wing halves, and two horizontal stabilizer pieces, plus a clear vacformed canopy. No decals or small parts like the landing gear are included. Wilfried Eck of the "1. Plastikmodellbauclub Nürnberg e.V." built the Airmodel U-2.
(Pictures courtesy of Eric Verschuur and Larry Engesath)
The second-generation U-2 in 1/72 scale is available from three manufacturers: Rareplanes, High Planes and Special Hobby. The Rareplanes vacform was first, issued late 1988 with white metal parts and decals. High Planes 7235 contains TR-1A and U-2R options, and was discussed by Pin on BritModeller. Special Hobby 72024 represents a TR-1A, and was built by Chris Bucholtz on Internet Modeler. Special Hobby 72070 represent a Senior Span U-2S and a NASA ER-2, and was reviewed by Mike Grant on the Roll Models site, by Carmel Attard on Modeling Madness, and by Rigid on the Airfix Tribute Forum.
|Rareplanes RP8001||High Planes (72035 ?)||High Planes 72035||Special Hobby 72024||Special Hobby 72070|
I knew I wanted to do a civilian-registered CIA example: I really like the contrast between the aircraft's mission and the "oh, it's only a civilian aircraft" registration. Photos of nearly every number between N800X and N809X exist. After a long study I selected N803X as the aircraft that I wanted to do. Assuming that the registration was assigned to a single airframe (which I doubt somewhat), there are some six photos of this single aircraft. The photos appear to show one and the same aircraft, with the exception of some small underfuselage items.
According to the 1983 Aerograph book, N803X was 56-6683, possibly 'Article 350', the 9th production U-2A (not counting the proto), assigned to the Agency. According to this quite detailed Pinetree Line page, Article 350 / 56-6683 / N803X was not used for East Block overflights by 'Detachment A' (Wiesbaden & Giebelstadt), but possibly it was by 'Detachment B' (Incirlik & Lahore). However, during the Cuba crisis two CIA U-2Cs were loaned to the USAF, which until then had never updated its U-2s to C standard. One of them was 56-6683, and on return from a flight over Cuba on 20 November 1963, it crashed north-west of Key West, FL. USAF Pilot Joe G. Hyde was killed. Note: the N803X registration was later used on U-2R 68-10329, during its first flight on 28 August 1967.
|The kit-supplied canopy (middle) appears to be too flat, with the windshield set at a too low angle. I decided to try to replace it with a Starfighter canopy, since the U-2 fuselage was developed from the 104 fuselage. I tried both the Esci (left) and Hasegawa 104 (right) canopies, and they fitted pretty nicely. Of the two canopies, I liked the Hasegawa canopy best by far. The Esci canopy is some 5-10% larger than the Hasegawa canopy and indeed oversized when compared with a 1:1 Starfighter canopy & windshield.
The Seminar canopy has a strange pimple in the middle of the canopy, possibly an ejector pin? The white sun cover will hide it most likely. In reality, the sun cover is fitted inside the canopy, but painting the kit's canopy on the inside will not give the desired effect: it will emphasize the non-scale thickness of the part.
|The Hasegawa canopy almost drops in place, if I hadn't modified the model first to accept the larger Esci canopy. I had to restore the canopy sill with white plastic card. The sheet metal behind the canopy has to be made a little taller too, with a kink in the contour. Possibly one could also use the rear transparent part of the 104 canopy.
The new canopy really transforms the appearance of the model: it gives the model a face instead of a non-discript transparent bump. Plus it is moulded much thinner and clearer than the original canopy. A very good upgrade of the model! A contrail checking mirror needs to added to the new canopy.
