Forum Chinese Contest

[Mike Everman]

"s-shaped "throat" to maintain the total length limitation"

No no no, Bill; 33" max duct length (as if straightened out). No trombones or u-bends or convolutions to try for more duct length! No telescoping or Tesseracts. ;-)

[hinote]

No no no, Bill; 33" max duct length (as if straightened out).

Got that.

I'll have to work on it. Looks like about 6 months, to make it happen.

BTW can we count on Messr. Eric B. for the next big meet?

You're currently the "mystery-man", to the rest of us "regulars"!!

Practice drinking beer and starting pulsejets before then--you'll need it.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[Eric]

Practice drinking beer and starting pulsejets before then--you'll need it.

Hehehe

Any time or place planned for the meet?

If it is in California I will definately go. I really want to move out there and that might be a good excuse to scout the place out. With any luck I might be living out there before the meet, which would be really nice because I am really really getting sick of this winter crap, at least NE PA winters with that damn fridgid Canadian down draft and lake efect snow.

Mike those rules are absolutely perfect!


Eric

[Mike Everman]

To my mind, it's either at Ed's place in northern Arizona, or Mikhail's in Corvalis OR. I am leaning toward Ed's at the moment; shorter drive for me anyway. You can fly in here and ride with me, Eric, check out CA before or after.

[ed knesl]

OK, how's this for rules:

1. 33" max duct length, favoring Chinese/Thermojet layout, disallowing u-bent linears
2. no limit on intakes
3. no limit on diameter
4. turbines and props ok, not considered part of the length
5. valveless only
6. single CC only
7. bent intakes ok
8. augmentors ok, not considered part of the length

TSFC, max static thrust and ??? categories

Official test at Flaming Farm next summer sometime?

I don't know - everything would be allowed, only length is the limit ?

There is no need to get too exited, since it would be about six months
before enything happens and lot of things may change including all
rules now proposed.

I would still favor some more categories with pretty defined rules and
limits, the same way as any racing and competitions go.
On the top of that should be one unlimited category.

Ed

P.S. How about "Roaring Farm" - we had Burning / Flaming Grapes
already.

[Mike Everman]

Sure we could have more categories, but really, we're talking about maybe 5 people doing this, and I can't even think of number 5.

I think making the "hot length" even on all is going to be most informative. Trying to match Eric for raw out of the box thinking is going to be a challenge!

[hinote]

I attempted to start my M10E "Quadir" chinese pulsejet today.

The result is a failure--but it was certainly an interesting one, for me. It was obvious the proportions were incorrect.

Both Eric B. and Mike E. have commented on this thread that the proportions of this engine were "unconventional".

In the case of the current effort, I'll be going back and trying to establish proportions more in-line with the "classic" Chinese. I hope I can save the project, as an easy to build example.

Here's the v1.2 version of the project--it's in the lower photo; the upper is the first (unsuccessful) version, for comparision.

I was going to try and run it today--but "life got in the way", as usual. I anticipate a first effort tomorrow--and I'll post the results.

Stay tuned.

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[serverlan]

Rules, rules


Its thrust for fuel thats important, not thrust for size.
just go for max specific thrust,
provided you can carry the engine to the comp. meet location ;-)
And remove the chinese limit. Any new valveless (i.e. not lockwood etc)
Then we'll just be back to the old "forum" rules.

[Mike Everman]

Point taken, Don. It wasn't the intent to limit it to chinese style only.

To make it fair to linear motors, the 33 inch limit would apply to the length from tail exit to CC head (that is, where the intake tube meets the CC or meets the CC cone). Recouperators also not considered part of the length.

Several of us applying ourselves to a single hot length will really tell us some things. Really. We could use some focus, and true apples to apples testing with at least one metric made equal.

I'm going to start as soon as I play with my AS-1 some more.

[Eric]

I think making the "hot length" even on all is going to be most informative. Trying to match Eric for raw out of the box thinking is going to be a challenge!

Indeed. Out of the box thinking is good, but sometimes you have to think outside of whatever the hell the box is inside of.

Bill that looks much better, hopefull it runs a lot better for you too. Did you flare the intake more? I really think that is a big thing to do, but you could always just do that after the next run.

Eric

[Mark]

Rules, rules
Its thrust for fuel thats important, not thrust for size.
just go for max specific thrust,
provided you can carry the engine to the comp. meet location ;-)
And remove the chinese limit. Any new valveless (i.e. not lockwood etc)
Then we'll just be back to the old "forum" rules.

And on a related note, it's also the thrust to weight ratio, the streamlineness, the weight of the fuel tank, the cost of the fuel, the construction technique and actual cost to make it, and my personal favorite, I kind of like cubic centimeters, like my midsize SUV that runs on 3 cylinders yet accelerates adequately doing zero to sixty in ~7.2 seconds. It's like having half an engine half of the time. When have you ever seen mileage claimed is actual mileage? I just took a trip to Texas and when they say 24 mpg highway I'd swear they are being modest. I guess jet engines can do the same thing though, the afterburner philosophy.
Mark
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[hinote]

I attempted to start my M10E "Quadir" chinese pulsejet today.

Here's the v1.2 version of the project.

Please see the attached photo.

It shows the fueling arrangement for my test attempt today--to start M10E v1.2.

This effort was unsuccessful--but I think I got pretty close.

The fuel stinger is a length of 1/4-inch brake line tubing with the end pinched closed; 2 holes are drilled into the side of the stinger near the end, with a #58 drill (that's small!). The stinger is clamped to the throat tube with 2 hose clamps.

I got a very strong howling mode, and a low-level resonance in the intake tube. I wasn't able to bring it up to full resonance, but I have the feeling that the stinger depth needs adjustng, to find the "sweet-spot".

I'll take the whole thing as-is, to Mike's on Saturday. 2 (or more!) PJ enthusiasts are going to be necessary to get this cantankerous beasty up and running!

Bill H.
Acoustic Propulsion Concepts

".......some day soon we'll be flying airplanes powered by pulsejets."

[Mike Everman]

I'd try a 3/32 copper feed tube, cut straight. Looking good, though!

[hagent]

I'd try a 3/32 copper feed tube, cut straight. Looking good, though!

Hi Mike,

Where do you find that stuff? I am having a hard time finding even the 1/8 hollow copper tubing.

I would like to come. Have to convince my better half.

Can you send me the time, address ect... ?

Thanks!
HT

[Mike Everman]

Noon till dark, Saturday, 82 Aero Camino, Goleta 93117

Any hobby store and some hardware stores, like mine down the street will have a display with all sizes under 3/8 in aluminum, copper and brass.