Totally off thread but the picture reminds me of when I was sitting on a bench in Orchard Road having been thrown out of a bar with an R&R US Army Chinook pilot. The subject was the nostril intakes on the front pylon.
He told me, remember this is the 1970s so it was a Mk 1, that it was a pressure sensitive system to keep the aft rotor behind the front one. " The s##t hits the fan if you have a bird jam up one of them."
Is that what they were for? possibly overtaken by electronics.