www.pulse-jets.com

Hola, Joe!

¡Felicidades!

(Congratulaciones, Joe!)

GRIM wrote: The scale reads between 23-24 kg. [snip]
This "thrust rig " is very draggy: takes about 4-5 kg to get the engine and stand to slide whilst not running.
[snip] I make no claims about thrust.

I think the, umm..."excessively conservative" design of your thrust stand makes the claim for you: "Nailed it!"

Un gran logro, y le doy las gracias por sus esfuerzos!

Thanks for the test site data...and I am sorry to read about your singed arm hair: may your wife forgive us both!

Cheers!
M.

Heres a link to a couple of vids,
If you watch the kerosene propane run you will see what I am trying to depict in the photo, entrained air/turbulence as marked by the sand , its not often one is able to observe this,

http://www.mediafire.com/?sharekey=fc19 ... dfa073e68a

Also a photo of the front trunnion mount that I fabricated, heavy yes, but it wont fall off in a hurry,

GRIM wrote: Also a photo of the front trunnion mount that I fabricated: heavy yes, but it wont fall off in a hurry...

That's for sure!

Cheers,
M.

Hello Everybody,

Anyone pulling plans for Thunderchine off of this thread should also check here for an update:

viewtopic.php?f=3&p=62324#p62324

The update [mod kit] provides dimensioned drawings for starting fences that are welded into
the transtion cone. The fences reduce cross-flow between intakes when starting air is applied.

Any questions should be posted to this thread, please.

Cheers,
M.

Hi M,

Isn´t there a risk that the steel plates melts from the heat inside the engine or will they get cooled enough by the incoming air?

Is the 14mm thickness a must or can 10 or 12mm be used as well? The reason I am asking is because I have some 10 and 12 mm sheets at home.

Thanks for the update!

Hello Anders,

Johansson wrote:Isn't there a risk that the steel plates melts from the heat inside the engine?

No worries about melting, mate. And I am not going to waste my time arguing with Larry about this.

Johansson wrote:Is the 14mm thickness a must or can 10 or 12mm be used as well?

Whoa! Not 14 mm thick, but 14 mm high. The fences are 70x14 mm rectangles with clipped edges.
Use the same thickness of steel as used to roll the transition cone. Nothing more or less is required.

Cheers,
M.

milisavljevic wrote:Hello Anders,

Johansson wrote:Isn't there a risk that the steel plates melts from the heat inside the engine?

No worries about melting, mate. And I am not going to waste my time arguing with Larry about this. :(

No need to waste time, argue OR be unhappy. Not only will they be cooled somewhat by the entering air, but it is generally observed that the region immediately surrounding a well-developed transition will get a fair amount of heat sinking from the transition wall.

In the case of the deterioration of metal inside the jet that we showed a few years back, the metal sample was entirely detached from anything that could have provided a reasonable degree of cooling. The sample temperature would have been MUCH higher than any part of the surrounding engine shell. I imagine that a better high temp alloy (e.g. Inconel) would have survived handily.

Yes, I am easily taken in, but not THAT easily.

L Cottrill

Very Nice unit...but quite reminisent of the atttaced pic so NO points for originality.....nuf said.....
go Joe...great build..and M good work....teckies rule........
V

Hello Everybody,

Thanks to Anders, we now have the first article photo of the new starting fences:
I have added an inset sketch showing the correct radial orientation of the fences.
I may change the fence dimensions to a triangular shape by adding a deeper bite
to the trailing edge of the each fence. When I have the sketch, I will post it here.

Cheers,
M.

Done!

milisavljevic wrote:I may change the fence dimensions to a [more] triangular shape.

Revised sketches with dimensions are attached. Unless we run into problems, this be it.

(click to enlarge) (click to enlarge) For additional information / example of installed starting fences, read posts after here:
viewtopic.php?f=3&p=62324#p62324 or copy-paste.

If you have questions, please post them on this thread. Thanks!

Cheers,
M.

Vermin wrote:Very Nice unit...but quite reminisent of the atttaced pic so NO points for originality...

My friend, on that point I have to respectfully disagree. The Vietnamese (I think it is) example appears to be a scale-up (and perhaps, modernization) of the basic Chinese engine. Obviously, none of us has ever been close to this one, but it is certainly an engine of the "classic" high L/D ratio of the Chinese. The twinning of the intakes is probably just a feature of scaling up. I would consider the Thunderchine a true "compact" design, though I doubt that compactness is the Holy Grail for M that it is for me. It has many small differences from earlier folded engines, and as far as I can tell, they are all good ones. As you already know, outwardly obvious similarities can be deceptive.

On valveless engines, sweetness is all in the details.

L Cottrill

Hello Larry,

larry cottrill wrote: The Vietnamese ... example appears to be a scale-up (...) of the basic Chinese engine.

The website where the photograph was first found is Vietnamese; the drone and the pulsejet are Chinese.
The enterprising young master James Irvine was able to "dig up the dirt" on the pulsejet and reports that
it pushes 196 N (44 lbf). Thunderchine's core pulsejet develops 30% more thrust, in a much shorter length.

larry cottrill wrote: I doubt that compactness is the Holy Grail for M that it is for me.

It would be more correct to say that I have many grails. Compactness is certainly one of them. My "quest"
(haha) is to simultaneously optimise all of my "grails" (performance metrics), and these are legion (haha).

Thunderchine's off-forum successor, Thunderhumper, develops the same thrust in a 25% smaller volume.

And for what it's worth, my selecting for twin-intakes was a compromise between volume and practicality.

larry cottrill wrote: On valveless engines, sweetness is all in the details.

Now there is a statement that we can both agree on.

Cheers,
M.

Thunderchine's appetite is
equivalent to 1200 ml/min (petrol) or 3.788403 Gallons per minute

http://www.smartconversion.com/question ... conversion
this website is a great tool to use for volumetric conversions and other conversions of one does not already know the math.

Oh my...

Troy T wrote:Thunderchine's appetite is equivalent to 1200 ml/min (petrol) or 3.788403 Gallons per minute.

1200 ml/min is 0.317 gpm, not 3.78...

In any case, 1200 ml/min is a very rough estimate; there is no use for more than two digits of precision.

M.

Yeah I realized my mistake with the decimal point about ten seconds after I posted it but I was in a hurry and didn't change it. I'm really not that dumb