JAVFE Redux

[Viv]

I suggested it in a magnetohydrodynamic thread in the old forum a long time ago, but you do need to provide a current into the ionised gas stream to generate a magnetic field for the coil to work against.

Faaascinating, but I believe you need to add current to the flow in order to move the fluid through (thrusting against) with current supplied to the primary coil, at least with fluids. I was thinking that for the brief moment of combustion, the gas is ionized and therefore charged, and happens to be moving back and forth while ionized, depending on where you are on the engine, perhaps generating AC in the coil. There was some old stuff about one-shot explosive generators the Russians were using to pump lasers, but I digress. This all deserves a lofty new topic.


Mike

I think I said you need a current in the ionised flow? did I not?

Viv

[Mike Everman]

I think I said you need a current in the ionised flow? did I not?

Ah, so you did. My point is still the same. Gases would need to be ionized to conduct, and applying a current to the flow and the primary would make it accel or decel the gas, like the ones functioning in seawater.
Oh, I see what you mean, it's basic, isn't it; if you run current through the flow and coil, the flow accelerates; if you accelerate the flow, it is a generator. But where, oh queen of all things electric do you take the current out, the coil or the flow electrodes? (I suspect the answer is either one depending on whether you want high or low voltage out, and give power to the other for the same reason?)
And didn't you like the "stern look"? I cracked myself up!
Mike

[Viv]

I think I said you need a current in the ionised flow? did I not?

Ah, so you did. My point is still the same. Gases would need to be ionized to conduct, and applying a current to the flow and the primary would make it accel or decel the gas, like the ones functioning in seawater.
Oh, I see what you mean, it's basic, isn't it; if you run current through the flow and coil, the flow accelerates; if you accelerate the flow, it is a generator. But where, oh queen of all things electric do you take the current out, the coil or the flow electrodes? (I suspect the answer is either one depending on whether you want high or low voltage out, and give power to the other for the same reason?)
And didn't you like the "stern look"? I cracked myself up!
Mike

Stern look! in PDE circles some one has probably based a thesis on it and what the best fuel was:-)

Viv

[Mike Everman]

Stern look! in PDE circles some one has probably based a thesis on it and what the best fuel was:-)

Probably Austrian moonshine, and only a German can make it go off.

[Mike Everman]

Well here it is, I managed with some goal-seeking to get the dimensions to work out, it mimics a 3.6" dia Kentfield over-all dimensions:
L: 33.5
W: 4.5
H: 3.5

combustion chamber:
L: 4.8
W: 4.4
H: 2.3

It will look a little different on the bench as I will be adding some features to allow adjustment of intake area and length, preserving sealing at side plates for experimentation. You should be able to see where this is adjusted on the ejector forms, but once it's all welded up as shown, all adjustments are flat out. I kind of like the through hole, nice little flat in there for spark and fuel to go in, though I think spark would end up further down the CC.

All advice or references are greatly appreciated, especially fuel injection lb/h type and method for a 3.6" equivalent Kentfield would be very timely.

This is pretty all-consuming, I can't wait to start cutting. A couple more number checks, and I'll have the pieces sheared. This friday I get my first welding lesson... (I know, how cute..)

Mike

[Bruno Ogorelec]

Oh yeah, any views on pulsing vs. continous fuel injection?
Mike

Pulsing! oh yea baby pulsing with timed ignition too:-)

Viv

OK, I know you are doing it only to make me mad. I know it. I had a valium before responding. Istill HATE IT HATE IT HATE IT!!!!!

:o)

Bruno

[Mike Everman]

Surely you dont' mean the JAVFE5?? (he said, sniffing, looking out the rain speckled window, a toaster cachunks in the kitchen, his tea sits cold and neglected on the stained vinyl checkerboard table cover in front of him; a dog barks outside...) ;-)

[Viv]

Surely you dont' mean the JAVFE5?? (he said, sniffing, looking out the rain speckled window, a toaster cachunks in the kitchen, his tea sits cold and neglected on the stained vinyl checkerboard table cover in front of him; a dog barks outside...) ;-)

No he just means timed ignition thats all, the poor chap cant stand the idea of any thing more complex on a pulse jet than a heater to melt the rancid yak butter to fuel it:-0

Viv

[Bruno Ogorelec]

Surely you dont' mean the JAVFE5?? (he said, sniffing, looking out the rain speckled window, a toaster cachunks in the kitchen, his tea sits cold and neglected on the stained vinyl checkerboard table cover in front of him; a dog barks outside...) ;-)

Ha-ha-ha.... No. I didn't mean the engine. I meant the idea of timed injection and timed ignition. Viv knows I am ideologically opposed to anything with forced timing in pulsejets and throws such things at me on occasion just to see foam at my mouth.

