The Big Slide Thread

[GreenTwin]

This is probably a matchplate for an piece of an electric motor.
Two sprues, or perhaps one sprue and one riser.
My guess two sprues, and they did a simultaneous double pour, which I have seen foundries do, since it is much easier to melt and pour using two smaller crucibles, instead of one large unwieldy crucible.
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[GreenTwin]

A differential housing pattern, made from the old-school (nowdays exotic, rare, sometimes even illegal) hardwood.
Someone put a lot of time into figuring out the split lines for this pattern.
I am not sure I can spot them all.
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[GreenTwin]

Notes written on the matchplate.
Looks like the material to be used for the casting (20% A% nickel-moly), and the world "Pack".
"3/4 Top Riser"; not sure exactly what that means; something about the riser.

I have started writing all sorts of notes on my flasks, to make sure I don't reverse the multi-flask pieces, and also notes about how much sand goes into each flask piece, since the binder has to be measured out per sand weight.
I sometimes put the casting weight, and the total poured metal mass on the flask, since that also has to be weighed out before a melt.
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[GreenTwin]

These could be the patterns for an engine, but are probably patterns for something like an air compressor.
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[GreenTwin]

Says "automotive intake patterh".
I have seen some pretty intricate V-8 headers cast in iron.
It is amazing what can be cast when you add phosphorus to an iron melt.
Back in the day, practically everything was cast in iron, including toys, etc.
Aluminum was somewhat rare and exotic, although they did make old castings from it, such as the Wright airplane engine.
There is a ytube video of someone casting a recreation of that engine.
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[GreenTwin]

Wright Flyer crankcase casting.
Looks like our own member and MEB legend Mike Rehmus made this video.
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[GreenTwin]

The Wright engine.
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[Richard Hed]

When I started college in 1976, I walked into the first class, and they had one of these big slide rules hanging in the front of the classroom.
The teacher said "Everybody is going to need a good slide rule for this class".
I walked to the registrar's office after class and quit school.
I worked odd jobs of all types for two years, and then decided to attempt school again.
I went in the same class room, and there was the dreaded monster sliderule, but this time the teacher said "Everybody is going to need a good calculator".
"Saved by the calculator" I said to myself, and the rest is history.
I had a math phobia, and so I had to get over that first, but I still can't use a slide rule, although I have read the instructions.
It seems uber clunky, but the "slide-rule-boys" as we called them in the day, could use them very effectively.

Seemed more like trying to make your own arrowheads out of rock, instead of just going hunting with a rifle.
Hard to believe they went to the moon using slide rules.
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I have three of them and I likes 'em, but I use a calculator.

 

[Richard Hed]

The Wright engine.
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Are there drawings of this engine available?

 

[GreenTwin]

Are there drawings of this engine available?

I seem to recall someone building a model of this engine.
Perhaps it was published in MEB; Mike Rehmus would know.
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[Richard Hed]

This one is in the Czech Republic, so it would be a long drive/swim.
This has the look and feel of a full sized functional engine, but some of it looks a bit like a model engine too.
Looks old.
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It's got slide valves and a governor, must be an engine.

 

[GreenTwin]

It's got slide valves and a governor, must be an engine.

It is a very nicely detailed engine, with the wood lagging, and especially the flywheel.
Simple expansion, not compound.
The replica brick floor tiles makes me think it was a model engine.
Has an impressive governor assembly.
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[a41capt]

When I started college in 1976, I walked into the first class, and they had one of these big slide rules hanging in the front of the classroom.
The teacher said "Everybody is going to need a good slide rule for this class".
I walked to the registrar's office after class and quit school.
I worked odd jobs of all types for two years, and then decided to attempt school again.
I went in the same class room, and there was the dreaded monster sliderule, but this time the teacher said "Everybody is going to need a good calculator".
"Saved by the calculator" I said to myself, and the rest is history.
I had a math phobia, and so I had to get over that first, but I still can't use a slide rule, although I have read the instructions.
It seems uber clunky, but the "slide-rule-boys" as we called them in the day, could use them very effectively.

Seemed more like trying to make your own arrowheads out of rock, instead of just going hunting with a rifle.
Hard to believe they went to the moon using slide rules.
.

I too was worried when the instructor said we would need an E6B flight calculator in aviation ground school. I never learned to use a slide rule and worried the E6B would tax my mathematical shortcomings.

I was pleasantly surprised with how quickly I caught on, and reconsidered learning the slide rule.

It didn’t take long for technology to catch up in both areas however, and a scientific calculator (and eventually my iPad) won out!

