Originally Posted by
DH106
True - you & I would call them Krueger flaps after the way they deploy. Boeing seems to refer to them as 'slats' however if they maintain a small gap between themselves and the wing LE and thus function in the same way as a fully deployed slat - by accelerating air through the small gap. The 747 has what we'd call Krueger's full span, but I believe Boeing refers to them as Krueger's inboard and slats outboard.
Yes, you are quite right to point out that it's the rather curious method of deployment that defines them as Kruegers, rather than the configuration when extended. You wouldn't want them to get stuck half way out, although presumably they would blow back in the event of hydraulic failure in transit?
Perhaps the slotted Kruegers should be referred to as "Krueger slats"? I can't remember if part of the L/E Kruegers on the 707-320Cs were "slotted" or not. No doubt it makes sense to slot the outboard sections only, as you describe on the B747, to help ensure the outboard part of the wing doesn't stall first.
The 707-320C may have had rather old-fashioned L/E devices but, IIRC, its T/E flaps were double slotted, whereas the VC10's were single-slotted. And are the B747's mainly triple-slotted, except the 747SP?