Thanks.It would appear that the one at 12 o'clock is an air intake (carb?).
I have no idea of what the pointy thimble thing at 1 o'clock (facing forward).
Other pictures show two pointy thimble things at 1 and 11 o'clock and no 12 o'clock 'scoop' and other photos show all three.
View attachment 837697
Some of the early Dutch built ones had Wright Cyclone R-1820 engines.
Some got BMW 132N radials and over 1/2 of the production got BMW Bramo 323R-2 Fafnir radials.
The things at 1 and 11 o'clock could very well be exhaust outlets, keeping then out of the spray.
The different engines may have required different carb intakes?
The presence of a central air intake flanked by two exhausts stacks seems logical, especially as the carburetor inlet had to be kept away from water spray. This assumes an engine with an inverted (downdraught) carburetor, but this wasn't the case for all engine models fitted to this aircraft—the Bramo had an updraught carburetor.
And I also wonder about the absence of exhaust dirt on the cowlings !