Urwerk EMC SR-71: Philosophy of Excellence from the Skies to your Wrist

The Lockheed SR-71 Blackbird is a plane so darn complicated that learning about its development effectively convinces anyone that it is a miracle it ever flew, let alone allowed to continue as a project.

Nearly every aspect of the design was invented from scratch or was extensively modified from advanced technology in other test planes.

Lockheed SR-71 Blackbird (photo courtesy USAF-Judson Brohmer/Wikipedia)

Given that the SR-71 would be flying at sustained cruising speeds of at least Mach 3.2 (3,400 km/h) at an altitude of 26,000 m/85,000 ft, much of the existing technology of the 1950s was not exactly up to the task.

Materials, manufacturing processes, technology, and understanding of physics all needed to be expanded or invented whole cloth.

A new fuel was invented in a partnership with Shell Oil, a new press was invented to work the very expensive titanium panels at temperatures of 815°C/1500°F, a new hydraulic fluid was invented in a partnership with Penn State, they even needed to invent an asbestos wrapped Kevlar wiring to work under high temperatures during flight.

Environmental factors were huge obstacles only discovered by trial, error, and a bit of luck. Cadmium coated tools were eventually abolished from the machine shop since cadmium flakes would quite literally poison the titanium, causing bolts heated up to 315°C/600°F during one or two flights to fail, with the bolt heads literally falling off.

Welded titanium panels had seasonally specific failures, failing incredibly fast when built in the summer but lasting indefinitely if fabricated in the winter. It all came down to water, public water supplies with high amounts of chlorine to prevent algae growth contaminated the welds when washed, leading to the exclusive use of distilled water.

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Aspects of the SR-71’s design were also crucial to not only function but pilot survival. Air inlet geometry took years to develop, assuring that repeated engine blowouts wouldn’t crash the plane, correlated with an automatic rudder control to maintain stability so pilots could even understand which engine was down as a blowout would cause the SR-71 to go from 9,072 kg/20,000 lbs of thrust to 7,200 kg/16,000 lbs of drag in less than a second.

Lockheed SR-71 Blackbirds (photo courtesy NASA/Wikipedia)

Titanium wing panels had to have corrugation and dimples added simply so that the material could expand in multiple directions at altitude to prevent the 500° exterior temperatures from curling or splitting the panels.

Most famously, the SR-71 was designed with fuselage panels that fit loosely together on the ground so that under high temperature flight they would expand together and seal everything shut, leading to the well-known issue of the fuel leaking from the tanks while on the runway (the custom, high ignition temperature fuel, JP-7).

All of these issues only scratch the surface of the development hurdles to overcome and illustrate why the SR-71 Blackbird has achieved mythical status in any discussion of the engineering wonders of the world.

In my mind, it is also why it makes perfect sense why the folks at Urwerk, in collaboration with a pair of watch and aerospace entrepreneurs from Dreamland Aerospace, have used the SR-71 Blackbird as the inspiration for a tenth anniversary edition of the groundbreaking Urwerk EMC.

Urwerk EMC SR-71 on the wrist

The new version adds some flight ready details of the SR-71 Blackbird as well as a special surprise, all while keeping the incredible UR-EMC movement from the very first EMC.

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Urwerk EMC SR-71

First, we should probably get reacquainted with the Urwerk EMC and what exactly it can do. Beginning as an exploration of precision and personal adjustment to fine tune a watch to the wearer, the EMC was designed to allow just that, individual adjustment, at home.

It starts with a movement built to be rock solid and run for days, sporting twin mainspring barrels in a series allowing for 80 hours of power reserve.

The balance wheel is a custom designed disc of non-magnetic, anti-corrosion ARCAP alloy (stated to be ARCAP P40 which is most likely a minor variation of the standard ARCAP AP4, which has a formulation of Cu54Ni45) that is shaped to optimize readability from an optical sensor.

That optical sensor captures, on demand, 24 half oscillations of the 4 Hz balance wheel over a period of three seconds to get a baseline for the current rate of the watch.

The brain of the EMC, a custom PCB (printed circuit board) with 16 MHz electronic quartz oscillator, compares the 24 half oscillations against 32 million electronic oscillations from the same period to calculate the standard deviation.

This number is measured in microseconds, and a +/-0.0000014 second deviation for a single half oscillation of the balance equals a gain or loss of 1 second per day.

Urwerk EMC SR-71

On the front of the watch, aside from the hours, minutes, seconds, and power reserve, is the precision indicator dial which displays the “instantaneous rate delta δ,” or put more simply, the variable change in the instantaneous rate of the oscillator.

This is displayed as a scale from -20 to +20 in single second increments. This can be read by first manually winding the onboard generator, via the crank handle on the right side of the case, which charges a super capacitor that powers the EMC brain.

