Hey all!

I've been thinking about a new 'secret' project.

I would like to build a LPE that doenst' need high pressure (max 2 bar) to run smoothly and with a low air consumption

So, I'm not looking for big LPE (like V8, V6 or even V4) with impressive RPMs and a lot of torque. If nessecairy, I will modify the cylinders. But I prefer to use non-modified.

Most video's on Youtube are those 'big blocks' or one cylinder versions which are (mostly) powered by 4-6 bar.

My experience with LPE's is the following:

- More cylinders = smoother running

- Small cylinders = less air consumption than big cylinder (obviously)

- More RPMs = more air consumption

I've build a simple V4 (unmodified, small cylinders), with 'smooth' switches (old, used switches)

It needed approximately a minimum of 3 bar to run smoothly, and it kept running until 1.8 bar (with a lot of coughing). I was even not able to let it run by Lego pumps (with air tank).

After some experiments (with a couple minutes running on 7(!) bar), the switches started to leak. WIth leaking switches, the engine needed about 2 bar minimum to 'run'.

Unfortunaly I forgot to test the RPMs.

Some experimental testing:

https://www.youtube.com/watch?v=qwNF3fB4JfU

There is another technique to control the cylinders, by squeesing the tubes (switchless)

From what I've seen on YT, they need a lot more RPMs to run smoothly. Again, most of those LPEs run on 4-6 bar.

Do you have some idea's how I could build an 'eco-friendly' LPE?

Should it be better to use 1 or 2 modified big cilinders?

I'm scared they will use more air and it won't run smoothly on low pressures.

Tomorrow I will do some tests with a switchless engine, probably with 2 or more small cylinders.

Fresko

I have made some V2 LPEs with the big cylinders that are rather smooth. It takes around 1.5 bar to get it started but it can be brought down to run on even less than 0.5 bar. They didn't use any modified pieces plus They didn't need a flywheel at all. They aren't the most compact but can be used in MOCs. I can make instructions if you want.

A switchless engine would bemore eco-friendly but you would most likely have to use 3rd party pneumatic tubing. Also the small cylinders are very powerful so it might not work.

I forgot to add that conrods help make the LPEs much smoother, but they do take up more space. So if size isn't a limitation then I would definitely add conrods.

I like it! I'm new to the Lego world and didn't know that pneumatic motors even existed. Where can I get more info on them.

that's really cool :)

you should try it in a car and see if it works....if you share a ldraw model of it i'd be happy to test it out :)

Thanks!

Today I builded an LPE, with 2 modified big cilinders. It was based on LPEpower's V8.

It ran much more smoothly and with less vibrations.

Also, I got it running by Lego handpumps.

At cost of this, it is a lot more air-thirsty. In just a few seconds, my airtank (plastic bottle of 1L) has insufficient pressure...

Next thing I'll try is making this LPE less thirsty (with an improved flywheel, with a precise and adjustable valve, a larger airtank, ...).

If it passes the 'tests', I'll see if I could build a LEGO compressor which has a sufficient flowrate to let the LPE run idling. Or at least for a minute (until air tanks are 'empty').

Tomorrow pics!

Fresko

Thanks!

Today I builded an LPE, with 2 modified big cilinders. It was based on LPEpower's V8.

It ran much more smoothly and with less vibrations.

Also, I got it running by Lego handpumps.

At cost of this, it is a lot more air-thirsty. In just a few seconds, my airtank (plastic bottle of 1L) has insufficient pressure...

Next thing I'll try is making this LPE less thirsty (with an improved flywheel, with a precise and adjustable valve, a larger airtank, ...).

If it passes the 'tests', I'll see if I could build a LEGO compressor which has a sufficient flowrate to let the LPE run idling. Or at least for a minute (until air tanks are 'empty').

Tomorrow pics!

Fresko

Have you used conrods? The longer the better.