Four Bit Carry Adder/Subtractor Circuit

After creating my 1 bit full adder design found in a previous post, I decided to go for something a little more complicated. I wanted to prove to myself that the ripple carry system worked, so the obvious choice is to make a multi bit device. 4 bits seemed like a good amount, it’s a value used in some early ALU’s so it can be used in a future project. To make it more interesting I added in the ability to make the device a Subtractor at the same time. When you look at the schematic, it only requires one more device per adder, so it’s not even an expensive thing to implement, but adds lots of functionality. As with the 1 bit adder, I have attempted to build this adder using only single logic chips.

4 bit adder-subtractor circuit

The first stage is to know the logic circuit, its widely known and can be found pretty easily all over the web. I’m not going to explain how it’s created (I can always make a separate post on that) but I can describe how to use it. The aim is for the device to take two 4 bit inputs (0 – 15), along with a carry from another adder. So the adder needs to be able to output a value between 0 and 31. In binary this can be shown as 5 bits, so we have 2 outputs. This the S output is a 4 bit bus, and the Co output bumps this up to the 5 bits we need to make 31. A truth table can be made for this but it would be 32 lines long, so too much for this post. You could regard it as a personal challenge if you want to attempt it on your own.

So I got onto Altium and made a schematic of this circuit using some of the low voltage 7400 LVC series individual logic gates that I used on the previous adder I made. They come in SOT23-5 packages which are leaded a nice size to solder. Plus they are a size where it’s possible to probe the pins fairly easily. Luckily Altium shows the components as their logic symbols. Below I have shown the first two adders, the third and fourth are basically the same as the second one, which is the idea of the ripple carry adder.

The first two adders of the four found on the board

I also added a few LEDs to show what parts are on and off. This means the user can see the inputs and outputs. These LEDs run off the 5V input voltage, and have 220Ω current limiting resistors in series with them. Also, I have put in some 0.1 inch header pins so it can be attached into a breadboard and maybe even a micro.

The LEDs for the carry bits and outputs
The LEDs for the input bits

As a base of my circuit, I have decided on a double sided 100mm x 100mm board. This is quite big as you can see for the circuit I have made, but gives plenty of space for a soldering iron to get access. As well as this, it gives a nice amount of space for multimeter probes. I also tried to keep the individual logic chips in a similar arrangement as the schematic. This is meant to be used as a learning device, so it’s useful for the chips to line up with the diagram. The header pins for the inputs and outputs are placed on opposite sides of the board to make it more obvious for the user to see it. And the pins have designators written on the board so the user can see what each pin does. The input and output busses are placed in fairly logical places, and grouped together. There is no point having all the A inputs intertwined with the B inputs. The pins for the power and ground are on opposite sides with their own headers, only one needs to be connected for it to work. The LEDs that are directly attached to the pins are placed closer to the logic circuitry, but labeled clearly on the silkscreen. Most of the routing to the LEDs is on the underside of the board, else the top could get confusing. All the designators for components have been made half the normal size due to the small amount of parts used in the project. The below images show the PCB layout I created with the top copper being red, bottom copper being blue, and the silkscreen shown in yellow.

Top Copper

As you might be able to see, I have tried to keep all the power on the bottom side of the board. This leaves lots of space for the logic signals on the top, where the user is more likely to see. As you can see, most of the inputs and outputs of the circuit are also on the bottom side. This is because the way the busses work and input into the adder needs lots of crossing over and would add confusion into the design. This is why labels were used instead.

Bottom Copper

To make it easier to see, I made a larger image of the first and last adder in the series. As you can see, the only real difference in them is that the first has the add/subtract input shown by an LED, whereas the last shows the carry from the previous adder (C0). This is because the A/D bit is attached to all the adders, but the first bit doesn’t have a carry bit input. The carry on that adder is the input for the A/S. It serves the function of inverting the first bit, so that it works like 2’s complement when in subtract mode.

