Popular Flying July/Aug 1957

T' ANNUAL GENERAL MEETING oF THE ASS.CIATI.N was held on 25th May at Londonderry House. About sixty members attended and the Chair was taken by our President, Mr. Peter Masefleld, who flew up from Bristol in a Iight aircraft especially for the meeting. The report of the Executive Committee to the members is published elsewhere in this issue and it is not our purpose in this leading article to comment at great length on the report itself save to say that the Association has indeed reached a state of development at which future progress can only be maintained efficiently by the employment of a full-time staff.

The problem of finding suitable staff is a comparatively easy one compared with the problem of finding the necessary finance to pay such a staff and a large part of the discussion period after the meeting was devoted to consideration of ways and means whereby this vital extra revenue could be obtained. We were gratified to note that the general feeling of the meeting was very much in favour of an increase both in Group and Individual Membership subscription rates. Unfortunately, however, the poor attendance did not give a sufficiently broad coverage of both Groups and individual Members to indicate whether or not this feeling was representative of the Association's members as a whole. The meeting, therefore, had to be content with expressing its intention both individually and collectively that ways and means of implementing their informal proposals should be examined by the Executive Committee.

The Executive Committee is therefore faced with the necessity to call a special general meeting once its proposals in respect of increased subscriptions have been crystallised and if this should be the case we earnestly hope that all our Affiliated Groups will send at least one

representative to the meeting to vote on this very vital issue. In the meantime we invite all Groups to express their opinion on a proposed subscription increase as we are anxious to obtain viewpoints before making firm recommendations to a special general meeting.

We do not wish to labour the point but a meeting at which only seven out of approximately ninety Groups are represented is not encouraging, but no doubt, as a member remarked from the floor, if a formal resolution from the Executive Committee doubling all subscriptions had been on the agenda we should have had a record attendance.

As foreshadowed in our last annual report Individual Membership has shown a welcome increase mainly due to the sales of working drawings of the Turbulent and Turbi aircraft. It is also gratifying to note the stimulating effect our new publication, PoPULAR FLYING, has had in bringing many of our old members back to active membership. Your Committee has felt, as have all members that the production of a real magazine would prove of tremendous benefit to the movement and, although only two issues have been produced so far, the effect on membership is extremely encouraging. The number of individual members is now 223, an increase of over 100 over last Year.

of the Executive Committee of the Popular Flying Association to the Annual General Meeting on Saturd ay, 25thMay, 1957

It is with pleasure that I once more present on behalf of your Executive Committee the eleventh annual report. Once again we feel that after hearing it you will agree that since we were last assembled here one year ago, the association has made great strides in its growth. We may now claim to be large enough to be a truly National movement that still continues to expand. Membership has again shown a most spectacular increase in the number of affiliated groups and the Association has now no less than 85 groups all on the active list. It speaks much for the soundness of the original conception of the group scheme when it is noted that 111 groups have been formed and affiliated since the foundation of the Association and of those that have disbanded for various reasons, less than a dozen did so after reaching the operational stage. In the last month about five groups have been formed and affiliated and the rate of increase shows no signs of diminishing at present.

It is interesting to note that this membership is world wide; our enthusiastic overseas members being mostly constructor members in the Dominions and Colonies and the United States. We are also proud to announce that the Ultra Light Aircraft Association of Australia has been formed mainly by the efforts of P.F.A. members and is now a rapidly expanding national movement, as is the U.L.A.A. of Canada. In both these Dominions examples of both Turbulent and Turbi aircraft are being built to drawings supplied by this Association.

On the technical side, a gteat deal of steady if unspectacular work has been accomplished by the Airworthiness Sub-Committee under Harold Best-Devereux; letters containing technical queries average about three a day throughout the year and all are dealt with and followed up by this very active sub-committee.

During the year design investigations have been undertaken upon further French designs as a result of which the Association will shortly be able to issue drawings of the Druine Condor, another excellent aircraft from the same stable as the Turbulent and Turbi. In addition a fourth design which is the subject of commercial construction has also been encouraged and helped by this sub-committee.

Liaison with M.T.C.A. and A.R.B. has continued to be the special care of this sub-committee and our technical relations with these two bodies continue to be entirely satisfactory- Internally,

Popular Flying, IulylAugust, 1957

however, the Association has had its problems on the design approval side and we record with regret the resignation of Mr. A. R. Weyl, head of our approved design team, and Group Captain Mole, who has always had a keen interest in the technical side of our affairs. Your Committee would like to take this opportunity of thanking both these gentlemen for their past support and efforts on behalf of the whole Association. We are pleased to welcome Mr. E. King who has been co-opted to the Committee as the new head of the design team.

During the past year there has not been a great demand on our Inspection Department which has continued, under the guidance of Captain Ayre, to prepare for the inevitable rush which will come with the completion of many amateur construction projects in the not too distant future.

The finances of the Association remain as ever under the watchful eye of our HonoraryTreasurer Colonel Preston. Thanks largely to increased group affiliations and the steady sale of aircraft plans, we show this year an excess of income over expenditure. This-whilst welcome-is by no means a cause for complacency for we still have large liabilities to the Kemsley Flying Trust on our balance sheet, and whilst the Directors of Ulair Limited have approved the balance sheet for 1956, they have taken note of the fact that the rapidly expanding state of the Association calls for the employment of full-time secretarial assistance if we are to continue to function efficiently. The present income is clearly not sufficient to support a paid staffand your Committee feel that with ever-increasing costs the time is not too far distant when the membership will have to consider very seriously the desirability of increasing both affiliation fees and individual subscriptions (the views of members on this point will be especially welcome in the discussion period which follows the normal business of the meeting). Colonel Preston will have a few remarks to make upon this problem later in the meeting.

Operationally the Association has once again had a good year and apart from minor incidents no serious accident to a group aircraft has

occurred during the past year. Over 73,000 hours have been flown by the groups. This total does not include hours flown by individual private owner members of the Association. The year which started well was marred in its conclusion by petrol rationing which reduced flying considerably during what has been one of the mildest winters for years. Happily this bogey is now once again laid and we can look forward to a season of increased activity.

No less than l0 groups qualified for the 1956 award of the Masefield Trophy and once again, thanks to petrol rationing, we have so far been unable to assess all the groups to date. Your Committee hope the results will not be long delayed.

We cannot pass from the operational sphere without mention of our 1956 Rally organised at Shoreham last June. From an operational point of view with an entry of over 30 aircraft what might have been a successful occasion was proved a dismal failure, entirely thanks to the appalling weather on the day of the Rally. We had the consolation, however, of welcoming over 100 members and friends to a dinner arranged on this occasion. Encouraged by this support your Committee have decided to try again this year, but, although our original date (today and tomorrow) was once again frustrated in the organisational stages by petrol rationing, arrangements have been made to hold the Rally at Sywell on the l4th-l5th of September. We hope on this occasion the weather will be kinder to us and that we can count on good support from the groups. Towards the end of 1956 public relations were put into the hands of J. H. Blake, already performing this function for the Royal Aero Club. At the same time he took over the responsibility for the Bulletin, which had been appearing with increasing difficulty in the past, owing to outside commitments of the last P.R.O.

