advantages of slow-speed performance
High-performance fighters have one of three wing shapes- trapezoidal (leading edge sweeps back, trailing edge sweeps forward), sweptback (with low aspect ratio & both leading and trailing edges sweep back) & delta. The former two designed primarily for high-speed flight have relatively poor low-speed characteristics- the first consequence of poor lift at low speeds is a higher stall speed (minimum speed an aeroplane must fly to produce lift or else fall to earth). If stall speed is high the plane is forced to fly faster than that (irrespective of mission), burn more fuel increasing the cost of flying it.
The second consequence is how lift & drag vary at low speeds- you need to understand the low-speed flight regime, the region of reverse command & power curve explained here beautifully-
There are three regions in the power curve and airspeed control is king
1. Region of reverse command- We have a lot of drag on the airplane at lower airspeeds (high AoA having to plough through air) which is the back side of the power curve. Speed increases, drag reduces.
2. Minimum drag- When you want to go far this provides maximum endurance- any slower or faster you have more drag.
3. Front side of the power curve- Step on the gas, speed increases, drag increases until you reach top speed.
Good low speed handling is important- every plane operates there, intentionally, at least twice every flight- during take-off and landing. Delta wings can produce a lot of additional lift at low-speeds (when placed in a high angle of attack, thanks to leading-edge vortices)- affording better handling characteristics in the region of reverse command.
When you are coming in for approach, you are aiming for minimum drag- if you are slower then you have to add power as you are fighting higher drag. If perchance you are dangerously slow, then you have substantially more drag. To get rid of this drag you need to speed up, by losing altitude. Only then you will have engine power available to climb away from the ground. Now imagine you are at 20 feet and you have to go down to go up because of being on the wrong side of the power curve- but you don't have enough altitude to lose to gain speed!
Having both safety margin of lift and higher control at low speeds are a boon for landing on aircraft carriers as it allows precise manoeuvring to trap the plane. It has benefits for land based planes too as it can operate from shorter runways- does not need to build up higher speeds to create lift & take off. Also on landing it can come in slow reducing stress on the airframe, wear & tear on landing gear giving it higher life and since the speed was low, to begin with- can come to a stop at a smaller distance. That's a win-win!
.. The Mohammad Ali plane!
which year is the announcer living in !!!