The layout of the first adder in the series
The layout of the last adder in the series

As noted above I used 7400 LVC series logic gates. The SOT23-5 package chips have the suffix of “BVD”. See the datasheets for each of the devices for more information. I have written a simple bill of materials below:

12x SN74LVC1G86DBVT – XOR gate
8x SN74LVC1G08DBVT – AND gate
4x SN74LVC1G32DBVT – OR gate
17x DO-214 LED’s
17x 0805 220Ω resistors
6x 5-pin 0.1″ header pins

The main downside to this type of adder is that is is very slow. Especially when you get to high bit amounts that you are trying to add. This adder will take at least 4 times as long as a single adder to add the two numbers together because the signal has to propage through 4 full adders. This problem is known as propagation delay, each logic chip will take a very short time to compute the output. Although this time is not perceivable by the human eye, if there are 100’s of logic gates in a row, then the delays start to add up and be a problem. If this circuit is to be used in a computer, it could need to make calculations thousands, or maybe millions of times a second, and a carry bit adder is not generally good at that. There are other, faster adders that I will show in a future post.

Why James Webb Was so Important

NASA Administrator James E. Webb
NASA Administrator James E. Webb. This was his official NASA photograph

There are not many people who know off the top of their head who James Webb is, even many lovers of space may not know who he was. Yet they are about to launch the James Webb Space Telescope into space to replace Hubble. James Webb wasn’t an engineer, or a physicist, or even really an academic; he was a lawyer and politician. He turned a small government research department into an organisation that had links to almost every state, and had control of 5% of the US federal budget. Webb’s NASA controlled the jobs of half a million workers across America, and he introduced new working practices and management techniques that are still used today.

If you were to go out and read the biographies of the astronauts, or histories of spaceflight, Webb doesn’t really come up. He was portrayed as just a bureaucrat in Washington, funnelling orders down the chain, living the politician life. In this new age of spaceflight, we see the Apollo years as some sort of poetic story, with NASA being the figurehead of the battle to win space against the evil russians. In 1961 though, America did not follow this narrative, nobody in America cared about space, least of all the brand new president, John F Kennedy. When he set up his first reshuffle of the cabinet they simply could not get anyone to run NASA, they asked 18 high level politicians, and everybody said no, space was a dead end job, and NASA was just a collection of squabbling mission centres. Eventually, JFK’s vice president, Lyndon B. Johnson suggested Jim Webb, a guy who had worked under the Roosevelt administration and had some experience with private businesses. When asked, by JFK personally, Webb agreed to run NASA, as long it was the way he wanted it. JFK, desperate for an administrator gladly agreed.

shaking hands with JFK
President Kennedy shakes hands with NASA Administrator James Webb

There had been heavy opposition to the idea of manned spaceflight. Up to this point, the head of the President’s Science Advisory Committee, Jerome Wiesner, had issued a critical report on project mercury. Kennedy, as a senator he had openly opposed the space program and wanted to terminate it. Kennedy put his vice president LBJ as the head of the National Aeronautics and Space Council because he had helped create NASA, but it was mainly to get him out of the way. Although Kennedy did try and reach out for international cooperation in space in his state of the union address in January 1961, he got nothing from Khrushchev. Kennedy was poised to dismantle the effort for space, purely because of the massive expense.

The space Council
Vice President Lyndon B. Johnson (seated, center) presides over a meeting of the National Aeronautics and Space Council.

He began his NASA administration on February 14th 1961. A month later on April 12th, Yuri Gagarin became the first man to orbit the earth. Reinforcing some fears that America was being left behind in a technological competition with the Soviet Union, America suddenly cared about space. Kennedy made a U-turn and space sped to the top of the list.  This lead to Kennedy making his famous speech on May 21st where he spoke those famous words “we will put a man on the moon before the decade is out”. Kennedy wanted to take lead in the space race. Suddenly, putting a man on the moon was the number one priority.

Kennedy Talking to Congress
MAy 1961, Kennedy proposes landing a man on the moon to congress. LBJ and Sam Rayburn sit behind him.

This meant that James Webb just got handed the opportunity to run the biggest single project the country had ever seen. Webb was told to go back to his engineers and figure out how much it will cost to get to the moon. His engineers came up with the number of $10 billion (a scary big number in the 1960’s), and sheepishly told Webb, expecting to be told to make cuts and slashes to the plan. Instead he told them to go higher, because he knew problems would come their way, and extra money will need to be spent, so they come back with the figure of $13 billion. Webb accepts the number, and goes to congress and tells them he needs $20 billion over the next 7 years. Jaws hit the floor, but he used this political knowledge to get a huge amount of leverage.

