When do you use takeoff flaps?

[201er]

I know some of you use flaps on takeoff, other don't, and other vary. Let's have a vote and discussion about when you use takeoff flaps and why. And why don't you use takeoff flaps at other times. I find these discussions if not educational then at the very least entertaining.

[Bob_Belville]

I always use t/o flaps. Not sure why I would want to keep bouncing down the runway building an extra 5-10 k before rotating? 

[carusoam]

Ovation procedure says use flaps at T/O setting...

So I do...

Best regards,

-a-

[Skywarrior]

"When do you use takeoff flaps?"

 

Takeoff.

[DaV8or]

"When do you use takeoff flaps?"

 

Takeoff.

 

That sums it up for me. I can't think of a reason not to use them.

[BigTex]

Almost never.

[carusoam]

Somebody should re-write the performance section for the M20C POH or AFM, matching the performance data that is available for the Ovation...

the iPad and various apps can demonstrate the value or lack of value? of the flaps.

T/O distance should improve with flaps...

Complexity increases with use of flaps as well...

My non expert C "training" included not using T/O flaps and landing using 1/2 flaps. This simplified trimming and smoothed landings...

And probably used a lot more runway in exchange....

Best regards,

-a-

[1964-M20E]

Only on grass, soft or short runways.  paved long runways no flaps

[Bob_Belville]

 

(this 1968 accident was my Mooney, many years before I bought it. Note the probable cause:)

 

14 CFR Part 91 General Aviation Aircraft: MOONEY M20E, registration: N2566W

 FILE    DATE          LOCATION          AIRCRAFT DATA       INJURIES       FLIGHT                        PILOT DATA      F  S M/N     PURPOSE

3-2768  68/8/17    OAKDALE,CALIF       MOONEY M20E         CR-  0  0  1  NONCOMMERCIAL             PRIVATE, AGE 39, 448

        TIME - 1410                    N2566W              PX-  0  0  2  BUSINESS                  TOTAL HOURS, 250 IN TYPE,

                                       DAMAGE-SUBSTANTIAL  OT-  0  0  0                            NOT INSTRUMENT RATED.

        NAME OF AIRPORT - OAKDALE

        TYPE OF ACCIDENT                                         PHASE OF OPERATION

           STALL: MUSH                                              TAKEOFF: INITIAL CLIMB

        PROBABLE CAUSE(S)

           PILOT IN COMMAND - FAILED TO OBTAIN/MAINTAIN FLYING SPEED

        FACTOR(S)

           PILOT IN COMMAND - MISUSED OR FAILED TO USE FLAPS

           PILOT IN COMMAND - SELECTED WRONG RUNWAY RELATIVE TO EXISTING WIND

           WEATHER - HIGH TEMPERATURE

        WEATHER BRIEFING - NO RECORD OF BRIEFING RECEIVED

        WEATHER FORECAST - UNKNOWN/NOT REPORTED

        SKY CONDITION                                            CEILING AT ACCIDENT SITE

          CLEAR                                                    UNLIMITED

        VISIBILITY AT ACCIDENT SITE                              PRECIPITATION AT ACCIDENT SITE

          5 OR OVER(UNLIMITED)                                     NONE

        OBSTRUCTIONS TO VISION AT ACCIDENT SITE                  TEMPERATURE-F

          NONE                                                      85

        WIND DIRECTION-DEGREES                                   WIND VELOCITY-KNOTS

          315                                                       5

        TYPE OF WEATHER CONDITIONS                               TYPE OF FLIGHT PLAN

          VFR                                                      NONE

        REMARKS- QUARTERING TAIL WIND 5 KNOTS. NO FLAPS. TEMP 85 DEG.

[kmyfm20s]

I always felt like plane were meant to fly, not hall ass down the runway. I also feel there is a much better safety factor with the flaps down.

[Hank]

Per my Owners Manual: Flaps--TAKEOFF or as desired.

My desire fluctuates with runway surface, condition, obstacles, load and winds; DA is not often a concern where I fly.

See the Flap Retraction poll for my philosophy on Takeoff Flaps, I saw that one first. Either way, The Book says to rotate at 65-75 mph, so I usually compromise on 70 mph.

[Rich]

During one of my MAPA PPP programs, I was shown (for rough runways only) a full flap takeoff. It works well if you're on your game. Otherwise, as per the manual is what I use regularly. 

[Super Dave]

I only use TO flaps if required by a short field, close-in obstacle, or if using soft field technique on a rough surface.

Aside from adding complexity to the climb out, TO flaps will degrade climb gradient and rate. Especialy as the airplane accelerates during the transition to flaps up. Also, the lower airspeeds used while the flaps are still down result in less cooling for the engine in the early part of the climb. I'd rather sacrifice the tires/landing gear to an extra few hundred feet on the runway, than sacrifice a few extra knots to cool the engine in the climb.

[Bob_Belville]

I only use TO flaps if required by a short field, close-in obstacle, or if using soft field technique on a rough surface.

Aside from adding complexity to the climb out, TO flaps will degrade climb gradient and rate. Especialy as the airplane accelerates during the transition to flaps up. Also, the lower airspeeds used while the flaps are still down result in less cooling for the engine in the early part of the climb. I'd rather sacrifice the tires/landing gear to an extra few hundred feet on the runway, than sacrifice a few extra knots to cool the engine in the climb.

Dave, your comments seem to be contradictory to me. You use flaps for obstacle clearance but then state that flaps degrade climb gradient and rate.