To me, the idea is as abhorrent as abstention from sex, ban on liquor and burning of books. Pulsejets have their own sophisticated mechanisms of ignition that impose their own timing. Tampering with those mechanisms is like teaching a pig to sing -- it wastes your time and annoys the pig.

Look at the dozens of research papers over half a century and you will often find reference to the effect that some kind of imposed timing "might yield significant advances in performance". Yet, in all that time no one has actually come up with those "significant advances". All the best-performing pulsejets that I know of use continuous injection of fuel and impose ignition on the engine only on startup. Everything else is left to the engine to do on its own, and rightly so.

I can _see_ Viv smirking smugly in his corner, but he's too far for me to throw an ashtray at him.

Bruno

[Mike Everman]

OK, so timing is tabled for now. Welll.... cmments? Accolades? Derision? Stark horror? Wry wit? (oh no, we covered that..)

[Viv]

OK, so timing is tabled for now. Welll.... cmments? Accolades? Derision? Stark horror? Wry wit? (oh no, we covered that..)

Oh the pulse jet! sorry i was focused on a witty repost to Bruno:-)

Viv

[Mike Everman]

Hi, guys.
Thought you might like a 3D, rotatable, zoomable look. Oh, yeah, it weighs in at 12 lb currently, though I'm sure since the walls are flat they may need to get thicker.

It's a large file but you're going to have a lot of fun with it. It's an executable with embedded viewer, so you need no special software. Right click on parts in the assembly tree to the left to make them transparent.

Enjoy!

OOps, 2meg must be too big, I'll e-mail it to anyone that requests it. It's very cool.

[Viv]

Hi, guys.
Thought you might like a 3D, rotatable, zoomable look. Oh, yeah, it weighs in at 12 lb currently, though I'm sure since the walls are flat they may need to get thicker.

It's a large file but you're going to have a lot of fun with it. It's an executable with embedded viewer, so you need no special software. Right click on parts in the assembly tree to the left to make them transparent.

Enjoy!

OOps, 2meg must be too big, I'll e-mail it to anyone that requests it. It's very cool.

cool can I have a copy please, I would have emailed but its not on your profile.

I will get back to you but Tuesdays are a bit busy as I am on a welding course in the evenings and I like to study/practice during the day.

Viv

[Mike Everman]

I fixed the visibility of my e-mail, I'll send it in an hour or so when I get to the office. Oh, yeah, "Melted Yak Butter" LOLOLOLOLOLOLOLOL!

[Bruno Ogorelec]

Oh, yeah, "Melted Yak Butter" LOLOLOLOLOLOLOLOL!

You may laugh but it's not that far from truth. Viv refers to the plan my father and I had, once upon a time, for a publicity stunt.

In my pop's native area, a rural part of my country, in the dark days of Communism, there happened a glut of butter. Someone up un the All-Powerful Politburo got his sums wrong about some subsidy or other and the farmers produced a mountain of butter no one needed or wanted.

At roughly the same time, a local railroad line was recognized as a major loss-maker and closed.

While those momentous events were taking place, my old man and I were talking pulsejets. I was perhaps 15 or 16, My father is a research physicist (now long retired). He used to have his moments. We were talking big V-1-style monsters, built out of oil drums, with valveplates made out of scrap industrial ventilation duct covers (with big, ready-made hinged steel flaps).

Suddenly everything clicked together in our heads and we were planning to mount the big engine onto a rairoad maintenance cart, and having the thing roar along the abandoned track across the Moslavina County, belching fire, powered by -- yes, you guessed it -- melted surplus butter. Killing a great number of birds with one stone, as it were.

OK, so it was a prosaic Hollstein cow butter, rather than the yak variety, but still... I was a horny young man at the time and the thought of thundering along the valley at 100 mph belching fire made me come into my pants repeatedly.

Ah, the follies of youth. I'll never stop regretting the fact that we didn't do it, though we'd probably have ended up in jail. Our brand of Communism was admittedly rather different from all the others, more flexible, and displayed an occasional touch of whimsy, but it would probably have been a bit too much for the Politburo to swallow.

Bruno