RE: Ziroli DC-3
All depends.If you have lots of power and lots of runway with no need for a steep climbout you don't need them,otherwise I'd use a little flap.It also gives it a more scale like look when its flying a bit slower with flap.I've seen DC3's flying way too fast for scale.if you see a full scale flying it appears like its hardly moving up there.Its flying around 100-120 knots but it sure doesn't look it from the ground.I think everyone is worried about tip stalls so they fly em fast with flaps up.
I tip stalled mine at about 100'-150' on awindy downwind leg once.I had the power back and was just doing an overhead flyby with flaps down.As I got towards the north end of the field I retracted my flaps,I noticed a bit of a wing drop and before I new it I was in a full stall.I immediatly dropped my flaps as it went into the first turn of a spin,applied opposite rudder,got it straight,and it flew out of the stall/spin loosing only around 50-75' maybe.Right after that I landed without incident.I learned a lot on that flight needless to say.So you have to be aware of your speeds,don't pull it off on takeoff let it flyoff with or without flap,and keep your banking angles low and you'll have no problems.
Steve