Harrier transition to and from hover

[lifts a gift]

IMD

IMD, well explained by BS is not in itself a problem. It just makes the jet go sideways. The problem is that swept wings producing lift do not like to go sideways. The into wind wing loses sweep and Cl increases. The downwind wing has its effective sweep increased (and is shielded somewhat by the fuselage) and therefore loses lift. Result mega, rapid, uncontrollabe rolling moment. Not good during VSTOL.

The rolling moment depends on a) IAS b)alpha c) sideslip. Any one of these zero - no probs (no lift). Either b or c large and the other two small big probs.

Given that one must accel/decel through the 30-90 kt band where the jet is directionally unstable, and that to lift a war load wing lift is needed at these speeds b and or c must be minimised.

In my day in the GR1-3 8 to 10 units of alpha was reasonable 12 a bit gamey.

Sideslip is minimised by 1) Yaw autostabs 2)Rudder pedal shakers 3) HUD sideforce symbology and 4) THE VANE

Early signs of things going wrong are a lateral stick displacement to keep wings level. This is quite attention grabbing and the recovery actions are simultaneously 1. Rudder to get the vane straight. 2.Full pwr through the limiters to increase pwr of the 'puffers' and inc vertical lift thereby reducing AoA. 3. Stick fwd to reduce AoA. 4.Change trousers.

Hope this is of use. For all a/c but particularly the Bona-Jet

Lifts a Gift. But thrusts a MUST