"Thunderchine" 55 lb thrust pulsejet plans

[milisavljevic]

Assez. Je suis d'accord!

M.

[GRIM]

Taking shape ,

I might as well come clean , I screwed up the big cone , forgot to put the end angle on it, my fault , stubborn , plotted the cones "my way" , later I printed and taped the pdf together, THE PDF IS GOOD , I used the pdf for the inlets and couplers,

I really dont want to make another big cone, Would it be acceptable to make "this one" a concentric in line tailpipe ? same dims just wIthout the angled cone,

One other not to drawing detail, is the thickness of the material , I purchased 1.5 mm , when I got it home and started rolling, I measured it and found it to be 1.8 mm thick , tough stuff , but nice to weld,

No kill Bill , but Jackie Brown might put in an appearance sometime,

G

[Ghrey]

Was I, some how unclear?

[milisavljevic]

And now from left field...
What is the maximum allowable radius for each joint?
Picture the jet made from a contiguous piece of material if that helps.

Was I some how unclear?

Not at all; we were simply ignoring you. While I am as big a fan as anyone of möbius strips,
what you are proposing falls into the category of "unsupported builds". We will not help you.

Make an effort to build to spec., and we will be there for you. If you cannot be bothered to
follow the spec., then we will not. A lot of effort went into preparing these plans: use them.

M.

PS: I just found out that I can adblock your sig. Hallelujah!

[milisavljevic]

Hello Joe --

Rossco wanted to reply here, but me thinks he needs to chill for a while longer. Maybe a day, or two.

( I needed a few hours myself... )

I might as well come clean, I screwed up the big cone, forgot to put the end angle on it,
my fault, stubborn, plotted the cones "my way"...

And I had such high hopes for you; ...all the cones in Thunderchine save two are eccentric cones.
We have to ask ourselves why we even bothered to draw the patterns if no one is going to use them.

THE PDF IS GOOD

You saved yourself here, mate! I wish I could have you stay after class and write that out 100 times!

( It's time to make a decision... )

I really dont want to make another big cone...

LOL. Well... The answer to this question will decide my answer: have you already rolled the ejectors?

If "no", then my answer is "yes": you may use the concentric super cone.
If "yes", then my answer is "no": you must make a new spec. super cone.

If you want to use the cone that you have, then kiss the ejectors goodbye: the whole point of Rossco
having laid out the plans in the present order, was to ensure that they could be mounted and aligned.

So, build and test the pulsejet core, sans ejectors, or roll a new super cone. We don't have the time
to help you suss out how to get the ejectors onto a concentric cone and align them to the intakes, if
it's even possible (probably not). Better to do it right or stick with an unadorned core for testing out.

One other not to drawing detail, is the thickness of the material, I purchased 1.5 mm,
when I got it home and started rolling, I measured it and found it to be 1.8 mm thick.

Wow. The templates were sized for 0.8 mm, so you're way out there. Rossco will check to see where
that puts you wrt. internal diameters, and then I will model how this affects peformance. No worries!

( You just had to do it your way! )

Your photos look good! Please try to stay with the spec. from here on out. I have my fingers crossed!

Cheers!
M.

No kill Bill , but Jackie Brown might put in an appearance sometime.

Have yet to see this one! IMDB rated it 7.6/10. The link... http://www.imdb.com/title/tt0119396/ .

[Ghrey]

It was a tolerances question.

You have in fact supported me.

Thank you for your response.


Explanation: The build would NOT have been in metal, But your response indicates zero tolerance at the joints, and my build method will not support right angle joints, or rather safely support them.

Thanks again.

[GRIM]

Hi M and Rossco,

Rossco wanted to reply here, but me thinks he needs to chill for a while longer. Maybe a day, or two.

( I needed a few hours myself... )

Apologies, to both of you , The main reason for my folly was an ignorance on my part re, PDF ,
I had never previously printed anything to scale using pdf , and I had the "brilliant idea" that the Print shop that I use could print everything and anything on their 900mm wide plotter, this aparently is not possible, also A4 is not an available paper size here , so I chose to go the autocad route ,

Later , I learned that the pdf printer can be configured to plot accurately to any of the default paper sizes which I did, (legal size paper) and indeed the prints come out come out just fine with little alignment/cut marks ,

And I had such high hopes for you; ...all the cones in Thunderchine save two are eccentric cones.
We have to ask ourselves why we even bothered to draw the patterns if no one is going to use them.

Yes I can see that now ,

If "no", then my answer is "yes": you may use the concentric super cone.
If "yes", then my answer is "no": you must make a new spec. super cone.

NO I have not cut or rolled the ejectors , So I guess it will be a concentric "unadorned core" ,

Wow. The templates were sized for 0.8 mm, so you're way out there. Rossco will check to see where
that puts you wrt. internal diameters, and then I will model how this affects peformance. No worries!

No worries there , I took into account the material thickness , the cones are all within spec WRT length / inside diameter

Apologies again ,


Will keep you informed, But progress will likely be slower , my wife returned home last night , and I should really make some progress on the utility room that I was suposedly building this week , whilst she was away ,

G

[milisavljevic]

Hello Joe --

No need to apologise: all of the electrical fires were safely extinguished here and in the land down under.

NO I have not cut or rolled the ejectors, So I guess it will be a concentric "unadorned core".

That's cool. And at least you can get thrust readings independent of the ejectors. Obviously, it does not
matter to the pulsejet whether its tail cones are eccentric or concentric for low-to-moderate half-angles.

No worries there, I took into account the material thickness, the cones are all within spec...

Cool!

But progress will likely be slower, my wife returned home last night...

Oh noes! Say it ain't so, Joe! ...the real world strikes again!

Cheers,
M.

[Viv]

M.

PS: I just found out that I can adblock your sig. Hallelujah!

Poor Genius! Safari Blockflash works too

Viv

[milisavljevic]

Poor Genius! Safari Blockflash works too.

Thanks for the tip, Viv! ...Oops! Another annoying sig bites the etheric dust.

Cheers,
M.

[GRIM]

Hi all ,
A quick question re , plug location ,
the drawing shows the plug location as being close to the throat , "in the metal" this looks like it may be awfully close to a critical zone , any thoughts on re-locating it closer to the outer edge ? see pic,
G

[milisavljevic]

Hello Joe --

The location as specified in the plans is fine, and should cause no problems. This assumes
that the spark plug you use does not extend an unusual distance inside the transition cone.

For example, as shown in your drawing, the plug is almost completely immersed within the
turbulent boundary layer, and thus of no measurable impact to the system. However, it will
work just as well if you want to relocate it closer to the combustor/transition join. A lower
"profile" was the intended effect, but this does not matter if you are building a static core.

Hope this helps!

Cheers,
M.

[Mike Everman]

*I'll be cleaning up this thread occasionally so Q&A is easy to go through. (so toilets will only last so long...) ha

[GRIM]

Storms coming,

[metiz]

The "toilet post" was not meant personal. It was just a little joke towards M for "bitching" about GRIM's build, who's build was (is) freaking awesome except for a tiny mistake earlier on.

On a different note, M, yes, I realy do want to know why your tail is all cone. My understanding is that with a straight section, you get a higher mass flow speed and therefore a higher exhaust velocity. the temperature in the tube will also be higher increasing the speed more so. Discuss.

Also, GRIM......like, TOTALLY AWESOME DUDE