 

I'm not sure what kinds of flaps your F has, my E is hand pump hydraulic so I simply flip up the valve right after locking the Johnson Bar in place. In a few seconds I am clean and terrain permitting I'm looking for 120k or so to climb as cool as possible. From about 300' AGL we're in the same mode. I'd just rather be in my Chrysler Crossfire than in my Mooney when I'm doing 80 mph on the ground. 

[RJBrown]

TO flaps to take off!

Why run the tires more than you need.

Why have multiple "normal" procedures?

Less chance of an accident if your procedure is the same every time.

No good reason not to do it Right.

[N201MKTurbo]

I stopped using TO flaps about 25 years ago. I'm just lazy, one less thing to do after take off. Besides it takes off smoother without flaps. You don't have to rotate, just drive it down the runway and the next thing you know you're flying!

[Super Dave]

Dave, your comments seem to be contradictory to me. You use flaps for obstacle clearance but then state that flaps degrade climb gradient and rate.

I should explain what I mean by a close-in obstacle. It's the 50' tree at the end of a 2500' strip. Using TO flaps will get you airborne and climbing in less distance, and you will clear the tree with greater margin. In this case, using TO flaps would be the "right" way.

In another example, if we have a 3000' ridge 10 miles from an airport where runway length is not a factor. Imagine two identical airplanes starting their TO roll side by side, one with TO flaps, one clean. The flapped airplane will become airborne earlier and will begin its climb out. The clean airplane will take off farther down the runway, and will for a short time be lower than the flapped airplane. However, the clean airplane will accelerate more quickly and soon be out-climbing the flapped airplane and it will be covering more ground with a cooler engine while doing so. If the clean airplane isn't already higher by the time of flap retraction, it will be as flaps are retracted. It doesn't matter if the flaps come up slowly or in the blink of an eye; the airplane will need to accelerate, and sacrifice climb in doing so. The airplane that took off clean will cross the ridge sooner and with greater margin. In this case, taking off clean (assuming your POH allows it; mine does) would be the "right" way in my mind.

Some of this may seem counter intuitive, but you have to remember that climb performance is based on excess power or thrust, not excess lift. The additional lift provided by the flaps gets us airborne sooner. But once airborne, the flap's additional drag reduces excess power/thrust and degrades climb performance.

[Bob_Belville]

Dave, thanks for the explanation. I suspect the differences in engine temps and climb profiles are going to be pretty trivial between taking off w/o flaps vs. 15 deg flaps to 2-300 AGL. By the time we're to @ pattern altitude we're flying at the same power and airspeed. One or the other of us might be slightly more down range. 

[Super Dave]

Dave, thanks for the explanation. I suspect the differences in engine temps and climb profiles are going to be pretty trivial between taking off w/o flaps vs. 15 deg flaps to 2-300 AGL. By the time we're to @ pattern altitude we're flying at the same power and airspeed. One or the other of us might be slightly more down range.

I agree, but by the same token, I'm guessing that the extra tire/gear wear and tear caused by a flaps up TO is equally trivial.

[gregwatts]

For me........it depends on circumstances......ie: runway length, obstacle clearance, condition of runway, etc.....but most often, I use no flaps for takeoff.

 

Most often I use 1/2 flaps for landing........again.....depending on circumstances.

[Oscar Avalle]

I use take off flaps most of the times Sent from my iPad using Tapatalk HD

[N9201A]

Do both.  Learn the differences, and be proficient with our aircraft in multiple configurations.  The truth is there is no "one" answer;  what works best on a short/soft, "obstacle-y" environment may not be best in a gusty, big runway scenario.  

 

We've developed quite a bit of experience in the Mooney Caravan flying everything from Cs to Bravos together and no-flaps, 70 knot takeoffs work great ... after much consternation over "no flap" takeoffs from those in the "no reason not to" camp.  They're always converted once they've tried it and seen others do it.

 

But let's not get started on the "no flaps landing" debate ...! 

[201er]

I agree that for the way the caravan operates, no flaps may be best.

 

However, for all normal Mooney operations, the best argument for ALWAYS using takeoff flaps is to establish it as SOP so that the one time you really need them, you didn't forget to use them!

[fantom]

You guys have me considering doing no flap T.O.s and no flap landings all the time. I'll get the flaps smoothed into the wings and pick up at least 3 kts.

[N9201A]

Certainly if one is flying other aircraft, the failure to extend takeoff flaps can have much more serious considerations.  But our flaps are easy enough (compared to swept-wing equipment) to confirm status visually.  I have heard the "SOP 100% to prevent omission" argument used against leaning on the ground, too.  Ultimately, each of us is PIC and does what works for each of us individually.  I like to practice short/soft and max rate TOs and landings regularly, so I mix up my flying and configurations enough where that argument doesn't make sense for me.  When I need the flaps/short performance, I certainly want to have it!  I'm always surprised at how few people try reduced power takeoffs until one is forced upon them when they find themselves at a high-elevation field;  the distances used are significantly different enough to open one's eyes.  I really believe if more of us did this at low-elevation fields, there'd be fewer hot-high-heavy takeoff and landing incidents.   

 

I once had my flaps rendered inop, which turned out to be the microswitch (accessible through the belly panel) being sticky.  A little WD40 cleared it up, and others have told me jiggling the flaps worked.  I was glad the flaps were stuck "up", so it did not interfere with my trip.