M20J Takeoff Flap Question

[planeflyer4u]

(New to the 201)  Is it Normal to experience pitch up of the nose when retracting  take off flaps during  climb out? Im new to the 201 (1977M20J ) but when preforming normal take off using take off trim position and take off flaps, rotating at approx 70 mph it requires additional back pressure to liftoff,once breaking ground it climbs well,gear retraction has no pitch or trim change but when I retract the flaps the nose pitches upward requiring considerable down nose trim . Ive flown M20E models etc and didnt get this reaction any thoughts ? Thanks for any Input ...

[gsengle]

On my R, there is a really mild pitch up with flap retraction, but not much. The big pitch down happens with full flap extension.


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[planeflyer4u]

Everything seems as it should be during cruise flight and landing phase ,just the nose up when flaps retracted in the climb, most A/C ive flown seemed to require trim up when retracting flaps .... I appreciate the Input Thanks 

 

 

[Shadrach]

Indeed it is perfectly normal.  The effective angle of incidence decreases and the center of lift moves forward. It certainly requires retrimming the aircraft.

[Danb]

Yes I do believe there is pitch up, reason you re trim the plane doing touch n goes 

[carusoam]

Mooneys, flaps, and go arounds...

Three good things to cover during transition training.

Adding full flaps for landing, the yoke gets pretty heavy until the trim is set up properly.

Adding full power with the flaps down for a go around, the nose points to the sky unless the pilot is quick with the yoke and trim.

Get some hours in with a Mooney proficient CFI.

The wing characteristics change where the center of lift is as the flaps get added or removed.  Plan on it.

Newer Mooney's were designed to have the trim and flap motors operate at the same speed.  Technique....

The full design range of the Mooney trim gets used.  There isn't much excess designed in.  The trim is near the back during landing with full flaps.  It is pretty far forwards at high cruise speed.  Not having the trim set properly for the current phase of flight has some pretty strong forces associated with it.

Pp ideas, not a CFI...

Best regards,

-a-

 

Edited April 26, 2017 by carusoam

[Shadrach]

Just now, bluehighwayflyer said:

Of course, Ross. But would you consider "considerable down nose trim" being required normal?  IDK but that sounds exaggerated based on my experience. Mild yes. Considerable, not so much. A question of degree, though, for sure. 

I think it will depend on climb AOA.  I think "considerable" is a strong word.

[Marauder]

34 minutes ago, planeflyer4u said:

(New to the 201)  Is it Normal to experience pitch up of the nose when retracting  take off flaps during  climb out? Im new to the 201 (1977M20J ) but when preforming normal take off using take off trim position and take off flaps, rotating at approx 70 mph it requires additional back pressure to liftoff,once breaking ground it climbs well,gear retraction has no pitch or trim change but when I retract the flaps the nose pitches upward requiring considerable down nose trim . Ive flown M20E models etc and didnt get this reaction any thoughts ? Thanks for any Input ...

Just a few checks... When you are flying around at cruise, where is your trim indicator indicating? "Pulling the plane off" sounds like a trim that is too far nose down versus the indication of it being in the takeoff position on the indicator. When you land using full flaps, where is the indication? On my late model F, I have almost all nose down in cruise and I am an indicator's width above the takeoff indication on landing.

 

[Shadrach]

All good point's gent's but the pitch up with take off flaps is mild compared to full flaps.  Perhaps the take off position is improperly set.

[gsengle]

Good point, you're taking off with one, not two, notches of flaps, we assume?


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[bradp]

You get a slight (maybe 2 degree) nose up retracting flaps from takeoff to retracted position.   I usually don't touch anything and ride it through at about 110-120 mph.  The acceleration and little bit of nose up effectively cancel each other out and you get a nice cruise climb of about 120 mph.  

If you are climbing out at Vx or Vy I can imagine a more pronounced change in the center of lift - but there aren't too many people who will climb out at Vy - most sink into where the plane wants to be at that other speed (Vz? Iirc) where the wing climbs most efficiently.  

Occasionally you should do a no flaps takeoff to see what that feels like. 

If you have electric trim when extending the flaps you can run the trim nose up and you should not get any net pitch change. 

[Shadrach]

7 minutes ago, Marauder said:

Just a few checks... When you are flying around at cruise, where is your trim indicator indicating? "Pulling the plane off" sounds like a trim that is too far nose down versus the indication of it being in the takeoff position on the indicator. When you land using full flaps, where is the indication? On my late model F, I have almost all nose down in cruise and I am an indicator's width above the takeoff indication on landing.

