This is not a real Thing that you'd want to bother with. It's just a conceptual test of an oddball idea. It seems to work, but that's with the odd configuration of my printer which is probably completely different from anyone else's old Replicator. It was made to use some of the stuff I had on hand, which again, certainly won't match the stuff you have on hand.
Anyway, it's here just to add to the community knowledge - I've given it a try so you don't have to, should you have the urge. OTOH, it does work... so some deranged individual might want to try something similar.
So I had this centrifugal blower fan on hand. It's much larger than fans typically used for print coolers, with those fans always being mounted on the carriage. I also happened to have a CPAP mask hose. [FYI a CPAP is one of those breathing machines that people with sleep apnia use to prevent snoring (and death)] The CPAP hose is lightweight, very flexible, and smooth inside for unimpeded airflow. It also has a nice pliable rubber connector on one end, and the other end is a neet plastic swivel. So, why not a blower mounted on the back of the printer, and a flex hose to the print cooling duct on the carriage?
My replicator is a dual extruder version, but I only have the right extruder mounted. The duct I have here won't work with both extruders mounted, but a duct could be worked out to accommodate both if necessary. This duct mounts with one of the tall center carriage screws, and also supplies a cable mounting point. There's also another screw location that just supplies a friction point so the duct doesn't swivel. It would be simpler to mount the duct to the cold bar with the left extruder mounting holes, but I usually had the left fan mounted there for extra cold bar cooling. The swivel end of the CPAP hose just friction fits into the duct, and that's all it needs - it stays in place nicely even with the carriage in motion.
Note that this is a CPAP mask hose, not the main hose. It's much smaller than the main hose and is a perfect length. Don't have a hose? Ask around. Lots of people use CPAP's, and the hoses are usually replaced every six months or so.
The fan mount just slips onto the top plate at the back of the printer and is secured with a single screw. The fan just screws onto the mount. The fan-hose adapter is just a slip fit on the fan, and the rubber end of the hose is just a slip fit too. It all stays in place nicely. I have a large acrylic hood that fits over the entire top of the printer, so the hose, fan, and the fan mount are entirely enclosed in the heated chamber.
The hose just needs a single zip tie to the carriage cables. It follows along nicely with little to no extra force on the carriage, and doesn't interfere with anything in the chamber.
The blower I had was 12V, which wasn't a problem for me as I have a 12V supply mounted in the base of the printer (along with a 24V supply). I run the 12V thru a cheap speed control so I can adjust the airflow down. Holding it up to my face it feels like a pretty good breeze, so I know I've got some fiddling to do to find the flow necessary.
It's manual now of course, so I need to see what's available for g-code control. I seem to recall that the MightyBoard isn't too swift in that respect.
The duct is really clunky and needs rework both in both the airflow and mounting aspects. It does approximately direct the airflow towards the print just below the nozzle, but I'm sure it could be better.