Odd Metal jars

[PyroJoe]

A quick note about testing the large jar, I found it useful to cut the bottom off and bury the bottom in sand. This method allows testing without repeated welding on the bottom section.

Removed 4 inches from the bottom. Cut the top opening to 4" dia., starting to cycle a little better. Slowly the flame pulses deeper and deeper into the jar then dies.

[GRIM]

Here is a simple tool to quickly flare virtually any diameter of thin wall tube ,

It should be more or less self explanatory , you just work it around the pipe like it were one of them old fashioned can openers, and with a little work with a file and some abrasive paper one can produce reasonably good flares

I have flared inlets and tailpipes using various methods , hammer and block , lathe , hydraulic press, but this is by far the fastest and easiest method that I have come across yet

The results are not perfect , but more than adequate for experimenting ,

[Jim Berquist]

Wow too simple!

[PyroJoe]

That's a time saver! Easy on the ears also. My peening hammers are shiny for all the flaring they have done.

[metiz]

that's genius. simplest solution is often the best

[GRIM]

Here is another vid of my small semi oval engine, I have fitted a small transition cone to the CC,
Noteworthy might be that the inlet flame at the beginning is quite well defined , but
as I increase gas pressure and reach max power, the inlet flame gets smaller , (or maybe less visible) and the exhaust flame gets larger,

I have noticed this effect on other engines with this type of inlet .

[GRIM]

Heres a vid , of my mid size draft engine ,

Runs from jam jar to full resonant , doesn’t need compressed air or sparkplug for vertical start , once resonating , it will run horizontal with no problems ,

Could be built with a straight inlet , thus ” no cone engine” , but runs better with the inlet as shown,

Tested with 3 point injector as shown , but will also run with a rosscoe down the inlet other types may work also ,

Will jam jar nicely on methanol and gasoline,

Thrust unknown, but likely not much, and consumes large amounts of gas,
At full throttle expect a 6” flame from inlet 15” flame from exhaust, very loud,

An unregulated gas supply is essential as is ear protection.

This may be a candidate for a “first engine” it is very tolerant to dimensional errors and does not require much in the way of fabricating skills or tools , starts easily with no air or sparks and can be run at very low power levels in a typical back yard without causing too much noise ,

If anybody is interested let me know , I will post some pdf layouts of the ovals etc ,

[Jim Berquist]

Looks cool to me! Sounded a little like a Modle T for a minute there.

[Mark]

(Warning - abstract thought ahead)
That was a fine, gradual transition. If I may say, it reminded me of leaving the dock to go fishing at the crack of dawn, exhausts bubbling in the water at idle and then putt-putting away from the pier, gradually accelerating until the boat is up on a plane, heading out to sea. ha

[PyroJoe]

GRIM,

Definitely post the PDFs. The only problem with this being a "first engine" is that it would spoil the novice and he would expect every engine to start that easy! ha

Joe

[GRIM]

Heres a zip or rar or whatever they are called these days , if anyone has problems let me know and i will post the pdfs seperately,

Also thanks to mark for the abstract thoughts , I have been having them for years just never knew what they were called LOL

[PyroJoe]

A special attribute in the above design is the inlet is placed centered on the larger portion of the CC.

[PyroJoe]

The heat and humidity this weekend was almost intolerable. Thus begins the season when most operations move indoors near A/C. Mostly confined to smaller engines and jars. This big double draft is the final engine of winter and I only have a few mid sized engines scheduled to build over the spring/summer.

The double draft was pieced together over the last month or two as another side project. I was torn whether to add a transition cone to the last big draft engine or to add another tailpipe. So this is the alternate to the transition cone being added. I did need to decrease the intake diameter to be less than the tailpipes.

*This is more of a heat engine than thrust engine

There are some rough spots when throttling up, not sure what that is about, maybe the intakes are disrupting each other. Not sure.

Apologize for the converter logo on the WMVs.

[PyroJoe]

I added a long length of pipe to the scaled Reynst setup. Used a three point injector and found I can make it run in this fashion. The injector is just pointed near the opening, where it can fan against the chamber before entering the opening. The flow is mostly rectified. There is some blowback, but I attribute this to the length of pipe being to long.
It will run with or without the internal cone.
It has a great throttle range, much like GRIMs engine. This is all I will post for now, as it lacks a great deal of adjustment before I can go into much more detail.

Thanks again GRIM for the three point injector design, and thanks in general to the forum for posting great information.

[PyroJoe]

Here is a combination I tested a few weeks ago. I was attempting to reinforce the cycle of one jar from the other. Sprayed in some alcohol in the top and bottom jar then lit the bottom jar with a propane torch.

After a really loud BANG, I was a bit stunned. I remember thinking "what was that about, it almost ripped my ears off". I immediately shelved the combination and decided I should leave it alone for awhile.

The best I could tell the bottom jar pushed most of the air in the pipe up into the top jar (compressing the fuel air mixture in the top jar), then flame must have reached the top jar through the pipe and ignited the compressed mixture.