50 and 75mm Kazoo Test Band, apply here

[Stephen H]

wouldnt the pain get sucked back into the jet ??

[resosys]

wouldnt the pain get sucked back into the jet ??

A tiny bit splattered back onto the tailpipe, but most of it flew away rapidly. It was poured into the exhaust about a foot from the end.

[Mike Everman]

Oh, my beautiful thread is in tatters! ;-p)

[resosys]

Oh, my beautiful thread is in tatters! ;-p)

Crap, sorry. Nothing to see here, back to kazoos and world domination!

[Mike Everman]

No worries, perhaps the performance art crowd might like some small Kazoo noisemakers, or so a little bird suggested to me...

Some clarification was requested by Dave on the stuff I suggested for the 180 bend, and re: whether or not to bend a pulsejet anyway if you are going to go fast, to whit:

Serabend is a brand of "babbitt metal" that melts at 200F. It's like lead. Poured in to the almost finished Kazoo and cooled, it'll make a bendable mandrel that will not allow the tube to crush when bending; so the theory goes, then melted out with a propane torch, or boiling water, for that matter. As to the bend, I think I read that the bend is good for static thrust, but that you can benefit greatly from ram air at speed when the engine is left straight. On the 2" engine, which I'm dreaming of model airplane uses, I'd make a simple rectifier that swings out of the way of the intake at speed, allowing the ram air to hit the intake. I think I mentioned that I'll be "calibrating" my leaf-blower with a buddy's pitot tube airspeed indicator at various distances from the outlet to make a quick open air wind tunnel. As I recall, thrust goes way up, as does the drag, and sfc goes way down with speed; we shall see.

[Graham C. Williams]

Dear mike.
Shane has a point and then we have to add VAT. If it's not a problem It maybe better if I get one made up over here.
As you know I have my version of the spreedsheet, but if you send me the dimensions of the 3in motor I'll make one to that.
Graham.

[Viv]

Dear mike.
Shane has a point and then we have to add VAT. If it's not a problem It maybe better if I get one made up over here.
As you know I have my version of the spreedsheet, but if you send me the dimensions of the 3in motor I'll make one to that.
Graham.

Hey I have an idea! just mark it on the packagine "crushed tube, damaged goods"

No VAT on that:-)

Viv

[Mike Everman]

Dear mike.
Shane has a point and then we have to add VAT. If it's not a problem It maybe better if I get one made up over here.
As you know I have my version of the spreedsheet, but if you send me the dimensions of the 3in motor I'll make one to that.
Graham.

Another sale bites the dust! ;-p
Here's the output for the tubing I found. What is a VAT? And Viv, I like your thinking! "Damaged goods return" LOL

[Rescyou]

VAT=Value Added Tax:

http://www.eurunion.org/legislat/VATweb.htm

[mk]

U-bend production steps:

1. crush a/the pipe (not completely ready)
2. put some sand into the pipe (maybe some welding at the ends, but at least "closed crushing" would be needed, I think)
3. heat the (piece of) pipe in a campfire, with a torch or s.th. else
4. bend the glowing pipe around a model radius
5. cut the end caps and put the sand out of the pipe

It came to my mind, because my gradfather told me that some people bend their own motorcycle exhausts during GDR time, because getting spare parts was a headache those days.

What do you think about this methode?


I'm also interested in your test band, Mike, but I don't know how I should pay for a crushed engine (what's "PayPal"?).
I thought of building a kazoo out of gutter pipe, because it's mostly available with 80mm ID (a bit more than 3" ID).
I'll see after reading more about this topic.

[Bruno Ogorelec]

As to the bend, I think I read that the bend is good for static thrust, but that you can benefit greatly from ram air at speed when the engine is left straight. On the 2" engine, which I'm dreaming of model airplane uses, I'd make a simple rectifier

How about the pleasingly simple one from Messerschmidt? Not very effective at standstill, but its efficiency climbs steeply with forward speed. And, it does not inhibit fresh air intake any.

[Mike Everman]

That's nice Bruno, don't get any thrust from the intake, but it doesn't hurt you at least. I wonder if just velocity head at speed is enough, or is actual ram what I should strive for?
If my throats (in and out) are changeable on the fly, perhaps the motor can be adjusted for minimum forward blast, and change gradually in the presence of higher velocity...

[Bruno Ogorelec]

That's nice Bruno, don't get any thrust from the intake, but it doesn't hurt you at least.

Well, on that count you are badly wrong. Such a half-measure would never have passed muster with Messerschmidt.

It actually does the thrust thing very nicely. It is better still if the deflector and the intake are surrounded by a short cylindrical cowling, like those old radial aircraft engines. But, it works well even without it, as the air stream functions as a kind of cowling. The Coanda effect does the rest. That spike is carefully shaped, of course. I can give you proportions…

[Bruno Ogorelec]

... of course, the thing can also be done in a 2-dimensional form, to suit the flat layout of the Kazoo ...

[Bruno Ogorelec]

And this is what the cowling looks like.