A bulletin was produced within a few weeks, and a second, to a larger scale and size, came out in February. It was then decided that it should be possible to run the magazine on a proper monthly basis, and accordingly its production, and the collection of the necessary advertising

revenue to support it, were undertaken by Mr' Fryer, of Fryer's Advertising Service'

So far, at the moment when No' 3 is going to press, the reaction to PoPULAR FLYING has been extremely favourable; with the co-operation of all members in buying, writing for (and when possible advertising in) future issues, its success ought to be assured.

iublicity in this period has centred largely around the Turbi being built for 'This Week' at Bembridge. This aeroplane has been finished' and is now successfully completing its test flights' We are greatly indebted to the Royal Aero Club and AssJciated Rediffusion for the support which has made the venture Possible'

Finally, we will deal once again with the dayto-day -administration of the Association's businlss which has, as expected, increased enormously during the past year' As an example of what is to be expected a very short interview on B.B.C. radio by the secretary resulted in over 350 enquiries. A11 this type of work has to be dealt with in ever-increasing amounts and our part-time staff has reached saturation point' Yorr.Committeemust,therefore,facethisproblem in the immediate future' The Royal Aero Club has been of tremendous help over this problem in the past year-tYl.Yt cannot expect indefinitely to rely on the facilities so generously provided. In fact, it would be wrong to do sogratitude for the Royal Aero Club assistance ftust not blind us to the necessity of becoming self-supporting on the secretarial side as quickly as pot.iUt.. As we have mentioned earlier' additional revenue is the answer to this problem and waYs must be found to raise it'

In conclusion, your Committee feel that this is an opportune time to look back upon our achievernents since our foundation over 11 years ago in 7946, and to review our policy' After.11 yJurc of operation we can boast nearly 90 active ,mIut.d groups which have been brought into existence and guided in their initial stages by the Association.* We are proud of the records of these groups and their loyalty and support have been a constant source of encouragement to your Committee. Loyalty we are especially proud

of for, in spite of inducements offered by other organisations, not one single group has ever resigned to seek representation by another body' Wb ur. conscious that we are an association of amateur flyers and constructors, and we hope to continue to represent the amateur in all matters pertaining to his aeronautical welfare' We have pior..t.d the co-ownership group scheme and iruu. fought for and obtained valuable maintenance disfensations for group operators and for amateur constructors have achieved the permit to fly. We have also pioneered the group scheme within the R.A.F. and R'N'A'S' which continues to grow. Your Committee are prepared to coopelrate with all in the interests of light aviation as a whole, but we are jealous of the privileges which we have won for the groups' With your support we witl continue the good work of btirrgirg flying to the man in the street in as economic a way as possible and subject always to adequate safety standards with the minimum of r.d iape possible. The fight against red tape especially must be intensified; for far too long has the amateur aviator been supine before an ever-growing mass of rules and regulations which deprive him of his right to airspace' There is room ior all in the air if matters are viewed soundly and practically, and your Committee will continue to fight on your behalf for a fair share-if not necessarily a large share-of freedom in the air. The P'F'A' is a growing force in tight aviation today and it is more than time we in-creased efforts to safeguard our basic rights before it is too late' We look to the militant support of all our members on these matters'

* Mention must be made here of the splendid assistance which the K.F.T. has rendered to 59 of our Groups' It is fair to state that; without the wonderful support, very many groups would have had to wait far longer to become operational.

Popular FlYing, tulYlAugust, 1957

Down by the Glenside

This series of pictures shows the method adopted by thb. Rutherglen (39) Group to get their nearly completed Turbi wing out of the factory and on to its transporter for the journey to the hangar.

4 ,{

ffin" following extracts from the letter which accom- I ,Fanied the photographs give a quick picture of progress /at this most enterprising Group.

| 'Glasgow Corporation Transport Department were very helpful and laid on the overhead wire repair squad. We fed the wing out to them with 4" (repeat, inches !) to spare. And from then on it was easy.

'The Turbi is now up in the hangar along with the Auster. The Renfrew Group Chipmunk drops in once or twice a week to keep a watching brief on the new baby.

'The clubhouse is now complete and is really smart and any Group will be ushered in and entertained at one day's notice if they telephone Rutherglen I at least a day before.

'As regards our activities, we have worked every Saturday and Sunday since January completing hangar and clubhouse, so flying has suffered as a result. The Renfrew Group Chipmunk will be coming up to the hangar for the autumn and winter; so in less than a year the Group has produced one 50'square hangar for three aircraft.

'We are all looking forward to seeing all the Southern Groups at Sywell.'

NorB: in the caption to the photograph in the April issue, the Rutherglen aeroplane was incorrectly referred to as a Turbulent. 'Tain't so.' ED.

THERE LIES THE WING

HERE COMES THE TROLLEY

OUT POPS THE WING AND OFF GOES THE LORRY

Popular Flying, JulylAugust, 1957

THE AMATEUR AIRCRAFT CONSTRUCTORS GUTDE

ByArthurW. J. G. Ord-Hume - Part 4

Workshop Requirem ents-C ontinue d

Before the amateur undertakes the construction of an aeroplane there are two factors which he must consider. The flrst is where to build it and the second is what tools will he require for the task.

Dealing firstly with the question of a workshop, the average constructor will have to make do with a garage or perhaps a large spare room. It should be remembered that quite a large proportion of the work involved will be detail work and the manufacture of small parts for assembly and that in the early stages, at any rate, only a small space is needed.

However, once the constructor is at a stage where a fuselage or wing has to be assembled and finished, it is obvious that more space willbe needed.

For the Turbulent, a space is required at least twenty-flve feet long and eight feet wide as the wing is built in one piece. The fuselage, of course, may be constructed in a somewhat smaller space.

The ultraJight with a two-piece wing may be readily constructed in an ordinary garage.

The workshop will require a good sturdy bench for woodwork and metalwork. At least two trestles will be needed to support structures during assembly. It is recommended that trestles should be used rather than boxes since they are stouter and can easily be levelled and aligned.

For woodwork and gluing, the temperature and humidity of the workroom should be reasonably constant. This means that adequate ventilation must be provided without draught. Furthermore, freedom from damp must be ensured.

In the case of a garuge with a concrete floor, any gaps at the bottom of the doors can be sealed with strips of felt.

To keep the workroom at a reasonable temperature during winter, it is worthwhile investing in a 'black heat' electric space heater. This unit, mounted near the floor, will circulate warm air throughout the room for the consumption of very little current.

Whilst on the subject of electricity, it is important that any electrical installations in the workroom should be properly earthed. This is particularly so in a garage with a concrete floor. Should power be required for operating an electric drill or spray plant, make sure that there is a 15 amp. power point at hand. Under no circumstances should equipment be run from an electric light socket. Even lead lamps should be earthed through a three-pin power plug. If there is any doubt concerning the electrical wiring, consult the local electricity authorities who will send, free of charge, an inspector to check and give advice.

