Tomahawk Turbine Introduction- A Kaleidoscope of Combustion Events

Alright, welcome back to Engine Reviews. It has been a while, but let's jump right into it. I've been just busy with other things. Okay, so we're going to talk about Tomahawk Turbine. It is an engine that was featured on Motor Trend, which is partly why we're talking about it, and partly because, hey, this is Engine Reviews, and this is what I do. So this feature in Motor Trend gives it some credibility already. It solves the late spark issue of Omega-1. I've been railing on Omega-1. This is clearly more complicated than Omega-1. But it solves the late spark issue, and that is key for my analysis of why this is important. It has no reciprocating, oscillating, or elliptical mass, just like Omega-1 does. So it's in the correct direction, like Omega-1 was in the correct direction. But it seems to solve the spark issue. It has a great torque arm moment, like Omega-1 does. I think it will work, because it solves the spark issue, the late spark issue, and the choking at high speed issue. It seems to solve that. It does have cons. It does use titanium and tight tolerances. That could be a con for the Omega-1 too, although there's a lot less surface area to machine to those tight tolerances. It's clearly more complicated. Like the Alpha-Auto engine, this is a boost-only engine. It must use boost to make this work. You cannot make a naturally aspirated version. And it's clearly going to be more expensive than Omega-1. Just a quick addressing of some issues here. There's clearly differences in the engine design between what was on MotorTrend and what they have on their website. I'm using both sources, which means the engine does not look the same. But it's the available sources I have to work with here. I guess a few things that are clearly changed post the MotorTrend article. It looks like they revamped their exhaust system. They added in the spark ignition system. They just showed spark plugs in MotorTrend. They didn't show any way of how they're getting the spark there. So that's kind of been fleshed out. They've got this new ring design, which I don't see anywhere in the MotorTrend article. So there's some changes. They don't all look the same. I'm going to be flipping back and forth between some versions, images that I got from MotorTrend and what's on their website. Why should you care? I care because I'm Engine Reviews and I review engines. You should care because they make very bold claims. You ought to know if it's crazy or genius. There's a lot to this engine and more systems of why they might be projecting something so high. I'm not going to get into all of them. Bottom line is this is a very sophisticated engine for controls. It's also very difficult to explain that sophistication. So don't put too much stock into the 69% max VTE. I'm not going to be explaining the systems that they built out that appear to be why they're projecting that. Let's just focus in on the power density. This thing has a crazy number of explosions per rotation which gets to your power density piece. Let's dig in. Like I said, I'm not going to touch all the control systems. I'm just going to explain the basic operating principle. Where does the air come from? Where does the fuel come from? Where are the spark plugs? Why is this solved? The omega 1 geometry issue which is par for the course of why I'm talking about it now. Main torque generation and how it works. I'm just going to briefly touch on the exhaust. I'm not going to go through all the exhaust stuff. And then the firing frequency. Why this has a shot of being insanely power dense. Much more power dense than what we have now. I'm not going to talk about the 5th trick cycle that they have for extra power. I'm not going to talk about jam seals. All these other things that they have for their advanced controls. I'm not going to talk about those. Maybe in another video, but not now. This is from the Motor Trend article. This is the air system. Like I said, you have to understand this is a boosted engine. Which comes to criticism 1 which will be in my description. How is this going to work at low speed? It may not work as well at low speed. You'll have to see when you get enough boost so that you still get your air in. These are match speed superchargers. Which means as this whole hub turns so does this air screw which will direct air into the center bring it to the central hub and then this whole central hub gets pressurized. All they have to do is open an area in this at a certain time, so it's a positional valve so to speak and that will push air in. There's no way drawing vacuum to pull air in from the outside. Fuel. Behind these brackets that look more like branding than functional is the functional fuel rail system. They have 3 injectors per injection site. This will eventually go over your combustion chamber and as this spins it will become exposed you can inject into it and that gets your fuel in. So why 3? Well they are projecting 10,500 RPM I think really fast. About twice as fast as your normal engine and you have less time to inject than a normal engine. Hence the crazy number of injectors per cylinder. Spark plugs. This is all from their website. It's all kind of new so to speak. They did show the spark plugs in the Motor Trend article but they didn't show how they