I built two sets of inlets, because I initially thought N803X had U-2A inlets, and then changed my mind to the interim U-2C inlets. For reference I will report my adventures with both sets. In build reviews I had read about fit problems with the inlets. But no-one remarked that the Academy inlets are way too narrow, even for the small-intake U-2A version. And to compensate the boundary layer slot is much too wide. I solved the latter problem by roughly halving the thickness of the wedge on the fuselage that creates the boundary layer slot. The inlet parts still fitted reasonably after that. To increase the width of the inlets, I glued strips of plastic card to the outboard parts. They formed a wedge that was about 1 mm at the front. The inboard parts were also slightly modified, removing the step in the interior, about 3 millimeters behind the forward edge. Although I expected lots of problems giving the wider intake a nice curvature around the widened areas, this was quite easy. The two panel lines were rescribed and the U-2A inlets were declared ready. The photo shows the inlets after being painted satin black, so you can't see the wedges. The cross section of the inlet opening is not completely accurate, the corners should be sharper. I don't mean the radius, but the angle at which the outboard and inboard faces meet.
The kit's U-2C inlets have the same problem as the U-2A inlets: they are too narrow, and the bleed slot is too wide. I assembled the parts with a tapered strip of plastic between them, just like the U-2A inlets. The clearest photos of the interim U-2C inlets that I found are those of Powers U-2 wreckage on display in Moscow, and I used these as my guide. Looking back, the amount of widening is still not enough. Next I scraped and sanded the bulges off, creating the 'interim' U-2C inlets. When I installed the inlets on the fuselage I noted that adding a wedge-shaped filler wasn't the right answer, since the fit against the bleed slot wasn't very good. I should have added a strip between the inlet parts. Instead I added inversely tapered strips of plastic card to the upper and lower edges of the inlets. I used Milliput and Tamiya putty to make smooth inlet interiors, and painted it yellow in preparation for a chromate yellow interior. But I'm doubting that color choice now.
I found out later that the Airfix U-2 inlets are a bit wider, and they would have been a better starting point.
The kit has a strange cone-shaped exhaust. I later removed the cone-shaped area with knives and sandpaper. I still don't know whether the exhaust runs up to the edge of the fuselage, or whether it ends about 20-30 centimeters inside the fuselage. On the U-2R it ends inside the rear fuselage, but I still haven't found a good photo of the first generation U-2. Aerofax pages 83 and 120 show something but not enough. Judging from the frame internal diameter, the engine exhaust has exactly the diameter of the rear fuselage opening.
N803X clearly has an extended rear lower fuselage part ('sugar scoop'), shielding the engine exhaust. This shouldn't be too difficult to add. The Aerofax book has the fuselage station numbers of the extension. Note that two versions of the sugar scoop existed.
Another issue to be sorted out is whether the U-2A and U-2C versions had different rear fuselage lengths, most likely because of the larger diameter of the U-2C's J75 exhaust. I *think* I see it in most photos, but I'm not 100% sure. In an Airfix Lockheed U2 thread on the Airfix Tribute Forum it is also mentioned by poster 'rantingpedant 1'.
There's some indirect proof: in 1/48 scale, the Hawk U-2A and the modified Testors U-2C have different rear fuselages I clamped the fuselages of these two models together (see photo), and established that the Testors fuselage was 3.5 mm shorter. Similarly, Cutting Edge set CEC48287 'U-2A Conversion' contains a longer rear fuselage to be fitted to the Testors model.
Not surprisingly, the long and thin wings present some problems. Cut from the sprues they have a slight S shape in front view, due to warpage. However, they weren't too difficult to assemble correctly. First I glued the small insert in position, that closes the slipper tank opening. The inserts fit pretty well, although others reported quite some problems. I filled the gaps with superglue. Next, I test fitted the large lower wing insert. These required some shaving to sit perfectly flush. Then I taped the upper wing upside-down to a stiff panel, and pulled the mounting tab down with more tape to make the wing's upper surface completely straight. With the part taped down like this, I glued the insert with super glue. The result: one perfectly straight wing. The wing does not return to its earlier S-shape, since the combination of upper and lower wing now makes a rigid 'beam'.
