X: The R2 Builders Club plans

R2 Builders Club

The R2 Builders Club is an Internet group of R2-loving amateur hobbyists who, over the past 20 or so years, have come up with a set of “astromech” plans that people use to build their own Star Wars astro-droids. During that time they have devised two basic set of hobbyist plans, now known as CS:L (club spec. legacy) and CS:R (club spec. revised).

The basic idea behind the plans was to have a standard set of part dimensions that are fully interchangeable (within the spec), so builders have a common base of compatible subcomponents to work from. A builder should be able to buy a part from any club-compliant seller, confident that it will actually fit.

Using these plans people have built all kinds of homebrew R2-D2 (and related droid) robots, from elaborate welded aluminium droids to styrene plastic-clad droids with wooden frames to fibreglass droids. People have also engineered complex leg mechanisms: including droids capable of going from 2 legs to 3, and back, and sophisticated radio remote controls. None of those things are in the specs, though – those just lay out how the droid should look and its basic dimensions.

Neither plan is official in the sense of being blessed by Lucasfilm, but they reflect years of work by enthusiasts. And ironically in recent years many aspects of the plans have worked their way back into recent Disney-era productions. The sequel trilogy droids built by Oliver Steeples and Lee Towersey draw upon their club experience, and many background droids in recent Disney/Lucasfilm movies and TV shows have been loaned to the productions by hobbyist builders.

However, R2-D2 as a visual creation is not a simple design to replicate. There are tons of unique components and subtle details. So development of the club plans has been a complex process, with two main factors complicating matters.

CS:L / Club Spec. Legacy

First, back in the early 2000s there was quite limited source material available to the public. A lot of work was done with video screengrabs, published photographs, detailed pictures taken at exhibitions, and so on. Some of the original 1976 R2 blueprints were generally available in reproduction, but it seems they were not relied upon at that time. There was only limited access, I understand, to the preserved droid props owned by Lucasfilm.

Second, as far as I can tell there was never an effort made to focus on one specific screen-used droid or group of droids. And, if you’ve read over my articles here, the design of the R2-D2 props changed over time. In particular, there are numerous specific differences between the ANH droids, the ESB droids, and the prequel droids. In addition there are sub-variants of both ANH and prequel droids.

Unless you take the time to document all those minute differences, which up until now nobody seems to have done publicly, you’re never going to get a consistent design. There will by definition be subtle inconsistencies.

The 2000-era CS:L plans, therefore, represent a compromise: a composite droid incorporating certain features from different films and different scenes. The emphasis was on helping people build convincing droids that will delight owners and friends, not helping them build precise and historically accurate replicas of a particular movie prop. Another pragmatic component is that these early plans also reflect certain technical aspects of the machining options available to the builders.

Now, I am in no way criticizing this work. It reflects the group’s interests, priorities, and available data. It also represents a certain historical inertia as people invest money into producing parts to specific plans. However, it’s important to acknowledge that the club specs are an idealized composite design and not an attempt to document the historical reality of any specific screen-used prop. (ie: sometimes people think the club specs accurately reflect the original droid builds, but that’s demonstrably not true)

CS:R / Club Spec. Revised

In 2011 or so a group of three R2 builders (Daren Murrer, Chris Reiff, and Cole Horton) noticed some significant issues with the CS:L design and decided to develop more screen-accurate droids. Thus began a process of revising CS:L, reflecting more accurate measurements of some of the original props and other data. In 2012 they produced R2.0, their first revised specs.

In 2014 or so the team they dropped the R2.0 name and released their final CS:R specs. This design incorporate a lot of additional first-hand research, since they were kindly given access to a Kenny ANH R2 and a couple of friends, resident in the Lucasfilm archives. The length of the body is corrected over CS:L, and many detail parts are rescaled to match. The CS:R specs also highlight a number of specific differences between ANH and ESB designs.

However CS:R doesn’t fix all of CS:L’s errors, nor does it highlight the variations between the different ANH-era droids. There are a subtle differences between the robots built for the first film: the sole RC R2, the two Kenny R2s, the stunt R2s, and the “Identities” hybrid R2. The CS:R specs do not call out dimensions compatible with the “Uber” droid built by ILM for the prequels, which has dimensional differences from the Original Trilogy droids, since it was recast from earlier parts. And finally there are still some elements in the CS:R specs which do not appear on any screen-used original droid. (some described later on th is page)

The Michael Baddeley 3D print designs are largely derived from the CS:R plans.

