Hagen's Big PJ

[hagent]

Hello everyone.

I built a monster PJ!

I first have to thanks Eric for sending me his TP180-70 plans. The PJ I built was a scaled up version of that.

If you want the dimensions of this type of PJ then please contact Eric.

If I'm a little incoherent in this email it's because I only got the plans about two weeks ago and have been burning the midnight oil to get it to run today.

I'm too tired to post any more today.

I also have to thank Carlos (a coworker) for all his help in filming this PJ and for his assitance. You can see Carlos for a moment when he trys to put out the fire... a little futile if you ask me.

And my wife who let me have the time to build this!

I don't have any measurements yet. But it is putting out around 76-77 hz.

Cheers,

[Rossco]

Hey Hagen,
Nice n big, real big! Bet that one is a belly thumper.

It doesnt seem to be much more than idle there?
Ive had some experience with Eric's engines, and the original that this was scaled from is just hair raising on full power.
Whipping its tail back and forward on the stand and the like.

You really need to feed it what it wants, dont tease it, looks like it could bite!
If youve got pressure up in your tank (i probably cant comprahend how cold it is there) and it still is taking all the liquid you can give it, i would look at increasing your injection size, or number.

And the big question...
What you got planned for this?
Nobody goes and makes something like that without a motive, do they?
Good one.

Rossco

[Eric]

You really got that built in a hurry. I cant seem to get the video to work on any of my computers / players.

One thing, before you try giving it any more fuel, you absolutely must build a better stand! If that makes a big blast its going to shred that stand and probably end up damaging itself, you definately dont want it to shred and then sustain and keep going!

With the "70" Lb size I have had made some extremely powerful single shot blasts that bend the stand and move the 500+ lb concrete block forward. Put as much triangulation into the stand as possible, because you will need it!

These engines will run on such low throttle that it can be very deceptive, sounds nice and pleasnt and then you crank it up to max and can barely breathe!

Is the intake removeable / adjustable like you were thinking about?

Very cool!

Eric

Rossco I cant wait to see the stuff you have been doing too :D

[hagent]

Just got a few minutes here....

You need Divx codec to play it. It was the only way I could get the file size down.

My motivation for building such a large PJ was because I wanted to do a short documentary on the comparason between today's pulse jet and a turbine. When the film gets edited I'll post it somewhere so you all can find it.

I probably have a restriction somewhere; most likely in the connector that attaches to the tank. I drilled it out as best as I could but there is still a little steel ball in there that I can get past. It has worked well for my other PJs but this one is just a little bit bigger.

[hagent]

Hey Hagen,
Nice n big, real big! Bet that one is a belly thumper.

It doesnt seem to be much more than idle there?
Ive had some experience with Eric's engines, and the original that this was scaled from is just hair raising on full power.
Whipping its tail back and forward on the stand and the like.

You really need to feed it what it wants, dont tease it, looks like it could bite!
If youve got pressure up in your tank (i probably cant comprahend how cold it is there) and it still is taking all the liquid you can give it, i would look at increasing your injection size, or number.

And the big question...
What you got planned for this?
Nobody goes and makes something like that without a motive, do they?
Good one.

Rossco

Hey Roscco,

Nice to hear for you.

This is running a bit more than idle. I did have it sustained for a bit on vapor but the pressure soon dropped below the threshold, and I then had to give her liquid. It was and still is a full tank. We didn't run her very long because of the amount of noise. We had the owners/managers of the property come and have a little talk with us. They were very cool, and said we could come back and start it again. John told us we scared the hell out of his dog. lol

Not sure what I'm going to do with her. I might just try and make a cart for her sometime this year. I will definately take her out a few more times and show off to some friends. The intake comes off so I can adjust the lenghth or change the intake so I can install a different fuel injector.

For my fuel injector I used a coper studout? It has a nice bullet nose on it. I put a number holes in it, and guessed at the placement. I brazed it in place. So I can't move it without changing the length of the intake. My next planed run won't be fore awhile because all my house windows arrived at Home Depot and you know what that means.... But I will have to get thrust measurements next time. Maybe by then ERIC will have his cool injectors for sale again....

I agree that the stand needs some TLC, it was built to a minium because of time, but it actually work well for this power level. The CC has a piece of angel iron welded to it and it's mate is welded to a steel rectangular tube which is welded to the long section. There is a hole that a bolt goes through to join them together, so I can remove the PJ from the stand. The other two supports you see are welded only on one end. One on the CC which is holding the big exhaust cone from gravity, and the other is supporting the U-bend. The U-Bend is also connected to the frame by a steel hose clamp. So for this to fail either both welds would have to give out or the bolt and one weld. It's definately possible under extreme power but not at the one I was running at. I was very careful not to try and get it running with tons of fuel. I didn't want that big bang to happen. I just babied the crap out of it until I realized that the tank knob was wide open.

