NOV 1962 - WorldRadioHistory.Com · 2019. 10. 23. · NOV 1962 7 TRANSISTORISED STETHOSCOPE HIGH...

NOV 1962

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November, 1962 NEWNES PRACTICAL MECHANICS AND SCIENCE 49

The FLAKEwith the FLAVOUR

It is much easier than you think to develop yourown films and this new UNIVERSAL tank from Johnsonsmakes it easier still. You only have to load the filmin the dark, the rest of the job-developing, fixing andWashing-is carried out in the light. Everything hasbeen designed for ease of manipulation and the tank isadjustable for several widths of film -120/620, 127,35 mm./828 or 16 mm. (5 feet.)With fully illustrated in-struction book. At yourdealers' now, 32/6.

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50 NEWNES PRACTICAL MECHANICS AND SCIENCE November, 1962

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PRACTICAL MECHANICSAND SCIENCEVol. XXX

Editorial and AdvertisementOffices

"PRACTICAL MECHANICS"George Newnes Ltd., TowerHouse, Southampton Street,

Strand, W.C.2.© George Newnes Ltd., 1962

Phone: Temple Bar 4363Telegrams:

Newnes, Rand, LondonSUBSCRIPTION RATES

including postage for one yearInland - - - LI 8s. per annumAbroad - - LI 6s. 6d. per annumCanada - - - LI 5s. per annumCopyright in all drawings, photo-graphs and articles published inPractical Mechanics" is specially

reserves throughout the countriessignatory to the Berne Convention andthe U.S.A. Reproduction or imita-tions of any of these are therefore

expressly forbidden.

CONTENTS

!'*..

Talking point ... 51 ' :..'N.S. Savannah 52Lathe gadgets SSA transistorised stethoscope 57Inflatable space stations ... 58Water powered microscope 60The Magnus effect ... ... 62Picture news ... ... 64Amateur climatological

station 66Space age metals ... ... 70High efficiency convector

heater 71Bush separating funnel ... 75Cars for a purpose ... 78Farnborough 1962 ... 80L.B.S.C.'s "Evening Star" ... 82A teaching board ... 85An economical set of punches 86Photographic dry mounting

87Flexagons 89Trade news ... 92Your queries answered ... 94

CONTRIBUTIONS t*.*.The Editor will be pleased to considerarticles of a practical nature suitablefor publication in "Practical Mech-anics"." Such articles should be writtenon one side of the paper only, andshould include the name and addressof the sender. Whilst the Editor doesnot hold himself responsible for manu-scripts, every effort will be made toreturn them if a stamped and addressedenvelope is enclosed. All correspon-dence intended for the Editor, shouldbe addressed: The Editor, "PracticalMechanics." George Newnes, Ltd.,Tower House, Southampton Street.Strand, London, W.C.2.

November, 1962 No. 343

TALKING POINTThe Planet Venus

IN view of world interest in the planet Venus, with spacecraftnow endeavouring to gather information of interplanetaryphenomena during a trip to Venus and in the vicinity of the

planet, it might be of interest to review what is at present known.Venus, our closest planetary neighbour, is in an orbit between

the earth and the sun. Travelling at a speed of 78,300 miles perhour it has a sidereal period (or year) of 225 days. Its averagedistance from the sun is 67,200,000 miles. During its normalcircular orbit, Venus comes within 26,300,000 miles of the earthat closest approach or inferior conjunction. At superior conjunction,or points at which the earth and Venus are at opposite sides of thesun, it is 162,000,000 miles away. Inferior conjunction occurs every584 days. As Venus approaches inferior conjunction, the U.S.spacecraft Mariner 2 was launched to intercept the planet three tofour months after launching.

One of the puzzling features of Venus is the changeable darkand light markings that appear on its cloud layer. Scientists havespeculated that these markings could be breaks in the cloud cover,but as yet there seems to be little evidence of any regularity.

One of the outstanding features of Venus is its brightness.Because it is close to the sun, and has a reflective cloud layer,Venus is the third brightest object in our sky, after the sun andmoon. Its reflectivity is measured about 60%, as compared to 70%for our moon. Because it was not observed throughout the night,but appeared in morning and evening skies, ancient astronomersthought Venus to be two bright stars.

Venus has been referred to as the earth's twin. It has anestimated diameter of 7,800 miles, as compared to 7,926 miles forearth. Also, it is believed to have a mass and gravitational fieldsimilar to that of earth.

Spectrographic studies (identification of materials by presence ofabsorptive features, lines or bands in the spectrum) seem to indicatethat Venus contains carbon dioxide, and nitrogen, but probablylittle free oxygen or water vapour. Measurements taken in theinfra red region of the electromagnetic spectrum indicate thattemperatures of -38° Fahrenheit exist somewhere in the atmos-phere. The micro wave regions, however, show temperatures of615° Fahrenheit at, or somewhere near, the surface. The surfacetemperature is still in doubt.

Scientists are not in agreement as to the altitude from whichthese temperatures emanate. Indeed, there is one theory that aVenusian ionosphere, with thousands of times the electron densityof the earth, gives the impression that the planet is extremely hot.Another explains that the high temperatures are due to the " green-house " effect in which the sun's energy is trapped between thedense clouds. A third theory holds that the surface of Venus isheated by friction produced by high winds and dust clouds.

Recent radar measurements suggest that Venus rotates at a slowrate, perhaps once every 225 days, which is the length of theVenusian year. This would mean that Venus always keeps the sameside facing the sun, much the same way our moon keeps the sameside facing the earth.

Maybe more positive Venusian information will be forthcomingshortly, if the U.S. Mariner 2 spacecraft completes her adventurousvoyage successfully.

The Dec. 1962 issue will be published on Nov. 30th, 1962. Order it now I



by Donald S. Fraser

N.S.Savannahthe first atomic merchant ship

MANY years ago when steam was the marvelof the age, a frail 320 -ton craft was the firstship to use steam in the course of an Atlantic

crossing. Her name was the Savannah. Sherelied on wood for fuel, but could only carry suf-ficient to supply requirements for four dayssteaming. The balance of the 29 -day voyage fromSavannah, Georgia, to Liverpool, was completedunder sail.

Today, 143 years later, another Savannah ismaking maritime history. This vessel is a12,000 -ton nuclear -powered passenger and cargoship. The first merchant ship of the atomic age.Using uranium -235 fuel, she requires only 1301bof it to travel 300,000 miles. Sufficient, in otherwords, to meet cruising requirements for three -and -

a -half years without refuelling. The new Savannahushers in entirely new concepts on shippinggenerally. At present, she is a "floating laboratory"for scientists, marine engineers, and all who " followthe sea ". While much has been learned from suchatomic vessels as the submarine Nautilus, differenttechniques are required to operate atomic surfacevessels. For one thing, a new -style seaman isrequired who must be a marine nuclear specialist.

The new Savannah will carry 9,400 tons of cargo,accommodate 60 passengers, and have a crew ofapproximately 100. Her speed is 20 knots sustainedsea speed. Her cost-including the nuclear pro-pulsion system-was in the region of 40 milliondollars. For the first 18 months at sea, most of thepassengers will be nuclear scientists and engineersstudying the operation of the nuclear reactor andpower plant.

The Savannah's nuclear plant, including the con-tainment and shielding, is located amidships. Thesuperstructure has been placed just aft of the

S. SAVANNAS

NUCLEAR POWER PLANT

Drawing of thenuclear plant ofN.S Savannah.Intense heat isproduced by fis-sion of uraniumin the reactorcore. Reactorcoolant is usedto generatesteam in heatexchangers,which thendrives conven-tional turbines.



nuclear plant to minimise shielding weights, and toavoid having to provide access to the reactor con-tainment vessel through the superstructure. Herpressurised water reactor is an advanced version ofthe type that powers the submarine Nautilus. Theprimary shield consists of steel with a lead tank ofwater surrounding the pressure vessel. The con-tainment vessel is made of steel plate, and thesecondary shield of polyethylene plastic, lead, con-crete and steel. Wood and steel, in alternatinglayers, act as a collision pad. The reactor system,containment and shielding have a gross weight of2,500 tons.

