The Model Engineer and Amateur Electrician: 1912

August 22, rgf2. The Model Engineer and Electrician, Model Sailing Yachts. Building, Rigging and Sail so that sails can be carried of any convenient size for light breezes and also that she can carry a really powerful spinnaker. Making. CCORDING to the rules in vogue for model yacht racing no attempt is made to handicap them by any enforced standard of scantling. This being the case, a model yacht (call it a racing machine, if you prefer the term) should be built, masted and rigged as lightly as possible, compatible with the necessary strength, to obtain a craft of . the utmost speed. The advantage will, admittedly, be with the model over the prototype, as the material used, instead of being weaker, as it should be (to be truly to scale), will be found in reality slightly stronger, as it is possible to find straighter grained timber free from knots and flaws in small pieces than in large pieces. As, however, models have to be sailed on water of the same density and stand up against the same breezes that a full-sized ship has to withstand, it is quite impossible to reduce all the conditions to scale. It is therefore advisable to take full advantage of all the items in favour of the model. In the year 1888 or ’89, when I was a member of the Serpentine Model Yacht Club, the advantages of lightness in building and rigging were fully appreciated. but, judging from recent articles and designs which have appeared in THE MopeEL ENGINEER and other journals devoted to this subject, little progress has been made in this direction, and boats are built heavier and rigged more clumsily now than at that date. As it is easier to write on a concrete example than in generalities I have taken a rather exaggerated design for a 10-metre (International Rule) as my example. See two-page plate for Sheer. Half-breadth, Construction Plans, and Diagonal lines. See page 182 for Body Plan. {79 The dimensions, where given, all refer to a 10-metre boat, but scales are given both for that and 12-metre boats. I have chosen this type as it offers some complications that do not arise in a fin keel boat or a boat with little or no overhang, but my remarks will cover those types equally well, and with the instructions here given I believe anyone with fairly capable hands and an average amount of common-sense could build any type of boat from a feather-weight racing cutter to a high powered motor boat. I should here mention that I have not gone over the ground already covered by ‘‘ Model Sailing Yachts ’’ (Marshall’s Practical Manuals), except where my system differs or where the directions given do not apply to the type of model here described ; so anyone wishing to build from my description, who has no previous knowledge of building, should obtain a copy and read it in conjunction with this article. I do not claim that the lines are by any means perfect, as they are my first attempt at designing under the International Rule. The object that I had in view when I started to design was to get out a boat which would be a good all-round sailer, capable of being raced either as a t1o-rater under the S.A. rule, or as a 10-metre under the International Rule. I find, however, since getting out the designs, that ro-metre boats are not in favour with London Clubs, so perhaps I shall build her as a 12-metre. I have designed the sail plan of ample proportion Building. Materials: For the stem, keel and general frame- work, birch is as good as any timber. The knees and fittings are best made from holly or some fruit tree, such as apple or pear, the knees being naturally grown. For the ribs either Canadian cheese tubs, which can be bought at any grocer’s for a few pence, or hazel rods split down and planed to thickness, are as good as anything. For the sheeting cedar, straight-grained spruce, American mahogany, English maple, or, in fact, any wood which is not given to too much shrinkage and is light, straight-grained and easily worked may be chosen, but, in any case, should be sawn as nearly on a radial line to the growth of the tree as possible, as there is much less shrinkage in this direction than along the growth rings. The timber is best bought in a block about 4 ins. thick and 6 ft. long, and should be sawn up at a saw mill with a fine saw into boards a little over 3-32nds ins. thick, which, if well done, will accurate that little planing will be required. be so Later I shall describe two systems of building, both of which have their advocates—one of them requiring about 10 boards and the other 20; but in either case it is as well to have a few spare boards whilst you are buying. The deck should be of clear yellow pine or poplar, and is better if made in cannot be obtained one piece; but if a board sufficiently wide, it should be made in three pieces so that there is no join down the middle. For deck beams, stringers, etc., clear straight-grained spruce can be used and this can often be obtained from Danish egg boxes, the bad boards of which can be used for cutting out the building moulds. The remaining materials required are about 4 ozs. of litharge, 4 ozs. of oxide of zinc (both in fine powder and intimately mixed), 4-pint of best carriage copal varnish, }-pint of best gold size, 2 ozs. of brass gimp pins ( in. long), one ball of very even twine (about 20 S.W.G.) ; one packet of 3 in. brass screws No. 00, three dozen brass screws (assorted, # in. to rfins.), 15 lbs. of scrap lead, three-pennyworth plaster-of-Paris, 5 ft. each of } in. and 1-16th-in. brass wire, a few inches of strip brass } in.by 1-16thin., a few square inches of No. 30 gauge sheet brass or German silver, a little silver solder, a little soft solder, borax and flux, } lb. glue, } quire No. 14 glass paper and 6 sheets each of No. 1 and No. 0, $ pint of French polish and a cake of Monkey soap. This completes the materials required for the hull, and with careful selection the whole can be bought for 8s. 4d. including sawing (this from actual purchase). It is advisable to buy the sheathing at the outset and have it cut and stacked flat with thin battens between to allow them to season in a warm place for a few weeks. The sheathing being so thin will season in a very short time, if packed so that the air can circulate freely round it. Next, two pieces of 1} in. by 14 in. quartering 5 it. long, and 17 pieces of ? in. by }in. strip deal 15 ins. long, and three dozen 1} in. screws, will be required to make a “ladder” on which to build the boat. This old-fashioned system for some rea- son seems to have been entirely forgotten, but as The Model Engineer and Electrician. August 22, 1912. L.W.L., 31°83; L.0.4.5 53°35 :: Beam, 8:5; Dé 6 7 SHEER PLAN. L 0. i = Z 2 : fe + 2 T| ee ia ~ese5., 10 aS B pa $ f f 2 cale tor 12 metre mode! g 1 4 Pi) 6 :. Hl ‘ y D W2Ins it L ( a E -* ~ Scale for 10 metre model = N x ——— \ eel ee a el “ | DIAGONAL LINES. HALF-BREADTH PLAN. Cover Board eeee (0 m 12 | Deck Bea Stringer /o be £m Maples Hatch T 38 lo Bulkhead 0 Morhice orhce= Dowels’ B” = . << == oe Se Naferal afera WA AW \ \ Petal \Dowel| \\ \\\ ! J Rie Rib ai = Width Reelaft papnest Wa) Washer Ns \\ Lead and Dead Waod \ \ Brass sirdp 6 CNW : Keel | " August 22, tgi2. The Model Engineer and Electrician. 