Model Maker: Volume 5, Issue 56 – July 1955

“Royal Falcon” Electric Powered Paddle Steamer: “Dat Prince” Japanese Model Car for If cc.: G. H. Davis’ “U.S.S. Newport News”: Yacht Championship: Monorailway: Unit: Ten-Rater National ‘‘Monosonic” Progressive Rudder Short Spurs: Guying with Vane p Steering: Goldplated 72 L7 Model Car Chassis cn SS MOEN MAKER then is to disassemble the motor completely and clean off brushes and commutator thoroughly. It needs very little oil getting through on to the’ commutaor to ruin the running characteristics completely. Removing the bearings themselves to replace or renovate the races which would necessitate reduction gearing for use with a marine screw. Small accumulators could be used to advantage for lower speed operation, although these would represent an appreciable initial cost to give the required 12 volts. Actually the motor will continue to run satisfactorily down to 6 volts, but with corresponding loss of power, of course. appears a most tricky job and so the real answer appears to be to check the bearings at the time of purchase. The power characteristics are rather different from those normally expected of a shunt wound motor. Usually for motors of this type the The main body of the unit is formed by the field coil laminations, the two end_ plates being bakelite mouldings, each attached with four screws. Disassembly is relatively easy (by removing these screws), although it may be necessary to tap the armature spindle from the contact end to remeve the far end plate and withdraw the armature. The three main leads to the terminal strip have enough slack to allow this end plate to be levered open, but only just. torque curve is much flatter—almost parallel over a substantial part of the speed range, in fact—and with no marked peak when stalled. The high initial torque can be an advantage for starting under load and also combating such “service” conditions as a fouled propeller, etc. However, when heavily loaded the windings do tend to overheat and prolonged operation under such conditions should be avoided. For getting the best out of the motor the “ideal” operating speed would appear to be between 2,000 and 2,500r.p.m., when Total weight of the motor is 1 lb. 12 0z. The only provision for mounting is four holes in the top tapped to take a 4 BA thread. Two similar holes on the bottom are tapped to take 6 BA. However, since the body is square, fastening down should be a simple matter, using metal straps screwed down to a suitable base plate of metal or ply. This particular motor would seem current demand is relatively low and both the overall and mechanical efficiencies near their peak. There is ample torque available at these speeds for driving, which torque can, ef course, be multiplied by using reduction. gearing—pro rata if gearing losses are neglected. an excellent power plant for model boats of hull size 36in., upwards—or for radio controlled boats of 30in., up. The only disadvantage from the latter point of view is the nonreversibility. which could only be overcome by modifying the internal wiring, or with a mechanical device to utilise each end of the drive spindle alternately. To check the condition of the brushes of similar motors we would suggest measuring r.p.m. and current consumed and compare with the test figures. Higher values of current for the same r.p.m. would indicate excessive contact resistance and either new brushes or, more probably, a period of running in to bed the brushes down properly. All told, this seems To keep the current consumption down to a particularly useful motor for the larger sizes reasonable figures it would seem advisable to run the motor under load at about 2,000 r.p.m., of models and something current “surplus” prices. of a bargain at iat —- 10-RATER CHAMPIONSHIPS (continued from p. 384) requiring a further resail. On this second attempt Judith was in the lead and the boats again touched; on the third -attempt with nothing between the boats they touched again! Not: until the fourth attempt was a decision reached; Tornado led the way home after two rapid retrims within inches of the line, creeping across with Judith overhauling her, though not quite soon enough. It was a splendid race with a very friendly atmosphere and some very interesting boats 382 present. Most radical of the designs was Triplane II which, however, was at a disadv antage in the prevailing light airs. Two visitors from Ireland participated, and Blue Nymph’s fourth place, after a sail-off with Flora, was very popular. The oldest boat in the race, Isis (1953 winner), well deserved her third place. The Birkenhead club is to be congratulated (a) for the excellent organisation (b) for filling the first three places in the results and (c) for having so willing a team of charming ladies to sustain the inner yachtsman! PE YS NESS 5 MODEL MAKER VISITS BIRKENHEAD FOR THE 1955 BRITISH & OPEN 10-RATER CHAMPIONSHIPS Heading picture shows the boathouse corner of the water with, clockwise, “Tris”, “Flora”, “Judith”, “Estrellita”, and “Tornado” after, or on the point of, arrival. IRKENHEAD, the site of the 1955 10rater Championships, had its full share of the bright sunshine which favoured the whole