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When do you retract flaps after take-off?


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I was a convert from no flaps on take-off to using take-off flaps in my vintage Mooney.  Question, "When do you retract flaps"?

The POH procedure seems to be after gear on climb out.  Doesn't really give an altitude/time.

Guessing there is some subjectivity here.  Interested in hearing from those that do, really not wanting debate on not using them in this thread.

The when (altitude/time after take-off) and why is what I am interested in.

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I am a bit conservative.  Altitude is life.  1000' AGL @ 95 mph is when I bring the flaps up.  95 mph is the minimum cooling speed for my IO-360.  Note that this leaves me only 5 mph before I am beyond the white arc.

When I met Norman Howell this summer, he talked about his Master's Thesis and the "optimum" climb speed.  For my E model, it is about 130 mph (~110 kts), so no flaps at that speed in my Mooney.  What that speed does is get a plane to its destination quicker (winds aloft not being considered).  What it does not do is get you to 1000' AGL in a hurry.  So good knowledge from Norman, but no change in current procedure.

 

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In my E I actually raise the flaps right after lift off as long as it's not a short field or obstacles off the departure end. I like accelerating to Vy as soon as I lift off so that means the flaps come up. Gear comes up, usually after the flaps, once no more usable runway. Short fields I'm gear up at positive rate, climb at Vx and then flaps up clear of obstacles.


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Flaps increase lift and add drag. Takeoff flaps increase lift to get the airplane off the runway quicker while adding minimal drag. For more than take off flaps the drag increase overwhelms any lift benefit. As speed increases so does lift and the need for flaps diminishes.

Therefore I'm not in a great hurry to clean up takeoff flaps. A white arc with a Vfe of 115 KIAS is very generous. I retract them when speed is well on its way and has safely increased in the climb. Typically around 1000 feet or so.

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2 hours ago, MyNameIsNobody said:

I was a convert from no flaps on take-off to using take-off flaps in my vintage Mooney.  Question, "When do you retract flaps"?

The POH procedure seems to be after gear on climb out.  Doesn't really give an altitude/time.

Guessing there is some subjectivity here.  Interested in hearing from those that do, really not wanting debate on not using them in this thread.

The when (altitude/time after take-off) and why is what I am interested in.

Coincident with this question is when do you raise the gear?  I see many pilots who raise the gear quite quickly, in many cases while there is still plenty of runway to land on should the engine quit.

Clarence

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54 minutes ago, M20Doc said:

Coincident with this question is when do you raise the gear?  I see many pilots who raise the gear quite quickly, in many cases while there is still plenty of runway to land on should the engine quit.

Clarence

Some manual gear Mooney drivers get a little crazy on this imho.  I like to get up and get going and verify all the gauges in the climb before I start dragging things up.  

No rush in my opinion and more to be gained by letting hanging longer than taking it up sooner. 

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57 minutes ago, M20Doc said:

Coincident with this question is when do you raise the gear?  I see many pilots who raise the gear quite quickly, in many cases while there is still plenty of runway to land on should the engine quit.

Clarence

I’m a fairly new pilot but find it is much easier to bring up the gear well before the end of the runway.  My reasoning is I can put the gear down very quickly, it is a lot more difficult to retract the gear at higher speeds where engine cooling is optimal, and it is one less thing to worry about later when things get busy. 

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2 minutes ago, M20F said:

Some manual gear Mooney drivers get a little crazy on this imho.  I like to get up and get going and verify all the gauges in the climb before I start dragging things up.  

No rush in my opinion and more to be gained by letting hanging longer than taking it up sooner. 

Until you wait too long and can be a bit difficult to get them stored especially if your not that strong. I like to verify all is right before rotation get off the ground  stow the gear confirm positive rate of climb and obstacles cleared then retract flaps which occurs just as I'm approaching 100mph my max flap speed. Not too often I'm on a runway that would be long enough that I could still use it if power were lost. Nice thing about manual gear is its down in less than a second.

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7 minutes ago, MIm20c said:

I’m a fairly new pilot but find it is much easier to bring up the gear well before the end of the runway.  My reasoning is I can put the gear down very quickly, it is a lot more difficult to retract the gear at higher speeds where engine cooling is optimal, and it is one less thing to worry about later when things get busy. 

Fewer words and or faster typing

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1 hour ago, M20Doc said:

Coincident with this question is when do you raise the gear?  I see many pilots who raise the gear quite quickly, in many cases while there is still plenty of runway to land on should the engine quit.

Clarence

On a normal departure, I make sure I'm climbing well, have compensated for wind, am in control, and raise gear around treetop level. When using flaps, generally to clear obstructions, i raise them when I'm looking down at the obstructions that concerned me.

Should the engine quit, it takes 3-4 seconds for the gear to cycle down. Using typical 3° glideslope, that's 300-350 fpm, so from 50' I'm ~12 seconds from the runway, plus time changing from climb to descent, plus deceleration and flare.

But raising the gear does wonderful things for my climb rate!

