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What sort of things DO NOT inspire you

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SillyOldDuffer23/02/2020 17:34:52
5913 forum posts
1280 photos
Posted by KWIL on 23/02/2020 14:39:24:

My only interest in "hot air" machines was when I used one in reverse, mechanical power (electric motor) IN, very (VERY) cold out. Actually pretty close to absolute zero.

Good point! I jumped to the conclusion that engines are always about power out, completely forgetting refrigerators!

Obviously Model Engineering is Freudian. Engines that move the world involve hot, steamy action, whereas the other way round is frigid and no fun at all...

Not that it matters at my age.

devil

JA23/02/2020 17:50:27
936 forum posts
51 photos
Posted by KWIL on 23/02/2020 14:39:24:

My only interest in "hot air" machines was when I used one in reverse, mechanical power (electric motor) IN, very (VERY) cold out. Actually pretty close to absolute zero.

What gas were you using? Helium?

JA

KWIL23/02/2020 19:29:04
3261 forum posts
63 photos

Yes, cold end was vacuum contained also at extremely low pressure.

Neil Wyatt23/02/2020 20:11:50
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17970 forum posts
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Posted by JA on 23/02/2020 17:14:50:
Posted by Neil Wyatt on 23/02/2020 13:26:03:
Posted by JA on 23/02/2020 13:00:02:

What I don't understand is the fascination the model engineering fraternity has with hot air engines. While most other model engines develop some power hot air engines are pathetic (except for a very few).

JA

But they are more efficient than internal combustion engines...

Neil

Are they?

Most operate at near atmospheric pressures and low temperatures, not conditions for good efficiency.

I agree that they have to be well made, to work at all.

JA

A google for 'stirling cycle efficiency' will leave your head spinning...

In theory a Stirling engine can approach it's Carnot theory limit (based on the temperature difference of the hot and cold ends. Internal combustion can use higher temperatures, but at a much lower Carnot efficiency with all that hot exhaust gas so most industrial Stirling engines are more efficient than most IC engines. They use less fuel but cost more to build... According to wikipedia and some other sources up to a round 100-150kW Stirling engines are cost effective, but unfortunately a much lower power to weight ratio means they are typically suited to fixed installations.

Neil

JA23/02/2020 20:59:02
936 forum posts
51 photos
Posted by Neil Wyatt on 23/02/2020 20:11:50:
Posted by JA on 23/02/2020 17:14:50:
Posted by Neil Wyatt on 23/02/2020 13:26:03:
Posted by JA on 23/02/2020 13:00:02:

What I don't understand is the fascination the model engineering fraternity has with hot air engines. While most other model engines develop some power hot air engines are pathetic (except for a very few).

JA

But they are more efficient than internal combustion engines...

Neil

Are they?

Most operate at near atmospheric pressures and low temperatures, not conditions for good efficiency.

I agree that they have to be well made, to work at all.

JA

A google for 'stirling cycle efficiency' will leave your head spinning...

In theory a Stirling engine can approach it's Carnot theory limit (based on the temperature difference of the hot and cold ends. Internal combustion can use higher temperatures, but at a much lower Carnot efficiency with all that hot exhaust gas so most industrial Stirling engines are more efficient than most IC engines. They use less fuel but cost more to build... According to wikipedia and some other sources up to a round 100-150kW Stirling engines are cost effective, but unfortunately a much lower power to weight ratio means they are typically suited to fixed installations.

Neil

Your head spin.... No, these are normal thermodynamic performance calculations.

I first met the Stirling cycle in the early 1960s with an article on the Phillips engine in the New Scientist. It struck me as a marvellous engine. However having spent most of my working life with engines I realise why they are only met in niche applications. Some of the reasons you have already alluded to. Other include non-combustion heat sources such as radioactivity.

If I have the time, and will, in the next few days I may sit down and calculate the theoretical performance differences of a model 4 stroke IC and a Stirling engine.

JA

Peter G. Shaw23/02/2020 21:27:32
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1121 forum posts
44 photos

Modern music, or what passes for music.

Modern art: a few years ago, my wife and I visited Chatsworth House and on one of the corridors was an exhibition of painting. It looked just like a child's daubs using different colours. And as for Tracey Emin's unmade bed, well words fail me.