If a spare room is to be used for aircraft construction, take the precaution of checking to see that the completed components may be removed from the room either by window or door. This may sound elementary, but the author once saw a partially-completed ultra-light aircraft broken up as there was no means of removing it from the room in which it was built! Finally, the workroom should be well lit. In addition to adequate fixed lighting, a lead lamp is an advantage when one has to tackle a job in an out-of-the-way corner of a fuselage.

Tools for the job

It is not easy to list just what tools are required for the construction of an aircraft. Whilst an enthusiast may proceed with only a small selection of tools, it is desirable to have a reasonably larger selection with which to work. The right tool for the job means an easier approach to

Popular Flying, JulylAugust, 1957

the job-and that means a quicker, better result.

You can file away the bars of a prison window -but a decent hacksaw with the right blade makes it a lot quicker !

It is therefore intended to set out a list of tools which will suffice to do the job. All the undermentioned items are relatively cheap and are obtainable from all good tool stores.

Centre punch; cold chisel; small pin punch; large pin punch; scriber; pair of engineers' dividers; 12" steel rule, graduated in fractions and decimal inches; 50 centimetre rule (as alternative to above); straightedge, at least two feet long; medium sized ratchet screwdriver; 'Watchmaker's' long-shafted screwdriver; 4 oz. hammer (cross pane); I lb. hammer (ball pane); pair tin snips; pair long-nosed pliers; pair side-cutters; woodwork chisels f;" and 1|" wide; l]" smoothing plane ('Record' or 'Stanley'); spokeshave; six 6" clamps; selection of files (coarse, medium, fine and needle); tenon saw; hacksaw and selection of blades (18,24 and 32 teeth per inch); hand brace and set of drills; carborundum stone (for sharpening plane iron); assorted taps, dies, reamers and spanners (B.A. and B.S.F.); vice, 3" jaws for metalwork; vice for woodwork; 12" double-ended sail needle; pair large scissors; pair pinking shears.

A recommended addition to this-and one which will soon pay for itself in time and energy saved-is an electric drill such as the Wolf Cub. To this can be added the circular saw kit which makes a splendid unit for cutting small timber.

Furthermore, a fretwork machine, although not essential, could well be utilised for such jobs as cutting out plywood for wing ribs, bulkheads and so forth.

A small paint spray plant is also an advantage, but, since it may well represent a Targe outlay, it is not essential. A local garage may well agree to loan equipment.

A small, hand-operated guillotine will save much time in cutting out metal fittings.

We will now deal with some of these tools and their uses as applied to aircraft construction.

The centre punch is used in sheet metal layout work for marking, by means of a sharp in-

dentation, the centre of a hole. This indentation provides an accurate location for the point of the drill to start the hole. It is important to keep the point of the punch as sharp as possible to ensure maximum accuracy. The angle of the point may be between 60' and 90', the latter being a stronger point for use on steel.

The scriber and dividers are also used in sheet metal layout. The scriber is a conyenientlyshaped piece of hard wire with one end ground to a sharp point. Used rather like a pencil in conjunction with a rule, guide lines may be made on metal for cutting and so forth.

The dividers are used for describing arcs on metal as, for instance, the radius of the end of a fitting.

The cold chisel may be used for roughly cutting out a metal fitting. For general purposes the chisel is ground to a cutting angle of between 60' and 70'. The harder the material to be cut, the greater the angle and vice versa. The chisel should be as sharp as possible without being so sharp that the cutting edge dents in use.

The cold chisel cuts metal by means of shearing. The material should be clamped in an upright position in a vice so that the surplus material, i.e., the portion to be removed, protrudes. The chisel is held so that the lower angle of the cutting edge is parallel to the vice jaws. In this way, the chisel and the vice jaws act together as a shear producing a clean cut. To facilitate this action still further, the chisel should be held at an angle to the material so that a slicing cut results.

If the head of the chisel is held too low, the shearing action is lost and the material is bent or torn off. If the head of the chisel is held too high, the chisel will cut into the vice.

Pin punches are used for peening over the ends of bolts which have to be secured in this manner. By driving the end threads of a bolt down to the nut, the nut is effectively prevented from working loose. To do this, a heavy block is held in contact with the head of the bolt, the punch located on the end of the bolt. The punch is then struck several sharp blows with a hammer. The head of the bolt must be supported with

a block during this operation, otherwise the structure surrounding the bolt may be damaged'

The rule is a precision device used for measuring the distance between two points either in inches or millimetres. The rule is not a screwdriver, paintscraper or general purpose prodder' It should be kept specifically for the use for which it was intended.

Similarly, the straightedge should only be used as a straightedge. These two last mentioned tools are among the most misused in the workshop and cannot be expected to give accurate results if they are not treated properly'

An essential tool to the carpenter and aircraft constructor is the smoothing plane' For aircraft use, a good l$" ot 2" Stanley or Record brand with adjustable blade is recommended' This will cost about two pounds. To go with this, the constructor will also need a carborundum sharpening stone (a special flat stone is available with two grades for grinding and honing plane irons or blades) and a device for ensuring the correct honing angle for the blade'

To sharpen a plane iron, remove the blade from the plane by slackening off the spring wedge and undoing the large screw attaching the back iron to the blade itself. Using the honing angle device, the blade may then be honed on the "u.borrrrdum stone. Lubricate the stone with plenty of oil to prevent its clogging' If the blade is chipped or badly worn, it will be necessary

to regrind the blade. The honing angle device

can also be used for this purpose in conjunction with the coarser of the two sides of the stone' After regrinding, reset the honing angle device (the correct angle of the cutting edge of the blade is 40") and hone the blade on the smoother side of the stone. After this process, the blade should be stropped to remove burrs on the cutting edge'

In reassembling the blade to the back iron, care should be exercised to see that the blade protrudes not more than about ll32 of an inch from the tip of the back iron.

In use, avoid planing coarse wood or timber with knots in it-the blade will become blunt and chipped quickly if you do so. Keep your plane for aircraft woods. Always make sure that the blade is sharp. After use, either retract the blade by means of the thumb-screw or lay it on its side. Never lay the plane flat down for fear of damaging the blade. In all cases, before putting the plane away with other tools, retract the blade.

Never attempt to remove surplus glue squeezed out of a joint with a plane. Dry glue is very hard and should either be filed off with a rasp or preferably wiped off with a clean cloth whilst still wet.

To get the best out of a plane, never try to remove too much wood at one go. It is better to skim it off thinly with several strokes. Failure to do this will clog the plane, tear the grain of the wood and expend a good deal of energy on the part of the oPerator.

Mr. J. Endean of Johannesburg has sent us this photograph o! ltis Turbulent'in the white'. This evidence of activity in south Africa is most "n"ou,'iiiiil iiiiiitii qri,;';'i;;;i;;\s,;i' i; ;;;rs';-":i; ittt tt " targe number of ptans we have sotd abroad'

When scarfing up plywood in particular, it is important to remove the thinnest possible layer of wood at a time. This will give a good, clean sharp edge to the ply.

With a plane, you can always take more wood off: you cannot replace it if you have removed too much.

The spokeshave is virtually a smoothing plane made for planing curved surfaces. It is held firmly with both hands and drawn across the wood towards one at an angle of about ten degrees. This produces a slicing action, thereby giving a cleaner cut.

