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REMOTE CONTROL BY BOB YOUNG Modellers with dedication In this & the following column, we will be looking at the work of two modellers who richly deserve the above descrip­tion. For those who have complained about such things in the past, here you will find no flying sandshoes, high speed model aircraft or radio controlled machinery – just good solid R/C modelling of the most excellent kind. The first of the two is Keith Mealey, one of my oldest and most loyal customers. He specialises in R/C boats and, in particular, Murray River paddle steamers. Keith’s fleet of paddle steamers include the P.S. Adelaide, the P.S. Canberra and, for good measure, two models of the P.S. Pevensey, one in 1:16 scale and the other in a smaller scale. Just for a change I will allow Keith to tell his own story in his own matter-of-fact way. By the way, all the dimensions are Imperial, for which Keith makes no apology. The P.S. Pevensey “The first of these models is the P.S. Pevensey which is a 1:16 scale replica of this notable paddle steam- er and measures about 84 inches (2.1 metres) in length and 27 inches (686mm) across the paddleboxes. It has been scratch built using plans available from the Port of Echuca and additional measurements taken from the actual vessel. Construction commenced in 1991 and only a few details are required to complete the model. The materials used in construction were 3/8" x 7-ply timber for the hull frames and 3/32" x 3-ply for the hull sides and bottom, overlaid with 1/16" thick Obechi planks below the water-line. Obechi is also used for the superstructure. The internal keelsons are made of 3/4" x 1-1/2" square section aluminium with a 1/8" wall thickness. The engine is a twin cylinder type (built from castings — the cylinders being machined by the late Reg Wood) of 3/4" bore and 1-1/2" stroke and fitted with Stephenson reversing gear. Steam is provided by a 6" diameter 10" long copper Scotch Return boiler with Inglis modification (certificated to 100 psi). The boiler is fired by bottled propane gas. Radio control This photo shows the 1:16 scale model of the P.S. Pevensey paddle steamer. A 6-channel FM transmitter & receiver control the following functions: throttle, rudder, reversing gear, whistle, steam-operated cylin­der drain-cocks & an onboard automotive cassette player. The model is controlled by a custom-built Silvertone FM 6-channel transmitter and receiver. The functions controlled are throttle, rudder, reversing gear, whistle, steam-operated cylin­der drain-cocks and an on-board automotive cassette player. Power to the electronics system is provided through a Silvertone cus­tom-built 12V to 6V voltage regulator, connected to the same 12V, 6A.hr gel-cell battery as the cassette player. The regulator has a high current capacity to power the high-torque servos used.” One of the reasons I have chosen to present this series of articles apart August 1994  65 from the obvious very interesting content of these articles, is that each of these modellers approached me for custom built transmitters and receivers. Models such as those built by Keith require a special type of transmitter. This is in order to gain full operational advan­tage of the very spectacular models they turn out. This past development work has made it possible to present a design for a transmitter and receiver in SILICON CHIP. The receiver will be presented first, in a few months’ time. Now you may well ask, “Why present an R/C kit when there is so much cheap, high quality gear available on the market?” The answer is that apart from the obvious pleasure and knowledge obtained from building your own R/C system, one of the advantages of the system to be presented is the builtin flexibility. Our system will be capable of expansion from 2 to 32 channels, will use AM or FM, and will have many features not commonly found on commercial systems. Most importantly, it will be done with readi­ly obtainable components, thus making servicing easy. However I digress. Let us allow Keith to continue his story with an account of his second paddle steamer, the P.S. Adelaide. The P.S. Adelaide is a 1:16 scale replica of the original & measures about five feet in length. The radio control system is a JR FM 4-channel unit which operates the throttle, rudder, forward/reverse & whistle. The P.S. Adelaide “This model is a 1:16 scale replica of the P.S. Adelaide and measures about five feet in length. It has been scratch built from measurements taken from the actual vessel and has taken over 1000 hours to complete (excluding the machining of the engines). Construction commenced in 1987. The materials used in the construction of the model were; 3/8" x 7-ply timber for the hull frames, 1/8" x 3/8" Spruce planks for the hull and 1/16" Obechi planks for the superstruc­ture. The internal keelsons are of 1" x 1" square box section aluminium. This model is driven by two Stuart 10H 3/4" bore and stroke engines coupled and mounted above the boiler. They are fitted with Stephenson reversing gear. Steam is provide by a gas-fired Stuart centre-flue marine boiler (commercially built) which is certificated to 50 psi. The radio control system is a JR FM 4-channel unit which operates 66  Silicon Chip The P.S. Canberra radio control system is a commercial JR FM 5 channel radio control unit which operates the rudder, throttle, forward/reverse & a cassette