181 5 /bs.; Overhang, 10:2 forward, 11°3 aft. VE Deboes- Brrnyhler SS DESIGN FOR A 10-METRE MODEL YACHT. By V. W. DELVES-BROUGHTON. Stringer Beam / Knee Bowsprit Bits Shaw lionip Z Brass plate cipetted Toke! KE Sechon thro Rib soldere A Bowing ad of Head of screw Jo be tiled away Method Phang SS ee * and slem Stringer soldered fo lead ess wire soldered on ~tinal adjustment of Sein 2 Sechon ot Bowsprit Bils CONSTR caei. NS AND . x ;, BS und Plan of Fore Peah Filing Pece and Deck Beam rvet Showing manner ~ 2a 1 (Not fo Seu/e) i 182 The Model Engineer and Electric ian. it offers many advantages over the “ Buildin g Board” system I personally advocate it. This will cost another 2s., say. Beyond this nothing is required for the hull beyond a few tools. 1. A smoothing plane (an iron plane by preference). 2. A small thumb plane hammer. 3. A light 4. A ro-in. bastard flat file. A pair of pinchers. 5. 18. August 22, 1912. A medium sized screwdriver. 19. A good varnish brush (one that has been well used by preference). And last, but not least, a good oil stone: 20. A pair of good strong scissor s will also be re- quired for cutting brass, etc., but probably these can be borrowed from a trustin g wife, sister or mother. (9d.) A bench of some sort is an absolute necessity, and if the kitchen table is used for this purpose a perfectly true planing board, at least 1 in. thick and ft FT ft 7 i i or = cs oo OQ PALE x a i i1) oo oe ea | f a\_ / 5 VA = —Y~ . = earn Z ~ | any fre 7 | /—HLX f sa LWL. Bopy ODY PPLAN FOR ae a Se sal alls = AwAin LZ ATOR | 10-METRE a MODEL Yacur. | Fal A —j—-+-+ V. W. DeEtves- | ee ie F a a i (2) (a) orto / ! i 2 2 t iT 3 3. H 7 4 I 5 6 i, 8 ez 9g 4 Py a .» A pair of round-nosed pliers. - A small saw with brass back. . A -in. chisel. . A f-in. chisel. . A pair of dividers. A try square. OW @ /0 /] 12 Ins Scale for 12 melre mode/ 6 t 7 t 8 t Scale for /0 metre model . OK BrouGuTon. Es I | 8 Del 1 iewe . A rule, - Two or three assorted bradawls. . An old dinner knife. - Two or three small files (assorted shapes). . A drill of some sort. - A cabinet-maker’s scraper or a bit of anold saw blade. 9 t 10 f / t 12 Ins =| 5 ft. long, should be obtained, as it is next to impossible to plane up the sheathing with sufficient accuracy on a bench which is either springy or out of truth. A vice will be found a great convenie nce, but a fair substitute can be contrived with a pair of hand screws screwed to the bench. About half-a-dozen very fine awls will be required for pinning the planks on during the process of fitting and these can be convenie ntly made of broken hat pins driven into hard wood handles (if they pull out, a little salammoniac will rust them in securely). @agust 22, Igt 2. * The Model Eng ineer and Ele ctrician, 183 gauge for pla nin g up the pla nks and dec Mekeess will k to be shown in next issue, The last few Mes of the adjust ing screw sho uld be file Se =; nicely d off and rounded, the fixed point is made with > headed scr ew with the not ch file d out after se : far as cannot brass gimp pins, in boring blocks one side the second side from the first before it is finally fixed to the rabbet in the frame. The fine $-in. screws should be temporary Tibs at 9, 4, 3, and A are half ribs running from deck to keel on each side. The ribs, as already cutting a brown paper pattern of each plank, fitting fit in. Having fitted all the planks the ribs may be bentin; those at sections 1, 6, and 8 being single ribs edgeways fitting of the plank, and for the same reason the planks must be fitted alternately on each to be both Wherever the planks come in contact with any per- manent fixture, such as the frame or bulkhead, they should be painted with a mixture of equal parts by weight of finely ground litharge and zinc white, mixed as required to a fairly thick cream with a mixture of L equal parts of gold-size and copal varnish. This is best mixed fresh. In all cases the planks should not be feathere d off to a sharp point, but should be cut off with a square end, as shown in Fig. notch in extreme the end they should be boiled for five or six hours to get all the sap out of them. They are then bent into the hull, the ladder being turned over and supported by two ends, and clamped to the top strake with upholsterer’s clamps and left to dry. If there is any difficulty in bending the ribs round the corners at the keel, etc., they can be heated over the flare as already described for bending the planks. The half ribs must be treated in the same way, 9, making a corresponding succeeding fits. Fics. 8 AND 9. An plank, into which the alternative method is to cut the rabbet in steps, but this necessit ates leaving the rabbet to be finally finished till the planking is undertaken (see Fig 10). The bottom edge of the plank (7.e., the top edge as the boat lies on the ladder) having been fitted, the top edge is marked off with dividers at each mould and a line drawn through the points so obtained, and the top cut out to shape. The absolute fitting of the planks is done with the Fic. table knife, which is run round the pencil marks, and the final fitting is done with the thumb plane, scraper, and a stick with glass paper glued to it, used in the manner ofa file. In the narrow plank system very little fitting is required, and practically all that has to be done is to bevel the edges of the planks where they round the bilge, so that they do not gape. Whilst fitting the planks, if an assistant is not available, the small awls made out of broken hat pins will be found invaluable for temporarily holding them in position. The holes in the moulds made during this process must be plugged and the same hole in the plank used to tack it down, except that the lower ends must be slipped into the mortises previously cut in the keel. When thoroughly dry, after two or three days in a warm room, they must be taken out one at a time, and To, if they do not accurately fit in the positions they are intended to go into, they must be heated over the flare and set on the side next to the Having been finally fitted they should be with the mixture of zinc white and litharge, described, and replaced in position, and screwed to the keel and clenched to the planks. painted already finally planks with the brass gimp pins which have previously been softened by being heated to a dull red heat and plunged into water. The nailing should start at the garboard strake and be continued up to the top side. Next, the space between the ribs should be filled in with filling pieces the same width as the The Modei Engineet and Electrician. August 29, 1912. deck stringer or inwale, except between sections 4 and 6, which should have a strip of