Correct me if I'm wrong but regardless of whether the circuit is designed for noise abatement or not, each aerodrome has a circuit pattern which pilots should adhere to.
News to me. The AIP indicates circuit heights and directions, but often, perhaps usually, nothing more. I've seen nothing that specifies how wide a downwind leg should be flown or how far it should extend, except in some very special cases.
It's simply not possible to have a one-size-fits-all circuit, which is why, for all the whining here and elsewhere, a recommendation of a specific distance is not published in the AIP, or the AIM, or anywhere else with any authority. I share a circuit with aircraft whose normal cruise speed is below my Vmca, as well as those whom I don't want to get within three minutes of for fear of what their wake will do to me. Many aircraft beyond the scope of the primary trainer don't appreciate having the power shoved on full for take-off and then yanked all the way off for a glide approach minutes later.
FFF wrote:
I have always been a little baffled by the zealousness with which some people talk about flying tight circuits.
Seems to be a macho thing: "Mine's tighter than yours."
Yes, teach students to fly sensible circuits consistent with the aircraft they're flying, but let's show a little tolerance for the diversity of needs in aviation and not get carried away with this. It's not a way of scoring points over other pilots.