"The Millenium Lance" Project Build

[Irvine.J]

Goodevening gentlemen,
or goodmorning, as its 3:20 am...

Here is my latest project build nearing completion, straight out of Wings 3D. The initial idea, was to have the lance able to move it boom foward or back, also extending the flameholder length thus the being able to operate at it maximum potential at a variety of airspeeds. For this run, we will use the boom in a static position.

The cones were printed with Cone designer, then cut from 1.6mm mild steel, and rolled, which was quite difficult as its pretty thick stuff. The noze cone is Zincalum.

The exit nozzle area is calculated by the inlet area minus the area of the lance. (The lance is what I call the small aerospike. Just a nice name for it.) I will add some small V shaped talons around the lance to increase the slowing impact of the air coming in, but might hold off doing that and testing it as is, I haven't decided yet.

I have 2 inlet cones, one is 4.5 to 5 inch, and one is 4 inch to 5 inch in diameter, initially, i'll start with the 4 to 5.

The gas will be injected at high pressure around the inlet diffuser in 4 places. Possibly even liquid propane if the gas works well on its own. I might even flare the inlet diffueser just a tad too.

If anything, its still a mean looking piece of steel...
Hope you like it.
James (47)

Also, I wanted 4 injector nozzles. I couldn't find a relatively cheap 5 way hose or gas fitting, so I had to come up with my own. I think you'll be impressed with how common, cheap and easy to make this little unit is. Its simply a soda or NO2 bulb I had lying around empty, drilled to fit an in hose and silver soldered for 4 way splitter to this jet.

Not bad for a hand rolled job, I used larry's idea of an old steel pipe, a hammer, and alot of patience.

[Zippiot]

Wow that makes mine look like a piece!

I bet it would run in either direction! Very nice job it looks well built.

Ok guys let the ramjet games begin, first to make a jet that produces 10 pounds of thrust wins!!!

[larry cottrill]

James(47) -

I think it all looks really good!

What kind of fuel nozzles are you going to thread into those holes (or however you plan on doing it)? You need to be sure that the supply point on your little manifold has significantly MORE area than the total area of the nozzles. Of course, there should be no other "tight spot" between the manifold and supply pressure, as well. You MUST have a fairly decent pressure drop through your fuel nozzles, or you will never get uniform distribution out of your manifold. But, you probably know this already.

L Cottrill

[Zippiot]

What is the angle on the cone? Is it different from the intake?

[heada]

Wow! um, Wow!

I would be very interested in seeing how this engine performs. How are you going to give it the required air?

-Aaron

[thecheat]

VERY VERY nice, good work James!

I can't wait to see this work! I'll be waiting!

Oh, Zippiot, You're on! Now just to find some metal... I've got some ideas I might try...

PS: James, what program are you using for those nice 3D models?

[Irvine.J]

Thankyou very much guys, I appreciate your kind words!
Zippiot, the ramjet games! Lol this is going to be exciting, goodluck to all those participating. Winner get a box of chocolates or something??? heheheh.

Zippiot wrote...

What is the angle on the cone? Is it different from the intake?

A little bit, basically the spike is slightly greater angle then the inlet, to cause a bit of pressure on the incoming airstream.

Heada wrote

How are you going to give it the required air?

I've got a nice petrol blower with a modified nose cone. I will cut off alot of the cone and toy with it till i get 100% coverage of the inlet.
Then hope its enough airspeed!

The cheat I design most of my 3D stuff in Wings 3D, its free if you google for it, its a great little program, and I use cone designer from the file list
here http://www.pulse-jets.com/phpbb2/files/ ... er_903.zip
to print out templates.

-Larry,
Attached is a pic of how I was intending to put together the "bulbifold" and my nozzles... I wanted to keep the nozzles injecting into the engine itself quite small so the little bulb fills up and pressure remains constant if you know what I mean. I'm not sure about the bulbs inlet hole though, I was thinking the 6mm open pipe end, or an air hose attachment soldered on like in the pic. What do you think?




http://www.pulse-jets.com/phpbb2/files/ ... er_903.zip[/quote]

[Irvine.J]

I"m about to weld the inlet cone, but can't decide if I want to weld on any flameholder "fingers"... any suggestions, otherwise we will try and run it "As Is". What do you guys think?

[thecheat]

I'd try it without the fingers (turn them so they cut the wind not block it) as it looks like you've got enough blockage with just the cone... (from my "oh so professional" understanding.. :D )

Also, I've got an idea for constant gas feed.... here's the idea, make an airtight chamber in the CONE by welding a plate on the back. It'll be hard, I know, but, just drill some holes in the side of the cone, and poof, you've got your expansion chamber and everything! How to attach the hose to the expansion chamber... uh... that's up to you... maybe you could chop of the tip of the cone and solder it there.


PS: oh, and about the contest... um, how do we measure 10lbs of thrust? is it subtracting the blower? (total thrust) or 10lbs of push in excess of the force required to counter the blower?

[Zippiot]

Lets change it to a thrust to weight ratio of 8:1, that sound ok?

Maybe 5:1 actually cause I doubt we are using the highest quality materials to build these...

I say that the thrust will be measured by the jet only, easy just dont attatch the blower to the movable cart.


Ill make a new thread called the great ramjet challenge, post all pics and results in there as well as your own threads.

[Zippiot]

2 questions:

how do you use the wings 3d...I am well versed in autocad and solidworks but this confuses me...

Can you print to scale from the cone program, all my prints end up being tiny...maybe it thinks I'm telling it to print in millimeters...

[Mike Everman]

Looking great, James! ha ha, nice, mate!

[Irvine.J]

Zippiot, yes you can print to scale, all u have to do is if your adding in your measurements in inches, go to prefrences and convert them to Millimeters. It will automatically change the values. Then simply click print. I had tiny printouts in inches too, and the program is good as it just changes the values, try it you'll see.

Thanks mike, I appreciate the comment :D

[Irvine.J]

Gentlemen, may I have countdown please...

T minus 12 hours and counting...



I have 4 relatively high pressure nozzles, about .2 .3 of mm (hell small) and will increase the size as I go along. Initially if i'm not getting enough gas I'll put the tank on its side. If that doesn't work, i'll take out the fuel lines and make bigger holes. I think its important to keep the gas coming in at high pressure however.

[larry cottrill]

James(47) -

Yes, you should plan on using pressure for any such manifold to work well. I think your plan for the nozzles is sound. Good luck with it!

L Cottrill