Fo Mi Chin Re-work [Version II]

Moderator: Mike Everman

re: Fo Mi Chin Re-work [Version II]

Postby Mark » Thu Apr 07, 2005 3:17 pm

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.
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re: Fo Mi Chin Re-work [Version II]

Postby larry cottrill » Thu Apr 07, 2005 3:33 pm

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".

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re: Fo Mi Chin Re-work [Version II]

Postby Mark » Fri Apr 08, 2005 8:01 am

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.
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re: Fo Mi Chin Re-work [Version II]

Postby Anthony » Fri Apr 08, 2005 10:01 pm

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...
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re: Fo Mi Chin Re-work [Version II]

Postby resosys » Fri Apr 08, 2005 10:32 pm

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...
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re: Fo Mi Chin Re-work [Version II]

Postby larry cottrill » Mon Apr 11, 2005 3:57 am

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.

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Ready to Roar ... or something

Postby larry cottrill » Tue Apr 12, 2005 3:10 am

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 ...

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Re: Ready to Roar ... or something

Postby Mike Everman » Tue Apr 12, 2005 4:38 am

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. ;-)
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Re: Ready to Roar ... or something

Postby Bruno Ogorelec » Tue Apr 12, 2005 11:37 am

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.
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Suggestions for Starting

Postby larry cottrill » Tue Apr 12, 2005 1:26 pm

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.

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re: Fo Mi Chin Re-work [Version II]

Postby Bruno Ogorelec » Tue Apr 12, 2005 2:04 pm

Thanks, Larry. I think I'll master the juggling act. :o)
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Re: re: Fo Mi Chin Re-work [Version II]

Postby larry cottrill » Wed Apr 13, 2005 1:51 pm

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 ...

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Final Construction Photos At Last

Postby larry cottrill » Wed Apr 13, 2005 5:31 pm

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

Enjoy ...

L Cottrill
Attachments
FMCII_intake_welded_side_crop1_small.jpg
Side view of the weld joining the intake half-shell to the notched tailpipe front end, before shaping the front end of the spout lip. Photo Copyright 2005 Larry Cottrill
FMCII_intake_welded_side_crop1_small.jpg (148.61 KiB) Viewed 5335 times
FMCII_intake_finished_front_crop1_small.jpg
Front and side view of the finished intake/tailpipe assembly. The downturned lip is formed entirely by heating and hammering. Photo Copyright 2005 Larry Cottrill
FMCII_intake_finished_front_crop1_small.jpg (144.17 KiB) Viewed 5340 times
FMCII_intake_finished_bottom_crop1_small.jpg
Bottom view of the finished intake/tailpipe assembly. The spout into the chamber is clearly shown. Photo Copyright 2005 Larry Cottrill
FMCII_intake_finished_bottom_crop1_small.jpg (145.23 KiB) Viewed 5334 times
FMCII_intake_finished_rear_crop1_small.jpg
Rear view of the finished intake/tailpipe assembly. Photo Copyright 2005 Larry Cottrill
FMCII_intake_finished_rear_crop1_small.jpg (138.84 KiB) Viewed 5337 times
FMCII_chamber_slotted_crop1_small.jpg
The rear of the chamber slotted out for the intake assembly - done by melting the edge back with a small flame. Photo Copyright 2005 Larry Cottrill
FMCII_chamber_slotted_crop1_small.jpg (165.63 KiB) Viewed 5337 times
FMCII_chamber_intake_depth_crop1_small.jpg
This 'top view' shot attempts to show how far the intake assembly will penetrate into the chamber. Photo Copyright 2005 Larry Cottrill
FMCII_chamber_intake_depth_crop1_small.jpg (171.81 KiB) Viewed 5336 times
FMCII_chamber_intake_welded_crop1_small.jpg
The finished weld between the pipe assembly and the chamber - yes, I had to patch a few holes. I also added the air/fuel pipe assembly for this shot. Photo Copyright 2005 Larry Cottrill
FMCII_chamber_intake_welded_crop1_small.jpg (169.5 KiB) Viewed 5334 times
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Final Dimensions [more or less]

Postby larry cottrill » Wed Apr 13, 2005 5:50 pm

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
Attachments
Fo_Mi_Chin_Ver_II_scale.gif
Scale drawing of finished Fo Mi Chin II, showing the actual "as built" final dimensions. Drawing Copyright 2005 Larry Cottrill
Fo_Mi_Chin_Ver_II_scale.gif (5.93 KiB) Viewed 5333 times
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re: Fo Mi Chin Re-work [Version II]

Postby mk » Wed Apr 13, 2005 5:59 pm

Very nice work, Larry.

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