Originally Posted by
FastDEW
Hi, I have a question that I have been thinking about for a while now. It seems that whenever I am on an A320 the wing seems to go clean (flaps/slats in) very quickly on take off and also seems to stay clean until just before landing. I notice the 737 seems to clean up much later on climb than the A320 and also seems to extend much sooner on slowing for landing that the 320 does.
Is this my imagination or is there something to this? Why does the 320 wing seem to get clean so much faster than the 737 and stay clean so much later?
Thanks!
Neither airplane is good at slowing down rapidly like the old 727 or MD-80. And the boards are not as effective.
I've been off both for a while now but.. the 'bus has flap settings called 'config' 0, 1, 2, 3 and 4. The actual flap angles vary but it doesn't matter. We took off most often in config 1 or 2. And you clean up according to computed data. Most often you are clean before 200kts.
On the old 737-300/400, you had flaps UP, 1, 2, 5, 10, 15, 25, 30 and 40. Most takeoff were 5 or 15. If you did a flaps 1 it was due to some performance problem. 1 was essentially a little trailing edge flap and leading edge much like config 1 on the 'bus. Most landings were 30deg with the 40 eventually being locked out. Landing in the bus is config4 except with gusty winds and windshear and you may want config 3.
Flaps on the 737 came out anywhere from 230 down to around 210 according to weight for flaps 1, 190 for flaps 5, 170 for flaps 10/15.
On the Boeings I flew, the magic numbers were 210 and 140. If you lost an engine and could get clean and 210, you were home free. And 140 worked as a rule of thumb for final approach.
The other old rule was in Boeings, you had to slow to extend flaps. Initial flap speed on the MD-80 was 280kts for initial slats.