 

Have you had your tail rigging checked? Same airframe and I do not cruise anywhere near almost all nose down. 

[Marauder]

3 minutes ago, gsengle said:

Good point, you're taking off with one, not two, notches of flaps, we assume?


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I was thinking the same thing but being the nice guy I am, I wasn't going to ask. It would make a world of difference if he is taking off with full flaps.

[peevee]

Normal in both k models I've flown regularly. Lead with trim...

[Shadrach]

As a visual aid you can see me go from full flaps to flaps up at  00:36 and 01:41.  I am compensating slightly with forward elevator and then trimming the pressure out of the yoke, but raising flaps should cause little drama.  The higher your AOA the more dramatic the change in pitch.  In the video I am raising flaps at 90mph but I am not attempting a steep climb (full flaps makes for a very flat climb profile).

 

[Glenn]

I believe what you are experiencing is normal.  In my "F" after I retract flaps on take-off it takes 10 forward swipes of the trim wheel to trim for climb out.  This is not too surprising, given that I was probably trimmed for ~75 MPH (older airspeed indicator) to rotate. and am now trimming for a climb speed Vy of 113.

[Shadrach]

Just now, Glenn said:

I believe what you are experiencing is normal.  In my "F" after I retract flaps on take-off it takes 10 forward swipes of the trim wheel to trim for climb out.  This is not too surprising, given that I was probably trimmed for ~75 MPH (older airspeed indicator) to rotate. and am now trimming for a climb speed Vy of 113.

That is not my experience.

[ArtVandelay]

IIRC, it's opposite of the 172, so it might seem considerably, yes it's probably normal, what concerns me is you don't seem not have any transition training.

[N201MKTurbo]

Just take off without flaps and you won't have anything to worry about.

[peevee]

35 minutes ago, N201MKTurbo said:

Just take off without flaps and you won't have anything to worry about.

I don't really like 0 flap takeoffs. They feel....wrong

[N201MKTurbo]

9 hours ago, peevee said:

I don't really like 0 flap takeoffs. They feel....wrong

When I was ferrying that Rocket recently I did no flap takeoffs. It was little different than my J except I was milking the throttle up and by the time I got to 32 inches I was airborne. Oh well, I didn't need all that power anyway.

I've been doing no flap takeoffs for so long, taking off with flaps seems weird.

To each his own...

[kevinw]

I never run the flaps, up or down, without running trim in the opposite direction. As noted previously the motors run at the same speed so if you time it correctly there is absolutely no pitch. It's become second nature to me.

[Bob - S50]

In our J...

Using 1/2 flaps for takeoff and takeoff trim set at the TOP of the takeoff band, it takes a significant amount of back pressure (10 pounds?) to lift the nose to get airborne.  However, once airborne the trim is about right and I don't really notice any pitch change as I clean up.

However, there is a very significant trim change required between 1/2 and full flaps.  For that reason I plan to start using 1/2 flaps for my landings as well but have not done that yet.

Something to keep in mind.  Here is a quote from our POH, "If forward CG set trim to upper portion of band and to lower portion when at aft CG."  So make sure when you only have people up front that the trim indicator is at the top of the band.

As a side note, if I do not hold any back pressure as I roll down the runway, above about 50 KIAS, the plane gets very light in the feet and will tend to skip sideways in a crosswind.  However, if I hold a considerable amount of back pressure, about what it takes to get airborne, it helps keep the feet on the ground until it is ready to fly.

[Oldguy]

I'm not sure how fast you are pulling up flaps after gear retraction, but my J need 2-3 flips of the trim wheel at gear and flap retraction. I come off the ground between 61-64 kts. with no real effort on the yoke when normally (~2500 lbs.) loaded in less than 1,000 ft. with the flaps set at the takeoff position. Gear up, trim down 2-3 flips, flaps up, trim down 2-3 flips and pitch for 100 kts. climb. If I pulled both gear and flaps up about the same time or did not trim between each action, I am certain I would have a significant pitch up moment when I would need to trim excessively.

The suggestion to check flap position indicator with aileron deflection is right on. Once correct location on the indicator is verified, it all should go just as the POH states, at least in my experience.

[gsxrpilot]

21 minutes ago, Bob - S50 said:

Something to keep in mind.  Here is a quote from our POH, "If forward CG set trim to upper portion of band and to lower portion when at aft CG." 

Sorry, but that instruction seems about as obvious as "push throttle forward to go." I can't imagine any pilot needs the POH to tell where to put the trim. Trim as required.