Originally posted by SirLoin
Third point....These are WW2 fighters,not PT 19 trainers.They have instabillity built into them that is managed with trim.
Not to be picky here but...
The PT-19 is extremely, exceptionally stable and incredibly forgiving. That is definitely a true statement. It is, without doubt, the best aircraft to train a student in that I have ever flown.
However, not ALL WW2 fighters have "instability built into them". In fact, I doubt any were
deliberately made inherently unstable. Rather, aerodynamic tradeoffs were made for performance requirements that resulted in some instability in some aircraft.
Moreover, I know you've read reports, accounts and stories of aircraft that were "excellent gun platforms" and so on. This is a comment primarily on stability. So, quite a few were obviously pretty stable and the pilots noted that.
Lastly, instability is NOT compensated for by pilot trim. I know I've said it before but TRIM is not a primary flight control. If instability is to be compensated for, one uses the PRIMARY flight controls.
By it's very nature, instability implies a continually changing somewhat random situation. Trim is used for exactly the OPPOSITE situation, ie: need for a prolonged control displacement in one direction to maintain a STABLE situation. For example, one would trim nose up in a prolonged climb to relieve pilot work load on holding the stick back. Or one would trim nose up on approach to compensate for a necessary pitch change caused by lowering the gear.