XI: The Stears Manuals
Effects supervisor John Stears (right, operating the RC R2 with a Ripmax/Futaba M6) and his team were responsible for building nearly all the mechanical effects in the first Star Wars film. All the droids which rolled around on wheels – the radio-controlled R2-D2, the “mouse” robot, Luke’s ill-fated “Treadwell” robot, and so on – fell into that category.
Stears produced a set of manuals for each mechanical droid that his crew built in 1976. The instruction sheets documented the various features and ensured any future operator or technician would be able to work on them.
The documents were professionally typed on A4 paper using an electric typewriter, and included photographs of the robots and of key components. I don’t believe they were mimeographed, which is process that required stencils and thus was not compatible with the reproduction of photographs.
At least one copy of the manuals was bound in red vinyl binders. These binders were adorned with illustrations of each droid, and the smaller version of the adhesive triangular “The Star Wars” stickers that were used during production. The illustrations appear to have been made by applying Tippex (ie: white-out/correcting fluid/Liquid Paper) silhouettes, with details drawn in with pen.
The manuals formed the germ of the articles which were later published in Electronics Today and Electronics Tomorrow magazines in 1977. (excerpt below)
Stears apparently kept the red binders following the end of production, and retained them as mementos.
At some point, many years later, Norman Harrison of Norank Engineering paid Stears a visit and purchased the manuals and copies of R2-D2’s blueprints from him. The Norank acquisition of the papers is likely to have occurred shortly before 1993, when Stears and his wife sold their Buckinghamshire country mansion to Ozzy Osbourne and relocated to California. There is no evidence that Norank was involved in the production of the original 1976 Star Wars droids (and thus that wasn't how Norank obtained the documents).
Norank’s heirs sold the set of red-bound binders via regional UK auction house Ryedale in 2023. They are currently up again for auction via film-specialist auction house Propstore.
The Manuals
There were manuals written for:
R2-D2
Dome Robot
Umbrella Robot
Baby Box Robot (now known as the “mouse” droid)
Stick Robot (now known as the “Treadwell” droid)
Unknowns
How many copies of the manuals were made by production in addition to the set Stears retained? At least one set of photocopies, without binders, was sent to ILM in California, where the R2 manual was used by William Shourt to repair and improve the RC R2. Another set of photocopies is known to be in the possession of the estate of the late Charles Lippincott, who was in charge of marketing for Star Wars.
How many copies of the manuals were bound in the red binders? How many were loose photocopies? Is the red binder set up for auction the sole set that was made?
Who drew the cover illlustrations? Apparently according to Norman Harrison, it was Stears himself. This is entirely possible, but sadly there are some questions about the reliability of the Harrisons as sources, and we probably have no way of verifying the claim.
Why is R2 drawn with the body at such a weird angle with its barrel backwards? It looks like someone copied the rear view photo (below) and then incorrectly drew the front of the body where the back should be. It seems odd for Stears to have made such a mistake.
Did any version of the manual consist of the original typed pages with the original photographs? Or were all known copies of the manual made of photocopies, and the original typed pages destroyed or lost?
The R2 Manual
The following text has been retyped verbatim from known pages of the manuals. Note that at this time not all pages of all manuals are publicly available. Spelling and punctuation errors have not been corrected. Formatting has been loosely emulated (except for things like the typewriting convention of two spaces after a period/full stop). I have a glossary of certain unusual terms at the end of this document.
This manual has proved a valuable source of information on the original Star Wars droid. As documented elsewhere on this site, the metal body was made at Peteric Engineering in England, with additional details and mechanical components by C&L Developments. Lights and mechanisms were by Stears' team at EMI Elstree.
A scan of a page from the R2 manual courtesy Propstore.
MECHANICAL R.2. UNIT
GENERAL
This version of the R.2. Unit is radio controlled and intended as a three legged rolling version of "Kenny's R.2. It has three forward speeds but no reverse and is steerable. It has provision for the change from the two legged to the three legged configuration. The front leg "drop" can be achieved by remote radio control.
It has three blocks of simulated computer lights (F.O Displays) in the head together with two pulsating lights. The head matches the version used in Kenny's R.2 in all important details.
MECHANICAL
In order to achieve forward motion the two feet attached to the standing legs are equipped with individual geared traction motors driving the twin in-line wheels via chain and sprockets.
Steering is achieved via a mechanism installed in the third (front) foot. This mechanism is powered by a servo unit and is proportional and self centring. The foot has twin in-line wheels which should remain parallel to one another from one lock to the other.
