I am wondering about the quality of these engines, they look crazy!

Also what is performance compared to using Lego motors?

Check this link out:

http://www.moc-pages.com/folder.php/198856

Check this link out:

http://www.moc-pages...lder.php/198856

How is the performance compared to Lego motors, are there any spec sheets including torque/RPM/mechanical power?

Also do you know why it is designed for 1500 RPM, if it can go much higher? Wouldn't there be higher performance at higher RPM design?

Also how is reliability/maintenance?

Ty

Edited June 16, 20168 yr by TheLegoExpert

How is the performance compared to Lego motors, are there any spec sheets including torque/RPM/mechanical power?

Also do you know why it is designed for 1500 RPM, if it can go much higher? Wouldn't there be higher performance at higher RPM design?

Also how is reliability/maintenance?

Ty

1500 RPM is a remarkable feat anyway. Each cylinder tip must go from full speed to a standstill in a quarter-revolution - 10 milliseconds. This happens in 8 millimetres (total stroke is 16mm). Using basic equations, that means that these parts are undergoing acceleration of 160ms-2 (about 16 Gs) for much of their cycle. If you ran it at say 3000 RPM, acceleration would be 64 Gs. LEGO isn't built for that (unfortunately).

I'm not sure about torque, but at 8 bars (max recommended pressure), each cylinder could exert up to 10kg of force (a quick check shows cylinder bore is 13.2mm). So pretty powerful. The only problem is the amount of air it would need - 200 cylinders worth of air every second.

1500 RPM is a remarkable feat anyway. Each cylinder tip must go from full speed to a standstill in a quarter-revolution - 10 milliseconds. This happens in 8 millimetres (total stroke is 16mm). Using basic equations, that means that these parts are undergoing acceleration of 160ms-2 (about 16 Gs) for much of their cycle. If you ran it at say 3000 RPM, acceleration would be 64 Gs. LEGO isn't built for that (unfortunately).

I'm not sure about torque, but at 8 bars (max recommended pressure), each cylinder could exert up to 10kg of force (a quick check shows cylinder bore is 13.2mm). So pretty powerful. The only problem is the amount of air it would need - 200 cylinders worth of air every second.

How is air delivered to the LPE? Is there a way to increase this measurement?

How is the performance compared to Lego motors, are there any spec sheets including torque/RPM/mechanical power?

Also do you know why it is designed for 1500 RPM, if it can go much higher? Wouldn't there be higher performance at higher RPM design?

Also how is reliability/maintenance?

Ty

GIven that you know the design is for 1500 RPM, I assume you have visited Alex's website? lpepower.com Most of the information you need is there. Here is the information from the inline three that you seen in my creations.

http://www.lpepower.com/products/sys-inline-3-engine

There really is no comparison. The torque is phenomenal and at 1500 RPMs..... well..... 5-10 faster than Lego engines make the mechanical power much higher. I think you will suffer from material error before you max out any of the LPE engines. I have never maxed out the power of my inline 3.... and the highest I have ran it is like maybe 80 psi. Every time i have ran it that high I have damaged elements. The reliability of my little engine is great. I have had mine now for at least 2, maybe three years...... and my latest post

http://www.eurobricks.com/forum/index.php?showtopic=131241&hl=

when I pulled the motor out of my unimog and put it into a dragster it worked just fine (after like a year of no use) I lubricated it ... no problems.

GIven that you know the design is for 1500 RPM, I assume you have visited Alex's website? lpepower.com Most of the information you need is there. Here is the information from the inline three that you seen in my creations.

http://www.lpepower....inline-3-engine

There really is no comparison. The torque is phenomenal and at 1500 RPMs..... well..... 5-10 faster than Lego engines make the mechanical power much higher. I think you will suffer from material error before you max out any of the LPE engines. I have never maxed out the power of my inline 3.... and the highest I have ran it is like maybe 80 psi. Every time i have ran it that high I have damaged elements. The reliability of my little engine is great. I have had mine now for at least 2, maybe three years...... and my latest post

http://www.eurobrick...opic=131241&hl=

when I pulled the motor out of my unimog and put it into a dragster it worked just fine (after like a year of no use) I lubricated it ... no problems.

So is there any point to buy V8, if it is impossible to use all the power of the I3?

Do you know if anyone has measured the torque, I am very curious.

