Colonel John Stapp died in 1999 at the age of 89. An amazingly old age given what he put his body through in those 89 years.
John Stapp joined the USAF and studied the biophysical effects of flight. Not just the cruising back and forth stuff, the violent accelerations, decelerations, wind blast, loss of oxygen, wind blast, the whole gamut of things that happen in emergencies. And Stapp didn’t just study these things in books, he experienced them; he made himself the test subject.
One of his most famous experiments was the 1947 rocket sled used to test the effects of deceleration on the human body. At the time, it was believed that the human body couldn’t withstand more that 18g. At that point it was believed the internal organs (important things, like the brain) would be pulled apart. It is probably why the X-1 was designed to withstand 18g – no point in the aircraft surviving if the man doesn’t.
Stapp, however, believed that the aircraft crash data he analyzed suggested in many cases that the pilot had survived the initial impact only to be killed by the trauma produced as their bodies broke free of the 18g rated seats and restraint systems.
The rocket sled (nick named “Gee Whiz”) was built by Northrop in Hawthorne, California and consisted of a 1,500lb sled, a 2,000ft long heavy-duty railroad track and several rocket motors.
The deceleration was achieved by “brake buckets” that scooped up water; a similar effect to the end of a theme park ride, but taken to the extreme. At the time it was considered the most powerful hydraulic breaking system in the world – and it probably still is.
Over a four-year period the sled was used to test the effects of deceleration on 74 occasions. Stapp was the rider in many of those cases, sometimes forward facing, sometimes rearward. He suffered everything from bruising to broken bones, but kept getting back on the sled.
One of the first conclusions drawn from the early experiments was that the rearward facing position gave a much greater chance of survival in the event of a crash. Many USAF and RAF transport aircraft were changed to have rearward facing seats as a result of this.
In contrast, civil airlines never took up the idea. I guess they thought their passengers would not like to travel facing backwards. I’ve travelled backwards in a few aircraft and a lot of trains, and can’t say I ever noticed the difference. I don’t know what you think, but to me it’s particularly irrelevant in an aircraft where there is nothing but clouds to look at anyway. But I guess it’s not worth upsetting a potential customer over a silly issue like surviving in the case of an accident.
Stapp also found that the 18g limit used to design the pilot’s seat was inadequate, and the USAF almost doubled its standard to 32g. Stapp also found it wasn’t just the number of g’s, it was the rate of onset that was important. So the restraint systems were designed to have a degree of compliance.
Stapp’s last ride in the Gee Whiz subjected him to an astonishing 45g. That means the forces acting on him were forty-five times the strength of gravity. The force was so great that most of the capillary vessels in his eyeballs burst, turning his eyes almost black.
Jack Northrop witnessed the test and was one of the first to arrive at the sled after the test. He hadn’t wanted Stapp to do the test, and when he saw John’s eyes he was convinced he was blind.
Stapp was blind after the test, but by the next day he had regained almost all his sight as described in this History Channel video. Despite his injuries, he didn’t believe his experiments had found the limit of human endurance, but he had found enough, and his work and bravery has saved a great many lives since. And not just in aircraft.
Stapp went on to use his knowledge and experience to further the cause of placing seatbelts in cars. His sled rides earned him the title “fastest man on earth,” and numerous interviews where he always brought the subject up. The USAF was initially unhappy until he pointed out that more airmen died in car, rather than aircraft, accidents. His efforts were rewarded in 1966, when he watched President Johnson sign mandatory seatbelts into law (just lapbelts at the time, but it was a start). Since its peak in the late 60s, the chance of death on US roads has fallen almost every year, and is currently less than half of the number when Stapp was campaigning. Much of that improvement is due to seatbelts.
John had a level of dedication that is very rare, and you might think he was a dry and serious guy, but far from it, he was humorous and charismatic. He would joke about what he was going to do when preparing for one of his tests, and would often tease interviewers.
In one case, he referred to the work of Major Edward Murphy, his reliability expert. Stapp’s work in the safety field shouldn’t be forgotten, but it is his comment about his reliability expert that will likely be forever remembered.
We do all of our work in consideration of Murphy’s Law.
Indeed, it’s probably why he lived to be eighty-nine. So I don’t know about you, but it’s some advice from a far braver man than I, that I’m going to take to heart.
(Images courtesy of Wikipedia and the EAFB History Office)