The foot and front leg retract inside the body and are held by safety latches in the upper (hidden) and lower positions.
ELECTRICAL
There are four basic electrical systems.
(1) The traction motors and leg drop mechanisms are operated from a 36V system. Speed control is achieved via a servo/micro switch mechanism and associated relays giving 12-24-36V drive to the two traction motors.
(2) The steering servo is supplied with 6V as are the F.O. light disc drive motors.
The two 50w Q.I. lamps which are part of the F.0. light mechanism are supplied with 12V as are the light pulser drives.
Radio circuits are supplied by a DEAC switched by a slide switch in a recessed panel on the lower left hand side of the body shell.
All connectors are of a "push on' automobile type except for the radio control system which uses its own three pin plugs and sockets.
6V and 12V circuits driving the head display lamps and motors are switched by a large toggle at the lower centre of the body shell at the back.
(a) The two 6V cells comprising the 12V circuit are removable for charging purposes. The six traction batteries are not removable and must be charged in situ.
(b) In the two legged configuration it is essential that the Robot be balanced or supported.
(c) In the three legged configuration the leg ties must be in position for stable performance, in particular: when executing tight turns.
R.2 MECHANICAL PLATE 1 GENERAL - WITH HEAD AND REAR PANEL REMOVED
1. RADIO CONTROL GEAR. HEAD LIGHT PULSES UNDER.
2. HEAD RING
3. SHOULDER BEARING
4. 2 X 6V CELLS FOR HEAD LIGHTS AND STEERING REMOVABLE
5. TRACTION BATTERIES NOT REMOVABLE 6 X 6V
6. HEAD LIGHT SWITCH
7. FRONT FOOT (STEERING)
8. REAR FEET(DRIVING)
9. LEG DROP MECHANICAL
10. RADIO ON/OFF SWITCH
11. LEG DROP SOLENOID
R.2. MECHANICAL PLATE 2 RADIO CONTROL GEAR
1. Rx DEAC
2. Rx
3. LEG DROP SERVO & MS
4. STEERING SERVO & MICROSWITCHES (OLD SYSTEM)
5. SPEED CONTROL MICRO SWITCHES
6. SPEED CONTROL CAM & SERVO
7. DRIVE MOTOR CONNECTIONS
8. CHARGE 36V TRACTION BATTERIES ONLY
MECHANICAL R.2 HEAD REMOVED PLATE 3 PULSATING LIGHT DRIVES
1. THROB LIGHT DRIVES
2. THROB LIGHT CONNECTIONS
3. LEG DROP SOLENOID
4. TWO 6V CELLS (HEAD & STEER CIRCUITS)
R.2 MECHANICAL PLATE 4 HEAD INTERIOR
1. QI LIGHT SOURCE
2. DISC MOTOR
3. PULSATING LIGHTS GREEN/YELLOW
4. REAR FIBRE OPTIC (F.O.) DISPLAY
5. QI LAMP AND LENS
6. DISC MOTOR
7. FRONT F.O. DISPLAY
8. PULSATING LIGHTS RED/BLUE
R.2 MECHANICAL PLATE 5 LEG DROP RELEASE
1. LEG DROP SOLENOID (ATTACHED TO LOCKING ARM)
2. DAMPER
3. BODY-TILT TENSION SPRINGS
4. LOCKING ARM
5. LOCKING ROD
(Missing page)
R.2 MECHANICAL PLATE 7 DRIVING FOOT
1. DRIVE FROM GEAR BOX
2. SPROCKET (CHAIN DRIVES BOTH WHEELS)
3. FOOT RETAINING PIN
MECHANICAL R.2 TX DETAILS
LEG DROP
BLUE
SPEED FORWARD ONLY
MAX MIN
STEER
(WITH ADAPTOR)
L R
BLUE XTAL. 27.255 MHz
MECHANICAL R.2
GENERAL NOTES ON PLATES
T.X. DETAILS
Left hand stick controls speed.
Stick pulled right back (towards operator) is zero - fully forward is maximum. It may be necessary to adjust trim control to obtain full range.
(Stop - slow - medium - fast).
Right hand stick is fitted with a simple mechanical adaptor that reverses the stick movement so as to provide true directional steering. (The steering servo and mechanics produce 'reversed' steering.)
Leg dropping is triggered by the auxiliary toggle switch. It is most important to ensure that this switch is in the 'off' position before switching off transmitter and receiver. Failure to do so will leave the leg drop solenoid energised and will cause overheating.