The key leverage he had was jobs, and he knew it. At its height, NASA employed half a million people in some form, that’s roughly the number of people living in Wyoming. The two biggest investments were in Cape Canaveral, FL and Houston, TX. The most controversial was the Manned Spaceflight Centre in Houston, donated by Rice University. Originally based in Langley Virginia, and named the Space Task Group, the senator didn’t care much for space. The entire operation was moved to Houston, LBJ’s home state. It was central, and had good universities surrounding it. There were many Texas based representatives in the space political landscapes at that time, such as Sam Rayburn, the speaker of the House of Representatives.

Johnson Space Centre
Manned Spaceflight Centre, Texas, one of the biggest employers in Texas for a long time. with over 3000 federal workers, and 100 buildings

One thing that Webb understood was what NASA needed to run. He implemented a very flat organisational structure, with very few middle managers. Webb was the very top, controlling Washington. He also had the head of NACA (precursor to NASA) Hugh L. Dryden as an associate director. He had overseen the development of the x-15, and understood the technical needs of Apollo. Also Robert Seamans, also an associate director, acted as the general manager of NASA, and oversaw the everyday running of the program. Using a team of people, each with their own particular strengths helped NASA, especially in the early growth years, much more so than any one of them could achieve on their own.

Webb in a Gemini Trainer
Webb in a Gemini Trainer

Part of what James Webb did, to the dislike of congress, was to invest in academia, specifically universities. $30 million dollars a year was put into the Universities Development Fund. A fund designed to help students get into engineering, and to develop talent, skills, and academics that could not only work for NASA, but help the science behind it. As it was taken from a fund that congress had no control over, the money continued to help 7000-8000 students a year get through university at a time where NASA needed engineers. Webb believed that NASA was more than just the one shot to the moon, and frequently fought with the presidents on that fact. He wanted NASA, and space exploration to benefit science, engineering and even society. He believed that this project could fix other problems not even related to space, such as poverty and disease. The management style of NASA, and the way these big projects were handled showed the impossible could be achieved. He frequently lectured on this subject, and universities became an important part of NASA.

Launch_Complex_34_Tour
Webb, Vice President Lyndon Johnson, Kurt Debus, and President John F. Kennedy receive a briefing on Saturn I launch operations

There was huge pressure from washington to spend all of NASA’s budget purely on the Apollo moonshot. Webb was instrumental in making sure that NASA and spaceflight was more than that. be made sure other projects like the Mariner and Pioneer space programs happened, and that JPL still functioned even with a terrible track record at the time. At the time, the academic community worked with NASA, in large part because of the importance Webb put on furthering science. Webb would frequently lecture at universities, and teach about the management styles that made NASA was. Unfortunately, some in Washington didn’t care for the extra spending, especially the states that did not have a mission centre or any of the major manufacturing plants located there. So when the Apollo 1 fire happened, there were a small group that were willing to use it as a way to make changes.

Closeup of James E. Webb, National Aeronautics and space administration

The Apollo 1 fire was a very unfortunate accident, and a national tragedy. For some, it highlighted some major problems with the Apollo program and how it had been run by the major contractor North American Aviation. Committees were set up, and Webb suddenly went from running NASA to trying to defend it. During the inquests, NASA still ran, it continued to fix problems and aim for the moon. This was because James Webb was there defending it. Left to just take the heat, some believe (me included) NASA’s funding would have been significantly cut, and we may have never got to the moon. Webb stood up in Washington and fought hard for the continuation of the project, defending the decisions that his team had made. At the end of it, he had used up most of his political sway, and called in so many favours that NASA was safe for the time being, and that Apollo was possible.

Webb presents NASA’s Group Achievement Award to Kennedy Space Center Director Kurt H. Debus, while Wernher von Braun (center) looks on

At this point, Johnson had decided not to run for re-election, Webb felt that he should step down to allow Nixon to choose his own administrator. On October 7, 1968 he stepped down from office. To put that into perspective, Apollo 11 landed on the moon July 20th, 1969, barely a year later. Webb went on to be a part of many advisory boards and served as regent for the Smithsonian institute. He died in 1992, and was buried in Arlington National cemetery.

This post was inspired by reading the book: The Man Who Ran The Moon by Piers Bizony. For anyone interested in the subject of how Webb actually made his dealings, and a much more detailed account of how NASA became what it is, I recommend this book. He also did a Lecture on Webb that I found on YouTube where he tells the story really well.

