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Viodel Boats OCTOBER 1968 TWO SHILLINGS AND SIXPENCE U.S.A. & CANADA SIXTY CENTS HOBBY MAGAZINE Fleet Tender ‘Brodick’ @ Yacht R/C Mechanism @ H.M.S. London @ Monitor @ MODIEL BOYS RUDDER AND WINCH ACTUATORS FOR R/C YACHTS PART II By C. Robert Jeffries [‘ you are satisfied with the running of the assembly, remove the top plate, marking it carefully to ensure that The completed winch unit. it is assembled the same way round when reassembled. The limit switches should now be fitted, as shown in detail 15. It is important that screws should not protrude through the top. If they do they should be filed flush. Now remove the switches pending assembly of the screws and drill and pin through the top disc of the contact arm as shown in the assembly drawing. Testing The unit is now ready for its electrical tests. A circuit of connections to the relays is shown. If all is in order the rudder arm should move immediately to one side as soon as the relay is energised. As soon as the signal is removed the arm should return to the centre position. If the arm moves to one side and stays there, the leads to the motor require reversing. It may be found that the rudder arm hunts about the centre position; this is caused by over-shoot, and can be cured by increasing the gap between the two contact plates slightly. If the hunting is only slight, wait until the self- centring contacts. The contacts of the self-centring circuit are now fitted. Make the plate from thin brass sheet about 24 swg., drill all holes, but do not cut into the three components yet. Fit to the top surface of the Bakelite plate with two rivets lightly fitted to locate it while all the remaining holes are drilled. Now cut and file up to dimensions shown in detail M10. Take care to keep in the correct order. Slightly countersink all the small holes and fit with rivets made from soft copper wire. Carefully file flat and finish with fine emery cloth. The 3/32 in. gap between the two smaller plates must be fill2d with a scrap of Bakelite glued in with Araldite, Bostik, or similar. This is to prevent the contact arm shorting across both contacts. The contact arm detail 13 is made from springy brass unit is in the boat as the damping action of the rudder shouild be sufficient. Winch Unit The construction of the winch unit is almost identical, or, better, phospor bronze. The ‘dimples’ are made by so comment will only be made where there are differences. punching up with a blunt centre punch on the end grain of a block of wood. Try ona scrap piece first. Two Bakelite discs are assembled on the contact arm with 8 B.A. screws. The purpose of this is to ensure that The machining of the casting is identical, as is the method of fitting the pinions. The same 40/1 worm and wheel are used, but the final gears are 30 tooth and 90 tooth both 48 d.p. It will be found that the spindle centres are identical. The 90 tooth pinion should have a larger bush fitted as shown in detail. There is no need for alignment as in the rudder unit, so this pinion may well be pinned to the main spindle. The countershaft is identical to that used in rudder unit except that a 30 tooth 48 d.p. pinion is used instead of the 12 tooth one. The shaft centres are identical to the rudder unit. The top plate, detail 25, is fitted next. When the hole the contact arm does not make contact with the spindle. The mechanical operation of the limit switches should now be tested. The screw head forming the cam should be filed so that in addition to operating the switches it is not too big to jam if the spindle were turned too far. The total movement of the main spindle should not be more than 90 degrees, i.e. 45 degrees each way, and the clicks made by the limit switches are a sure guide that all is in order. The main construction is now complete. A nice coat of enamel on the casting before assembly is worth while. I strongly recommend that the unit is fitted with a multi-core cable and plug as diagram. Length of leads can be to requirements. The unit will be fitted either in the electronics box or under the deck, and either way a means of quick removal for servicing is very useful. A circuit diagram is given, and the use of coloured leads is also of assistance. It is now necessary to align the various parts. With the quadrant exactly central with the 12 tooth pinion, the contact arm should be exactly between the two contact plates. The rudder arm, in its central position, and the cam of the limit switches should be exactly half-way between the switches .When all is