Search found 17 matches

by MikeB
Fri Jul 05, 2019 9:49 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Torque question.
Replies: 3
Views: 446

Re: Torque question.

I would say that this is a question of finding the 'sweet spot'. If you think about it, if you have a displacer stroke of zero, then the working fluid doesn't get moved from hot to cold to hot, so no energy can be obtained, but at the other extreme, if you have an incredibly long displacer (and stro...
by MikeB
Tue Jun 25, 2019 6:19 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Stirling engine software
Replies: 7
Views: 4820

Re: Stirling engine software

Nlog looks to be a very complex bit of software - in a commercial environment you would have to pay a lot of money to get anyone to write anything that sophisticated, but having said that half an hour to initialise (as mentioned on that site) does seem inordinately slow.
by MikeB
Thu Jun 20, 2019 7:09 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Proposed Air Cooling Tower
Replies: 7
Views: 772

Re: Proposed Air Cooling Tower

How long would you expect this to run? You would get a very high rate of evaporation from this, which would aid the cooling, but might make it 'unexpectedly' run dry.
by MikeB
Thu Mar 28, 2019 7:05 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: My stirling engine school project
Replies: 28
Views: 4331

Re: My stirling engine school project

That diagram still shows a large space behind your diaphram, which will be detrimental to the performance of the engine - make that as small as possible, so that the pipe essentially just goes straight onto the back of the diaphram.
by MikeB
Fri Jan 04, 2019 7:19 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Burnt pancake displacer (carbon foam)
Replies: 8
Views: 3796

Re: Burnt pancake displacer (carbon foam)

I can see this kind of material being useful for displacers, particularly if you are using an inert gas, but surely not very useful for "open air" applications (such as round the hot cap, as suggested). Basically, what you have is open-cell graphite, so given enough heat, and any amount of oxygen, i...
by MikeB
Fri Aug 31, 2018 2:41 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Alpha vs Beta
Replies: 3
Views: 2763

Re: Alpha vs Beta

So if the power-to-weight advantage is due to the 1:1 ratio, why isn't that used for the other configurations?
by MikeB
Fri Aug 31, 2018 2:36 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Dual stirling generators electrically heated
Replies: 16
Views: 3997

Re: Dual stirling generators electrically heated

Running two engines off a single flame is not the same thing - the flame isn't dependant on the output of either engine. Unfortunately, every type of engine has an upper-limit to efficiency - this is often described as being a "Theoretical Limit" but that isn't really good grammar, as there is nothi...
by MikeB
Fri Jun 15, 2018 5:18 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Tesla's "Ambient Heat Engine" Experiment
Replies: 33
Views: 19589

Re: Tesla's "Ambient Heat Engine" Experiment

Is that a double displacer there? and 180 degrees out of phase with each other?
by MikeB
Wed Jan 10, 2018 6:13 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Tesla's "Ambient Heat Engine" Experiment
Replies: 33
Views: 19589

Re: Tesla's "Ambient Heat Engine" Experiment

So, if no heat ever goes into the ice, what effect does it have on the system???? I think what Tesla was really getting at, (probably incorrectly) was that if the engine was 100% efficient (no chance) then the _output_ of the engine could be used to cool the ice/cold end. Which sounds to me rather l...
by MikeB
Fri May 19, 2017 6:25 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Multi cylinder Stirling engine question.
Replies: 4
Views: 4042

Re: Multi cylinder Stirling engine question.

What info are you looking for? I'd have thought that the problems involved in building an eight cylinder engine are pretty much the same as for twelve cylinders, just with different angles. (And not necessarily then - sometimes multi-cylinder IC engine designs are merely two/three/four cylinder desi...
by MikeB
Tue Apr 25, 2017 4:59 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Volum alfa model
Replies: 26
Views: 11767

Re: Volum alfa model

That picture shows the cylinder being vented at the right hand side - is that a mistake in the drawing, or how you've built it??
by MikeB
Tue Apr 25, 2017 4:50 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Carnot and Stirling cycles
Replies: 3
Views: 3639

Re: Carnot and Stirling cycles

Even in an ideal Stirling Engine the piston has to move to draw power, which will result in a small change in volume.
by MikeB
Tue Mar 14, 2017 8:58 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Stirling Generators
Replies: 8
Views: 6169

Re: Stirling Generators

Do you want enough power to run a computer, or just enough to be able to charge a device - there's a massive difference between the two figures.
by MikeB
Fri Oct 14, 2016 4:10 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Tesla's Heat Engine
Replies: 20
Views: 10984

Re: Tesla's Heat Engine

Sounds to me like you are talking about a variation on what is currently known as an "Air Source Heat Pump"
I can't say I understand it well enough though, to do the maths to check whether it is theoretically possible or not.
by MikeB
Fri Sep 04, 2015 7:09 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: varible phasing
Replies: 27
Views: 16624

Re: varible phasing

For the record, you can also get small ball bearings out of certain types of computer back-up tapes - I've grabbed a few from DLT tapes.
But am I reading you correctly - the 'proper' ball bearings have _more_ friction than your 'hand made' bearings?