Scott Vacuum Engine......

[ths]

Never think that there's no interest! I've missed quite a bit lately, but always find what you do to be worthwhile and interesting. May the orphanage continue to let well balanced and hard working engines into the world. Merry Christmas, Mr Drillin'. Hugh.

[Kim]

Hi David,
I doubt that anyone on this forum is upset by anything you're doing here.

I for one, have always enjoyed your posts. I would bet that I'm just one of the silent followers here.

For me, I don't have much familiarity with stirling or vacuum engines, so don't have a lot to say.  But your work is always interesting to me. Someday, I'm going to try my hand at one of these, and it will be that much easier because of what I've learned from following along with your work.

I realized it takes time and effort to post things, so if you choose to post less in the future, I would certainly understand.  But I would love to see you continue posting.

Thanks for what you have shared with us up till now!
Kim

[Jonfb64]

I'm still following but been distracted by christmas shoppping.

looking forward to the next video

Jon

[Stilldrillin]

Hugh, Kim, Jon.
Thanks Fellas!  It's nice to know my fumblings are being appreciated.......


A piece of s/s, 2mm x 75mm square, (£2. Ebay), was made into a piece of 55mm dia. round.

Drilled, to match the cyl head........




Recessed, 25thou deep, for shutter blade........




Window, cut out........




Piston's eye view. The top of the blade can bend outward, to relieve any unwanted pressure........




I assembled, loosely, no oil. Still with the c/i, (now undersize), polished piston.

Had a bit of a surprise, during engine warm up. It runs, on the hot air gun! 

<a href="https://www.youtube.com/watch?v=m-Chb3gnXqs" target="_blank">http://www.youtube.com/watch?v=m-Chb3gnXqs</a>


Official trial video........

<a href="https://www.youtube.com/watch?v=2KALEUREuEs" target="_blank">http://www.youtube.com/watch?v=2KALEUREuEs</a>


I think the next job, aught to be the twin wick burner. 


Thanks for looking in!

David D

[smfr]

Very nice, David! I like how it ran with the hot air gun, too!

Simon

[ths]

Not your average fumblings. Good to see it going so easily. It looks a fearsome creature, with the two burners and inlets. I can only imagine that it would be way down on the list for efficiency, but it's a visual winner, and has its own sound.

Cheers, Hugh.

[Roger B]

As you said "that'll do nicely" It's got an incredible sound   

[b.lindsey]

I'm still following along too. Hoping the stainless and graphite will solve the condensation issue. I ran into that with the RiderEricsson and know how frustrating it can be. Keep up the fine work, you have more fans than you know!

Bill

[Stilldrillin]

Simon, Hugh, Roger, Bill.
Thank you all, for your kind comments. They've given me a lift........

The hot air gun, was a complete surprise! 
I had warmed the cylinder/ hopper area, and decided to direct the heat inside the cyl. Prior to firing up the temporary burners.

No condensation, using the pre heat system! 

I've made a start, adapting the burner, to twin wicks. 
But. Seems I'm now booked for an 8 hour shift, entertaining a Little Person, tomorrow. No more shop time available, for several days........ 

Wishing all MEMers, everywhere. A very, Happy Christmas.

David D

[b.lindsey]

David, its the little people that will hopefully enjoy the fruits of our labors in the years to come...at least I hope they will come to appreciate them.  Little people time is good too, and I look forward to seeing my two g'kids over the holidays. My grandson is 3 and as they are upgrading his bedroom to a bigger boy room, my dau asked me to make a biplane themed bookshelf for him which I am working on now. He is (for now) really into airplanes

Bill

[Stilldrillin]

That's all quite true, and very satisfying Bill!

Mia has gone to her other Grandma's, for the night.

She's put out some reindeer food. Hoping they will find her, in the big city of Sheffield....... 


Good luck with the biplane! 

David D

[Stilldrillin]

I've had very little workshop time, these past weeks. But, have made some good, solid progress.

I took the top off the original burner......




And, made a twin wick burner........




The engine then proved to be a willing runner!

The shim valve. When releasing it's pressure, blew onto the flames. Bending them outward.

So, I filed the top edge of the "window", to direct the pressure more upwards. Better.......




It's really satisfying, when you begin to understand these engines.


The obligatory video.........

<a href="https://www.youtube.com/watch?v=vzi0t757Fx0" target="_blank">http://www.youtube.com/watch?v=vzi0t757Fx0</a>


Next job. We need an "eyebrow", to replace the hacksaw blade.


Also, I've noticed the mild steel shutter, is now scuffing the s/s port area. Will swap material, to brass shim........

Thanks for looking in!

David D

[b.lindsey]

David, why is it that removing the hacksaw blade extinguishes the flame?  It seems to burn ok before you hold the hacksaw blade over it.

Bill

[Zephyrin]

Nice thread and built, thanks to share and bravo for this fine runner !
The condensation rust, yes what a plague, a little drop of vaseline oil, when the engine is running and hot may help to prevent stucked parts for a while...
interesting experiments with the saw blade, hindering cold air intake and increasing speed.
The flamme position is obviously the weakest point of these engines and the most difficult to control.
I never understood how come flame eaters are so noisy, I made four, when compared to Stirling engines...

 

[Stilldrillin]

David, why is it that removing the hacksaw blade extinguishes the flame?  It seems to burn ok before you hold the hacksaw blade over it.

Bill

Hi Bill. Good question!

The valve is based on the Poppin design. To be blown off it's seal, by positive pressure.
Poppin's port area is a flat face. So, gasses are blown vertically away.

This one has the shutter frame, above the port area. Consequently, gasses are bounced towards the flame, (see bent flame, in last still pic).
This acts as a "governor".

Separating the in/ out gasses, with the blade, allows revs to rise.
Removing the blade allows the higher rev's gas velocity, to blow out the flame.     (I guess)...... 

The wicks are, at present, too high. Need to shorten their tubes by a few mm's.

It's all an experiment! 

David D