FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1955
1955 - 1717.PDF
836 FLIGHT Supersonic Bale-out The First Two Successful Escapes at Over Mach 1 TWO pilots have this year successfullyescaped from aircraft travelling atspeeds in excess of Mach 1. One was American and the other British and, thoughboth received injuries, each has largely recovered from his experience. In each case the aircraft went into a dive inwhich the speed built up and the controls malfunctioned in a way which made it impossible to pull out. One aircraft was aNorth American F-100A, on a manufacturer's test flight, and the other was a Hunter in squadron service. There is no reason tobelieve that the loss of control was caused by any basic default of either aircraft. The pilot of the Hunter (as recorded in Flight of Novemberlith) was F/O. H. Molland. Though no detailed official report has been made public, it is thought that he baled out at 25,000 ftat an indicated Mach number of between 1.1 and 1.01, i.e., at a true air speed of between 710 m.pJi. and 765 m.pJi., and in asteep dive. The exact sequence of escape actions is not known, but during the escape he was subjected to a very high windforce. This was sufficient to strip him of gloves, helmet and oxygen mask, and to carry his arm back behind him, breaking it on theseat. Blast on his face gave him two black eyes. When he reached hospital his pelvis was also found to be broken. The automaticseat mechanism worked perfectly, however, and at the correct height, about 10,000 ft, his parachute opened and he descendednormally. He landed in the sea off Felixstowe and was luckily picked up almost immediately by a range-safety launch. TheMartin-Baker seat therefore appears to have performed its full duty in decelerating him and taking him rapidly in a stabilizeddescent down to the parachute opening altitude, where it pulled the rip-cord for him. But it could not protect his body entirelyfrom the violence of the airstream. The events of the American escape are somewhat different,partly because of the design of the American ejector seat, partly because of the very, much less favourable circumstances of theescape and partly perhaps because the pilot had not time to perform the actions necessary to give him the best chance ofescaping damage. In fact, at such a speed, the chances of getting completely away with it were remote in the extreme, as severalprevious unsuccessful attempts had already shown. The man was George F. Smith, aged 31, production test pilotfor North American at Los Angeles International Airport. Asked unexpectedly to test a new production F-100A, he took off wear-ing his flying overall over a sports shirt, nylon jacket and denim trousers. The weather had just cleared and he made a routineclimb through cloud with the afterburner on and at a speed close to Mach 1. Seven minutes later he was at 37,000 ft and levelledoff still with the reheat on. It was when he could not trim out the normal slight nose-heaviness as the speed built up that herealized that something was amiss. Thereafter the aircraft went into a steepening dive and the control column refused to move. While Smith wrestled with the controls the speed built up toover 800 m.p.h. and he called on the radio that he was in trouble. Another North American test pilot in the area then saw him flypast at high speed and told him to bale out. Smith knew from past reports that it was considered fatal to attempt a bale-outat such a speed, but decided to try it as a last resort, rather than dive into the sea with the aircraft He pulled down the visor of his crash helmet and thenthrottled fully back and extended the speed brake. The Machmeter still showed supersonic speed and the rate of descent was1,140 ft/sec. Without pulling his legs back onto the stirrups or otherwise taking up the ejection position he pulled the hood-jettison control and was immediately almost overwhelmed by a noise which he termed as the loudest continuous sound he hadever heard—something akin to a continuous explosion. This considerably unnerved him and he ducked forward to escape it,thus putting himself in a poor position for ejection. His head was almost on his knees, and with his feet still on the rudderpedals and left hand on the throttle he operated the ejection trigger in the right hand armrest of the seat. The cockpit configuration of the F-100A, from which one of the supersonic escapes described below was made, can be seen in this view at Los Angeles International Airport. The aircraft shown came off the production line tour places ahead of the one concerned in the account. The American ejector seat has no face blind and the firing andhood-jettison controls are in the collapsible arm-rests. The moment at which he is thought to have squeezed the trigger (andhe has no recollection of actually doing this) was his last conscious moment for five days. Some men in a motor boat on the sea below the F-100A werereturning to port when their craft was shaken by a terrific ex- plosion which nearly capsized it. Those on deck looked roundto see a fountain of water spurt up a few hundred yards astern and understandably assumed it to be a mine or shell exploding.Then they saw, and examined through a telescope, an inert body falling with a torn parachute. Less than a minute after Smithstruck the water the boat was alongside and he was pulled aboard. His shoes, socks, helmet, mask, gloves, watch and ring had alldisappeared. His clothes were in ribbons and his face severely lacerated. His stomach had been so filled with slipstream airforced down his throat that—luckily—his body floated without inflated Mae West until his rescuers reached him. Severelyshocked and delirious, he spoke only a few incoherent words on the way to hospital. • After the wreckage had been salvaged by divers, and witnessesinterrogated, it was calculated that Smith had baled out at about Mach 1.05 at 6,500ft—an air speed of 777 m.p.h. He was sub-jected to a deceleration of 40g by the airstream, broadly equivalent to a body weight of 8,000 lb. Air pressure on him was 1,240lb/sq ft. In the American seat there is no stabilizing drogue system to prevent toppling of the seat and to decelerate it before the har-ness is released automatically after two seconds free fall. After that a barostat in the pack releases the parachute as soon as the pilotdescends below some 10,000ft. Smith therefore tumbled over and over and slowed down several hundred miles per hour in a fractionof a second. The clinical details do not make pleasant reading, but they must be given for the record. Smith's eyeballs werethrown forward against the lids and his internal organs were severely jarred. The end of his nose was torn off by the mask andhis face was bruised and cut. The great blast of air on his stomach forced blood into his face, distending it beyond recog-nition, and the air forced down his throat had later to be removed by stomach pump. As the seat tumbled he was battered fromall sides, and when he was released from it his parachute opened after two seconds and one-third of the fabric was torn away.His legs had been severely strained by flailing violently in the airstream, and his body was badly bruised by being batteredagainst the seat in all directions. In hospital it was found that Smith's small intestine was per-forated and his liver badly damaged. He had no fewer than 20 subconjunctival haemorrhages in the eyes and it was thought forsome time that he would not see again. But finally, after seven months and several operations, he has recovered sufficientlyto qualify for a private flying permit, and has regained perfect vision. His eyes are, however, sensitive to glare and adapta-tion to darkness is slow. His liver is damaged to the extent that he can never take any alcohol again and his right knee occasion-ally gives trouble—a result of the flailing of his legs in the air- stream after ejection. Before the accident Smith weighed 215 lb,but this figure dropped to 150 lb while he was in hospital. Now his weight is back to 175 lb. The punishment that Smith received after ejection has beenapproached only by subjects on the U.S.AJF.'s rocket sled, and he is thought to have reached the very limits of human endurance.The case has been closely studied by many aero-medical experts, and the problem of protection during bale-out at such high speedshas been brought into sharp relief, especially since aircraft of such performance are now in large-scale squadron service with theU.S.A.F. The solution for such extreme cases as that of Smith is being sought in two types of jettisonable capsule cockpit nowbeing actively developed for American aircraft.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