 

One Bit Adder Project

One thing that has always been interesting to me is using logic circuitry in electronics. It’s easy to implement something on a microcontroller in just a few lines of code, but the real challenge comes from making a boolean project using real logic gates. It’s something we all learn about if you have taken a basic computer science class, or even digital electronics. One of the first circuits you ever learn about is the adder. It’s pretty simple, teaches you how to cancel down boolean equations, and only has a few inputs and outputs. I have decided to try and make the circuit using real components, and see if I can get it to work.

full adder layout

The first stage is to know the logic circuit, its widely known and can be found pretty easily all over the web. I’m not going to explain how it’s created (I can always make a separate post on that) but I can describe how to use it. The aim is for the device to take two 1 bit inputs, along with a carry from another adder. So the adder needs to be able to output a value between 0 and 3. In binary this can be shown as 2 bits, so we have 2 outputs. The S output represents bit 1, and the Co output represents bit 2. Below is the truth table I used, if you want a little challenge, try and get the above circuit using boolean algebra.

A B Ci Co S
0 0 0 0 0
0 0 1 0 1
0 1 0 0 1
0 1 1 1 0
1 0 0 0 1
1 0 1 1 0
1 1 0 1 0
1 1 1 1 1

So I got onto Altium and made a schematic of this circuit using some of the low voltage 7400 LVC series individual logic gates. They come in SOT23-5 packages which are leaded and a nice size to solder. Plus they are a size where it’s possible to probe the pins fairly easily. Luckily Altium shows the components as their logic symbols.

1 bit adder 1 schematic

I also added a few LEDs to show what parts are on and off. This means the user can see the inputs and outputs. These LEDs run off the 5V input voltage, and have 220Ω current limiting resistors in series with them. Also, I have put in some 0.1 inch header pins so it can be attached into a breadboard and maybe even a micro.

1 bit adder 1 schematic

As a base of my circuit, I have decided on a double sided 50mm x 50mm board. This is quite big as you can see for the circuit I have made, but gives plenty of space for a soldering iron to get access. As well as this, it gives a nice amount of space for multimeter probes. I also tried to keep the individual logic chips in the same arrangement as the schematic. This is meant to be used as a learning device, so it’s useful for the chips to line up with the diagram. The header pins for the inputs and outputs are placed on opposite sides of the board to make it more obvious for the user to see it. The pins for the power and ground are on the same side on both headers. The LEDs that are directly attached to the pins are kept close to them, and the track is fairly obvious to show where the signal is from. The silkscreen labels which LED designates which input/output. All the designators have been made half the normal size due to the small amount of parts used in the project. The below images show the PCB layout I created with the top copper being red, bottom copper being blue, and the silkscreen shown in yellow.

1 bit adder 1 PCB top

As you might be able to see, I have tried to keep all the power on the bottom side of the board. This leaves lots of space for the logic signals on the top, where the user is more likely to see. As you can see, not all signals are on the top side due to circuit constraints, but signals that do swap over are generally short jump, and straight lines, This makes it more obvious where the tracks go without having to flip the board.

1 bit adder 1 PCB bottom

As noted above I used 7400 LVC series logic gates. The SOT23-5 package chips have the suffix of “BVD”. See the datasheets for each of the devices for more information. I have written a simple bill of materials below:

2x SN74LVC1G86DBVT – XOR gate
2x SN74LVC1G08DBVT – AND gate
1x SN74LVC1G32DBVT – OR gate
5x DO-214 LED’s
5x 0805 220Ω resistors
2x 5-pin 0.1″ header pins

The Foundry: Drilling an Air Hole

At this point we had a cast foundry base, made out of sand and plaster of paris. To see how that was made, see the tutorial here.  Before we first test it though, we had to make one modification, and that was to drill a 30mm diameter hole in the side of it.

The hole from the outside
The hole from the outside

The idea of the hole is to allow air to come in and fuel the fire. The theory goes that the air comes in the side, and the resultant fumes (like smoke) leave via the opening at the top. It makes sense because heat rises, and takes all those hot resultant gasses up with it. Note that we don’t really care about the fumes coming off the fire at this point, we just want as much oxygen as possible to get to the coals. If hot exhaust fumes are leaving via the same hole as the oxygen, but going the opposite direction, they will interact with each other, slow each other down, and make the furnace much more inefficient.

Also notice the hole is angled down into the base of the furnace. This isn’t by accident, we want that hole to do two things, pump air into the base of the fire, and not let anything go back up the hole. This hole in the future may contain a fan, to pump more air in. We don’t want the embers flying back up the pipe and breaking the fan during use.