wood 2 ins. wide by } in. thick at top, tapering to 1-32nd in. at the bottom, glued in position, as shown in the Construction Plan, with insoluble glue, and held in position with clamps till dry. This piece of wood should have its grain running diagonally across it. Moulds Nos. 5 and 6 will have to be removed to get this strip of wood in, and No. 5 can be discarded permanently. No. 6 will have to be put back, however, after having pared away the sides to make room for the extra thickness of the filling piece to ensure the beam remaining unaltered. The next items to be fixed in position are the rigging loops and eyebolts. These are best made of 16 S.W.G. brass wire which should be bent round and recessed into the filling pieces, as shown in Fig. 11, being held in position by the strip of hard wood B, the holes being bored through from the regular curve, without any break. made a well-fitting cradle for her to lie in, proceed to remove the moulds, starting at the middle of the ship and working fore and aft alternately periodically looking down the rungs remaining in position to see that she does not twist. Mould No. 5 has already been removed, so it is best to start there. Proceed to sew the planks together with the twine, which should be cut into convenient lengths (about two feet) one end being hardened by having been dipped in weak glue, in lieu of a needle, and the other end provided with a knot. (To be continued.) sure getting the loops to stand the right height In a similar manner eyebolts must be fixed where required for mainboom guy, spinnaker sheets, It is as well to put in running backstay, etc. plenty of these, as they weigh very little and are difficult to fit satisfactorily after the deck is on. In the same figure an alternative design is given for these ‘items, made out of sheet brass, but they are more difficult to make, weigh heavier, and are not so strong. Those not in use can be left bedded in the gunwale till required, as they can easily be The tops of the ribs must be cut away flush with the stringer, and the filling pieces also dressed off if they are ‘“proued ‘’ in any places, care being taken not to split off the projecting edges of the top strake. Next take the boat off the building ladder by removing all the screws from the rungs, and, having inside both for the upper and lower screws to enabove deck. 2058 A Successful Steam-=Driven Model Aeroplane, By V. E. Jounson, M.A. N the following article is given an account and I full description of that (at present) rava avis— a steam-driven model aeroplane of small size that has actually flown. The model as originally constructed is shown in Fig. 1. The total weight of the Brass tube . model (without fuel) was 3 lbs. 14 ozs. The centre of gravity was about 2} ins. in front of the main plane. The span 5 ft. 8 ins., the length 4 ft. 6 ins. The landing chassis (which has since been altered, see Fig. 3) was arranged as far as possible so that the chief forces were in tension. The combined front wheels and skids (see Fig. 4) were strong rubber sprung, and so arranged that on alighting the wheels could twist laterally about their axis. Fic. It. exposed by cutting away the gunwale when neces- sary. Plates to carry the horses must also be fitted, as shown in Fig. 12. After having made quite sure that a full provision of ring bolts has been made, the stringers may be fitted along in the recesses provided for them in the moulds, it is as well to put these in with insoluble glue, clamping them in position and screw- ing them from the outside, using a screw at every two inches and making sure that a screw passes through each of the ribs. As already stated the best material of which to make the stringers is straightgrained spruce. The section for the stringers between moulds 3 and 8 is $in. by 3-16ths in. diminishing to % in. by 4% in. at the stem and transome. It is as well to leave the top strake standing up all round a shade high and the stringer should be fitted exactly the thickness of the deck below the deck line, making sure that it follows a This was rendered possible by firmly fixing the axis to a double strip of tin (thin sheet iron), which was curved so as to fit loosely over the top of the rear part of the skid. A loose-fitting pin held it in front, and in the rear it was rubber bound. The single rear wheel and skid (Fig 1), now the front (Fig. 3), is shown more in detail in Figs. 5 and 6. After having left the ground the strong rubber band pulls the skid well up, and the wheel in consequence being depressed, on striking the ground on landing, the rubber is stretched until the skid’ strikes and slides along the ground, as shown in Fig. 6; the pull of the rubber acting as an excellent shock absorber, and the model quickly recovering its normal position. In Fig. 7 is shown the front skid (of steamed and bent bamboo) and the elevator (uncovered). This was at first so arranged as to swivel round on striking any obstacle without losing the angle at which it was set ; it is so depicted in the figure. It was found, however, that an elevator of this size was not held sufficiently rigid in this manner, and it was afterwards secured more firmly, as shown in Fig. 8. The method shown in Fig. 7 is, however, a very advantageous one where The Model Engineer and Electrician. September 5, 1912. Model Sailing Yachts. By V. W. DeELves-BRouUGHTON. (Continued fiom page 205.) a piece of hard IRST thread the twine through F linoleum and then proceed to sew the planksof together, as shown in Fig. 13. placing a slip linoleum under each loop on the outside, to prevent it cutting into the wood. The thread should be well painted with the mixture of litharge, zinc- white and copal varnish as the sewing progresses, and when thoroughly dry a sharp chisel is used to cut away the loops and linoleum on the outside, leaving a series of staples formed of string securely embedded in the wood. When a suf- 225 in so as to thoroughly penetrate the muslin, using a short-haired stiff brush for the purpose—an old tooth-brush answers admirably. Having made sure that all the internal fittings are in place, thoroughly paint the inside with the usual mixture and fit the deck, cut out the hatch- way, fix the coamings and the bearing beams for the mast, and then proceed to fix the lead keel in position. I have not entered into the question of fitting the deck, as there is, as far as I know, no royal road to success. It is a most fiendish bit of fitting and requires patience and care, but beyond this no ficient number of the moulds have been removed the deck beams and hatch framing shown in Fig. 15 should be fitted; a template, Fig. 14, being made from which the curve of the deck beams is set out, the same template being used for all the beams. The hatch frame should be mortised in between – two deck beams and strengthened with brass angle brackets clenched to the wood and provided with beadings on the lower side so that the boat can be lifted by either edge