The whole reactor system of the Savannah com-prises, as well as the reactor itself, the coolingsystem, the steam generators, the pressuriser, andthe intermediate cooling, purification, control andinstrumentation systems; all of which are enclosedin the containment vessel which is 501 -ft long and35ft in diameter. The reactor core consists of anassembly of 32 fuel elements, each containing 200stainless steel tubes, lin. in diameter and filledwith uranium oxide enriched to about 4% U-235content. The pressure vessel is a 26ft cylindricalshell, 8ft in diameter, made of carbon steel, clad onthe inner surface with stainless steel, as are all thesurfaces exposed to primary cooling water. Thelevel of reactivity of the core is controlled by 21boron steel control rods. The primary system, con-sisting of the reactor with two main coolant loopsand two steam generators, operates at a pressure of1,750 pounds per square inch, at an average temp-erature of 508°F for the primary cooling water.Steam is produced in generators at 473 pounds persquare inch and 360°F at normal power, and pro-vides up to 22,000 shaft horsepower delivered to asingle propeller. Two natural -circulation typegenerators supply the steam to operate the pro-pulsion turbines and auxiliary turbine generatorsand the five -bladed, nickel -manganese -bronzepropeller is driven through double -reduction gears.

The Savannah under auxiliary steam power on hermaiden voyage to Yorktown, Virginia, for full -powerreactor operation and initial sea trials. These trials will

be continued for the rest of this year.

In this ship, 60ft of space is needed for thereactor and auxiliaries and another 55ft for thesteam plant and auxiliaries-all placed amidships.The containment vessel, however, and consequentlythe secondary shielding also, has its long axis foreand aft. This of course improves stability and helpsspace utilisation. By the same token, the Savannahdoes not have to carry ballast to maintain stability.In a conventional ship of the same size, only about70ft of the ship's length would be required for theengines and auxiliary plant.

The equipment designed to control the radio-activity created by the ship's reactor has undergoneextensive, and most extreme, tests. So much so infact that the carefully designed and constructedSavannah has been declared by experts to be theworld's safest ship. If America's atomic submarines,on their performances to date, are any criterion,this may well be so. It has been stressed that noseaport need be concerned about contaminationfrom the ship, as full precautions have been takenagainst all possible risks from collision or sinking.The escape of radiation from the nuclear reactor,although practically impossible, has been effectivelyguarded against. Any failure of any part of the ship'spower system, at once causes a complete shutdownof the reactor. In addition an automatic radiationmonitoring system keeps a constant check on theradiation intensity throughout the vessel. Anyincrease above the safety level will at once auto-matically cause the shutdown of the reactor. Evenif something happened to the reactor itself and itgenerated enough heat to melt its core, there wouldstill be no real danger. The containment vessel hasbeen designed and constructed to prevent theescape of both molten metal and radioactivity.

Personnel from the Savannah's engineering crewhave undergone extensive training. Subjects such



The giant, I05 -ton steel vessel isshown undergoing a pressure test.The vessel, 61 inches thick, 28 foottall and 9 foot in diameter, success-fully completed a hydrostatic pressuretest of 3000 pounds per square inch-equivalent to the pressure it wouldtake to shoot a column of water oneinch thick approximately 900 feet

morethan 2500 quality control inspections.

as atomic physics, electricity, mathematics,chemistry and health physics were part of theirpreparatory schooling. They then spent consider-able time at an Atomic Energy Commission site foron -the -spot training. There, working with scientistsand engineers of the commission, they took overthe operation and maintenance of an atomic powerplant. They also worked with a full-scale workingmodel of the reactor of the Nautilus. Havinggained a grounding in the fundamental principlesand operation of pressurised water reactors theywere then ready for duty aboard the nuclear -powered ship.

The Nuclear Ship Savannah-a joint project ofthe U.S. Maritime Administration and the U.S.Atomic Energy Commission-will eventually beplying trade routes and visiting ports all over theworld. She is expected to demonstrate the many

Shown here is the interior of the "atomfurnace" in which nuclear fuel will be "burned" to propel the N.S. Savannah.The precision -built, 105 -ton reactorvessel took over a year to build at theBabcock & Wilcox Company's big boilerworks. Because corrosion is a particu-larly pressing problem in nuclear reactorpressure vessels, the entire inner surfaceis bonded with a thin layer of stainlesssteel, by a special patented process.

advantages which nuclear power can bring toshipping and, which is probably equally important,allay the fears of those who worry about this use ofatomic energy.

The chief specifications of the N.S. Savannah areas follows:

Length: 545ft between perpendiculars;595ft 6in. overall.

Beam: 78ft (moulded).Displacement: 21,840 tons (full load at design

draught of 29ft 6in.).11,850 tons (light ship, at 18ft6in. draught).9,990 tons capacity (9,400 cargodwt.).20,000 S.H.P. normal.22,000 S.H.P. maximum.2025 knots sustained sea speed.746,200 cu. ft cargo capacity.

Deadweight:

Horsepower:

Speed :Bale cubic:

A Refresher Course in Mathematics By F. J. CammA helpfully written book covering a wide range and containing the distinctive featuresof the "Refresher Course" series-separate exercises at the end of each section toenable progress to be noted. 5th Edition 8s. 6d. by post 10s.

From Geo. Newnes Ltd., Tower House, Southampton Street,London, W.C.2


November, 1962

Part11

NEWNES PRACTICAL MECHANICS AND SCIENCE

LATH EGADGETS

KNURLING TOOL

KNURLING in the lathe is one of thoseoperations which is rarely absolutely essen-tial, yet is used surprisingly often once the

necessary equipment has been acquired.Its most obvious use is in the finishing of heads

of screws or nuts for finger adjustment, andseveral of these have already appeared in latheaccessories described in this series. Anotheruseful application is for increasing the diameterof a round piece which has been accidentally pro-duced slightly too small. If a shaft which should bea tight press fit in a wheel or ball race, for example,has been turned slightly on the slack side, a ringof knurling round the seating where the press fitis required will generally raise enough metal in aregular pattern to provide an adequately tight fit.This in fact, makes the knurling tool as near as oneis likely to get to the impossible " putting -on tool "!

Knurling used to be produced by presenting ahardened and patterned knurling wheel to the jobrotating in the lathe, indenting the work by theheavy pressure of the wheel. This imposes a loadwhich is best avoided in the comparatively lightlathes such as most model engineers would use. Amuch better procedure is to produce the knurledpattern by the use of a pair of matched wheels,mounted in such a way that the pressure required isapplied by a squeeze between the wheels, whichrelieves the mandrel and its bearings of all sidestrain.

The knurling tool shown works in this way,utilising a pair of wheels mounted in a holdermade up from mild steel bar. The wheels areavailable commercially in matched pairs, eachresembling a cigarette lighter wheel on a largerscale. They are dead hard, and the sharp ridgesacross them which form the pattern are angled oneach, to form a left and right handed pair. Theresulting impressed lines on the job cross over eachother to form the familiar diamond pattern.

The shank of the holder is a plain piece ofsquare bar of the maximum size that can be held inthe adjustable toolpost already described. It canof course, be equally well held in any other type oftoolpost. To one end of this bar is tightly riveted avertical piece on which the wheel arms swing. Ifthought desirable, a series of pivot holes could beprovided to allow the arms to be more nearlyparallel over a range of job sizes, although thesingle hole fixing for each arm as shown has workedvery well over a range of sizes from 0-21in.diameter.

By L. C. MASON

SS

The arms themselves are plain filing and drillingjobs from mild steel bar. Mark out one side and drillthe end holes ;in. B.S.F. tapping size, then bolt themarked -out side, via the holes, to the other blankfor that pair, keeping the two bolted together tillthe pair have been completely shaped. The crescentshaped bearing for the clamp bolt can either becarefully filed or machined out. In the exampleshown, the pair of arms was mounted in a machinevice and fed straight on to a kin. endrifill. Notethat the holes for the wheel pins are not on thecentre line of the arms. The heavy load is all oneway, so most of the metal is used to resist it. Thewheel pins are of silver steel, resembling partiallythreaded grub screws, the hole in the arm whichtakes the head of the pin being drilled clearancesize to take the plain part of the pin. The two sidemembers comprising each arm are held togetheras a unit by a round spacer between them, rivetedover into lightly countersunk holes outside and filedflush. Machine the length of the centre portion Ofthe spacers so that the arms allow no side play onthe wheels-which means of course, obtaining thewheels and checking with them before finalassembly of the arms.

Each pin should screw into the arm in the direc-tion in which the normal rotation of the wheel tendsto tighten it. As both wheels revolve in the samedirection and the arms are upside down in relationto each other, left and right handed arms are calledfor. For the same reason, a neater appearance

The double wheel knurling tool complete,



Peale.

5/1erad.