country over the Whitsun holiday. The fleet of 17 boats assembled for the event (fortunately all by car) took full advantage of the excellent weather, although a fluky wind kept the skippers on their toes. Saturday started off a little on the dull side, with a S.E. wind blowing chiefly along the diagonal of the lake. “Chiefly” because a variation of practically five points was likely to occur without warning and at any moment! At 11 o’clock sharp the O.0.D., Mr. A. R. Andrew of Birkenhead, called the skippers together for a brief address, and at 11.05 the first pair were away. With three complete days in which to sail the 17 boats, it was decided to sail two full rounds, the results to be taken at the end of the first round if, for any reason, it was found The tense climax of the race is shown in the upper left photograph below as “Tornado” just makes the line with “Judith” speeding down in the fourth resail. Lower picture shows the Commodore’s wife, vivacious Kathleen Priest, presenting the trophy and a champion’s salutation to the winner, who was, of course, Dick Priest, Birkenhead’s Commodore! Right hand picture shows “Tornado” drawing well on the run with one of the Irish boats, “Blue Nymph”, some lengths behind i impossible to complete the second. With a reasonable weight to the breeze most competitors were happy enough on the first day and when sailing ceased, Tornado had estab- lished a slight lead with 32 points against Suroni’s 30, with Isis, Flora, Judith and Laurein jostling the leaders with 27 points apiece. Sunday dawned bright and sunny with the same wind direction, and a breeze slightly less powerful, but much more capricious. The last few heats of the first round saw no major alterations in the positions, except that some of the heavier weather boats were in trouble and conceded points. At the close of the round, Tornado had retained her lead with Flora in second place and Judith lying third. A sail-off, just in case, secured fourth place at this stage for Flair from Suroni. Minor changes continued to take place during the early part of round 2, and at one time Flora had established a lead of several points. However, with the wind becoming even more fluky, a considerable change in positions began to take place, and the condition arose where many leading boats sailed into the boathouse corner of the pond and lost the wind, while their opponents, making an extra tack, sailed through in the opposite corner full and by all the way. Monday saw a repeat of these conditions and trim became a toss-up, with the wind shifting within seconds so that even the rigging of the spinnaker became a problem. There were some very close boards and some extremely lucky ones, but in general the heavy weather boats lost ground rapidly and some just didn’t get going at all. The second round closed with Tornado still in the lead, and Judith three points behind, but with a board in each direction to resail against Minerva, which had required repairs to her gear in an earlier heat. Somewhat to the surprise of the spectators Minerva sailed straight down the water on the run, while Judith required a retrim and lost the two points. She comfortably picked up three on the windward board, which gave a tie for first place. This was sailed off in an air of mounting tension, but, with Tornado in the lead, the boats touched, (Continued on page 382) Top photographs from /eft to right: (1) “Judith”, to John Lewis’ “MODEL MAKER” “Halceyon” design, was a deserving second. (2) The collapsed spinnaker of “Tornado” with “Estrellita’s” still full shows the fickle wind conditions. (3) “Flair” sails into unruffled water with “Laurein” still getting a fair breeze a few yards further over. (4) “Francis” leads “Laurein” on the beat. (5) It was no weather for “Triplane” although she has a comfortable lead over “Minerva” in this board. (6) “Tornado” takes advantage of ashort spell of breeze with “Estrellita” just appearing in the picture. Oppcsite page, centre left, Arthur Levison’s “Suroni” suffered from the too-light wind; here seen off on the run with “Vectis”. bottom left, the two top boats, “Tornado” and “Judith”, gently gather way with spinnakers just filled. Regd. No. I 2 3 4 5 6 7 7 9 10 Il 12 13 14 15 16 17 | | | | | 1328 1325 781 1407 1205 1224 979 1268 1338 1416 1377 1408 1324 1413 1397 1412 895 YACHT SKIPPER | Tornado B. H. Priest .. | Judith E.M.Butterworth Isis … | W. H. Jones | Blue Nymph L. Paton … .. Flora .. E.J.Blackshaw … | Suroni … A. Levison Estrellita …. J. S. Thomas Vectis K. Jones Francis… H. Atkinson Triplane Il J. H. Snowden Laurein D. Watts Flair J. Anderton Pampero J. Lace seat Iris… K. Roberts … Cordelia P. T. Mustill .. Minerva Il A. Johnston | Recovery … J. Sills CLUB Birkenhead… Birkenhead… Birkenhead … Ulster … | Nth.Liverpool Guildford Bristol ; Morecambe Bradford Sheffield Morecambe M.Y.S.A. Ulster Morecambe Nth.Liverpool Nth. Liverpool Bournville …. TORNADO L.O.A. 74.0 JUDITH _….. 69.0 ISIS a 68.0 L.W.L.55.0 52. 53.0 DESIGNER Priest Lewis Simonsen BUILDER bee’ Priest ae Butterworth K. Jones R. Priest Paton Priest Andrews Littlejohn Levison Seabrooke Seabrooke … ase haw K. Jones/Boardman Shaw .. Atkinson _… Waddington Waddington Simonsen Andrews Wake Wake Priest ; Lace Bains … Evans Mustill … Mustill ae ‘a Lewis(modified) Johnston _… a2 Broscomb Broscomb … ein .. 