PLATE 1.
Shows the relative positions of all important components.
Removal of the head and rear panels as shown provides access to mechanical and electrical parts housed in the body.
It should be repeated that the traction batteries are not removable and must be charged in situ. The two 6V cells for head lights and steering are removable.
All cabling to batteries is done with twin cable - the conductors being connected in parallel.
PLATE 2.
The Rx deac is a push fit in it's housing.
The Rx unit is mounted so as to give access to xtal and servo sockets and should not be moved. The aerial has been shortened and must be led to the outside of the head and extended with fine enamelled wire kept, as far as possible away from the body. (Hanging and/or trailing is alright). Remember that the effective length of the aerial is that length outside the head.
(Missing page)
PLATE 5.
Shows main components of leg drop mechanism at top end.
To raise and lock the leg in its upper position inside the body the following procedure must be adopted.
(1) Remove head to gain access to drop mechanism.
(2) Push body back and tilt so that the legs and body are vertical and in line.
At this point locking rod (5) should latch with locking arm (4).
(3) Holding body in vertical position release lower leg lock (down position) and push leg upwards until top leg lock engages.
(4) Replace head.
(5) Hold, support or balance robot in vertical position. (If the body is allowed to drift out of line with respect to the legs the leg drop mechanism will trigger and the third leg will drop).
Note that the 'leg drop' solenoid does not in fact drop the leg directly but allows the body to tilt (assisted by body tilt suspension springs) thereby triggering the leg drop proper.
PLATE 6.
When the 'leg drop' action is required followed by a move off, the leg distance wire holds leg at correct distance from body. It will not, however, hold this distance when the robot is turning as the inside leg on the turn tends to move foward, upsetting the overall balance.
When the robot is required to run in its three legged form, the distance struts should be fitted.
R2 Notes
The manual offers fascinating insight into how the original radio-controlled (RC) R2 was built. For example, Robert Jackson and Mark Kiger of OpenR2 were able to determine the make and model of the leg drop solenoid from close examination of the images. Here are a few other observations.
The manual documents the droid as it was in its second build stage - filming at EMI in 1976. Essentially the RC R2 went through five different revisions that I know of. First, it was built in early 1976 and flown to Tunisia for the desert scenes. It suffered some faceplant damage after the middle foot latches failed, and it generally experienced operational problems. Second, it was repaired and modified back in England, and a modified middle foot steering mechanism (the "mystery box") was installed. Third, it was sent to California where ILM's William Shourt rebuilt it, removing the steering servo altogether and converting it to a tank-like differential steering system with passive middle foot casters. This, and keeping it in three-leg mode, rendered it considerably more reliable. Fourth, Shourt revised the droid again in 1977 by adding a head turn motor. This is why we can see it spin its head in the "Making of Star Wars" TV special. And fifth, the droid was stripped and rebuilt, but ultimately basically unused, during the development of the Empire Strikes Back.
Another point of interest is that specifics are not detailed. Nowhere does the manual list the actual types of motors, servos, relays, radios. This document was not intended to be a full repair manual.
R2 had no linear speed controls, but did have three separate voltage-controlled speeds. No provision for reverse.
One of the transmitter sticks was used to control a servo in the droid which physically moved a switch to change speeds.
The Lucas 17W windshield wiper motors that power the feet are coyly referred to as "traction" motors.
A serious problem was that the foot motor batteries were not designed to be removable. Neil Anderson's C&L recalls that they were held in place to the internal rings with gaffer tape. You had to charge them inside the body, so if the batteries drained the filmmakers had to wait ages for them to recharge. Producer Gary Kurtz was very unhappy about this, commenting in a later interview that “the batteries would run down too early, and they were hard to replace.” By contrast the Empire droids had hot-swappable batteries.
The power circuits had twinned cabling for redundancy, which sounds like a very wise approach.
The halogen (QI) bulbs for the fibre optic cables were 50 watt 12 volt. Those would have been pretty warm and eaten a lot of power.
The manual confirms that the slide switch hidden in the left pocket vent was used to control the radio receiver power.
The RC R2 could not turn its head at this stage. There were no provisions for a head turn motor. All scenes in the finished movie where R2's head turns are either operated by Kenny Baker inside the droid or someone actually lying down and hand-operating a dome.
The droid could leg-drop, spring-powered, using a servo-controlled release system triggered by the left-hand button/switch on the Futaba M6 transmitter. However it couldn't pull its leg up to return to 2-leg configuration. You had to remove the droid's head to access the leg latches to reset the mechanism. Behind the scenes photos show that this was a two-person job.