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Just now, daver328 said:

If you had a J bar ... you’d change your tune 

 

I used to own 2 E models, both were manual gear versions,  with more than 700 hours in the left seat on them I do have a bit of experience.

On most normal sized runways I would raise the gear when there was nothing left to land on, or was high enough that landing on the remaining portion was impossible.  

Clarence

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Runway can be used with or without the gear. But once out of useable runway, I'd much rather have the altitude. So my gear comes up immediately on positive rate of climb. If the engine quits at the point of no useable runway, I'll have more altitude and therefore more options.

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Mine is a '62 with the lower flap speed of 100mph.  I want to get those flaps up as soon as possible so I can accelerate for engine cooling purposes.  I'd really like to have the higher flap speed, because I'm somewhat uncomfortable dropping the flaps as as early as I have to for that purpose, but my process is as follows:

After takeoff, gear comes up as soon as I couldn't land on the runway.  I probably push that further than I should.

Once I have established a fairly stable climb again after gear up, I pull the flaps and accelerate to 120mph.

Just my $.02

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1 hour ago, gsxrpilot said:

Runway can be used with or without the gear. But once out of useable runway, I'd much rather have the altitude. So my gear comes up immediately on positive rate of climb. If the engine quits at the point of no useable runway, I'll have more altitude and therefore more options.

Agree, a gear up landing on the last 200' of the runway is likely better than running off the end. At least it is safe. I get the gear up very quickly, then the flaps so that I can get the nose down and the speed up to Vy. Then the boost pump to off with an eye on fuel pressure for a few seconds.

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7 hours ago, Guitarmaster said:

Clear of obstacles and solid positive rate.
Why: The airplane settles with flap retraction. Don't want to be doing that with trees coming up at you.

Sent from my XT1585 using Tapatalk
 

That's what I was taught. 

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8 minutes ago, bluehighwayflyer said:

Geez. I am in the sooner-rather-than-later gear up club, too. But bent prop tips is a whole other thing entirely. I don’t think that anyone is suggesting anything close to that.  If they are shame on ‘em. 

What a couple of us are saying is that we'd rather get the gear up quickly., even with some runway in from of us. If the engine should then quit we'd be willing to do a belly landing. Roll out is very short, injuries are unlikely. Props can be replaced, engines can be torn down, it's only money and most of it is the insurance company's. Beats landing on tires and plowing into trees, a ditch, a fence, or a ravine.  

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Collective C procedures... (summary?)

1) T/O flaps are being used more often now than before...

2) Often they get stowed away at TPA (1k') and the fuel pump gets turned off at the same time.

3) any later they risk being forgotten.

4) flap speeds risk being broken if they don't get stowed in a timely fashion.

5) Wheels up...quickly.  Shorter the runway, less reason to leave them down.

6) Positive rate of climb is everything.  Distractions and multi-tasking challenges are less of a problem at 500' agl and climbing...

7) deeper into the green arc with less of the white arc available, the T/O flaps are no longer as beneficial...

8) at the beginning of the white arc, stowing the flaps would be too soon, as the ensuing dip can be quite strong.

9) high DA, highly loaded, don't be in rush to dump the flaps...

10) cold day, and lightly loaded, flaps can be stowed quickly.

11) know how fast your flaps stow themselves.  A mis-set valve dumps the flaps too quickly.  This will also dump the associated lift without any transition.  This transition is usually measured in many seconds, not one or two...

 

Long Body....

1) Not much different.

2) time and accelerations are going faster.  Vs is over 1000 fpm and can be 2000 fpm

3) positive rate, tap brakes, gear goes up with the switch.

4) climbing over the end of the runway... flap speed are being approached as is the 1000' agl. Raise them before they bend....

5) Same As the M20C, accept the Aux fuel pump has an automated switch related to throttle position.

6) fully loaded and/or lesser powered...  the LB is very M20C like.  :)

 

PP thoughts only, not a CFI...

Best regards,

-a-

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3 hours ago, M20Doc said:

I used to own 2 E models, both were manual gear versions,  with more than 700 hours in the left seat on them I do have a bit of experience.

On most normal sized runways I would raise the gear when there was nothing left to land on, or was high enough that landing on the remaining portion was impossible.  

Clarence

I think the gear motor on my airplane is getting tired, and if I let the airplane accelerate too much it may pop the circuit breaker on gear retraction.   If I get the gear up early (positive rate, no obstacles), it's easier to keep it at Vy and keep the gear motor reasonably happy and then once the gear is up drop the nose a bit for cooling, cruise-climb, whatever.   It doesn't ever pop the breaker if I do it that way.

My gear comes down faster than it goes up, and I have *cough* demonstrated that I can gear the back down in time to land on my home field runway if I really, really need to.

In the Arrow I used to fly, the gear came up sooooooo slooowwly that I used to leave it down until I was completely out of runway or easy landing possibilities.   But it didn't have a problem with either accelerating easily or bringing the gear up at cruise-climb, so that also helped.

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