Now It Can Be Told ... Cyclodyne Revealed

[larry cottrill]

EDIT: Be sure to see the IMPORTANT CLARIFICATION post, below!

Someday you'll all thank me for this. Or, maybe, curse me ...

Tomorrow I will be a mere 62 years old. I am now tired of sitting on a design that will never be hatched (by me), so here it is for all the world to see, laugh at, etc. This is the one-and-only, ill-fated Cyclodyne engine design, as submitted to and rejected by NASA away back in 2001. There are many things wrong with it, which I will gladly and freely discuss with any and all interested parties on this forum. (Not that I wouldn't still like to get back to this someday, but it doesn't seem likely any time soon, so why not let others "enjoy" messing with it?)

To all my friends who signed the Cyclodyne Engine Non-Disclsure Agreement: You are hereby now absolved of any obligation to hold confidentiality. I'm sure this is a great relief to all of you, after being on the edge of your seats about this ever since 2001.

Nevertheless, I would like very much to see someone build an engine based on (NOT identical to) this idea. So, here's my plan:

I will award as a prize to the FIRST builder to get a Cyclodyne-derived engine to self-sustain, regardless of any apparent realized thrust performance, my prototype FWE Lady Guinevere valveless engine. Yeah, I know, it never did run, but it will make somebody a nice souvenir / remembrance (yes, I do plan to live forever, just not around here where you can get hold of me). So if you want a nice conversation piece, just build up your very own Son of Cyclodyne and get it to run unassisted for a minimum of five minutes, and the Lady is yours to keep.

The PDFs are EXACTLY as submitted to NASA, except for some minor redactions of personal contact information. Be sure to read through the text carefully. It does not read like a Clancey novel -- more like a table of logarithms. Of course, many of you have never seen a table of logarithms. Oh well.

Good luck! May the best steel butcher win!

L Cottrill

[ace_fedde]

Larry,

Thanks for sharing!!
Though it’s only june 2nd 16:01h. in the USA, here in Holland it’s already june 3rd 0:01h. Happy birthday!!

Fedde

[Ghrey]

"" Did a working prototype ever get built? ""

I had two thoughts when I saw the anatomy of your engine neither was the above.

One was "oh that's what I invented that fan spray fuel injector for" *

Two was "I am not immediately in love with this design, It MUST be good"


* It started life as a low flow sprinkler head, so adapted would be more technically correct than invented.


Thank you. I for one would start a build tomorrow if I were not broke, busy, and self employed. If I win the lotto you are funded, Ok?

[Ghrey]

Happy birthday.

[larry cottrill]

Larry,
Thanks for sharing!!
Though it’s only june 2nd 16:01h. in the USA, here in Holland it’s already june 3rd 0:01h. Happy birthday!!

Thanks. The way I see it, I am a few hours older than I was yesterday. It's not the years that take their toll, it's the minutes you either use or waste.

L Cottrill

[larry cottrill]

Happy birthday.

Thank you, too.

L Cottrill

[larry cottrill]

IT IS NOT NECESSARY TO INCLUDE THE EMBEDDED RAMJET TO WIN THE PRIZE.

All I am really interested in is for somebody to prove that the basic geometry of tapping into the front end of the chamber for the recycled gas will work. That's the main distinguishing feature that made my design different from all the prior art I had found. My thinking was, why go clear to the rear end to pick up high speed gas for the ejector, when you can set up a second nozzle right up front to accelerate the gas? It gives you a much shorter, less lossy path. And (probably) a lower chance of accidentally having a pulsejet instead of what you want.

The internal ramjet section should ONLY be needed for a large engine capable of high speed operation. For a "miniature" motor (i.e. model propulsion size motor), the transition to ramjet operation would not be achieved anyway, because high enough flight speed is not attainable. So, the internal ramjet can simply be dispensed with. That probably means the whole thing can be slimmed down to some extent.

Remember, though, this is still going to be a low pressure engine. Like a pulsejet, it will be fairly bulky for the power produced (if any - ha).

L Cottrill

[larry cottrill]

"" Did a working prototype ever get built? ""
I had two thoughts when I saw the anatomy of your engine neither was the above.
One was "oh that's what I invented that fan spray fuel injector for" *
Two was "I am not immediately in love with this design, It MUST be good"
. . .
If I win the lotto you are funded, Ok?

OK. You're on ;-)

Here are the parts for the prototype. The maximum diameter tube (combustion chamber) is 4 inches OD. This is mostly 316SS Sanitary Tubing, often called 'dairy tubing' since moving milk around is one of its major uses. It is extremely accurate in size and roundness; smaller sizes are .062 inch wall thickness; larger sizes .065 inch. It is wonderful stuff to see and handle. It is also not cheap.

The recycling cone was professionally fabricated, but I didn't have to pay for it because they made it to fit my drawing (double size) instead of making it to the dimensions that were clearly shown on the drawing. An embarrassment for sure.

Other than the use of the flanges and heavy clamps to hold it together (oh, and the absence of the outer cooling shell), this is exactly the prototype as shown in the first drawing of my SBIR Proposal.

L Cottrill

[ace_fedde]

Mmm, quiet here. Or nobody noticed the disclosure yet or they are all puzzled

Fedde

[larry cottrill]

Here is a PDF of NASA's Debriefing letter. Many of you have seen this already in slightly redacted form on one of my 'Rejected by NASA' pages, but this is the complete version.

Brief synopsis: They didn't much like it.

L Cottrill

[Ghrey]

Pretty accurate synopsis.

But it is also something of a road map forward, in some ways.


I would call it at least partially constructive.


I will be buying tickets

[Ghrey]

Gorgeous parts by the way...

[larry cottrill]

Gorgeous parts by the way...

Yes, the sanitary tubing is beautifully finished, highly accurate material. Even the eccentric cone edges were a virtually perfect fit to the tubes and fittings. Although the material is inherently expensive, the nice part is that cutting fees (at least where I ordered this stuff) were incredibly reasonable -- which means you don't have to buy any wasted stock! You just have to know exactly what you want. As far as I know, this tubing is available in a very limited set of sizes (all OD, like all "tubing"): 3/4-inch, 1-inch, 1.5-inch, 2-inch, 2.5-inch, 3-inch and 4-inch tubing. Lengths up to twenty feet, if I remember correctly.

The pieces are produced such that even custom cutoff ends are perfectly smooth (as if cut off in some kind of big lathe) and they fit together EXACTLY for butt welding. The material is available in Type 304 SS (brush finished) and Type 316 SS (high polish inside and out) -- the two materials can be welded to each other with Type 308 filler rod or wire, if you want to mix them for some reason.

The flanges and clamps shown are what are usually known as Tri-Clover, but that's just a brand name, really. The white gasket rings are TFE based material (NOT guaranteed for really high temps -- I finally decided to use glass fibre matt for gaskets). As you can see, the connection for the removable U-bend is a different type threaded fitting. There are several connection methods available, but they all involve butt welding some kind of fitting onto a tube end.

All you ever wanted to know about Sanitary Tubing. Ha.

L Cottrill

[Ghrey]

We used to use a place called Tube Service. Pretty good folks if I recall correctly. but that was a decade or so ago. all other references seem erased by time...

[Ghrey]

Sprinkler head, fuel sprayer.


.:.

For scale the threads are 5/16-24


ANY NC shop can make them fast and easy. Just adjust the center bore to your delivery pressure/flow requirements. This one is made to CalTrans specks. for irrigation water.

Note: the higher the pressure the finer the mist.