1500 RPM is a remarkable feat anyway. Each cylinder tip must go from full speed to a standstill in a quarter-revolution - 10 milliseconds. This happens in 8 millimetres (total stroke is 16mm). Using basic equations, that means that these parts are undergoing acceleration of 160ms-2 (about 16 Gs) for much of their cycle. If you ran it at say 3000 RPM, acceleration would be 64 Gs. LEGO isn't built for that (unfortunately).

I'm not sure about torque, but at 8 bars (max recommended pressure), each cylinder could exert up to 10kg of force (a quick check shows cylinder bore is 13.2mm). So pretty powerful. The only problem is the amount of air it would need - 200 cylinders worth of air every second.

Great knowledge thanks!!

GIven that you know the design is for 1500 RPM, I assume you have visited Alex's website? lpepower.com Most of the information you need is there. Here is the information from the inline three that you seen in my creations.

http://www.lpepower.com/products/sys-inline-3-engine

There really is no comparison. The torque is phenomenal and at 1500 RPMs..... well..... 5-10 faster than Lego engines make the mechanical power much higher. I think you will suffer from material error before you max out any of the LPE engines. I have never maxed out the power of my inline 3.... and the highest I have ran it is like maybe 80 psi. Every time i have ran it that high I have damaged elements. The reliability of my little engine is great. I have had mine now for at least 2, maybe three years...... and my latest post

http://www.eurobricks.com/forum/index.php?showtopic=131241&hl=

when I pulled the motor out of my unimog and put it into a dragster it worked just fine (after like a year of no use) I lubricated it ... no problems.

only problem i see with lpe they are huge even for big scale mocs. I wonder if they could be more compact even if you loose some minimal performance

I have the V-8. It is a fantastic piece of engineering. I have never done any maintenance on it. I only use it for demonstration and have not tried to actually power anything with it. I am sure it is capable of producing far more power than the strength of the output axle on the crankshaft.

How is air delivered to the LPE? Is there a way to increase this measurement?

I think the most common method is to use a small tank of highly pressurised air, such as those from paintball guns. This gives you limited running time, but avoids using compressors. After all, nothing is 100% efficient, so if you used a compressor, you'd be better off using the motor from the compressor to power your creation directly.

These engines always fascinated me.

I use a shop compressor.

I think the most common method is to use a small tank of highly pressurised air, such as those from paintball guns. This gives you limited running time, but avoids using compressors. After all, nothing is 100% efficient, so if you used a compressor, you'd be better off using the motor from the compressor to power your creation directly.

I use a shop compressor.

What is difference between compressor and pressurized air?

Also. Is there any practical point in using LPE- would you have a more powerful car by using the motor used to turn the engine to power the wheels directly instead?

Edited June 16, 20168 yr by TheLegoExpert

What is difference between compressor and pressurized air?

Also. Is there any practical point in using LPE- would you have a more powerful car by using the motor used to turn the engine to power the wheels directly instead?

With a compressor, the motor that pumps the air is on-board and pumps continuously. With air from a tank, you just have the tank. The latter option is better - since LPEs aren't even close to 100% efficient, you'd always be better off using the compressor motor to drive the car directly. However, LPEs are far more powerful than any reasonable number of LEGO motors - their power is probably in the brushless range...

A (slightly inaccurate) analogy might be a real car with an internal combustion engine. The airtank method basically amounts to a normal car - the fuel is stored in a tank and used by the engine. As for the compressor method, that's more like having a massive motor power an on-board oil-extracting machine and a fractioning column, which generates the fuel used by the engine. Given that cars don't tend to drive around with fractioning columns mounted on-board, stored energy is definitely the better option.

With a compressor, the motor that pumps the air is on-board and pumps continuously. With air from a tank, you just have the tank. The latter option is better - since LPEs aren't even close to 100% efficient, you'd always be better off using the compressor motor to drive the car directly. However, LPEs are far more powerful than any reasonable number of LEGO motors - their power is probably in the brushless range...

A (slightly inaccurate) analogy might be a real car with an internal combustion engine. The airtank method basically amounts to a normal car - the fuel is stored in a tank and used by the engine. As for the compressor method, that's more like having a massive motor power an on-board oil-extracting machine and a fractioning column, which generates the fuel used by the engine. Given that cars don't tend to drive around with fractioning columns mounted on-board, stored energy is definitely the better option.

