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!

 

B737 Pilots have lilliputian orchis

 

not an expert on either however it may have to do with how well or how not well either airplane speeds up or slows down?

might also just be how each one flies...probably has a lot to do with the aerodynamic design of the wing...

i dunno i'm an idiot so that's why i fly for a living...not design airplanes...

 

I am curious on this. I wondered if it were more about the wing design or the fact that the bus is FBW so the computer was more accurate in when to retract and extend the flight surfaces. Anyway, guess I will just leave it to the experts that it all works and that is what matters most

 

Nothing to do with the computer on the bus. It is all controlled by the pilot and when they move the flap lever position up. I have flown the 320 but not a 37 so its hard to compare. I would say it has something to do with the common flap settings on TO. In the 320 you have Flaps 0, 1,2,3,full. Normally you use Flap 1 or 2 for T.O. In the 737 I believe that you have a few more and Im not sure what their profile is.

 

For takeoff, you would normally select Flaps 1, 2 or 3 . If you put the flap selector in the 1 position, it will give you 1+F (as shown on the EICAS).

The a/c will automatically retract the flaps at 210 KIAS if 1+F is selected.

1+F is only something done at takeoff, and it basically means slats at 18 degrees and flaps at 10 degrees. On approach/landing, placing the flaps selector in the 1 position gives you just the setting of 1 (slats at 18 degrees, flaps at 0 degrees)

 

The 737 has flaps settings of 0, 1, 2, 5, 10, 15, 25, 30, and 40. I believe most airlines use 15 degrees on take off and 30 degrees for landing. a few more notches that 0, 1, 2, 3, full.

 

I have never flown the 737, but I have sat up front quite a few times. I can tell you that they seem to configure on much the same schedule as we do in the bus. The one difference that I have noticed in riding in the back is this....the 737 flap system seems to make A LOT more noise than the bus. If you arent staring right at the flaps on the bus you wont even know they are moving. Combine that with the fact that the first "flap" setting on the bus is flap 1, but it actually only moves the slats to 18 degrees( I think), whereas the 737's first flap setting will actually move the flaps and cause a bit of noise and pitch change. The bus does have an extremely effective wing....I have trouble slowing it down all the time. Not sure how it compares to the 73 though.

 

Thanks for the futher replies. Since asking this question, I am now on the Bus. I have never flown the 737 but I really like flying the Bus a lot. I like the sidestick more than I thought.I only wish the throttles would move.....

 

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.