Sunday, November 11, 2007
Monday, September 10, 2007
It sure makes newspapers more appealing.
(Vietnamese proverb, as quoted by Vo Dong Giang.)
Do not fear when your enemies criticize you. Beware when they applaud.
Friday, August 31, 2007
Thursday, August 23, 2007
Wednesday, August 08, 2007
The great liability of the engineer compared to men of other professions is that his works are out in the open where all can see them. His acts, step by step, are in hard substance. He cannot bury his mistakes in the grave like the doctors. He cannot argue them into thin air or blame the judge like the lawyers. He cannot, like the architects, cover his failures with trees and vines. He cannot, like the politicians, screen his sort-comings by blaming his opponents and hope the people will forget. The engineer simply cannot deny he did it. If his works do not work, he is damned.
- Herbert Hoover, Opening Quote of Chapter 5, Introduction to Aeronautics: A Design Perspective by Steven Brandt et Al.This quote came up recently in a discussion with a coworker. It seems even more important than usual given last week's news from Minnesota.
Thursday, July 26, 2007
How to Give A Cat A Pill
- Pick cat up and cradle it in the crook of your left arm as if holding a baby. Position right forefinger and thumb on either side of cat's mouth and gently apply pressure to cheeks while holding pill in right hand. As cat opens mouth pop pill into mouth. Allow cat to close mouth and swallow.
- Retrieve pill from floor and cat from behind sofa. Cradle cat in left arm and repeat process.
- Retrieve cat from bedroom, and throw soggy pill away.
- Take new pill from foil wrap, cradle cat in left arm holding rear paws tightly with left hand. Force jaws open and push pill to back of mouth with right forefinger. Hold mouth shut for a count of ten.
- Retrieve pill from goldfish bowl and cat from top of wardrobe. Call spouse from yard.
- Kneel on floor with cat wedged firmly between knees, hold front and rear paws. Ignore low growls emitted by cat. Get spouse to hold head firmly with one hand while forcing wooden ruler into mouth. Drop pill down ruler and rub cat's throat vigorously.
- Retrieve cat from curtain rail, get another pill from foil wrap. Make note to buy new ruler and repair curtains. Carefully sweep shattered figurines and vases from hearth and set to one side for gluing later.
- Wrap cat in large towel and get spouse to lie on cat with head just visible from below armpit. Put pill in end of drinking straw, force mouth open with pencil and blow down drinking straw.
- Check label to make sure pill not harmful to humans, drink 1 beer to take taste away. Apply Band-Aid to spouse's forearm and remove blood from carpet with cold water and soap.
- Retrieve cat from neighbor's shed. Get another pill. Open another beer. Place cat in cupboard and close door onto neck to leave head showing. Force mouth open with dessert spoon. Flick pill down throat with rubber band.
- Fetch screwdriver from garage and put cupboard door back on hinges. Drink beer. Fetch bottle of scotch. Pour shot, drink. Apply cold compress to cheek and check records for date of last tetanus shot. Apply whiskey compress to cheek to disinfect. Toss back another shot. Throw tee-shirt away and fetch new one from bedroom.
- Call fire department to retrieve the friggin' cat from tree across the road. Apologize to neighbor who crashed into fence while swerving to avoid cat. Take last pill from foil-wrap.
- Tie the front paws to rear paws with twine and bind tightly to leg of dining room table, find heavy duty pruning gloves from shed. Push pill into mouth followed by large piece of steak. Be rough about it. Hold head vertically and pour 2 pints of water down throat to wash pill down.
- Consume remainder of Scotch. Get spouse to drive you to the emergency room, sit quietly while doctor stitches fingers and forearm and removes pill remnants from right eye. Call furniture shop on way home to order new table.
- Arrange for Humane Society to collect mutant cat from hell and call local pet shop to see if they have any hamsters.
How to Give a DOG a pill
- Wrap it in bacon.