5/8"

1/4"B.S.F1

_ I

5/8-.1 PINCH BOLT.

1/4"aSE Riveted overeach side

1/4"B.S.F

3/4' 3/4" 71/2"

1/4"dia.ARMS 2pr. OFF L.d R. HAND.

43/4"

13/8" Drill 1/4"dia.

7//6!

I 1,0I3/16.1".4...?"

3/8","-

LFPER TRUNNIONfull.

J.3/16"

3/8"-t73/16"

3Arrad.

3/4"

1/4" BS.F

114"BS.F

r -11/4"1r- 4-1 1..-3./16"

WHEEL PIN (2 OFF 5/STEEL).

1A"B.S.FII 11 -

7/16"- h

LOWER TRUNNION.

3/4'1/8"'LL.3/16*

full.

11

a:\V41.) 7MA/if

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full.1raSF ..11/4 1/8"L.

ARM SPACERS 2 OFF PINCH Nur

results if the holes for the pivot bolts are alsohanded. The bolts are commercial l' -in. B.S.F. hex.head bolts screwed through the farther side of thearm and lock -nutted outside. By this means astiffly moving fit of the arms on the vertical bar iseasily obtained. There should be no side play atall. With the shaping of the arms complete, openup one tapping size hole at each end of the

The tool in use in the adjustable toolpost.

appropriate side in both arms to clearance size andtap the remaining holes *in. B.S.F.

The pinch bolt is a length of plain round rodthreaded *in. B.S.F. at each end as on the drawing;the fine B.S.F. thread providing maximum pres-sure on the knurls. The two little trunnion piecesthrough which the bolt passes are plain turningjobs, having the centre larger than the bearing endsto locate them between the side members of thearms and, in the case of the lower one, to providemaximum length of screw anehoragt for the bolt.Thread the lower end of the bolt for a length equalto the diameter of the trunnion centre and screw ittightly into the trunnion up to the end of the thread.The nut is a plain turning and tapping job fromhex. steel bar of a convenient spanner size across theflats. Alternatively, file up the hex. from roundstock to fit a handy size spanner. File a true flaton the upper surface of the top trunnion for thenut to bear on, which will avoid raising burrsthrough the pressure.

In setting up for use, adjust the opening of thearms for the job size and mount the holder in thetoolpost. If any width of knurling is required it isadvisable to clamp the tool by all the screws thatcan be brought to bear in the case of a four -toolturret or the adjustable height toolpost. Run theclamp nut down till both wheels just touch the joband adjust the wheel position by the cross slide sothat the wheel and job centres are in a straightvertical line. Position the tool along the job byusing the saddle. Put the lathe in slowest opengear and have the clamping spanner to hand. Asthe lathe starts, put the pressure on with thespanner really hard, giving it a generous half turnor so. If the length of knurling required is longerthan the width of the wheels, get the wheels cuttinga proper pattern in a ring of their own width, thenvery slowly feed along via the saddle. There is con-siderable resistance to a sideways feed of the wheels,so let the tool settle its own rate of feed or it willbe slewed round in the toolpost, resulting in aspoiled pattern.

The wheels shown are medium coarse. Theheavy initial clamping pressure is necessary to makethem cut a pattern matching their own. If thepressure is too light, they will cut a " fractional -pitch " pattern, very much finer than their own

(Continued on page 90)



A TRANSISTORISED STETHOSCOPEFOR ENGINE DOCTORSBY CLIFF MORGAN

THE need for such an instrument was broughtabout mainly because of the difficulty of try-ing to locate a hidden fault in a car engine

that defied detection by any normal means. Unlessthe engine was stripped down, diagnosis of the faulthad to remain by guess work. Stripping downwould have involved a lot of time, trouble andexpense, with the added chance that the fault wouldnot then have turned out to be where the local" experts " expected.

The simple instrument described on this page,can very accurately locate mechanical faults inmoving parts. So much so, that the stethoscopewas capable of finding, and following, a cracked ballin a slowly turning ball race of a roller press.

The probeThis is simply the case of a worn out ball point

pen, complete with the ink tube. Mounted on thetop of the case is a hearing aid earpiece. These canbe purchased in almost any radio shop that deals inkits of radio parts, and the price is reasonable, less

than 10s. The plastic earplug that is fitted to the ear-piece is taken off and the topof the pen is then drilled totake the spigot of the ear-piece, making a tight fit.

Drill to makeOa tight tit

Ball point pen

Listening probe

Leads to amplifier

Hearing aid earphone withearphone removed

If it is found that the stethoscope needs to beused in an almost inaccessible place, a length ofrubber, or preferably plastic, flexible tubing can besubstituted for the pen. The length of the tubingcan be as much as 14ft without loss of sound, pro-viding that the tube is kept free of kinks and sharpbends. Even then it will transmit a signal, but oflower signal strength. A case in point where theuse of such a long length of tubing was requiredwas on a fishing boat propeller shaft connectinggland. The space provided did not enable theowner to make a proper inspection of the sealinggland with the engine running so the flexible stetho-


CI 8pF, 3v wkg R3 6.8k ohmsC2 8pF, 3v wkg R4 6.8k ohmsC3 8p,F, 3v wkg TI 0C-71RI 100K ohms T2 0C-72

* Hearing aid earpieces, 50-10011 R2 IK ohm BI 3 volts

ICl



INFLATABLESPACE STATIONS

AFULL scale research model of an inflatablespace station was shown at the Lewi,s ResearchCentre of the National Aeronautics and Space

Administration, in August. The three -storey -highstructure, shaped like an American doughnut witha canister at its core, was designed and built byGoodyear Aircraft Corporation. Resembling a giantcircular tube, the space station is connected to itscentral metal hub by a tunnel -like rubber spoke.Constructed of rubberised fabric, the expandablestructure is a larger version of a 24ft model fab-ricated by Goodyear for NASA testing purposesat Langley Field, Virginia.

Mission requirements and human factors wouldset the criteria for the size of future versions, butit is understood that this type of space station

By our science correspondent

could be built 100ft in diameter, or larger. Oneof the major advantages of course, is that it can bepackaged in a relatively small container, thusreducing aerodynamic drag and instability. Bothof these factors present difficult problems whenbulky payloads are placed atop the upper stagesof booster systems.

In orbit, artificial gravity can be produced byrotating the station. This is accomplished by usingcompressed gas or solid propellant jets on theperiphery of the rubberised ring. Larger versionscould easily simulate lg, the normal tug of gravityat the earth's surface. The hub would remain atOg, and would be used for rendezvous docking,entry and exit, and for scientific experimentsrequiring no gravity.

The artist's drawings show two types of expandable manned space stations that engineers and scientists areclaiming might be established in orbit, using presently -available rocket boosters to get them there.

The three-man station (left), which is similar in appearance to a spoked wheel, is 40ft in diameter and has a 7ftcross-section. The ring and spokes are inflated from the rigid central structure which is fired into orbit by rockets.A capsule contained in the rigid section is provided to bring the astronauts back to earth at the end of their mis-sion.

The work area of the space station (right) is also expanded by inflation. The roof is raised and the "new room" isthen outfitted with equipment previously packaged in the rigid structure below. Fibres and woven metal cloth,impregnated with suitable materials to make them leak -proof and resistant to high temperatures, are availablenow for space usage and make these ideas more than a designer's pipe -dream.



!6,An engineer inspects the 30ft diameter expand-

able space station during inflation tests.

The expandable structure is designed to bepackaged around the hub during launching. Afterbeing lofted above the earth's atmospheric blanket,where there is little or no resistance, the stationwould be erected automatically by pumping air intothe circular structure. Once the space station hadbeen placed in an earth -orbit, the crew would beferried to it by the rendezvous docking technique.Housed in a Gemini -type (two man) or Apollo -type (three man) capsule, the astronauts would belifted into a similar orbit to hook up with thestation's hub. From there they would enter theexpanded ring. This area contains bunks, a galley,controls, communications and equipment for per-forming scientific experiments.

Power for the space station would be generatedby solar energy which could be converted directlyinto electrical energy. To return to earth, the crewwould re-enter the capsule and de -orbit to the earth'satmosphere in the same manner used by theMercury astronauts to make their landing.

The furniture is the result of space-age ingenuity.The built-in furnishings, made of Airmat rub-berised fabric, and supported from the sides of the7ft high ring, are inflated at the same time thatthe station is expanded. To conserve space, some ofthe furniture serves a dual purpose. For example,the air -filled bunks are easily converted into worktables. Chairs and desks are also designed to makethe fullest use of the interior space.