The document states that the droid cannot leg drop, roll forward, and turn, because the "leg distance wire" (there were actually two thin steel cables linking battery boxes to skirts) can't hold the legs properly. In fact the design was very problematic. For one thing, on a turn the two foot motors couldn't change speed to accommodate the movement. (when you've got two axles side by side, like you do with motors in each R2 foot, the outer wheel travels further than the inner wheel when the robot turns)
Even leg drop and straight motion was still a problem, because the shoulder joints couldn't handle the tension and the legs would splay. Neil Anderson of C&L recalls discussion of reinforcing the shoulders, but sadly that was never done fully at EMI.
The manual admits that the “distance struts” must be installed when driving the robot around.
There's an interesting reference to the RC antenna wire having to hang on the outside of the metal shell. The Faraday cage that was the all-aluminium RC R2 droid must have affected radio reception.
Filming in Tunisia. You can see the radio receiver wire has been taped on the outside of the dome in an attempt to get better control range.
The Umbrella Robot Manual
This robot is the multi-armed droid seen in the droid “auction” scene early on in the film. It was fairly complex, equipped with a spinning cross-shaped thing on top, and a pneumatic digging shovel, but neither detail was ever seen operating in the film. Production referred to it as the umbrella robot, and it was never named in either the film or the script, but later marketing named it the “WED Treadwell” robot for the purpose of selling toys, etc. (though the name “Treadwell” was the name from the novelization for the stick robot)
It's also seen trundling past Tosche Station during the deleted drinking scene with Luke and Biggs. A modified version of the droid is also seen, static, during the Echo Base scene in Empire when Chewbacca yells “where the hell have you been?” to Han.
UMBRELLA ROBOT
GENERAL
This is one of the group of 'tread' robots.
Tread robots have 'tank-like' bases equipped with individually driven tracks, power supplied and radio control equipment.
The umbrella robot has a shell covering the basic tread robot base and concealing the wheels and tracks. On this shell is mounted a turntable and central column equipped with a rotating 'head'.
Around the central column and hinged on the turntable are seven jointed arms, six of which are equipped with special instruments (the purpose of which is only known to the Production Supervisor), the seventh is equipped with a shovel. This arm is practical and operated by air. The turntable can be revolved by radio control, likewise the head.
MECHANICAL
Motive power is provided by two permanent magnet D.C. motors having linear voltage/speed and torque/current characteristics. Each motor drives one track via a coupling and simple worm reduction box and drive wheel. Each motor has it's own independent speed control (forward and reverse) so that steering is achieved by normal tracked vehicle methods.
Track tension can be adjusted.
ELECTRICAL
There are three electrical systems:
(1) Eight 6v lead acid jelly cells in series - parallel to supply 24V for traction purposes.
(2) One 6v cell for auxiliary circuits - (rotating head and turntable.)
(3) A Deac supplies the radio receiver circuits.
UMBRELLA ROBOT PLATE 1. GENERAL
1. ARM TURNTABLE
2. RADIO CONTROL GEAR UNDER
3. REAL AERIAL TAPED TO DUMMY
4. DUMMY AERIAL
5. ROTATING HEAD
6. PRACTICAL ARM (PNEUMATIC)
7. SERVO/MS UNITS UNDER
8. BATTERY COMPARTMENT 2 X 24V STACKS IN PARALLEL + 1 X 6 V AUX.
UMBRELLA ROBOT PLATE 2. PRACTICAL PNEUMATIC ARM
1. RAISE/LOWER RAM
2. AIRLINES
3. SCOOP OPERATE RAM (INSIDE)
4. SCOOP
5. ELBOW
UMBRELLA ROBOT PLATE 3. TURNTABLE MOTOR
1. MOTOR
2. TURNTABLE
3. RING GEAR
4. GEAR BOX STACK
UMBRELLA ROBOT PLATE 4. RADIO CONTROL
1. LH SUPPRESSOR
2. FUSE HOLDERS
3. TURNTABLE MOTOR
4. ARM TURNTABLE
5. BATTERIES
6. DEAC
7. LH. SPEED CONTROL
8. RH. SPEED CONTROL
9. Rx
10. RH SUPPRESSOR
UMBRELLA ROBOT PLATE 5. FRONT COMPARTMENT
1. EYES TURN SERVO AND MS.
2. TURNTABLE TURN SERVO AND MS.
UMBRELLA ROBOT TX DETAILS
L.H. TRACK
FORWARD
HEAD LEFT HEAD RIGHT
REVERSE
R.H. TRACK
FORWARD
HEAD LEFT HEAD RIGHT
REVERSE
ORANGE XTAL 27.095 MHz
PLATE 5.
