FIRE PERIL IN THE AIR.

Oamaru Mail, Volume XLII, Issue 12823, 15 April 1916, Page 1 (Supplement)

FIRE PERIL IN THE AIR.

(By C C. fi.-y. Editor ..t rhe ■■ Aeroplane.".! The British. Vr.Hirh. ;iac (i'ftiu.u! ••;- | licial communiques frequently enemy aircraft, which have !»?oc hit o, I missiles from the ground or from other aeroplanes us "falling t<> tho earth :i of flames." It must be understood iliat these fires ah* not caused through enemy shells bursting in the aeroplane. Prob•abiy not more than 1 per cent, of the fatalities which accrue to military aviators are due' to direct hits by shells. In almost*every case the damage is done by xifle ballets or shell splinter* hitting -vital' parts of . the machine. They may shatter a wing-spar or a wing-stay, and so cause the aeroplane to collapse; - the engine 'may be disabled and enforce an involuntary landing on bad ground, with the consequent wrecking of the machine; the pilot may be hit himself, or, finally, tho petrol tanks or pipes may be punctured. .* ■ '

STEAM OP FLAME. It is the lost contingency which is responsible for the many fires which occur in mid-air. A powerful aeroplane uses an enormous amount of petrol per hour, and many machines are fitted with tanks capable of holding a quarter of a ton or more of it. In tractor biplanes, which are now s" largely used both by the Allies and tho Germanic Powers, tho petrol tanks are generally in the front of the enclosed • body of the machine. A bullet from a machine gun or riHe fired from the ground pierces the bottom of the tank, and immediately a thin stream of petrol starts to pour down. Most of it is swept away to the rear of the machine by the propeller Wast and the passage of tlie machine through the air, but the curious air eddies which form round the nose of an aeroplane draw' it out in "wisps through cracks and crannies in all directions, and if any of the vapor comes in contact with a spark or an incandescent surface it will catch fire. So inflammable is the petrol vapor that immediately a flatno is produced it will run back to the source of the leakage like wildfire and cause a conflagration which cannot he extinguished. In the pusher type of machine, which havo itbcir engines and propellers at tho rear of the car or nacelle, similar disaster may occur. A particularly sensational incident of this kind occurred recently to a British biplane, hut fortunately the pilot was able to land just in time, and was ultimatoly rowarded for his bravery in saving the life of his passenger. While reconnoitrinn over the enemy lines a stray shell splinter hit the tank and caused the petrol to flow down into tho body work, where it caught fire. The leakage was so rapid that the petrol fell in blazing streams to the floor of the machine and washed round the feet of the pilot and passenger. The heat got so intense that. | tho goggles were cracked 'on the faces of the men, and the ammunition for the machine gun caught fire and exploded 'in all directions. Hardly had tho pilot landed, when .the machine literally fell to pieces.

FATAL SPARKS. TJio cnuse of escaping petrol igniting in this wny is generally sparks ia the magneto, flames from the exhaust, or Incandescent exhaust pipes. Fatal fires have also been *he result of a bullet striking; the magneto or the timing gear, resulting in the creation of a spark in a cylinder at the wrong moment, as, for instance, when the inlet valve is open. Not infrequently aeroplanes burs'into flauies wheii they land heavily owing to damage caused by the enemy or by unskilful piloting. Not Jong ago an inquest was held on the body of a passenger who was burned in an aeroplane smash in England. The pilot had handled the machine clumsily, and !t fell a short distance,' striking the ground with considerable violence. Neither he nor the passenger was seriously injured by the fall, but unfortunately the shock burst the tank, the petroi poured out, and the vapor reached a glowing exhaust pipe or perhaps a spark before the magneto had qinto ceased; to work. At any rate, the name blew hack into the machine, and before the passenger could bo helped out he was so badly burnt that he died soon afterwards. Much thought lias been given" to the prevention of these tragedies, but petrol is so volatile that it is impossible to isolate it from contact with the engine. The only cure seems bo be to do witliout petrol. With this view in mind much money has been spent on inventions to utilise paraffin (or kerosene) in aeroplane motors.

THE REafEDY. The safetv of lies in its high flash point." It will riot evaporate in inflammable proportions at the ordinary temperature of the air, and it has to be heated artificially in order to turn it into gas. The only source of inflammable vapor is through the carburetter, and this vapor condenses so rcadilv that it liquefies almost as soon as it enters tho air. so that the chances of escaping vapor jumping to the magneto or the exhaust pipes are very small indeed. . In the event of a parafim-dnven aoroplano smashing on the ground, thero is some small risk of any fuel winch escapes from the tank catching fire as it falls, but in this case it will lie seen that the first outbreak will onlv bo local. Tho flames cannot jump back to the tank along » patch of vapor. They must burn so fiercely that the actual heat sets the main supply on fire, and in the meantime the crew have a chance of escaping. Tho paraffin carburetter has always been looked on with longing, by motorengineers, Ijecanse an engine run on this fuel nnder efficient conditions can be made to give more power titan when run with petrol, owing to the greater calorific energy which paralhn possesses. A professor in a British universitv has just devied a means ot fettui" over tho main difficulty, an'J is invention has lieen running a car engine for some weeks with perfect efficiency. The horse-power developed lias surpassed the expectations of theorists to an astonishing degree, -and it looks verv in itch as if its final adoption on aerni'taiics will Jesuit in the elimination or one of the greatest dangers the aviator has now to face.