player. Motor control is via a fully proportional electronic speed con­troller which incorporates a 12V to 6V voltage regulator (to power the radio receiver). the throttle, rudder, forward/reverse and whistle. The P.S. Canberra Finally, there is P.S. Canberra. “This is a 1:16 scale replica of the P.S. Canberra and measures about five feet in length. It has been scratch built from measurements taken from the actual vessel. Materials used in the construction of the model were 1/4" x 5-ply timber for the hull frames, 1/16" x 3/8" Obechi for plank­ing the hull (laid over 1/16" plywood) and 1/16" Obechi planks for the superstructure. The internal keelsons are of 1" x 1" square section aluminium. This model is driven by a 12V Marx decaperm motor with reduction gearbox, the final drive to the paddleshaft being by toothed belt. Motor control is via a Frank Brown (Maritime Model Club of NSW Inc) fully proportional electronic speed con­ troller which incorporates a 12V to 6V voltage regulator (to power the radio receiver), forward/reverse control, neutral point adjustment and maximum speed adjustment. back to the interesting conversations, the endless quest for perfection and, most of all, the enthusiasm which permeated every aspect of their lives and compare those days with the money-centred conversations of today, I am sad to the extreme. Custom radio This close-up view shows the 6-inch diameter x 10-inch long boiler in the P.S. Pevensey. Also visible in the foreground is the propane gas bottle that’s used to fire the boiler. The engine is a twin cylinder type of 3/4-inch bore & 11/2-inch stroke & is fitted with Stephenson reversing gear. The R/C system is a commercial JR FM 5-channel control unit which operates the rudder, throttle, forward/ reverse and cassette player.” The above is a bare bones description which does little justice to the exquisite workmanship that has gone into these models. From the joggling of the deck planking to the attention paid to the steam plumbing, Keith has spared no effort in his quest for excellence. Many people have great difficulty in coming to terms with this type of modelling and typical comments when viewing this superb workmanship range from “I could not spend that amount of time on a project that does not earn any money” to “I just simply would not have the patience!” What these comments reveal is a complete lack of understanding of the personality of the dedicat­ed modeller. The true, dedicated modeller is on his own Quest of the Holy Grail and in the case of modellers like Keith the Grail becomes the perfect model. Every joint in the framework or the tiniest of details become mini adventures in their own right, to be carried through in a spirit of excellence. In the end, the fact that onlookers may gasp at the finished product is only icing on the cake. The true satisfaction comes from the inside but sadly this is a spirit which is dying in our increasingly materialistic society. When I was young, there were thousands of these people and they were my heroes. They built models of all kinds of things but most of all they glowed with an internal fire fuelled by an increasingly rare commodity these days; they were content! They were great people to keep company with and I mourn their passing. When I think The transmitter for the P.S. Pevensey is a built around standard Silvertone RF (FM) & encoder modules. The unusual steering wheel was hand made & is fitted to a standard Futaba 2-channel wheel type steering unit But enough of the philosophising. Let us return to Keith’s radio. The transmitter is a built around standard Silvertone RF (FM) and encoder modules. There is nothing fancy about the RF section but the encoder features some interesting techniques. It is basically a multiplexed output type with a single tuning control to set the 1.5ms neutral. This is sent to each control pot in turn, with the extremes being the usual 1-2ms. Symmetri­cal balanced reference voltages are used which allow servo re­versing. The servo reversing is achieved by bringing the three wires from the control pot to a 3-pin header socket (positive, signal, negative). Each channel output has its own 3-pin header plug. This allows some interesting features: (1) Servo reversing is simply a matter of turning the plug through 180°. (2) Channel shuffling can be achiev­ ed by rearranging the order of the control pots on the header pins. Thus, different receivers can be used with the correct servo outputs. (3) Servo reversing is locked away inside the Tx case and is not easily switched into reverse by accident or by fiddlers. (4) The encoder PC board becomes a true module and may be re­placed easily and quickly for servicing. The photo of Keith’s Tx shows that it is fitted with an unusual steering wheel. This was hand made by Keith and is fitted to a standard Futaba 2-channel wheel type steering unit. The lever to the left of the case (throttle) is a standard single axis Silvertone stick unit, fitted with a mechanical trim lever. There are two slide controls one above the steering wheel and one on the left hand side of the case. Two toggle switches and a momen­ tary switch complete the control complement. There is one spare, unused channel built into the transmitter in case of future expansion. The receiver is a standard Silvertone FM 8-channel unit. Next month, I will describe some models by another dedSC icated enthusiast. August 1994  67