Hybrid Jet Engine - Update 2.0 

That's great to hear. I think we may be on the way.

@@TechIngredients you are absolutely! I cant get enough of this channels videocontent (exept the smokebombs maybe, ánd i am still waiting for the next video about how good or bad the fluidpumpaction will be with that six enormous neodyniummagnets around that fluidchannel? That was a great idea&making to watch en could only get greater so i can not wait longer to see more of it!)

I am very sure you are! This is indeed one of the last remaining high quality, original content channels and i hungrily wait for each video you put out there.

Agreed, LordSlak.

The smoke bombs were excellent (as well). Variety is the spice of life as they say.

what I really appreciate is the fact that he cools down the information enough to where someone like me with barely any mechanical engineering knowledge can understand it, yet he doesnt dumb it down to the point where youre losing a significant amount of important information

That's good. Even if you decide not to go that route its good that your enthusiasm for the field has increased.

learn it all here and not accrue a bunch of college debt to end up working at a gas station anyway

I have just graduated with a mechanical engineering degree and it's one of the few degrees where most of the things you learn are actually things you do on a daily basis. Definitely worth it in my opinion

Good luck to you.

Thank you! Luckily, we did that exactly. Before adding any fuel, we tested the EDFs by themselves and measured the thrust in the next upcoming video. Stay tuned :)

I'll be staying as tuned as possible! I love your channel. Thanks for sharing all your awesome projects :-)

I still can't believe this is a new channel. You guys are just the best! I truly hope you'll keep the format open and inviting and it the spirit of learning.

Thank you!

Yeah, I'd be interested as well in knowing what/how/who/where Bet plenty of other folks would be interested in such a video as well

Velocity, whether it is in a spiral flow channel or an axial pipe can be converted to pressure when it slows. You are correct that these fans are optimized, but it is for thrust, not velocity. They move too much air and they don't accelerate it enough. Running them beyond spec and two in series helps. The expansion you describe is exactly what is accomplished as the air passes the lip of the cone prior to combustion.

Watching this thread with interest. Basically I am wondering if the back pressure on the EDF's is too high to let them work effectively. Would some type of centrifugal blower be better? Not my area of expertise, though.

These are interesting points, but you are focusing on secondary issues. Turbulence is necessary for the burn process and homogeneous mixing of the fuel with the air will not occur with a gradual laminar flow pattern. It is difficult to maintain a flame front even with the shadow of the cone. This is not simply speculative, we tried it. This engine can operate with a diffuser section as you describe and employ traditional bar shaped flame holders, but any flow resistance in this turbulent region lowers mass flow and thrust, requiring a large burn chamber diameter to reduce the velocity. We found a 30cm diameter tube was required to eliminate this loss. It comes down to practical trade offs.

We tested these fans on the bench to see how effective this non optimized type of blower could be. You are correct that a centrifugal blower would be better, however both types of compressor designs need to operate at very high speed before they begin to be useful. The advantage of the EDF is its availability, compact profile and in the case of these JP Hobby fans, its extremely high power handling capability.

When you see the engine operate in part two of this video, you will see that in fact the burn does occur in a pretty small area within the engine.

Thank you.

To begin, the axial fans are not optimized for compression. They tend to move a lot of air, but do not reach a very high velocity. This is best for electric-only thrust on an RC model. However, at very high settings the velocity becomes significant and potential compression is proportional to the square of the velocity. These particular fans are extremely powerful and each stage in the series arrangement is able to achieve 2 PSI gauge/stage. The higher the compression ratio, the more efficiently thermal energy can be converted into kinetic energy and with a fixed amount of mass, the higher the velocity and hence thrust. These electric motors do not achieve a high compression ratio, its actually quite low as jet engines go, but compression does occur and the thrust does increase. You are correct that we want the exhaust gasses to be as hot as possible. Possible is the operative word, without active cooling we nearly melted our first version of this engine. Some method of bypass cooling is necessary. We may elect to change from water to bleed air from the first fan to simplify the system. We may also convert from a steel flame tube to ceramic one allowing higher temps. My understanding of what is going on is reasonably clear. When you see part two, this may help to highlight the strategies and the principles.