32 27 27 24 27 30 18 19 15 25 27 25 17 18 16 9 | Beam 10.5 11.9 11.0 Disp. 25.0 lbs. 30.6 24.25 Yee bad Day Round Day 57 51 48 47 53 49 32 46 36 40 42 49 32 39 30 16 13 76 77 69 63 67 69 58 60 51 62 67 66 47 48 37 23 20 Total 108 108 106 96 96 91 85 85 8! 719 78 76 71 68 64 38 30 S.A. 1065 1153 —_ Below, top row: Left, “Pampero” and “Cordelia” make a most attractive picture against the sun. Centre: “Tornado” shows “Suroni” the way. Right: “Estrellita” and “Iris” seem a little undecided on their courses. Bottom row: left, “Tornado” once again, this time leading from “Laurein”. Centre: converging courses such as those of “Vectis” and “Judith” caused many resails. Right; “Isis” pulling away from “Flora”. Small boat above “Flora” is “Recovery”. mT ll moo MAKER SN) NeW END SE DIRECTION EXPERT & NOVICE SKIPPERS WILL ENJOY THIS TWO-PART ARTICLE BY WITHOU A. WILCOCK ON THE SECRETS OF. GUYING WITH VANE STEERING i ae me i Gs recent series of articles by Mr. H. E. Andrews were interesting and encouraging. The vane has now been with us long enough for more to be written by more people. The present article is on that branch of its use which holds more personal secrets than any Other. It is intended, therefore, not only to be informative, but also provocative. It may be as well to define for the uninitiated what is meant by “GUYING”. The term is very loosely used in the sport, the word GYE being used as both a verb “to gye”, and as a noun, have you fitted “the GYE?” A boat is said to have gyed when it intentionally changes tack when sailing to windward. If it does this shortly after leaving the bank, it is a “short gye”, and if after a considerable distance, a long, or lazy gye. Fig 1 illustrates the conditions “a” is a short gye, and “b” a long or lazy gye. Fig. 1 also illustrates how important this manoeuvre is to the racing man, since in coming ashore at point “c” quite near the finishing line, changing tack alone would mean sailing almost the width of the lake to cross the finishing line, whereas with a short gye, the line can be quickly crossed. One finds the facility less frequently provided by the non-racing lone sailor, but to him (or her) it can be equally as useful. The advantage here is that when the wind is in an awkward. position for single – handed sailing, such as straight down the pond or even as far round as is shown in Fig. 1, the full length of the lake can be sailed on long and short gyes from one bank. The man- oeuvre intrigues the onlooker, and reliable gying gives great satisfaction to the skipper. It is not generally appreciated that there are two basic designs of good vane gears the world over, and the majority of gears are merely variations on these two. The two basic types are both called after well-known American skippers, Fisher and Ballantyne. This arises from the fact that initial vane gear development took place in the early days of the 1939-45 war period when model yachting had virtually ceased in this country. It is also no deubt in part due to the more conservative outlook of British Model Yachtsmen! The basic Fisher type is illustrated in Fig. 2, where the tack and tack motion is by a pin and slot linkage between the feather and counterweight movements, the pin being on the counterweight assembly and the slot on the feather assembly. Fig. 3 illustrates the basic pattern of the Ballantyne gear where the linkage on tack changeover is by toothed gears. In the October, 1952, MopEL MAKER the author purposely reversed the pin and slot arrangement of the Fisher type gear, and with this reversal the Fisher gear behaves in its operation more as a Ballantyne as will be apparent from what follows. Turning now to the body of the subject, let me first dispose of the simplest gying operation, which is really outside the present study but should be mentioned. It is simply illustrated in Fig. 4. The wind is at an angle of between 40 and 45 degrees to fhe axis of the pond and possibly shifting slightly. Starting from the starting buoy with the vane 394 FOES (either type) fixed and set to point the boat as high as she will comfortably sail, say 42.5 degrees, the boat comes ashore five yards from the finishing line, the boat is turned by pole or hand on to the other tack, since the gear is in the fixed position maximum helm is given, and she will come round on to the original tack probably within a boat length, but with the wind in the direction that it is, the course taken will allow the boat to cross the line with one or two such manoeuvres. Gying in this. manner is only suitable for occasion when the course can all but sailed on one leg or a slight shift of wind forced the boat off course when nearing the be has the line. The actions we are really concerned with are those in which the tack and tack motion of the gear is in use, i.e., unlocked and the main body of the gear is in line with the arm to the tiller. On one tack, say the port tack (wind on the port side), the vane feather and counterweight are on the starboard side and when we gye we change to the other tack, wind on the starboard side, and vane and