Author Topic: Scott Vacuum Engine......  (Read 50360 times)

Offline Stilldrillin

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Scott Vacuum Engine......
« on: October 25, 2014, 03:24:16 PM »

Introducing Scott. Another of my orphan engines.

Arrived a couple of years ago. Been patiently waiting in the cupboard.  :-\

Never run. (I don't think)........




Badly packed, on top of the wad of drawings. Which were penetrated by the crankshaft.......




The shaft was bent, and flywheel distorted.
Rather proud of myself, at the time. I made a ballrace nudger. Which got it back, to within a couple of thou'.  ;)

As it arrived. It was impossible to screw the valve mechanism together, tight enough........  :facepalm2:




I dimpled the cross shaft, for the grub screw. Then made a temporary return spring........




No joy! The shutter arrangement is much too light n floppy. Had a few pops, only.

After I'd caught my finger in the guillotine, for the third time. I decided it was time for some mods.......  :)




So......

The engine part is fine. The valve part is 'orrible.

I need some info, as to which is the best system to get the flame safely into the cylinder, at the correct time.

Some systems are eccentric driven, rather than a cam. I guess that is for quicker open/ close action.
But an eccentric will give positive motion, in both directions.

I can visualise a push/pull or twisting rod, along the side. How does it turn the corner, to the port?

Anyone any ideas? Crap o cad/ pics/ vids, gratefully accepted.

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Jasonb

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Re: Scott Vacuum Engine......
« Reply #1 on: October 25, 2014, 04:36:07 PM »
John (Bogstandard) did quite a detailed build of this and the alterations to the springs and block that were needed to get it to run. May have been on Here, Madmodder or HMEM but not sure if teh imahes will still be in the thread.

Failing that he does post a bit on ME Forum so may spot a thread there is you start one
« Last Edit: October 25, 2014, 04:41:07 PM by Jasonb »

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #2 on: October 25, 2014, 04:48:46 PM »
Thanks for that, Jason.  :ThumbsUp:

It's here.... http://www.modelenginemaker.com/index.php/topic,158.0.html

I also followed his build, in real time, on Modder........

Frankly, (you know me)...... I want to completely change the valve mechanism.  :facepalm2:

To something more reliable.  :D

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

fcheslop

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Re: Scott Vacuum Engine......
« Reply #3 on: October 25, 2014, 05:21:43 PM »
Maybe a face cam and a side shaft arrangement :mischief:
That will get rid of the awful valve set up.
http://www.vakuum-und-heisse-gase.de/StartseiteVakuummotoren.html  :ThumbsUp: :ThumbsUp:
Probably telling me granny how to suck eggs .You want about 110 to 120 degrees of valve duration and fast lift n close ramp
Cheers marra
« Last Edit: October 25, 2014, 05:24:57 PM by fcheslop »

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #4 on: October 28, 2014, 09:15:31 AM »
Well, Frazer.......

It looks like it's just me an you. Who are barmy enough, to struggle with these crazy machines.  :ShakeHead:

That's a great site! Many good ideas. (Once I'd found the arrow, down the bottom of the page).  :embarassed:

Would be even better, if I could read it in English. (I guess/ hope, someone will know how).  :headscratch:

Frankly, I like the Bengs Nick, system, on the engine I've just recycled. I'm exploring possibilities for a copy version.......  ;)

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Bluechip

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Re: Scott Vacuum Engine......
« Reply #5 on: October 28, 2014, 09:46:55 AM »
Well, Frazer.......

It looks like it's just me an you. Who are barmy enough, to struggle with these crazy machines.  :ShakeHead:

10/10.   Can find no fault with that conclusion.    :Lol:

Would be even better, if I could read it in English. (I guess/ hope, someone will know how).  :headscratch:

'Translate with Bing' works here 



Offline wagnmkr

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Re: Scott Vacuum Engine......
« Reply #6 on: October 28, 2014, 11:20:20 AM »
Google translate worked for me.

