According to a 1989 interview, Rory liked to use flangers over chorus pedals. At that particular point of time, he was using the Boss BF-2.
I don’t use chorus – I prefer flanging (I use the BF-2).
Rory Gallagher A Question of Taste
There’s also a quote from him from the early 90s on the subject of flanger versus chorus, which is a bit confusing. Depending on how you read the sentence below, he either used flanger regularly and a chorus sparingly, or he used flanger sparingly, and chorus not at all.
I’ve got a Boss flanger, as opposed to a chorus, which I use sparingly, I use that only in “Shadow Play” and “Moon Child,” and one other song.
Guitar for the practicing musician, August 1991 issue.
However, “Shadow Play” and “Moon Child” both sound more like a flanger, and based on other quotes, it seems that he was indeed talking about a BF-2.
My last bit of equipment is a Boss Flanger, used very rarely to pad things out in a couple of places.
RAW Magazine November 1988
Listening to Rory at the ’82 Rockplast gig there is heavy flanger on Shadowplay, Bad Penny, and others. https://www.youtube.com/watch?v=nlEfyMoR49M
I’m thinking about buying all these petals. I mostly play metal, and got some great ideas now for getting that modern metal sound going:)