correct, tighten up ail centres are checked and all gears run free without binding the limit switches are fitted. Detail 26 shows the position in which they are fitted. The cam to operate the limit switches is geared down from the final shaft 16/1 and as the cam will move through about 180 degrees from one limit switch to the other, the final spindle should turn approximately 8 turns. This movement in conjunction with the drum to be described will give a movement of the cord, or ‘sheets’ to use a more nautical expression, sufficient to move the main boom fully from close hauled position to a position approximately at 90 degrees to the centre line of the boat. In this unit the operation is progressive, that is to say its movement may be stopped anywhere within the limits 410 OCTOBER DIMENSIONS EXCEPT ARE FOR IDENTICAL TO DETAL & & ! %e ot 9 HOLE ADDITIONAL $ SCREW 4 2. yy b | DETAIL 25, 1 DIAMETER T E Ef FIT DETAIL 19 MOTOR TYPE K.5T Ye AAKELITE P Ss NEON DETAIL 4 – 1 ae PINION eos ] ———— DETAIL 3 Y Z DP a 2! & WASHERS ASSEMBLY of its travel; the contacts and arm fitted to the rudder unit are not required. In their place is a second counter- shaft for the reduction for the limit switch cam. The gears used here are Meccano. They were chosen simply because they were suitable, and freely available at any shop selling Meccano parts. In making detail 23 the bush is pressed out of the 60 tooth pinion and this is soft soldered on to the larger bush as shown in the drawing. The 15 tooth and 60 tooth pinions on the countershaft are used as supplied but the 15 tooth pinion on the finl drive spindle must either be bored out to fit the spindle or the end of the spindle must be reduced in diameter to fit the hole in the pinion. All the Meccano pinions are fitted to the shafts with their own grub screws. The drum, detail 17, may be made in several ways. A casting in aluminium is available for machining. The part may be turned from the solid in a suitable plastic or it may be built up, prefereably in brass. Two alternative methods of keying it to the main shaft are shown. Both have been used successfully. A grub screw would be much simpler, but if fitted be sure and see that it enters into a depression in the shaft to prevent it slipping under load. The ‘sheets’ or cords just pass through a holein the top flange of the drum and are knotted to prevent movement. It will be found, however, that a better method, especially for speed in dismantling the unit, is to fit a screw as shown in the drawing and fit a loop on the end of the cord. It will be recalled that in the rudder unit the cam operates over the shortest distance between the arms of the limit switches. On this unit the reverse is the case, and the cam should operate over the greater distance. This unit is also fitted with a multi wire cable and plug. The wiring is as the diagram. There is a slight difference in wiring, done to prevent the units being plugged into the wrong socket. The unit is tested in the same way as before. If the cam operates over the wrong side of the limit switches, the leads to the motor should be reversed. If all is correct, on operation of one relay the drum will move in one direction and stop at any time the signal is removed. Operating the other relay should produce movement in the opposite direction. Methods of operation: Reeds operating Relays The commonest method of yacht control is using reeds and relays. Provided the gear is well set up and maintained it will give years of satisfactory results. The recommended circuits will be shown. The main supply should be 12 volts D.C. and may be obtained from the larger sizes of dry battery. The large type known as Lantern batteries are suitable. The use of rechargeable batteries is strongly recommended. RipMax now offers a lead acid battery of Japanese origin at around 30s. each for 6 volt 4 ampere/ hour. Two of these would be required. There are also several small accumulators available at motor scooter accessory shops. The rudder unit operates on a centre tapped supply, and gets 6 volts either positive or negative depending on direction of movement. The winch unit gets the full 12 volts. This 100 per cent overload is of no consequence. The time of operation of the sails is so short that there is no heating of the motor. It does, however, give the winch unit ample reserve of power to move the sails in the strongest winds. Methods of Operation: Proportional If required the rudder unit may be simplified by omitting the contact plates and contact arm, and replacing them by a wire wound potentiometer ‘of appropriate