Stirling 1

Moderator: stan.hornbaker

Forum rules
Be nice!

Stirling 1

Postby none » Sun Mar 02, 2003 10:32 am

Hello,




I hope you will not mind mw posting a question not related to one of
your own designs. I have not found any other forum dealing only in
Stirling engines.




I have made the single piston Stirling engine as described in the book
"Building Stirling One - A One Piston Hot Air Engine" by E.T.
Warbrooke. This is quite an unusual engine in that it does not have a
displacer piston.




I have slightly modified the design :o) by using a test tube for the
heater tube and a graphite piston. Needless to say my engine will not
run :o(




I have tested the joint between the heater tube and power cylinder
under water and am 100% sure that this does not leak (it is sealed
with an O-ring).




When fully assembled, the piston seems to have a good bounce when the
flywheel is spun by hand. However, I did also tested the piston
cylinder seal under water and there was a little air leaking out under
compression. At this point I would like to point out that I am rather
new to ME, so I am assuming that my manufacturing skills are at fault.
Hence I am currently re-making the cylinder and piston assembly to see
if I can make a piston / cylinder with better sealing.




This type of engine being without a displacer, does anyone have any
information as to any "magic" dimensions for this type of engine. My
heater tube is slightly longer than than described in the design, but
I would not have thought that this would have made so much difference
that the engine would not run.




Finally, there is no information in the book as to what the position
the piston should be at when the engine is assembled. Does this not
make a difference ? I would have thought that it would because it
increase the amount of air in the engine when at rest. Also, how long
should such an engine take to "warm up" before a flick of the flywheel
will usher it into life (also not included in the book) ?




Sorry for so many questions !




Any information would be greatfully recieved.


Many thanks


Ian


none
 
Posts: 3
Joined: Sun Mar 02, 2003 9:58 am
First Name: Ian
Last Name: Meikle

Response to Stirling 1

Postby info74 » Sun Mar 02, 2003 4:29 pm

I posted some general comments on how to generally trouble shoot any Stirling engine in a different thread. Perhaps we can find the author and get him to comment here on his engine.

Stirling engines don't need to have a displacer piston, all they need is a mechanism, it can be anything from two pistons to a displacer piston to acoustic waves, that moves the air back and forth from the cold side to the hot side.
info74
 
Posts: 70
Joined: Thu Aug 02, 2001 7:41 pm
First Name: Brent
Last Name: Van Arsdell

Response to Stirling 1

Postby none » Mon Mar 03, 2003 9:09 am

Brent,

Thanks for your comments, since this is a known design, and I know I don't have any air loss between the heater tube and the power piston, it must be the power piston that is letting too much air past. I have just bored out the cylinder again, and will be making a new piston soon. We will see how that goes.

It could also be that my linkage is not as smooth as it should be. The design in the book, and your comments, say that the linkage should be very free running. Being new to this, I find it difficult to quantify this. Without the heater tube attached, so no compression, if I spin my flyweel I get about 5 revolutions before the system comes to a halt. How does this sound ?

I was interested to read your comments about the requirements for a displacer. This of course makes sence. It was just that I have read in several places that the swept volumns of the displacer should be 1.5 times the swept volumn of the power piston for most "standard" Stirling engines. However without a displacer, is there any guide lines as to the ratio of the heater cylinder to power cylinder ?

Many thanks in advance
Ian
none
 
Posts: 3
Joined: Sun Mar 02, 2003 9:58 am
First Name: Ian
Last Name: Meikle

Response to Stirling 1

Postby stan.hornbaker » Sat Apr 05, 2003 6:37 pm

The booklet "Building Stirling 1" was obtained recently from Lindsay Pub. After studying the sketches, it is not really a book of plans per se, my conclusion was that it is more like the "ThermoAcoustic Hybrid Stirling Engine dsecribed by Bob Seir at URL "stirlingengines.org/thermo/lamina.html" See also "www.angelfire.com/ut2/texubaco/ for a TAHSE and a simple to make thermoacoustic laser with links to source of material and to other Stirling engines of novel configuration.
stan.hornbaker
 
Posts: 532
Joined: Thu Jun 20, 2002 6:01 pm
First Name: William S.
Last Name: Hornbaker

Response to Stirling 1

Postby stan.hornbaker » Sat Apr 05, 2003 7:56 pm

Correct the site for Bob Seir to "http://www.stirlingengines.org.uk/" and click on "Thermoacoustic and other forms of displacerless engines."

Are your engine components "loose enough?" Linkages should swing freely with NO binding, yet not be sloppy. To test a piston & cylinder let the piston (seal any axial holes first) drop vertically throught the cylinder. It should fall freely. Then seal or close off the bottom of the cylinder and the piston should fall very very slowly to the bottom indicating a good fit. If if fall fast make a new piston!
stan.hornbaker
 
Posts: 532
Joined: Thu Jun 20, 2002 6:01 pm
First Name: William S.
Last Name: Hornbaker

Response to Stirling 1

Postby none » Mon Apr 07, 2003 12:23 am

Hello All,

Thank you very much for the responces. It seems that it was that the cylinder pison fit that was too lose. I remade the pair and now the engine runs :o) I think there is still a little stiffness in the system, since I need a little spirit burner to run it where as I have seen that it should be possable to run them from a night-light (small candle), but at least it runs !
I will have to make another one now to see if I can make it better !!

Cheers for the help,

Ian
none
 
Posts: 3
Joined: Sun Mar 02, 2003 9:58 am
First Name: Ian
Last Name: Meikle


Return to Model Stirling Engines

Who is online

Users browsing this forum: No registered users and 2 guests

cron