HTCPJ2 - New PJ in the world

[hagent]

Well guys and girls,

I am no longer a Virgin !

And Wow what a first time beauty

I feel like a new man.

[hinote]

Well guys and girls,

I am no longer a Virgin !

And Wow what a first time beauty

I feel like a new man.

Hagen:

A HUGE congratulations are in order, IMHO!!

Not only do you have a running pulsejet--you also have an operating original design---and it's an annular, besides!

I'm sure I reflect the congrats and best wishes of everyone on this Forum.

I know how you're feeling--the glow of bringing your own design to fruition.

Again--Congratulations, and a job well-done!

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[hagent]

Thank you!

It was very fun to create something that (when I started) no one to my knowledge had done.

Here are some photos for you all to enjoy.

I will try and get a better movie later on.

Cheers!

[Mike Everman]

Oh yessss, reeessonationnnnnn! Great feeling, isn't it? Ambitious project, too. Now your feet are wet, time to see what's what with it, huh?
You must bring it to Goleta when Bill comes down again- maybe in a couple of weeks, I think, what weekend day is good?

[larry cottrill]

Hagen -

Congratulations, my friend! Very, very nice. Just the way I like them - lots of nifty little bits of innovation here and there, as well as in the overall design plan, of course.

Well done, sir! Welcome to the Roarers Club.

L Cottrill

[hagent]

Oh yessss, reeessonationnnnnn! Great feeling, isn't it? Ambitious project, too. Now your feet are wet, time to see what's what with it, huh?
You must bring it to Goleta when Bill comes down again- maybe in a couple of weeks, I think, what weekend day is good?

Ah YES resonation is a great feeling.

What was even more of a surprise was when I turned the air off. I had to look twice to make sure that it was really off, and low and behold life was good.

By chance do you know what the frequency is?

I tried yesterday to start it with some promising rumblings but I couldn't start it. So today I made a very quick "Air Ring" to inject air more evenly in the intake. I had also shortened the intake tube. So I may just try and start it with the old length and the new air ring to see if it runs better.

There is a little bit of throttle range but not much. I need to get a welding regulator on the propane tank so I can see what pressure I'm using.

It was really fun to make and only three pieces were bought. The spark plug and nut, the white exhaust tube from Home Depot 1.25" dia. (closet close hanging tube - mild steel) and the intake tube which was exhaust tubing. The thicker metal made it practicle to tape 4-40 threads for the 8 screws that hold the exhaust tube in the middle.

I think I am the first person to use Gorilla Glue on a Pulse Jet !

The intake ring would, I think, be to hard to weld to the exhaust tube because of the different thicknesses. The glue held up pretty good for the test but it did get a little toasty and is leaking a bit. I will try and seal it up with JB weld which is good till 600 degrees. That might do it. If not I may just try and weld it.

I did have one neighbour stick his head over the fence and ask me what it was. He was cool about it and no police showed up :)

This weekend is out for me but any weekend after that would be fine - Sat or Sunday.

I have to say thanks to everyone for your help!

Especially Bill, Larry and Mike,

Thanks guys,

:)

[hagent]

Wow, another working coaxial. Excellent job, Hagen.

Any guesses as to how it was performing? Did it seem like it was making thrust? It didn't look like it was getting very warm.

It actually got red hot. My camcorder was picking up the IR waves more and giving a false color. There is thrust. Not sure how much. I have to figure out a way to measure it, and the fuel comsumption.

Thanks

[hagent]

Here is a screen shot which show the red a little bit better.

[hinote]

By chance do you know what the frequency is?

About 143 Hz.

Here's a tip for you PJ enthusiasts:

Download "NCH Tone Generator" (Google for it)--there's a 30-day free trial version.

You can run the sound file (or video) of your running engine, and the tone program--at the same time. A careful ear will tell you when the tones are the same, and the program will tell you the numerical value of the frequency.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[hagent]

By chance do you know what the frequency is?

About 143 Hz.

Here's a tip for you PJ enthusiasts:

Download "NCH Tone Generator" (Google for it)--there's a 30-day free trial version.

You can run the sound file (or video) of your running engine, and the tone program--at the same time. A careful ear will tell you when the tones are the same, and the program will tell you the numerical value of the frequency.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

Thanks Bill thats a great idea. Easier than trying to do math on wave forms.

Hagen

[hagent]

I just had to run it again when I got home today.

Last night I cleared off the burned Gorilla glue and re-sealed it with JB-weld. It held up better but I was surprised when the intake tube got red hot. It did not due that the day before.

I may have accidently shortened the exhaust section. My next attempt will be to lengthen the exhaust and see how hard it is to start.

I also want to make some sort of scale and see how much thrust it's producing.

I think with a little tweaking it's quite promissing, and not that hard to build.

I noticed that it was a bit harder to start. The PJ wanted to be hot before it would sustain. Having hot gases verses cold start - does that mean I need a shorter or longer PJ to compensate for cold starts?

Thanks again to everyone for your help and support!

[Mike Everman]

145 Hz on the first, 158 on the second. I use Realtime Analyzer RAL, it's fab. I think it was $20 shareware after a 30 day trial. It has a tone generator too, but also FFT and o-scope. I love it.

[hagent]

Wow I found a tone generator program on my computer and I came up with 157. That was very close. Amazing.

My Uflow predictions do not match the Hz rate. Not sure what's going on there. I guess I have to play with it and find out. It tends to crash on me a lot though.

Can't wait to show you guys the PJ in person:)

Hagen

[larry cottrill]

I noticed that it was a bit harder to start. The PJ wanted to be hot before it would sustain. Having hot gases verses cold start - does that mean I need a shorter or longer PJ to compensate for cold starts?

Consider that the wave travel is slower when the pipe contents are cooler, and that you are trying to synchronize the main tube wave action with the (more nearly constant temperature) intake section. The fact that it sustains when hot but not cold must mean that a higher frequency "syncs up" better. So, I would think you would want to shorten the pipe a little, to raise the cold frequency.

If you take this too far, I suppose you could theoretically end up with an engine that starts cold but stops running once it heats up! I think, though, that experience tells us that the length is more critical for cold starting than for sustained running. Note also what Bill and Mike have said about how critical the fuel spouting location is - that can also be more exacting for starting than for sustained running, in my opinion.

Any differing opinions out there?

L Cottrill

[pezman]

... I think, though, that experience tells us that the length is more critical for cold starting than for sustained running. Note also what Bill and Mike have said about how critical the fuel spouting location is - that can also be more exacting for starting than for sustained running, in my opinion.

Any differing opinions out there? ...