value. The holein the Bakelite plate will require opening out to 3/8 in. diameter. It may be found that the limit switches are better fitted by packing out with a scrap of Bakelite 1/8 in. thick. The potentiometer should be of the long spindle pattern as it also replaces the main spindle. Some potentiometers are somewhat stiff in their operation, and this can take up a lot of power from the motor. If possible choose a suitable potentiometer that is free moving, or alternatively the unit may be dismantled with care, the sticky grease removed, and the spindle eased with a smooth file. Take care on reassembly that no traces of filings or dirt are left where they might give rise to doubtful operation. The wiring when using a potentiometer is as shown except the slider should go to pin 5 and the ends of the windings to pins 4 and 6. When using relayless circuits the O.C. 35 transistor is quite suitable to carry the motor currents even without a 411 DETAIL 25/26 DETAIL 3/a” RD HD RASS SCREWS 7 , : 5 sts 40 TOOTH 64 DP [ ie Rate ASSE te Ge tanaiee (We Ne = NN | z a, ~ | ; ACTUATOR & WASHER [ TO TRS i REAM Ya” DIA X ‘/a” BRASS Se Ye mk \WINCH 4BA DETAIL 17— -r Oras ae } ASSEMBLY OF 1968 23 MODEL BOATS r rer i aed 7 cea i | ait AR \ 480 GRUB SCREW Ba CONTACT PLATES DETAIL 10 SPoETAIL9 ‘ie‘ 2HOLES row | 6 Ke | Le — ue tes 4 the REAM Va”DIA =F a = Sie itp rae a | & i DETAIL 9. Ys BAKELITE i Reo =a ut 4 HOLES 6BA CLEARING 2 | y oars) \ | HOLE Ye DIA 3 ees fA XQ TEXT = ‘het | ‘DIMPLES’ 4 7 f | Geass Me = & WASHERS ¥ | S eos BRAS: “MICRO SWITCHES (LEVER TYPE) TE T CAM OPERATES THiS SIDE OF LEVERS “OP Al PL RUSBER) 37a” DETAIL 3 PHOSPOR BRONZE i. ce > 4 484 GRUB SCREW Ve DIA Ye es DETAIL 10. e Us BRASS | 1 5 | ae ar aces — DETAIL II t : = = =) : r s “J i 245WG.- LOFF | 2HOLES | 7,,- BBA CLEAR, [Me { Pat w Maz pissed COMPONENTS PINNED TO SHAFT MOM 40T 64DP BRONZE 4″ 2 WHEEL 4 | C a – ALL te 4 | 2 DETAIL7 il —I2T 48DP DETAIL 12. ne PINION pea 4 COUNTERSHAFT ASSEMBLY ~ REAM ‘4” 4 , D STEEL Veo* ‘ “6 BA BRASS SCREW FILED DOWN FORM CAM TO may BAKELITE ) i pe | 1OFF 2 HOLES |e ye +! TAP 8 BA 344″ ———+ Is La DETAIL (ey | TAP 4BA x Ya” a Ce) DETAIL SS we ere DEEP 18 BRA: ~ |? t cMINUM NUM 0 OR ALUMINIUM OR PLASTIC TURN TO FIT 15 TOOTH } heat shunt. The writer’s present equipment retains relays for the winch, but uses relayless for the rudder. The relayless rudder unit gives instant response, and is very helpful in getting the boat out of tight corners when racing. One point concerning any equipment. It should be properly fused with fuses of suitable rating, also when individual requirements. The writer’s preference is for all the gear to go into one really waterproof box. This has the advantage that if the boat is left at the clubhouse or in the garden shed the expensive equipment may be kept in the warm and dry. The motors fitted to these units are multi pole and are fairly free from electrical interference. If any sign of interference is noticed a capacitor of 0.1 mfd should be connected directly across the motor terminals. Anywhere else can sometimes increase the troubles. using a centre tapped supply it is necessary to switch two leads, and these should be the centre tap and the ee lead. A double pole single throw switch should e used. Parts List for Winch Unit Frame casting. Aluminium 1 off C. R. Jeffries, Winch Drum casting, Aluminium 1 off | 17 Colmere GarSpecial Motor 6 volt type K 5 T dens, Highcliffe 1 off on Sea, Hants. 40/1 Worm & Wheel 64 d.p. 1 pair Bond Ltd., 357 30 tooth Brass pinion, 48 d.p. 1 off / Euston Road, 90 tooth Brass pinion 48 d.p. 1 off London, N.W.1 15 tooth Meccano pinion part No. Any toy shop 26C 2 off selling Meccano 60 tooth Meccano pinions part No. | parts 27D 2 off Limit switches 2 off ‘Radiospares’ SiC ~~. Recommended Installation The installation of these units and their associated Ee ei OOS electronic equipment and batteries is left to individual choice. The units being of one hole fixing are easily installed under the deck or in a box that contains all the equipment. The length of leads on the units is dictated by The completed rudder and winch units installed in the radio box. Connecting wire 6 different colours 9 pin Plug type B.9.A. 1 off 9 pin Valveholder type B.9.A 1 off — { Micro switches / (Lever type) through any radio shop 6 B.A. by 3/8 in. Rd. Hd. Brass Screws 8 off Local Iron6 B.A. by 4 in. Rd. Hd. Brass mongers or screws 4 off 6 B.A. Brass Washers 12 off shop 1/8 in. sheet Bakelite 1 piece Sundry brass Rod & Sheet as required On the drawing and parts list included in last month’s article, the following information was unfortunately excluded. We apologise for any inconvenience caused to readers for these omissions. On the drawing of the frame casting, the radius from the main spindle centre to the countershaft is 14 in. In the parts list, the reference to the 40/1 worm and wheel should also have included the d.p. of the wheel, which is 64. 