were going to make that work. Just extrapolating a bit from the pictures here. Their coils come down to a center ring. They talk about a spark ring here, so this is probably metal. That connects to metal roller bearings and talks to the connection points to your spark plugs. So they just electrify this whole center ring and then that will travel into the spark. So they've got to all spark at the same time then. You can't necessarily change that at least in the way it's laid out now. So they'll all spark all three cylinders at the same time. So this center one. As it rotates around, so the spark plugs are here that will then become exposed to the combustion chamber as it rotates around and then that will send spark into your combustion chamber. So that's how they're getting the spark in. Oh actually, one more thing I want to use on this slide. So this is some pictures from the website talking about the spark system and the controls and things. But I want to talk about this air piece. So in the air that you pressurize this center chamber how you're actually getting air into the chamber comes from a hole in this ring. So the rest would be blocked off. From here to here it's available. There's kind of a bump out here, it'd be sliding on that. As it goes over that area, that opens it up for air to come in. So the positional valve is here actually on the system that's your spark ring. Okay, why does this solve the Omega-1's problem? Alright, there are two main problems with Omega-1 that I talked about in previous videos. One is it can choke at high speeds because it's a split cycle going through a transfer port. And the second is this spark location. So this is the hot side of the Omega-1 engine. Paraman22 had a video talking about I don't know where he got the knowledge, I didn't see it on the website but they can put their fuel in on the cold side as they kind of close that off and it's going into the transfer port so that's good. Hopefully they can pull this up a couple degrees. But they can't spark until this is closed off. Otherwise your explosion goes backwards into your air intake side. That's a no-go. So they have a geometry limited problem in their engine where they can't spark until way later. So they're well into their expansion they're well into their cylinder expansion their combustion chamber expansion before they can even spark and then ignition comes later. So they're destroying all the compression that they had and they may not catch up with the pressure that will actually that reaction needs to build pressure and push on their little paddle here and they are behind and having a hard time catching up, getting too bad. The Tomahawk TX does not have this problem. So here you've got, let me just follow a cycle so your air comes in here air, fuel compression, ignition expansion so this, take a look here, it seals on both ends and then goes. So you can actually spark this at minimum volume and that is key. Far more complicated than the Omega-1 but it solves that geometry problem and because it's not a split cycle it's going to solve the choking issue too as long as they can get enough air in from their centrifugal superchargers through this center piece they should be able to get that in, right? So the air flow through this positional valve is key to the max RPM and the fact that they can actually close off a chamber compress that chamber and spark at minimum volume that's what solves the issue. Alright, torque generation so once you have this so this is just a little bit after minimum volume this should be sparked, you should have your ignition happening, starting to build pressure what pushes on the walls here is going to get cancelled out, just basically load up the bearings on the satellite rotor what pushes here is going to load up the bearings on the main rotor and then where you're getting your torque is on this paddle so it's torque on a paddle similar to Omega-1 with very good torque arm moment, right? So that is fantastic that lends itself to say the high efficiency projections of Omega-1 this one should have the same thing because it's got fantastic torque arm moment but it doesn't have the fatal laws that Omega-1 has it introduces a couple other things, but it doesn't have that alright, and then here's kind of this was explained in the Motor Trend article as well as this lifts off, you equalize the pressure on this side and that side of the rotor, so now it does nothing again in the sense the geometry is the same, it does nothing what you get though, is you start getting pressure pushing on the satellite rotor, so you get an extra torque response on the satellite rotor the way I understand this, is this is all tied together, does the same thing so you start off getting torque on the central hub, then you get torque on the satellite hub and that leads all to your torque from the engine and each time, you have slight variances in your torque arm, but you're essentially at max torque arm moment all the time which is fantastic for getting to efficiency now I'm going to talk about the exhaust, like I said this is the new exhaust system, it rotates around it comes out here ok, power density, why is this so cool? what I love about the Wankel engine, is it's power density it is not more efficient than a four stroke I grant that, it has the apex seal issues, but