The Combustor design that I referenced runs at substantially lower temps, you may want to look at that. The Ceramic Coating is excellent, the next step is concentric tubes with water between them, which will then be converted to steam, adding lots of "volume OR pressure", and further reducing peak temps. The efficiency gain/loss from the water is around zero. You will need a positive displacement water pump that can easily overcome the internal pressure of the engine, while at the same time providing accurate metering, which should be roughly 50% water, by weight, when using liquid Gasoline/Diesel/Kerosene. The volume of water is related to the BTU content of the fuel. As far as combustion temps, I think I wasn't clear enough. The object is to convert temperature into "volume OR pressure". The fuel is actually creating mostly Super Heated Steam as a byproduct of combustion. Adding water just creates more steam without as much Super-Heat. Yes, that is Steam that is melting that metal tube. When you create Super-Heated Steam you are wasting energy. The excess heat only has one thing to expand to create "volume OR pressure", and that is the nitrogen in the intake air that was NOT part of the combustion process, so all that excessive heat doesn't have any additional materials that can covert that heat into additional "pressure OR volume", that's where the water comes in. Gases increase "pressure OR volume", with additional heat added, at a linear rate. But, water increases in volume 1600 times when it flashes into steam. Unfortunately, there's no free lunch, it takes some serious BTUs to take water from "room temperature" to ABOVE 100 degrees C. But if you really could use some temperature management, you may as well take away some of that heat with water, so that you will add enough BTUs to the water to get it close to flashing into steam, which can then be used as additional material for "expansion OR pressure". Therefore better utilizing the available Super-Heat contained in the combustion steam. "Theoretically", there should be no reason for the exhaust temps to be over ~105 C, if they are, you are just throwing away energy, but actually pulling this off is another story. I designed an engine that comes close to this, but it's for rotational power, not jet propulsion, and, believe it or not, it uses 200 year old steam engine technology to achieve ~80% efficiency. Which brings me back around to the "keeping the heat in the engine" thing, this is simply an efficiency thing. You don't necessarily want the peak exhaust temps to be as high as possible. If you will read-up on the "Stagnation Point Reverse Flow" Combustor you will see that there are other factors involved in the combustion process besides just "peak temps". Certain parts of the combustion process take substantially more TIME to complete, this releases more energy where you want it, rather than blowing flames out of the tail-pipe. If you can see flames, you are wasting energy and loosing power. The higher the compression ratio is, the faster the combustion process will occur, it will be totally complete, way before reaching the tail-pipe, AND, you can either have a smaller combustion chamber, OR, you can burn more fuel. If you are heating the surrounding air to ridiculously high temps, your engine will be inefficient. That energy needs to be going towards making something expand in volume or increase in pressure. You will never have more pressure at the exhaust nozzle than the compressor can create, just more volume. My engine design has a compressor that can create over 400psi @ 500cfm and creates super heated steam at 400psi, which is expanded (and therefore reduced in pressure) in 6 stages. The exhaust is at, or slightly below, atmospheric pressure, and is already mostly water. The remaining steam/water vapor is condensed and recycled back into the engine, the few odd remaining exhaust gases are vented to the atmosphere, which are mostly CO2, which is good for anything that's green. No water is lost or has to be added, the water generated during the combustion process is in excess of the losses to the atmosphere. The unwanted pollutants in the other odd exhaust gases are virtually non existent. You are literally building a Steam Engine, (of sorts), thinking of it in this way may be beneficial to you . . .

Imagine how excited he is! He needs to contain his excitement so he doesn't screw it up with the old get it done itis.

I feel the same....great stuff.

I wouldn't worry about him, He's never done anything half assed and doesn't seem like someone who would even consider it.

Thanks, that's good to hear.

You're welcome!

You're welcome.

Me too!

They're wrong. Sometimes you just have to resort to testing an idea.

Thanks!

Thanks! By the way, we are nearing completion of a compact DIY turbo shaft engine for an up coming video.

Great! I'm not sure about the analogy.

@@TechIngredients Like you're all ready to get some when you get home later, and then you find out. It's not happening. So you've got to look at her all night looking beautiful knowing you can't rip her sexy outfit off later, like you normally would. Same here. You get see all this cool tech you built, but no video of it running. Like I thought I was going to see, when I clicked on the video. Both a big tease. Get it now?

Oh, I got it the first time! Just being compared, even remotely, to a urinary tract infection made me a little "itchy"...if you know what I mean.

@@TechIngredients Lol As long as it didn't make it burn when you went to the restroom. I think you're good. 🤣🤣🤣 Alright. Now stop chatting with all of us, and get to that video please. I can't wait. I love all the design improvements. I hope it all helps. 🙂

Thank you. As we grow we will also be able to expand our production of new content. This takes time and money. We have dozens of projects mapped out and some in the works.

You're welcome and thanks!

Thanks! We will cover a pulse jet in a future video. There will be some modifications to the fuel and air delivery system as well.

I would imagine they use sealed bearings and those need to be cooled as well so whatever lubricant they use doesn't get too thin from overheating.

Doesn't propane dissolve petroleum based lubricants? I guess if the heat of the engine would make the oil grease too thin for it to contain anyway, it wouldn't make a difference. If the bearing can hold onto the grease at a high temp, it is totally capable of also keeping the propane out.

There are plenty of inert synthetic greases such as Krytox which won't wash out.

omg feed fuel into compressor when did this turn into a bomb. I think the title is hybed jet engine yup checked it it reads hybred jet engine

If they fail, go ceramic. Plenty of those in the hobby.

Thank you! I think you'll like it.

Sure!

Wow, Thanks!

Thanks! Renaissance science.

Caught*

Thanks!

Thank you!