The thus assembled wing does have a few problems. Firstly, the leading edge is fairly rough, and it required several applications of super glue and sanding. Secondly, the wing parts have some sink marks. Just outboard of the lower wing insert, the wing has sink marks on both upper and lower sides. More difficult to solve are the (rather shallow) sink marks all along the forward part of the flaps. These sink marks give the wing a rather unnatural profile, and I think it is essential to remove them. Thirdly, the trailing edge is rather thick. I measured almost a millimeter there! Some serious sanding was required there, but now I have a nice looking wing I think. I filled the holes for the wing supports, but left the hole for the pogo gear open.
After all this sanding, I added the tip skid. It's fit was not so hot, and lots of superglue was used to fair it into the wing. I sanded the skid to about half its thickness, which makes the skid look much more realistic. Between the flaps and ailerons, Seminar moulded a raised strip, which was removed during the sanding of the trailing edge. I think this strip is a bad attempt at simulating the fuel dumps on both wings and an infrared / ECM antenna fairing on the right wing, according to drawings and photos. But many photos, including my photos of N803X, show nothing installed there. I will therefore leave the wing's trailing edges clean. And after working hard to achieve perfectly straight wing, I decided I wanted bent wings, as all U-2s have when at rest. Working slowly with a small hair dryer, I gave the wings about 4 millimeters of droop. I still have to check with a taped-together model whether this is sufficient.
|Since my U-2 will be pretty boring with regards to details, I decided to do some extra work on the speedbrakes. The detailing of the speedbrake wells is not bad, but I wanted a more three dimensional look. I decided to build completely new wells, starting with a 9 millimeter wide three wall box. In the middle I added a vertical frame using two pieces of strip. Splitting the area left and right of the frame are vertical stringers. Lastly I added a horizontal U-stringer made by folding 0.005" card around an X-acto blade. I painted the wells in Humbrol's RAF trainer yellow, searching for a better chromate yellow match in the mean time. What remains now is some hydraulic tubing and the speedbrake hydraulic jack. The speedbrakes will probably also need rebuilds.|
I worked a little on the fuselage so far. It has sink marks near all the position pins, which require filling. The spine fairing behind the canopy has a continious slope, which is not correct. I made a kink in the middle, so the rear half runs horizontal. This gives the whole cockpit area a slightly bulged look, which appears more realistic to me. This U-2 page has a unique lower fuselage photo. It seems there is no 'fold' leading from the boundary layer slot down to the trailing edge of the wing, like the model has. It looks like some Milliput is required here.
The part that forms the lower hatch of the Q-bay has no camera windows at all, which is kinda disappointing for a recce aircraft! Interestingly, all my references up to say 2000 appear to be censored: not a single photo or drawing shows a Q-bay with camera openings, with the exception of two NASA Q-hatches in the Aerograph book. Only in Chris Pocock's latest book clear photos of for example the B-camera hatch are shown. In 1/48 scale, Cutting Edge sells a B-camera Q-bay hatch in resin (catalog number 48-289). It is the type with seven camera openings, of which four are round and three are square with rounded corners. According to the CIA, a jettisonable cover for the camera windows was developed to prevent the windows from getting dirty on wet runways. It was released at the same time as the pogos so that it could be recovered and reused. Since the Q-bay hatches are matched to different camera systems, it is interesting to note that the A2 camera was used in overflight of the Soviet Union.
The trailing edge of the rudder is horribly thick, as can be seen in the exhaust photo. I scraped the rear half of the vertical tail much thinner, and made a sawcut below the rudder to allow the thinned edges to meet each other. I guess I took out about one millimeter of thickness!
The J57 powered U-2A had a single large oil cooler inlet on the right side of the fuselage. On the J75 powered U-2C, this inlet moved to the left side, and a small oil cooler inlet was used on the right side. Luckily Seminar provides both inlets, although the instructions are not completely correct, and the shapes could use some refinement. There's a third and smaller air inlet on the bottom of the fuselage, slightly offset to the left of the centerline, and this is not included.
The airco outlets are absent on the model.
