Speed Vref?

[jrpilot]

whenever I am flying the PMDG 737 I always get told to select a speed ref...I know where it is at on the panel but which one should I select?


Also when taking off do I put in my V2 speed on the MCP or do I put in V2+20 on the MCP...

Thanks

[Nexus]

Approach vref is selected on the INIT page of the FMC. Depending on the landing flaps cpnfig, speed will vary.

And always set V2 prior to takeoff  :)

[jrpilot]

Thanks


Sometimes when I take off though my takeoff speed will be  140 with flaps (5) for example...but when landing with flaps 25 (I think it is 25 it is the second notch from the last on flaps) the landing speed will be 140+ which makes no sense since I just flew a 1000 mi flight (not sure in km)  Ithought it would be lower than that but then again befdore this I never selected a VREF  :P

[Nexus]

You have a higher stall speed during takeoff, compared to during the approach (difference around 15-20kts),

Vref is the stallspeed x 1.3
whereas
V2 is the SINGLE engine TAKEOFF safety speed, therefore to able to meet all the criterias in the various climb segments, the speed has to be quite low so the aircraft can gain as much height as possible. Still within a good margin from stallspeed though.

But you (hopefully ) have 2 operating engines so you climb like a rocket  8)