Thursday, July 05, 2007
I've seen little chapels/churches before. I know that when you see a sign for a little church you can usually expect something like this.
This is "The Little Brown Church" just north of Waterloo Iowa. It is a typical small country church.
But this is the Little Chapel Church of Southern Illinois
No, the little church is not behind that humongous building. That building really is The Little Chapel Church
After a closer look we determined that the building was about 400 feet long by 200 feet wide with 37 separate air conditioning units! There is also a day care center with a playground, a huge parking lot, and a bus barn.
I think the "Little Chapel Church" is a very nice name, but as a description it requires more than a little imagination!
Monday, July 02, 2007
In my old technology posts thus far I have talked about power sources, but i have yet to talk much about how this power is utilized. In the modern world where every little gadget, power tool, and machine seems to be driven by electricity, it's easy to forget that all of that power has to come from somewhere. Electric cords just blend into the background, and battery powered devices eliminate the cords entirely, but this is an incredible luxury compared to what was previously done to operate machines.
Look back at my post on the Aldie Mill in Virginia. You'll notice the power from the waterwheel is transferred directly to the millstones by way of large shafts and gears. This works well for one or two devices, but what if you want to transfer that power to multiple machines? When the mill was upgraded over the years, it began to use roller mills, similar to these. To completely process grains, you typically needed several units. In order to power them, the mill began to use line shafts.
Here, one of the waterwheels is connected, by way of a large pair of reduction gears to a pulley. This would, when operational, have a large belt connecting it to a much smaller pulley on another shaft. That shaft could then be extended to nearly the length of the building. Wherever power was needed for a roller mill, fan mill, or other device, a pulley was placed on the shaft. That pulley, and another belt, would transfer power to the machine below.
Of course if you can do this with water, you can do this with steam or gas engines as well. This is why most older engines either had a large pulley attached to the crankshaft or else had a wide flat flywheel that could be used to run a belt.
To make this a little easier to understand, let's look at a model.
This miniature machine shop is made up mostly of kits from PM Research who display and sell their wares at the Old Threshers Festival. Here, a model steam engine is connected to a line shaft, via a belt.
This shaft runs the length of the building, and is connected to other shafts and machines, all of which could be powered by the engine at the same time.
Of course, this has some potential complications. Very seldom will all of the machines in a shop need to run at the same speed, yet when they are all running at the same time, you can't just change the speed of the steam engine to suit one particular machine. This is why different sizes of pulleys are used. Two pulleys of different sizes act in much the same way that two gears of different sizes will act. A large pulley when connected to a smaller pulley, will cause the smaller pulley to spin at higher RPMs. By using this knowledge, you can have a line shaft that spins at a set speed throughout a facility, and yet have machines running at various different speeds.
To complicate matters further, some machines needed the ability to be adjusted to run at multiple speeds.
You may notice in this picture that some of the machines shown have a pair of multiple diameter, almost conical pulleys. These are connected with a thin belt that runs between one pair of pulley diameters at a time. Adjusting the belt to one set of diameters or another, changes the diameter ratio and therefore the RPM ratio of each of the pulleys. So each diameter on each pulley represents its own speed, almost like a modern selectable gearbox. (Incidentally, if you make the pulleys perfectly conical then you would be creating a continuously variable transmission.)
Sometimes it was necessary to stop a machine entirely. This created another problem because nobody wanted to shut down an entire factory just to work on a single machine. It became necessary to isolate machines from the line shaft. I'm sure there were several possible methods for this, but the simplest was simply to move the belt to an idler pulley. Either on the machine or on the line shaft, a free spinning pulley could be mounted so that when a machine needed to be stopped, the belt was simply moved from the main pulley to the idler pulley, where it could not transmit any power. Similarly, a belt might be allowed to go slack, so that there was not enough friction between the belt and the pulley to transmit any significant force. Both methods worked, even though they were far from perfect.
