Have a look at the engine Richard Pearse used in his aircraft

Question: What about either multiple air tanks or a multi-chambered tank with a system to switch from one chamber to the next as a way to keep a more consistent pressure throughout the run. Either a pressure regulated selector or a timed clockwork style of system to achieve the same result. Higher initial pressure would be required to see any real gain though. I think.

ukposts.info/have/v-deo/nnWQgKCIa39zsoU.htmlsi=JYrUbne4WU5eEHE3

integza built one with magnets intead of a ball valve

What about using an *_offset cylinder_* to compare power & efficiency vs a "standard" configuration?

That was pleasant sound indeed

10:1 is a extremely good engine. That's why it sounds so good.

he should make a v12 version and build a wwii fighter with it

Sounds like a diesel under load

Like a revving motorcycle.

This! :)

Couldn’t agree more. I can’t begin to describe my excitement of seeing this video in my feed 😂

For sure. I have loved this entire series. Can't wait until we can see these improvements on a plane or whatever he decides to put them in.

Agree

Yeah! I love the determination to see it through to become a viable motor

Just for the record in the water rocket community its well known that 120 psi is generally where these 2 liter bottles tend to explode. 100 psi is about the upper safe limit you would want to pressurize, 60 psi is almost entirely safe and 80psi is about the upper end of that. Though these are rough figures they should apply about the same. It's also worth noting, its generally not dangerous, just loud, its a little bit of thin plastic, the most it'll manage to do is scare you pretty badly. Unless it sends something flying somehow.

@@killingtimeitself You even try a SodaStream bottle? Not quite as light, but they can handle a LOT more pressure. I've had mine up to 175 psi(12 bar) with no issues... which sort of sucks because I was trying to pop it to scare somebody. I later watched a video from the good folks over at Beyond The Press who had one up around 25 bar(360 psi) before it burst with deformation appearing to occur somewhere near 20 bar(290 psi).

@@dw7444you could always wrap it in packing tape

@@dw7444 i've seen wrapped and reinforced 2l (carbon fiber and kevlar iirc) that can do upwards of a thousand PSI, if you really wanted to maximize thats probably the way, though im sure that increases weight by a minimum of tenfold.

For people that don't like mixed unit conversations: 15bar = 218psi 12bar = 174psi 8.3bar = 120psi 6.9bar = 100psi 5.5bar = 80psi 4.1bar = 60psi And for people that haven't seen the metric light yet, 1bar = 1 atmosphere

In every video it gets more efficient I wonder what the final engine will be

@@ichosolemanuel6048 eventually it will probably just break the law of thermodynamics

By the end of the year he's -invented- established personal flight powered by breathing slightly.

these are not innovations, what he's doing was known 200 years ago and anyone who knows gas laws and understands how a heat engine works wouldn't make his mistakes

@@nirodperAnd that is what makes it fun.

A simpler solution is to have 2 supply tanks, the later (and smaller) at a lower pressure to match the engine. This allows the main tank to be connected via the constant pressure valve. The run tank needs to be large enough to absorb the oscillations. The main tank can then be refilled on a long duty cycle of the supply compressor, starting just before the 2 tanks equalise and stopping at the max SWL of the main tank This system, (called cushioning), is used in high temperature heating systems. It allows the water to be held at a constant high pressure without boiling. The second tank has to be large enough to contain the volume increase of the water due to expansion. When the water is in a sealed loop, a primary tank is not always needed.

A Pratt & Whitney r-4360 wasp

Exactly what I was thinking

But he just told you that the double-cylinder engine is half as efficient as single-cylinder!

​@@Rhannmah MOH POWAH BAYBEE Air powered P47!

@@Rhannmah You can bring facts, science, math to ameritards... but never expect them to accept it.

High quality animations?

I farted

Yeah the whole thing was cgi, I'm glad it's still watchable. Tom def has a good team

@@HaloNeInTheDark27 yeah @ 1:11 @Bctran02 nice

Pumping up you car before going to work 😂😂

@@Guenther-Eichinger Lol!

We? Please explain to the world your contribution.

​@@Guenther-Eichingerinterestingly, that's not as crazy as it sounds. There are actual prototypes for air-powered cars that get similar efficiency to electric vehicles, and would potentially be cheaper and easier to build (not to mention much more encouragement friendly than lithium batteries)... One day you might actually see pneumatic cars on the road 😁

@@ShainAndrews"we" as in the general sense.