or by the deck beams them- selves without fear of breakage or damage to the hands. In a similar manner the mast support shown in Fig. 16 and in the Construction Plan is fitted. This is a great improvement on the system of having the mast step at the keel, as there is no possibility of leakage and the complication of slides, etc., is done away with, besides offering a lighter construction. This system was first used by Mr. Teague special ‘‘ dodge” is available. A good deal of trouble may be saved by first cutting out a template in thin cardboard, but this is almost too obvious to , require mention. The Lead Keel. To cast the lead, remove the pattern piece from the bottom of the boat and paper all over it till it is about than the final keel is to be. glasspaper off any inequalities proceed to paste 1-16th in. thicker Then, when dry, and smear with Next make a rough melted tallow or mutton fat. wooden box into which it will fit, leaving at least 4 in. clear all round, and in the bottom tack two narrow strips of wood so that the top of the pattern comes just below the top of the box. Then having poured sufficient water into a bowl proceed to stir in enough plaster-of-Paris to make a very thick cream. Finally, whilst holding the pattern down, pour the plaster into the box till it rises just above the pattern; retain it in this position for a few minutes till the plaster is set and in about half an hour scrape away the rough top and remove the pattern. The mould must next be thoroughly dried, first by a gentle heat and finally in the oven. When thoroughly dry melt the lead in an old saucepan or a lead ladle, if one is available, and having set the mould perfectly level and skimmed the Delzi/ of Se wing Fic. 13) and myself when we were Schoolboys at Melbourne, but who originated it is lost.in oblivion. The deck should have been planed up some time before and painted with copal_ gold-size, litharge, etc., and allowed to dry, any joints having been previously glued together with glue and chrome alum and finally laid on the floor, bottom side up, and a bit of butter muslin stretched over It} tacks being driven into the floor all round, about an inch beyond the board, after which a coat of copal varnish and gold ‘size should be well rubbed dross off the lead pour into the mould till it is brimming full. When cool, before removing from the mould plane off the tops with a carpenter’s plane, which must be well greased and set fine. No harm will be done to the plane. Next fit to the heel piece of the stern post. This is done after the keel has been removed from the mould, first by cutting away any irregularities with a chisel and finally The keel must then be bound temby filing. porarily to the hull with broad tape or webbing and two holes bored for screws as shown in the Con- struction Plan (pages 180 and 181). This is best done with a twist drill with a lengthened stock, which can be made by twisting a bit of sheet tin round to form a tube and soldering the tube itself and the drill into the tube. Any convenient means of driving the drill may be used, but a handle like a gimlet will answer the purpose admirably. Patience and plenty of lubrication must be used or the drill will seize—on no account apply too much The Model Engineer and pressure. Ordinary brass wood screws can be used for fixing, and chosen of such size that the core of the screw is a shade smaller than the hole in the lead. The two screws from the inside of the boat for attaching the keel are so arranged that they can be removed and replaced without removing September 5, 112. Electrician. (after painting the joint over with copal varnish and litharge, and screwing on permanently) proceed to trim up to shape and smooth off, using first a carpenter’s rasp, or, better still, a Dreadnought file, and finish with a scraper and emery cloth. the It is advisable to paint the hull with a mixture BrassL plales No Fic. 15. Deck beam Defz// of Halch deck, should it be found necessary to alter the lead at any future date. If any difficulty is found in to cut its own thread obtain getting the screw an iron ‘screw of the same size and file four flats on the end and use this as a tap. lic. Really there is no difficulty in boring of whitening mixed with common paste (which can be easily removed with a sponge and hot water) to keep the wood clean whilst finishing the lead. A mixture of lead and antimony, six parts of the former to one part of the latter, is much superior to plain lead as it is much harder, which enables 16. [ ESS WS) | j Morhice tor upright Delzils of Support for Mast Step a hole in lead, but it substitute for a twist takes time. drill can be A very good made out of a bit of steel wire—a wire nail will do on a pinch— by hammering it flat, filing it up fairly thin and parallel, heating it red hot and twisting it up with two pairs of pliers and finally sharpening the end; for boring lead, it need not even be hardened, Next Foot plece 2 5 we * a better finish to be put on, and subsequently is less liable to damage in sailing. The outside should next be finished off and for this purpose a cabinet-maker’s scraper will be found very convenient but must be thoroughly sharp. If my readers do not know how to sharpen a scraper they had better get someone who does to show them how, till the whole surface is thoroughly “ filled.’’ After as there is a certain knack in using the burnisher which is somewhat tricky to attain. Even experienced cabinet-makers have not all the same paper proficiency a in this line: one known to the writer, although a first-class man, could not sharpen a scraper after 30 years at the trade. Then, whether the boat is to be varnished or finished in oil colours (after having finally smoothed the whole off with glasspaper, starting with No. 14 and working through each grade down to No. 0), proceed to fill in with “hard filling,’’ which is made of tallow mixed whilst warm with plasterof-Paris to the consistency of putty and coloured by the addition of any suitable colouring matter. As much as possible of this filling should be removed with a strip of wood used as a scraper and the last traces removed from the surface with a rag. The next process is to French polish the outside (To be n nN The Model Engineer and Electrician. ~r September 5, 1912. standing for a night rub down with very fine glassor pumice second coat power of and French olive oil and polish. Again give allow to stand for some hours, in a warm place if possible, and give two or three coats of copal varnish, allow- ing plenty of time to dry between the coats, and rubbing down each coat with pumice powder, soap and water, using a cork rubber covered with felt or flannel and giving a final polish with the bare hand to which a very little whitening should be applied from time to time. Even if the boat is to be painted it is advisable to thoroughly ing as this French polish the hull before paint- gives a very even surface which will not “rise ’’ when paint or varnish is applied ; consequently much fewer coats are necessary and the weight of the hull is kept down. continued.) Some Further Points abou t Model Hydro-Aeroplanes. By V. E. N Tue MoveEL ENGINEER of May 23rd issue | i dealt with certain points in the construction of these models, and towards the end of that article reference was made to the possibility of combining the float, hydroplane, and aerofoil surfaces all in one. Since that date I have carried out a fairly large number of experiments with — floats of various kinds, and as these experiments or, to speak more correctly, some of these experiof amount ments—have met with a considerable Fic 9. -VIEW OF A success, they will not be, I think, without value to those about to take up this new and fascinating branch of model work, combining as it does both marine and aerial engineering. It is of considerable importance to duly note at the outset that the principle of support in both the case of the aeroplane and the hydroplane are the same, viz., the deflecting or sweeping downwards of a layer or stratum of air or water in order that they may derive their support from the upward reaction to this downward force which is employed to bring about an acceleration of some given mass Jounson, M.A. of air or water. Bearing this fact in mind, and that there is the case of the true hydro-aeroplane as opposed to the aeroplane supported on more or less punt-like floats, most of my experiments have been made with a view to determining how far the question of (initial) flotation, and also the principle of the hydroplane and aeroplane, can be combined in the same member. The question of ample flotation, wideness of supporting base, position of C. of G., etce., have MopreL HypDRo-AEROPLANE. already been dealt with in my former It is necessary, however, to add some remarks with regard to the article. further POSITION OF THE CENTRE OF GRAVITY, or, to speak more correctly, the position of the centre of main flotation with reference to the centre of gravity. I stated in my former article that the machine must be well “ floated ’’ ahead of the centre of gravity. The remark still holds good, but it requires amplifying somewhat; it depends very much on the nature of the floats employed, September 12, 1912. The Model Engineer and Electrician. the carburettor had to be below the level of the tank to obtain feed on the jet. The special wire strainers, made by my brother, are § in. long by 1-16th in. They are single-acting— that is, no left-handed screw thread is used. These strainers work very well and do not slack off. The wire landing wheels, the construction of which may be of interest, were made as follows: ins. A piece of }-in. by 1-32nd-in. strip steel, roholes long, formed the rim and was drilled with 24plates, to take the piano-wire spokes. The hub two for each wheel, and 3 in. diameter, were cut from 1-32nd-in, steel plate and drilled with 12 holes each for the spokes. These hub plates were fitted about over a } in. internal diameter brass tube which % in. long which formed the bearing, and was provided with a tubular distance piece between plates. The inner ends of the piano-wire they fitted into the hub plates on alternate sides, in a cycle wheel, the spokes being crossed and fitted tangentially as usual. The outer ends of the spokes sever- the hub spokes were bent sharply to a right angle, where as projecting through the holes in the rim were ally tightened up by curling over the ends against the rim, accuracy being ensured by using a gauge and mandrel. The ends of the spokes at hubg plates and rim were also secured by well sweatin with solder. The wooden tyre was composed of four thin lamine of American elm, about } in. thick by } in. lamine wide, steamed to shape and the several position integrally secured by glue and clamped in shape to dry. The tyre was afterwards finished towas the and a remarkably light and strong wheel result. Model Sailing Yachts. By V. W. DrELvEs-BROUGHTON. (Continued from page 205.) Sail Making. HE first consideration in this matter is choice of materials, and if expense is no objecta closely Tussore silk cannot be beaten ; but not woven find suffionly is it expensive, but it is difficult to good deal ciently evenly woven. Besides costing a far as is, as itself, it is also expensive because there stuff, I know, no perfect binding material for this of except strips cut from the selvage edges offorsilk each the same quality, and this means that, 2$ yards about suit of sails for a 36 linear rater, that more silk will have to be purchased beyond about required to cut the sails, so that, altogether,always 64 yards, costing 2s. 113d. (these thingsros. 44d. or have an odd 3d. stuck on at the end),ing may go for a suit of sails; even then someth d! wrong in the making and another lot be require ve, the Having dismissed silk as being too expensi 7.¢., next best material goes under several names, c. Jaconet, Victoria lawn, or cotton cambri should ~ In choosing the material particular regard be paid to the following points: it must be light— not more than }+ ounce per square foot; it must be closely woven-—particular care must be taken that the weft runs evenly and straight across the stuff at right angles to the selvage , that it is smooth faces, and free from nap; that it is similar on bothfinally, j.c., that it has no right and wrong side, and, that it is free from dressing. 255 It is better to purchase fairly narrow stuff, as, if a greater width is required, it is easily joined, and to waste. first, and nap does does not Having tested and finally purchased pucker. the material, together with a reel of Clarke’s cotton No. 30—a reel each of black and white linen thread No. 35—a packet of needles (not too small), and a hank of %-in. cotton tape, the first thing to be done is to draw two threads at each end of the piece of material and, using the marks as a guide, proceed to hem each end. The cotton must be rewound on a notched stick and the tape undone, and these three items—t.e., material, cotton, and tape—must be boiled for at least an hour in plenty of water, being constantly turned over during the process. If available the material should be put through a wringing machine, otherwise it should be hung out to dry as it is. Onno account should it be twisted up as in the ordinary process of wringing by hand, or the direction of the threads in cutting jibs and try-sails it will cut less It is advisable to purchase a small piece take it home and boil it to see that the not rise, and that it shrinks evenly and forming the weave will be distorted. Ifa large table (which will not be damaged by having tacks driven into it) is available one of the hems can be tacked along the end, starting at one corner and then pulling the other end of the hem out with a pull of about 4 Ibs. (a spring balance is advisable for the purpose), subsequently putting in tacks all along the edge (If no table is at intervals of about 2 