Re: [Flightgear-devel] Harrier checkin

[AJ M. <aj-...@ad...>]

On Thursday 25 May 2006 12:30, Georg Vollnhals wrote:
> <!--
>   Harriers have little "reactor" jets to change the aircraft's
>       orientation during hover.  I've been unable to find a good
>       reference for where these are, exactly.  I've chosen to put the
>       pitch and yaw jets in the tail, and the roll jets point down from
>       the wingtips.  This makes logical sense, but I'd be pleased if
>       anyone can find better info.
> -->

"To cater for jet-borne flight, where the aerodynamic forces on the=20
conventional surfaces are reduced or eliminated, a system of air jet reacti=
on=20
control valves are utilised. These are placed in the extreme nose, tail and=
=20
at the wingtips to provide pitch, roll and yaw control. The system uses air=
=20
bled from the high-pressure compressor of the engine and the valves are=20
opened using pilot commands from his normal controls. Indeed, the valves at=
=20
the wingtips and in the tail are directly linked to the aileron, tailplane=
=20
and rudder so that when each of these surfaces moves its corresponding valv=
e=20
also opens. This occurs during both wing and jet-borne flight, but as the=20
engine bleed is only operative when the main engine nozzles are vectored=20
below 20 degrees no jet reaction force is produced unless the aircraft is=20
partially jet-borne. The interlinking of the aerodynamic and reaction=20
controls, allied to the progressive increase in the amount of air bled from=
=20
the engine with increasing nozzle vectoring above 20 degrees, ensures that=
=20
the aircraft is fully controllable at all airspeeds and during transition."

=46rom www.harrier.org.uk (/technical/Basic_TechNet.htm)

It's great to see a 3d model for the harrier in fg at long last - and a Sea=
=20
Harrier, too!  Stand by for some very odd looking flight profiles on=20
fgfs.i-net.h :-)

My only request at this stage is an easy one - that the aircraft starts off=
=20
with the parking brake engaged.  There are few things more irritating than=
=20
having the fg screen fade in only to find yourself pitching off the carrier=
=20
deck or into the nearest windsock!

Cheers,

AJ