As with the smoothing plane, the spokeshave has a blade which is adjustable and may be set in any desired position. Do not use the spokeshave where an ordinary plane will do the job.

For clamping up glued joints, the constructor willfind the'G'clamp an invaluable accessory of which he cannot have enough. 'G' clamps are made in various sizes from one inch to eighteen inches in capacity. The sizes most used will be 4", 6" and 8". Clamps are rather expensive and, as a general rule, six 6" clamps should suffice.

In use, the jaws of the clamp should be prevented from making contact with the bare wood by means of pieces of scrap wood. It is possible to apply great pressure with a clamp and this will cause the wood fibres to be compressed and damaged if scrap wood clamping pads are not provided. For most purposes, it is only necessary to tighten the clamps lightly to apply the correct pressure for glue setting. Overtightening the clamps on a glued joint may well damage the wood and squeeze too much glue out of the glue-line.

The file is used primarily for metalwork, but it may be used with equal success on hard rubber, fibre, wood and so forth.

The most common files and those which are necessary for the amateur to possess are the flat, half-round, round, rat-tail and needle.

These flles are manufactured in various types of cut. The cut refers to the kind of teeth on the flle. The majority of files are double cut, having two sets of chisel shaped grooves opposed to each other diagonally across the faces. Single

cut flles are used mainly on wood or soft metals.

Double cut flles are provided in three types of cut: the bastard or rough, the second cut, and the smooth cut. The flat file is available with one edge devoid of teeth. This is termed the 'safe'edge which may be faced against the portion of the job which is not to be filed.

The file should always be used with a handle as, if the file should slip in use, the tang may well injure the palm of the hand. All files have teeth which point forward. This means that the file only cuts on the forward stroke. On the return stroke the flle should be raised to prevent blunting the teeth. However, when flling soft metal such as aluminium, thp file may be drawn back in contact with the metal as this will help to unclog any metal caught in the teeth.

As the blade of a file is hardened, it is very brittle. A file should never be thrown about, hammered, used as a lever or used as a hammer.

File with a steady, even stroke using as much of the length of the blade as possible. Maintain enough pressure to keep the file engaged in the cut to avoid damaging the teeth by slipping, clamp the material being filed tightly in the vice to avoid the material vibrating or the file teeth chattering in use.

To clean the teeth of a flle which have become clogged, use a file scratch card and brush in the direction of one set of teeth at a time. To prevent the teeth clogging when filing soft metal, rub chalk into the teeth.

When using a smooth file to finish a job, chalk in the teeth will produce a polished finish without scratches.

The hacksaw is used for sawing metal, fibre, wood and many other materials. It differs from the ordinary saw in that it has a replaceable blade held in an open frame. The teeth on the blade are smaller and are set somewhat differently to those on an ordinary saw.

To get the best results out of a hacksaw, care should be taken to select the right sort of blade for the material to be cut. Generally speaking, coarse teeth cut faster but are more easily broken than flner teeth. In selecting the right blade for the job it should be remembered that

at least two teeth should be in contact with the iob at any time. The more teeth in contact means less chip clearance and quicker clogging.

In assembling the blade to the frame, any one of four positions relative to the frame may be selected, since the blade is attached to a square shaft set in each end of the frame. For example, if it is desired to cut a two inch wide strip off a long sheet of metal, the blade may be fltted in the frame so that, with the frame horizontal, the blade edge is vertical thereby permitting the cut to be made without the frame fouling the material.

In all cases the blade should be assembled with the teeth pointing forwards. Tighten the blade flrmly in the frame to lessen the risk of breakage. In sawing, pressure should be applied on the forward stroke and the saw raised slightly on the return to avoid rounding the teeth.

Where space permits, use the whole length of the blade at about sixty strokes per minute.

If it is desired to make a wide cut in a piece of metal, it is possible to fit two blades into the saw at once.

The tools of fabric work and their uses will be dealt with in detail in a later article on aircraft finishing.

Engineering Drawings and their Interpretation

The engineering drawing, commonly referred to as a drawing or blueprint, is prepared by the designer to convey instructions and information to enable the constructor to make or assemble the detail concerned with speed and accuracy.

The drawing will show all pertinent dimensions clearly, thus eliminating the need for any calculation on the part of the constructor. It will also state the speciflcation, gauge or size of the material to be used, the type of flnish (..9., flle, machine, grind), the number required per assembly (e.g., six per aircraft) and the protective treatment to be applied to the completed part (varnish, paint, plate or anodise).

Therefore it can be seen that the drawing fulfils several purposes, each one assuring that the parts to which it refers may be produced exactly as the designer intended.

The illustration of a part on the drawing may notnecessari1ybefu11-size.Particu1ar1ywith large parts it is neither convenient nor practical for them to be drawn full size. It is often more convenient to make the drawing smaller by a stated ratio. For example, the part may be depicted one quarter or one half full size. This proportion of reduction is referred to as the 'scale' which is always indicated on the drawing.

If the part is drawn full size, the drawing states 'Scale:Full Size' or sometimes'Scale 1:1'. Similarly half size illustrations are sometimes i written 'Scale l:2' and so on. The scale of a I drawing is usually to be found in the title block, I that is the bottom right-hand corner, or prominently displayed elsewhere on the sheet.

Concerning the actual drawing, various types of lines are used for certain purposes.

The outline of a part, provided that it is visible to the observer in that view, is represented by a continuous solid line. Any part or recess not normally visible to the observer from the angle in question is indicated by a line of thin, short dashes. The centre line or datum line of a part is shown as a fine line or alternate long and short dashes with both its ends clearly extending beyond the object. This is further identifled sometimes by the symbol CIL or bears the selfexplanatory inscription 'Datum' and is the line from which layout dimensions are made. A

Historic occasion. The first test flight of G-APFA at Bembridge, Desmond Norman'up'.

Popular Flying, JulylAusust, 1957

continuous thin line is used for projection or dimensioning lines.

The draughtsman can illustrate a component in one or more of several manners.

For general work, the First Angle projection or orthographic projection is used which is arranged so that each view represents the far side of the adjacent view. This method consists normally of three views-the front elevation, plan and side elevation-to which may be added additional views such as base plan, rear elevation and opposite side elevation if they differ from the normal views given. The orthographic projection allows the clear and accurate representation of dimensions.

The Third Angle projection is a variant of the First Angle projection. This, too, is an orthographic projection but it is arranged so that each view depicts the near side of the adjacent view.

The drawing will not show an additional view unless it is essential to assist in its comprehension. If the detail consists of a complicated piece, an auxiliary view may be justified. This is a view looking on a portion at an angle other than ninety degrees. The angle of the view is generally indicated by an arrow or is drawn directly on the centre line of the portion concerned as shown in the normal orthographic view.

It is often desirable to show the section of a part. This is achieved by hatching at 45' to the edge of the drawing. Adjacent parts in section are defined by hatching at right angles to the main portion of the section.

A symmetrical object may be illustrated in both elevation and section by drawing one half as the outside view and the other in section about the centre line. An object may be sectioned at any convenient place to show detail which would otherwise be hidden. In this case, one portion of the detail may be shown as a section, or the section superimposed on the elevation.

