Gear Down, Pitch Up

[dfgreene61]

The only Mooney I've flown is my own J.  So I'm not sure if this is normal or not.  When I lower my gear, the plane will pitch up.  Eventually once it slows the nose will come back down.  I'm in the habit of pushing the yoke while the gear comes down to maintain pitch.  Is this what you experience as well?

 

[Shadrach]

I fly a mid-body (F model) and cannot say I've ever noticed this phenomenon. When I drop the gear (all other things being equal) the plane pitches down slightly and begins to descend. I cannot envision how the scenario you describe would occur.  Does the plane actually climb when you drop the gear?

[peevee]

I notice some pitch moment, but not as bad as the flaps.

[Shadrach]

2 minutes ago, peevee said:

I notice some pitch moment, but not as bad as the flaps.

Wait, you're saying your plane pitches up when you add flaps?

[jastu23]

I have a J model and can say I experience the exact same behavior. In my transition training and the proficiency programs I have attended, I heard it was very common. Now, its muscle memory. If it ever stopped doing that I'd lose a couple hundred feet. Take care!


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[peevee]

19 minutes ago, Shadrach said:

Wait, you're saying your plane pitches up when you add flaps?

shocking, isn't it.

I just lead config changes with some trim. Flaps up, trim down, flaps down, trim up.

[jonhop]

1 hour ago, dfgreene61 said:

The only Mooney I've flown is my own J.  So I'm not sure if this is normal or not.  When I lower my gear, the plane will pitch up.  Eventually once it slows the nose will come back down.  I'm in the habit of pushing the yoke while the gear comes down to maintain pitch.  Is this what you experience as well?

 

My J does the same... pitches up slightly while in transit but when the gear is down and locked, the plane slows and the nose drops. I do push the yoke in during the gear transit in order to maintain altitude...

[Shadrach]

5 minutes ago, peevee said:

shocking, isn't it.

I just lead config changes with some trim. Flaps up, trim down, flaps down, trim up.

I would not say shocking, but it's hard to believe without witnessing it. We fly the same basic airframe but yours with more weight on the nose and a more forward CG somehow overcomes theses attributes and does the opposite of other mid-bodies (and short bodies...and long bodies). I am curious as to the why and how given that lowering flaps increases the effective angle of incidence (meaning that for a given AOA the pitch of the nose will be lower).  Any other rocket/missle drivers experiencing this phenomenon?

[Shadrach]

Just now, jonhop said:

My J does the same... pitches up slightly while in transit but when the gear is down and locked, the plane slows and the nose drops. I do push the yoke in during the gear transit in order to maintain altitude...

My guess is this may be unique to the electric gear birds.  Perhaps during the gear drop there is a position that causes a momentary pitch up that manual gear owners don't notice during a one second gear swing.

[jonhop]

Just now, Shadrach said:

My guess is this may be unique to the electric gear birds.  Perhaps during the gear drop there is a position that causes a momentary pitch up that manual gear owners don't notice during a one second gear swing.

Quite possible... could be the inner gear doors or it could be the increased drag under the wing that results in more lift as the gear transits. From what I read on MS, manual gear swings are much quicker than our electric gear. Pure speculation of course...

[Hank]

15 minutes ago, peevee said:

shocking, isn't it.

I just lead config changes with some trim. Flaps up, trim down, flaps down, trim up.

So you are trimming to make the movement worse? Flaps down, trim up--this tells me you are getting nose down movement when lowering flaps (just like the rest of us), but maybe more than you want. My nose moves down with flaps down and up with flaps up. Or are you actually saying that when  you lower flaps, your nose comes up and you trim up for more movement?

I've also not noticed much when dropping the gear, but to follow the glideslope at 90 KIAS, I have to drop the gear 1-1/2 dots above the glideslope. They do make an effective brake, and I'm pretty sure that it is my pitching slightly down to maintain 90 KIAS that is responsible for the descent, it just takes time for it to manifest itself. Yes, I have electric gear, electric flaps and an IVSI, so whatever changes, I see it right away. 

[Shadrach]

9 minutes ago, jonhop said:

Quite possible... could be the inner gear doors or it could be the increased drag under the wing that results in more lift as the gear transits. From what I read on MS, manual gear swings are much quicker than our electric gear. Pure speculation of course...

Been a while since I was in an electric gear bird, but I'd guess 4-5 seconds. Manual is about a second (for me anyway).