As plate (4) but on front of shell. Two servo/microswitch units for turntable and head rotate. See circuit diagram for electrical details.
GENERAL NOTES ON PLATES.
T.X. DETAILS
Turntable and hand controls have been assigned to the left - right stick movements, as these functions are normally operated with the robot stationery.
Vertical movements of sticks control each track - forward and reverse. Sticks are self centring to 'stop'. Vertical trimmers should be used to eliminate buzz at standstill.
PLATE 1.
Reference for parts location. Note surface mounted panels at front and back covering radio-speed control - servo/microswitch units.
Batteries can be removed with turntable in position but it is far easier to charge traction batteries in situ, removing only auxiliary cell.
PLATE 2.
Shows practical arm in lowered position. Only two air rams are used on the arm, the third "arm extend" movement being achieved by mechanical linkage.
PLATE 3.
Turntable motor detail shows small model motor employed to rotate turntable. The mounting of this motor is flexible to allow the head gear to jump out of mesh with the ring in cases where the turntable is moved by means other than the motor. If the motor were to remain meshed, the gearbox stack would be damaged.
PLATE 4.
Radio control equipment is mounted on the rear of shell under cover. All units are held by metal strap with foam under. Do not overtighten this strap.
The Baby Box (“mouse droid”) Manual
This is the small black droid seen wandering the halls of the Death Star. It was originally intended to form a little train of identical droids, and in fact production photos such as the one below show such a train, but in the final movie it was used in the Chewie growling scene as a solitary droid.
This droid was simply a vacuformed shell on a commercial model racing car chassis, with some printed circuit boards glued to the side and some greeblies screwed to the top. Unfortunately the specifics of the RC car used are not known. Mouse droid researcher Steven Sloan believes that it was a Mardave internal combustion car chassis, modified to take an electric motor.
A photo from the Death Star docking bay set, showing all the mechanical robots except for the RC R2. Left: the umbrella robot. Back: the stick robot. Right: the dome robot. Front: the little train of baby box robots.
Conjecture: since most of the robots don't appear in the Death Star, perhaps Stears or someone in the production team arranged for a beauty shot of these robots to be taken at Elstree.
BABY BOX ROBOTS.
GENERAL
These robots are constructed around a standard model car chassis with conventional steering system.
The body consists of two vacuum formed 'boxes' strengthened around the open lip with timber fillets. The upper 'box' is removable for access to radio gear and drive motor.
MECHANICAL
The drive motor is a standard heavy duty model motor with gear stack mounted on the rear suspension frame (which in turn is swivel mounted to the main chassis.) The drive from motor to rear axle is by toothed belt. Only one of the rear wheels is driven.
Steering is by conventional servo via linkage and servo-saver and is proportional and self-centring.
ELECTRICAL
There are two linked systems. Radio is powered by deac, and traction by 2 6v lead acid jelly batteries via a proportional speed control. The motor should not be run from 12V direct without the speed control in circuit.
BABY BOX ROBOT PLATE 1. GENERAL
1. DRIVING WHEEL
2. TOWING HOOK
3. REMOVABLE LID
4. STEERING WHEELS
5. ON/OFF SWITCH UNDER
BABY BOX ROBOT PLATE 2. DRIVE AND STEERING MECHANISM
1. DRIVE MOTOR(UNDER 12V DRIVE BATTERY)
2. Rx
3. STEER SERVO
4. Rx DEAC
5. SPEED CONTROL
BABY BOX ROBOTS TX DETAILS
ORANGE OR BLUE
DRIVE
FORWARD
REVERSE
STEER
LEFT
RIGHT
ORANGE XTAL. 27.095 MHz
BLUE XTAL. 27.225 MHz
GENERAL NOTES ON PLATES
T.X. DETAILS
Conventional system. Left hand stick acts as self-centring throttle giving forward and reverse. Trimmer should be adjusted to prevent 'buzz' at standstill. Right hand stick controls steering. Use trimmer for 'dead straight' trim.
PLATE 1.
Fully assembled robot. Radio ON/OFF switch is slide type located under right hand side lower body box. A towing hook is attached to rear and the robot may be used to pull up to five slave boxes.
PLATE 2.
