When going to flaps 10, the Coeficient of lift increase is almost nil with respect to flaps 5, but the added drag is enormous. So you can descend at a steeper angle without a gain in airspeed, increase your ROD, but cannot fly slower than flaps 5.

 

 

Only siths and simmers deal in absolutes.

 

haha - that made my day...which is saying a lot as I've been in meetings all day with the day job.

I don't think anybody's arguing that extending flap does not increase drag. However, I can understand the point being made in the manual Vernon quoted from, which is that is is generally considered poor technique to be chucking the flaps out up near the placard speeds for the primary purpose of using the drag created to slow the aeroplane down.

 

This is on the basis that exposing the flaps to the higher aerodynamic loads caused by extending the flaps significantly above the manoeuvring speed for the weight/configuration on a routine basis will increase fatigue on the flaps themselves and flap system components.

 

Disclaimer: I'm not saying you can't do it, I'm not saying it doesn't work, just that as a standard way of flying the aeroplane it is considered poor form, at least amongst the airlines and pilots I'm familiar with over here. It might be different over in the States, I don't know!

I insist that you would really benefit if you can sign up for a real ground school course which does not cost much.

 

Excuse me? Well you can take that comment to the chief of aviation who i got that quote from

 

 

Well you can take that comment to the chief of aviation who i got that quote from

 

Quite honestly, the quote is more incorrect than correct.

Quite honestly, the quote is more incorrect than correct.

 

Well Flaps are to enable slower flight so i gather. I suppose you have flown in real life and took ground studies.

 

And simons post is a valid one though...

Often if you see speedbrakes deployed in flight, it isn't always because the airplane is having trouble slowing down. The pilots are complying with a request or making it easier on atc by descending at max rate possible. But as some 738 pilots have noted that model can have trouble descending at a good rate. The 77X has this issue when lightly loaded I remember by chance hearing over JFK atc the approach controller getting very annoyed that the Air France Cargo pilots were descending at a low rate after a quick hop from ORD.  - David Lee

 

 

Well Flaps are to enable slower flight so i gather.

 

Flaps are to increase lift up to a certain point, and beyond that, are there to add drag. In the past, flaps would hang out in a rather extreme way because jets needed to keep their engines spooled up higher in the case of a go around (707 would go out to Flap 50). Spool times are much better now. As mentioned earlier, lift increases induced drag, so extending flaps adds drag at all settings, though it's mostly drag at higher flap settings. The result of this would be that you could descent at steeper angles than you would without, but they're definitely not there to slow you down. They're there to allow you to remain in the air after slowing down.

 

Spoilers and speed brakes are there to slow you down. Spoilers allow increased rates of descent by reducing lift. One can also slow down quicker using spoilers because the spoilers reduce lift, requiring a pitch up to compensate, which adds drag, and therefore reduces speed. Speed brakes allow for increased rates of descent by adding drag.

Actually Vernon, my comment should be taken more as a compliment to you. I am amazed at how deep you dig into things and admire you for it. Keep at it. You´d have tons of fun.

 

If I need to slow down, I will use whatever is available to me that induces drag. Flaps is not something you extend to later retract, whereas the speedbrake is. So yes I prefer to use speed brakes for high speed descents when I need to get down or slower. But if a phase of flight includes permanent or continuous slow down, then I willl use flaps before speed brake or even both if necessary.

I suppose you have flown in real life and took ground studies.

 

AS  far  as I know  Kyle  has  his  pilot  licence  and  does  abit of  flying during the weekends. Kyle  can  confirm this  if  iam wrong

Actually Vernon, my comment should be taken more as a compliment to you. I am amazed at how deep you dig into things and admire you for it. Keep at it. You´d have tons of fun.

 

I do have oxford aviation PPL ground studies and the complete ATPL theorys studies on CDs. Need to check out the performance parts.

AS  far  as I know  Kyle  has  his  pilot  licence  and  does  abit of  flying during the weekends. Kyle  can  confirm this  if  iam wrong

 

I wasn't saying that in a smart way but just saying he should know as he flys light aircraft and gone through ground school

AS  far  as I know  Kyle  has  his  pilot  licence  and  does  a bit of  flying during the weekends. Kyle  can  confirm this  if i am wrong

 

Correct. Some weekdays, too, if I can escape the clutches of the FAA early, depending on what's going on and who needs to go where. I imagine I'll be doing more flying in the next year or so.

 

 

 

I wasn't saying that in a smart way but just saying he should know as he flys light aircraft and gone through ground school

 

Small and medium by FAA definition, but yes.

 

 

If I need to slow down, I will use whatever is available to me that induces drag. Flaps is not something you extend to later retract, whereas the speedbrake is. So yes I prefer to use speed brakes for high speed descents when I need to get down or slower. But if a phase of flight includes permanent or continuous slow down, then I willl use flaps before speed brake or even both if necessary.

 

THIS ^^^^^