Search found 2198 matches

by Ian S C
Sat Apr 20, 2019 3:58 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

True, I could only find information for PTFE on steel and PTFE on PTFE, both 0.04, no mention of aluminium. Andy Ross in his book "Making Stirling Engines",(free down load), uses a Teflon resin paint called Xylan on aluminium alloy pistons, this stuff is applied professionally and baked on. He used ...
by Ian S C
Fri Apr 19, 2019 3:55 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

I'm still a bit worried about the aluminium power cylinder, I would like it better with a steel liner, aluminium is horrible for galling regardless of what it is running against, anodized, yes it's OK, hard chromed OK.
Ian S C
by Ian S C
Sun Apr 14, 2019 1:57 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

The piston is cast iron with no rings, piston rings are the death of Stirling Engines. The cylinder is made of mild steel(a bit of scrap), the hot end is made from a stainless steel kitchen container. The crankshaft has two throws, the long one for the displacer is 7/8", and the power crank 5/8" ( I...
by Ian S C
Sat Apr 13, 2019 4:21 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

60,000 hrs is a long time, I would imagine that at the end of that, it would end up in the scrap metal yard, by that time I would hope for an upgrade to an improved motor. One of the most important parts of a Stirling Engine is the cooling system, that was one thing about automotive use, the big rad...
by Ian S C
Fri Apr 12, 2019 3:14 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

I don't know where you are ? USA, have a look for a stainless steel kitchen bench, maybe some dumpster diving needed here, or some recycling place, another source would be a stainless fridge, or other kitchen ware like a microwave oven. You would of course need a bit of welding with a TIG welder. My...
by Ian S C
Thu Apr 11, 2019 3:47 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Melvin Engine
Replies: 11
Views: 203

Re: Melvin Engine

Looks interesting. I would change the hot end for stainless steel, mild steel after a while gets corroded inside, and after a while will droop possibly fouling the displacer. Stainless is the best for the displacer too as it has a higher resistance to heat conduction, and can generally be made light...
by Ian S C
Mon Apr 01, 2019 2:05 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Stirling engine won't run
Replies: 10
Views: 415

Re: Stirling engine won't run

Pretty cool when the wheels start turning on something you built your self. Try a heavier flywheel, you might get a bit more power, on my tin can motor I used 4 old CDs.
Ian S C
by Ian S C
Sat Mar 30, 2019 1:35 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Square pistons/cylinders
Replies: 7
Views: 224

Re: Square pistons/cylinders

There is always the possibility of using a block of graphite as the piston. Over all an interesting project. A similar motor I have read of was a rotary engine in which the cylinders and crankcase rotate(as in the rotary aircraft engines of WW1), I imagine your motor as horizontal with the crankshaf...
by Ian S C
Sat Mar 30, 2019 1:23 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: My stirling engine school project
Replies: 28
Views: 1513

Re: My stirling engine school project

Looks a nice compact design.
Ian S C
by Ian S C
Fri Mar 29, 2019 1:12 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Square pistons/cylinders
Replies: 7
Views: 224

Re: Square pistons/cylinders

The main problem that I see is getting a good seal specially at the corners, even if left with a radius, round holes are always easiest( no corners). I think it sounds like an interesting design, a lot bigger than my biggest. Bore 2 1/4", power stroke 1 3/8". Ian S C Test 070 (640x480).jpg
by Ian S C
Thu Mar 28, 2019 2:36 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: My stirling engine school project
Replies: 28
Views: 1513

Re: My stirling engine school project

That looks ok, but you may find it easier to heat the hot end if you lay it down so that the displace is horizontal, or even a bit further so that the displacer is hanging down, and you can put the heat source under the end. The last way does make the crankshaft rather high, but if you look for pict...
by Ian S C
Thu Mar 28, 2019 2:27 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Square pistons/cylinders
Replies: 7
Views: 224

Re: Square pistons/cylinders

The cylinder of a Stirling Engine not having piston rings must be more accurate than an IC motor or steam engine, while it is possible to make square power units(you can't call a square a cylinder), there have been steam engines made that way. You don't really want steel on steel in rubbing contact....
by Ian S C
Wed Mar 27, 2019 1:20 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: My stirling engine school project
Replies: 28
Views: 1513

Re: My stirling engine school project

Roughly, the displacer is 1.5 times the power cylinder ie a ratio that you will come across if you read much on Stirling Engines ( 1.5 : 1), In this form it is as simple as it gets, and the power piston can be replaced with a diaphragm. With tin can motors the displacer is usually a bit bigger than ...
by Ian S C
Tue Mar 26, 2019 3:05 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: My stirling engine school project
Replies: 28
Views: 1513

Re: My stirling engine school project

If you can't machine, or other wise form two cylinders and fitting pistons I would suggest forgetting the ALPHA type motor, and build a GAMMA motor in which the power piston can be replaced with a diaphragm. The ALPHA motor does need a bit of extra work.

Ian S C
by Ian S C
Sun Mar 24, 2019 2:52 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Beta Rhombic Drive Motor
Replies: 1
Views: 144

Re: Beta Rhombic Drive Motor

Vjdeep, what is the piston made of? It is best if no rings are used, but a close fit in the bore. Piston rings cause high friction on the cylinder wall, and only really work properly with the high pressure if an IC engine, or the steam of a steam engine, even there the spring pressure against the cy...