Erics siamese motor

[Irvine.J]

Well, incase some of you didn't know it was Erics birthday recently,
HAPPY BIRTHDAY ERIC!
Anyway, rossco and I have been playing with twin combustors and such things recently, when I remembered that Eric talked about his Siamese for way to long, and decided to build one exactly how he wanted, and keep it as a bit of surprise. Anyway, I think this will be good for a bit of a chin wag so wag you chins!

This is erics Siamese Chinese lol, if that makes any sence, this particular one is two lairds joined by a really nicely sized U bend, not welded yet, but will be run tomorrow.

Happy Birthday Eric, SURPRISE!!!
Hope you like it.

[Mike Everman]

ha ha, that is so bitchin! Happy bday, Eric.
Oh, man I can't wait to see video!

[Jim Berquist]

That's going to be a WILD CAT!

Happy Birth Day Eric.

The little Thermojet you built for me has a few words for you!

" Hi Dad! I am fine, Jim only torchers me some times. He keeps feeding me strange crap! He has a sick sense of food. Gasoline, Naphtha, Propane, Acetone, and junk! One time he even pumped some paraffin, isopropanol mixture into me. He won't do that again. I barffed a two foot ball of blue flames on him. HeHeHe! You should have seen him run. My big sister the chines still sits in the corner of the room all quiet like. I wish she would wake up! Love you dad, Happy birth day."


Good Stuff from you Eric. Jim

This is a Humor thing! I assure you I am not Psychotic, Yet!!!!!!

[Mark]

Another nice looking engine. It would be neat to have a gate in the middle of the U-Bend to fiddle with, just to play with one side on or both running independently of the other and then open the gate.
Happy Gemini jetting in the zodiac of Virgo.
Mark

[Jim Berquist]

Good stuf Mark:

Some kind of wast gate to dirrect flow! It would not have to be much. Just a 1/4 inch washer to dirrect flow. That could ballance the output!



Just my thoughts!

[Irvine.J]

Woot!
Fuel lines getting fitted as we speak, T minus 20 minutes...

[Irvine.J]

I have to finish my coffee....
OMG I have hideous feet

[Irvine.J]

Couldn't for the life of me get it to sustain after 2 fuel lines, 1 or 2 air feeds, 1 or 2 spark plugs, if I blew air down 1 cc, the other would catch, then if I fiddled with the other fuel line it would sound like its locking in... then just get real loud and stop within about .005 seconds. Strangely though with a rossco and just a spark one will catch but it dies within a second... hmm.

If I leave the engine running long enough for the Heat to transfer around the U bend to the other CC, again it sounds very close to locking in, but all of a sudden...woomf, fireball.

So, I mucked around, tried a bunch of stuff, one will run, the other will not, I got lots in store for you little engine...your in sooo much trouble....
Modification in progress.

[jerry marra]

Hello Irving,
beautiful engines!!!!!!!!!

Did you try connecting one CC to another with a 3/8 line,right in the middle?
Bet it would work!

jerry

[Irvine.J]

Hey jerry, No problem man, i'll give it a whirl, soon as morning comes cause I just ran out of Mig wire Doh! Lol. Its 2 am so the hardware store isn't open for a few hours.

I will try that and my new tailpipe mod tomorrow, looking forward to it
Peace.

[leo]

Hi Irvine.

Couldn't for the life of me get it to sustain

I think the only way it will run, is in sync and that will be very hard to do.
If you want to run them out of sync, you will have to make the U bend longer,
About twice as long as one tailpipe, probably longer, because of the very high speed of sound in the U bend, because of the hot gasses in it.
The u bend acts like a closed-closed pipe resonator if the combustors run out of sync.
I like to see it run, it will run the best if the tuning of the U bent and the exhaust pipes are right for each other.

[Irvine.J]

Heya Leo,
Rossco and I extended the U bend way out and in, going out to the length of the engine and etc and so forth. There seems to be a very interesting point where the engine arcs up to a stupidly high frequency then dies. Though it was exciting to get a bit of blast compression action for the half second or less that it lasts, still fun none the less and brought a smile to Rossco's face. I've added a very different tailpipe, things are plodding along slowly but we are enjoying playing with it.

[larry cottrill]

Hey, guys, you should try a couple with a cold path (intake-to-intake) in lieu of the hot path (your U-bend). This can be a pretty short link, made with gaps like the U pipe of an Escopette, but double-ended. Start out with the tail ends well separated. If you can find a length where you actually get them to run alternately, then you can start bringing the tail ends close together for a second feedback path, perhaps even using a little wave reflector as an enhancement. Ha.

I would expect the interconnection to be MUCH shorter than the overall length, since it will be an almost completely cold path with relatively slow wave travel.

L Cottrill

[Anders Troberg]

Hey, guys, you should try a couple with a cold path (intake-to-intake) in lieu of the hot path (your U-bend). This can be a pretty short link, made with gaps like the U pipe of an Escopette, but double-ended.

I've been thinking along those lines as well.

I suspect the trick is to set up the pulsating cycle through the bend instead of through tail/exhaust proportions. In other words, one CC fires, the blast travels through the bend and fires the other CC, repeat. You might even be able to cut the tail short and instead put an augmentor there, as the precise geometry of the tail is no longer part of the work cycle. If you leave a long tail pipe, the bend and the tail pipe will both have a prefered work cycle, which will, most likely, not match.

Doing a double barrel escopette like that will probably make for extremely good aspiration, as the CC can get fresh air from both ends, perhaps allowing a higher work frequency (which would be regulated by the length of the bend).

Other possible benefits:

* It might be possible to start without forced air, as even a fairly mild pop in one CC will probably ignite the other CC, starting the cycle.

* If there are escopette style slits in the bend, it might suck cold, fresh air into the bend behind the hot charge, which will be rammed down the throat of the CC when the other CC fires. Probably not enough to get any compression, but at least a nice shot of turbulent fresh air getting fed into the CC.

[Graham C. Williams]

Leo is correct.
Glad you had a bit of blast compression. I bet Rossco did smile!

Try placing a large blanking plate between the exhaust pipes so that hot gas and strong compression waves cannot pass from one pipe to the other. You may have to do this with the induction pipes as well!

Graham