Set up the equations and see for yourself.
F=ma
F= Thrust – Drag in level flight in newtons
m = mass of aircraft in kg (using empty weight)
a = acceleration in metres per second
a = (T – D)/m
F-35A
Thrust: 43000lb ~ 191219N
Mass: 13300kg
Typhoon
Thrust: 40000lb ~ 177879N
Mass: 11000kg
F-16blk50
Thrust: 29000lb ~ 128962N
Mass: 8267kg
F/A-18C
Thrust: 35500lb ~ 157867N
Mass: 10400kg
With this data it is easy to come up with a fairly basic acceleration performance metric. Drag is the only unknown in the acceleration equation. Therefore in excel it is possible to produce a spreadsheet where for a given reference drag (the drag the reference aircraft experiences), a competitors drag can be solved for. This is of course assuming at the reference drag, both aircraft have the same acceleration ‘ability’. This can be done for a whole range of reference drags – from zero drag (when the aircraft is on the on the ground) up till its max speed condition – where total thrust = total drag. This can be graphed (see below) to help compare aircraft level flight acceleration.
http://imageshack.us/photo/my-images/405/unledbf.png/
In this graph I have compared, Typhoon (reference jet) to F-35, F-16blk50 and F/A-18C. Typhoon, being the reference aircraft at any drag state (horizontal axis) requires 100% of that drag for that given acceleration. Comparing F-35 to Typhoon at any given drag state the Typhoon is experiencing (on the horizontal axis), requires X % on the vertical axis of that drag (seen on the horizontal axis) to match the Typhoon for acceleration. Therefore if the Typhoon is undergoing 50,000N of drag (h-axis) – the F-35 needs to be flying with 74% of 50,000N drag to have equal acceleration to the Typhoon. This plot combined with ‘engineering judgement’ can help as a quantitative performance metric for comparing fighters. At 50,000N ~ 11000lb of drag – F-35/Typhoon requires about 11,000lb of thrust or 1/4 of the power available to them to fly straight and level. If the pilot of an F-35 or Typhoon at this condition spooled up to max thrust – do you think that in that instant the F-35 is experiencing 74% of the drag the Typhoon is? It needs to be experiencing this amount to achieve the same degree of acceleration as the Typhoon. Thats where you need to use your ‘engineering judgement’. At the same state, the F-16 needs to be flying with 66% of the drag of a Typhoon to hit the same acceleration factor. I would upload the spreadsheet but im not sure where to.
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