You're very welcome, and thank you for your content, especially as I know the work involved and the cost of your equipment!

Thanks! Just hold on a bit longer.

That's interesting. Also, we might eventually replace the water with bleed air from the fans to simplify the design. We'll see.

That is a risk. If that proves to be a problem and we still want to push it, water would be a good alternative.

@@TechIngredients If it works, it's a very good way to kill two birds with one stone, especially the nitrous oxide version you mentioned.

@@TechIngredients Also, I suggest turning down the music during the intro about 3dB, and maybe throwing some light compression on the music track when it's in the background.

Thanks!

Thanks!

Thanks!

JP EDF units are all aircraft aluminum. This will still occur to a degree, but much tougher than plastic. Aluminum is a much better material (especially when used for their intended purpose), because even though a high-quality BLDC motor is over 90% efficient, there are still 5000 watts going through there. At 90% efficiency, that's 500W of pure thermal energy they must dissipate. That's like a space heater on low.

It may in fact be enough to use water. This is less likely to dissolve the oil in the bearings and the large heat of vaporization should compensate for the higher temperature of he vaporization. It is unlikely the motors will operate much below ambient in either case due to the high airflow around the motors.

Thanks!

Thank you. Don't be too sure, although we will have to become more selective as the numbers grow larger.

Not to mention the added joy of that turbine whine :-)

There are only a few diy axial compressors on youtube as creating one is a very complex engineering problem. The biggest hurdle outside of machining/tolerances, is that an axial compressor doesn't scale down well, so to make a benchtop model it's much harder than creating a normal sized version for an aircraft. If you plan on flying it, the rest of the equipment doesn't scale well either. You have to deal with heavy accessories that allow the jet engine to function reliably, and the only way around that is to build it larger.

Thanks! We're not slowing down, but the videos represent a mix of some easier projects and some really complicated ones. Depending what's in the works, we may post more or less often.

You've seen right through me! Maybe he could and maybe he couldn't

Hence "more than 10lbs". They only used a 10lb spring last time.

it's 500W not 5000.

@@nikoladd That may be true, but he said 5000 on the video.

Its probably this one. Max thrust 9.5lb. www.falconhobbysupply.com/jp-hobby-jphedf09006s-high-thrust-90mm-edf-with-6s.html

You're correct. I thought he said 500W. On your initial point making trust out of jet engine is not nearly as linear as EDFs. What's done in this video isn't efficient(as is explained in the first video), but is very cool, thoughtful and educational.

Thanks.

Just hold on for a few more days.

Thank you.

love your content and I believe you aare very knowledgable whenit comes to gas turbine engines but Ithink you may have it wrong with this one they is some compression due to the counter rotating fans eliminating the need for stators there's quite a bit of research regarding counter rotating compressors you may find interesting

Actually, a flow surrounding any airfoil (fan or compressor whatever that has a positive angle of attack) compressed by it. As you may know at the bottom of the airfoil has higher pressure than the other so it acts as a compressor.

@@jwh103 air on the bottom of a an airfoil is at atmospheric pressure it's the air that's at the top that has a lower pressure due to the coanda effect

It could work if it were built like a ramjet, but the fan still may not be powerful enough to make that work.

AgentJayZ, I enjoy your channel very much and have learned quite a lot, very informative. As for the stator only providing compression Im thinking that that it is a matter of relative rotation of turbine to engine housing stator blades. let me try to explain my thought.. Imagine that you made an hypothetical engine that operates a turbine at some rpm clockwise, now consider this engine while it is operating at this rpm you start to spin the entire engine housing counterclockwise increasing the spin up to what was the original rpm of the turbine (ignoring all the impractical issues to do so) . while spinning the housing at the counter clockwise rpm equivalent to the initial turbine you observe the turbine is now stationary relative to an outside observer, but the turbine spin relative to the engine housing is stlll the same. Take it a step further by spinning the housing at 1/2 the original rpm counterclockwise, and now an outside observer would see the turbine rotating at at 1/2 speed clockwise, but the relative rotation of the turbine to the housing is again the same.

Thanks! Industrial vacuum motors with their centrifugal compressors would be superior in design, but their weight and power handling capabilities are just too far out of the useful range.

@@TechIngredients part of me wants to argue that. However, I initially suspected the same issue(s) as well. I trust your opinion to be well thought, and based upon sound reasoning & reliably known theory. Might one assume that the ultimate goal is to have a unit which operates within a power/weight ratio equal to current aircraft standards?

Yes.

If we go to a three stage system we will likely steal a little of the first stage air for combustion chamber cooling.

That's great! You're correct, they are costly in both time and money, but the results and the comments are very gratifying. As this channel grows and it's growing very rapidly, we will be able to invest even more to produce interesting videos.

Thank you.

Thanks! Don't be too sure about that assumption. You'll see some results in part two.

Thank you!

We're building a small turbo shaft engine to run among other things, a generator. We also completed a small two stroke generator that has not yet been covered in a video.