PPRuNe Forums - View Single Post - Harrier transition to and from hover
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Old 3rd May 2010, 08:37
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NigelOnDraft
 
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I assume water is sprayed into the compressor to increase the effective volume of air moving through the engine and also cool the engine
Direct into the turnine area IIRC... Basically reduces JPT, allowing more fuel / thrust / RPM keeping within the (now higher) JPT limits.

I understand the Pegasus can only be run at full hover thrust for around a minute at any one time?)
There's a big table of limits... but the top rating is for 15s only (and flashing lights to warn you!)

Also, I note there's a yaw vane in front of the cockpit.
I assume this is to ensure that hover transitions take place into the wind to prevent the jet weathercocking - rolling over
Yes - not necessarily "into wind", you just keep it straight with rudder so the relative wind is fore/aft. If you don't the rudder pedals start shaking, the QFI in the back/on the radio shouts "Vane", and if you ignore all that Critical period is 30K-120K - again IIRC. Below 30K no probs

How is the vertical landing carried out? It looks rather crude from the outside, as if the pilot just chops the power at about 30ft.
Not really "chop" the power, but you do not "cushion" the landing - just keep the RoD on until impact then idle straight away, and nozzles aft. It has been known at this point for people to do this in the wrong order (no names ) which is great fun for any observers...

Or is the seemingly brutal drop deliberate in order to lessen the chance of instability in ground effect, or FOD ingestion?
Spot on

NoD
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