www.pulse-jets.com

...and some of the few actual cones I've made. ha

Gotta have injectors and spark in it for this Saturday's mini-meet with Bill and Hagen.

Here's what the 1d plot (NUDiS) looks like; the closed end is at left, at the end of the animation you see what we mean by the "hammer" hitting the CC.

Mmmmm... nice.

Great animation, too. I've wasted an hour already, playing with it. I glued onto it like a moron. I am soooo obvious...

Mike Everman wrote:...and some of the few actual cones I've made. ha

Gotta have injectors and spark in it for this Saturday's mini-meet with Bill and Hagen.

Oh-boy!!-I get to see this beasty run this weekend.

Mike--care to venture a guess about thrust, and/or TSFC?

I'm only trying to
A: Prove out some of my acoustic analysis tool,
and
B: Trying to beat Ed's 5.6 lb which had the same diameter and length, give or take a bit.

This is the most recent incarnation of the double CC area Chinese that is the same length as the Chinese.

Getting an SFC saturday will be cool.

That is very intersting. Are you trying to reduce the airflow out of the intakes?

Eric

Eric wrote:That is very intersting. Are you trying to reduce the airflow out of the intakes?

Eric

Nope, not as a design criteria, though I can see where inlets pointing at each other might help with that.

I'm more certain about the location and lengths of things than I've ever been before. It's exciting to shuck off the geometry of existing motors and have reasoning behind why I've made it just-so. (right or wrong, haha)

Of interest is the intake opening's contribution to the harmonics of the duct over-all. Different intake lengths move the main duct's transition points interestingly. It's only a few percent, but that can mean 20-30mm.

If it does not produce twice the thrust of a Chinese, that is, it needs to get up to 9 lb or so, then I will be trying a few flamespeed enhancers I have in mind to get things moving along at the clip they should.

I won't do any surgery till I get it running on methanol or white gas first, though.

Well, it ran weakly and was a b**ch to start. You name it, I tried it. I played with too many variables on this one, so it's difficult to say which one it's barfing on!
I feel it may hate the inlets aimed at each other, followed by disgust for my CC back-cone (made in error).

It ran with fuel at the closed end like Leo's, and with brake lines with a bend in them run all the way down to where the intake meets the CC.

I think the first surgery will be replacing intakes for a single (unless I can think of something regarding fuel that I didn't try), and try a bit of angle to that entry as Eric suggests, though it's most likely that it's less important on a single.

Ben wrote:Did you try ye olde "plug one intake and see if it'll run"?

Yes, but it was a red shop rag for plug, and didn't try the gamut of injection options. I kind of picked at it off and on all day.

The angling would definately help, dont give up on the dual intakes.

Do you have a dimensioned drawing I could take a look at?

Eric

Yeah, I am thinking about posting the dimensions.

Very nice Mike
Did you do this one with the TIG or the Henrob?
Dave

Henrob. I'm still not confident with the TIG. Sometimes good welds, sometimes not, usually beyond me why one was good and the other impossible.

Mike

Maybe the meaning of TIG process should be renamed: Testy, Impractical, Gadget.

Not being an experienced TIGer myself I can’t be of much help, other than what I have read and been told. Interestingly enough it still appears to be necessary to thoroughly clean even the brightest of stainless to remove surface corrosion and even fingerprints before welding… I would not have thought so, but an experienced welder swears it is necessary, in addition to back purging and / or using Solar Flux…

Regardless of the method, it is still one nice looking engine. I look forward to hearing more about it.

Dave