Tuesday, November 18, 2008


This article appeared in the Orange County, California, newspaper called the Orange County Register on August 20, 1999:

LeRoy Davis wrote Computer programs for Saturn and Apollo



Local engineers had good reason to be proud as Apollo 11 roared to the moon on July 16,1969. Many parts of the spacecraft were built in Orange County. The Saturn V rocket’s second stage was assembled in Seal Beach by North American. The third stage was made in Huntington Beach by Douglas Aircraft. Autonetics built electronic parts in Anaheim.

Engineer LeRoy Davis, 76, worked on Lockheed jets in 1953 and later on the Saturn V. He retired last year.

“We had to figure out the least amount of weight the Saturn rocket could be for North American in 1962 without it blowing up. No one in the world had ever calculated those kinds of forces before.

The computer memories were too small to do it. They were smaller than the smallest PCs today. So we had to do it by hand. It would nearly kill us, wondering if our calculations were correct. It was like walking on a very thin tightrope. It seemed like an impossible task. A friend told me a way we could do it by computer. So I created the world’s first finite element method (FEM) computer program before even Nastran, by using matrix algebra on the small elements. It worked.---I was so elated!

I had a similar problem at Douglas with the Apollo fuel tanks. I made another program for that.(CASD)

I didn’t know how big a part I had in it until I saw the Apollo astronauts on the moon in 1969. It was quite a feeling.

Computers are bigger today than anything I could have imagined. Much of it was due to the Moon effort.”
Orange Co. Register /8/20/99

LeRoy Junior Davis (who was known as Junior to his family, but LeRoy at work) was a rocket scientist. He developed and used computer programs to determine the stresses and strains that aircraft, jets and rockets could handle. He was a genius.

It is impossible to think that using a computer that had so little capacity, he was able to create a computer program that would figure out how thick the walls of the fuel tanks had to be to withstand the tremendous blast or a rocket engine. The thrust of each of the Apollo rocket engines that took men to the moon was over 1,000,000 pounds. The walls of the engines had to be thick enough to withstand that terrific blast, but at the same time, the weight of the fuel tanks also had to be kept at a minimum. It really was like walking a tightrope.

Junior developed the computer programs that did just that. The fuel tanks for the Apollo 11 moon shot stood up to the rude blast and they were light enough to allow the rocket to get to the moon.


Before the 1970’s the United States had a big problem. Jet aircraft companies would build expensive jets ($1 milllion+). A jet would be flying along and all of a sudden it would hit a bird. The bird would go through the windshield and kill the pilot in seconds. The jet would crash. This was costing millions of dollars.

Initially to solve this, aerospace companies like Boeing and McDonnell Douglas used a manual procedure. They would take a frozen chicken or turkey and shoot it out of a cannon at a jig with a jet windshield in it. The windshield was at a known angle. If the bird went through the window, a new window was placed in the jig at a different angle.

This was time consuming, expensive and a terrible mess.
Junior was given the task of developing a computer program to simulate these bird strikes and find the angle for the windshield where the bird would not go through. By using the inputs of the bird characteristics and the windshield characteristics, a computer program could determine the angle to place the windshield so that the bird would not go through the window. The computer program could be run to simulate bird strikes with the window at an infinite number of angles. Each run of the computer program could represent a different angle. Thousands of runs could be made in minutes.

Junior was successful in developing the computer program to do this for the F111. His computer program is the basis of all computer programs used today by aerospace companies to solve this problem. The report of this program is on file at the WRIGHT AERODYNAMICS LABORATORY.

The report was not done by Junior and it lists his name only once.

The B-2 stealth bomber combines revolutionary aerospace technologies for the world's most advanced aircraft. With its unique flying wing configuration, it is a highly versatile multi-role bomber, capable of delivering both nuclear and conventional munitions.
The sleek, lethal-looking bomber uses advanced composites, such as resin-impregnated graphite fiber, rather than metal.
To build the B-2 Bomber, Northrop Corporation of Pico Rivera, California, and Boeing Corporation of Seattle,Washington, formed a team under the direction of the United States Air Force. Boeing built the outboard portion of the B-2 stealth bomber wing, the aft center fuselage section, landing gears, fuel system and weapons delivery system. Northrop built the rest. After each one got done with their parts, the parts were to be put together at Northrop. The United States Air Force was over the entire operation.
The B-2 presented a big problem for engineers, especially at Northrop. The skin of the B-2 was to be made out of a new material called composite material. The reason for this was that the B-2 needed to be a stealth bomber, meaning it needed to be undetectable by radar.

Another reason for this was that composite material was lighter than traditional all metal skins and yet it was as strong or stronger.

Since it was new, the traditional methods to determine the stresses and strains on the new material would not work. At first, Northrop did not have the computer programs to do the stress analysis and they were having a difficult time to convince Boeing and especially the United States Air Force that they could do the stress analysis for their part of the B-2.

A test of the ability of a computer program to do the stress analysis was that a mockup would be made of the B-2 and a 10,000 pound weight would be applied to the wing tip. The job of the computer program would be to predict how much the wing tip would deflect at the end with the 10,000 pound weight place on it. The test would then be done on the mockup to see if the program correctly predicted the deflection. The computer program would be considered to be successful if it predicted the deflection by 1 foot or less.