counterweight on the port side. Before we discuss how this is achieved quickly or slowly, we must draw attention to a very great fundamental difference between the two basic types of gear previously mentioned. The best course a model yacht will make to windward lies between 40 and 45 it may point at about 30 degrees wind but with the leeway made will a course of 40 to 45 degrees. The WIND degrees ; into the complete apparent DIRECTION MES wo Fig, 4 Pas ‘ ) 1 1 ! ASS wind is therefore of this order, and the tack and tack setting must be about this, say 42.5 degrees. At this angle the Fisher type of gear locks by the counterweight being held by the heel of the boat and gravity. Wind pressure on either side of the feather is communicated to the rudder positively by the locking action Fig. 5. For this reason the feather can be as light as is adequate to give mechanical strength, and the counterweight is correspondingly light. To unlock it to change tack, the counterweight has to moved over first and the feather follow. be in changing tack at the side of the lake by pole or hand the changed heel of the boat to the wind on the opposite side does this. How to do it in gying will be discussed after stating the operating conditiens of the Ballantyue gear. The basic Ballantyne gear obtains its tack motion by toothed gears, and there is no locking action. Control of the rudder is determined by the gravitational force on the feather and counterweight when the boat 1s heeled. It is possible with this type of gear to have the feather and consequently the counterweight too light so that the water pressure on the rudder against which the vane gear is trying to operate is too great and the tack motion on the gear will “give” rather than operate the rudder. For a given size of rudder there is, therefore, a mininaum weight of feather and counterweight irrespective of the actual size of the feather. [It is important, therefore, when sailing with this type of gear to observe whether there is a tendency for the tack motion to “give” rather than actuate the rudder. If so improvement can be obtained by increasing the weight of the feather either by increasing its size or using slightly heavier material. The counterweight must also be increased correspondingly to preserve balance. It will be clear now that to gye requires that means has to be found to changeover the tack mechanism of the vane at the appropriate ‘ moment |eda PRESSURE — a moment, so far as possible, to be the decided by skipper. EITHER WAY FROM WIND ON FEATHER DOES NOT MOVE PININ SLOT. (To be Continued) | cc rR a oo eet STARTING ON THE RIGHT TACK AN INTRODUCTION TO MODEL YACHT RACING PART TWO—SAILS: THE DRIVING POWER (Conclud ed) BY D. A. MACDONALD Left: Fig. 9: A Class Model “ Sabre” (Figs. VIITA and VIIIB), the longfooted jib, the strictly triangular, flat mainsail (no elliptical roach and no camber), and see how the sails are set as twin cone sections , overlapping slightly in the case of the Dragon . Note also how that past-master in sailing matters, ‘Pek present reaction to the gaff difficulty 1s to make the mainsail triangular. In order to preserve the conical shape for the sailplan, we therefore divide the basic cone sector DEF along the line EG (Fig. VIIA). This gives us a Bermudan sloop, with a masthead jib (Fig. VIIB), a rig often used in mann ed yachts, particularly in the ocean racing classes . In the model world, the rating rules would prevent this in the “A” and “MTM” classes, but we have found that in the 10-rate r, and even more almost at so in the the 36 in. masthead class, is fairly common Note also the large among successful yachts. a jibstay proportion of jib to mainsail, again very much in line with the trend in recent succes sful designs. A final variation on the theme is shown in Fig. VII[C—the resurrection of the curved mast theory, expounded some years ago, showing that this rig fits into the picture as an attempt to preserve the conical form, with a limited height of jibstay. For a practical corroboration of the conical sail principle, we have only to look at any well-trimmed yachts sailing a reach ing or windward course. Fig VIII gives some typical examples. Note on the Nicholson yacht “Phoenix II” and the champion Drago n class ounces Fox, trims his “Flying 25” per square yard, but up to 34 ounce material has been used for large A-class sails and for storm canvas for most classes. Union Silk has a very close weave, so that it is Virtually “air-tight”. The wind striking the sail therefore does not pass through it, but is deflected along the surface of the sail. The cloth has a fairly smooth texture, which makes for efficiency, and it does not shrink or stretch to a serious extent. Sails of this materia l can therefore be relied upon to retain their initial shape and size fairly well. The cloth, is how- ever, 398 Uffa (Fig. VIIIC), and finally observe the beautifully conical trim of “ Bluebottle ” (Fig. VIUD). The A-class model in Fig. IX, despite its very high aspect ratio sails, is none the less using them in a similar way, to obvious good effect, aided by a heel to a nice angle for the prevailing light breeze. From the foregoing brief study of sails past and present, we