Sometimes it is desirable to show a part pictorially by use of the Isometric projection method. In this straight lines are either at 30" or 90" to the horizontal. It should be noted that the isometric view illustrates 'the object in question without perspective.

Popular Flying, JulylAugust, 1957

There are basically three types of drawingdetail, assembly and general arrangement drawings. A detail drawing will show one separate part of a unit, for example, the rib construction for a wing. The assembly drawing will show the entire wing with the ribs and other details shown with their relative dimensions. The general arrangement drawing might show the entire aircraft in three or four views (as an orthographic projection) or might show the layout of a service or installation such as pitot lines in the wing.

Certain abbreviations are used on drawings. Below are listed those which are most likely to be met with by the constructor.

Annealedann. Diameterdia. or d Approved - appd. Materialmtl.

Centre lineCIL Not to scaleN.T.S. Chamfer -Chamf. Radius -Rad. or R. Countersunkcsk. Machine or grindf. Cylinder - cyl. Specificationspec.

The designer may call for two parts to be made from the information on the drawing, one left hand and one right hand, where the difference lies in the bending up of a flange or some similar detail such as the angle of a bend. He will therefore call for one pair'handed'indicating one left and one right hand piece.

Dimensions in inches are shown either as fractions of an inch or decimal inches as, for example, Lf," or 1.75". It is usual to take the smallest unit of measurement (one inch or one millimetre) and use it for all dimensions on the drawing. For example, a dimension might be 129 inches or 1,493 millimetres rather than the division of feet and inches or metres, centimetres and millimetres. It is practice to omit the 'inches' or 'millimetres' symbols from drawings where the same terms of reference are used throughout. Therefore we have 129 or 1,492. Reference to the title block will state what terms of referenbe are used on the sheet-inches or millimetres.

When a radius is shown, the dimension is written'R-+' or']R'where an inch is the term or reference. The same applies to the diameter of a circle which might be written as either 'D-105' or '105D' where the millimetre is the term of

reference. Diameters are also sometimes referred to by the symbol 95 which is used with similar notation.

There are two systems of production of a drawing. In both types the design draughtsman produces the original master drawing, usually in waterproof Indian ink, on either tracing paper or varnished tracing ctoth. This master may now be used to produce either blue-prints or dye-line prints. With the former the paper surface is entirely blue and the drawing appears in white or colourless lines, The blueprint is possibly the easiest type of drawing to read-the information contained on it is clearly visible even when the sheet is oily or dirty. However, exposure to direct sunlight or to water will cause the blue to fade, thereby making it difficult and eventually impossible to read.

The dye-line method of reproduction results in a white sheet upon which the information appears either in black or grey-brown. It is widely used in the aircraft industry in place of the blueprint.

In both cases, part of the technique of the printing of drawings from the master involves the washing of the print in water. Since paper expands and contracts with heat and moisture,

the drawing may only be used as an illustrated list of relevant data for the making of a part. On no account should measurements be taken directly off the sheet. Relevant dimensions will be written on it, thus eliminating the need for this.

Bearing in mind that paper is a poor medium for accurate drawing, the designer will often produce a drawing on a large sheet of metal or plywood. This is particularly the case in the aircraft industry as a drawing on metal may readily be cut out and used as pattern, template or part of a jig. These drawings on metal are often used to show the relative position of details in a section of an aircraft. For example, the outer skin of a bulkhead will be shown together with the inner skin and various internal members. One rnight describe these drawings as X-ray pictures of the portion in question. They are known as loft-layouts or loftings and are used in conjunction with detail and assembly drawings. They are reproduced photographically from a master tracing on to sensitised alloy sheets which are then developed.

With a little forethought and practice, the constructor should be able to interpret any drawing if he bears the foregoing points in mind.

M. Roger Druine (DRUINE),Frank Hounslow and Norman Jones with the Prototype Rollason Ardem engine. Productionofthese engines has now started.

M. Roger Druine (DRulNE)'launching' the Ardem (ARDEM) engine at Rollasons.

Popular Flying, JulylAugust, 1957

by Christopher Dearden PARTlOF3PARTS

Comeafill the cup, and in the flre of Spring The Winter garment of repentance fling: The bird of time has but a little way To fly-and 1o ! The bird is on the wing.

OMAR

I(HAYYAM.

Some thoughts on Amateur Designing

Start with the finished idea, and work backwards through a complete circle: such is the way of a designer. Indeed, the design of anything, whether it be an aeroplane or a sewing machine, is one vast juggle from start to finish-an endless compromise.

This little article is in no way intended to be a " textbook " on aeroplane design, for there are many such books. On the contrary, it sets out to say some of the things which are not in the textbook, and which may help the amateur designer to take the shortest route backwards through his complete circle.

Science is a very bright light that blinds too many people, so that the little, down-to-earth things are lost to their view. They become confused and drag others into the mire with them. Because it is the small and the obvious that keep the wheels turning, the following mundane words are offered, without apology, in the subdued light of some experience.

For as long as there have been aeroplanes there have been amateur enthusiasts (professionals are very rarely enthusiastic) discussing aeroplanes and scribbling their ideas on any and every scrap of paper that comes to hand, often at times when they are being paid to do something else ! Usually it ends at that, there being very many people who know what ought to be done but don't do it, a few who would but cart't, many who could but won't, and a few who are willing to have a shot. It is to this few that the article is dedicated.

The actual starting point of an amateur design is hard to deflne. The potential designers gravitate together and talk and scribble in the normal way. Quite suddenly they realise that

they have the makings of an aeroplane, and decide to do something about it. Then the sketches pile up and the very atmosphere is bursting at the seams from the sheer volume of ideas that come forth. Herein can lie a snag. This flood of ideas can go on and on and on until it drowns itself, unless someone takes the initiative and does something to check it. Here is lesson No. l. There must be a project leader. Obvious? Yes, certainly. But don't let the project drift too far before remembering just how obvious.

Not all the ideas can be used however good they may be, and sooner or later a line must be drawn. This is the project leader's first big job. It is also one of the most important steps in the aeroplane's life, since at this stage the aeroplane as it will be is really created. 'The finished idea' has taken shape; the goal has been set. In practice, the problem is not quite so great as it may seem on paper, for one enthusiast thinks very much like another on basic design, and so the matter resolves itself, under the steering hand of the leader. There is, inevitably, sometimes the bright Charlie who wants it to be a nuclearpowered Ornithopter, but he can usually be parked in a quiet corner of some distant hangar, and a high fence built round him.

At the same time as the above decisions are being made, the question must be asked, 'For what market is this aeroplane intended?', i.e., is it strictly a one-off special? Is it to be built in a factory, or home-built from a kit of parts? The outcome of this will materially affect the detail design, and therefore once the decision has been taken it must be adhered to, otherwise the result may be a something-and-nothing machine, an aeroplane too expensive to be 'popular', but not

comprehensive enough to be a luxury mount, too complicated for home construction and yet not well suited to factory production- To the rich man, the initial cost of the aeroplane is of secondary importance compared with operating cost. To the poor man, initial cost is of vital importance.