The problem of providing a varied, tasty dietfor the crew, with a minimum of preparation, hasbeen solved by using dehydrated foods encased inflexible plastic containers. Merely by the addi-tion of hot water to the packages, astronauts canhave breakfast of ham and eggs, luncheon ofchicken and rice, and dinner of beef and gravy.

Two engineers test the inflatable furniture in aquarter section mock-up of the 30ft space station.

Extensive experiments have been conducted totest the ability of the rubberised fabric to with-stand bombardment of micrometeorites. A 2in.thickness of foam rubber sandwiched between twolayers of fabric was peppered with pellets, at avelocity in the range of 20,000ft/sec. Engineersreported that the results showed that the expand-able rubberised skin was comparable to rigid typesof similar weights in its puncture -preventing ability.

This space station, the product of two years ofresearch, engineering and development by GACSpace Systems Division, could be the forerunnerof larger and more sophisticated versions whichwould serve as roadhouses for deep space explorers.

Don't forget to buy theDecember issue of our

companion journalPRACTICAL WIRELESS,price 2s., and receive your

FREE double -sided blueprintgiving details of the

Berkeley LoudspeakerEnclosure and The Luxembourg

Tuner.



MICROSCOPES are expensive to buy, withthe exception of those which are little morethan toys, but the unorthodox model

described here, although not very attractive inappearance, is both cheap and serviceable. Amaximum magnification of around 100 diameters isobtainable at a cost of only a few shillings. It isso simple that patience more than skill is requiredto construct it but, properly assembled, its per-formance will be found to match that of aninstrument costing many pounds.

The lensIn order to understand the principle underlying

the design it must be remembered that the earlymicroscope consisted of a small metal plate inwhich was mounted a tiny lens, often formed from adrop of molten glass. The idea of this unsophis-ticated model based on that primitive magnifier isto induce an ordinary drop of water to performthe same function as the early glass lens. Water,of course, both transmits and refracts light but,being a liquid, it possesses no inherent shape of itsown. The magnification which we can obtain byusing the refractive properties of water thereforedepends upon the shape which a drop of it can bepersuaded to assume. This, in turn, is determinedby the manner in which it is held.

The lens -holderThe drop of water is placed in a shallow depres-

sion which has a hole drilled through the bottom,this hole being small enough to permit the naturalsurface tension of the water to hold the drop intact.The more spherical the drop remains the greaterwill be the magnification obtained and the idealat which to aim is shown. The success of themicroscope depends largely on the care exer-cised in preparing the lens -holders, although somemagnification will result even from an indifferentmount.

General assemblyThe wooden frame presents no difficulties to

anyone possessing even a slight knowledge of wood-working and the fitting of the glass top (or stage)and the sub -stage mirror is obvious from the illus-

A

WATER

POWERED

MICROSCOPEBy W. R. SPENCE, M.A., B.Sc.

trations. It should be at 45° to the horizontal.although this is not critical. No dimensions aregiven as the microscope can be constructed to anysize desired. It is, however, important to checkthat the lens -holder can be brought right downuntil it touches the stage and the length of tubingto be used is governed by this consideration. Thediameter of the tube must also accommodate thefocusing bolt and its nut, which should be bushedinto it or soldered to it. Standard electrical conduitshould serve this purpose excellently. The onlytechnical part of the entire construction is theattachment of the rotating disc to the bolt head.The most efficient way of doing this is to drill andtap the bolt head to take an 8B.A. screw. Thedepth is not critical and washers may be fitted totake up any slackness.

Forming the lens -holdersIf segments are removed from the disc as shown

in the diagrams, these waste pieces may be put toexperimental use to discover the appropriate sizeof hole to be drilled. This will vary not only withthe type of material employed but also with thenature of the water supply. A depression not

The lens -holders and focusing mechanism.

The ideal lensformation.



A. 8 B.A. SCREW

B. WASHERS

C. FOCUSING BOLT

D. NUT

E. TUBING

Side view of the assembled lens -holdersand focusing mechanism.

exceeding kin. across should first be made with around -ended punch. A small hole should next bedrilled in the centre of the depression. A kin. drillmay be large enough to start with. The hole maybe gradually enlarged with a small rat-tail file ifnecessary, the optimum size being found by trialand error.

The metal disc need not be segmented if theconstructor wishes to dispense with preliminarytrial and error and a greater number of holes maythen be made in the disc to ensure that more thanone reaches perfection. In any case it is useful tohave slight variations in the holes and the punchedcups so that different " powers " of lenses may betried in a manner similar to that of a triple nose-piece in an orthodox instrument. 16 -gauge brass oraluminium will be found to be most suitable forshaping and is easily cut with tinman's snips or afretsaw. A medicine dropper is invaluable forinserting the water drop cleanly, for if the dropspreads the lens is useless.

Using the microscopeAs the lens is composed of water it will

eventually evaporate and, in the process of doingso, its shape (and consequently focus) will undergoa perceptible change. It is to counteract this, aswell as to allow for variations in the sizes ofindividual drops, that a focusing arrangement isnecessary. However, the range of effective distancebetween lens and object covers only a small fractionof an inch so the method of making the adjustmenthas to be fairly precise. A screw thread, as usedhere, is the most accurate means available, the pitch

governing the fineness of theadjustment which results from agiven movement of the focusingknob.

The disc, although firm, must stillbe capable of rotating easilybecause, when focusing, one handretains the segment in position overthe stage whilst the screw C isadjusted. Thus there is vertical butno horizontal movement of the lens.The constructor will soon develophis own technique for this andadjustment in practice becomesquite automatic.

The short -focus lens systemrequires the observer's head to beimmediately above the instrument,thus causing shadows in the areawhere light is most needed. The45° mirror does much to over-

come this but a universal mounting for themirror would be superior in permitting a moreprecise control of the lighting. If the mirror isreplaced by an M.E.S. bulb, operated through atransformer or from a battery, the illumination willbe more constant, especially if a polished reflectoris fitted. The light may also be placed above thestage for observations on opaque specimens.

Several models, constructed under the presentwriter's guidance, have been in use in a schoolscience department for several years without losingtheir initial efficiency.

The wooden body of the microscope.


AYOUNG Peruvian at Stanford University hasrecently proposed a new principle for verticaltake -off and landing of aircraft and has

revived interest in the Magnus Effect. This latestdevelopment in the search for a simple means ofachieving vertical take -off uses a rotating cylinderand hinged flaps and is claimed to be capable ofturning the entire propeller slipstream through 90°.Fig. 1 shows how this is achieved by a rapidlyrotating cylinder installed along the joint of a wingflap. The entire slipstream is turned down sharplyand flows along the surface of the flap to create anupwards thrust on the wing. At first sight thisappears to be impossible and in fact many aero-nautical experts would not believe it until they hadseen it demonstrated. However, this is really justanother application of the Magnus Effect which hasbeen known for many years and was first put topractical use by Anton Flettner in the 1920's. He

With flap loweredand cylinder rotat-ing slipstream isturned as shown.

With flap raisedand cylinder sta-tionary wing actsas a normal aero-foil.

Rotating cylinder

Fig.!

Rotating cylinder andflap combination for

V.T. of

Flap

THE MAGNUS EFFECTDESCRIBED BY

D. A. WATTused rotating cylinders to drive ships and to powerwindmills.

In order to understand exactly what the MagnusEffect is, let us study the forces acting on a rotatingcylinder placed in a moving air stream. Fig. 2a isa section through a cylinder stationary in a movingair stream and shows how the stream lines aredeflected around the cylinder. Considering next acylinder rotating in still air, the boundary layer ofair will tend to travel around with the surface asshown in Fig. 2b. If now the cylinder is rotated ina moving air stream as in Fig. 2c the velocity of theboundary layer at the top of the cylinder will bethe sum total of wind velocity and cylinder surfacevelocity, while at the bottom of the cylinder theresultant velocity will be the difference betweenthese velocities. Associated with the region of highair velocity is a low-pressure zone and, conversely,a high-pressure zone is created at the bottom ofthe cylinder where the air velocity is low. Thepressure difference between these two zones issufficient to cause a vertical thrust upwards on thecylinder as indicated. Reversal of either the direc-tion of rotation or the direction of movement ofthe air stream will cause a downwards thust on thecylinder. The thrust created in this way is sur-prisingly large and is the factor responsible for thecurved path of a spinning tennis ball or golf ball.This effect was first noticed in the 17th century inconnection with inaccuracies when firing cannonballs and was investigated by Magnus. Hedeveloped a theory to account for this phenomenonbut it has been shown by other investigators thatthis theory is not valid and that the true mathema-tical explanation is very complex. However, it isstill known as the Magnus Effect.

