Mission Point

Mission Point Beach, California

Mission Beach is a lot of fun especially in August. Here you can laze around all day reading and so on, and the whole place is crowded with athletic young people having a good time exercising and socializing. You can see surfers going into the water and chatting on their way in and out. Waxing their boards or showering off at the public showers, chatting about the waves, and the last time they saw or talked to so-and-so, or what did they do last Friday night.

Wednesdays is an especially good day for watching aspiring volleyball players. Get to the beach early and watch them drill with their coach, hitting volleyballs while un-self-consciously wearing their bikini. At around 10 AM the late comers arrive and pretty soon you can watch some pretty lively volleyball games between some very talented and good looking volleyball players. You can see the men can bash the volleyball around too, if thats the kind of game you want to see.

All of them are pretty smart people, probably attending UC San Diego or one of the other colleges. The especially talented athletes probably get some kind of scholarship, and pro volleyball has become a pretty good career for more than a few young people, mostly the men.

The whole thing is a little like the paradise in one of the old James Bond films where good looking young people cavort in the sun, playing athletic games and admiring each others bodies while socializing and just generally living the kind of life that everyone would lead if this were some kind of James Bond utopia, without anyone like Dr Evil to contend with.

But Mission Beach is fun, and definitely a beautiful side of our society, even if gambling, drugs, cable television, adult movies and liquor is a big part of their lives. It works for them, at least for now!

Anyway I have been coming down here occasionally for about 20 years, and when I do it often seems that I will see a formation flight of F-14's taking off from Miramar and heading out over the ocean. Presumably the flight leader is taking the other crew out to practice carrier landings somewhere out at sea, but you never know, and it doesn't take more than a minute for them to get too small to see, and only a few more seconds for them to be beyond the horizon, which is also out of radar range.

But I don't have any radar and I am left here on the beach thinking about the people I used to work with who were military pilots, including several Vietnam veterans, an A6 pilot, an F-4 Marine pilot who was shot down and evaded capture despite the cracked vertebrae caused by his ejection, and another F-4 pilot who was just on the edge of being crazy, but was employed along with the rest of us as computer engineers and flight planning experts.

The guy who was shot down told me the story about it, he ordered his rear seat radar operator to eject, but there is some stigma about ejections, ejection is just not something any real aviator wants to do. So the RIO, or radar intercept officer, was reluctant to bail out first, which would have been safer, and when the pilot finally bailed them both out, the RIO was somehow killed. This is not that unusual, as it is generally fatal to eject from a 400 or 500 mile per hour or faster airplane, or to eject at higher than about 15,000 feet unless you have bottled oxygen and an electrically heated suit. Francis Gary Powers did not have anything like that, and supposedly above 25,000 feet you are going to black out for a while, just from rapid acceleration. You have to hope you come to before it is time to pull the ripcord. But whatever you do when ejecting the explosive ejection is going to break your back in at least one place, destroy a multi million dollar airplane, and is very likely to kill your RIO if it doesn't kill you both.

But my friend at worked bailed out, and evaded, and his crew man died. He looked me right in the eye when he told me this story, so there is no bullshit here - if they would have stayed they would have died, and it is not like there is any doubt as to whether ejection was the right thing to do.

Anyway the almost crazy F-4 Air Force pilot used to walk around the office talking about different aircraft, and fast cars or fast computers and stuff like that, and he always commented about whether something was a hummer or not. I took it that a hummer was an especially fast plane or car, or girl, and being a hummer seemed to me to mean that the sound barrier was involved. I wondered if maybe things hummed when you broke the sound barrier, or if they put some kind of oscillating device in the F-4 to make it hum, thinking that would make it easier for it to get past the sound barrier.

Years later I met a guy who flew test flights on the first F-4s for the Air Force, and he told me that he took his plane up to Mach 2.26, and as high as 70,000 feet, where it gets dark, and you can see electrical sprites. Well 2.26 is almost as fast as the Concorde can go, a plane that is a much different design than the F-4. Concorde's supersonic design is to F-4s, what the F-4 is to the Cessna, and what the Cessna is to Orville and WIlburs motorized glider. Its just a different design and the idea that a plane that was designed to be faster than Mach 1 could actually go over twice that fast is pretty amazing.

So it made me wonder a bit about what it meant to go Mach 1, and whether the plane actually started humming, and whether it might help reduce "sound friction" if the plane itself could be made to hum. An extension of that is the idea that maybe making the plane electrically charged might help repel air molecules - or something - and reduce drag in that way.

But I didn't know much about it, and then finally after many years I was semi-retired and reading in the library all the things I wished I had time to read when I was 20. It turned out there were some old ideas about slats and spoilers and suction and so on that related to delaying the separation of the boundary layer over the wing. Suction involved a vacuum pump that drew off the air from the top of the wing, sometimes using it as high pressure intake air for the turbines. There seemed to be a lot of confused ideas about it, except that about that time I was on a L-1011 that had holes in the slats, and holes was one way that the old-timers had tried to use to create suction and relieve the boundary layer.

When I worked with the Vietnam veterans I was so confused that I didn't have any questions, and now I was pretty clear on what it was that I did not know. I guess I had always had the questions, I just didn't know what they were yet, to quote one of my old engineering complex math professors.

What is really going on in the boundary layer that makes it such a good thing?
Would it help get past Mach 1 if you were vibrating?
What kinds of things are useful in delaying boundary layer separation?
What is happening after boundary layer separation and can I minimize it?
What is happening to the boundary layer above Mach 1?

It was not an obvious thing, the fact that at Mach 1 you no longer have any boundary layer. You are not born knowing this. There are some excellent diagrams in a paper by von Karman that show the Mach effect as a perspective of pilot's speed. These diagrams let you picture that flying close to Mach 1 is like flying into a tunnel of incompressible air.

Faster than Mach 1 you are past the air before it has time to compress or expand. There are no aerodynamic forces acting on the aircraft. In fact the aircraft is flying through a fluid that is no longer compressible, as if it were water. There are photographs of aircraft flying into a wall of water, or trailing a wall of water behind them. This is best explained by saying that the plane is moving too fast for the air molecules to move out of the way. They can't move, the only thing they can do is pass a sound, a sonic boom, like clapping your hand onto the water at the pool. When the aircraft moves through the air this fast the air molecules suddenly behave as though they were incompressible, and there are air temperature changes involved with becoming incompressible. If there is water vapor present it will all come out, squeezed out, creating the wall of water effect - the contrail.

Picture the air as a wet chain link fence composed of oxygen and nitrogen. A backstop at the ballpark is a good example. The first time the catcher runs back to field a foul ball he jumps up on the fence and all the water shakes off of it. The next time he runs back there the water is gone, he jumps up on the fence and no water comes off. It is the same with incompressible Mach 1 air. The first plane knocks the water out of the air, when the second plane flies through there is no water left.

There are three things that can happen to the water vapor after the first plane flies into it. It can create a fog that is suspended water molecules, it can create a rain or mist that falls down toward the ground, or it can re-evaporate.

As an aside, and as something to think about, let me point out Langmuir's conjecture that water never condenses unless it condenses on something solid. And when water does condense, it gives up its excess of energy in the form of both heat and kinetic energy, adding both heat and movement to the solid thing it condensed on. If anyone has any thoughts - like about how Mach 1 makes the air seem solid to the water molecule, or how condensation can lead to tornadoes, I would like to hear them.