can form a basic idea of how sails are designed and used to best effect in racing. In a later article I hope to go into the question of trimming sails in greater detail, and meanwhile, let us consider how sails are to be made, so that they can be set to give their required performance, and relied upon to retain their efficiency over a long period. This involves, firstly, a study of materia ls, and secondly, of techniques for using these materials correctly. The most commonly used material for model yacht sails has for many years been a high-grade Egyptian cotton (often referred to as Union Silk)—the same cloth as that used for light spinnakers on full-siz e craft. Only the very best quality is satisfactory, and this, when obtainable, is nowadays very expensive. The optimum weight is about 2-3 capable of absorbing moisture, and in JULY, wet weather it becomes heavy and lifeless: after a wetting, great care has to be taken to dry the sail in such a way that it does not go out of shape. It shrinks slightly when wet, and the trim of a yacht is therefore subject to considerable variation during showery weather. The success of a sail made with this material is also largely dependent on the tape used for binding the luff and taping the foot. Linen tape of the highest quality is the best to use; the tape has to take the pull of the halkiards and outhauls and so protect the sailcloth from being stretched. The amount of ultimate stretch of the tape must be known, and in the sewing process, the sail has to be fed into the tape in such a way that when the latter has reached its ultimate extension, the sailcloth is just taut, and the sail is setting in its correct shape. While the tape on a new sail is being stretched, the sail must be used with great care, and only in fine weather. It will not attain anything like its full efficiency until the stretching process is virtually complete. When the sail is perfectly stretched, the peak of performance is reached. Unless the taping has been carried out absolutely correctly, and the materials used are perfect, the sail will then begin to deteriorate; it is thus 100 per cent efficient 1955 yachtsmen have their sails made by professionais whose chances of maintaining regular supplies of the same material are much better. Several alternatives to Union Siik have been tried out from time to time. The first really successful one was “XL” cloth, which was a treated cotton fabric, substantially waterproof, with a smooth surface and a metallic character which gave rise to the nickname “tin sails”. Fig 10 LUFF (SLIGHT LUFF HOLLOW) / (SLIGHT ay 4 4 This material is, however, no SiBRn? ] 5 tna THIS LINE IS SELVEDGE for only one brief moment in its life. For- tunately, deterioration sufficient to be noticed does not set in for a very long time in a good cotton sail—in TAPE LINE fact, many sails made by masters of the art, such as W. J. Daniels and the late Chas. Drown, before the war are still giving perfect service. Post-war materials, have, however, proved to be, in general, of lower quality, and continuity of supplies of any one material is uncertain. It is thus a common practice for a sailmaker to get used to the characteristics of his materials only in time to have the source of supply dry up, leaving him to start again learning how to use a new material. This makes sailmaking ‘by the amateur a risky business, and most model SKIRT a longer obtainable, and treatment of cotton with varnish and similar substances has not proved very effective. Having had considerable difficulty in getting consistent results with sail materials on the post-war market, I spent some time investigating various synthetic materials, to find one suitable for model sails. The outcome of my search was varnishimpregnated Terylene, with the first available sample of which I made sails for my A-class HAA nUJYIMsu.aOAzY0NBIt}Od}oYsOmsujOqsATpooyoyAIeTRuI4‘njEU]eyy)g)MYx]pqUi0)pSuPd)si[NcnDJAJ1l1jfepq&gNAe9a0r49d‘Wg,}Tj(a}tioJp9V‘Qor“IJRGrSyS0YyNxB}}yUMO,Gsa-NU[rOenBu07I9N>Ju’]Mdm]W}u&—YTp‘n,uD]plJWePY4y|eqEd}[TPTlfIr,onesJJFsAosNoSsDoS[rtUqq9tuieydliwj[M‘OeoUjqSPYOypslp4u¢I“~I}BJ{OpnO1‘J‘R}tIupQ)ePS[9US2d[Y4JUnvMYa1BBqIJsii]lAd09YUpMSg]OyqN-1SosYAAaprTeoAsjijaur]IUieUeRNy,.,eqDyBnrLS]JWls® o‘o3p‘a4yqud.)neeyAMj9sImpaymujwsAwRtzDrYI‘UrpoaSluqnX])nxN,i[3JeTOd“P“A}os,1}iSVTjDdB[rtu,BR0IjiMWJ‘Ye\u-OWnJ]pUydlptdY0Bpv}POdrIuy9}eAlzesMIi[3i‘ntqj\auoy]4)‘“oNTjnmso“,mrT[jySqds‘gVYluUSeRnTexJ}OPI9l)g2Lp4rIy0eWMpu}D 0.)HU,3/0.3 soyu}on“eSolrqYqyndo]“3,”eY)oR,eT[EJopoy}Su[rrfetsegUe(.r)1J1eI0Q(qAiqf oy} “WLS oY],YN] Jo y} [resul plmoys 9q S[WU“Ke7OloIBPMdTy6sY,uH “‘SJUe0pIDRT4OM}dWAoutjsyilqm“Y0UIrendT sApyo0NJSujOUReYWIEd dsJSI‘Oo&RYD}[yt@Ne pAo‘mjJnsyqdOr[e}0 OYJ[SAsIj&T0uN)]eqMy A[S‘sprouqmeljy pou“Asyznqlaried, pUOY[P9Aoy“NIqvjTe}sr,]MQJn ‘gIqQvure}go “pes OOF NOY NgS:5 in the luff is gradually stretched out. This slack in the lacing cord can now be just taken up, and the process repeated, until early care of the sails materially effects their efficiency throughout their life. I profoundly sympathise with professional sailmakers whose work is so often wrongly blamed for the failure of sails, which have been ruined by bad treatment in the “running-in” period. Correct “running-in” is just as essential with the prime mover of a yacht as with that of a motor-car, which brings us back to the analogy eventually the sail is just touching the mast all the way up. The sail should not be hooked to the jackstay at this stage, for it will be found that on the next time out, the sail will have shrunk back somewhat and further stretching is required. After a few outings, the sail can be finally hooked to the jackstay, and the initial stretching process is complete. with which we opened our article, and to a fitting point at which to close it. At a later sails, from the occur when the sail is first used, as the slack date I hope to say more about of tuning-up respect in rly particula angle, user to’ applied be lacing technique cannot easily The jib will be found to settle down more quickly than the mainsail; slight creases may jibs, but these quickly disappear as the hollow and racing. ao —— ne (Continued from page 376) ROYAL FALCON a Most of the hull is black with white paddle individually with a shaped dowel, and of scrap each ply; of piece a in hole boxes and topsides as on the colour sketch suitable and on the plan. When painting is completed the acetate is heated, placed over the hole g resultin The dowel. the with through details may be cemented in place, and the forced balsa to cemented and trimmed are s moulding davits. paperclip on hung be may etc., boats, The rail is built up from headless lill pins and stems, painted, and cemented in place on the 5 amp. fuse wire cemented or soldered in place; decks. The motor power on the original model was the galley chimney is a small cylinder of dowel a Mighty Midget, which already includes a slipped on a smaller diameter dowel. There are several ways of making the cowl 6—1 reduction gear installed. This gear when vents, the simplest being to carve them from connected to the paddle pulley gives a paddle balsa, but a more effective but simple means speed of approximately 100-120r.p.m. with is to mould the cowls themselves from acetate tremendous power. A simple switch is fitted This could be done by spacing to the circuit and protrudes through one of the sheeting. side ports for easy access. At the above various size ball bearings on a metal tray, speed the paddles drive the model rotational laying a sheet of acetate on top, and popping along at a cracking scale speed and all that the tray in the oven for a minute or two. is needed for complete authenticity is the odour On taking out, a soft sorbo pad pressed on to of winkles and vinegar and the strains of the acetate will force the sheet down over “Knees up, Mother Brown” floating back the balls to give excellent representations of the cowls. across the water! An alternative is to make each one Qo ree ek exe att — PROGRESSIVE RUDDER UNIT The baseboard is 3/16 in. ply and the mount is bolted in the approximate position, and the position of the runner is marked on it. The mount is then removed and the slot is cut in the base for the clearance of the 6 B.A. wiper screw. The base is then reversed and a strip of shim brass (.002) is pinned either side of the slot according to rudder movement required The pins used are 4in. brass panel pins, tapped through the brass and mount, and cut off flush with the base. The heads must also A piece of cellotape should be be flush. placed over the pins which come under the mount, as they may touch it. The stud which moves the rudder is a plunger from a house- (Continued from page 388) hold bulb holder with the flex screw cut off. The threaded rod is 4 B.A. and can be obtained easily from model shops. The type of drive is left to the user, as some people like gears, and others prefer a rubber band drive. A point to watch is that the runner will travel both sides without sticking, and it is an advantage to bend a “V” section on the ends of the wiper arm to give ample contact on the strips of brass. The tension can be adjusted after it is soldered to. the screw. Have the wiper tight to start, and then gently ease the ends up until the runner moves more easily. 401 MODE MAKER : Tucker’s WHEREIN H.B.T. IS Topics GIVEN REIN TO HIS eh FREE EXPRESS VIEWS id LAST month in lieu of my usual “Talk” , I wrote an article on “Planing and Planing Sail Boats.” In the course of this, I referred to the well-k nown S.A.: Displacement Ratio. Unfortunately, the printer omitted the mathematical symbols from this, so I repeat it now in words:— Square Root of Sail Area: Cube Root of Displacement. il was also considerably surprised to see a Note inserted by the Editor to the effect that he disclaimed all responsibility for my aerodynamics! In my article I made no reference whatsoever to the real aerodynamics of aeroplane wing constructions, since this has nothing to do with the design of a yacht’s sail plan or keel appendage. However, to save useless argument, and make the matter clear to all concerned, (not excluding summarise the our worthy Editor!!), let us briefly main points of aerodynamics which influence yacht design. These are:— (a) Sails of high aspect ratio are best to windwar d, (b) (c) and plans of low aspect ratio best off the wind, but by setting a spinnaker a high aspect ratio sailplan can