Still, systems like this were used in all manners of facilities from machine shops and factories, to grain or textile mills, and other manufacturing facilities. Over the years, they would be used with waterwheels, steam engines, gas engines, diesel engines, and eventually, they would even be adapted to run under power from large electric motors.
The line shaft system did have drawbacks. All of the moving parts created plenty of friction, so efficiency suffered. It also required considerable time and effort to make sure that all of the line shafts were well maintained and lubricated. Safety was one of the primary drawbacks of a line shaft operated facility. Even though machines could often be disconnected, it was rare to completely shut down a system, so people were often injured by working on moving equipment or trying to put belts back on pulleys after they had slipped off. Unguarded belts and pulleys can be particularly hazardous because of their ability to catch appendages or loose clothing and pull people into moving equipment. The same can also be said for the line shafts themselves. Keeping out of moving machines required considerable care and attention, both of which were hard to come by in the typical old bustling factory.
All of these problems could not be ignored, and when electric motors became smaller, economical, and readily available, factories began using machines powered by electric motors instead. Sometimes, entirely new machines were purchased that had motors built in. In some cases though, shops would refit their existing equipment to run without a line shaft.
Here is an example of an old drill press that would originally have be run by a belt from a line shaft. It has since had an electrical motor mounted on it, which turns the pulley that was originally used to power the drill. The adjustable speed pulleys are still intact, and the old mechanism has not been changed. In fact, except for the motor and an on/off switch, this drill press is virtually identical to what would have been found in any old machine shop. Home made conversions like this one, no doubt offered a cost effective way of running old equipment, even when maintaining an old line shaft system became impractical.
Today, this sort of system has faded out of use in most places. Your best chance of seeing a line shaft driven shop would be in a museum. If you get the chance, though, it's interesting to see a shop like this in action.
For a much more mathematical look at this topic, take a look at the belt and pulley page over at Harry’s Old Engine
Monday, June 25, 2007
Friday, June 08, 2007
Tuesday, May 29, 2007
"For the want of a nail, the shoe was lost; for the want of a shoe the horse was lost; and for the want of a horse the rider was lost, being overtaken and slain by the enemy, all for the want of care about a horseshoe nail."
-- Benjamin Franklin
Monday, May 28, 2007
I'll be putting up a few posts soon, Starting with a brief essay I've been contemplating for a few months: The Mundane Detail
If you’ve seen the movie ‘Office space’ then you probably remember the scene when the three main characters discuss how their money skimming scheme has gone awry and discover they will probably be going to prison. Michael, reveals what has given them away…
“I always do that. I always mess up some mundane detail.”
Yep, $300,000 and a prison sentence, traced back to a ‘mundane detail’
It’s the sort of thing that I have encountered too often. People don’t place value on things that seem simple or ordinary, but these are the things that often end up being important.
If there’s a lesson to be learned from this, I suppose it is that details can be simple, and even boring, and yet still be insanely important to your work or others, so try to stay sharp, and don’t overlook the little stuff.
An afterthought: I am not immune to this problem myself. I would like to comfort myself with the thought that the details I miss are more subtle than the examples listed here, but the truth is that nobody is perfect. Of course that doesn’t mean we can’t strive for perfection.
Wednesday, April 25, 2007
I was sitting in
The whole region is highveld grassland, meaning that it’s a very arid, somewhat prairie like environment with few trees and plenty of grass fires (which are often allowed to run unchecked if they do not threaten an inhabited area. Combine that with the red soil, and it looks like
This particular region has basalt (igneous) inclusions into a sandstone (sedimentary) layer. Consequently, over the years, the softer sedimentary rock has eroded away, leaving rather prominent peaks and ridges made of basalt and a thin layer of soil.
The higher regions of the reserve have relatively limited wildlife activity, because they are so dry and sparsely vegetated that there is little cover and less food for herds. Of course if you get close to a watering hole, then you usually see quite a bit of wildlife.
