Tue Sep 21, 2021 10:14 pm
On the DC-8 -10 to -40, the buckets/ejectors were mounted on rails that slid behind the engine. By SOP (where I flew) they were extended with flap selection. This was for two reasons; one is for sound suppression, the other is that they had to be extended to be used, so they were armed on takeoff should a reject be necessary and there for landing.
Also remember that the DC-8 was not equipped with speed brakes. The reversers were authorized to be used in the air! To be used, the ejectors had to be extended first. If it was thought that might be necessary, the ejectors were extended.
In the picture you cite, they are extended. When not, they snug up behind the engine.