As work on the design progresses the project leader (Chief Designer) will have to spend an increasing amount of time co-ordinating the job, calling progress meetings as he thinks fit, and generally ensuring that everyone concerned is up to date with the latest information and data. The importance of this co-ordination cannot be over emphasised, even if there are only two people working on the design. In professional design offices a tremendous amount of time is wasted through misunderstandings and lack of liaison, even though these offices are to some extent organised. How much more careful must the amateur designer be then, for he can, usually, only meet his co-designers at evenings or weekends. Maybe Henry is designing the control system while George is doing the fuselage structure. Each makes a very small alteration to his layout-'Too small to be worth mentioning'and so each goes his own blissful way, until

! This sort of thing can and does happen. It need not, but it does. The sceptical may sneer at this-until it happens to them. Ideally, the whole aeroplane should be designed by one person, though this is very seldom the case, but the better the liaison the more closely is this condition approached.

No hard-and-fast rules can be laid down as to the sequence of design work, because in reality so much needs to be done simultaneously. For example: the centre of gravity position cannot be fixed until the G.A. drawing is finalised, any more than the G.A. drawing can be finalised until the C.G. position is known. At this stage a lot of intelligent guessing has to be done, working to and fro between the various aspects until the results agree--a vast jungle, an endless compromise. The following sequence is offered as a very broad and flexible guide to the stages of an amateur design:-

1. The idea.

2. Initial discussions and sketches.

3. The major decisions:Choice of engine, Preliminary weight estimate, Choice of wing and tail sections, Main dimensions, areas and loadings.

4. Further, more accurate sketches to determine the actual shape of the aeroplane, and to investigate the basic structure. Specification and G.A. sketches. Fixing of 'target weights' for major components.

7. Preliminary C.G. estimate.

8. Determination of flight loads. Basic stressing.

9. Finalised G.A. drawing.

10. Geometry drawings.

11. Detailed layout and mock-uP.

12. G.A.'s of major comPonents.

13. Detait design and stressing.

14. Detail drawing.

15. Performance calculations.

The performance calculations have been put last because they do not constitute an essential part of the design programme, but if the design has to be'Sold'to a sponsor, then they will probably be required round about the specification stage.

Overlapping of the various stages will occur right through the design as will detailed weight and C.G. checks. It may, in fact, be possible to start construction of the airframe at 11 or 12. Provided that the G.A. and geometry drawings really are finalised it is a good idea to get construction started early, because a gteat deal of time can then be saved on the detail design of some parts by making them to fit the aeroplane, then measuring them up and drawing them afterwards. This method is not often employed by the professional because he is burdened by people who are more interested in building personal empires than aeroplanes. He has to sort out all kinds of niggling but essential details on the drawing board, sometimes for an aeroplane that he has never even seen at close quarters-a ludicrous and grossly inefficient system. The

Popttlar Flyittg, July Ausust, I 957

5.

6.

amateur is, as a rule, in the much more fortunate position of being able to get to grips with the aeroplane without starting a political foray.

Designing parts 'on the job' does not in any way imply a slap-dash approach to the problem. Far from that, it is an eminently practical and sensible way of doing things and generally results in a better, neater design. The amateur just cannot afford to be slap-dash. The hand of officialdom is already against him and the hand of public opinion is not very far behind. It does not need many of his aeroplanes to come to grief for the dog to be given a bad name, or even outlawed completely. It does not matter if it can be proved conclusively that the design is entirely sound, the bad name will stick. If the decision has been taken to design for the 'HomeConstruction' market the designer must consider something more than just soundness. A design can be absolutely sound but very critical. That is to say, it can be structurally and aerodynamically near the limit, making it a fine flying machine while everything is perfect, but leaving very little margin for error in either construction or operation. This may be all very well for an aeroplane assembled in elaborate and expensive jigs at a factory, and flown only by experienced pilots, but although the home constructor's work is subjected to rigid inspection, the same degree of accuracy just cannot be counted upon. The designer must, therefore, aim to produce an aeroplane that will be safe and easily managed by a learner pilot, even if it has not been built absolutely 'spot on'. (It is truly hoped that the gallant band of home constructors will not take offence at the foregoing remarks, but such things must be faced.) Even so, the designer must see to it that his machine is 'Crash worthy', giving reasonable protection to the occupants in the event of an unintentional landing, or for that matter an intentional one that goes awry. Almost any aeroplane accident will get publicity, but dearest of all to the heart of the Press is the fatal accident-thus would the dog's name get even worse.

Designers should be dreamers, for out of their dreams comes the fibre of the brutal truth. That

Popular Flying, JulylAugust, 1957

the whole truth has yet to be found is a familiar matter of fact. The direction in which to look for it is a matter of opinion. It is for the individual designer to decide which lay-out points the right way. Alternatively, he may choose to follow the demands of the market, which will quite certainly point in a different direction altogether! At all events the author will try to avoid biasing the reader in favour of any specific layout, but since any discussion or argument must have a line of reasoning from which to spread itself, the single seat, ultra-light monoplane for home construction will be taken as that line.

How few enthusiasts could honestly say, or would want to say, that at some time or other they have not given themselves up to daydreaming and doodled something on the lines of Fig. la?

Of course, such an aeroplane is perfectly practical if it is to be produced in hundreds at a factory, or in the other extreme if it is to be made as a one-off special by some super-enthusiast. Double curvature is easy on the eye and easy on the airflow, but it can play havoc with the budget. These curves can be produced by hand, but it is rather beyond the skill of the average potential homebuilder to do so, and the designer must consider the average constructor if his aeroplane is to be marketed for home building.

The other methods by which double curvature panels can be made are pressing and stretchforming. Both of these require tools, the design and manufacture of which may well cost more than the aeroplane itself. This is quite reasonable in the case of hundreds or thousands of machines being made in a factory, for the initial financial outlay is more than recovered by time saving in production, and by the selling price of the finished product.

The amateur must face the brutal truth.

The choice of engine is one of the most vexed questions in the ultra-light camp, because in England there is virtually no choice. The designer must look elsewhere for his hope as well as his glory. From the purely theoretical point of view, an engine of l5-20 h.p. should be considered as the absolute minimum for single-seater types (this does not include'powered sailplanes') while

30-40 b.h.p. is a more realistic minimum, to give reasonable climbing performance. For twoseaters, the figures should be about 25-35 b'h'p' absolute minimum and 50-60 b.h.p' practical minimum. Under the ultra-light design requirements a maximum of 75 b.h.p. is allowed' A possible solution to the 30-40 b.h.p. engine might be found by modifying a 650-c.c. motor cycle engine to aircraft standard and driving a layshaf,t mounted airscrew via a chain and sprocket reduction. There is doubtless some regulation somewhere to prevent it being done now, although such a thing has been known in the past'