One of the most interesting applications of thisprinciple was in Flettner's rotor ships. Shortlyafter the 1914-18 war it became apparent thatsailing ships were becoming less economical to

Fig 2(a)

Reduced pressure

Fig 2 (b)

Resultant force

Fig 2 (c)

Increased pressure


I


operate than steam ships because of the time lostwhen adverse winds were encountered and becauseof the large crew required to set the numeroussails. Flettner reasoned that with such an abun- 8dance of free wind power available the discoveryof a simple and more efficient way of using thispower would give the sailing ship a new lease oflife. After various experiments using aerofoil -typesails, without much success, he hit upon the ideaof trying to utilise the Magnus Effect. Experimentswith a model in a wind tunnel were so promisingthat he was able to persuade his sponsors to agreeto convert a sailing ship, the " Buckau ", into arotor ship. The " Buckau " was a three -mastedtopsail schooner with auxiliary diesel -driven pro-pellor. She was 170ft long, 29ft beam and had adisplacement of 680 tons.

Further experimental work was carried out on ascale model of the " Buckau " to provide data onwhich to base the design of the rotors. These testsshowed that the ratio of peripheral speed of therotor to wind velocity is important and, as shownin Fig. 3, the optimum ratio is about 3.5 :1. Havingestablished this he was then able to determine thesize of rotor and speed of rotation required to givethe same thrust as the original sails. In fact hedecided to use two rotors each 60ft high and 9ftin diameter, rotating at 120 revolutions per minute.With these details determined he carried out moreexperiments on his scale model and compared therotors with the original sails. Fig. 5 compares theeffective thrust of the rotors with that of the sailsand shows clearly their superiority. Flettner hadobserved that the thrust on the rotor is not exactlyat right -angles to the air flow due to frictionaleffects, thus maximum forward effect on the hull isachieved with a wind at slightly more than a right-angle to the desired direction of motion. Fie. 4is a polar diagram showing how the forward effectdepends on the desired direction of motion. Theinner diagram of Fig. 4 shows the forward effectof a sail of the same projected area as the rotor.Except when travelling very close to the direction 2000of the wind the rotor is far more effective.

The " Buckau " was eventually converted into arotor ship, the rotors being arranged as shown inFig. 6. She was ready for trials in 1926 andexceeded all expectations, being faster than she wasbefore and able to sail much closer to the wind. Fig 5Her first commercial use as a rotor ship was tocarry a cargo of lumber from Danzig to Grange-mouth, near Edinburgh, returning with coal.Because of the success of the " Buckau " theTransportation Department of the German Navyordered the construction of another rotor ship, the" Barbara ". She was 1,700 gross tons, 300ft long,43ft beam and was fitted with three rotors each56ft each, 13ft 2in. diameter, driven at 150 r.o.m.by a 35 h.p. electric motor. She was also fittedwith a propeller and two diesel engines of 530 h.p.each.

The " Barbara " carried 3,000 tons of cargo anda few passengers and plied between Hamburg andItaly for six years. Operating experience confirmedFlettner's predictions and showed that the rotorship was a sound practical proposition. However,when the saving in fuel cost was balanced againstthe extra cost of installing rotors and maintenancecosts the rotor ship was only marginally better thana steam ship.


7

6

5

4

3

2

1

fLift10

Direction 9of motion 8to give

max. thrust6

Fig4 5

Polar 4diagram forequivalent 3sail area 2

10

9

5,000

4000

3000

1000

2 3 4

p/v

p. peripheralspeed

v -.wind velocity

Fig 3

5

IIIIIIPliiiii01 iId ill all

111rA II WOWM.IVANZETIA -II SA NMIIIIRV111MINIM5101EOMM

ill ralf.

WAWiii' FAN

1 2 3 4 5Direction of

relative wind Total thrust of 2 rotors(Peripheral velocity 50 mph

6 7\8Desired directi.00

of motion

1 i/Sai l

rigging0"

Thrust dr

e#0

-

. .e

eet,

.00,

re00 Fixed

rotor

, # ..00.100.10 20 30

End disc to prevent losses due to spillage of air overFig .6 `rotor arm I

r 74; \ IN Rotors ot- . 1 I \ I aluminium`alloy

The "Buckan" before and after conversion. (Laterrenamed " Baden-Baden".)


A


PICTURE NEWSFROM THE WORLD OF SCIENCE

A test for synthetic rubber

SCIENTISTS have found that a laboratory testof 20 minutes duration proved conclusivelythat the life of products made with a new

synthetic rubber can be increased by months, oreven years, it has been announced.

The test results, when projected to scale, compareclosely with those obtained from actual producttests.

After a 20 minute run at 180 rev/min, on ahighly abrasive wheel, small, tyre -like rubber rings,made of Butene synthetic rubber, are weighed todetermine actual loss from wear. The tests haveshown, according to Goodyear scientists, that 50-50blends of the new synthetic with conventionalsynthetics improve wearing qualities as much as50%.

Thousands of ring abrasion tests, with hundredsof compound variations, have shown the newsynthetic to be useful in numerous products subjectto hard wear.

The new polybutadiene type of rubber also im-proves resiliency, ageing and low temperatureproperties of rubber compounds. Even at lowtemperatures, Butene retains a high degree offlexibility. The unusual properties of the man-madematerial provide a degree of end product qualityimprovement unattainable prior to its development.

The persistence of the scientist is nearly alwaysrewarded.

Keeping an eye on the astronaut

"GIVE us the tools and we'll finish the job ",was possibly one of Sir Winston Churchill'smost famous remarks. The same thing arises

again, today, in the scientific world. Without tools,scientists would be sadly handicapped. However,judging by some recent space achievements, thetools required to " finish the job ", are very much inevidence.

Take the track radar, for instance, used in theMercury -Atlas launchings of American astronauts.It is one of the world's largest precision instru-ments and " locks on to " a signal from the soaringvehicle and relays a continuous flow of data, notonly regarding the spaceship's position, but regard-ing the astronaut's condition. It is a key part of theoverall General Electric radio -command guidancesystem which controlled the flight of boostersplacing John Glenn and Scott Carpenter in orbit.The tracker, located inside a radome, adjacent to abuilding housing related electronic consoles andcomputers, moves imperceptively on a 48in. dia.powered base ring that was machined to a toleranceof 50 millionths of an inch.

The words " science " and "precision " arc verymuch allied.


sk

Automatic welding for atomic useASPECIAL milling and welding machine for opening and re -closing welded containers for radio-

active material has been completed by Pye Limited, Royston, Herts., for the Belgian AtomicEnergy Authority.

The machine, designed for operation behind thick concrete shield walls, consists of a substantialfabricated steel base mounting a number of units which can be operated by Master Slave Manipulators(mechanical " hands ") to perform the necessary tasks. Facilities include a power driven turntable withvariable speed drive, a milling head, with vacuum swarf removal, an argon arc welding head witharrangements for automatic arc striking and tracking, and means for removing and replacing a screwedcap on the container if required. The machine is designed to accommodate containers up to 8in.diameter, with a maximum weight of 1,5001b. The units are readily adaptable for a wide range ofspecial applications.

Ease of servicing and simplicity of operation have been prime considerations and where possiblecontrols and drives are taken outside the shield wall. Master Slave Manipulators manufactured by PyeLimited are used to carry out operations where this has not proved practicable.

3,900 Watts under the sea

POWERFUL new sealed -beam projector lamps madeby U.S. General Electric

take to the water as easily as thisaqua -lunged beauty obviouslydoes. The 650W lamps (six arein use here) have operated, com-pletely submerged, up to 84hours, more than five times theirrated life. Ideal for underwaterphotography, they are equally aptfor the landlubbing amateur cine-photographer. This has notproved practical by othermethods.