[Hank]

Just now, Shadrach said:

Been a while since I was in an electric gear bird, but I'd guess 4-5 seconds. Manual is about a second.

I forgot to time mine during annual last month, but on jacks it was 2-3 seconds one way and about 5 seconds the other way. Those who have put in 40:1 gears will take twice as long, and require double my own 52 turns on the Emergency crank to put them down. No idea how many pulls are on the behind-the-seat ripcord . . . 

[Shadrach]

6 minutes ago, jonhop said:

Quite possible... could be the inner gear doors or it could be the increased drag under the wing that results in more lift as the gear transits. From what I read on MS, manual gear swings are much quicker than our electric gear. Pure speculation of course...

I doubt the gear is creating more lift.  More likely that it's shifting the center of lift forward momentarily causing the slight pitch up.  I've never experienced it, so I am learning something new.

[Yooper Rocketman]

I never put any thought into it, but mine pitches up momentarily on gear extension too.  In short order it settles into a descent without any trim input but I am usually adding some trim to pitch back up some and slow it down.  

Tom

[dfgreene61]

Thanks guys, I was pretty sure it is normal in a J.  Good to hear other J owners experience the same phenomenon.   I'd sure like to know why however, seems like the additional drag under the plane would pull the nose down.  The reason I'm interested in this now is that I'm starting my IR.  When putting the gear down at the FAF I have to be prepared to push the yoke until cycle is complete and the nose up effect goes away.  VFR it never phased me but when flying IFR I'm more conscious of altitude gain during the gear down cycle.

 

[Guitarmaster]

My "F" does the same thing.

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[bradp]

Slight pitch change with gear extension is normal in a J. I'd hazard that it's due to a moment change with the nose gear and drag with the doors opening. The flaps go down and the nose goes down. The flaps retract and the nose goes up. Experienced mid body owners dial in the trim during flap changes and note that the trim speed matches the flap speed exactly so there is no net pitch change if run together. I'm not sure if this is a design feature or a happy accident. Note that on Cessna the opposite pitch change (not desirable) happens when you deploy the flaps. When adding drag you want what we have, which is the nose to pitch down so there's less chance of inadvertently getting on the way back side of the power curve.

 

 

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[peevee]

23 hours ago, Shadrach said:

I would not say shocking, but it's hard to believe without witnessing it. We fly the same basic airframe but yours with more weight on the nose and a more forward CG somehow overcomes theses attributes and does the opposite of other mid-bodies (and short bodies...and long bodies). I am curious as to the why and how given that lowering flaps increases the effective angle of incidence (meaning that for a given AOA the pitch of the nose will be lower).  Any other rocket/missle drivers experiencing this phenomenon?

It's not limited to the rocket. Every mid body mooney I've ever been in pitches with flap change.

[Shadrach]

Just now, peevee said:

It's not limited to the rocket. Every mid body mooney I've ever been in pitches with flap change.

Up...you said yours pitched up. That was where the confusion was.  Mooneys pitch down with flap extension, unless of course one flies the approach inverted.

[peevee]

5 minutes ago, Shadrach said:

Up...you said yours pitched up. That was where the confusion was.  Mooneys pitch down with flap extension, unless of course one flies the approach inverted.

I just said it backwards.

[Robert C.]

My Ovation pitches down when I extend the gear. Actually convenient when flying an approach. I drop the gear at the FAF and hardly need any control input to start and maintain the descent on glideslope.

[Shadrach]

Just now, peevee said:

I just said it backwards.

I understand that now! I initially took you at what you said, not what you meant to say (I think ~40% of the worlds problems are caused by this).  I have zero time in Rockets/Missiles so I didn't know if it was a peculiarity to those birds that I was unaware of.

[peevee]

14 minutes ago, Shadrach said:

I understand that now! I initially took you at what you said, not what you meant to say (I think ~40% of the worlds problems are caused by this).  I have zero time in Rockets/Missiles so I didn't know if it was a peculiarity to those birds that I was unaware of.

it's the way my brain works, rather than think pitch down/pitch up when the flap lever goes down the trim goes the same way, back. When the flaps come up, the trim goes forward, same direction.... sort of.

[Hank]

34 minutes ago, peevee said:

I just said it backwards.

Yeah, you confused me, too . . . Now it all makes sense!