The Future: HOW ABOUT CSR+ ?

Personally I think it might be cool for a future spec to be released, reflecting the historical reality of the different droids. This could, of course, lead to an insane proliferation of options, but I think they could be pared down to a few basics. I might suggest:

• • CSR + C: (an idealized composite droid; ie: what CS:R is now)

  • CSR + RC: (the 1976 RC R2 aluminium droid)

  • CSR  + KB: (the two main 1976 Kenny Baker aluminium droids)

  • CSR + ESB: (the 1978 fibreglass droids)

  • CSR + P: (the “Uber” prequel droid)

  • CSR + S: (the Disney-era sequel droids)

Of these, I suspect CSR + C, CSR + RC, and CSR + ESB would be the most popular.

I'm omitting lesser known variants, including the ANH stunt droids, the ANH "Identities" droid, and the "monster truck" prequel droid. Mainly because I don't think anyone's interested in those, and there are too many choices as it is!

And, no, I’m not offering to do this work, drawing up new plans! I’m just sitting here, armchair quarterbacking, as they like to say in the US. I’ll happily point out all the changes that would need to be made to CS:R to follow such a system, though.

Differences between CS:R and screen-seen droids

Although the CS:R plans were clearly researched and considered with immense care, I have noticed a few areas in which the CS:R specs do vary slightly from the screen-used droids. I don't discuss the CS:L differences here, because CS:L is a legacy spec, and its shortcomings are well known and mostly fixed with CS:R.

In some cases these differences probably arose because the CS:R specs rely on measurements of specific props. Now, I’m someone who has never had any access to any original props, and who has just documented screen evidence (the 4K film scans are essential) and other resources. So these are specific points I’ve seen based on photographic evidence.

• • The front octagon port detail. The octagon ports contain central details consisting of a stack of discs of different widths and thicknesses. The CS:R spec calls for a design where the difference between the outer and middle discs are greater than the middle and central discs (below left). Every photo I’ve seen shows a droid with evenly spaced disc diameters (below right).

• • The battery harnesses. The harness design differs from ANH and ESB. The CS:L and CS:R plans are closer to the ESB design, but they have a deep hinge slot, whereas none of the screen-seen OT and prequel droids do. (ie: the club design is markedly different from any original droid) The sequel droids have the CS-L/CS-R deep hinge harnesses, which makes the club design now technically screen-seen, but only in the sequel/Disney era.

• • The battery box proportions. There are three basic designs of the battery box that I know of. There’s the ANH asymmetrical design, the ESB asymmetrical design, and the prequel/sequel symmetrical design. The CS:R published PDFs omit the battery box designs, though the Astromech wiki shows ANH and ESB variants. The ANH spec looks accurate, but the ESB design is incorrectly symmetrical – I’ve never seen a photo of a screen-seen ESB droid with a symmetrical box.

  • Additionally the ANH battery boxes on the RC R2 had panels to cover the Kenny leg holes (ie: the same boxes were used on the RC R2 as on the Kenny droids), and these panels also had holes cut into them for the protruding windshield wiper motors that drove the droid along. The wipers were the same motor, which means the cutouts were not mirrored.

  • The battery box half-moon protrusions differ from ANH to ESB, primarily in the spacing of the two horizontal slots.

  • The CS:R dome topper silver ring width seems to be wider than almost all the screen-seen droids.

  • Rear panel height. The initial release of CS:R had a few back panels that were slightly out in position. This was called out by Robert Jackson and fixed by Oliver Steeples.

  • The bottom of the feet have two stepped or ridged sections of the foot skirt. These two sections are of the same height in the OT droids, but the CS-L/CS-R droids have a lower section that’s very slightly taller.

  • Unless I’m missing something, the two rear dome bumps are never described in the plans. People tend to make up all kinds of variants, sometimes even using commercial pushbuttons.

  • Also, unless I've missed something, the ANH-era battery box hangers are not included in any club plans. The absence of the hangers, and the resultant change in spacing, makes it impossible to implement an ANH-correct pair of battery boxes.

Copyright

This text was written entirely by and for 3Dsf.info. Feel free to make copies for your own use, but I ask that you not repost it for download elsewhere. The reason is I'm updating these pages all the time for accuracy and development purposes. So the most up to date page should always be available at 3Dsf.info!

The majority of the photos are copyright their respective owners. They're either the property of Lucasfilm or of various people who have posted images online; specific provenance is mostly not known. They're reproduced here for the purpose of criticism and research.

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