be converted to a low aspect one. Owing to the slot effect between the two sails, a jib-mainsail plan is better than a Una rig. The C.E. of each sail moves forward towards the luff. This applies particularly to wind- ward work, and the amount of “the shift of pressure towards the leading edge” is governed by the wind strength. Although I did not refer to it in my article, there is a similar movement of the Centre of Lateral Pressure which affects the underwater profile. But this is a matter of simple hydrodynamics, and not aerodynamics. In this case the amount of movemen t is governed by the vessel’s speed through the water, and the angle of incidence of the leading edge. “ * So now to a totally different subject, as I feel that the letter from Mr. G. Honnest-Redlich in the June number of MopDEL MAKER calls for a brief answer. I am sorry Mr. Redlich feels so peevish about my references to “knob-twiddling” and “sneaking round buoys.” I must admit that I shared his annoyance when I saw the latter expression in print. When my manuscript was despatched to the Editor, the phrase read “snaking round buoys” but by the time it appeared in print, in some mysterious fashion it had become “sneaking round buoys.” This is not nearly as apt a phrase to describe the serpentine course of the average R.C. model. Anent “knob-twiddling,” Mr. Redlich suggests that I should take some interest in the subject. It happens that some years ago, I attended a demonstration of R.C. sailing at the Round Pond. It was a Sunday morning, and I came up from the Outer Suburbs specially to witness it. From memory, this demonstration was conducted by no less a personage than Mr. Redlich himself. The sailing yacht he was using was an A-class boat, and the R.C. included rudder control and sheet trims. During the demonstration, the wretched boat was never permitted to sail more than 416 about 10 yards in the same direction. as she appeared to be settling to Just as soon her work, and sailing, the knob was twiddled, and away she went in another direction. I suggested to the R.C. Operator that it would be more impressive if he tacked the yacht from the leeward end of the lake to the windward end, making long legs and keeping her in the best of the rather light wind. However, he seemed to prefer his own type of fun and games. I have witnessed other demonstrations of R.C. model yachting, but was equally unimpressed. Early in May, I spent a most enjoyable week-end at Birkenhead with my friend, Mr. B. H. Priest. This is the first time I have had an opportunity to visit the Birkenhead Lake, and make the acqaintance of the members of the Birkenhead M.Y.C. While the lake is rather small for big boats like the A-class, it is excellent for smaller classes like the M’s. The Club have a good boathouse, and one of the best fleets in the country, consisting almost entirely of post-war boats, while the general standard of building, fitting and equipment, is very high. Before picking out any special yachts for notice, I would like to mention a new gadget made by one of the members. Whether this will ultimately receive the blessing of the M.Y.A. remains to be seen, but it is an absolutely sure-fire tacking device. Amateusg photographers will recall the clockwork gadget used to secure a delayed action, so that the photographer can point his camera at the group, press the button, and has then time to regain his place in the centre of the picture with an arm round the plump lady, before the exposure is made. A year or so back, it was suggested that a device might be worked up on similar lines so that a yacht could be put off to sail 10 seconds or so on the off-shore tack, before the clockwork pulled the trigger, operated the helm and put the boat about onto the on-shore tack. The M.Y.A. let it be known that clockwork devices could not be tolerated, and that any selftacking device must be operated by the wind, though apparently there is nothing against springs or tension elastics. such as are used for centring lines, beating guys, Liverpool Boys, etc. The new device consists of a small windmill with sails of 3 or 4in. diameter. As this revolves a nut travels along a bar with a very fine thread. When the decided number of revolutions has been made, a keyway comes opposite a feather on a shaft, there is a light spring which pushes the trigger over, and this pulls on a yoke line which operates the steering quadrant. Round comes the boat onto the on-shore tack, and the device then remains idle until the boat reaches her skipper, when he resets the gadget and off she goes again! The windmill, by the way, is mounted on a light pulpit placed on the foredeck just ahead of the jibstay. I should add that the example I saw was the first one made, and the maker expects to make later editions, smaller, lighter, neater and simpler. The Sunday of my visit was devoted to an Open A-class Race for the Birkenhead Parks Committee’s trophy. It attracted fourteen entries, of whom about half came from quite distant Northern and Midland Clubs, including Fleetwood, Newcastle – on – Tyne, Bradford, Birmingham, etc., and quite half of the fleet were new boats this season. Some of these had by no means got over their teething