inches. available the floor must be used, but this is a Next proceed with one of the back-aching job.) selvages and stretch this out with a pull of about 12 lbs., taking care to pull it out exactly square with the hem and tack that all along in the same manner. Finally, tack the remaining two sides in such a manner that the threads in the material are straight and square with one another. Next proceed to set out the sails, using the first stretched selvage as a base line as shown in Fig. 1, marking the cut edges about } in. larger than the sails and running another pencil line % in. inside wherever the tape is to be sewn. Next proceed to stretch the tape, tacking one end to the table and pulling the other end out with a spring balance with a pull of about 4 Ibs. Whilst still in position, before cutting out, proceed to tack the tape on (using the black thread), passing the thread twice through both sail and tape at each spot and se- curely tie. For this purpose a fairly long needle which has been softened and bent at the tip will be found useful (it need not be rehardened). If the material is not sufficiently wide to cut the sail all in one each piece must be separately taped in the manner above described and the selvages marked off with pencil ticks at regular intervals of about two inches, which, when the point A is laid on the point B and the point C on the point D (see Fig. 1), will coincide with one another after the manner of a proposition in Euclid, thus ensuring the pieces being sewn together with an even -tension. The pieces of tape on one section.of the sail must be left with sufficient length to make a lapped joint when the two portions are put together. When the tape has been tacked to the sails the latter may be cut out and sewn as shown in Fig. 2, after which they are completed as shown in Figs. 3 and 4. Ihave previously specified Clarke’s cotton, as this is the only cotton that I have found 256 The Model Engineer and Electrician. possible to sew with after being boiled. If it is rubbed on a bit of dry soap it will be found less prone to kink and get into September 12, 1912. suit of sails set properly by this means. The corners of the sail can be finished off with lady’s dress eyes neatly sewn on; that at the “ tack” being provided with a small hook to fix to the goose neck tor the main sail. The “ luff’’ of the sail must have special hooks sewn on as shown in Fig. ‘ boggles,’’ which it is very liable to do if used by an untrained hand. In sewing two selvages together the two pieces should be laid back to back and sewn over and over with very fine stitches, not taking more than 5. Sails should not set quite flat when hanging Joose. but should be slightly tight on the leach and about 1-32nd of an inch of the selvage into the stitch. Fairly long stitches can be used in sewing bag slightly at the luff. The Yankee sail-makers Selvage t H H Salvace He Fic. the tape on, but they should be regular, and neither too much of the tape or sail gathered under the needle, and great care must be taken with the “ tension,’ as, if sewn too tight, the cotton will either pucker the sail or break, and if too loose the tape will bag on the sail and look unsightly. This system of cutting the sails whilst under tension, using three times the pull on the warp to that on the weft, obviates cutting the sails on a curve and although they may not set quite flat in a calm will draw infinitely better in a breeze. Ts can beat us all round, and it 1s one of the reasons experienced Yankee in so much re-capturing sails, however, English in a calm. The said that that is difficulty the cannot has been America Cup. compare with are very par- Americans ticular in guarding their secrets, and, as far as I have heard, no one exactly knows how they are cut and made. It is said that in seaming the cloths they are stretched and tacked much as I have described. A great deal depends on the manner in which the sails are bent, and an apparently badly cut sail Cut Edge \ or pin a pleat in before cutting in any way, and then trying the sail in the wind to see how it sets when full. Finally, it can be cut and taped. In no case should a sewing machine be used, as it is next to, if not absolutely, impossible to make a Tape | oid Fic. 2. Fic. 3. 4!I ere: Fic. 4. It a sail sets badly by being stretched or from | Cul Edge, Fold. an original bad cut, it can often be improved by cutting a notch out as shown by dotted lines in Fig. 1; but it is advisable to set the sails, and tack Tape By} Tzpe Sewn Fic. 5. can be made to set well by re-bending and adjustthe peak and throat halyards. A well-known expert has said ‘‘ The hull does ing not matter in the least—the man is more important. and the sails are everything.” This is an exaggeration, but it serves to show the importance of sail- making. A main sail, if properly cut and bent, should set all right, and battens should not be necessary, in The Model Engineer and Electrician. September 12, 1912. A fact they should be avoided as it makes a sail so difficult to store. Sails are a trouble to make, and when made should be taken care of, and this is best done by rolling on a paper tube of fairly large diameter, the sails being pinned in position with safety pins and covered with an American cloth case. A sail should never be folded and never put away wet. Where several suits of sails are carried it is convenient to make several tubes that will go one inside the other with sufficient room for the booms, gaffs and sails between each tube. Spare booms, and gaffs, etc., can be carried inside the smallest tube. Tf it is desired to rig the model as a cutter care should be taken in cutting the top sail that its “centre of effort ’’ comes vertically above the centre of effort of the main and head sails combined, so that whether the top sail is set or not no alteration will be made in the fore and aft trim of the sails. It should be borne in mind that the head sails are very little good in helping a boat forward, and should only be used as steering sails, and as such should be kept reasonably small. A spinnaker is cut entirely differently from any other sail, for whereas all other sails should set as flat as the proverbial board a spinnaker should blow out into a regular balloon. For a model the best form of spin- naker is that which is set from the mast head and _ brought round on the main sail side as far as the from there to the Da with a bowsie and hook are provided to fix to one of the main rigging loops, and at C a strap is sewn on to fit round the reduced end of the spinnaker boom. This method of setting a spinnaker enables it to catch the bulk of the wind slipping past the mainsail and tends to lift the bows of the boat. This article is based on experience dating back some twenty-four years, but judging from what I have seen recently most of the points given have been‘forgotten, or at any rate are neglected by the present generation league, in boating of of ago, from