toy alpha engine

Discussion on Stirling or "hot air" engines (all types)
cbstirling2
Posts: 117
Joined: Sat Dec 17, 2016 9:35 pm

Re: toy alpha engine

Postby cbstirling2 » Mon Mar 06, 2017 6:37 pm

Its interesting comparing the stats on the one pictured above (http://www.ebay.com/itm/New-Hot-Air-Sti ... 2230808015) with another alpha from Japan (http://global.rakuten.com/en/store/over ... -se-905hp/)
I think the one above might have naively chosen 90 degrees as the phase, as we know 90 isn't necessarily optimal. Its surprising to me that the phase angle is 120 degrees for the one from Japan, but clearly that designer did testing as evidenced by the youtube videos (https://youtu.be/mUzz2pPw2Pg https://www.youtube.com/watch?v=-8G4GgryJZQ).

The one pictured above from China:

Speed : up to 1700RPM
Generator Output: 5V appro.
Flywheel Size: 60mm(dia.)
Driver-wheel Size: 25mm(dia.)
Power Cylinder: 12.5mm (inner dia.)
Displacer Distance: 13mm (its not a displacer, but rather the hot piston...)
Dimension: 155(L) x 80(W) x 130(H) mm
Materials : Aluminum Alloy + Stainless Steel + Brass + Pyrex Glass
Net Weight : 700g
Phase Angle: looks to be 90 degrees

The one from Japan:

Stirling engine and SE905 series specification
Stroke 11 mm (Ross York mechanism)
Piston diameter 18 mm
Stage area 2.8 cc expansion and compression side 2.8 cc
Maximum rotation speed SE 905: 3000 rpm, shaft output 0.6 W
SE 905HP:3500rpm, shaft output 1 W
Phase angle 120 degrees
Gas temperature High temperature 500 ° c, low temperature side at 50 ° c
Remarks High grade miniature bearings use 8
CBStirling2

cbstirling2
Posts: 117
Joined: Sat Dec 17, 2016 9:35 pm

Re: toy alpha engine

Postby cbstirling2 » Mon Mar 06, 2017 7:09 pm

A chart from Martini's NASA report
Screenshot_2017-01-08-12-13-28.png
Screenshot_2017-01-08-12-13-28.png (314.18 KiB) Viewed 643 times

CC Lloyd "A Low Temperature Differential Stirling Engine for Power Generation" https://ir.canterbury.ac.nz/bitstream/h ... sequence=1
Martini, W. R. "Stirling engine design manual, 2nd edition"
https://ntrs.nasa.gov/archive/nasa/casi ... 022057.pdf
CBStirling2

Ian S C
Posts: 1981
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: toy alpha engine

Postby Ian S C » Tue Mar 07, 2017 1:16 am

That 10 kW difference is quite a bit isn't it.
I think my Ross Yoke motor has a phase angle of just a bit over 100*.
Ian S C


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