I had read numerous discussion on rec.models.scale about the colors of U-2s and SR-71s, and often a black with a weak blueish hue was mentioned. I was planning to paint my bird in a blueish black color, but I had to change the plans after consulting the relatively new sources. A downloadable PDF-version of The CIA and the U-2 program, 1954-1974 also reports that a dark blue color was chosen for CIA U-2s after tests (page 149). The instructions of Cutting Edge decal sheet 48-152 report the color was FS 35042. The Chris Pocock book 'Towards the unknown' has a definitely blue U-2 on the cover, and also mentions FS 35042. USAF U-2s never wore this color, they used a pure black. This photo on the Cold war black projects site shows definitive proof of the blue camouflage, showing both a black and a blue U-2. Further proof was provided by Tim Bradley, who posted on the Hyperscale forum a statement of someone who worked on the CIA U-2s in Taiwan: I have copies of these CIA papers, SB329, dated 8/29/58 and SB592, dated 11/9/61. Both list the paint as 'Lacquer Color Sea Blue ANA 607 18 Gal., Zinc Chromate Primer 5 Gal.' (SB being short for service bulletin).
I was afraid that 35042 would be too blue for modelers like me, too big of a shock. While building the model, I experimented to establish the best color to use. I first tried a 1:1 mix of 15042 and satin black (Humbrol 181 and 85 respectively), but this turned out to be almost purely black. Next was a 3:1 mix of Humbrol 181 and 85, which looked rather blue. Perhaps it looks better with a flat clear painted over? To be continued.
The speedbrake wells of N803X appear to be chromate yellow, a color also seen on other all-black U-2s. Most likely the inlet interiors are also in this color. These yellow parts will make quite a bold contrast I think!
The cockpits of early U-2s were painted interior green (at least side panels, the control yoke, rear bulkhead, canopy sill). Later models had painted medium grey cockpits. But even a recently used NASA U-2C had a partly green cockpit. Basically everything including and above the top longerons was green, the rest grey. The seat appears to have been grey in all aircraft.
I had the white serial numbers printed on an Alps printer. Rescue and walkway markings remain to be made or found. Rescue markings from an F-104 appear to be identical to those on the U-2, which is not surprising.
Aftermarket accessories for the U-2 in 1/72 scale are limited to the following:
U-2 external update set by Cobra Company
In 2013, a 1/72 scale U-2 white metal landing gear was offered on Ebay UK, no brand was mentioned
In 2013, Norm Dubay offered 1/72 U-2 goodies consisting of U-2C interim intakes and a Q-bay hatch for the B camera
Norm Dubay also cast a cooling scoops set
The following 1/72 decals are/were available:
Micro/Superscale 72-461: U-2A, NASA, 4080 SRW, 100 SRW
Micro/Superscale 72-462: U-2A/C/D AFFTC, 4080 SRW, 9 SRW
Wolfpak Decals 72-023: U-2C in the Sabre scheme
DrawDecals 72-U2-1: decals for U-2A 56-6696 of the 4080 SRW during an Australian HASP deployment (issued 2013)
DrawDecals 72-U2-2: decals for U-2A 56-6701 of the Edwards AFB Special Projects Branch / Aircraft Research Development Center (issued 2013)
DrawDecals 72-U2-3: decals for U-2D 56-6722 of the Edwards AFB Special Projects Branch / Aircraft Research Development Center (issued 2013)
In 1/48 scale, much more was available. Cutting Edge had an extensive line for the first-generation U-2 with twelve resin sets. Seven were discontinued in July 2006, the rest in February 2008 when Meteor Productions / Cutting Edge production was stopped. They are listed here because they can serve as inspiration for 1/72 scale.