In this reserve is mostly populated with eland, wildebeest, and zebras. Occasionally you will see some Hyenas, but you don’t encounter large animals like elephants and rhinos or predators like lions. Of course this lack of the most dangerous African animals probably explains why there are so many hiking trails in the area.
I did get to see one predator while I was in
It played just like an ordinary house cat, but I would really hate to get it mad even at a fairly small size like this.
I did get one extra treat on this trip, thanks to a colleague at work.
A fun as it might be playing with tiger cubs and running around nature reserves with a camera, I have finished (for the time being) my work overseas, and now I am back in
Friday, April 13, 2007
I've just spent a month in a place where checking my email usually involved checking for a dial tone. I have now left South Africa for Singapore where I will be spending a few days before continuing on my way.
The trip so far has actually been rather nice, though far from relaxing. South Africa was rather enjoyable, though I won't go into the details just yet.
I have some photos to share and will post them in a couple of days when I get a little time away from the factory. I the meantime, I will leave you with this.
Friday, March 09, 2007
Most travel is best of all in the anticipation or the remembering; the reality has more to do with losing your luggage.
As you might have guessed, I am travelling again, and this time I'm out of the country. I landed in Johannesburg yesterday and expect to be spending a few weeks in the area (on business of course.)
I'll put up a few posts whenever I get the chance, and hopefully I'll get to do just a little sightseeing before I leave.
Thursday, March 01, 2007
It looks like we're getting the first of the spring storms in Chicago. I'm not sorry to see winter go, but I am sorry to be leaving right as the weather gets nice. Next week I'm starting off on a trip to the southern hemesphere and equator. It should be fun. Too bad I won't get back until mid to late April.
Friday, February 23, 2007
Just the other day I glanced at the cover of the Model Railroader magazine and was delighted to see a cover story touting a tour of a largely scratch-built layout. In years past this might not have made headlines as virtually every layout they featured was full of scratch-built structures. More and more though it's possible to recognize the models in the MR articles.
This layout featured a number of pieces that were hand built out of highly detailed craftsman kits or constructed completely from scratch. This gave everything a very fresh, unique look and made it possible to experience the sort of suspense of disbelief that allows you to look at the railroad as though it is real. Sadly, it seems as though thisapproach to the hobby is largely disappearing
Recently I visited the "Great Midwest Train Show" in DuPage County. After searching the show and finding only a couple of antique kits that interested me, I struck up a conversation with one of the dealers about how hard it was to find craftsman kits andscratch-building materials. It was his opinion that quality kits were only going to get harder to find while more and more ready to run and quick assembly kits were going to take over the market.
After thinking it over for a bit I had to agree with him
Several years back, I purchased what was, at the time, the only commercially available kit for a CB&Q waycar. It was a LASERkit model which means that it was mostly wooden pieces cut on a computerized laser cutter. It was quite complex and took several hours on several evenings to complete. It was quite satisfying to see it finished. A year or so later, Walthers came out with the same waycar in a nearly ready to run version. The price wasn't too out of line with what was already on the market, but the new kit could be put together in about a half an hour with a bottle of superglue. Now the model is down to about half of the original cost.
The wooden model is the one with the handrails removed.
Here's an example of what most people would consider a craftsman kit.
In the 1930s and 1940s when this kit was originally sold, it was considered a pretty standard kit. I picked this up at a model show in Green Bay a few years ago in roughly this condition. Apparently theprevious owner had done some work then abandoned it when it didn't run smoothly. It turned out that the mechanism that held the brushes against the armature of the motor was damaged (and poorly suited to the task.) So I simply replaced it with a spring system of my own (loosely based on other designs) and now it runs great.
I plan to build up this kit to a finished model as soon as I get a chance to sit down and really work on it. I could drop about $160 on a modern, ready-to-run model that would probably have a quieter motor and marginally smoother operation, but that defeats the purpose of having a hobby. If all I did was buy the models I wanted, it would just be collecting, and not model railroading.
