2, 1908. - John-Tom Engine Plans

1 4 January 2, Model Engineer and Electrician. 7he should find a pleasure in acquiring mathemat-ical and scientific knowledge. He should have asufficient liking for working with tools to enable himeither to make machinery or apparatus himself, orto judge the workmanship of others who may becarrying his designs into practice. The training forsuch a lad should be a judicious combination ofpractical experience with workshop tools and pro-cesses and theoretical study. The latter ought toinclude practice in making engineering drawings andacquaintance with cost of materials and three broad kinds of engineering careersare open to a lad, and each is divided into a varietyof branches. Commencement is easiest when thelad leaves school, say at about the age of sixteenyears, without having entered any other becomes more difficult as age increases, thoughwith means a person may take up this occupationwhen he has reached years of manhood.

2 (To be continued.)The Junior Institution of attended visit of this Institu-tion was recently paid to Woolwich Arsenal,appropriately arranged to follow the strikingInaugural Address on Some Comparisons betweenFrench and English Artillery, which had beendelivered by the newly-elected President ( Canet), the eminent French Chief Superintendent of Ordnance Factories(Mr. H. F. Donaldson), received the members, andunder the guidance of the chief mechanical engineer(Mr. Douglas Heap) and other officials, several hourswere spent by the visitors in an inspection of theinteresting processes of manufacture involved inthe production of metal time fuses ; bullets for themagazine rifle ; siege, field quick-firing and machine-gun carriages : mountings for heavy ordnance ;woodwork for carriages ; small arm and quick-firingammunition boxes ; wheels ; heavy breech-loadingguns, including the hoops and tubes for operations were shown, and working modelsof breech mechanisms of heavy breech-loading process of wire-winding was also seen, and inview of M.

3 Canet s observations on that topic in hisaddress, attracted particular Chairman of the Institution (Mr. Frank ), expressed to Mr. Donaldson the members appreciation of the special arrangements which hehad kindly made for their reception, enabling somuch to be seen in the limited time at the ensuing meeting on January 8th, a paperon Recent Improvements in Electric ConduitConstruction is to be read by Mr. FitzRoy Roose,of the London County Council Tramways Recon-struction to The American Machinist, the firstattempt to establish iron and steel works in India has just been started by a rich firm in Bombay,supported by other wealthy individuals and bythe Government of India. The district in whichthe plant will be situated will be near Sini Junctionon the Bengal -Nagpur Railway, where there isabundance of water, and where iron ore, coal, andlimestone can be assembled at low cost of for a Model Motor FireEngine.

4 ( With Coloured Supplement.)---By FRANK selecting the above subject for the design of thisyear s supplement, the writer is assured of itsfavourable acceptance for two reasons-firstly,because of the enthusiasm displayed for the fireengine by classes of individuals ; and, secondly,on account of it being something comparativelynew in so far as model engineering is fire Engine --in its own way-is as fascinatingto the general public as the railway actual fire fighting the now popular motor enginehas come to stay, and it is thought that the designand construction of models of this type, althoughscarcely thought of yet by readers of ours, may develop an interest and popularity, at leastapproaching, that displayed in model has not been published until now a design of amodel of this class of Engine , although it must bestated that a few models of the old style, viz.

5 , horse-drawn engines, have been made and described in thesepages from time to time. By way of introduction,it is as well to study briefly the general principleadopted in the design. It may have alreadyappealed to the notice of readers that in generaloutline an effort has been made to resemble inminiature one of the now well-known Merryweathertypes ; although, so far as scale is concerned, ithas been found impossible to adhere strictlyon account of a great difficultyin securing the exactleading dimensions of the prototype-an obstaclewhich doubtless accounts for the lack of anyprevious designs of this nature. Generally, however,it is to a scale of 1-1/4 in. to 1 ft. An encroach-ment upon the proportional width of the enginehas been forced owing to the boiler space neces-sary to render the steaming powers of the location of the various featnres of an actualengine has been more or less , the tanks to carry the supply of waterfor boiler-feed are situated on either side of boiler,and rest upon the frame (the water is fed intoboiler at intervals, by means of a simple hand-pumpin the right-hand tank, the two tanks being con-nected by a small tube across the front of boiler).

