This angle is called the
climb gradient, and you can find it using instrument approach charts.
According to Chapter 5, Section 2, Instrument Departure Procedures, there's guaranteed obstacle clearance when "crossing the departure end of the runway at least 35 feet above the departure end of runway elevation, climbing to 400 feet above the departure end of runway elevation before making the initial turn, and maintaining a minimum
climb gradient of 200 feet per nautical mile" unless otherwise specified.
After the project was revived by the present government, NAL incorporated design modifications and improvements on the SARAS PT 1 model, like 2x1200 shp engines and 104-inch diameter propeller assembles to cater to second segment
climb gradient requirements, improved flight control system, rudder area, main wheel and brakes to cater to 7100 kg AUV, indigenously developed stall warning system, etc.
The aircraft with higher bypass ratio engine needs more engine takeoff thrust to meet the takeoff filed length and engine-out
climb gradient requirements, which leads to increment in the aircraft weight and a higher DOC.
The FAA on November 19, 2018, issued new operating guidance to pilots and operators of Part 25-certificated turbine-powered airplanes intended to help determine compliance with
climb gradient requirements published in standard instrument departures (SIDs), obstacle departure procedures (ODPs), diverse vector areas (DVAs) and missed approach procedures.
An ATC-required altitude restriction published at a fix will not have an associated
climb gradient published with that restriction.
Runway 9 requires just over twice the normal
climb gradient all the way to 6000 feet.
A VCOA is a departure option developed when obstacles farther than three sm from the airport require a
climb gradient greater than 200 feet per nm.
It could be that you cannot comply with a DP, perhaps due to a steeper
climb gradient than you can manage, or to an altitude beyond your reach.
The initial climb is extended a bit more than usual in order to allow for a standard
climb gradient when turning right (note that for turns other than to the right, a normal 400-foot turn is allowed).
Looking back at Beech Field's Runway 1 departure, it calls for a 500-foot ceiling and one mile visibility if the pilot climbs at the standard obstacle clearance
climb gradient of 152 feet per nm, in this case to 2000 feet msl.