Then a button on the lower left side of the case is pressed to display the current rate variation of your specific watch based entirely on your wearing habits.

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Crucial to precision timekeeping, knowing what your habits do to your watch allows for more accurate adjustments to be made so that it stays accurate based on how you wear your watch. This rate variation data can be used by you to adjust your watch using a fine regulator screw on the rear of the watch.

Back of the Urwerk EMC SR-71 with fine timing adjustment screw at top

Using a very long lever arm attached to the regulator stud, the fine regulator screw will move that regulator (lengthening or shortening the rate), displayed on its own larger scale to indicate the minute adjustments needed to affect the rate.

This allows one to home in on the exact adjustment needed to keep your specific watch accurate while being used according to your habits.

The fully mechanical movement uses the precise supplemental electronic monitoring to give you the best of both worlds, creating a mashup of space age technology and classic horology, something that would have been well understood by the engineers of the SR-71.

Updates and homages

When the original EMC was designed by Martin Frei, he took inspiration from favorite industrial design objects (such as vintage SLR cameras and aircraft gauges) and the components at hand, knowing that certain features of the movement and monitoring system would direct the aesthetic design.

Back of the Urwerk EMC SR-71

Fitting components together in a space that makes sense for the wearer will definitely direct the shapes somewhat, helping form the overall look of the watch.

Having to place a large crank with a micro generator puts a lot of packaging constraints from the beginning, and the result was a very industrial device aesthetic that flows naturally from the idea of a “wrist mounted time monitoring sensor.”

One could argue that this also follows the development of experimental aircraft, needing to balance functional requirements with the aesthetics of the machine, often giving precedence to the former.

The SR-71 is a prime example of function driving the entire endeavor yet resulting in a form that has become iconic to anyone interested in such things. The choices of materials, finishes, and layouts combine into something that nobody might have chosen without those restraints, but the outcome is incredible.

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The EMC SR-71 already has a lot of soul shared with the namesake inspiration, the original model in brushed steel and titanium, and most follow up variations do not really invoke the SR-71 Blackbird.

There was a previous black DLC version released in 2014 that is indeed similar in color, the essence of the updates take a precision timing device and turn it into a piece of experimental military kit.

The first major reason here is the inclusion of the literal titanium alloy from a crashed SR-71 (the exact alloy remains classified as far as I am aware).

This titanium panel was offered up by collaborators Jason Sarkoyan (watch designer and collector) and Dr Roman Sperl (aerospace engineer), co-founders of Dreamland Aerospace and passionate watch enthusiasts.

As an offering to the horological gods, the pair hoped the panel could be physically incorporated into the EMC SR-71 in some way, and Urwerk delivered. The metal from the panel was melted down and formed into billet to be machined into components for the case.

Urwerk EMC SR-71

On the front of the watch is a screwed bezel which has been redesigned to better highlight the seconds dial as well as the hour and minute display. Unlike the original which was a simple, flat piece surrounding these dials, the new bezel features raised rims around both, with flat flanges extending from the side where it is screwed in place.

A minor change to some, this update creates a much more explicit connection to aviation gauges which always sport this design feature (mainly to help isolate each gauge dial from any illumination spillover from adjacent dials).

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Structure and color

But the main use for the SR-71 material is a new crank to wind the micro-generator. Previously a fairly simple bar with single machined channel for weight reduction, now the crank looks like a landing gear or some inner structural member with complex ribs and internal bracing to minimize weight while maximizing rigidity.

Urwerk EMC SR-71 fold out crank arm

Obviously, this is dramatic overkill for a tiny little crank arm, but the aesthetics are the draw here and it looks incredible. It has a much bigger cross section that has been hollowed out from every side to remove as much material as possible.

In this context the complexity of the machining is both welcome and spot on, even if many of the members found in the SR-71 would have been simpler by necessity. It’s all a part of the updates to remind us of the SR-71 Blackbird in spirit.

Urwerk EMC SR-71 optical and EMC in yellow

On the rear of the watch, protective shields for the optical sensor and EMC brain are now a bright yellow, reminiscent of the yellow RESCUE signs just underneath the front cockpit windows, a color extending to the winding direction arrow on the front of the watch.

There are also screws with small amounts of red applied to the head holding the case back, something I can only assume is meant to allude to the practice of “torque striping” or adding a paint mark (often a stripe across the head and onto the structure) to denote the fastener has been tightened to the appropriate torque spec and does not need further inspection.

These are small details that add visual depth when inspecting the piece from all angles.

Of course, the black color comes from the look (and nickname) of the SR-71: Blackbird. Interestingly though, the exact paint used for the Lockheed SR-71, according to “Kelly” Johnson, Vice President of Advanced Development Projects at Lockheed during the development of the SR-71, was not, in fact, “black” black.