To drill the hole we used a hammer drill bought from Aldi, and a 30mm masonry drill bit, these parts can be pretty cheap if you search around, and the hole doesn’t have to be this exact size. Use what you can find, and make sure you get help when doing the drilling. As always, safety is important, and safety glasses and gloves would be a good idea. if one person steadies the foundry, while the other drills, it is much easier. Go slow, so that the plaster on the inside doesn’t break too much. It is easy to be too eager and create large cracks and chips, which could mean an entire restart.

The hole from the inside
The hole from the inside, notice the dust, and broken parts around the hole.

Although this was a shorter post, the next one will be about the first tests! As always, thanks for reading, and I hope to be along with another update soon. If you guys have any tips, questions, or want to show your foundry, please post in the comments below.

Pioneers in Aviation: The Rolls in Rolls-Royce

Charles Stewart Rolls
Charles Rolls, the co-founder of Rolls-Royce.

Rolls Royce has always been a double sided company, the luxury cars, and the aero engines. Set up by Charles Stewart Rolls, and Frederick Henry Royce, Rolls-Royce Limited was incorporated on march 1906. Starting out as a luxury car manufacturer, they quickly developed a reputation for superior engineering quality. They reportedly developed the “best car in the world”. Henry Royce had already been running an electrical and mechanical business since 1884, and built his first car, the Royce 10 in his manchester factory in 1904. He met C.S.Rolls, an owner of a car dealership, and he was impressed with the quality of the cars. A set of cars (branded rolls-royce) were made, and sold exclusively by C.S.Rolls. This started their partnership. Rolls-Royce Limited set up its first factory in Derby, after an offer of cheap electricity from the city council.

Rolls Royce Racing
Charles Rolls, sits in the back of the 20-horsepower Rolls Royce during the 1905 TT race.

Rolls could be described as a pioneer aviator. As an accomplished balloonist, he made over 170 balloon ascents. He was also a founding member of the Royal Aero Club in 1903, and was the second person in Britain to be licenced to fly by them. That same year he won the Gordon Bennett Medal for the longest single flight time. By 1907 though, he started getting interested in flying, and tried to get his then partner, Royce, to design an aero engine. With Royce not convinced, Rolls, in 1909 bought one of six Wright Flyer’s built by the short brothers. He made more than 200 flights, one of which, on the 2 June 1910, he became the first person to make a non-stop double crossing of the English channel by plane. For this 95 minute flight, he was awarded the Gold Medal of the Royal Aero Club.

Rolls flying
Rolls in the plane he flew across the channel twice in.

On 12th July 1910, Rolls was killed in an air crash at Hengistbury Airfield, Southbourne, Bournemouth. He was 32 when the tail of his Wright Flyer broke off during a display. He was the 11th person to die in an aeronautical accident, and the first ever Briton. A statue of him is in St Peter’s school which was built on the site of Hengistbury Airfield.

Death of Charles Stewart Rolls
Photograph on the front page of the Illustrated London News, 16 July 1910, showing the wreckage of the plane crash which killed Rolls

Pioneers in Aviation: William Boeing

William Boeing was an aviator with a different upbringing than what you would imagine, nothing to do with engineering or even military. Aiming to profit from the Northwest timber industry from an early age, yet he went on to create one of the biggest aerospace companies ever known, one known in almost all households.

William Boeing

Born October 1st 1881 in Detroit, Michigan to a wealthy mining engineer Wilhelm Böing and Marie M. Ortmann. From Germany and Austria. Boeing Sr had made his fortune through timber and mineral rights near Lake Superior in North America. Up until 1899 young Boeing was educated in Vevey, Switzerland, when he returned he changed his name to William Boeing. Studying at Yale University, Boeing left before graduating in 1903. Starting a new life in Grays Harbour, Washington, he aimed to profit from the lands that he had inherited from his father, who had died of Influenza in 1890. He learned the logging business on his own, eventually buying more timber land and adding more wealth to the approximately $1 million estate left to him (around £26.8 in today’s money) by his parents. This included expeditions to Alaska. One of the main reasons for his success was due to him shipping lumber to the east coast using the Panama Canal.

