www.pulse-jets.com

I was at a NAPA auto parts store yesterday picking up my Autolite 3095 half inch spark plugs and saw the neatest little aerosol can, no more than 2.5 inches tall without the cap and the same wide.
I like those very small WD-40 aerosol cans too. Remember Larry, they still seem to be having that contest for finding new uses for WD-40 on their website. Maybe if you made a pulsejet out of one of their cans, you could get some notoriety on a lark.
Mark

Mark -

So what was it a little can OF?

That sounds like exactly what I'd like to have for my next Reynstodyne design, the "Black Princess".

L Cottrill

It was some kind of odd lubricant spray, not for belts or just your ordinary stuff, it was for some unique part of the car's engine or brakes, I can't remember what, but I can stop in there again and find out for you.
Mark

On a Fo Mi Chin sidenote, you should've got an email from me about the poster Larry! Sorry for the off-topic post, hehe...

I wonder if it would run on WD-40. Many an hour of my youth was spent igniting things with WD-40. I learned a lot about flame fronts, pressure, etc from those experiments.

And yes, I still have all my fingers and both eyes...

The old tailpipe and intake are removed, and the opening has been cut out for the new intake to fit in. To do it, I just melted it back to the approximate shape with a small torch flame, leaving a nice beaded edge to weld to rather than a thin 'sheet metal' edge. This worked quite nicely, and needed just a few minutes polishing up with round and half-round files to get a perfect fit between the chamber and the new tailpipe assembly. So, it's ready for the final structural weld and then attachment of the not-yet-built fuel / air tube.

Pictures in a couple of days.

L Cottrill

The Fo Mi Chin II is now complete. No engine mounts, as already mentioned. Final weight with starting air tube and CM-6 plug: 15.3 ounces.

For some reason, it is one inch longer than shown in the plans; probably, I mis-measured when I cut the pipe. I don't feel like cutting it back an inch and re-doing the flare, so I'll just leave it that way for now. That only moves the Reynst Point 1/8 inch from where it should be - I can't build it much closer than that, anyway, so it should be fine.

Mike E - I just need to find the perfect mailing tube for it, and should be able to get it out to you next week. Don't touch it, though - remember, I promised Bruno the first chance at this one! If it won't sustain, we'll just blame that extra inch!!!

Final construction photos in a couple of days ...

L Cottrill

Larry Cottrill wrote: If it won't sustain, we'll just blame that extra inch!!!
L Cottrill

No, if it doesn't sustain, you can blame Bruno's technique! Though, with this crew, we'll be able to make a Trombone sustain, eventually. ;-)

Mike Everman wrote:

Larry Cottrill wrote: If it won't sustain, we'll just blame that extra inch!!!
L Cottrill

No, if it doesn't sustain, you can blame Bruno's technique! Though, with this crew, we'll be able to make a Trombone sustain, eventually. ;-)

No man has complained about an extra inch before, and I am not about to do it either. No, if the thing refuses to work, I accept the blame ahead of the time. It will be due to my all-too-long absence from fire and noise, or to the stage fright or something of similar nature.

Larry, thank you again for this wonderful opportunity to try to make the history books. I'll take good care of your baby.

Bruno Ogorelec wrote:Larry, thank you again for this wonderful opportunity to try to make the history books. I'll take good care of your baby.

All right, Bruno, here are the things I know that should [might] make startup a breeze:

What you need is a propane supply that can be funneled down to a 1/8-inch or smaller hose, and a compressed air supply with a shutoff valve and a regulator with a range of, say, 0-30 PSIG. The trick will be almost entirely finding the air pressure that's just right.

My starting rig has a push-button valve and about 6 ft [2 m] of 3/16-inch [4-5 mm] ID rubber hose with a standard screw-on tire fitting on the end. That's a pretty draggy system, and Mike can probably provide something easier-flowing than that, which means you won't need as much pressure. The starting air tube is 1/4-inch OD, so you need to terminate with a small hose that fits snugly enough to stay on that pipe while you're applying air, but that can be wiggled off the pipe quickly once the engine starts. On the Elektra II I had to have 30 PSI on the regulator. I think you should start with about half that, because of probable lower resistance in the outfit. The right amount of air should excite the engine into a soft but definite 'howl' when you apply it. The easiest mistake to get into is trying to force too much air.

The best starting technique I've found is: Start the spark, start the air, then gradually open up the propane until it roars, and then add just a little more. Shut off the air - if it sustains, the power will drop noticeably and you can crank in a little more fuel yet. Cut the spark and disconnect the air hose and spark wires.

If all you get is bangs and pops, you probably don't have enough air pressure/flow. If you get roars but it doesn't sustain, or you get 'blowtorch' running, you probably have too much. Once it starts and is running properly, you can try throttling up and down with fuel adjustment, of course.

That should be about all there is to it.

L Cottrill

Thanks, Larry. I think I'll master the juggling act. :o)

Bruno Ogorelec wrote:Thanks, Larry. I think I'll master the juggling act. :o)

I couldn't test without my "third hand" - a brick that I use to hold down the push button that activates the HV spark coil. I probably should install a toggle switch or something. The button is getting pretty worn from contact with the bottom of the brick.

Crude but effective ...

L Cottrill

All right, here are the construction photos of how I finished him up.

Enjoy ...

L Cottrill

Here's a simple scale drawing showing the final dimensions for the new, improved Fo Mi Chin II. Note that I can't really measure such an object to the nearest .01 inch, but these should come pretty close to the truth. I included the extra 1 inch [approx.] that I ended up with. It was hard to get very accurate positioning of the intake spout because of working with the hulk of the old Fo Mi Chin, but everything should be close enough for it to start and run.

Hope you like it, Bruno, and that it kicks right off and runs for you!

L Cottrill

Very nice work, Larry.

I'll cross my fingers for your design and Bruno, of course.