OK Here we go. Its too windy to fly my toy aerplane so I fiddled and got this.
The force BC is what it is all about. If BC acts ahead of the CG it will make the aircraft unstable and the drift angle will increase (bad) but if it is behind the CG it will reduce the drift angle (good).
If the wheel in the diagram is a tailwheel AND IT CANNOT CASTOR (ie is locked) it will be good news and stabilse the aircraft. If it CAN castor it will be swung round by BC and so not help.
http://content.communities.msn.co.uk/isapi/fetch.dll?act ion=show_photo&id_community=EggSucking&id_topic=2&id_message =1
How was that for you - as they say
[This message has been edited by John Farley (edited 30 October 2000).]