In 1908 he moved to Seattle, to establish the Greenwood Timber company. He started off by living in an apartment hotel, but after just a year he got elected as a member of the Highlands, a brand-new, exclusive residential suburb. During this time, Boeing was interested in boats, and often experimented with boat designs. So much so in 1910 he bought the Heath shipyard on the Duwamish River. This was so he could build a yacht, named the Taconite, after the mineral that made his father’s fortune. His love of aircraft came from a trip while in Seattle in 1909, the Alaska-Yukon-Pacific Exposition was a world’s fair publicizing development in the Pacific Northwest. Boeing was visiting as he had interests in the area. While there he saw a manned flight, and he became fascinated.

Taconite
The Taconite, the 125ft teak yaght built by Boeing

In 1910 Boeing attended an aviation meet in Los Angeles, where he tried to get a ride on a boxy biplane, he didn’t succeed. This didn’t deter him though, he took flying lessons at the Glenn L. Martin Fling School in Los Angeles, and even purchased one of his planes, a Martin TA Hydroaeroplane. James Floyd Smith, a Martin pilot travelled to Seattle to assemble Boeing’s plane and teach him how to fly it. Smith assembled the plane in a tent hanger on the shore of Lake Union, and so Boeing became a pilot. At some point, Boeing’s test pilot broke the plane enough for it to be unusable. Martin informed Boeing that the parts would take months to become available, obviously this was an inconvenience. In 1915, Boeing was introduced to Navy Lieutenant G. Conrad Westervelt, and they soon became close friends. When a mutual friend brought a Curtis-type hydroplane to Seattle later that year, they took turns flying it over lake washington. After just a few trips, Boeing and Westervelt felt that they could build a better airplane. Boeing decided to buy an old boat works on the Duwamish river in Seattle for his factory and set up shop, he was now in the aircraft business.

Boeing Plant
The Boeing Plant on the Duwamish River around 1917

Together with Westervelt they built and flew the B&W seaplane. This was an amphibious biplane that had outstanding performance compared to it’s competitors. This sealed the deal for him, and Westervelt. Together they founded Pacific Aero Products Co in 1916. Their first plane, basically the B&W Seaplane was named the Boeing Model 1. At this time, the world was in the middle of World War 1, and on April 8th 1917, the United States joined the fight. Suddenly there was a need for defence manufacturers. A month later, The name was changed from Pacific Aero Products, to the Boeing Airplane Company. The United States Navy ordered 50 planes from Boeing. When the war ended, the need for military aircraft dwindled, and Boeing started concentrating on the lucrative supply of commercial aircraft. He secured mass contracts to supply airmail, and also created a passenger airline that would later go on to become United Airlines.

B&W Seaplane
The B&W Seaplane, sitting on the water

In 1934 the Boeing company had become massive considering the time. It had an airmail business, commercial airline, manufacturing of planes and many other branches of interest. This sparked controversy in the US government, and he was accused of monopolistic practices. That year the Air Mail Act forced airplane companies to separate flight operations from the manufacturing of planes. At this point Boeing separated himself from the company, and divested himself of ownership. The company was then split into three sections. The United Aircraft Corporation a manufacturing arm, based in the east, Now United TechnologiesUnited Airlines which handled flight operations, and still functions as such, and Boeing Airplane Company which was manufacturing based in the west, this went on to become the Boeing Company that we all know today. By 1937 he had started spending most of his time breeding horses, and the new Boeing Company would not become truly successful until World War 2.

Boeing spent the remainder of his life in property development, and the breeding of thoroughbred horses. He was said to be worried about the tensions in the Pacific Northwest due to WW2. This led him to purchase a 650 acre farm east of Seattle. He called it “Aldarra”. He would go on to die September 28th, 1956 at the age of 74 (a year before the release of the release of the 707). He died of a heart attack while on his yacht. His estate was eventually sold off and turned into a golf course in 2001, but parts still remain today, including Boeing’s main home, and two smaller houses. His house in the Highlands was also listed on the National Register of Historic Places. Also a creek running near his house in the Highlands was renamed Boeing Creek after him.

Boeing Creek
The Creek named after Boeing, running near his house in the Highlands

Pioneers in Aviation: Donald Wills Douglas, Sr

Donald Wills Douglas, Sr was a real aviation Pioneer, from actually viewing the trials of the Wright Flyer, to creating the Douglas Cloudster, and creating the company that would eventually go up against Boeing, building some of the most famous aircraft in the world, even the Saturn V! You could say he has some experience in the world of aviation.

