Apologies for the length of post
For those who are interested in correct Harrier information please read (slowly) on.
If you divide the current service max STO weight by the aircraft empty weight the number you get is 1.93 to 1.98 depending on the individual aircraft mod state. Work is ongoing to increase this into the range 2.06 to 2.1
For any fast jet to have a payload equal to its empty weight is very good (as this is the sort of fraction airliner designers aim at) but when it is a fast jet that also contains a bunch of kit to enable it to offer the operating site flexibility that stems from a VL then it becomes quite remarkable.
I do appreciate that when I delivered the early aircraft to the RAF in 1969 things were not so good as today, but even then I used to fill it with fuel, do a VTO and fly for 75 mins to a German base. The payload fraction on STO in those days was closer to 1.7.
Since then (38 years ago) things have moved steadily on with four major engine upgrades to the UK fleet. Indeed the latest engine to go into UK Harriers has 3000lb more thrust at ISA +35 (yes that is 50deg C) than the engine it replaced.
Despite these facts people are still writing here about ‘its awful payload’.
The Harrier’s extreme hovering inefficiency in terms of power used does not matter when the total time it is needed to be used during a landing is less than a minute. The total weight of fuel used in this process is between 100 and 200lb depending on the time the pilot chooses to spend flying below wingborne speeds (partially jetborne) before coming to the hover
The Harriers job (that is to say the military role it was designed to carry out) is to attack targets. It does not have a job to do in the hover except at airshows when various manoeuvres are used to entertain the crowd (plus demonstrate to those in the business the considerable margins of handling and control that exist beyond those needed to carry out a routine VL at the end of a sortie). At such times efficiency is of no concern.
It is true that the Harrier could fire some of its armament options from the hover and might in very limited circumstances improve aiming accuracy by so doing. However unless the target was a hospital or unarmed women and children queuing for soup I think most pilots would prefer to be flying a high speed during an attack. It is also true that the Harrier is the only fast jet in service anywhere where the pilot can retreat while facing the enemy, but I do not believe this has been a factor in any procurement decision to date.
Why do we need helicopters when we have fast jets that can hover?
Because we have the need to do jobs in the hover that often involve considerable time and so must use a much more efficient system to provide the necessary lift. Such work in the hover also requires the most benign possible conditions under the hovering device and jet lift necessarily involves the opposite with high exhaust gas velocities and temperatures.