Offset crankshaft is a good idea👍

his seal design means there is little to no compression on the upwards stroke, though. exhaust at atmospheric pressure is done by the piston pushing the air down around it's sides and out as it moves upwards.

Agreed on cylinder bore offset - came here to suggest that very idea.

I came here to suggest the offset crankshaft too. They used that trick in the 50s to cheat on car racing.

Isn't that called a desaxe engine?

Wow that's a lot of pressure! I've had one explode within arms reach of my face at just 8.5bar (123psi) and my ear was ringing for 3 days. So that's why I'm cautious now.

@@TomStantonEngineering Was that a PET bottle too or?

@@TomStantonEngineering there are water rocket contests with air tanks going up to 1000psi, using carbon composite tanks. Have you ever thought of something like this? A high pressure engine would really be the next level of engineering.

Huh?

Not really, although CNC Milling a DIY One would be AMAZING *open source mini diesel when*

Maybe after the Kegrocket is ready you could make an air powered Kegdrone 😛

It would allow to find the breaking point of the engines, and possibly make them more reliable and durable at those higher pressures.

@@BasedMan There's a lot to be learned when something fails. Something about, fail in every way possible in each iteration to improve the fastest.

I mean, it would definitely help define the upper boundary of the working pressure

Perhaps a small extra checkvalve? So it opens as soon as there isn’t an excess in pressure

@@xmysef4920 There needs to be an excess in pressure, though. Otherwise the air won't get pushed out. I think the valve needs to controlled by the position of the piston: it needs to open when the piston is at the lowest position up until the piston reaches the highest point.

Maybe a spring loaded valve in the piston head? Valve is open up to ~1.5bar, but closes at higher pressures. Might be hard to do at such small scales.

@@toolscientist cam shaft, my dude. Making it save more energy than it steals is the trick.

The engine already does this, you need to check his earlier videos. The rubber o-ring on the top of the piston deforms to seal the cylinder as the pressure increases on air inlet, and then returns to its original shape as the pressure decreases at the bottom of the stroke, so air can move around the piston as it moves up the cylinder, it isn't sealed during this part of the cycle. There is no compression on the upward stroke. Y'all are coming up with solutions to a problem that this design doesn't have.

Can confirm.

Too bad compressed air already fuels commercial airplanes, but you’re not supposed to know that

​@@ghostwhite1648This is false. You're referencing a meme called the "jet fuel hoax" which purports that jet engines use fuel to start an air compressor which then somehow produces the required power to continue running without fuel. Another variation of this meme says that 90% of the input of the engine is compressed air while only 10% is fuel. In fact this is a misinterpretation of the way that fuel/air mixture works. Combustion of kerosene in air is limited by the Oxygen content of Air, which is 20% O2 and 78% Nitrogen. By volume, only about 10% jet kerosene can be used before all the Oxygen is used up. The combustion heats the air which causes it to expand, which then drives the turbomachinery to compress more fresh air into the engine, this compressed air is then burned with fuel to repeat the cycle. So no, compressed air is not where the energy is coming from, it's where the energy from combustion is converted from chemical energy to heat energy and finally mechanical energy of expansion. Now let me blow your mind! This meme is ALSO a misrepresentation of the work of Viktor Schauberger, the Austrian scientist responsible for early experiments in vortex fluid dynamics. Viktor Schauberger discovered a mechanism to use hot, humid air and a cold sink, usually a cold water tank or body of water like a river, to rapidly compress ambient air to drive a turbine. This is using the opposite process of implosion rather than explosion used in combustion engines. Implosive engines still require a heat difference or humidity difference to operate because only systems that are not in thermodynamic equilibrium can perform mechanical work. The "repulsine" was Viktor's name for this type of cold implosion engine, and he was conscripted by Nazi Germany to construct prototypes for the Nazi war machine. It's unknown how successful this project was, but the principle behind the design is sound, as long as there is a cold reservoir sink available to dump the exhausted, condensed air. Without that temperature difference there is no source of energy to perform the mechanical work of compressing the air.

@@taylorwestmore4664 TLDR a YTer made a compressed air engine. We know the military is 25-100 years ahead of what we are given.

@@taylorwestmore4664 UFOs aren't real still too right? And the water in flint didn't have lead?