412 OCTOBER HE Mongolia was built in 1923 by Sir Armstrong Whitworth and Co. Ltd., for the P. & O. service to Australia. Quite different in appearance, but internally similar to earlier ships, it is said that her unusual profile caused her to be unpopular. It is always difficult to establish the truth of these stories, but it is a fact that her sister ship, the Moldavia, had a second funnel fitted. The results of this operation seem to be unknown. The Mongolia continued in service until 1938 when she was purchased by the New Zealand Shipping Co. Ltd., renamed Rimutaka, and placed on the New Zealand run via Panama. In 1950 this vessel did a year on the North Atlantic under new ownership. She was then purchased by Readers Write MARBLEHEAD SAILS Dear Sir, The current argument about the Marblehead 80 per cent. jib hoist rule seem to hinge on the definitions of ‘suit’ and ‘rig’. At the present time, model yachts seem to be at a major stage in the old process of passing from the model boats concept to one of racing machinery, and designers are looking increasingly hard at the rule books to take advantage of every letter. Some older rules cannot stand such scrutiny and hence the 10 rater rule has had to be revised. The M rule is now giving way at the joints. It is of no use appealing to the spirit of a rule. The rule must be final. This is easy enough; once one had grasped the spirit of arruleit can always be putinto words with a little clear thinking. To those who cry ‘pedantic’, | would point out that it is by little levers and gears that a great ship is held back on the launching slip; the little things are important. Now there are two points at issue, and the way they interact. The first is alternative rigs. One policy would be to ban them. Other classes manage without, and it would save expense, sailmaking, and the need to arrive an hour early for races to change them about. It would also save the complication of rule and measurement, for if one must have alternative rigs then one must have adequate rules to cover them, and the present rules are not adequate. On the other hand they add interest, and it is nice to think that one is making the most efficient use of one’s sail area. The other point is the 80 per cent rule. Again, other classes do without. A higher jib is more efficient but may make the boat less docile. To maintain this rule for reduced area suits would mean cluttering the mast with jib anchoring points. Now a ‘suit’ is surely a pair of sails usually used together. A Marblehead may have any number of suits of all shapes and areas within the 800 sq. in. If it had a thousand suits, only one of them is the largest. Rule V says that the jib hoist of this suit must not exceed 80 per cent of the main. As the rule stands, one could make this suit of tissue paper and produce it on demand. All the other suits could have masthead jibs, even though they may be only 0.01 sq. ins. smaller in area. Mr. Shepherd takes a different view. He seems to divide his suits into families, each family headed by, and taking its name from, a top (800 sq. in.) suit lettered A, B, C etc., as appearing on the certificate (he mentions a second suit of the B rig). Maybe some the Incres Nassau Line and set to work cruising from New York to the Bahamas under the name of Nassau. I have been unable to trace her history since that time, but I understand that she has been allocated to another company. One very interesting fact about this ship is that during her 40 years and more of service her appearance has hardly changed. The promenade deck is now partially glassed-in and one mast behind the navigating bridge serves in place of the original two, but this old ship is still very much the old Mongolia despite the white hull and the yellow and blue funnel of the Incres Nassau Line. families consist of a top suit only. He calls each family a rig. He interprets the 80 per cent rule as applying to the largest suit of each family or rig. He also implies that sails from different families should not be mixed. This is all in the spirit of the rule, but the rule says nothing. It should, and so needs revision. Except for top suits, this division into families is artificial One cannot go by aspect