Northern Times (Carnarvon, WA : 1905 - 1952), Thursday 7 August 1930, page 5


Aviation Notes.

A splendid technical success was

announced at the aerial pageant held i

in Rome in June, for the Diesel type

aero engine. On the morning of the j pageant a Fiat aeroplane fitted with ¡ a Deisel engine left the Fiat flying1 . ground in Corso Francia. Turin.- the . start being witnessed by several of

: the firm's directors and engineers, j

This was the first. Italian aeroplane propelled by a crude oil engine, this kind of engine having been first studied and experimented with in Italy by the Fiat Co.

The aeroplane arrived in Rome at the I/ittorio airport at 2.42 p.m. The pilot was Renato Donati, who is well known as the holder of several world's records. He was accompanied by the mechanic Cappannini. This excep tional machine, with its erude oil en gine, then flew over the Littorio field during the air pageant.

This marks a great step forward iu the application of the crude oil eu gine.

Both the daily and the technical press had already announced that the Fiat, was conducting very successful experiments in this field, and the news of this successful flight naturally captured at once the interest of the experts who rightly see in the use bf crude oil a great practical advance in aerial navigation.

As is well known, crude oil has three great advantages over petrol: It is non-explosive, non-inflammable, and costs about five times less than petrol, and therefore permits of the construction of engines of ' greater thermal efficiency, that is, - with a lower spécule fuel consumption.

Consequently, for aviation, the crude oil engine offers these advantages over the petrol engine:

(1.) Greater constructional sim-

plicity ; there are no carburetters or ignition apparatus (magnetos and sparking plugs), the pumps and in-jectors that take their place being simpler and more positive in action.

(2.) Improved thermal efficiency, and therefore a lower fuel consump-tion per h.p. hour and consequently a greater radius of action.

(3.) The use of a cheaper fuel. (4.) No risk of fire.

These advantages are sufficient to make the crude oil engine especially suited for commercial air lines and there can be no doubt that the future of transoceanic aerial communication is bound up with the development of this type of engine, the advent of which In Italy undoubtedly marks a memorable date in the history of Italian aviation.

In order to have an engine of this type available in the shortest possible time for trials, not only on the bench, but also in actual flight, the Fiat, in-stead of building a single cylinder experimental engine, preferred to take an existing aero engine of known characteristics, and convert it into a direct injection Diesel engine. An "A.12 bis" engine was choseu for this experiment. *

Constructional Features.

The "A.N.1" engine is identical in general outline and overall dimensions with the "A.12 bis" type from which it is derived by means of the altera-tions above mentioned.

It has six cylinders in line with a bore of 140 mm. and a stroke of 180

mm. It is water cooled and the only auxiliaries necessary to its working

are the fuel pumps, lubricating pumps and water circulating pump. There are no carburetters, which are re-placed by the aforementioned fuel pumps; neither are there any mag-netos, the ignition of the explosive mixture taking place automatically through the high temperature of the

compressed air. at the moment of in- :

jection of the fuel into the cylinder.

The crankcase, oil sump, crankshaft,

lubricating and cooling systems and

their fittings do not differ from those

ordinarily employed in the usual j types of aero engines. The outstand-

ing features of the new type of engine

are; the cylinders, pistons, valve gear,

fuel pump and fuel atomizer.

Cylinders.-These are of the usual steel sleeve type, with valve chambers and water jacket welded on. They are proportioned to the higher pres-sures they have to withstand, and in their heads have seats for two inlet and two outlet valves, whilst in the centre is the seating for the fuel atomizer.

Pistons.-Of aluminium and of specially designed shape to form a good combustion space.

Valve Gear.-The inlet and exhaust valves are actuated directly off two parallel camshafts, according to the system used in the latest types of aero engines. The inlet valves com-municate directly with the atmosphere and draw in air only, and not an ex-plosive mixture as is the case with petrol engines.

The fuel is injected into the cylin-

ders through the atomizer just when

the piston has nearly finished its

upward stroke, compressing the air previously drawn in. The atomizer

opens automatically through the pres-

sure of the fuel which it injects into the cylinder in a very finely divided state, so as to facilitate its rapid ignition and complete and efficient

combustion.

Fuel Pumps.-There are six fuel

pumps operated by cams and divided into two groups of three. They are

instruments of great precision, as they have to send into each cylinder

the minute quality of fuel required according to the load on the engine, and under extremely high pressure, as

much as 200 or 300 atmospheres. Provision is made for regulating the quantity of fuel delivered by the pumps and also the length of the in-jection period; there is also an ar-rangement for varying the timing of .

the injection.

Control of the engine in flight is therefore obtained solely through the

fuel pumps.

Starting.-The engine is started by compressed air, through automatic

valves on the cylinders and a distri-

butor in the same way as with petro engines.

Actual Working Data.

Results of Tests.-In the length

bench tests to which it was subjected, the engine gave the following results:

Normal output, 180 h.p. Normal speed, 1600 revs. per min. Maximum output, 220 h.p. Maximum speed, 1700 revs. per min.

At the maximum power output, the mean effective pressure (M.E.P.) is 100 lbs. per square inch, remarkably high even for the usual slow running type of Diesel engine.

This engine works with crude oil such as is normally used for four stroke Diesel engines, density 0.86. The consumption of fuel under normal load is about .42 lbs. per h.p. hour, and remains practically constant at

both higher and lower loads. I

The aeroplane had to wait for many years for the petrol motor, but the pioneers of a quarter of a century and more ago were probing the se-crets of the air in gliders.

Now. with the knowledge gained in the air with power-driven aero-planes, men are again turning their attention to gliders, and all over Britain gliding clubs are being form-ed. Gliding, in fact, is likely to be a very popular summer pastime.

Wonderful flights of several hours' duration have been made in these engineless aeroplanes by taking ad-vantage of favorable wind currents

over hilly country, and now an offer

of £1000 has been made to the pilot of the first all-British glider to cross

The English Channel. To accomplish such a flight it vill probably be necessary to attain a great height on favorable air currents over land, and then turn seawards, taking advantage of the steady breeze to maintain height or prevent a too rapid descent.

lt is quite possible that, when we have become more familiar with air conditions, glider flights between de-fite places will be the rule. Mean-while in America a flying-man has towed a glider behind his aeroplane across the continent, making the journey according to a previously ar-ranged schedule in eight days.

Shall we have in future aerial tugs with strings of barges in tow winging their way from continent to continent with the world's com-merce?