So if I may offer a bit of advice, if you have a hobby (and almost everyone does) make it worthwhile, and put some actual effort into what you do. If it's collecting, learn some history about what you have, not just the values. If it's a craft, make something the hard way and see how you like it. I bet you'll have more fun that way
Friday, February 02, 2007
Saturday, January 13, 2007
Thursday, January 11, 2007
In my earlier post ‘The Powerhouse’ I covered a little about stationary steam engines and the technology behind them. If you’ve already read that, or if you know a few things about steam engines, you’ll probably find that you understand a great deal about antique gas engines as well.
Gas engines (or more appropriately, combustion engines) were basically the next evolutionary step in the development of machinery and machine operation. They were often made in a format very similar to that of the existing steam power of the day. A cylinder was mounted (often horizontally) on a frame, it held a piston connected to a pushrod that turned a crankshaft, flywheel, and pulley.
The general appearance of steam and gas engines is often quite similar, but the method of obtaining power is somewhat different. Naturally, while a steam engine’s power is supplied by a boiler, a gas engine relies upon some combustible liquid or vapor being ignited in the cylinder. Unlike most steam engines, the power is supplied on one side of the piston only. In fact, while a steam engine can be powered through almost all of it’s stroke (except the very end) a typical gas engine ran on a 4 cycle system where power could only be provided about a quarter of the time. Like many steam engines, this energy was used to turn a flywheel which smoothed out the flow of power from the engine.
There were other differences as well. Combustion can produce high pressures from relatively small amounts of fuel and air, so the huge pistons and valves seen in steam engines were not necessary. Of course the power stroke of a combustion engine can be rather violent so sturdy bearings, and crankshafts were necessary.
The control methods for these engines also had strong ties to their older steam engine counterparts. Typically a centrifugal governor was mounted somewhere on the engine either by taking power from the crankshaft, or by putting governor weights directly on the flywheel. Here’s an example.
On this engine, made by the Abenaque Machine Works, a small driveshaft is geared to the main crankshaft (behind the flywheel) This shaft has two weights (painted red) which are pinned in place so that they can pivot away from the shaft when they’re spinning quickly or be pulled inward by a spring at slower speeds. This is the same principle as in the steam engine governor from my ‘Powerhouse’ post. The way this principle is used, however, is noticeably different.
Achieving reliable and controlled combustion requires a consistent fuel supply and the ability to thoroughly mix the fuel with air. Fuel injection was unheard of when engines like this were first being built. Even good adjustable carburetors weren’t available for the early years of these one cylinder machines, so creating a reliable and controllable fuel supply for every stroke was not really an option. Even if the designers of the first gas engines had been able to provide a precise throttle and carburetor system, it’s questionable it would have been a success. Many engines were expected to run on multiple fuels, including gasoline, various grades of oil, or natural gasses. This no doubt created too many variables for early gas engine technology to compensate.
The solution found was the hit and miss style of operation. On a 4 cycle engine of any kind, it’s possible to have a power stroke on every second complete revolution of the crankshaft, but what’s the point of having a power stroke when you still haven’t used the energy from the last one? When a gas engine provides more power than is needed, it’s simply stored in the flywheel, so that the engine keeps running regardless of whether or not another power stroke is made. Because of this, all you have to do is keep the exhaust valve open to relieve pressure in the cylinder, and the engine will coast for a while after making a power stroke.
Here’s how it happens. An engine is running at the speed set by the governor. A load is applied to the engine (usually by way of a belt to some other machine.) This slows the engine down, so the weights of the governor are pulled inward by a spring or counterweight and this triggers some type of cam or linkage. The engine’s exhaust valve closes, the intake valve opens briefly to allow fuel and air to be drawn into the cylinder, and the piston compresses the mixture in the cylinder. A spark from the magneto and spark plug ignites the fuel and the piston completes its stroke under power, causing the crankshaft and flywheel to accelerate. The acceleration causes the weights on the governor to be pulled outward. The exhaust valve opens to allow the spent fumes to escape, and it is held open because the governor is now moving fast enough that it is not necessary to make another power stroke. And the cycle begins again.