it is power dense, better even than a two stroke is, ok that's what I love about it, this engine is power density to the max clearly there's other issues well I shouldn't say clearly there's other issues, there are other design factors on this that make it more complicated to control and things like that, but it is a power density monster here's just a chart that they had on their website kind of talking about one power pulse and comparing so one chamber don't worry about your cylinder count, I mean this is basically multi-cylinder by itself because you've got three things here we're just looking at one chamber so just call one chamber around a revolution that's what this is looking at, one chamber around a revolution the four stroke you actually get one power pulse every other revolution two stroke is every revolution you get one the approximated Wankel is basically a two stroke for firing efficiency and you get six in the Tomahawk TX, why? because this is once around it fires three times and to compare to a four stroke, well this goes every other so that's six times, so that chamber fires six times in the amount of time it takes a four stroke to fire once, ok, that's why this thing is such a beast the top part, this top row is just taking into account the efficiency here I'm not commenting on the efficiency right now, I may dig into that at another time it does have fantastic torque arm moments it also doesn't have seals so can it do that? maybe, I mean they're talking about 10,500 RPM and they got rid of the choking issue, so at high speed I could believe some of this at low speed I have issues because one, how are you even getting your boost are you going to get enough pressure into your central chamber to even make this thing work at low speed it probably needs to have a decent RPM per idle on this thing, and probably a bigger starter motor because you have to have these superchargers working to boost so that's one piece to it, the other is it's close contact, no seals but it solves the choking issue of omega 1 so at high RPM I'm not counting this impossible which says a lot, considering it's it's double it's double the efficiency estimate here they didn't even give themselves credit for double but it would be double of 35% if they could hit 70%, and I think their official is 69% for estimate so that's the frequency here this line here, this middle line is why I'm so excited about this engine and at top speed, now they're just talking about max RPM as far as what limits RPM you have two main limiters your ability to breathe and inject fuel as well and then this overall reciprocating mass and not having your engine fly apart so getting rid of the reciprocating mass removes the limitation of the engine flying apart it doesn't remove the limitation of air, now if they're getting boost here and they're pressurizing the whole thing and then they've got a great valve it's just a positional valve that would be similar to a rotary valve for flow efficiency but they don't have much time to get it in so 10,500 RPM yeah, tentatively buying that so my main thing that I'm zeroing in though is on this line possibly they could get 10,500 RPM now, true turbines are well in excess of that this is tomahawk turbine it doesn't have the reciprocating mass clearly the geometry should be good to 30,000 it's just whether or not you can deliver the air and fuel so their projection says 10,500 RPM that's remained to be seen it doesn't have an immediately obvious flaw it's just going to be can you get all that air in there and the fuel in there in time I want to leave with this last quote this is on their website there was a whole technical assessment done by Jared Semick, he's the founder and CEO of Aeternium Aerospace, they are producing a hydrogen powered plane so not in combustion, they're looking at fuel cells for this but they would be a competing technology to tomahawk turbine and yet this guy still wrote that in his opinion this is worth developing it represents a potential performance improvement that outweighs the potential challenges to design and manufacture you can go to their website TomahawkTurbine.com you can find this whole assessment he has concerns with heat, if I remember right, as well as manufacturability I already talked about this is far more complicated than Omega-1 to manufacture, tight tolerances over large rotors, not going to be cheap but if they get anywhere near what they are claiming that is not going to be an issue for comparison combined cycle gas turbines are I think 63% efficient if they hit above 63% efficiency with this engine and I don't even know if I buy that yet, I'll dig into that more and put that as future videos but if they hit that that will be a revolution in the electricity generation space aerospace in general it doesn't really matter how much this thing costs if it's going into a plane and replacing those giant turbines that cost a few million an engine anyway this thing has me intrigued but not to say there aren't problems the spark plug thing is going to be an issue and I think long lasting spark plugs can go 100,000 miles or so but still tearing the engine apart after 100,000 miles not the best but with these kind of gains I'm not sure anybody is going to care anyway, hope you guys had a great time enjoyed the video and thanks and stay savvy