CEC48287 'U-2A Conversion'. Includes flat spine, rear fuselage, and adapter pieces for the smaller intakes. Note this set requires CEC48293 too
CEC48288 'U-2A/C Super Detailed Cockpit'. See Hyperscale review
CEC48289 'U-2A/C B-Camera Q-Bay'. Includes masks for camera windows
CEC48290 'U-2E/F 'Ram's Horns' Conversion'
CEC48292 'U-2A/F Exterior Upgrade'. Includes short spine 'canoe', landing gear struts, wheel well, air brakes and wells, U-2C wing inserts, trapezoid & other antennas. See Modeling Madness review
CEC48293 'U-2A/D/E Seamless Intakes'
CEC48294 'U-2C/F 'Coke Bottle' Seamless Intakes'
CEC48298 'U-2A/C Seamless Exhaust'. Includes rear wheel well
CEC48299 'U-2C/F 'Interim' Seamless Intakes'. Applicable to all U-2Cs before 1965. These intakes are significantly different from the 'coke bottle' intakes in the Testors kit.
CEC48318 'U-2 HASP Conversion'. Contains 'hard nose' and side scoop
CEC48325 'U-2C 'Flat Spine' Conversion'. All U-2Cs were built with the flat spine; the long dorsal canoe was not installed until late 1965.
CEC48490 'U-2CT Conversion'. Adds a second cockpit to the Testors U-2C kit. Full airframe conversion, cockpit interior and ejection seat, and new clear resin canopy. It appears that this set was announced, but never issued
Cutting Edge also issued at least four U-2 decal sheets in 1/48 scale:
CED48149, with U-2A 56-6701 AFFTC, Edwards AFB; U-2C Article 360, CIA, May 1960 (the Powers a/c); U-2A 56-6715 4080th SRW; U-2A-1 56-6715, 4080th SRW, with HASP modification; U-2D 56-6722 6512th Test Group / ARDC. Reviewed on Hyperscale
CED48150, with U-2D AFFTC, 1967 Smoky Joe; U-2F Ram’s Horns 4080 SRW, Vietnam; U-2C N809X CIA; U-2A 4080 SRW overall gray; U-2A-1 HASP 4080 SRW, City of Sale, Reviewed on Hyperscale
CED48152, USAF Pave Onyx jets in the 'Sabre Scheme' of light and dark gray (100 SRW, 56-6692, -6700, and -6716), CIA U-2A N800X and N803X (overall sea blue scheme), overall black U-2F (4080th SRW, TDY in Vietnam), NASA U-2C 708 in 1980. Reviewed on Modeling Madness
CED48276, with CIA U-2As with spoof NACA and NASA markings, all markings schemes for the U-2CTs, and all markings carried by NASA ER-2s (U-2R/TR-1A) based at both NASA Ames and NASA Dryden. Reviewed on ARC
In 2013, Norm Dubay started offering a resin 1/48 scale Powers' U-2 conversion set, with U-2C interim intakes, three cooling scoops, a Q-bay hatch for the B camera, and a flat fuselage spine.
In 2016, Caracal Decals issued a 1/48 scale U-2A/C Dragon Lady decal set (CD48118), with ten marking options, stencilling and common markings, plus half a sheet full of serial number digits.
