Originally posted by Galahad 
I too do not get flaps.  I know when you go up and get slower to engage the flaps.  What I don't understand is when to deploy them.  Is this done by feel?.....someone has told me to deploy them at certain speeds,,,,I find this suggestion to be very impractical in a fight.  I watched the film by Widewing and saw he deployed his flaps (about three notches)....I usually fly the J model and not the G,,,,,does this make a difference?  Also when do you retract your flaps ...I know that when you are going  down/faster to pull them in but precisely at what point?.... or do you just use the auto retract feature?  
Galahad:confused: 
 Like Murdr said, it's basically by "feel" that you develop over time. But there is a guideline that you can use that will give you an idea.  This was taught to me a long time ago by a really good P-38J driver in AW named Stnky.
[All speeds are in Indicated Air Speed]
250mph - 1 notch
200mph - 2 notches
175-150mph - 3 notches
150-100mph 4 notches
below 100mph - full flaps
Use this as a guideline and as you get more experienced in the P-38, you'll notice that you'll start to develop a feel when to deploy and retract the flaps.  I never let the auto-retracting feature to retract my flaps for me.  If you rely on the auto-retracting flaps to retract the flaps for you, you're just asking for a boatload of trouble to come smack you in the head.  There is a very real risk of entering into a near uncontrollable spin caused by the flaps auto-retracting while in a turn fight.  It's nasty and you don't want to experience it.  It is also highly unrealistic but HT had made up his mind about keeping the auto-retracting flaps.
I highly recommend that you visit the 
479th Fighter Group's website and read Murdr's excellent series called "PJ University".  Originally written for the P-38J in Air Warrior, Murdr has already converted most of it to reflect the P-38s in AH.  A must read for any P-38 driver, greenhorn and veteran alike.  Also make sure to check out the film library as this is probably the biggest collection of P-38 specific films for AH.
Ack-Ack
479th FG.