Urwerk EMC SR-71

Instead, it was a special formulation of a blue-black paint that helped increase emissivity when at altitude, reducing fuselage temperatures by up to 80 degrees, and when at speed would actually turn more blue than black. It was so dark however that it is effectively black, and I won’t fault Urwerk for not making it a super dark blue black!

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Missed opportunities

I do feel there were a couple missed opportunities with the design that would have dramatically improved the connection to the legendary reconnaissance plane.

As mentioned earlier, a very unique feature of the titanium panels on the SR-71 was the addition of corrugation and dimples to allow for material expansion under the high temperatures of flight.

I think the main case structure would look incredible if micro corrugations were added to the surface, something seen in some form before on the UR-111, UR-112, even the UR-100, UR-105, and the OG model, the UR-103.

If done in a manner like the SR-71 it could have really elevated the case design to feel even closer to the inspiration. And while they were at it, they could have added the subtle yet distinct red “keep-out” lines that run the length of the SR-71’s mid fuselage to protect the panels during maintenance.

A set of lines running around the central dials or at the outer edge of the case could have framed the entire watch and completed the look of an SR-71 homage.

Urwerk EMC SR-71 on the wrist

Urwerk did pay careful attention to the strap and its materials and markings, looking like a military issue, flight ready strap with sewn Mil-Spec designation patch on the inside, all in a NATO style with quick release Velcro.

I’ve seen plenty of straps that head in the direction of seeming direct from the military, but this might be the best version and most appropriate for an experimental aircraft from the height of US aviation research.

One final detail that does go to show that Urwerk will add little touches everywhere, the tip of the seconds hand has been updated from the original gauge specific shape. Now, the tip is in the silhouette of the namesake SR-71 Blackbird, painted in the same green Super-LumiNova found on all the dials.

The entire package is a fantastic reminder of just how awesomazing the original EMC was when it first launched, and how it changed ideas of what a high-tech mechanical timepiece could be. Just like how the Lockheed SR-71 Blackbird changed ideas of just what an airplane could be, even though they were literally living through the rocket age.

Since it is very limited, my only chance to enjoy this piece will likely be at the pleasure of Urwerk, should they still have any the next time I’m in town, but the sheer fact of its existence is enough to be excited for what Urwerk has up its sleeves for the future.

The brand has always been amount pushing boundaries and exploring imagined futures, something they have in common with all the engineers at Skunk Works for the past 60+ years as they brought to life some of the most incredible machines to ever fly. That feels appropriate since Urwerk has made some of the most incredible machines to ever sit on your wrist, keeping our eyes searching for the future we so rightly deserve.

Urwerk EMC SR-71 on the wrist

At least one thing is for sure, I don’t think the Urwerk EMC SR-71 will be leaking jet fuel unless at altitude, and I think that means I’m safe to try and break this one down!

  • Wowza Factor *9.49 A flight ready watch designed to allow precision adjustment customized to your own mission history, channeling the legendary SR-71 Blackbird? That is worth a huge wowza!
  • Late Night Lust Appeal * 94.9 » 930.651m/s2 I think if the watch itself isn’t enough to keep you up late enjoying the mix of classic horology and modern timing science then the sweet SR-71 vibes should do it!
  • M.G.R. * 68.9 The only downside to a movement this creative and capable is that it only shows the time and power reserve, and there are no visibly crazy mechanics to put it over the top, but it still is a top contender!
  • Added-Functionitis * Moderate A power reserve is the main added function but I have to give extra points to an on demand accuracy sensor, moving this into regular strength Gotta-HAVE-That cream territory!
  • Ouch Outline * 11.9 Dropping a gaming laptop on your foot! Some laptops are thin, light, and easy to hold onto. Some are heavy, bulky, and sport enough battery and ram to do some damage when dropped 3 feet directly onto your foot. But at the end of the day I would happily tend to a possible hairline fracture and bone bruising for a chance at the EMC SR-71!
  • Mermaid Moment * That crank, that strap! There are lots of reasons to love and Urwerk EMC model, so there is already an affection built in. But seeing the new details and understanding the connection is more than enough to fall head over heels all over again!
  • Awesome Total * 706.56 Start with the electronic oscillator frequency in Hz (16,000,000) and divide by the vibrations per hour of the ARCAP balance wheel (28,800), then add the number of hours in the power reserve (80) plus the numeric designation of the model’s inspiration (71) to land on a high flying awesome total!

For more information, please visit www.urwerk.com/collections/ur-chronometry/emc.

Quick Facts Urwerk EMC SR-71
Case: 47.55 x 49.57 x 17.58 mm, titanium, steel, and flown SR-71 titanium alloy

Movement: manually wound UR-EMC caliber, 80-hour power reserve, 28,800 vph/4Hz ARCAP balance
Functions: Hours, minutes, seconds, power reserve, instantaneous rate δ performance indicator
Limitation: 10 pieces
Price: 150,000 CHF

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