Author Topic: Strictly.... “ Hot Air “  (Read 71664 times)

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #45 on: January 14, 2018, 11:25:41 AM »
Good morning.

The tin does have a slight taper but as the air on this engine is supposed to travel through it rather than round it, no problem!

Andy, progress is slow but sure. If you recall I mentioned that the water jacket core box that was used many times by the lads at Rhuddlan was wrong? The core was actually longer than the casting!! They never told me about the problem, they just removed the excess in the core shop. This fault only became known when my father in law and I tried to mould a platform at the Buckley foundry. In trying to shorten the cast Aluminium box I managed to break it.

Jo, I have many spare Iron castings for this engine but no platforms, cylinders or flywheels. And I don’t have a full set of Gunmetal linkages. In making inquiries about more links it seems the Brass foundry has mislaid my patterns at the moment.

Cheers Graham.

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #46 on: January 15, 2018, 07:58:51 PM »
Hello All.

I found this hidden away on a shelf in the workshop a few days ago. I'd almost forgotten I'd built it.

<a href="https://www.youtube.com/watch?v=_0MZLg5v4zc" target="_blank">http://www.youtube.com/watch?v=_0MZLg5v4zc</a>

Cheers Graham.

Offline Perry

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Re: Strictly.... “ Hot Air “
« Reply #47 on: January 15, 2018, 09:32:15 PM »
thats so entertaining, nice marble stirling  :ThumbsUp: nice

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #48 on: January 16, 2018, 10:18:42 AM »
Soldering tin lids back on.
I had a practice at soldering the lid back on to a tuna tin yesterday using an electric soldering iron and 60/40 blowpipe  solder. The tin was stuffed with steel wool to simulate the recommended stainless steel pan scourers.

Hi Graham - is that how you made your displacers and how many 1/8" holes did you put in your displacers?

Andy


Offline Bluechip

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Re: Strictly.... “ Hot Air “
« Reply #49 on: January 16, 2018, 10:29:40 AM »
Not quite 'Off-Topic' but sort of relevant:

www.ebay.co.uk/itm/Tattoo-Stainless-Steel-Cotton-Disinfection-Container-Tank-Alcohol-Canister-J7/292397617230?_trksid=p2485497.m4902.l9144

I wonder if these would be suitable for displacers ?

Probably nowhere near the size required for this engine but perchance for others.

Dave

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #50 on: January 16, 2018, 11:06:30 AM »
Good morning Andy.

Yes that’s exactly what the finished regenerative displacer piston should look like before drilling the holes.

On the two recently built and rebuilt engines we went for 4 holes at 1/2” diameter placed 90 degrees offset between the top and bottom.

The most delicate part of the operation is to get the displacer piston rod hole accurately centred and drilled without it snagging the Steel wool within. About a week ago Alan came in from the workshop holding what looked like something that had been through a shredder, yes, it had snagged, an hour or so’s work wasted.

Cheers Graham.

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #51 on: January 16, 2018, 11:56:12 AM »
Update.

Despite a recent break in at the Brass foundry that I’ve used for over 30 years now, my wooden patterns are safe.

I’ve ordered 6 sets of “ link motion “ castings for the half scale Robinson hot air engine. They’re being done in Brass this time as they very rarely do Gun metal these days.

I’m now in the process of getting the relevant patterns together for a small run of of castings. I’m hoping to have 6 kits available from a mixture of leftovers and new Iron parts within a month or so.

Cheers Graham.

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #52 on: January 16, 2018, 01:17:02 PM »
Hi Graham, pity I recently sold my Weirauch HW80 air rifle which would have put neat .22 holes throgh the tin.   :)
Andy

Offline Jasonb

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Re: Strictly.... “ Hot Air “
« Reply #53 on: January 16, 2018, 04:22:01 PM »
If Graham advocates 1/2" holes then you may as well get a tin, drill the holes and prize out the contents before poking the scouring pads in via the holes, saves all that soldering :)

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #54 on: January 16, 2018, 06:26:44 PM »
Yes Jason I thought about removing the contents through 1/2" holes and inserting stainless steel scouring pads in the other direction but the material might fall out through the holes.
 I expect Graham has tested these options and will comment. The plans state "Cover both faces with 1/8" holes leave 1/2" band around circumference un drilled". Perhaps Graham has found fewer 1/2" holes more effective. I haven't found any pictures of Robinson regenerative displacers.
Andy

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #55 on: January 16, 2018, 07:02:16 PM »
Hi Andy.

Drilling 4 holes either side is far less time consuming than many 1/8" holes, otherwise there's nothing to be gained!

Here's a picture of the internals from a 1905 book, Modern engines and power generators.

Cheers Graham.

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #56 on: January 17, 2018, 12:49:48 PM »
Thanks Dave, well spotted those stainless steel tins would be useful to hot air engine builders. The 9cm tin is closest to my requirements.
Andy

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #57 on: January 23, 2018, 06:33:35 PM »
Wonderful service!!

Look at the contents of a surprise parcel that arrived by courier this morning.

We're one step closer to a small run of Robinson hot air engine kits.

Cheers Graham.

Offline Jo

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Re: Strictly.... “ Hot Air “
« Reply #58 on: January 23, 2018, 06:49:04 PM »
Castings  :naughty:

I can tell you know how to chat up a young lady Graham  :embarassed:

Jo
Enjoyment is more important than achievement.

Offline b.lindsey

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Re: Strictly.... “ Hot Air “
« Reply #59 on: January 23, 2018, 06:51:24 PM »
I think you should reserve one set for shipment to the USA.  :naughty:

Bill

 

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