Crookhaven, I gave Fic, 6. THE SPINNAKER model yachtsmen. all sorts, H. My col- Teague, has kept up sailing continually, and could no doubt amplify this contribution by an article on what he has done since I left off. (To be continued.) / at years in the M. E. a photo and description of a model Wheatstone Transmitter (see No. 371 June 4th, 1908). I am now giving some photographs of my model morse inker. This model was commenced and finished about 1tg00—just after completing the transmitter—but turned out useless as an inker owing to errors in design mentioned below. It was therefore only used as a sounder on a short private wire between our office and place of residence. To remedy the faults in design meant a good deal of work and scheming, and the model consequently lay idle for several years after the private wire was demolished. Last year. however, I tackled it when on annual leave and almost completed it, when it again got shelved for lack of a few hours’ time and patience to complete it Now I have succeeded in finishing the model and I hope the photos may prove interesting, if the description is a trifle ‘ dry.” The driving gear for the tape is made from the wheels of an old substantial ‘‘ Wag-at-the-Wa’, ”’ fe tack By W. B. FEercuson. NOME wy ey is cut with five gores which are joined up with tape. At A halyards are attached, at B a hook is provided and attached to bowend, Inker. Y spinnaker boom. The sail, see Fig. 6, short Model Morse 4 main rigging, thence the fore stay and sprit 257 which for I 2s, purchased 6d. These from clocks a telegraph are messenge: chain-driven, an the winding up is done on a separate drum from “driving ’’ drum, so that the movement is 1 stopped or retarded by the action of winding u; This principle was adopted in the design of thx inker. My error in regard to the choice of geari was that I arranged the fan governor on an axle too near the driving wheel, 7.e., on an axle which did not revolve sufficiently fast in proportior 274 The Model Engineer and Electrician. are to be made—hounds, gooseneck, halyards, etc., where the spar should be left solid for } in. or so, ; and if there is any part exceeding 20 diameters in length without any such fixture, a similar solid | portion should be left, and finally all the central keep it clean, and to prevent the wood absorbing too much varnish subsequently. In making spars of bamboo, a very similar procedure is followed, the only difference being that it has to be split from end to end with a thin knife. portion must be scooped out in the intervening portions with a gouge, till the spar is only a little over 1-16th in. thick. September 19, 1912. The best bamboo to be obtained, as far as I can find out, is called ‘‘ best Calcutta white garden A convenient tool for finish- ing this portion is made out of a bit of thin steel, § rounded off at the end to a semicircle, clamped canes,’ and I am told they come from Bangkok ! Great care must be taken in selecting them to obtain them as straight as possible, tapering evenly, b>tween two pieces of hard wood, and used as a router (see Fig. 1). The thickness can be judged by holding the half spar up to a strong light, when without flats on the joints where branches have See Fig. 2. And when purchasing it is advisable to buy a few more than required, —_—_—ibeen cut off. resign DEcK an even glow should be seen all over. PLAN oF FITTINGS AND RIGGING. This is tech- as the process of splitting is by no means so easy Having finished the inside satisfactorily, the whole can be cemented together. For this purpose, “ Seccotine,”’ or a similar cement, is superior to glue, as it takes some time to whip a spar after knife will run to one side or the other. By going slowly to work and manceuvring the knife, it can be brought back to the centre with a little skill. In scooping out the bamboo, the knots or joints nically known as ‘the violin-maker’s gauge.” putting it together, and the glue is liable to chill before this can be achieved. After cementing, Fic. 6, tie the two ends securely, and proceed to whip from end to end, using a piece of fairly strong twine, tied to a door handle, or some convenient fixture, and turning the spar by hand, keeping constant pull on the twine. The spiral formed by the twine should have about 3-in. or $-in. pitch. When whipped, the superfluous cement may be washed off with a sponge and hot water. When thoroughly dry remove the whipping and finish off the outside first with a scraper and finally with glass-paper, using a rotary motion, if possible. It is advisable then to French polish the spar to as it sounds; | great care has to be taken, or the should be left untouched, and as far as possible the hounds and other fixtures should be attached Fic. 9. over the joints. If, however, a fixture has to be made where there is no joint, a small diaphragm must be cemented in the correct position. After cementing together, as already described, the joints will have to be smoothed down with a file, but a slight amount of projection should be left where any attachments are to be made, as this prevents all tendency to slip. The ends should be plugged with wood and tapered off; the whole glass papered and French polished, as already described under hollow spruce spars. ; Hounds, crosstrees, etc., are made by hard September 19, Lor. . The Model Engineer and Electrician. soldering the loops and other fittings to a strap of thin brass, which is subsequently bent round the spar, and either clamped with small bolts and nuts, or tightly whipped over with fine, hard drawn brass wire, which is subsequently soldered together with soft solder and a soldering iron, avoiding too much heat or the spar will be charred, and become loose under the lashing. See Fig. 3, where A and B show crosstrees and hounds made 275 The spar must also be whipped at intervals of about 4 ins. where no whipping is necessitated by making attachments. _ I should have mentioned before that the mast rings must be placed on the mast before fixing the hounds, etc., as they are difficult to put on afterwards, and for the same reason it is advisable to have a few spare rings to allow for breakages. The rings are made of thin strips of bamboo wrapped round a wooden mandrel, a . c Ye 10 12 bt Pd ye rt 2415 t Scale for 10 melre 19 12 Sof 24 /ns 4 Scale for 12 melre / Pa F. \ / / S ov ® 7 Wo ae Be } \\ / \ \ SAIL AND RicGING PLAN. with clamping bolts, and C a fore spreader, with loop for jib halyards, made for whipping on, as described above. Paragon umbrella frame steel makes excellent crosstrees, spreaders, etc. Loops for sheets, halyards, purchases, etc., where not embodied in the hounds, can be made out of bent wire, with flattened bases, as in Fig. 4, A and B, and neatly whipped on with fine white thread. after first fixing one end in a saw cut, and clamping the free end, as shown in Fig. 5. The bamboo is then boiled for a few minutes, and then baked till almost scorched, after which it will be found