|Quoting fr8mech (Reply 2):|
On the -7X series aircraft, they are the ram air inlets for the packs. On the other models that are the inlets for the turbo-compressors.
A few previous threads on same subject probably have some further details.
DC-8, DC-10, L-1011 Nose "Air Intake"? (by Mr Spaceman May 22 2001 in Tech Ops)
Douglas DC-8 Inlets On Nose (by HAWK21M Dec 14 2004 in Tech Ops)
Question On Nose Intakes On Douglas DC-8 (by LTU932 Mar 28 2007 in Tech Ops)
RE: What Are The DC8's Large Nose Air Intakes For? (by Broke Aug 6 2003 in Tech Ops)
RE: UPS DC-8 Nose Inlets (by Pilotpip Feb 12 2004 in Tech Ops)
RE: DC-8 Nostrils (by Dtwclipper Sep 11 2004 in Tech Ops)
The turbocompressor inlets on the DC-8 nose (-10 through -60 series models) are equivalent to the inlets at the front of the engine pylons on 707s where the turbocmpressors are in the pylons of engines 2/3/4. The 720 only has 2 turbocmpressors above engines 2 and 3. AA
also ordered their 707s with only 2 turbocompressors, thus the narrow pylon on engine #4 on AA
707s. I believe a very few other 707s may have been built with only 2 turbocompressors.
707s with the usual 3 turbocompressors on engines 2/3/4 and the narrow pylon on #1.
707s with the missing turbocompressor on engine #4.