The initial weight estimate can only be based on previous experience, but if, as is probably the case, the' amateur designer has no previous experience, hp can look up the figure for as many similar types as possible and arrive at a faitly accurate answer. Some elements of this weight will already be known, e.g., Engine (probably about 130 lb. for 35 b.h.p.). Pilot, 180 lb' is a standard flgure. Fuel at 7.251b- per gallon' There will also be other standard parts such as wheels and instruments of known weight. Also any designed allowance for baggage. This leaves the

actual structure weight to be estimated. A fuselage weight of one-twelfth of the all-up weight, and a wing weight of 1 lb. per sq. ft. of area will not be very far out, while the rudder can be expected to weigh about 3.5 1b., and so it goes on. If at the end of all this his component weights add up to equal the estimated all-up weight, he is extremely lucky ! If they do not, he must work back through the variable items and eventually arrive at 'target weights' for the main components. These weights will be used in the estimation of the C.G. position and must thereafter be strictly observed in the detail design stage' The tail end of the aeroplane must be looked alter particularly, because a pound or two adrift there, either plus or minus, will have a relatively big effect on the C.G. If there are any serious discrepancies in this respect, they can, and sometimes have to be put right with ballast-but it's a very nasty thing to have to do. As a rough guide, a single-seat machine may be expected to weigh about 600lb. all up and a two seater about 1,100 lb. Notice how the addition of 180 lb' in the form of an extra body very nearly doubles the all-up weight. lTo be conrinued)

THE NERG SPECIAL by Your Special

Correspondent

A person who has found his own solution to the problem of a really cheap 'bui1d-it-yourself' aeroplane is Mr. Fred Higgins of Lesser Nergon-the-Tripe, Suffolk.

Mr. Higgins, who is an assistant knap faggler employed by the British Steam Bicycle Company, states that his aeroplane, the Nerg Special, cost only f,7 8s. 4d. to build. This includes the cost of the engine-a new 1.2 c.c. Korffan Schpetta with alloy crankcase. No instruments are fitted in the Nerg Special in accordance with Mr. Higgins' contention that after all they are only an added complication and serve only to distract the attention of the pilot. The wheels, Mr. Higgins tells us, are borrowed from the chap at Pinner who builds aeroplanes.

Mr. Higgins, known to allhis friends as'Fred', read how our opposite numbers in America made their machines out of junk found on aircraft scrap-heaps. He therefore explored the Lesser Nerg Council rubbish tip and, combining his flnds with a not inconsiderable amount of

Popular Flying, JulylAugust, 1957

ingenuity, produced this remarkably clean little machine.

We congratulate Fred Higgins and wish him all the best with his praiseworthy effort.

Fred Higgins, Erq., Lesser Nerg-on-the-Tripe, Suffolk DrlR SrR,

We are most interested in your mechanical aerodyne and would like further particulars.

Please note that we shall require certain guarantees before issuing any Permit to Fly; the machinery must be inspected by the Airworthiness Sub-Committee, plans submitted to the Committee itself and notiflcation made in writing to the R.S.P.C.S.M.A.E. Failing this, a substantial cash payment to the secretary will secure a permit without delay.

Furthermore, I am directed to inform you that in view of the second-hand nature of certain components, e.g., the rudder, on this aeroplane, certificates of airframe hours and checks undergone must be provided by the previous ownersin this case the L.N.o.I.T.U.D.C.

Yours faithlessly, J.

PUDDLEDUCK, for P.F.A.

Porsche Airqaft Engine

The following description of the Porsche aircraft engine has been received from the company and is reproduced here as being of interest to mony owners

The Porsche Company has now developed an aircraft engine and is proud to present it to the flying public alter having successfully passed the dynamometer tests of the Official German Aviation Research Centre in Brunswick'

We must stress particularly that the testing specifications and procedure of the German Aviation Research Centre are based on those of the'British Civil Airworthiness Requirements' which are among the most rigorous in the world and therefore assure the certification of the engine in all countries.

The Porsche engine completed these severe tests-which require among other things an endurance run of 150 hours-so that the test officials were able to fix the overhaul period at the comparatively high level of 600 hours'

This clears the way for the engine to go into quantity production which will not only fill a very vital gap in the European market but will allow the Porsche Company to present a new engine of sound design and many noteworthy features not offered by other engines in its class to the small plane designers and flying enthusiasts throughout the world.

General DescriPtion

The 65 h.p. (DIN) developed by the four-cylinder four-cycle horizontally opposed engine are transmitted via a special reduction gear to the propeller at 1,900 r.p.m. In this manner a high thrust .ffi"i.r"y can be obtained at a propeller diameter which is still practical for light aircraft'

The standard 160 watt/12 volt Bosch generator supplies sufficient current for all illumination requirements and instruments as well as the communications equiPment.

A special feature in this engine class is the electric starter fitted on the standard model which makes the pilot independent and avoids delay at take-off. A choice of two ignition systems is offered, both fully shielded, either dual magneto or dual battery ignition.

Dry sump lubrication assures satisfactory lubrication even during abnormal flight conditions. The oil consumption of 1.5 to 3.5 g/HPh (0.05-0.12 oz/HPh) lies in a very satisfactory range and the SJitre (5.3 U.S. quarts) tank provides an ample salety margin. The high speciflc output of 40 HP/l tr.(2.45 HP/cu. in.) is obtained by the use of a dual down-draft carburettor of high angular stability for use in planes with normal and utility classification, permitting simple stunt patterns such as loops, rolls and steep turns to be flown.

The top speeds obtainable with this new Porsche engine will depend on aircraft type but ranges up to about 200 km/h (135 m.p.h.). Fuel consumption is low, between 2l litres/h (5'6 gaIs.h) at 65 take-off HP and 15.5 litres/h (4.1 gals.h) at 50 HP cruising.

Popular Flying, Iulltl August, 1957

The standard equipment includes wet air-filter, anti-icing and pre-heat system as well as cockpit warm-air supply. Looking forward to stricter noise level regulations the Porsche Company has also equipped this aircraft engine with a highefficiency exhaust muffiing system found on few other engines of this size.

The price for this engine will include all these items as standard equipment of the production rnodel.

In a second version the basic engine is used as described above but fitted with two dual carburettors as well as a cooling blower. This engine has been designed to be installed within

Technical Data

PORS(HE Aircraft Engine Type 67811

TAKE.OFF OPERATION LIMIT:

FUEL:

OIL:

.OIL CONSUMPTION:

DRY WEIGHT:

TorAL wErcHT, including cowling, starter, generator, heating unit, muffier, ignition shielding:

PROPELLER ROTATION:

AIR WORTHINESS RATING:

INTERFERENCE SUPPRESSION:

TEST PROCEDURE:

the fuselage of the aircraft and employs a reduction ration of I .74 : I combined with a somewhat higher power output. The installation dimensions were kept to a minimum in order to provide favourable conditions for pusher screw designs. The take-off power is delivered at 2,600 propeller r.p.m.

Besides these two engines a lighter and simplified power plant, of the same basic type, delivering 50 HP at 3,300 r.p.m. but weighing only 154 1b., also with dual ignition and carburettor pre-heat system although without electric starter, has been developed for very small aircraft. Take-off

5 minutes

80 octane aviation fuel

Shell Rotella SAE 30

1.5-3.5 g/HP/h (0.05-0.12 ozlHP/h)

87 ke (1921b.)

