Beta Stirling questions - please help

Moderator: stan.hornbaker

Forum rules
Be nice!
Post Reply
jonhjames___9698
Posts: 3
Joined: Sun Jul 30, 2006 7:49 pm
First Name: Jon
Last Name: James

Beta Stirling questions - please help

Post by jonhjames___9698 »

I am building a single cylinder beta type engine, but am having
trouble getting it to run. the bore and stroke of the power piston
and displacer is 5.5"B x 5"S. The engine has approx. 2:1
compression ratio, which makes it hard to turn over. I am using a
spoked aircompressor flywheel of about 15" dia x 2" thick at the
rim, which has a rim weight of about 23 lbs.

I have the displacer phase angle leading the power piston by 68 deg.
which I got from Merrick Lockwood's design (I don't really
understand why this is not 90 deg., but I just accepted it).

I heat the hot end to approx 1000 deg. F and water cool the cold
end. If I disconnect the displacer linkage and stroke it manually I
get about a 0 - 14 psi pressure fluctuation. For starting I turn
the machine to about 340 RPM with an electric motor. The machine
seems to want to run but won't quite take off on its own.

My biggest questions at this point are as follows are:
1. Might the flywheel be way too small?
2. Could the compression be too high?
3. What do you think about the phase angle of 68 vs. the usual 90
degrees.

Your thought will be greatly appreciated.

Jon James
jim.richards65
Posts: 1
Joined: Tue May 06, 2008 10:52 am
First Name: Jim
Last Name: Richards

Response to Beta Stirling questions - please help

Post by jim.richards65 »

To my eye, the most important information is missing. Gas volume, gas pressure, and to a lesser degree gas type. The behavior of expanding and contracting gas are mathematically defined by the "Ideal Gas Law" http://en.wikipedia.org/wiki/Gas_laws.

The "Ideal Gas Law" states that there is a relationship between gas volume, pressure & temperature. Since your Beta has heat (1000 DegF) I would be wondering about gas pressure?

If you're already building you probably already know this stuff, sorry for the obvious. Since the whole point is build working pressures I was wondering why none where given?

Good Luck!
Jim
Post Reply