Yes, this was the thread
Thanks

Speaking of the fan drive system, check out page 13.

I was looking at that and can't see how the whole thing is driven.

Cheers Rob.

Driveshafts come off the left and right sides of the overdrive unit just below the air compressor that drive the fans,

There is still some linkage not shown.

Cheers Rob.

Admittedly you have to study the photos closely on pages 12, 13 & 14 of the website covering the paper model. Eventually you will see that two driveshafts come out the left and right sides of the overdrive unit. These go to gearboxes in the right and left rear corners of the engine sheet metal enclosure. From there two more driveshafts go forward to gearboxes in between the fans. These final gearboxes run the drive belts that actually turn the fans.

Here is a somewhat rough composite I made from an exploded drawing I found in the manual.



Top center pulley between fans is an idler pulley. Tightening jack screw #7 allows you to raise the idler pulley and thereby adjust out any slack in the fan belts.

Cheers Rob.

I think the differences are strictly sheet metal as has already been stated.

I believe on later models this mechanical fan drive system was replaced with a fluid (hydraulic) drive system.

A very nice build of that rear engine speed reducer and fan drive posted elsewhere by enrico63:

https://www.modellismopiu.net/m+gallerie/main.php?g2_view=core.DownloadItem&g2_itemId=874130

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