Linear Oscillating Generator

[toto]

Hi every body.

I hope I'm not posting to the wrong forum/topic.
I've been reading most of the posts on this Special coils forum and other related forums but you guys are just too technical for me.
I'm currently developing ? oscillating free piston stirling motor and would like the piston to act as an electrical generator.
Basically the piston could hold a permanent magnet or a coil and oscillate in a (coil or magnet) cylinder.
I will share all the plans when finished with building and testing. That's a promise.
Unfortunately I don't know much about coils and electrical generators and there is very few information on the Internet about such Linear Electrical Generators. 
Can you inform me (even partially) on those certainly very basic questions:

1- What's the most efficient solution: magnet piston with coil cylinder,  or coil piston with magnet cylinder? (I was thinking of using cylindrical shape magnets)

2- How can I calculate the wire thickness needed, number of winds on the coil and the electrical power output produced by such linear generator? (given strength of the piston, displacement speed and length, number of oscillations per minutes etc..).

3- I've discovered on this forum that different types of coils windings exist. Which one would be the most efficient in this case?

4- Is there a way to avoid the Lenz effect on a linear generator?

5- From my research on the Internet I'm aware of the loss of efficiency of permanent magnets as the temp gets higher.  What's the Highest temp a magnet can handle without loosing it's magnetism?

6- Is it possible to use multiple magnets side by side to build the cylinder or the piston.

7- What is the big question I should have asked but didn't because I don't know anything about coil generators.

I realize this is a lot of questions.  I hope there's room for newbies. If not. Sorry for disturbing your highly technical discussions.
Excuse my poor English.

[penguin hood]

Hi Toto

Question 1:
The coil piston will need brushes, then fiction. The other arrangement (coil cylinder) can be brusheless.

Question 3:
Nikola Tesla said that the bifilar coil produce more voltage and store more energy than a solenoid coil from similar characteristics. Unfortunately still no evidence about this in the accepted theory.

Question 4:
According to the classical electromagnetism, it is impossible avoid the Lenz Law.
However also Nikola Tesla was the first to say that back-torque may be artfully reduced to much less than a classically-figured level on a Faraday disk machine. It is still debated such possibility. The disk Faraday was the first electric generator but was replaced by the alternating current system we use today invented by Tesla.

Question 6:
This magnet array is very interesting, perhaps it is useful for you:
http://en.wikipedia.org/wiki/Halbach_Array
http://www.matchrockets.com/ether/halbach.html

Later I post here a diagram from my idea about a linear generator using Halbach arrays...

[jake]

Question 2
1) "cut and try" - guess reasonable starting points and work from there
2) Study known generator theory and calculate everything.  This will get you closer starting points if your input assumptions are correct.

Question 5 - It would vary with the magnet material, etc.  I know that neo's lose it at a relatively low temperature compared to many other materials.  I think the number is below 200F for neo's - maybe as low as 170F to 190F.

[penguin hood]

Toto,
Below the diagram that I did mention before.

The red square inside the two parallel halbach arrays is one coil.
Two options to generate electromotive force:
- To move the coil at right-left direction while halbach arrays remains fixed.
- To move the halbach arrays at right-left direction while the coil remains fixed.

The first option needs two rails werein the coil brushes lies to collect the electricity generated.
The second option is brushless but the magnets are more heavy than the coil.

The reason to use halbach arrays is that augments the magnetic field on one side. It is important to concentrate all magnetic flux where the coil core pass. The coil should have a ferromagnetic core and the turns can have square shape to fit better with the magnetic field from square shape magnets.