Tom
I was cut out to be rich ... but ... I was sown up all wrong!

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #7 on: October 28, 2014, 12:53:15 PM »
Dave.

Well, ar!  :agree:   :-\


Dave/ Tom.

Thanks Chaps! Both systems seem to do the business. Will peruse deeper, this eve.

At the moment, I'm struggling to press the cylinder out of the hopper casting....... (There's a small coolant leak).  :facepalm:

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline Roger B

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Re: Scott Vacuum Engine......
« Reply #8 on: October 28, 2014, 05:53:22 PM »
If the online translators struggle with some of the technical German I may be able to help.
Best regards

Roger

fcheslop

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Re: Scott Vacuum Engine......
« Reply #9 on: October 28, 2014, 07:44:35 PM »
Hi David, yep its a minority sport
Theres far more interest on the continent and some very helpful guys and girls
http://www.bloooo.fr/forums/viewtopic.php?f=31&t=4018&start=15 . One of my favourite sites to browse and some nice builds Iv been looking into an Essex build.
The only prob Iv got is learning French,Dutch and German and Iv never gotten the hang of English
Should be good entertainment
Just had a gleg at that base casting as you rightly say go for the Bengs or Poppin valve idea .Will it be possible to mount a pivot on the lower face of the base casting and an extended pin to run on the cam???
cheers ma dears
« Last Edit: October 28, 2014, 07:51:37 PM by fcheslop »

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #10 on: October 28, 2014, 08:50:07 PM »
Roger.
Thanks for the offer! The translation's quirky. But quite sufficient to understand, with pictures......  ;)

Frazer.
Yes. As you say, good entertainment. Or total confusion!   :o

Pivot on the lower face? What's wrong with the existing pivot? Or...... Am I missing something? :headscratch:

It's a bit late now! Roughed out slot.......




David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

fcheslop

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Re: Scott Vacuum Engine......
« Reply #11 on: October 28, 2014, 11:22:40 PM »
Hi David, no problems with that slot. Theres more than one way to skin a cat

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #12 on: November 07, 2014, 09:16:13 PM »
Progressing. Slowly........  ::)

Milled a matching slot, and 4 retaining holes, in the hopper........




Matched up, nicely........




It needed a widget...... M3 thread in one end, 3/16" hole in the other, and a 9degree bend in between.

Turned the big end, and tapped m3. Held in the rotary table, at 9*, spot faced and drilled 3/16 to centre.......




On to a 3/16" mandrel. Turn small dia........




M3 studding. Turn radius........




Couple of flats. Loctited, to the tubular operating arm........




Bottom of stroke.......




Top.........




I'm quite pleased, how it's gone together, so far.

I've (finally), read up the Poppin plans, and think the lightweight valve is the way to go.
Bought some 5thou steel shim. If I can cut it, and keep it flat. I might be in with a chance!

The present return spring is much too stiff. I've made a better action, with a small coil spring, under the cam arm.
But, I don't want to abandon the leaf spring, just yet.

Does anyone know where I can get a sensible length, of 1/4" x .012" spring steel?

Thanks for looking in!  :cheers:

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!

Offline JonIndigoman

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Re: Scott Vacuum Engine......
« Reply #13 on: November 07, 2014, 09:47:25 PM »
The coil spring in a tape measure is a preaty handy piece of spring steel. Hope that may be of use to you.

cheers Jon

Offline Stilldrillin

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Re: Scott Vacuum Engine......
« Reply #14 on: November 07, 2014, 10:43:32 PM »
The coil spring in a tape measure is a preaty handy piece of spring steel. Hope that may be of use to you.

cheers Jon

That's a great idea, Jon!  :whoohoo:   Thank you!  :ThumbsUp:

Now..... Where do all the old tapes go to?  :headscratch:

David D
David.
Still modifying bits of metal... Occasionally, making an improvement!
Still drilling holes... Sometimes, in the right place!