Found something interesting via other forums (rennlist and rennteam).
One idea is that they use the already existing roof mechanics from the cabs for the targa roof. That might require lifting the rear window slightly in the process. Rennlist member ISUK made a sketch illustrate the process. It can be found here.
There's also a patent from dec 2011 that shows a similar idea.

Can be found here.

It should be interesting to see exactly how it looks and works when the car will unveiled.

 

I rarely to never say that about a Porsche, but the Targa looks rather ugly :-(

 

Takes a special person to want one of these. I'm not that guy.

 

I don't like the look of it. Looks very retro, and by that I mean it looks like an old model, not cool and funky.

 

Targa Patent Images Leaked:

Future Porsche 911 Targa 2014 : les images scoop ! - News Automoto 2013 - MYTF1

 

IMO it doesn't look right. Hard to explain just some models can pull this off, this model more specifically this years model can not and looks like a design mess,

 

A British member (ISUK) of Rennteam & Rennlist has come up with the best explanation of how the new 991 Targa roof mechanism might work after I asked the same question on the Rennteam forum several years ago. This is his latest post on the subject at Rennlist:

"I posted this on Rennteam over a year ago now and I think it was copied here on another thread in the 991 section about the targa earlier this year.

The 'targa' panel section is already on the cabrio. Underneath the fabric cover is a hard composite roof panel. From the drawings it appears that the top of the roof bar telescopes upwards to let the targa panel slide beneath it then retract rearwards to stow under the clam behind the rear seats as it does on the cabrio. The roof bar will then presumably close back down leaving the original roll hoop look. The parts of the roll bar that appear to remain attached to the rear glass are likely just the decorative side panels that hide the hydraulic mechanism, that allows the top of the bar to lift up and down, when the roof cycle of opening or closing is completed.

It should be quite a cost effective system to engineer as it appears to use the same Z frame roof scissor frame section and same rear clam opening mechanism as the cabrio. Presumably the rear glass window will have to be made from fairly lightweight material (polycarbonate perhaps?). The lifting targa roof bar is the new and more complex part of the design. I've done a quick sketch to show this movement."

Personally, I don't think the rear glass window will be made of a polycarbonate since that might not meet US DOT approval and it needs to be sold on this market to make it a success. That is why our previous US spec 997 gt3 RS did not come with the lightweight rear Plexiglass window that the ROW got on theirs!

Saludos,
Eduardo
Carmel

 

The new car will debut this January at NIAS but look at these guys seemingly pissed at the spy photogs!