Born April 6th 1892 in Brooklyn New York, the son of an assistant cashier at the National Park Bank. Being an early enthusiast of aviation, in autumn 1908 at the age of 16, he convinced his mother to take him to see the Fort Myer trials of the Wright Flyer. Graduating in 1909, he enrolled in the United States Naval Academy. There are stories of Douglas building model airplanes out of rubber bands and motors in his dormitory at Annapolis. Then flying them on the grounds of the academy’s armory. In 1912 he resigned from the academy to pursue his dream of a career in aeronautical engineering. Applying to jobs at Grover Loening and Glenn Curtiss, and being rejected, he ended up enrolling in MIT. He received a Bachelors of Science in Aeronautical Engineering in 1914. He was the first person to ever receive this degree because he completed the 4 year course in half that time.

Donald W Douglas
Donald W Douglas, Sr holding a prototype of the DC-8 Circa 1955

In 1915 after a year working as an assistant to a professor at MIT, Douglas joined the Connecticut Aircraft Company, and was part of the team that designed the DN-1, the Navy’s first Dirigible (also known as an airship). That august, he left to start working for the Glenn Martin Company, where he was the Chief Engineer, at the young age of 23. During his time there he designed the Martin S seaplane. Not long after that, Douglas left when Glenn Martin merged with the Wright Company. He became the Chief Civilian Aeronautical engineer, of the Aviation section of the US Army Signal Corps. Then a short time after that he moved back to the new Glenn L. Martin Company, as the Chief Engineer, designing the Martin MB-1 bomber in his time there.

Glen Martin MB-1
Glen Martin MB-1 designed by Donald Wills Douglas, Sr

In March of 1920 he gave up his job, which was paying $10,000 a year ($125,000 in today’s money) and moved to California where he had met his wife Charlotte Marguerite Ogg. There he started his own aircraft company, the Davis-Douglas Company. The Davis was from David Davis a millionaire, and his financing partner, who payed $40,000 into the company. The aim of the company was to develop an aircraft that could fly from coast to coast non-stop. This aircraft was called the Douglas Cloudster, and unfortunately failed in its challenge. Although it didn’t achieve the challenge, it was the first airplane that could carry a payload greater than it’s own weight. The failure was too much for Davis, who left the partnership, and in 1921 Douglas founded the Douglas Aircraft Company.

The Douglas Cloudster
The Douglas Cloudster made by the Davis-Douglas company

Douglas was now regarded as a great engineer and a bold entrepreneur. Even though his Cloudster had failed, his new company, the Douglas Aircraft Company was a bit hit. In 1922 he employed 68 people, but with the increase in sales due to WW2, and the increase in passenger planes, the Douglas Aircraft Company became the 4th largest company in the United States. A year and a half before Pearl Harbour, he was already writing about how it “was the hour of destiny for American aviation”. Until 1957 Douglas was President of the Company, until he passed that position over to his son when he retired, and became the Chairman. In 1967 Douglas Aircraft Company Merged with McDonnell Aircraft to form McDonnell Douglas. This company would then go on to merge with Boeing in 1997.

Donald W Douglas, Sr
Donald W Douglas, Sr standing next to a new DC-7

Donald Wills Douglas, Sr died aged 88 on February 2nd, 1981. He is widely regarded as a great engineer and businessman, with plenty of awards to his name, and is listed as 7th in Flying’s magazines 51 heroes of aviation.

The Abandoned Buran Launch Site

So on my recent search for history on the Buran Shuttle, I came across this blog post. Although I had to use the Wayback machine to see it, it shows some great shots of the place where the Buran Shuttle used to launch.

Signpost

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The images show the way that the test site has been left to rust away. Although still obviously a launch site, the stone is breaking, and the machines obviously havn’t been used in a long time.

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As you can see, there is still rubbish piled up, remains of old vehicles, and random scrap metal everywhere. Almost like everyone just up and left. If you have read any of my other posts on the Buran, you will know that is basically what happened. Around 1993, the USSR crumbled and the Buran shuttle programme was left behind. This is why this launch site is still like this, and why urban explorers can go out and take pictures.

On top of this, they found a few other things, including an actual Buran shuttle. Although not a working version, more of a prototype, this shuttle shows how it probably would have looked back in the day. I believe this is the version found at the Gagarin museum in the Baikonur Cosmodrome, close to the launch site found in these pictures. This one is on display to the public, and was refurbished in 2007.