6 The tank containing the methylated spirit forfiring the boiler through the five-wick lamp issituated as in the prototype, at the fore-end ofthe framework, under the driver s box, and betweenthe front pair of wheels ; the admission of spiritto the wicks is via an air-valve actuated by a turnof the small handle at the back of the driver sseat. Those who have studied the motor fire enginewill recognise that the position of Engine and pumpsin the design corresponds with that of the original,but the double-acting pumps are necessarily morebulky in proportion. There are two simple enginecylinders, each 5/8in. bore by 7/8in. stroke, and theslide-valves and eccentrics are placed betweenthe cylinders : the piston-rods drive the pumpplungers direct through the medium of the slottedcrossheads shown in the is thoughtthat the air-vessel, being of polished copper, willadd greatly to the attractiveness of the modelwhen completed, and for that reason it has not8 The Model Engineer and Electrician.

7 January 2, covered up by the wooden box arrangement,as in the case of many of the Merryweather classof Engine . A continuous jet of water of 9 to 10 be thrown by this is effected by a dual method, asfollows : To release the pump from the enginethe pump rods are unscrewed below the crossheads,and by means of a small clutch (to be subsequentlydescribed) a tooth wheel on the crankshaft is broughtinto gear with a similar wheel on a pinion the said pinion is also a grooved wheel, which,in turn, transmits the power by a gut band to agrooved wheel attached on the inner side of therear wheel, as indicated in the drawing. A drivingwheel is shown on one side only, and a band brakeoccupies the corresponding portion on the oppositeside.

8 Of course, a driver on either side would bemore effectual, in which case it is feared the bandbrake must be substituted for the block patternness, it is proposed to make it of aluminium-thiswill answer the purpose equally as well as heaviermetal. The dimensions given are finished cross members of the frame, it will be seen,are small pieces of angle brass attached to the sidesby means of small angle brackets and riveted asindicated : the cross piece, shown about midway,should be a casting. No great difficulty presentsitself in this piece of work, and by the time somehave completed it, the construction of a more in-teresting part will be given.(To be continued.)GAS FROM MINERAL experiments atthe Caledonian Brass Works, Barrhead, in con-nection with a patent for the manufacture of gasfrom refined paraffin, petrol or other mineral oils,have been continued with success (says the GasFig.)

9 OF MAIN FRAME FOR MODEL MOTOR fire Engine .(Scale : One-third full size.).rim brake,usual on horse-drawn vehicles, and,indeed, the writer has observed them on some ofthe earlier types of motor engines ; but of thismore anon. The principle of steering is copiedsomewhat, and is exceedingly simple, the frontwheels being actuated to the right or left by aslight turn, in the desired direction, of the hand-wheel, and clamped in any required position bythe small compass screw shown dotted in thelongitudinal elevation. Thus are the main featuresof the model subsequent issues details will be dealt withmore fully. For the present, drawings are givenshowing construction of the lengths of brass channel section should beobtained from any metal merchant.

10 The writer hasnot been able to procure the exact section-viz.,1/2in. by 3 nearest being1/2in. by 1/2 in.,which, being 1/8in. too wide, must be filed down,unless the builder of the model does not object tothe deep channel. One end of each length is to beroundetl off as shown. A casting will form thefront end of the frame, and, for the sake of light-Enginineers'Magazine). By the Bruce system ofmanufacture and installation it is claimed thatit is possible to obtain gas from refined paraffinor petrol at a cost of a IS. per 1,000 cub. ft.,and that the light, besides being less trying tothe eyesight, is twice as powerful as that ofordinary coal gas. The light is given off fromincandescent WRITER in a contemporary states that heexamined the envelope of a balloon which burstat the International Exhibition at Milan in 1906A number of spots were visible on the envelope,and at these places the material could be easilytorn, whereas at other parts it showed great resist-ance to tearing.