ratio since hardly any two suits of a yacht have the same A.R. | would suggest something on these lines: With all the declared suits before him in Pile 1, the measurer shall put aside into Pile 2 any suit smaller in a// dimensions than any one other suit. The jibs and mains in pile 2 then lose their original pairing and the measurer may pick out from pile 2 any new pair which fails the original qualification for pile 2 and restore them to pile 1 (this is to prevent any possible combination exceeding the basic 800 sq. in.) ‘Each suitin pile 1 is then measured and both sails marked indelibly with a letter of the alphabet. No jib hoist of a measured suit shall exceed 80 per cent of the main. The main and jib outhauls, and the hoists of each measured suit shall be marked on the mast and booms with the appropriate letter. If a lettered sail is being used, then the sail with it (which may or may not be lettered) shall not be hauled beyond the marks bearing the same letter as the former sail. Note that it is still the sails which are measured; the marks are to prevent stealing area or hoist by clever combinations. | cannot see a loophole in this method, but perhaps someone else can. It sounds complex in full operation, but it would only operate fully if someone attempted to steal area orjib hoist, which they would not because of the presence of this rule. Most yachts would go straight through with three measured suits and two smaller ones. Mitcham, Surrey R. A. Phipps. SHIP PRESERVATION Dear Sir, There are at present still in service round the coasts of the United Kingdom very few passenger carrying 1968 ships with steam reciprocating engines propelling them either by means of paddle wheels or screws. These are of great technical interest and of historical significance for illustrating the development of the steamship. Because these ships are now considered by some owners to be no longer economic to run, they are being withdrawn from service and sent to the breakers at an ever increasing there is only one paddle steamer still in service; she is British Rail’s Ryde, which operates on the Portsmouth — Isle of Wight run, and which may well be taken out of service by the end of this year. The veteran paddle steamer Duke of Devonshire, built in 1896, has been laid up on the River Dart for over a year awaiting a buyer, and may go to the breakers any time now, unless there is a last minute reprieve for her. The situation regarding screw driven steamers with reciprocating engines is not much better. So far as | know, there are now only four such vessels still in service; two of these are tug tenders operating at Blyth and Manchester respectively, the latter dating from 1903. The remaining two steamers are Jersey Line’s La Duchess de Normandie, operating between the Channel Islands and French ports, and the Port of London Authority’s V.I.P. yacht St. Katherine. There may well be other such ships of which | am not at present aware. It is now vital that some urgent action be taken to save for posterity what is part of Britain’s maritime heritage. A group of steamship enthusiasts have been working together recently to investigate the possibility of forming an organisation which would purchase any steam driven vessel or vessels of particular historical or technical interest, and operate the same where practicable from any suitable place in the United Kingdom. The proposed organisation would be in the form of an Industrial and Provident Society, in which shares are issued to members. A draft of the rules for the proposed society has been drawn up, and has been approved by the Registrar of Friendly Societies and the Registrar of British Shipping, thus enabling it to own a British ship. The next stage now is to form the society, and to get it registered, and for this purpose a special meeting will be held within the next few weeks. Anyone who is interested and keen to achieve the formation of the society and the fulfilment of its aims is cordially invited to write to Mr. R. A. Castle, 8 High Stile, Dunmow, Essex. Broadstairs, Kent. Patrick Taylor A.R.1.B.A. ENTERPRISE Dear Sir, Could, through your columns, appeal for anything connected with the ships named Enterprise. Our unit is T. S. Enterprise after the cruiser of that name, we have a history of H.M. ships of that name, and we would also like to build a model ofthe various ships, including the U.S.S. Enterprise and the Enterprise Dinghy. rate. This state of affairs has now reached alarming proportions. On the South Coast 431 J. Garsides (Lt. R.M.R.) 135 Hillfoot Road, Airdrie, Scotland.