I found a few U-2 modeling articles in magazines:
Fine Scale Modeler, May 1990 issue, had a two-page article by Paul Boyer about building the 'Ram's Horn' U-2 from the Airfix/MPC kit
Scale Aircraft Modelling, August 2001 issue, had a six-page article by Frank Cuden, building an Edwards U-2 with satellite dropping test equipment and a 'howdah' sunshield
Airfix Magazine, June 1984 issue, had a review of the Airfix model
Scale Models Magazine, October 1984 issue, has a two page review of the Airfix model by Mat Irvine
Scale Aircraft Modelling Magazine, July 2001 issue, has 17 pages on the U-2 (first and second generations) including 5 pages of drawings by Mark Rolfe of the first generation
U-2 drawings that I found so far:
Aviation News, 9 June 1978, volume 7 number 1
Lockheed Blackbirds, by Thornborough and Davies, Mike Keep drawings
It took me a long time to determine what version N803X was, but now I'm pretty sure N803X was an early U-2C. The older books on the subject of the U-2 all have different interpretations of the model designations. This online CIA document on the U-2 activities adds to the confusion, claiming that the J57-P31 powered U-2A was designated U-2B. More recent books finally agree on the following two basic versions:
U-2A: initially fitted with the Pratt & Whitney J57-P37 engines, as used in F-100 and KC-135. This engine was not really suited for very high-altitude flights (flame-out and restart problems, smoke in the cockpit), but the preferred -P31 was not yet available. The first J57-P31s were fitted to CIA U-2As from spring 1956 on, keeping the U-2A designation (although the CIA book claims they were called U-2Bs)
U-2B: now described as a proposed bomber version, not built
U-2C: starting late 1958, early 1959 all remaining CIA U-2As were converted to U-2C standard with J75-P13 engines. The last update was finished in 1962, Air Force models followed later. There were two versions of the inlets. Both had the same inlet area, but the later type also had a strong bulged shape behind the inlet opening, my guess is that they reduced spillage drag. The early type inlet largely lacked the bulged shape, and is therefore often misidentified as a U-2A inlet. Photos of Powers' aircraft wreck clearly shows this early inlet type. Cutting Edge used to produce a set of resin 'U-2C interim intakes applicable to all U-2Cs before 1965' (set 48-299) for the 1/48 Hawk/Testors kit
I found a few photos that illustrate the inlet issue fairly clearly. 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. 'Lockheed Blackbirds' by Thornborough and Devies, page 32, has photos of two U-2Cs, the upper with bulged inlets, the lower with straight inlets. N803X as seen in the photos below has the interim large inlets, best seen in the first photo below, and also in the one-but-last photo.
Lockheed staged a photo session with Kelly Johnson and Frank Powers, using U-2C N803X, and an F-104 in the background. I found five different photos of the shoot. The only color reproduction was found in 'A-12 Declassified'. It clearly shows that N803X was painted dark blue instead of black. Johnson's suit is not a bad match for the color! :-) The photo clearly shows the large U-2C inlet of the non-bulged type.
The second photo comes from the Aerofax book (page 19), showing Johnson posing with his creation. Note the F-104 in the background as in the first photo. Outlets just left of Johnson's face are probably airco related.
The elevated view shown below probably shows N803X after the Johnson/Powers photo shoot, moved forward a few meters. The walkway lines appear to be white or perhaps gray, with red 'NO STEP' markings (hardly visible, but they are there). A Cutting Edge 1/48 decal sheet also appear to have white walkway lines with red 'NO STEP' markings. N803X had no red turbine warning stripe.
A nearly identical photo in black and white was found in Osprey's 'American spyplanes' (page 9). The main difference is the crew man missing (or erased?). According to the caption, the photo was made at Palmdale. Note how much clearer the 'NO STEP' markings are. A possible explanation is the use of different film, panchromatic instead of orthochromatic black and white film. Ortho film shows red as black, pan film shows a realistic grey value. Another interesting observation is the lack of a RWR antenna and fuel dump pipe between the flap and aileron. The shadow probably shows it most clearly :-)
'U-2 in action', page 20, has this photo of Johnson and Powers posing a conversation. Since Powers was held prisoner some 18 months after his 1 May 1960 shoot down and released in February 1962, and the aircraft crashed in November 1963, the photos were probably taken in this time slot.
William Wagner's 'Lightning Bugs' (page 1) has a photo with a slightly different angle. Pogo gear has a 'remove before flight' tag attached.
Another shot of N803X, showing its right side. Antenna wire just visible. I think I see several 'Remove before flight' tags attached to the aircraft's landing gears.
And yet another one, after landing on the taxiway. The large inlets can be seen again in this view.
This photo, published on the cover of 'The U-2 Spyplane - Toward the Unknown', was made with an unidentified U-2 fitted with slipper tanks. Again it shows a nice dark blue camouflage color. Note the orange-red pogo.
The last photo strongly appears to have been made on the same occasion (note for example the position of the sun), and identifies the aircraft as N800X for what it's worth. The camouflage color is undeniably dark blue.
