Harrier Testing

[Cron]

In John Farley's lecture notes:

(John Farley's Lecture)

In the 'STOL flying section' regarding slow approaches he states: 'There were two possible controls of lift (wing and engine) and two of speed (RPM and nozzle angle)...'

I have re-read this section and phrase many times and are struggling to get understanding regarding the meaning of 'engine' and 'RPM'. I am seeing them as interchangable and suspect I am wrong.

If they are interchangable, then they are a common factor and thus I read the phrase as 'wing controls lift and nozzle angle controls speed' and thus I am seeing only one control of lift and one control of speed - engine running of course.

Put me right someone.

Many thanks

Cron.

[Um... lifting...]

I don't know... but would think that total lift on a Harrier is a function of wing lift (which itself is a function of wing AOA and speed) and vertical thrust vector (a function of nozzle angle(s) and RPM). Forward speed would seem to be a function of horizontal thrust vector direction (determined by nozzle angle) and magnitude (determined by total engine thrust or RPM)

I think in your standard lift-weight-thrust-drag model, if you were to substitute the word 'thrust' for 'engine' in the first one and 'throttle setting' for 'RPM' in the second, that may be of some help in developing your mental construct.

[unstable load]

It could be the wing in flight and (engine derived) thrust vectoring in the low speed/hover regime.
In low speed/hover then the RPM of the engine plays a part as the amount of vectored thrust is a direct function of engine RPM and the angle of the vectoring nozzles.

[Um... lifting...]

In that particular paragraph Cron cites, Farley's discussing transitioning to slow-speed landing handling, so I'd say you've got it in one, unstable load.

[Hilico]

And just for confirmation, you could ask him.

Doesn't he post on here?