Drive and steering mechanism - location of parts. The two 6V cells have been removed to show drive motor under Rx aerial is stapled around box lip. Daily checks should be made when the robot is in use to see that front suspension and steering linkages are operating correctly. Heavy frontal blows, in particular, can sometimes 'spring' suspension and steering linkages.
The Dome Robot Manual
This is basically a smoked black hemispherical dome seen rolling along during the droid “auction” scene, being shepherded by Jawas. It has a complex interior with small disco-ball type mirrors attached to motorized discs, but the flickering light effect is barely visible in the finished movie.
All that work that went into making the robot interior, and because the smoked plastic was too dark, and the droid was filmed in a dusty desert, it just looked like a dirty black dome in the actual film.
Fun trivia fact: the periscope-type thing sticking out the top of the dome was actually a Honeywell Strobonar camera flash head.
DOME ROBOT
This is one of the group of 'tread robots.
Tread robots have 'tank-like' bases equipped with individually-driven tracks, power supplies, and radio control equipment.
The dome robot has a timber superstructure incorporating practical lighting effects and electronic dressing. Over this structure, and covering all of it except the base, is a smoked perspex dome. A slot on the top of the dome runs from front to rear, and through this slot project real and dummy aerials and a dressing light.
MECHANICAL
Motive power is provided by two permanent magnet D.C. motors having linear voltage/speed and torque/current characteristics. Each motor drives one track via a coupling and simple worm gear reduction box and drive wheel. Each motor has it's own independent speed control (forward and reverse) so that steering is achieved by normal tracked vehicle methods.
Track tension can be adjusted
ELECTRICAL
There are two electrical systems:
(1) Eight 6V lead-acid jelly cells in series parallel supplying:
(a) 24V to traction motors
(b) 2 x 12V supplies to lighting and display motors.
(2) A Deac for radio receiver circuits
DOME ROBOT PLATE 1. GENERAL
1. REAL AERIAL
2. DRESSING LIGHT
3. SLOT
4. PERSPEX DOME
DOME ROBOT PLATE 2. SUPER STRUCTURE
1. PERSPEX DOME LOCATING BLOCKS
2. MIRROR DOMES
3. ELECTRONIC 'DRESSING'
DOME ROBOT PLATE 3. BRIDGE ASSEMBLY
1. DRESSING LAMP SOCKET
2. DUMMY AERIAL
3. Rx DEAC.
4. Rx ON/OFF SWITCH
5. REAL AERIAL
6. QI LIGHT
7. MIRROR DOME
8. FLASHING BEACON
DOME ROBOT PLATE 4. RADIO CONTROL GEAR
1. SUPPRESSOR
2. Rx
3. CONNECTING BLOCK
4. DRESSING
5. SUPPRESSOR
6. SPEED CONTROLS UNDER
7. LIGHTS AND MS SERVO
8. SPEED CONTROLS UNDER
9. LIGHTS RELAY
DOME ROBOT RADIO TRANSMITTER CONTROLS
DISPLAY LIGHTS ON/OFF
LEFT TRIM
RIGHT TRIM
LEFT TRACK
FORWARD
REVERSE
RIGHT TRACK
FORWARD
REVERSE
RED XTAL 27.045 MHz
GENERAL NOTES ON PLATES
T.X. DETAILS
Each stick controls a track - the sticks are self centring so that a hands-off situation will stop the robot. Trimmers are used to zero the stick speed controls. Buzzing at standstill indicates lack of trim).
The auxiliary (2) channel is used for switching the display circuits via a servo/microswitch - relay link.
PLATE 1.
Complete dome showing slot in perspex dome and aerials etc.
PLATE 2.
Care must be taken when removing the perspex dome as its strength is considerably reduced by the slot cut along the top. It is recommended that two people lift the dome as evenly as possible, having first removed the dressing light (Plate 1).
The real and dummy aerials are flexible and it is only necessary to lift the dome some 4-5ft off the super-structure to ease these aerials through the slot.
PLATE 3.
Shows bridge assembly. Access to this bridge is possible with the dome in place, and is the obvious location for the receiver deac (2) and ON/OFF switch (4).
Also shown behind bridge is a mirror dome (7) and its illuminating QI light (6).
The flashing beacon (8) is located directly beneath bridge.
PLATE 4.
Radio control gear and auxiliary circuits. All essential control items are mounted in a recessed panel located behind one of the electronic dressing panels (see Plate 2)
Display motors and lights are switched by a relay (9) which in turn is controlled by a servo/micro switch unit (7)
All lamps are 12V and motors 6V, and thus there are 2 12V systems operating lamps in parallel and 2 motors in series in order to distribute the load as evenly as possible over the 8 cells. See circuit diagram for full details. Access to the cells is difficult and for charging purposes a standard 1/2" jack socket is installed on base of superstructure below radio gear accessable from outside even when robot is fully assembled.
