Flaps and Lift argument

[Fozzer]

Foz. Many light aircraft use the "Plain Flap" which works on a basic hinge. There is a variation called the "Slotted Flap" which involves an inset hinge point. The principle of a Fowler flap is different in that it slides back on a rail or track while extending, creating a gap between the wing & the leading edge of the flap. The Fowler flap has a streamlined aerofoil section to smooth out the airflow in the gap. Most modern airliners use a more complex multi-slotted Fowler flap like this example on the Boeing 727.

Mornin' Doug...!
Thanks for the info... ...!
So all my little babies have "Plain Flaps"....sorted... ...!
"Plain" I like, as in plain English, plain flour, etc,.. ...!
LOL...LOL...LOL...!

Cheers mate, have a good week-end... ...!
Paul.
(Hereford).

[Hagar]

Hi Foz. I was surprised to realise the single engined Cessnas now use the simple flap where the complete trailing edge is hinged. Never really thought about it. I'm sure at least some Cessnas I saw back in the 60s had the Split Flap, like the ones on your Austers (& Ozzy's Spitfires).



Have a good weekend yourself. I'm off out to enjoy some of this sunshine.

[Jim_Hanna]

Hi guys
           On this question on the purpose of flaps, if you will allow me l'm put on my old airframe fitter's hat from my R.A.F. days. as l remember it the use of flaps is all tied in with the theory of lift, and we cover that sort of thing in the airframe course.  
          Flaps increase lift, but as lift and drag are tied together and work in opposite directions the use of flaps also increases drag.  To counter the increase in drag when the flaps are lowered the pilot adds a little power. Anytime you fly on a commercial flight you will notice as the flaps are lowered the engines will run up a touch.
         it is also correct that Concorde does not have flaps, neither has the Vulcan.  Their large delta wing also acts as a huge airbrake.  l can remember many years ago sitting by the side of the runway at St Athan in South Wales watching the vulcan land. when the main wheels settled on the runway the pilot would lift the nose. The huge delta would trap the air beneath and the aircraft would almost stop dead on the spot, quite a sight.  So there we go flaps increase lift, but also increase drag.

[visitor]

This tread sure gave me a pick me up,
I needed a lift this morning!!!

X

[fisharno]

So, I guess the moral of the story, AstroGeek, is that you and your friend were both right, in a way.

[Rifleman]

Since Hagar has come so close, shall I now enter into a dissertation on the other grand device for landing, and thats the "spoiler"?...all this lift/drag stuff is my beautiful world of gliders...when you have no power source other than the potential energy of altitude, you need to address lift/drag and what controls both to fly effectively......
...and about the miss that Hagar introduced, Deltas use "elevons" not "flaperons".........they control pitch by moving in the same direction and roll by moving in opposite directions........flaperons are ailerons which can be drooped to provide some measure of extra lift in addition to the flaps, while still moving differentially to give the necessary roll control.........for maximum drag on a glider, we use 90 degrees of down flap for drag(dgar) while utilizing 45 degrees of up aileron for spoiler, to reduce lift and shorten effective wingspan, hence increasing effective wingloading and increasing effective sinkrate, and slowing the descent while not increasing airspeed .........landing is imminent........

I could go on for hours on this one...........  8)  ;)  ;D

[Rifleman]

This tread sure gave me a pick me up,
I needed a lift this morning!!!

X

If I was dealing with a tread, I'd keep it on the tires of my car..........get better traction with good tread.......  ::)  ;D  ;D

[Lethal.Ambition]

Actually, most of the "lift" a wing generates is due to the area of lower pressure on the TOP of the wing.

OK I am getting this thing now........my next question is: If most of the lift a wing generates is on the top then how do the flaps help to create lift on the bottom? or did I understand wrong

[Rifleman]

Here is the lowdown.....lift is a function of airfoil shape, wingspan, wing area(varied by Fowler flaps and leading edge flap droop and open slots to keep airflow attached), angle of attack(Varied by amount of Fowler flap deployed), and airspeed, and then has drag acting upon it and is varied by Fowler flap, lead edge flap, and spoiler deploymemt......
Quite simple, .........innit ?.......

As for the "lift" being developed by either the upper or lower surface, you can develop your own theory which is more important, as its a pressure differential which always moves a high pressure area into a low pressure area.........high under the wing trying to move towards the low pressure above the wing, which in turn supports the weight of the A/C.......

There is also another school of thought which has a different view on this and its more like surfing on water than pressure differentials....but thats a whole, 'nother ball of wax...........  ???

[Craig.]

also to add, alot of how the air is directed is decided by those canoes on the underside of the wings, i am not sure of the ins and outs of them but i know they play an important part in airflow under the wing when flaps are deployed

[Rifleman]

Those canoes you speak of are actually the streamlining fairings for the sliding rails which contain the moveable pivot points for the mult-slotted Fowler flaps .....they slide back and pivot down, to do their intended job......

[Hagar]

...and about the miss that Hagar introduced, Deltas use "elevons" not "flaperons".........they control pitch by moving in the same direction and roll by moving in opposite directions........flaperons are ailerons which can be drooped to provide some measure of extra lift in addition to the flaps, while still moving differentially to give the necessary roll control

LOL. You caught me out there. I hang my head in shame.  ::)

I could go on for hours on this one...........  8)  ;)  ;D

I could also go on for hours. I'll cover the reflex angle for the control surfaces on deltas another time.  ;)

[Lethal.Ambition]

Than ks for a  ;D the rep lies guys!! I got ever ything n ow! ! And I learned a little extra along the way i n how Conorde don't have flaps, but  ;Duse the del ta wing to brak e, very  ;Dcoo l!

Th anks again guys, for everything!

[Rifleman]

[quote]
I'll cover the reflex angle for the control surfaces on deltas another time.

[Hagar]

[quote]
Not just deltas......Most flying wings use some form of "Reflexed" airfoil to aid in "Longitudinal Dihedral"......(pitch stabilization)....whether its from control surface offset or its built into the actual airfoil profile.....