The sound of an engine like this is pretty unmistakable because you can hear it fire once and then it will usually ‘chuff’ softly several times as the piston cycles with the exhaust valve open.
The introduction of combustion engines created the need for another design change. The hottest part of a steam engine is steam that comes from the boiler. Even a boiler with a superheating system would never produce steam hot enough to melt steel. (If it did, it would melt the boiler.) Consequently, the steam cylinders, though hot to the touch, did not require a cooling system to maintain the integrity of the metal. Gas engines, however, had the ability to produce temperatures that would soften or melt most steels. This meant that new systems had to be invented to keep the gas engines cool as they ran.
A simple method of keeping a gas engine cool was to add cooling fins. Much like the computer cooling systems of today, this approach increased the surface area available to expel heat by means of heat radiation or convection. Such designs were often quite simple as in the case of this model gas engine, which has a set of fins around the outside of the cylinder.
Another method of cooling was commonly used on gas engines to keep them from overheating; the cooling tank. The basic explanation is that if you stick a pot of water on top of a gas engine’s cylinder, it won’t overheat because as soon as the water gets to 212F the water will start to boil away and take the excess heat with it.
The design of the tank varied from engine to engine, sometimes becoming a bit artistic, but typically it was just a rectangular tank mounted on top of a cylinder. Of course these engines were made with a water jacket around cylinder to cool it from all sides. On smaller engines, it was even possible to build the engine so that the tank was the only thing visible, and the cylinder simply ran through the tank. If extra cooling was needed, water could even be circulated through a radiator, much like on a car.
Of course I can't talk about cooling without mentioning this circa 1912 Aermotor. In this case, a tank with cooling fins was mounted vertically on top of the cylinder. This was likely intended to help increase the amount of convective heat loss, because the air which is heated by the fins will naturally tend to rise, creating more circulation along the length of the fins. Also, this design shed enough heat that you didn't continually need to add more water to the hopper (which was quite common in open hopper engines)
Of course, these fins also have the effect of making the engine look a bit outlandish.
Over all, gas engines tended to remain fairly simple in design for many years. This could likely be attributed to the fact that farms were the most common place to use a gas engine of this sort. If the engines were made too complex or require too much maintenance, they lose their usefulness in this environment. Eventually carbureted engines would become more common, as the improvements in design and manufacturing made it possible to control an engine by its fuel supply rather than simply using hit and miss operation. Much of this development was no doubt driven by the development of automobiles and tractors which required more powerful, smoother running engines. Still, these small engines were a familiar sight until electric motors became strong enough (and common enough) to be used in their place.
While your typical combustion engine was found on a farm, powering small pieces of equipment, there were other engines which were much larger and much more complex. Larger engines were needed in many applications. Factories, mills, power plants, ships, and other heavy equipment needed power too, and although they had relied upon steam in years past, many of them converted over to combustion engines.
These applications required plenty of power and long hours of operation, meaning that the engine had to require very little time for servicing and repairs. This is where diesel engines really shined.
Some of these engines still had the same cylinder and flywheel arrangements as their barnyard counterparts, but they they were usually noticeably larger, and it was fairly common to see them made with multiple cylinders.
These engines are not easy to come by, but when you get a chance to see one in operation it’s quite impressive. Here’s an example of a page engine which was originally used to power a drag line.
Today this beast resides in the powerhouse museum on the Mt. Pleasant fairgrounds. It’s a two cylinder diesel manufactured by Page Engineering Company (Chicago IL) where it has been restored to running condition. This engine produced 110 hp. When you consider the horsepower cranked out by today’s automotive engines, this may seem rather small, especially for an engine with 13” bore cylinders. Still it was quite powerful for an engine in its time.