AmateurClimatological Station

MAKING THE WIND DIRECTION RECORDER

By A. CrowfootNOW that your station is operating visually, it

is time to think about keeping records of thevarious phenomena that you have been

watching. Records give an hour to hour picture ofwhat is happening and enable the present to becompared with the past. Research is nearly alwaysbased on past facts, which are then applied topresent theories. As mentioned last month, if youhave purchased a thermograph and barograph, youwill have a station that will compare with almostany professional station. Remember though that astation of this nature is far too valuable to playwith. It must be worked consistently and methodi-cally. One reading lost or not taken will upset thewhole sequence, seriously reducing the value of theremaining records. Below is shown a suitable formof station log sheet on which your readings shouldbe entered. Completed sheets should be carefullyfiled and kept in a safe place so that they can bereferred to in later years. Much interesting informa-tion on trends in the weather can be obtained byplotting graphs of readings over long periods oftime. Even if you do not make serious use of yourreadings you will eventually be able to scientificallyprove or disprove the statements of your friendswho say it has been the wettest or driest summerfor years! One reading which is difficult to take iswind direction as this is continually varying and asingle reading is almost meaningless. Thus it is

well worth while to construct the wind directionrecorder as described below.

The wind direction recorderThis recorder is coupled to the centre of the

indicator, and is driven by the grub screw that locksthe pointer to the drive from the wind head. Theaction of this recorder is the reverse of mostrecorders in so far that the drum turns in eitherdirection without any lateral movement, whilst thepen traverses the length of the drum to give thetime indication.

First obtain a suitable size tin with the lid fittedin the end, not over the end. It should preferablybe 9in. long by 3in. diameter, as any variation fromthis size will mean that the other dimensions givenwill have to be amended to suit. This is not diffi-cult, neither will it make any difference to theeffectiveness of the recorder. A spindle, of ;in.diameter brass rod, 12in. long should be cut, andat one end a groove, in. deep, to clear ii in.wide should be turned, *in. from the end. Thisforms the locating groove. The spindle should thenbe mounted through the middle of the drum, greatcare being taken to ensure that the spindle is exactlycentral so that the drum runs truly on its spindle.

SUGGESTED LAYOUT OF STATION LOG SHEET

NAME ADDRESS LATITUDE

deg. min. sec.

LONGITUDE

den. min. sec.

YEAR

MONTH

daydate

wind

dir. vel.rain

pointevap.point

temp

wet I dry

rel.hum. bar.

cloud

type I heightREMARKS

Sun. 17th SE 15 nil 12 56 64 59 30.1 nim. 2500 cirrus at est. 10,000 ft



Overlap.

NORTH

N.E. 111111111111111EAST '' III , 1116; i,,,,

..........,_

11111o1111.11

11111ili

ber-1

idaqi ,111i11 I

SOUTH

SW

WEST

9-

5C

NW

NORTH

The lid of the drum should then be soldered inplact and the spindle also. The coupling unit fromthe drum shaft to the indicator shaft should beturned from a piece of lin. diameter brass rod. Theend should be recessed to ;in. diameter by in.long. The whole unit is lin. long. It should beslotted so that it will slide over the grub screw ofthe indicator pointer, which also acts as the drive.The centre should be drilled to fit on the drumshaft and should then be soldered in position.

Two supports should be made from fin. x tin.metal, either brass or iron. One end should bebent at right angles for lin. and should be drilledto take two No. 6 woodscrews. The vertical part iscut off 21 -in. above the base line. A slot, down fromthe top, should be cut in each to take the spindle.One should be cut lin. clearance, the otherclearance. The two supports are then mounted sothat they hold the drum by its shaft, the narrow slotengaging with the locating groove in the spindle.The base and the drum are then mounted firmly sothat the coupling unit engages with the directionindicator. To remove the drum, all one has to dois to lift the end furthest from the indicator,- thenslide it off. If your indicator grub screw is lined upwith the centre of the pointer, a line can be scribedalong the length of the drum in line with the screwto give the position of the edge of the paper. If youhave placed the grub screw elsewhere, turn thepointer and the drum to North, then scribe the linealong the top of the drum. Unless the paper islocated in the correct position on the drum you willget incorrect directions recorded.

Next make and mount the ink reservoir. Thisis a tank 10in. x lin. x lin. made from any suitablematerial. Tin is probably the cheapest and easiestto work. It must of course be watertight. It shouldbe mounted by means of flat strips screwed to theedge of a piece of ,-'in. thick wood, 10in. long. Theheight of the wood should be such that when

Clockmechanism.

'our marks,eta allowhours over run.

Clip.

Capillary tube

3,4" x1/8" brass.

4 B.A. screw

Wind changed to Ea*

Type of record to be expecte$from S.E.wind.

1/2"clearance

Hex. carrier

Vdriva fixed to-rninvitri."spindle of clock.

Spindle on centre line'pen drive.

Fixing block.

Packing block to suitsize of clock.

mounted, the top of the reservoir is level with thetop of the drum. Next make the pen drive. First,however, it would be advisable to obtain the capillarytube. This can be made for you by any scientificmanufacturing firm at small cost. It consists of afine glass tube, with a very minute hole rightthrough the middle. The tube is 2, -in. long, turneddown lin. at the intake end and +in. at the writingend. This end must be well rounded as the penmust write equally well in both directions. It is



DRUM TO INDICATOR COUPLING UNITBrass.

3/4"

Drum shaftSoldered to coupling

CROSS SECTION SIDE VIEW

27/2'

1/4"clearance.

lirclearance.-1

1/16

1

Drum support to freeend of shaft is thesame except that theslot is 1/8" clearance.

Drum support couplingend

Drive slot toengage grub screwOn indicator.

Free End ofdrum showinglocating groovein spindle.

DRUM SPINDLE AND SUPPORT BRACKETS

Yx1/6"dia. brass.

Pen drivesupport

Capillary tube

best to be guided by the makers as to the bestinternal diameter to be used. The line should be asfine as it is possible to get as the writing is con-tinuous and close. If it is heavy it will use fastoo much ink and produce a very blotchy record.

The pen should be mounted on a piece of lin.wide brass, kin. thick. This should be drilled at2lin. from the front to take the intake end of thetube. The brass should be tapered from the backto the front, or writing, end to help reduce theweight on the pen. The pen should be clipped onto the top of the carrier. The carrier in turn shouldbe soldered to a piece of hexagon rod, drilled in thecentre with a in. clearance hole. The hexagon rodshould be cut to lin. long, and should be drilled totake a 4B.A. screw as shown. This 4B.A. screw.fitted with a wing nut and having the thread turnedoff at the ends, is used as the drive screw.

The drive shaft for the pen should be made froma piece of lin. diameter brass rod, I lin. long. Eachend should be turned down to kin. diameter for adistance of lin. Half an inch from each shoulder agroove to clear kin. should be turned, to a depth of

in. Two mounting brackets, similar to thosesupporting the drum, carry the drive rod. Theheight of these should be such as to lift the penso that it has a very slight slope down to the paper.The rod should have a screw thread with a pitchof four threads to the inch for its full length of 9in.The drive for this screw must turn it at a speed ofone revolution per hour. This can be achievedeither with a clock mechanism or by means of asmall motor. I have found that the clock is verysatisfactory and easy to install. The glass and hour

Direction indicator pointer.

Wdia.brass rodsoldered in centre of drum.

&oove in spindleto lock drum in."---------..position.

Drum made from suitable tin.

3 dia.

1 Pen drive support.

Grub screwon pointer.

2"

3/4"x 1/8"

support.

WIND DIRECTION RECORDERGENERAL ARRANGEMENT, FRONT VIEW

Coupling unit.

34's 7/8" support.

3/4


November, 1962 NEWNES PRACTICAL ME

hand should be removed and the minute handshould be cut off close to the centre boss. A pieceof stout copper wire about 21 in. long should besoldered to the centre of the boss with each endbent at right angles for a distance of tin. as onpage 67. To the end of the screwed rod a piece ofthe same wire 2in. long should be soldered. Theclock should be mounted with the hand spindle inline with the screwed drive rod. With the pen inposition and the drive screw engaged in the thread,the pen will traverse the length of the drum. In 24hours it will actually travel less than the full lengthbut this over -run is advisable in case you are notable to change the paper at the right time. Therecord chart should be stuck on with a narrow strip

7/8-1

mulile111111111114ir 76

I/8" dia. drive rod.

4 threads per inch. .

CHANICS AND SCIENCE 69

of transparent tape. This must cover the joint asthe pen is liable to lift the paper if the drum isturning when the edge of the paper comes up to thepen. To remove the chart, cut along the tape witha razor blade. The chart should be drawn up asshown on page 68, with the hour lines the samedistance apart as the pitch of the drive thread, i.e.,lin. Do not expect your record to have a straightline unless there is a dead calm. The idea of thesmall vane on the anemometer head is to reducethe unwanted variations as much as possible, butthis is never fully achieved. An average is takenalong the length of the record. The chart showngives an idea of the kind of trace produced by aSouth Easterly wind, changing to an Easterly wind.