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The last thing that they found was a large machine. More specifically, the machine used to transport the Shuttle to the launch site. A colossal platform, that could move the shuttle and the solid rocket boosters needed for the flight. Unfortunately it was only ever used once in 1988, the only BUran flight ever. So it hasn’t seen much action. It was different to the USA’s Crawler-transporter because it was pulled by 5 diesel trains.

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The Foundry: Part 1 – The First Casting

So we had our aim, and a basic design based off we saw in the videos we had watched. Now we needed to start the process of making it. We made a list of materials we might need, and had a basic look around on the internet, and off we went to the shops. During our travels we visited Screwfix, Wickes, B&Q, Hobbycraft and even Homebase. There were some pretty simple things we needed. Listed below:

  • Sand
  • Plaster of Paris
  • Drill (and drill bits)
  • Steel bucket
  • Safety Goggles
  • Safety Gloves
  • smaller plastic bucket
  • cheap measuring jug

Some of these items you might already own, (and we did) but it was listed as things we needed to complete this stage of the project.

Safety Notice (don’t ignore)

At this point I am going to stress a couple of those boring safety points. We have worked with some materials that could be considered quite dangerous if improperly used. So use safety gloves wherever possible (these can be as cheap as £1.50 in some stores, so there is no excuse!) and goggles and masks are a good idea, especially with dust, and when drilling. If you don’t understand why these are needed, maybe you should stop reading at this point.

Location

We would recommend thinking about where you do this project, there is the potential for spillage of plaster of paris, and that can ruin surfaces; so kitchens are probably out of the question. We recommend outside on a nice sunny day. Its always a good idea to be in a nice open area with plenty of ventilation, even when not working with toxic chemicals, it’s just good practice. We chose out outbuilding, its airy, already has paint stains, and contains all the tools we need as it doubles up as a basic workshop.

The Making

So let’s get on to the bit you care about how we made the foundry. The method starts with mixing together a mixture of 3.5 parts plaster of paris, 3.5 parts sand, and 2.5 parts water. This can be scaled up or down depending on how much you need to make to fill your bucket. We used a standard 14 litre bucket, and a standard liquid measuring jug to mix parts.

14 litre bucket
a 14 litre steel bucket found at most hardware stores
measuring jug
standard measuring jug

A few good tips to add in at this point. You should probably get some friends for this project, a few extra hands can be really useful. while we were making ours, we had one person stirring the mix, and another adding in the parts. Notice below, how many hands are in the images. The other point is to add the sand and plaster of paris before the water. As soon as the water is added, the mix will start the process of setting and you need to get that stuff mixed as fast as possible before it gets too hard. The last point is to mix this a lot, you want it to be thoroughly mixed together, else it could separate in the drying process.

Also, it would be a good idea to wear gloves at this point in the making, plaster of paris can cause burns if it gets in contact with the skin. Read the packaging first, and be careful when handling the powder and the mix.

mixing it together
Mixing it all together

While the mix is almost at its fully ready state, somebody needs to get the smaller plastic bucket, and fill it mostly with water. The amount of water used will depend on your buckets and mix. The water makes it much easier to hold the smaller bucket in place while the main mixture sets. If you get it right, it should not need much force to keep it in place until sufficiently hard.

placing the inner bucket
Placing the inner bucket

Once it is held in place for around 5 minutes it should be hard enough to let go of. if not, it may need to be held longer. You could always put heavy items on top to keep it in place. After a while it should look like the one below. Able to be left without touching, slowly drying.

still drying
Waiting for the mix to dry, but it still hold the inner bucket

Remember that at this stage, it still needs to be left for a long time before we actually take the bucket out, preferably for 24 hours, but it will depend on the mix you made, your climate, the temperature, all manner of things. We recommend leaving it overnight. When you touch the top of the mix, if it is moving then it isn’t ready yet.

The next stage is very fragile though. First empty all the water out of the inner bucket. Then we used a pair of pliers to slowly move the sides of the bucket away from the newly set mix. The bucket was slightly damaged, but with patience it is possible to remove the inner bucket to leave your new fire hole. If it doesn’t collapse in on itself it’s considered a success!

finished
The finished article, ready for fire

Thanks for reading this post, I hope to be posting some more updates about our foundry in the coming weeks, so watch this space. Also, if you have been making your own foundry, leave a comment below. We would love to hear from you.