troubles, and it may be too early to comment on these. There were, however, a couple of the large heavyweight monsters that have lately become fashionable, in Juliana Ue (sister of Arthur Levison’s Jill designed by Daniels), and Oberon (sister of Arabesque designed by Littlejohn). The wind was by no means strong and neither of these boats showed to advantage. Last year I considered Roberta the best boat Priest had ever designed, but in his new boat Commando, he has produced a really lovely craft, and I extend my congratulations to him. He has possibly not yet got her quite to the top of her form, but she was good enough to make a remarkable showing and win the race, with 53 points to Roberta’s 49. Many years ago, the late J. G. Feltwell designed Frolic, one of the best and prettiest of the early A-class. Her descendant was Sharma but several other people also claimed to have contributed to the design, and after so long it is not possible to get to the rights of the matter. At any rate. Sharma is a very pretty boat, and remarkably good in light weather. Her lines were modified and enlarged to produce Shalimar, which went to the U.S.A. as our Challenger for the “Yachting Monthly” Cup in 1951, with her owner, Walter Jones, and Ronnie Jurd in charge, but failed to bring home the Trophy. Once again has a further development been made from this design, and to the Sharma, Shalimar line is added ,Shikari. She is a rather larger boat than her predecessors, and their lack of balance would appear to have been overcome. In fact, here is one of the best looking and most dangerous of the year’s debutantes. In the hands of Walter Jones, she is likely to be one of the top boats at Fleetwood. So far among the Southern contingent, I have not seen any new boats in the same class as Commando, and Shikari, but of course there are still a number of new ones to be launched, and many that are as yet not tuned up. MODELLING ALONG KEN PROCTER has provided results of the Sunderland Open Meeting on Whit Monday. Speeds in the 14 Class were lower than formerly as the M.C.A. Class 24 stranded cable was used, as agreed at the 1955 A.G.M. Nevertheless, Ken Procter took Grade A at 68.28 m.p.h., with D. Eaves of Blackpool Grade B at 64.01 m.p.h. Class 24 was a Blackpool walkover, with A. Ellwood (A) at 83.25, R. J. Eaves (B) 74.50 and D. Eaves (C) at 63.06. J.C. Cooke took both Grade A and B in Class 5 with runs of 97.82 and 89.46 m.p.h., while J. Bibby had Grade C at 78.05. In Class 10 neither Grades A or D found competitors, W. Hamilton of Guiseley, taking B at 111.52 and H. Cook, Blackpool, C at 104.16 m.p.h. Washed out .by weather on May Ist, M.M.S.C.’s Open Day at Evershed’s Sports club took place on May 14th with a somewhat reduced entry. Formula 3 attracted twelve runners, resulting in a win by F. Thomas’s Cooper 500 from Alban Adams’s Cooper Bristol; Formula 2 found A. Dowell’s Jag beating his own Alfa; and Formula 1 resulted in a win for Alban Adams’s larger Cooper Bristol from A. K. Pardy’s Connaught. John Benson of the M.P.B.A. tells us that the International Hispano Race is planned for 30th July at Verulamium, St. Albans. Entries have been promised from Bordeaux. and Gems Suzor will also be along. Programme starts at 2.0 p.m. and includes the Hispano—Suiza Trophy for 10 c.c. boats (C & C restricted) and straight running events organised by the St. Albans S.M.E. The R/C event planned by the St. Albans Club has therefore been postponed. On 10th July, however, there will be an R.C. Regatta at Victoria Park, London, commencing at 11 a.m., which will include an open “Set SSS … . Course” event for escapement only boats, and a Main Event also of set cgurse type. Time permitting, there will also be a Novelty Event. South West District held their M Class Championship early in May, when C. E. Harris (Devoran Club) won with his own design Cehart, five points ahead of Bristol J, S. Thomas’s Aphrodite, a boat built to Littlejohn’s original Kittiwake lines. In fine planing winds poor Thomas could not find his parachute, in spite of his comments in April MoDEL MAKER —however, it turned up in the end and he enjoyed some spectacular—and rare — planing! Clubs anxious to start up in the rail racing game, but deterred by those twin evils, lack of finance and lack of “know-how” will be interested to learn that Model Road Racing Cars Ltd., of Boscombe are now making rail tracks complete in sections—four track type— all ready to be assembled and race on right away. Hire purchase facilities are available and an initial deposit of £20 will obtain the goods. Secretaries interested should write to Alban Adams at Ashley Road, Boscombe. Our old friend M. P. Polson, Chairman of the Bombay S.M.E., announces a most ambitious Exhibition, which is being staged at the Jehangir Art Gallery from 22nd November to 11th December. The organisers are anxious to have an international section, and would be glad to hear from any model societies able to send a group exhibit. Already support is expected from the U.S.A., Australia, and several European countries. Address to contact for full particulars is M. P. Polson, 23 Colaba and Chambers, for speedy recommended. Colaba, attention Bombay, Air India, “Mail is