Junior was called in to solve the problem. By modifying his previous programs and using some special tricks that he knew, he came up with the computer programs that passed the test. This convinced the United States Air Force and Boeing that Northrop could do their work. It was because of Junior that many jobs were created at Northrop to build its part of the B-2. Had it not worked, Boeing would have done the job and Northrop would have had a lot fewer workers.

Junior’s computer program predicted the deflection within inches.

WHO’S WHO 2004-2005

In 2004, Junior was notified that he was being honored by the National Register’s Who’s Who of Executives and Professionals. The intent is to notify all that LeRoy Junior Davis has reached the level of recognizable success in their respective fields.


Junior received this plaque from the National Register Who’s Who in Executives and Professionals


Junior had many talents. He was a great teacher, an terrific artist and an avid stream fisherman. During World War II, he went to Japanese language training school to become an interpreter.


Junior graduated from the University of Colorado in 1945 with a Bachelor of Science Degree in Civil Engineering. In 1949 he went back to the University of Colorado and did graduate studies with the goal of getting a Master’s Degree.

During that year, he taught a statics and dynamics class. During the class he would have the students work on their homework and he would have them work their problems on the blackboard. He would show them the techniques and tricks that they needed to work the problems. He did not teach about the philosophy how to do the problems. He showed them how to solve the problems and the techniques needed to solve them.
At the end of the class, he gave them a test. There were quite a few students in the class. They all got “A”s on the test.
Junior was called on the carpet by the dean of the Engineering College. He said it was impossible for all the students to get “A”s on the test. “It must have been an easy test”. Junior said, “OK! You take this test. This is the test I gave them.” The dean tried the test. He had to admit that even he could not have passed that test.

As a young man, Junior took art lessons for a professional artist. Junior was very good. He did the a lot of art work for people. He made a cover for the High School Graduation. He drew a picture of his old home in Clinton, Utah.
Here is some of his artwork:







During World War II, Junior got into a program to learn Japanese. The intent was for him to become a Japanese language interpreter. The war ended before he could use the skills he learned as an interpreter.

The language school was very tough. There were only a handful of people in the class and they were very smart. Junior said that they all had photographic memories except for him. One of them told him, “If I had to study as much as you do, I’d give up and go out to the front”. To stay in the class, you had to get above 90% on the tests every day. If you didn’t , you would be sent to the war front as a sea bee. A Sea Bee was the first one in on a beach front during a battle. You would essentially be cannon fodder.

Junior said that in the morning when he first started, it was like he didn’t know anything that he had learned previously even after he had been studying at the school for a long time. However, by mid morning, it all rushed back and he could write and speak better than anyone in the class. Junior was especially good at writing Japanese characters. That was due to the fact that he was a terrific artist and to draw the Japanese characters, artistic ability really helped.


Junior grew up in Zion and Bryce Canyons because his father, Franklin LeRoy Davis, was an engineer building the roads through Zion and Bryce. In Junior’s family, everyone went by their middle name. Junior’s full name was LeRoy Junior Davis and so he went by Junior his whole life (except at work).

His father, Franklin LeRoy Davis, went by Roy Davis.

Junior was the oldest in the family. The next oldest was James Reid Davis. He went by Reid.

Next was Wayne LaMarr Davis. He went by LaMarr.

Then was David Allen Davis. He went by Allen.

And finally there was Lenora JoAnne Davis. She went by JoAnne.

Roy taught his sons how to fly-fish for trout in the streams in the area of Zion and Bryce. So, Junior and Allen formed one team, and Reid and LaMarr formed another team. The idea was that the team with the most fish and the biggest fish for the day was the winning team.

One day, Reid and Junior were working the same pool of water. Reid hooked a really big rainbow trout and horsed it out of the stream onto the bank. As he did so, the fish flopped off the hook onto the stream bank. Junior let out a whoop and ran after the fish. Reid and Junior wrestled each other to get the fish. As they did so, the fish slipped back into the stream. Reid was furious. It would have been the biggest fish of the day.

Fishing was ingrained into Junior his whole life. Whenever he went on vacations, it was to go fishing. He didn’t care where it was, if it was a stream, he would go fishing on it. He liked to go fishing on a stream in Yosemite called Big Creek. It was a terrible stream because it had lots of overhanging branches to catch the hook on the fly.

But, amazingly, he would usually catch his limit on that stream.

A much better stream was near Bryce Canyon called the East Fork of the Sevier River. It meandered down a meadow and there was not a lot of brush hanging over the stream. The rainbow trout were nice and big and usually plentiful. It was a lot more pleasant to fish.


Junior was a genius at work and very smart. He loved mathematics disciplines of algebra, geometry, trigonometry, and calculus and he knew how to use them in his work. He has helped many a student with math problems, especially geometry. He loved that. He loved helping people learn to do math.

He used matrix algebra and calculus in the programs that were used to determine the thickness of the fuel tanks that sent the Apollo 11 to the moon.

He was the ROCKETMAN.

1 comment:

Baak Talk said...

I've read this before but not on your blog. Junior truly was amazing! I wish he were still here to tutor Bryce. Bryce would have loved it. I really think Bryce was the perfect namesake for our family. He has that kind of mind.

Gives me chills reading the story of this amazing man, my grandpa!