Peter G. Shaw

paul rayner23/02/2020 22:14:51
160 forum posts
44 photos

politicians

 

sorry I know we shouldn't get political, but, well I do find them uninspiring.

Edited By paul rayner on 23/02/2020 22:17:14

Baz23/02/2020 22:24:18
407 forum posts

Got to agree with Peter, modern music and art. As for politicians I am lost for printable words.

Peter G. Shaw25/02/2020 13:02:18
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1121 forum posts
44 photos

Just another couple of items that do not inspire me:

Mobile & these so-called smart 'phones. Why do I want to be available to all and sundry 24/7? Having said that, as someone who had a (fortunately) mild heart attack five years ago, I will concede that a basic mobile 'phone could now be a lifesaver if I ever had another attack, especially if the internal address book has been set up with the ICE (1, 2, 3 as necessary) commands. (ICE = In Case of Emergency). However, mine is switched off probably 99% of the time.

The other totally uninspiring item is closely allied to smart 'phones. I refer to things like Reddit, Facebook, etc. Do I really, really need to know the ins & outs of someone elses life? And do I want to tell everyone else my innermost thoughts? Do I heck!

After all, how did we manage 30 or more years ago? A trip out from the office meant peace & quiet with no-one contacting you to either ask inane questions, or worse, keeping you abreast of office gossip. I suppose FOMO accounts for a lot of it, but not for me - I really do not care if I miss out!. (FOMO = Fear Of Missing Out)

Peter G. Shaw

Brian H25/02/2020 13:06:58
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1672 forum posts
109 photos

Mobile 'phones.

Martin Kyte25/02/2020 13:56:27
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1897 forum posts
34 photos

Tattoos

Mick B125/02/2020 15:06:07
1604 forum posts
85 photos

Idiot 'personality' celebs with no apparent talents or skills.

Mind you, they managed to *inspire* me to bother to write that... blush

Edited By Mick B1 on 25/02/2020 15:06:30

Johnboy2525/02/2020 15:15:38
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259 forum posts
3 photos

Yes - I can not see the point in ‘body art’ on the basis my human frame is deteriorating quickly enough with old age without having tattoos making it look worse! Who or what designed the human body did in my option a pretty good job without embroilIng it with what ever someone thinks that ‘it looks good”! 😋

(yes I know - I’m an ‘old git’🤭

Steviegtr25/02/2020 15:34:23
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1262 forum posts
119 photos

Sunday cyclists blocking the road.

Potholes.

People who leave the lift after letting one go.!

John Haine25/02/2020 16:56:21
3166 forum posts
171 photos

As a cyclist I can vouch that the combination of potholes and impatient drivers is extremely uninspiring.

bill ellis25/02/2020 20:37:48
71 forum posts
2 photos

As a cyclist (not usually Sunday as there are too many weekend warriors winding motorists up) and the driver of one of those horrible 4x4 Land Rover things I should be hated by everyone. Maybe a caravan would help spread the love cheeky.

Dave Halford25/02/2020 20:57:11
801 forum posts
8 photos
Posted by bill ellis on 25/02/2020 20:37:48:

As a cyclist (not usually Sunday as there are too many weekend warriors winding motorists up) and the driver of one of those horrible 4x4 Land Rover things I should be hated by everyone. Maybe a caravan would help spread the love cheeky.

Bet you look great in Lyrca too face 7

Mike Poole25/02/2020 21:44:56
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2607 forum posts
63 photos

c2105084-5119-4aa8-ac3b-a6cea24e8a64.jpeg
 

You could always pop one of these Stirling’s in your car.

Mike

Edited By Mike Poole on 25/02/2020 21:45:24

fizzy26/02/2020 00:22:48
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1716 forum posts
116 photos

people who tell you that you have to manufacture a gap when silver soldering...absolute cods!! last thing you ever want to do".......and I should know

Grindstone Cowboy26/02/2020 00:47:12
310 forum posts
27 photos

People saying "invite" when they mean "invitation", and "could of" when they mean "could have", and "off of" when "off is all that is required angry

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