For “short takeoff” on pavement, my impression flaps rarely matter in terms of actual numbers
I recall something like the “optimal short takeoff” goes as follow:
- clean flaps during ground roll
- full flaps at VS0 to lift off and stay level
- partial flaps between VS0 & VS1 and accelerate to VX
- best climb angle flaps at VX until you clear obstacles
- best climb rate flaps at Vy until you reach 1000ft agl
I can do a “lazy short takeoff”: partial flaps during ground roll, liftoff and accelerate in ground effect to Vy and climb clean utill 1000ft agl, if the practical difference is 10ft or 20m ground distance until 50ft, one could wonder why bothering theorising this?
For “soft takeoff” on muddy wet grass it’s different, flaps do matter a lot
I recall bumping full flaps to liftoff in PA18-150 before cleaning them again, it looks cool like bush pilots but it barely reduce takeoff distance by 10m, by comparison the PA18-95 does not have flaps and the only benefit of flaps seems to be when grass is muddy & wet rather than some L/D optimisation, on pavement, the difference in STOL performance is purely explained by engine power mostly rather than how I move flaps on takeoff but it looks cool…
However, using flaps does not seem right for takeoff in “high density” altitude, you have to accelerate in ground effect until you get bored, if you can’t you want to know about it while wheels are on the ground 
Maybe I mistranslated when I wrote about stages of flap, maybe I should have used “notches”.as Dan has done.
On the Robin and other French aircraft of similar ilk we tend to use the word “cran” which looking at a French – English dictionary does actually translate as “notch”
Looking out of the side window on a Robin it would be very difficult to assess accurately whether flaps were at 10°15° or 20° instead of that looks about right for 1 notch or 2.
PS: lot of electric flaps have continuous setting from clean to full, I make the a joke “today we need 1/12 flaps”
My experience has been that every plane I’ve flown whose flaps were not manual, have flaps which could be set at any desired angle.
I did not realize that the term “stage” resulted from translation from French, that makes some sense. “Notches” is an accepted term in Canada, and common to C180/185 operations.
LeSving wrote:
In a training setting, taking off with “one notch” is never wrong.
In a training setting, lots of things you wouldn’t normally do is “not wrong.” The problem, if you consistently use 1 notch of flaps when it is not called for is that it creates a bad habit with the student. Why would you want to use 1 notch of flaps on takeoff with a PA28?
We always talked about ‘stages’ when I learned to fly on PA38s.
edit: The term seems to be used in official publications as well.
Ibra wrote:
Maybe zero flaps is negative setting to be used in cruise only? I also recall max RoC was obtained with one notch of falps, can you confirm?
Have to look in the POH. But 1 notch is what gives best glide ratio. Looking at the flaps (flaperon) they look definitely “flush” when up, and notch 1 is definitely “down”.
Airborne_Again wrote:
In a training setting, lots of things you wouldn’t normally do is “not wrong.” The problem, if you consistently use 1 notch of flaps when it is not called for is that it creates a bad habit with the student. Why would you want to use 1 notch of flaps on takeoff with a PA28?
You are mixing two things. One is learning to fly, the other is flying your aircraft correctly (correctly being according to the POH). Proper flaps operation during take off and go around etc should be muscle memory IMO. For many aircraft you may not need that muscle memory, but in the cases you do, it will prevent lots of unnecessary “stuff”. The point isn’t constantly using “1 notch of flaps” for take off, but having the procedure to put flaps up at the right alt and speed etched into your bones. The same could be said about retracts. But while 99% of aircraft have flaps, only 1% have retracts. Still, the standard procedures for gliders (here in Norway at least) is to check gear on downwind regardless.
LeSving wrote:
One is learning to fly, the other is flying your aircraft correctly (correctly being according to the POH). Proper flaps operation during take off and go around etc should be muscle memory IMO.
The PA28 POH recommends either no flaps or two notches (25°). So why use one notch of flaps on a PA28 and not two!?
Airborne_Again wrote:
LeSving wrote: One is learning to fly, the other is flying your aircraft correctly (correctly being according to the POH). Proper flaps operation during take off and go around etc should be muscle memory IMO.The PA28 POH recommends either no flaps or two notches (25°). So why use one notch of flaps on a PA28 and not two!?
No idea! But it is how I was tought.