V2

ilMi1111111i1111111111

it '

CAPILLARY PEN DRIVE SHAFT DETAILS

WIND DIRECTION RECORDER

GENERAL ARRANGEMENT, SIDE VIEW

4 B.A. serow.Ink reservoir.

3,4"

Note:- A slight fall on pen. Capillary tube.21/4"

N.,

I" hex brassrod I PC long.

14"x 1"41/8"

c lips. 4 o ft

Drum

I/4"

Spindle.



SPACE AGE METALSARCHAEOLOGISTS have traced man's

progress through the various metal ages-those of copper, bronze and iron-since the

primitive Stone Age. Today the Age of Metals isslowly changing. Old metals are being replacedby new ones-Space .',ge metals.

There are now metals with peculiar electricalproperties such as germanium; new metals like theuranium family which produce radiation; andmetals with unfamiliar names-tantalum andmolybdenum, beryllium and zirconium, tungstenand vanadium-all of which resist the new andextreme conditions found both in outer space andin the heart of nuclear reactors. Even old metalslike lead are finding new uses, such as protectingus from radiation.

Today's space-age metals must withstand theheat and corrosion of the rocket fuel's flare andretain the strength and resistance necessary toperform usefully in outer space. One of the mostpromising of these new space -and -speed metals iscolumbium.

The first major production of columbium con-centrates, in North America, is being undertakenby the St. Lawrence Columbium Company at Oka,Quebec, Canada, where rock containing the metalis being broken with Canadian Industry Limitedexplosives " Amex " and " Cilgel B ".

Scientists, naturally, have put in a great deal ofmetallurgical research on columbium, the resultsof which have revealed the development of a newfamily of space-age alloys. Columbium, accordingto Westinghouse Research Laboratories, is a " key "space-age material. The alloys of no other metalshow greater promise as structural materials formanned space vehicles and nuclear -powered space-craft of the future, and the new family ofcolumbium alloys show the best balanced combina-tion of properties yet achieved with this importantrefractory metal.

High strength at high temperatures is attainedwithout drastic loss in the workability and the low -temperature ductility inherent in the pure metalitself. Both properties are crucial for space appli-cations. Without workability the fabrication of aspacecraft would be extremely difficult and costly;without low -temperature ductility the intense coldof outer space would render the structure brittleand unsafe.

Compared to most refractory metals the newalloys are light in weight with a density aboutequal to stainless steel. Yet they can operate attemperatures in the range of 1,800 to 3,000 degreesFahrenheit or about 1,000 degrees above theoperating temperatures of such steels. These arethe basic requirements of structural space metal.For example, light weight simplifies the launchingof a vehicle into space. High -temperature opera-tion makes possible smaller, more efficient enginesto power it, and permits its safe return to earthin spite of the terrific heating by friction with theatmosphere.

It was R. T. Begley, a metallurgist, headed by agroup of scientists and engineers from Westing-house, that developed the materials. The researchand development leading to the alloys was per-formed, in part. under contract with the U.S. Air

Force Directorate of Materials and Processes,Aeronautical Systems Division.Alloys to go into production

So promising are the properties of the family ofcolumbium alloys that three of them are beingplaced into pilot plant production. First to beproduced will be a columbium -vanadium alloycalled B-33. B-33 has moderate strength, iseasily fabricated and welded. It has unusualresistance to corrosion by liquid metals. Oneapplication being considered immediately for it, isin heat exchangers or radiators for spacecraft. Theonly means of getting rid of waste heat in space isby radiating it away at high temperatures. Whenunfolded in space such a radiator might be as largeas a football field. Only a strong, light, high -temperature and easily fabricated metal would befeasible.

B -33's corrosion resistance and its tendency notto absorb the neutrons which sustain a nuclearreaction also make it a logical candidate for keycomponents in nuclear -fired spacecraft and innuclear auxiliary power plants for space vehicles.

From the metallurgist's viewpoint the new familyof columbium alloys are remarkably easy to handle,it is understood. The processing of alloys of the" exotic " metals has always been something of ametallurgical nightmare. Seldom can high -temperature, high -strength alloys of metals such astungsten or molybdenum be treated by conven-tional techniques.

In contrast these new columbium alloys can beforged, rolled, sheared and handled directly, oftenat room temperature. Usually such processingmust be carried out at high temperatures and inan inert atmosphere or within the protectivecladding of a less active metal. The new alloysrequire such protection only during melting andhot -forming. Simple, inexpensive, well-knownprocessing techniques are used thereafter.

The two additional columbium alloys to be pilotproduced are B-66 (a columbium, vanadium,molybdenum, zirconium alloy) and B-77 (a colum-bium, tungsten, vanadium, zirconium alloy). Bothshow unusually high strength while retaining easeof working and fabricating.

The open -pit method is being used to mine therock which contains columbium. The pit goesdown to about 550ft (as the depth from the sur-face increases so does the proportion of pyrochlore,columbium -bearing ore, which runs somethingbelow 1 per cent.). First the ground is brokenwith great blasts of explosives and the large chunksof rock are broken up with pneumatic drills. Thisbroken rock is taken by truck to the crushingplant, where it is processed mechanically to isolatethe valuable pyrochlore. The remainder of therock is composed roughly as follows : calcite, 78-80per cent.; diopside, 6-10 per cent.; small and vary-ing proportions of apatite, magnetite, mica andpyrite. The rock is pulverised and the magnetiteremoved first by passing the wetted powderthrough a drum equipped with magnets. Thenflotation is used to separate the other minerals.They are passed through oils or liquids (such as



71

FOR a given electrical input the conversion ofpower to heat is the same for all heaters, butthe efficiency of distribution is an important

consideration. With convectors, which shoulddeliver a large amount of moderately warm air overa wide area (in contrast with the local intensity ofthe radiant heater), any heat that rises immediatelyon leaving the vent-a common fault-is wasted.A brisk, well -directed movement of air must begenerated for the desirable forward projection andthis should not be impeded by resistance at the vent.

The 2,000 -watt appliance described is unusual inhaving an inner chamber (Figs. 2 and 3) where ther-mal expansion compels the air to rise with growingvelocity. Further acceleration occurs in the tapered" throat ", a device used in every domestic chimneybut rarely found in electric heaters. Smoke testshave shown that the air sweeps round the bendwith a high velocity that carries it well forwardinto the room without the ceilingward drift evidentin some convectors. Enclosing this basic appliancein another casing causes further convection currentsto flow, as indicated by broken arrows in Fig. 2,transferring more heat to atmosphere and leavingthe metalwork cool enough to be touched safelyafter several hours' running at full heat.

Easy -to -work 20S.W.G. aluminium sheet can beused to make the inner chamber (mild steel ofthinner gauge if you are an experienced metal-worker). Assemble with round -head fin. No. 4,Type Z, self -threading screws, which are used likewood screws in screw holes 0.093in. diameter (No.44 drill) with clearance holes 0-116in. diameter(No. 32 drill). Fig. 3 illustrates the construction,as well as the dimensions and flanging details forthe front, back and two shaped ends. Formthe straight flanges by simple score -and -bend;clamp between shaped hardwood to hammer thecurved flanges over. Bend at the broken lines, thebottom flanges to be turned outwards and all othersinwards. Cut the rectangular hole in the left-hand side panel only. The front panel is 24in,long and is screwed to the flanges. The backpanel measures 24in. across to fit from flange toflange and its other dimension, nominally 204in.,should be checked by trial fit in case tolerance isneeded.

BY W. GROOME

The element carrier (Fig. 4) comprises two20S.W.G. sides with tin. flanges turned inwards,assembled to end insulators by No. 4B.A. round-head screws, nuts and lock washers. Six channel -shaped struts (three above and below) are screwedto the flanges to brace the assembly and to retainthe three intermediate insulators in their correctpositions. A bracket, shown in Fig. 4, carries thepilot bulb holder and should be screwed to thelower flanges to position the bulb (a 15 -watt,amber -coloured pygmy type) at the mid point.