By the way all the welds on the PJ are done with 308 rod and gas welded!
Thanks Larry for all the tips on gas welding SS.

Just a note; it took me awhile to figure out that if the weld bead is too large that you will have an instant crack form. It usually starts off with a big bang that scares the crap out of you. I kept trying to fix it by adding more metal but it just got worse. I was in dire straights because if I didn't fix the problem in one hour we would have miss our only chance at running it before my deadline. To fix the problem I had to grind down the weld bead and start over and it WORK!!!! I was so happy.

Cheers

[Eric]

The 180 can run a lot lower than most designs, so even if its above the minimum idle, its still probably way below idle on a lot of engines.

When this thing is at full power its not going to be anything to play around with. The vibrations alone can shear welds from metal fatigue in a short time, just please strengthen the stand before you run it on high!

I hope to have my lathe either replaced or have access to another one that I can make parts with sometime soon...

Eric

[Mike Spike]

That's just insane! nice work :P

[hagent]

OK. I guess I can't wait any longer.

I uploaded this film to www.thelot.com but they have not posted it yet. I don't know what the hell is going on. It's been a few weeks. I will upload it again tomorrow, but here it is on google video.

If it ever does get posted on On The Lot I would very much appreciated it if you left feed back.

Enjoy!

http://video.google.com/videoplay?docid ... =hot+steel

[Eric]

Awesome, cant wait to see it running on max throttle!

Eric

[hagent]

Please watch and rate this movie. I would appreciate it very much if you took the time to register so you can rate this documentary.

Some of you guys are in the credits!!!!



Hagen

http://films.thelot.com/films/33242

[Jim Berquist]

That is the largest of large Ive seen....

First You need a better Test Stand.

Second. You Need a bigger Bottle of Propane!

Your Start up sequence should be something like this when your done!

Spark on: Check

Fuel Idle: Check

BOOOOOM: Ignition Confirmed

ETG Temp 1200: Check

Idle until ETG is up to 1500: Check

Ignition off: Check

Engine Self Sustain: Check

Announce : Ladies and Gent's....We will be starting Role Out To Run Way 6 West in a Few minutes:

We Will Depart Tucson International in about 10 minutes. Flight Time To L.A. Airport will be approximately 30 minutes...

Commence role out and Take off: At 20,000 Ft Announce: Ladies and Gent's

We will be Transitioning from P.J. to Ram Operation Moving to 60,000 ft.

You will Experience a slight sensation of Weightlessness as we will follow a Parabolic Path...

At Peak Altitude: Shut down Ram Engines and Start Descent:

Pulse Jets are Relighted, Via Spark on, Compressed air burst, Controlled
flight path is Established and land.

You Just Placed 20 Customers at L.A. X Most happy and Experienced in Semispace Flight........


Just a thought: Wouldn't it be Cool?

Jim

[hagent]

Ya I can't wait to fire it up again.

But my house is in chaos. I replaced every window and I'm not concentrating on the inside. I hope to fire it up in a couple of weeks. By then I'll have re-inforesed the test stand and gotten the restriction out of the connector. I'll just need some wheels so I can test the thrust.

Hope you guys like the documentary.

Mike, Larry did you guys see it?

Thanks Jim,

[Eric]

Do you have any other footage of the engine that you could post here, I really cant wait to see that beast on higher than idle.

Definately reinforce the test stand and make it so that the tail cant bounce, look like it was really bouncing like crazy in the video when you turned the throttle up. Definately dont want to form any stress fractures from work hardening.

I am really a big fan of integrated support brackets that allow the engine to expand but keep everything rigid in the other directions.

Eric

[larry cottrill]

Yes, I watched it - highly impressive!

In my opinion, the best mounting will be a true (i.e. hinged) truss - the engine would form the upper leg between two mount points, and any degree of expansion could be tolerated with zero bending stress communicated to the lower bearing points. Nothing beats a truss for strength and lightness, and all the forces can be easily calculated (if you have a conservative value for the thrust force and a good value for engine weight). In a true truss, there are no bending moments, and the tension and compression forces are simply vector distributions of the applied forces, based on the applied forces (vectors).

Of course, the complete mounting would really be two identical trusses, one on each side of the engine, symmetrical around the centerline.

L Cottrill

[hagent]

Hello everyone,

Thanks for all your support.

I was able to get that restriction cleared in the connector right at the propane tank. There was a steel ball around 3/16" in diameter that was causing all of my problems. I hope that the tank does not have any ristrictions internal. In a few weeks I'll be able to test it again.

Eric, your lucky living out in the woods, no neighbours.... I enviy you. Although I think hunting has decreased dramaticly in your neck of the woods. :) I got your DVD and CD thanks!