to have taken a permanent spiral shape. The spiral is then cut up into rings, allowing sufficient to lap over; the laps are tapered off, cemented and whipped, and finally varnished. a brush, taking care that it does not run over the spar, and when thoroughly dry, the whole may be given two or three coats of copal varnish, applied as already described under “ Varnishing the Hull.” The bowsprit is scarcely worth making hollow, and as it will probably receive more bumps and strains than any other spar, it is advisable to make it out of solid spruce. The gaff jaws can be made conveniently, as shown First turn a groove in a piece of metal, so that the diameter at the bottom of the groove is a shade larger than the mast; then file out the groove as shown in Fig. 6a; cut out a bit of 30 S.W.G. brass, anneal thoroughly, lay. it over the | | | | | | | | groove, and hammer it in with a strip of lead | groove. Next bend a bit of the same brass round to form a conical socket for the spar to fit in, and | superimposed, so that it takes the form of the ie +4 finally bind the whole together, including two loops (one for the throat halyards and one to attach the throat of the sail), and silver solder together. a’ j 7 Finally trim off and polish. > The mast and spars being finished, the whipping should receive a coat of French polish put on with = | zi but require a little care. 4 The rings ate not difficult to make in this manner, in Fig. 6. September 19, 1912. The Model Engineer and Electrician, 276 i % v Nw 5 | pu | Ld J | steel wire is used throughout for the rigging, for the running fore stay, which should be of twisted brass wire, as even electro-plated music wire is liable to rust, and would cause nasty ironmoulds on the sail in time. “ Hercules unrustable sea gimp,” which can be bought at any fishing tackle shop for a few pence per yard, is excellent for running rigging where great flexibility is not required, and would answer perfectly for this stay, which was referred to last week under * Sailmaking.” It is advisable to carry a few spare shrouds ready made up with eyelets, each one coiled up in a separate envelope, so as to keep it ue ma 2 rs Yt | \ x La 23¢ | Lead | | | = y & = 2 3 4 iS) gos — | g : BY be | 1s. 6d. a dozen they can be replaced at a small – | up with eyelets strung with soft brass binding wire, which can be cut adrift when dismantling if there is any difficulty about tindoing it. _ Of course, except ie ; at Messrs. Melhuish’s, Fetter Lane——I believe they not -expense when rusted up. Personally, I prefer to use tightening screws, except for the fore and set being stays back bob stays, the shrouds and i ° ty | would be liable to rust; as, however, they cost e & | is that they are made with steel screws, ‘ ‘yh aH 3 | Excellent tightening screws are to be obtained are made for model aeroplanes. The only objection which =S ay | Fic. 15. § S. sl iad Sy oN q = = September 19, 1912. The Model Engineer and Electrician. from getting tangled, which steel wire is very prone slide, illustrated to do. Aluminium wire is not suitable for shrouds, etc., as it has a way of dropping apart when least 277 in Fig. 8, This is made to slide on a wire fixed at each end, like a horse, and clamped in any position required with an eccentric. This wire should be made about ro ins. long, and a bight expected. If steel wire is objected to, the next best substitute is hard-drawn brass wire. It is advisable to fix the eyelets in by taking a of the sheet passed through the loop on the slide, so that by moving the slide from one end to the other about 20 ins. of sheet is taken in. This will be ample for the fore sheet, but for the main sheet a couple of cleats should be provided, which will take up rather less than 20 ins. of line for each round turn; then any quantity of sheet can be paid out as required. It is useful to have a scale marked on the deck, so that the sheets can be set with accuracy, as required. lig. g shows a practical form of goose-neck. The only remaining fittings to be. described double turn of the wire round the eyelet, and whipping the short end with very thin brass or are the horses, which are provided with small spars Fic. pivoted at one end, and passing under the horse bar at the other end, with an eye at each end for the sheet to pass through (see deck plan). I believe this is the best type of horse, as it is practically impossible for the sheet or traveller to jamb over to windward. igs. 11-14 show bamboo spars to. copper wire, and soldering. The spare shrouds should be provided with eyelets at each end, as it is difficult to fix the steel wire directly to the hounds at the water side. The running rigging is best made of plaited tanned hemp fishing line, which can be completed. jibboom, for a week or so during wet weather, then thoroughly most of the stretch etc., it is are required. standing and total is taken advisable out of it, but for the string using wire if any long leads The outhaul is made in the manner shown in 7, of brass wire hard soldered, and it is advisable to have a few notches cut on the underside Fig. >) a | oe fore weight, running rigging, 9 3-16ths ozs. ; sails, j 7 =f Fie. 14. linseed oil, and In this manner to keep of 2 a dried, and then soaked in raw finally wiped as dry as possible. halyards, oz.; 22e- ¢ as short as possible, $ 3-16ths oz.; — i oa detail The weights are as follows: Mast, 34 ozs.; boom, 2} ozs. ; gaff bowsprit, 1 0z.; gaff, 1} ozs. ; bought for 6d. or 8d. per 20 yard hank. This should be hung out of doors, with a heavy weight attached, an “lig. 15 shows enlarged foot of jib. —_ i 58 ozs. Grand total, 14 ozs. 13 drs., for a 12-metre boat with 2,328 sail area. For a 1o-metre boat with 1,617 sail area = 10} ozs. If a spinnaker boom is used, it should be made of solid spruce, as its weight then will balance the weight of the main boom. I have omitted all mention of rudders and steering gear, as that is a question quite apart from model design, and is Ya Throat Halyard sufficient in i it purchase. itself to deserve au I Peak Halyards. YE i 5 Me. ul + 25¢—+—pyl -/9″: /q* Fie, 13. of the bowsprit, into which it will spring, thus overcoming any question of the outhaul halyards stretching. Common brass watch swivels make excellent snatch hooks for sheets, guys, etc., and bowsies are too well known to require description, beyond the mention of the fact that the circular type, cut off a piece of thin brass tube, are perhaps the easiest to handle with cold, wet fingers. The next fitting to be described is the sheet entirely separate article by someone who has had more recent experience than the writer. Judging from what I have seen in recent regattas and trials, there is still room for improve ment in this direction. Could a gyroscope be made sufficiently light for this purpose? On most ponds, something more than a rudder that will keep a boat true to the wind is required, and scope seems problem. to be the most likely a gyro- solution of the