Chris Pococks' "50 years of the U-2" is the first reference that puts dates/years on airframe modifications. I'm adding them here as I find them while reading.
page 226: shield under exhaust increased from 90 to 150 degrees
page 226: ECM equipment (System 13A) moved from slipper tanks to bubble fairing behind tail wheel
page 236: August 1965 decision to re-engine SAC U-2As with J75, making them U-2Cs
page 236: improved version of J75-P13 developed as P13B, increasing thrust from 15,800 to 17,000 pounds, during 1965-1966. Inlets with widened opening were needed for best performance. 'Coke bottle' inlets with widened opening introduced on U-2C/F/G during 1966-1967
page 240: System 20: a rearward facing small pod on the right wing's trailing edge. It contained an infra-red detector, to detect exhaust plume of intercepting fighters. Tested during 1967 for U-2R, but also retrofitted to all remaining U-2s
page 246/247: provision for drop tanks added to CIA U-2C/F/Gs during 1965-1966, since slipper tanks were now used for ECM. Tanks were modified Sargent-Fletcher fire bombs. However, ECM was moved to fuselage by the time the drop tanks were cleared for use. Photos on pages 246 and 248
Datguy shows his 1/72 MPC U-2A on the ARC forums
John53 shows his 1/72 Seminar U-2C on the ARC forums
Drooo shows his 1/72 Airfix U-2D on the ARC forums
Norm Dubay shows his 1/72 Airfix U-2 ALSS Part 2 on Hyperscale's Plastic Pix
Various 1/72 Airfix U-2s are shown on the Airfix Tribute Forum
Davedubya shows his 1/72 Airfix U-2C NASA on FighterControl
Alex Bigey shows his 1/72 Airfix U-2A Edwards on his site
Chockhead shows his 1/72 Airfix U-2 under construction on Britmodeller
Tigercat shows his 1/72 Airfix U-2C on Britmodeller
DH764 shows his 1/72 Airfix U-2C NASA on the Airfix Tribute Forum
Keith Peckover shows his 1/72 Airfix U-2D on Model-Scale
Bernard5802 shows his 1/72 Airfix U-2A 4080SRW on the Unofficial Airfix Modeller's Forum
Dietmar Kollmann shows his 1/72 Airfix U-2C NASA on ModellVersium (in German)
Norm Dubay shows his 1/48 U-2C build on Hyperscale's Plastic Pix: Wing, Inlets - 1, Inlets - 2, Inlets - 3, Inlets - 4, Inlets - 5, Scoops, Q-bay, Inlets and gear bays, Gear doors, Ready to close the fuselage
Bo Roberts shows his 1/48 CIA U-2C build on Hyperscale's Plastic Pix: 'My 4th one this year, 48th scale Testors U-2C'
Jan Forsgren shows his Testors 1/48 USAF U-2A conversion on Hyperscale in part 1 and part 2. Jan discovered that the wing roots are not aligned in height, left and right. I checked it on an old Hawk model, and indeed found an 0.6 mm difference left and right, using the front edge of the wing tab slot as a reference. With the fuselage 43.5 mm wide there, this gives an 0.8 degree angle if you stick something through both slots. One degree is quite noticable to the eye, and a quick check with the model confirmed this.
Evangelos Vassilopoulos shows his Hawk 1/48 USAF U-2A the on the Hyperscale forum
Tony Landis shows some great U-2 photos in a Hyperscale forum thread
'DMC' shows his scratch-built additions to the Testors 1/48 U-2C on the Bitmodeller forum
'Yardbird78' shows his 1/72 Academy U-2A in RoCAF markings on Britmodeller
Phil 'Booty003' shows his 1/72 Airfix U-2A on Britmodeller
Jessica shows her 1/72 Lockheed CL-282 on Britmodeller
Pier Citterio shows his Lockheed U-2C 1/48 by Italeri on Hyperscale, in the two color grey scheme