All insulators must be of high-grade electricalquality asbestos compound, *in. thick; alternativelyyou may be able to obtain a bonded mica material.In either case the material must be heatproof andnon -hygroscopic, of good mechanical strength andhigh electrical insulation resistance. Asbestosbuilding board and ordinary plastic sheets are notsuitable. Ceramic bush insulation was rejectedonly because of the difficulty of obtaining smallquantities. Referring to Fig. 5, the left-handinsulator, measuring 4in. x 5in., is seen by the sameface visible in Fig. 4. Ignoring for the time beingthe heavy lines indicating the external wiring, drillthe two larger holes Ain. diameter and all others0.161in. (No. 27 drill) to clear 4B.A. screws. Theother end insulator measures 4in. square aridincludes all the holes that are fully included in thetop 4in. of the left-hand one, drilled in the samepositions.

Three identical intermediate insulators, 3-14in. x4in. with *in. x +in. cut-outs at the corners, haveholes of a diameter that will give adequate but notexcessive clearance for the spirals, probably ,'-in. tokin. These insulators are retained in the carrierby the channel struts.

The elements are ordinary 1,000 -watt electric firereplacement spirals. Connected in series pairs,their rating falls to 500 watts per pair, and whenstretched and exposed to moving air the pair willrun at " black heat ". Each series pair is arrangedto form four parallel lines along the carrier; foursuch 500 -watt banks give a total loading of 2,000watts, switched for alternatives of 500, 1,000 and2,000 watts. Altogether eight spirals are neededat a cost of about ls. each. They require simplepreparation. Put two nails in the bench about 18in.


, 4

Radius. 41/16"plus1,7r for flange.

3/8"

37/2"

27/2"

Note in LeftSide panelonly.

All flanges 1/4"unlessotherwise stated.

41/16'

2/4y

Front panel.

INNER CHAMBER.

20

''

5 11111:4111

1/"

3"

3/8

3/7613/16

3/43/4

3/844

3/4"

3/4"

5/8°

3/4

6"

A HIGH-Effte

375/16w

5/16°

L, 3 '15/16' -rri 3/4" 1./44. 3/4"

51/2"

J

'1?

OUTER CASING.

0

6 assembled.

19"

Cross-section of heater at thethroat, showing convection currents.

Cut -away sketch of inner chambershowing heater assembly in

position.

Part exploded view of elementsupports and pilot lamp bracket.

O Drilling and wiring drawings forthe end element supporting in-sulators showing connections to the

switches.

Exploded view of the outer casingwith inset showing details of the

front and back corners.

73


74 NEWNES PRACTICAL ME CHANICS AND SCIENCE November, 1962

apart and mark the mid -point. Stretch an elementspiral between the nails and retain by twisting thetail ends round the nails while you straighten equalturns each side of the mid -point to form a straightmiddle length of 2fin. Remove from the nails andstretch each half to a permanent length of 15in.This is shorter than the length as fitted in thecarrier because some reserve stretch is required toprovide tension. Treat all eight spirals in the sameway.

With the carrier assembled fit a 4B.A. xcheese -head steel screw to each screw hole in thetwo end insulators, each screw having two plainsteel washers under the head on the inner side, alock washer and nut on the outside, all left looseat this stage. Each half -spiral stretches from endto end of the carrier, passing through the inter-mediate insulators and anchored by the screws andwashers at the ends. Fig. 6 is a compressed scrapview with the intermediate insulators omitted sothat the run of the bottom element bank can beunderstood.

The first spiral has one end wound one turnbetween the washers at A and the screw and nutare tightened firmly. Stretching through the inter-mediate insulators, the spiral is secured by itsstraightened middle part to the opposite screw andwashers and continues to the next (opposite to B);then its remaining half stretches back to B at theleft-hand insulator. At all screws the wire shouldbe wound one turn between the washers and at theleft-hand insulator any excess ends of wire shouldbe snipped off. Tighten all screws and nuts firmly.

Use another prepared spiral in exactly the sameway at C and D to complete the bottom bank. The

carefully to avoid crushing or tangling and makesure they have enough tension to prevent drooping.To avoid dragging the entire spiral through all holesyou can begin by fitting the middle portion at theright-hand insulator and feeding each half to theleft for its end termination.

Bare 24S.W.G. copper wire connections must bemade on the outside of the left-hand insulator asindicated by the heavy free -hand lines in Fig. 5.Use additional washers and nuts for these connec-tions rather than attempt to cram more than onewire togethe.r. The three wires leading to theswitches are connected thereto later and should beleft about 8in. long for subsequent tailoring to meetthe switches fitted to the outer casing. These wires

must be protected by ceramic " fish -spine " tubularinsulators or fibreglass sleeving; those which lieagainst the end insulator can remain bare. Thepilot lamp holder, fitted by its shade ring to thebracket, is connected by flex passing through thetwo larger holes in the end insulator to the ter-minals P. Terminals L and N are for the line andneutral leads of the supply respectively.

Electric fire switches of 10 amp. rating can bebought from electrical stockists or sometimes verycheaply at surplus stores. The type required arebushed for one -hole fixing. Do not test the elementassembly before it is fitted into the convector asit needs the moving air stream to keep its tempera-ture down to black heat. Red heat would softenthe spirals and cause them to lose their tension andto droop. Fit the element assembly into the innerchamber or duct by screwing through at points thatavoid all risk of the screws fouling the elements.There should be a Ifin. clearance at each end andthe bottom flanges of the carrier should be 3in.above the bottom of the casing and parallel with it.Bring the three switch wires out through the rec-tangular hole.

The pleasant " custom-built " appearance of theouter casing is due partly to making the frame anexternal feature instead of concealing it. Identicalfront and back frames, illustrated in Fig. 7, havestraight horizontal rails of fin. x fin. xaluminium angle and curved sides of the samematerial. Although the curvature is distinct theactual " set " in the prototype is only fin. Thisslight bend can be made by hand over a woodenformer. Cut the angles 20in. long and trim, afterbending, to obtain the vertical dimension of 194in.

Assemble with screws, nuts and lock washers,heads countersunk and covered with metal filler ifyou dislike the round heads visible in the proto-type. The top panel (54in. wide) and side panels(6in. wide) should be tailored to suit the actualassembled dimension of your frames. Bend thesides more than needed so that they will pull backtightly to the frame on assembly. A slight set atthe top ends allows the top panel to make a neatflush lap. The small sketch in Fig. 7 shows howthe piece is clamped in the vice with two otherpieces of the same thickness. Tightening the vicedisplaces the top end by its own thickness. Cuttwo round holes in the left-hand side panel to suitthe bush size of the switches.

Frames and panels are put together with 4B.A.screws, nuts and lock washers, the heads to becountersunk and filled over with metal filler. Linkthe bottom rails by screwing two strips ofaluminium lin. x din. x 54in. across the casing atpoints 24in. apart and equally spaced from the ends.These are the strips (not shown in the drawings)on which the inner chamber will stand and they canbe drilled before fitting, two holes in each to line upaccurately with the holes in the bottom flanges ofthe chamber. All joint surfaces in this convectormust be clean and bright to ensure good electricalearth bonding. Cutting and bending details of thelegs, which are of angle section, are given in Fig. 7.Add corner stiffener plates inside the bends ifnecessary.

Use the inside edges of the frame as a markingguide for the front panel but cut fin. larger allround. Flange the top edge for stiffness and



November, 1962 NEWNES PRACTICAL MECHANICS AND SCIENCE

F.

ANYONE who has studied organic chemistrymust have used the conventional pear-shapedseparating funnel or its variants, the spherical

and the cylindrical funnel (Figs. 1, 2, 3), when effect-ing the separation of two liquids one of which usuallyis a solvent. It will also be remembered that if

LIGHT _4 HH

BYCOLIN SUTTON, B.Sc.

ether or some other volatile solvent was being used-as for example in the extraction of fats frommilk-pressure would build up during the processof shaking the liquids owing to the transfer ofwarmth from the hand to the funnel. This pressurehad to be released by placing a finger against thestopper, inverting the funnel and then opening thestop -cock to allow the vaporised ether to escape.

After a lapse of over 100 years this difficulty hasbeen overcome by a simple but ingenious modifica-tion known as the Bush Separating Funnel. Allthe normal liquid/liquid extractions that can becarried out in ordinary separating funnels can beperformed with the Bush funnel. The only modifi-cation is that because of the incomplete separationof the upper phase when taking it off by the sidearm it is not convenient to carry out the older typeof conventional extraction in which a lower phaseof large volume (e.g., water) was extracted a largenumber of times with a very small

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Transcript of NOV 1962 - WorldRadioHistory.Com · 2019. 10. 23. · NOV 1962 7 TRANSISTORISED STETHOSCOPE HIGH...