
Animated Engines - d4vlx
http://www.animatedengines.com/
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bliti
Which of the petrol powered engines scales best (those used in cars)? This is
an open question to all. I'll take a swing at it.

I've worked with 2 strokes, 4 strokes (including Miller Cycle versions), and
rotaries.

The two strokes hit a wall pretty quickly. They are very rev-happy, but their
combustion leaves a lot to be desired. Most lack conventional valves and rely
on ports to move the mixture around. You can supercharge them, but I've never
been able to do so properly. Once the engine size starts to increase, their
main advantage (RPM capabilities) start to diminish. Plus their combustion is
not very clean, due to the lubrication being part of the fuel. They are fun
when modified, but noisy. Ask my neighbor (who gets to enjoy the glorious
sound of the modified 2 stroke in my weed whacker).

The 4 strokes suffer from harmonics, weight, and packaging issues. But they
can be supercharged without much problems. You can get at least 100 HP/Liter
on a 4 stroke engine without much issue (when you build it properly, of
course). Building a 1,000 HP 5 liter engine can be done by buying off the
shelf parts. The problem is that when harmonics start dancing to the devils
fiddle, your valves start to drop, and your pistons shatter like the dreams of
those who bought ENRON stock.

The rotary is my favorite racing engine. It doesn't drop valves (it lacks
them). You can scale them by bolting on _more rotors_ (12 rotor beast here:
[http://i436.photobucket.com/albums/qq83/Adam-
Blackshaw/12rot...](http://i436.photobucket.com/albums/qq83/Adam-
Blackshaw/12rotor2.jpg)). They rev like crazy and feature few moving parts.
But they are hard to tune properly, and tend to run a bit hot if not
maintained correctly. Mazda built, raced, and won Lemans in 1991 with a
4-rotor equipped car called the 787B. Which sort of proves that they are
viable engines. The real problem is emissions. The rotary has not received as
much R&D as the 4-stroke, and thus it is a bit behind. Further developments by
Mazda have improved it, but I don't see it lasting too much with the future
CAFE standards looming over the horizon. It is also not very fuel efficient,
due to it using ports rather than valves. Though I'm curious as to how a
direct injected rotary might improve all of these issues. Not sure if I will
ever see it happen.

Before you call me biased towards the rotary, let me tell you that I do not,
or have ever owned one. I have worked with them, and got to enjoy it very
much. My current favorite engine is the Porsche flat 6, because the damn
things will take any boost you send their way.

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RobLach
I never understood why Wankel engines aren't paired with continuously variable
transmissions so that you can keep the engine at a constant rotational rate.
Many of the issues with Wankels (gas mileage primarily, as well as emissions)
are eliminated when tuned to a specific RPM.

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slurry
The thing to remember about a CVT is that it's held together by a rubber band.
Materials engineering has gotten very good at making stronger rubber bands
that don't snap under hard use, but the application you have in mind sounds
like an awful lot of wear and tear for a rubber band to undergo.

And, if the whole setup is tuned very specifically on the CVT working properly
and the rubber band goes snap, that could be a bad thing.

~~~
AmVess
CVT's in automobiles rely primarily upon metal chains for drive, not rubber
bands.

~~~
bliti
They are sort of metallic rubber bands.

~~~
Gravityloss
There's also these toroidal Centroid continuously variable transmissions. But
they rely on friction and have small contact surfaces.
[http://auto.howstuffworks.com/cvt3.htm](http://auto.howstuffworks.com/cvt3.htm)

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yaddayadda
I love this, as well as the sister-site, 507 Mechanical Movements [1].

I'm surprised at how laborious the process is [2]. Is there not a way to
automate this in a CAD program and export it (e.g. SolidWorks [3]); or is that
limited to video, not a more interactive simulation? Are there any open source
CAD programs that would support generation of such simulations?

[1] [http://507movements.com/](http://507movements.com/)

[2]
[http://www.animatedengines.com/howto.html](http://www.animatedengines.com/howto.html)

[3] [http://www.solidworks.com/sw/products/3d-cad/cad-
animation.h...](http://www.solidworks.com/sw/products/3d-cad/cad-
animation.htm)

~~~
Lerc
I was rather disappointed to see that they were animated gifs. I would much
rather see them in a format where you can run them with independent speeds and
framerates.

I figure it would be better to represent the image as a bunch of shapes with
changing position/rotation. In fact using these animations as a base It might
not be too hard to automate the process to identify the shapes and the
connections between them.

~~~
mxfh
At least on the site liked in the OP they are sprite maps* saved in gif format
not animated gifs.

For example:
[http://www.animatedengines.com/jets.html](http://www.animatedengines.com/jets.html)

The custom player takes the class of the div container
([http://www.animatedengines.com/img/tprop_fl.gif](http://www.animatedengines.com/img/tprop_fl.gif))
"aeplayer aepframes_6" to determine the number of frames (6) and offsets the
background-position vertically for each frame by the amount of the individual
frame height which equals the div container height, thus appearing animated.

*see this example with a sprite map in png format [http://jsfiddle.net/simurai/CGmCe/](http://jsfiddle.net/simurai/CGmCe/)

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kitd
Fantastic. However, it needs the Napier Deltic engine ...

[https://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Na...](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Napier_Deltic_Animation.gif/220px-
Napier_Deltic_Animation.gif)

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calroc
They should include the Tesla Turbine. Only one moving part.

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userbinator
No 2-stroke diesel?

(They make the most awesome sounds, IMHO. Especially the Detroits.)

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Crito
The rocket engine section could be made more interesting by going into engines
with turbopumps and gas generators.

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foxylad
Am I the only one who sees the images slowly floating upwards?

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cfesta9
This is a wonderful education tool. Nice work.