So how do you refill the air tank? It sounds like the air tank would run out really fast and then the motor wouldn't be able to move.

An LPE requires a large continuous volume of pressurized air. Running it from a LEGO compressor or an air tank is not really feasible except at low speed or a very short period of time. You need a big shop compressor to keep up with it.

So how do you refill the air tank? It sounds like the air tank would run out really fast and then the motor wouldn't be able to move.

That's true. A search shows that a pneumatic cylinder has a total volume of about 7cc. Nicjasno's V8 has a 2-stud stroke, so 3.5cm per stroke. 8 cylinders at 1500 RPM will require 350cc of high-pressure air every second. Most paintball-gun tanks seem to hold approximately 700cc, at 3000psi. So if you run your LPE at 100psi, you'll only get 1 minute's running time from it.

That's true. A search shows that a pneumatic cylinder has a total volume of about 7cc. Nicjasno's V8 has a 2-stud stroke, so 3.5cm per stroke. 8 cylinders at 1500 RPM will require 350cc of high-pressure air every second. Most paintball-gun tanks seem to hold approximately 700cc, at 3000psi. So if you run your LPE at 100psi, you'll only get 1 minute's running time from it.

So if I want to make an RC car w/ LPE which could be controlled remotely (no compressor hanging out attached to the remote, everything is contained in the vehicle), I would need LPE, Lego compressor, and motor to power compressor, correct?

It might seem inefficient to do it this way, but I want to have pneumatic suspension and pnumetic doors, so would it make sense in this case?

So if I want to make an RC car w/ LPE which could be controlled remotely (no compressor hanging out attached to the remote, everything is contained in the vehicle), I would need LPE, Lego compressor, and motor to power compressor, correct?

It might seem inefficient to do it this way, but I want to have pneumatic suspension and pnumetic doors, so would it make sense in this case?

If I were you, I would have separate motors for the drive (if you want speed, either two or four RC motors). Then have a Medium motor with pneumatic pumps for the suspension and doors. To get decent power out of an LPE, you'll need a ridiculously fast compressor. If you wanted to run Nicjasno's LPE at 1500 RPM, calculations in one of my earlier posts show that you need 350cc of air per second, all at high pressure (preferably 100 psi). The best data I've found says that it takes around 160 pumps of the small blue pump to fill an airtank (28cc) to 25psi. This means you'll need 5,000 pumps per second - not feasible. Either you'll need a pump running at 300,000 RPM (not happening - the only thing I've ever gotten to go CLOSE to that speed is an 8-tooth gear while messing with flywheels), or an "army" of several hundred pumps powered by an RC motor. In either case, the pump's internal valve means that you probably won't get above 30 psi or so.

In order to increase efficiency i am planning to make a triple expansion pneumatic engine.

Hi Alex. This sounds very nice. Will the basic engine be made out of non-modified Lego bricks (pneumatics and such)? I am asking because I am a bit of a purist. Sorry about that.

Will you provide instructions or the whole engines?

No instructions. If you want i can go into detail why.

But the engine will be made out of modified cylinders and switches just like the rest of my engines. The trick is in the setup.

An expansion engine passes used air from the first cylinder to the next cylinder, where it expands again, etc. Subsequently each cylinder must be bigger in order to to the same amount of work as the first. This will probably require 2 switches per cylinder and some interesting timing mechanism. I hope the tubing won't be a total nightmare.

7 hours ago, teflon said:

Hi Alex. This sounds very nice. Will the basic engine be made out of non-modified Lego bricks (pneumatics and such)? I am asking because I am a bit of a purist. Sorry about that.

Will you provide instructions or the whole engines?

Im afraid there are things to be purist about and others that are best to not be purist about. LPEs are one of those.  The switches are just too rigid, cylinders holes too narrow, and tubing weak and insufficient.  I have Alex's engine and also one I made non-modified.  There really is a night and day difference.  non-modified engines will keep their torque, just not the speed. 

I should make a video demonstration of them side-by-side......

On 8/9/2017 at 4:20 PM, nicjasno said:

In order to increase efficiency i am planning to make a triple expansion pneumatic engine.

I would love to see that.

Are you still working on it? Or did you quit the project?

I am not. For this i'd need non-lego switches. There is just no way to collect the exhausted air from the cylinders, so i'm unable to devise a system that would make any sense. :(