Right....much of the physics going on here are well known in the PCP community and surprisingly flat power curves can be achieved with a well tuned gun. It would also be beneficial for the air engine to use a two stage design much like the steam engines on ships where a 'Hi-pressure' cylinder then exhausts into a 'Lo-pressure' cylinder that's sized proportionally to efficiently use the lower input pressure. Steam has a much higher expansion ratio than compressed air so the benefits would be much less....still it seems wasteful to exhaust ANY pressure when the onboard supply is so limited. Entertaining experiments with the air engines Tom!

​@@recoilrob324Or give it an exhaust manifold to get tome scavenging going, essentially create less than atmospheric pressure in the cylinder before the exhaust closes. Very much doable with flexible airhose on the twin cylinder. Might be interesting

Couldn't agree more - Great work Tom.

Yeah if it's dropping the pressure from 60 to 30 then that's half your energy gone. (or maybe only a 3rd. pneumatics is more complicated than hydraulics because it compresses)

​@@charleslambert3368true. I think it goes through adiabatic expansion, so the gas will be slightly cooler at the other side, so it won't quite expand as much as it will lose pressure. So power (= flow x pressure) will be decreased. Unless of course you reheat the gas after it has expanded.

Yes I thought of this exact thing too. He should definitely try that

I think the exhaust is the issue with the engine as you point out, there is a big compression stroke! if the expansion happens and the air in the cylinder is at 1atm at BDC then no air is going to leave the exhaust port, as the piston starts moving up there will be a tiny bit escape before the ports get covered but most of the air gets re-compressed and wastes most of the energy. the exhaust port should be in the piston and opened by the crank shaft, when the piston gets to the top it should close.

@@Hootie811 I think he is avoiding a compression stroke by having seals that don't work without pressure. When the valve opens and high pressure air flows in, the seal is pressed outwards against the cylinder walls. Then when the pressure is released, the seal springs back away from the wall, allowing the air to move past as the cylinder moves back up.

@@robertbackhaus8911 That's a neat design. Its funny how many actual engine concepts he manages to cover (by accident or not) just by developing these. I was wondering if he was going to try and implement some scavenging though I wouldn't see it being effective at all.

I was wondering whether higher engine rpm, from using a shorter stroke/bigger piston and a geared-down prop, would help efficiency. But I'm way over my head in the science!

@@robertbackhaus8911 I have also been thinking and testing of another way of doing this. You use a tilting piston that would seal just a slight bit before the valve opens, and the friction would also be *very* low, since the absolute only contact area that the piston has over the whole cylinder is just the seal, and that contact area is even less when it tilts. You would also reduce the amount of moving parts doing that aswell

See: triple expansion steam engine. All ya gotta do is get the piston diameters matched to the previous stages exit air pressure & the efficiency goes way up.

doule expansion engine when?

Oh man a radial would be awesome!

id also love to see some more common engine designs to be replicated, like an inline 4 (or inline 5 because its cool) or a v6. would be super super cool to hear what it sounds like

@@luukvanoijen7082 inline 5 would be awesome

I wonder is a Radial engine more efficient than a conventional V Engine (If not wrong, Radial engine pretty much not used anymore after WW1, with the usage only being for legacy designs)

Well, a CO2 cartridge is about 800-900 psi. Considering Tom is running 100 psi, that's quite a jump.

I actually dont think it would be so. First of all you usually only puncture a small hole on such a canister, so even though it may very well be 800 PSI internally, the operating pressure of the engine would never effectively reach that unless completely stalled. Also as CO2 is released from such a capsule, it is cooled and the vapor pressure drops. There used to be RC engines that ran on CO2. Of course valve spring etc maybe have to be adjusted, but structurally I think it can handle it no problem depending on what polymer you print with etc.

@@ET_AYY_LMAO Well 800psi in a volume of 14cc, at 100psi it has a volume of 112cc. That's 112ml, Tom is using 2,000L bottles at 100psi. Even at 60psi it's 186ml of volume.

But I suspect, that the gears (especially when home made) that are necessary to combine the two crancshafts of an opposed piston engine will "eat" any additional efficiency. 😲 But it would be good fun. And to push it to the top, why not building a "Deltic" air motor?

YEAH!@@g.j.647

How did you reply 1h ago when the video was posted a minutes ago

Thats a damn good question

​@@Keberal_kanobro broke the fucking matrix, proof that we live in a simulation

@@Keberal_kano Patreons probably get early access to an unlisted video

@@Keberal_kano He probably had early access through Patreon