"The Millenium Lance" Project Build

[larry cottrill]

That first one must be wrong - 12 amps and only 300 CFM? How can this be? That second one looks good if the specs are correct, but neither one gives us an idea of air speed at the throat. Hmm ...

An impeller would be better, I would think ... like an oversized leaf blower. Of course, they take some power to work well, too!

There is nothing wrong with cones joining cylinders, as long as the "break" in contour isn't too sharp. This is especially true joining onto the front of combustion chamber, as the speed there is supposed to be low.

L Cottrill

[heada]

What about a tear-drop shaped cone? Start off fairly thin, slowly increasing in width (almost logarithmically?) and then coming back around.

Here is a very crude drawing (done freehand...with a bad mouse, in 5 seconds...and I have NO artistic abilities)

-Aaron

[Zippiot]

It is quite difficult to roll a sheetmetal cone shaped like that. You could make a composite cone in that shape but it is still somewhat difficult.

It is the correct idea though.

[heada]

I was thinking that I could turn something like that on my wood lathe made out of styrofoam (closed cell blue foam) and then cover it in carbon fiber. I do similar things for my rockets all the time (boat tails, custom nose cones, etc) Once the carbon fiber is cured, I use acetone to dissolve the foam and I'm left with a very strong but hollow form.

Attaching a hollow cone made from carbon fiber to the ramjet would be a bit of a challenge, but I was thinking of embedding some spars into the foam and then wrapping the carbon fiber around that so I could do a metal to metal attachment.

If I find that this works, I wonder if the space could be used for a small fuel pump and fuel bladder.....bah, thats just crazy talk!

-Aaron

[Zippiot]

At the moment I am making a mold of a cone so I can make carbon fiber copies of it. I plan on using one of them for my ramjet, already figured out how to attatch it and a way of pumping the fuel through it. But my cone isn't really to change the expansion ratios for my jet, more to smoothe the airflow over the fuel injection system. Plus a cf cone sticking out the front looks sweet! Gotta cover the back of it with heat resistant paint so the whole thing doesnt melt...

[Irvine.J]

Check out these beasts...

http://www.spencerturbine.com/blower.ht ... entrifugal
and
http://www.cincinnatifan.com/centrifuga ... lowers.htm
and
http://www.thomasnet.com/
has a big list.

Larry I'll be banging up that cone now, I just woke up, straight to work.

[Irvine.J]

There goes the planet...
No flare as yet, I think the spike will help the incoming airflow pass well out to the side walls, though, I still got my big ball of bluetac here...yippee,
This look ok Larry? Inlet area is much smaller but doesn't seem to causing any issues when I blow into it.

[Irvine.J]

SLow motion...LOL!
Just waiting on my gas nozzles then i can fire this baby up shortly with its new mods.

[Zippiot]

Did you use the zincalium (check spelling) for the newest addition to the intake?

Looking good, I'm startin my metal work tomorrow and should have the jet all wired up and ready to go next week!!

[Irvine.J]

Yep sure did (Zincalum) its only 1 mm thick, easy as pie to weld/bend shape etc. Took me about 4 minutes, I cut most of it with tinsnips then just angle ground off the rest.

[larry cottrill]

Check out these beasts...

Ooooooh ... now you're talking.

I really like those Cincinnati ones called "Pressure Blower" - the little square outlet hole surrounded by a big heavy-duty flange. I'll bet even a 5hp one of those babies would be a wonder to behold!

Yes, some nice ones to choose from! For ramjet testing, you'd favor the ones with large, narrow volutes and small outlets, I think.

L Cottrill

[larry cottrill]

There goes the planet...
No flare as yet, I think the spike will help the incoming airflow pass well out to the side walls, though, I still got my big ball of bluetac here...yippee,
This look ok Larry? Inlet area is much smaller but doesn't seem to causing any issues when I blow into it.

Nice, as usual - you still need a slight flare, though. True, the air next to the spike will be flowing down the cone wall, but the air at the outer edge of the inlet will be impinging straight on! You need that flare to "wrap it around" smoothly, so it doesn't immediately break away from the edge in turbulent eddies.

Nice work, though - looks like a winner to me.

L Cottrill

[Irvine.J]

Here is a picture of how I made my new high pressure injectors, with tiny .4 or something (its hard to tell) drill holes. At max they are .5 mm, but i think they are smaller then that. Anyway here is a picture of how they turned out, most happy!

Also ok larry i'll give it a tiny flare, but I will run it in this mode once or twice first for experimentations sake. In the future I'd suggest we put the quadjector in the actual inlet spike, shooting the gas outwards towards the walls of the cc, it should be pretty easy secure in there, its now 2 am, I can't wait!

I forgot to say in the injector pic to also get a hammer and a small nail and make a small dint where your going to start drilling your hole

[heada]

Check out these beasts...

Ooooooh ... now you're talking.

I really like those Cincinnati ones called "Pressure Blower" - the little square outlet hole surrounded by a big heavy-duty flange. I'll bet even a 5hp one of those babies would be a wonder to behold!

Yes, some nice ones to choose from! For ramjet testing, you'd favor the ones with large, narrow volutes and small outlets, I think.

L Cottrill

What about this one?

http://www.mdhydro.com/inline-centrifugal-fans.html

For $350 (not cheap, I know) you get a fan that can do 1140 CFM and has a variable speed control.

I've found larger (both in physical size and in volume of air) but most of those are industrial (220V 3-phase) and beyond what I can supply.

Just looking for the ideal air source.

-Aaron

[Zippiot]

I think its 550 for the 12 inch fan...

Why not build one? Get an old truck turbo and rig an old ventilation electric motor to it? I bet it would explode but might work for a few mintues...

Why is silicone rtv so expensive? Stupid carbon fiber, pain in my ass