Electrical connections are made at the top of radio panel using push-on automobile connectors. These also provide suitable test points.
It is recommended that whilst the robot is in transit the normally open relay contacts (9) be insulated from one another by a suitable piece of material to prevent the relay switching due to mechanical shocks.
The Stick Robot (“Treadwell”) Manual
This robot consists of a vertical arm-encrusted rod fastened to the wheeled/tracked base. It's named “Treadwell” in the novelization, and is seen with Luke during the early Tatooine desert deleted scene and hanging around the Lars homestead. The head is also shown raising and looking around inside the sandcrawler set, making its nickname as the binoculars robot very clear.
The droid reappears in Empire, when it rolls by atop the Millennium Falcon as Han and Luke bid their farewells at Echo Base.
The extended arm on the right side appears to be the same as the one installed in R2-D2 during the chessboard scene. The tip appears to be the same ice cube/pickle grabber kitchen tool.
STICK ROBOT
GENERAL
This is one of the group of "tread' robots.
Tread robots have 'tank-like' bases equipped with individually driven tracks, power supplies and radio control equipment.
The stick robot has a stick-like superstructure equipped with one practical air operated arm and claw and several dummy arms.
On top of the stick is the robots 'head' with two 'eyes' capable of turning and nodding by radio control. For identification of parts refer to Plate (1).
MECHANICAL
Motive power is provided by two permanent magnet D.C. motors having linear voltage/speed and torque/current characteristics. Each motor drives one track via a coupling and simple worm reduction box and drive wheel.
Each motor has it's own independent speed control (forward and reverse) so that steering is achieved by normal tracked vehicle methods.
Track tension can be adjusted.
ELECTRICAL
There are three electrical systems.
(1) Four x 6V lead acid jelly cells supply 24V for the traction motors.
(2) One 6V cell supplies auxiliary circuits i.e. head turn and nod.
(3) A Deac supplies the radio receiver circuits.
GENERAL NOTES ON PLATES
TX DETAILS
Each stick controls a track - the sticks are self centring so that a hands-off situation will stop the robot.
Trimmers are used to zero the stick speed controls.
(Buzzing at standstill indicates lack of trim).
PLATE 1.
See "general" for parts identification. Practical arm is shown partly raised.
PLATE 2.
Shows the mechanical arrangement of the drive motors and the battery compartment. Batteries are removable with the stick assembly in position, by sliding them out one at a time.
Air supply for operating the practical arm must be provided and connections made to couplings on the end of the battery compartment.
PLATE 3.
Shows radio control layout. Wiring has obviously been omitted for the sake of clarity. See circuit diagram for details.
PLATE 4.
Track tensioning. A reasonable tension must be maintained if the tracks are to function correctly. Tension may be adjusted in the following way:
(1) Slacken 8 bolts holding dust covers A & B.
(2) Adjust tension bolts (6) in opposite directions until desired tension is obtained. Tighten lock nuts.
(3) Tighten 8 dust cover bolts.
The sand escape vents (4) must be kept clear particularly when running on sand etc. Failure to do so places undue strain on front and rear axles and bearings.
PLATE 5
Practical arm operates from three pneumatic rams (1) (2) and (3). The claw ram is spring biassed and only has one air feed. Air feeds are colour coded.
PLATE 6.
Identifies component parts of head.
PLATE 7.
The head turn motor is housed in the upper part of the stick and drives the shaft onto which the head assembly fits.
The 'nodding' movement is obtained from a motor fitted in the head via a crank mechanism. Electrical feed to this motor is via a slip ring and brush to avoid interference when the head turn movement is required as well as the 'nod'.
The slip ring and brush should be kept clean and lubricated frequently with electrical contact lubricant.
PLATE 8.
Shows the location of the nodding drive motors and shows the eyes pivot shaft and counter balance spring. This spring is necessary as the pivot point is some distance from the centre of gravity of the eyes.
