Putting a duct in to exhaust an electric dryer through the crawl to the outside.
The total length of the 4" galvanized duct, from where it enters the crawl space to where it exits the outside wall, will be about 10 to 12 feet, with one sharp 45 degree turn and two more gradual 90 degree turns.
At the outside wall, is it better to use a straight piece of duct, with a slight downward slope all the way out through the outer wall - or - put an adjustable 'corner' section at the hole to the outside and feed it with a shorter but more downwardly sloped straight piece?
The hole to the outside will be in the same location, either way. The straight section will be about 6 feet long. The total drop on that 6 foot length will be about 3 inches.
My guess is straight all the way to avoid extra lint-trapping by the adjustable corner at the end that goes through the outside wall.