John W

 

[Richard Hed]

It is a very nicely detailed engine, with the wood lagging, and especially the flywheel.
Simple expansion, not compound.
The replica brick floor tiles makes me think it was a model engine.
Has an impressive governor assembly.
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Definitely. Also looks like made a long time ago by the rust.

 

[GreenTwin]

E6B flight calculator

I had to look that one up.
Found a picture below.

And they forced us to use a Smith Chart in the field theory class.
I must confess, I never got the feel for using a Smith chart.
I understood that it was a tool used to solve fields problems, but it also has sort of a corn maize feel to it too.
I have seen others use a Smith chart, such as my profesor, and so I know it works.
The first thing that came to mind when I saw a Smith chart was "what the flock are they trying to make use do now?".
Sort of like Chinese water torture; the things they use to force us to use.

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[GreenTwin]

Definitely. Also looks like made a long time ago by the rust.

Steam engines ruled supreme for perhaps 100 years; the motive power that brought us into the 21st Century.
Articles about them filled many technical books and magazines of the day.
The steam engine books written by prestigious university professors were often steeped in complex calculus formulas.

Many of the best technical minds in the world focused on advancing steam engine design for many years, especially prior to about 1896.
1896 was when Westinghouse demonstrated his 3-phase power distribution system, which was the beginning of the end for reciprocating steam engines.
Steam turbines still rule some of the power world.

Steam engines were everywhere, used for everything, and so people were exposed to them much more than today.
And it was much more common to be able to just walk into places, with little or no security.

I recall going to the airport when I was young, and every plane on the apron was a DC3.
There were no jet commercial airliners in common use in this area.
When a DC3 engine would start, it would billow out clouds of smoke, and sprew out oil, which would stream down the cowling.
I could not believe people actually flew on planes that had an engine that had so much trouble starting.
I remember thinking "Dang, I hope they make it".

And you could just walk out on the ramp and greet folks.
Airplanes had rolling stairs, and to board an airplane, you had to go outside, and climb the stairs.
You could basically go about anywhere you wanted to go at airports in the early 1960's.
And people dressed up like they were going to church when they would fly.
Coats and ties and such.

I am not even sure if the cabins were pressurized back then.
A friend of mine's dad was a radial engine mechanic for one of the airlines, and he decided he wanted to become a pilot, and so he got his license, and flew commercial until he hit 65 I think, which is mandatory retirement.
That guy could tell some stories.
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[SmithDoor]

1906 Cushman 3hp for sale on ebay.
Not my photos.
I don't recall ever seeing a model of this engine built.
It is so small as to almost qualify as a model itself.

My guess is this is a 2-stroke, much like the Maytag variety that were so popular in the day.
I was never into two-stroke engines, except on motorcross and enduro bikes, where they made some really nice ones like the CR500, and the Yamaha 400cc enduro, which had a ton of torque.

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Nice looking engine

Dave

I had to look that one up.
Found a picture below.

And they forced us to use a Smith Chart in the field theory class.
I must confess, I never got the feel for using a Smith chart.
I understood that it was a tool used to solve fields problems, but it also has sort of a corn maize feel to it too.
I have seen others use a Smith chart, such as my profesor, and so I know it works.
The first thing that came to mind when I saw a Smith chart was "what the flock are they trying to make use do now?".
Sort of like Chinese water torture; the things they use to force us to use.

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I use E6B a lot at one time .
It so simple to use
It faster than cellphone.

Just look at huge engines B29 around 2,500hp times 4 or toal of over 10,000 hp and simple computer E6B was to guide . The B29
Power ranged from 2,200 to 3,700 hp.
The high total is 14,800hp

If only the liberty ships use this size.

I know some have wonder how America could start building jets. It is simple we built Turbo chagers. Basically remove the engine add a combustion chamber now we call it a tubrojet engine. Now look at all fun gone.

FYI
They have apps on E6B for cellphones.
Basically it figures the true ground speed and the direction to fly the aircraft for heading really want.
Then will do Dead Reckoning Calculations.

Just think of fly a B29 after building the engines or continental engines. The E6B the other end a part of navigation side.
I have found interesting after build or rebuilding a engine how was use and tools they used.
Then you simply computer like E6B was part that big engine.

You engine build can be more interesting by under standing other aspects and why we need the engines.