105 kg (2321b.) in flight direction clockwise restricted, categories N and U only; not suitable for snap or inverted mancuvres fully shielded according to British Airworthiness Requirements by Official German Avia- tion Research Centre, Brunswick

Design Characteristics

TYPE:

CYLINDER ARRANGEMENT:

BORE:

STROKE:

PISTON DISPLACEMENT:

COMPRESSION RATIO:

IGNITION:

FIRING ORDER:

FUEL SUPPLY:

CARBURETTOR: AIR FILTER: ELECTRICAL SYSTEM:

MISCELLANEOUS:

4 cylinder, 4-cycle gasoline engme in pairs, horizontally opposed (boxer)

2 spark plugs for each cylinder with dual coil or dual magneto l-4-3-2

I Diaphragm-pump Dual downdraft carburettor wet filter

Bosch generator 160 watt/ 12 volt shielded with voltage regulator Exhaust muffIer; heating system for cabin; carburettor pre-heat system

CORRESPONDENCE

Stubbins Bartlett Aerodrome, Stubbins Bartlett, Nr. Wilking Magna, Cav. 30th June,1957.

DraR Srn, Commander H. C. N. Goodhart raises an interesting point in his letter (this month's popuLAR rrvlNc). The accepted methods of charging flying time need revision and I thought that readers might like to hear how we charge.

My group, the Stubbins Bartlett Co-ownership Private Pilots, Student Pilots and Amateur Constructors Aviating Group, are operating a system which we have called the 'One-shillingat-a-time-seems-less-than-f.2-in-one-go'. This arrangement has proved very satisfactory and our Niddleton Nurge has to have its meter emptied several times a day.

On the instrument panel there is fltted a shilling slot meter, a contents counter and a red light connected to a small bell. The pilot who hires the machine takes with him as many shillings as he feels he is likely to need and these he places in a convenient pocket readily accessible in flight.

When a coin is inserted, the ignition is automatically turned on and the engine ready to start. One shilling lasts one and three-quarter minutes (our rates are low since we service the Nurge ourselves) and five seconds before the ignition is cut, the red light blinks. In the event of the engine having already stopped due to other circumstances, the bell gives audible warning. To prevent the ignition running out during take-off, a slide is fitted above the slot and part of our pre-flight vital actions is to see that there is another coin in this slide ready to be pushed in. Bent or damaged coins are rejected into a tray at the side.

Our system works very well indeed and one member, Ernie Dilthe, flew from Stubbins Bartlett to Bembridge for only 18s. He explained that he allowed the machine to glide between coins and only used the ignition to regain altitude.

In response to requests from our more impecunious members, we plan to fit a 6d. slot as well which will provide just over threequarters of a minute of ignition.

Charging as we do for ignition only means that there is never any arguing about the odd five minutes and I advise other groups-Pay as you Fly.

Yours faithfully,

CHRISTOPHER DREDGING, Hon. Sec., S.B.C.O.P.P.S.P.A.C.A.G.

POLICY AND THE READER

Several people have said that they feel popuLAR FLvING is getting too technical. Perhaps it is. We are of the opinion that the salvation of British private flying is going to lie in the home-built ultralight aeroplane and consequently that articles such as the flrst-class series 'Amateur Aircraft Constructor's Guide' are absolutely invaluable. We are here to serve you, though, and if you would like to see something different, write and tell us. In particular, if you have any interesting stories, historical incidents, or reports of your activities, please send them in. Photographs are always most welcome. The history of the light and ultra-light aviation movement has never been well-documented; with your help we can write our history as we make it. Tell us what your Group is doing; every other Group wants to know. Above all, please do all you can to increase our circulation. Buy as many copies as you possibly can; give your friends a year's subscription for Christmas. Only by. getting a sound, working circulation can we hope to attract the advertising which is our life-blood and without which no magazine, however deserving, can hope to survive.

Popular Flying, JulylAugust, 1957

July 12-13

Jloly 27Aug.5

Aug. 18-25

A:ug.23-25

Sept. 2-8

Sept. 14-15

Sept. 19-22

Aviation Diary

National Air Races, King's CuP and Locheed Aerobatic TroPhY, organised by the RoYal Aero Club.

B.G.A. National Glidine Championships organised by the Surrey Gliding Club. International Parachute Contest, the 'Adriatic Cup,'organised bY the Aeronautical Union of Jugoslavia' International Rally, organised by the Sporting Flying Club.

Society of British Aircraft Constructors -Flying Display and Exhibition.

P.F.A. Rally.

Innsbruck and Salzburg International Air Rally, organised by the Austrian Aero Club.

Baginton

Lasham

Tivat-Boka Kotorska

Copenhagen

Farnborough Sywell

Innsbruck

Don't forget to visit our stqnds Nos. 143-145 at the Handicrafts Exhibition

SMALL ADVERTISEMENTS

Members of the. Popular Flying Associatiort may have the use of this column for advertising articles wanted, exchange or disposal for ONE INSERTION up to 24 words FREE. If more than one insertion it must be paid cash in advance at the rate o.f 4d. per wotd \min. 12 words). Box No. ts, 6d. exfia. Non-members chargeable at the rate of 6d. per word (min. 12 words). Box No. ls, 6d. extra. Cheques and Postal Orders should be crossed and sent to Fryers Advertising Service,lO Mitcham Lane, S.W.16.

WANTED

Main undercarriage Laggs, together with pivot pins and bushes for Aeronca 100. T. A. Sanders, Nandi Airport, Fiji Islands. Light aircraft preferably Whitney Straight but other cabin machine such as Plus 'D' or Auster J.2 or J.4 considered. Must be in good condition and price reasonable. R. Mayes, 4 Gannon Road, Worthing' Tel.: Mincing Lane 3166.

Airman requires cheap, pre-war ultra-light. Condition renovatable. Contact 3524424 ACI Spencer, Rectification' Hangar 3, R.A.F. Feltwell, Norfolk.

Metal Fairey X4 propellor of 3.44 pitch for Walter Mikron Tipsy. Barton Flying Group, Barton Airport, Manchester' Light or Ultra light aircraft, also dual-control training glider for newly formed flying group' Replies to E' McAullv, 20, King George Road, Fakenham' Norfolk.

Advertisement Rates for POPUTAR FLYING

Classified Advertisements 6d. per word, minimum 12 words, Box No' l16 extra Cash with order. Cheques and Postal Orders should be crossed and made payable to FRYERS ADVERTISING SERVICE, 10 MITCHAM LANE' S.W.I6

Basol 99 is harmless on fabric, paint & metal and so kind to the hands. A cleaner plane means a faster plane, so write or telephone BASOL LIMITED l2 Bolton Street, London, W.l. Tel: Grosvenor 3752

THE COMPLETE ATRGRAFT

Used by Aircraf t Manuf acturers, Airlines

*.o,. a seaside landlady

we once knew. She omitted to add 'by Bus' However. when we say 'only ten minutes from the sea'we mean it-we frequently go for a quick swim ourselves !

There is no landing fee for the private flyer at

'Only 10 minutesfrom thg SgU . . .!