Oscillating Vacuum Engine

[Epic Technic]

This is a medium sized vacuum engine, inspired by JJ2's engine. It is double acting, but it must still have a flywheel to overcome the deadpoints and to keep it smooth. As the crankshaft rotates, the cylinder oscillates, when it leans to one side, the air is sucked, causing the piston to move and continuing the cycle. This engine is rather fast, I measured it and it clocked in at over 6600rpm. However I'm not to sure if I should be trusting the app. I also used tape on some parts of the cylinder, but do you think this could be considered cheating?

[Imanol BB]

That is really fast, didn't you broke any piece at that speed?

Edited August 6, 2016 by ImanolBB

[Vectormatic]

As for the RPM measurement, i dont believe it went over 6K6, that just sounds like the wear from unlubricated parts would brake something quite fast.

If you want a more accurate measurement, gear down the output shaft by a LOT (like several worm wheels), two 24 tooth worm wheel combos will reduce by 576:1, giving an output speed of 10-12 rpm, which should be judgeable by eye.

[BusterHaus]

You can try measuring the RPM with a strobe light (there are apps for smartphones and tablets to do this). Just put a piece of tape on the wheel and find the strobe frequency at which the tape appears in the same spot.

[JJ2]

Yours seems to run a little faster then mine, I don't consider using tape as cheating, if you want to get my purest half to suggestion use a 5x11 panel sticker and that will seal it using Lego parts

Edited August 6, 2016 by JJ2

[JM1971]

Never underestimate the power of vacuums, a vacuum cannon can propel a table tennis ball straight though a bat.

Edited August 7, 2016 by JM1971

[nerdsforprez]

Agree with above. Vacuums, air power etc. should not be underestimated. These types of projects (i.e. vacuumed powered machines as well as air-powered) used to plaster the internet. Not so much of a big deal anymore, but others have posted similar numbers. Even much higher with air turbines built out of Lego. Not everyone can be wrong.

[Epic Technic]

That is really fast, didn't you broke any piece at that speed?

It didn't break any pieces but the piston did separate often.

If you want a more accurate measurement, gear down the output shaft by a LOT (like several worm wheels), two 24 tooth worm wheel combos will reduce by 576:1, giving an output speed of 10-12 rpm, which should be judgeable by eye.

I actually don't think that the engine would have enough torque move two sets of worm gears, but thanks for the idea.

You can try measuring the RPM with a strobe light (there are apps for smartphones and tablets to do this). Just put a piece of tape on the wheel and find the strobe frequency at which the tape appears in the same spot.

The app I'm using detects the time it takes to complete a rotation by shortly covering the proximity censor each rotation.

Yours seems to run a little faster then mine

Well your's sure looks better than mine.

Never underestimate the power of vacuums, a vacuum cannon can propel a table tennis ball straight though a bat.

Ohh Mythbusters!