Have fun building

Dave

 

[tiger12506]

When I started college in 1976, I walked into the first class, and they had one of these big slide rules hanging in the front of the classroom.
The teacher said "Everybody is going to need a good slide rule for this class".
I walked to the registrar's office after class and quit school.
I worked odd jobs of all types for two years, and then decided to attempt school again.
I went in the same class room, and there was the dreaded monster sliderule, but this time the teacher said "Everybody is going to need a good calculator".
"Saved by the calculator" I said to myself, and the rest is history.
I had a math phobia, and so I had to get over that first, but I still can't use a slide rule, although I have read the instructions.
It seems uber clunky, but the "slide-rule-boys" as we called them in the day, could use them very effectively.

Seemed more like trying to make your own arrowheads out of rock, instead of just going hunting with a rifle.
Hard to believe they went to the moon using slide rules.
.

I was fascinated by slide-rules and learned how to use one, and then used it exclusively for a Physics I, and Chemistry course in college. (I'm a 90s kid) It turns out, that the types of problems you have to solve there lend themselves very well to the slide rule.

To use one, you have to understand that log(A*B) = log(A) + log(B), and also understand that the calculations across powers of ten result in the same digits. i.e. 25 * 4 = 100, but also 0.25 * 0.4 = 0.100 Same digits, but the decimal place moves. Tracking the decimal place (in your head) as you continue calculations is the toughest part, but it isn't really that difficult.

Since the "rule" of the slide rule is laid out logarithimically, (i.e. the lines get closer together the closer you get to the right), when you add together the distance from the edge of the outer to the edge of the inner, you are actually adding together log(A) and Log(B). So multiplication is done just by "adding" the two distances together, i.e. looking to see what number across from B on the A scale.

Physics & Chemistry are a bunch of calculations that are a string of multiplication and division. And because A*B/(C*D) = A/B * C/D freely, you can just accumulate the end result by adding and subtracting on the slide rule, while keeping a running total of what decimal places you are adding on/off.

The slide rule is one of the reasons that "scientific notation" is a thing. As you write a number in scientific notation, you are effectively preparing it *directly* for being applied to the slide rule. You see immediately the whole+partial number that is the distance you are going to slide on the rule, and you see directly the powers of ten that you are tracking during the calculation.

Further, because of the limitations of precision (you can only slide the rule so precisely. Maybe you can enter 1.27, but not 1.275); the slide rule naturally maintains significant digits for you. You don't have to wonder if you have bonkers unrealistic precision in your result. (A simple example: 1 / 3 = 0.3333333333333 on a calculator, but there is no way you could guarantee OR measure that accurately). The slide rule will never give you a result like that beyond your significant digits.

It is actually a beautiful instrument, but I admit it has its niche in real-world applications like physics and chemistry, and not more abstract subjects like maths.

 

[GreenTwin]

I was fascinated by slide-rules and learned how to use one, and then used it exclusively for a Physics I, and Chemistry course in college. (I'm a 90s kid) It turns out, that the types of problems you have to solve there lend themselves very well to the slide rule.

To use one, you have to understand that log(A*B) = log(A) + log(B), and also understand that the calculations across powers of ten result in the same digits. i.e. 25 * 4 = 100, but also 0.25 * 0.4 = 0.100 Same digits, but the decimal place moves. Tracking the decimal place (in your head) as you continue calculations is the toughest part, but it isn't really that difficult.

Since the "rule" of the slide rule is laid out logarithimically, (i.e. the lines get closer together the closer you get to the right), when you add together the distance from the edge of the outer to the edge of the inner, you are actually adding together log(A) and Log(B). So multiplication is done just by "adding" the two distances together, i.e. looking to see what number across from B on the A scale.

Physics & Chemistry are a bunch of calculations that are a string of multiplication and division. And because A*B/(C*D) = A/B * C/D freely, you can just accumulate the end result by adding and subtracting on the slide rule, while keeping a running total of what decimal places you are adding on/off.

The slide rule is one of the reasons that "scientific notation" is a thing. As you write a number in scientific notation, you are effectively preparing it *directly* for being applied to the slide rule. You see immediately the whole+partial number that is the distance you are going to slide on the rule, and you see directly the powers of ten that you are tracking during the calculation.

Further, because of the limitations of precision (you can only slide the rule so precisely. Maybe you can enter 1.27, but not 1.275); the slide rule naturally maintains significant digits for you. You don't have to wonder if you have bonkers unrealistic precision in your result. (A simple example: 1 / 3 = 0.3333333333333 on a calculator, but there is no way you could guarantee OR measure that accurately). The slide rule will never give you a result like that beyond your significant digits.

It is actually a beautiful instrument, but I admit it has its niche in real-world applications like physics and chemistry, and not more abstract subjects like maths.

Thanks much for this very clear and concise explanation.
A very powerful analytical tool for sure, and so simple on the face of it, ie: a sliding stick with some lines scribed on it.
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