STICK ROBOT TX DETAIL
EYES UP/DOWN
LH TRACK
FORWARD
REVERSE
HEAD TURN
LEFT/RIGHT
RH. TRACK
FORWARD
REVERSE
GREEN XTAL 27.195 MHz
STICK ROBOT PLATE 1. GENERAL
1. PRACTICAL ARM
2. EYES PIVOT
3. HEAD SWIVEL
4. STICK
5. DUMMY AERIAL WITH REAL ATTACHED
6. Rx ON/OFF SWITCH
7. BATTERY COMPARTMENT
8. PNEUMATIC CONNECTIONS
9. DRIVE WHEEL
STICK ROBOT PLATE 2. COVERS AND STICK ASSEMBLY REMOVED
1. DRIVE MOTOR R.H.S.
2. AUXILIARY BATTERY
3. TRACTION BATTERIES
4. RADIO CONTROL COMPARTMENT
5. PNEUMATIC CONNECTIONS
6. DRIVE MOTOR L.H.S.
7. GEARBOXES
8. FLEXIBLE COUPLINGS
STICK ROBOT PLATE 3 RADIO CONTROL COMPARTMENT
1. Rx
2. LH SPEED CONTROL
3. RH SPEED CONTROL
4. SUPPRESSORS
5. IDLER BEARING
6. CONNECTING BLOCK FOR HEAD WIRES
7. EARTH CONNECTOR
8. HEAD TURN SERVO AND MS
9. EYES UP/DOMN SERVO AND MS
10. Rx DEAC
11. IDLER BEARING
STICK ROBOT PLATE 4 TRACK TENSION AND GUIDES
1. IDLER
2. TRACK GUIDE
3. REAR WHEEL
4. SAND ESCAPE VENTS
5. DUST COVERS A. UNDER
B. SIDE-OUTER
6. TENSION BOLTS
STICK ROBOT PLATE 5 PRACTICAL ARM
1. CLAW RAM
2. IN/OUT RAM
3. UP/DOWN RAM
4. DUMMY ARMS
STICK ROBOT - HEAD PLATE 6 GENERAL
1. 'EYES'
2. PIVOT
3. SLIP RING
4. BRUSH
STICK ROBOT PLATE 7 HEAD SWIVEL ASSEMBLY
1. PRACTICAL ARM
2. EYES UP/DOWN CRANK
3. SLIP RING
4. ELECTRICAL FEED TO SLIP RING
STICK ROBOT HEAD PLATE 8 PIVOT ASSEMBLY
1. COUNTER BALANCE SPRING
2. PIVOT SHAFT
3. EYES UP/DOWN MOTOR AND GEAR BOX
Other Appearances
The motorized chassis for one of the tread robots was reused as the base for the dorky looking robot made of two blue-painted drop tank ends seen in Mos Eisley during the landspeeder sale scene. Basically they took the base mechanism and stuck a new droid body on top.
One of the chassis was also likely reused to make the bin robot that appears briefly in the Death Star 2 scene during Return of the Jedi.
The RC R2 went through many different iterations. All the EMI Elstree electronics and mechanisms were gradually stripped out over the years, and by the time production on the Phantom Menace began at Leavesden Studios, the RC R2 was basically reduced to a hollow metal shell.
Unusual or Dated Terminology
DEAC: A rechargeable NiCad battery. The name comes from DEAC (Deutsche Edison-Akkumulatoren-Company GmbH), a now defunct German battery manufacturer. British RC users in the early 1970s used the company name as a generic term for rechargeable battery packs.
F.O.: Fibre optic.
Jelly: A rechargeable sealed lead-acid gel battery.
Perspex. Acrylic plastic. Not particularly unusual, but people outside the UK might not know that this is the UK trademark for the product sold as “plexiglas” in the US.
Plate. A picture. An antiquated term from the early days of typesetting when images were engraved onto metal plates. Up until the 1970s or so you’d sometimes see references to pictures in books as “plates”.
QI: Quartz iodine. What we now call a tungsten halogen light bulb.
Rx: Radio receiver.
Servo: Servomotor. A special type of small electric motor, controllable by a radio transmitter/receiver, that moves back and forth but which typically does not rotate.
Solenoid: a simple linear rod powered by an electromagnet. The RC R2 contained a German-built Magnet-Schulz solenoid to trigger the spring-powered leg drop mechanism.
Tx: Radio transmitter.
Xtal: Crystal. The radios used to control the robots (Futaba/Ripmax M6 units) contained interchangeable crystals that could be swapped out to change transmission frequencies.
Sources
Information about these manuals comes from Charles Lippincott blog posts, correspondence with William Shourt and Neil Anderson, pages from Steven Sloan, and auction promotional posts by Ryedale Auctioneers and Propstore. R2 manual scans courtesy Propstore.
Contact
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