What are these engines on a DC-3?

[Proplinerman]

Here is a close up shot of one of the engines on preserved DC-3 I-RAGF, at the Volandia museum next to Malpensa airport, which museum I visited on 4th July:

DSC_0043 | Flickr - Photo Sharing!

I've seen a very large no of DC-3s over the years, but this stack exhaust system was, I think, unlike any other exhaust I have seen on a DC-3. And also, the cowlings seem unusually close-fitting.

I think that, when I was at the museum, I read something about the Super Constellation Flyers' Association of Switzerland having supplied the engines for the aircraft's last flight (from Perugia to Malpensa,) on 5th May this year, if that's any help.

So, can anyone id these engines please?

[barit1]

Can't say for sure - But this MAY be part of Ben Howard's DC-3 optimizer kit. Benny was a remarkable backyard aerodynamicist, and worked with Douglas in 1937 during the initial R-1830 installation for UAL ships. He was never too happy with the cooling system drag - and postwar he developed the aftermarket optimizer kit (exhaust system, closer cowl, and I believe smaller wing root fairings)

I'm sure 411A would have known more detail.

[TURIN]

Just guessing here.

Is it anything to do with reducing exhaust flash. I know some a/c had problems with pilot night vision issues due to this.

[ATL-98]

Looks like it has the cowlings for the maximizer kit by AiResearch.

The mod had new cowling, baffles, oil cooler duct and exhaust system.

Old photos show it also had the gear doors when in South Africa as ZS-DJZ.

[bluecode]

The cowlings ring a bell. Here's a pic of N4565L. Note the cowlings and the undercarriage doors. The exhausts are different though.





Further digging revealed this on Ebay of all places. Think that answers the question fully.

[Proplinerman]

Thanks for all the replies-problem solved. Presumably it lost the undercarriage doors somewhere along the way.

[MarkerInbound]

With the doors there was a 126 knot gear speed, not that you'd see much more than that in cruise. But the oil cooler doesn't match. And I've seen the exhaust before. Most Threes used exhaust air for cabin heat so they had long exhaust pipes. Some had combustion heaters so they didn't need the heat exchangers and used short stacks. They must have picked up the cowls somewhere.

So you can buy a Maximizer Kit on eBay?

[Round Engine]

ZS-DJZ

Indeed, this aircraft (s/n 26244) DID have the full maximiser kit installed years ago as ZS-DJZ and it previously wore the matching -94 engines (as did its sister ship ZS-DIW), which is still flying, albeit also with a diluted form of the same kit and now -92 engines - here are some photographs;

Douglas DC-3 C-47 C/N 26244 ZS-DJZ