Mooney J sticking to runway on take off

[rturbett]

With the aircraft loaded well within CG, (two adults, 100lbs baggage mostly in back seat, some in the baggage compartment)  significant force is needed on the elevator to get the plane off the runway and into the air. 

an experienced mooney pilot tried, and noted how tough it was.

I'm looking for potential culprits- the only thing I have come up with is donuts on the nose need to be replaced (mains were done) and I'm wondering if that could lower the angle of attack enough to make us have to pull through it.

we thought the elevator trim indicator might be off- so we put a little extra up in- no real change, and clearly had to hold the nose down once we were in the air.

 

Any thoughts?

Thanks,

Rob

[dzeleski]

35 minutes ago, rturbett said:

With the aircraft loaded well within CG, (two adults, 100lbs baggage mostly in back seat, some in the baggage compartment)  significant force is needed on the elevator to get the plane off the runway and into the air. 

an experienced mooney pilot tried, and noted how tough it was.

I'm looking for potential culprits- the only thing I have come up with is donuts on the nose need to be replaced (mains were done) and I'm wondering if that could lower the angle of attack enough to make us have to pull through it.

we thought the elevator trim indicator might be off- so we put a little extra up in- no real change, and clearly had to hold the nose down once we were in the air.

 

Any thoughts?

Thanks,

Rob

You can measure the compressed stack of donuts and see if they are in or out of spec. To me its a bit odd to just replace the mains, if the mains needed to be done I would have just done the nose as well.
 

When you land, where is the trim indicator? In cruise where is the trim indicator?

Generally when I take off I add a bit more trim then the labeled take off trim (usually the entire indicator is above the takeoff marking). In my J it takes about 10lb of force to get the nose up and then I can immediately relax that pressure and just let it fly.

Edited January 8 by dzeleski

[ArtVandelay]

I’m still think it’s your trim indicator is off, and moving it a little may not be enough.

What’s it look like in level flight at cruise power (~65%)?

[PT20J]

On a J, the trim bungees should center the elevator in alignment with the horizontal stabilizer on the ground with the trim set in the takeoff band. This is a quick check that the trim indicator is correct.

If the trim is set right and you hold a steady ~5lb pull during the takeoff roll, the airplane will rotate and fly off when it’s ready.

EDIT: As the airplane starts to rotate, release the back pressure so that it is completely released as the pitch attitude reaches 7 deg nose up and it will climb out without changing the trim until you raise the flaps. 

Edited January 8 by PT20J
Added comment about releasing back pressure during rotation.

[takair]

Depending on what you are used to, the Mooney does take a little more pull for the initial rotation, due to training link gear.  At that point it is almost easy to over-rotate.  One way to know if it is the trim, once you are airborne, does it immediately require additional nose up trim?  Ideally, it should not require too much retrimming until flap retraction.  

[1980Mooney]

2 hours ago, rturbett said:

With the aircraft loaded well within CG, (two adults, 100lbs baggage mostly in back seat, some in the baggage compartment)  significant force is needed on the elevator to get the plane off the runway and into the air. 

an experienced mooney pilot tried, and noted how tough it was.

I'm looking for potential culprits- the only thing I have come up with is donuts on the nose need to be replaced (mains were done) and I'm wondering if that could lower the angle of attack enough to make us have to pull through it.

we thought the elevator trim indicator might be off- so we put a little extra up in- no real change, and clearly had to hold the nose down once we were in the air.

 

Any thoughts?

Thanks,

Rob

I have a hard time believing that compression of the nose gear donuts have much effect. I have a J with a Missile modification. It has an extra 200 lbs up front (and hanging out farther forward) on the same exact nose gear truss geometry and donuts as yours. Point being - my donuts/discs are always more compressed. 
 

Just dial in a lot more nose up trim. 

[Utah20Gflyer]

When I have a more forward CG I trim a little more nose up than the takeoff setting.  I’m not saying there isn’t anything wrong with the plane, but why not do some experimenting and progressively increase the nose up trim on a series of takeoffs and see what the result is.   If you get to a spot that feels nice and it indicates a lot of nose up trim that could be an issue with the linkage for the trim indicator.   When I say a little nose up I mean the bottom of the indicator line is at the top of the takeoff trim line.  So just a little bit.  
 

Trim setting should result in a reasonable airspeed once airborne.  I wouldn’t want to lift off and be really slow.  My setting gives me 80 mph which is great because that is the speed I want to raise the gear at. Positive rate -flaps up and then trim for 100.  

[Shadrach]

57 minutes ago, takair said:

Depending on what you are used to, the Mooney does take a little more pull for the initial rotation, due to training link gear.  At that point it is almost easy to over-rotate.  One way to know if it is the trim, once you are airborne, does it immediately require additional nose up trim?  Ideally, it should not require too much retrimming until flap retraction.  

My first input after take off is always to trim nose down a swipe.  My second trim input is to trim nose down after raising the flaps.

I am not buying the worn donut theory.  Something is not rigged properly and my first guess is the indicator. 

[Shadrach]

@rturbett  Does the aircraft begin to "wheel borrow" if you don't pull up?

[JayMatt]

1 hour ago, takair said:

Depending on what you are used to, the Mooney does take a little more pull for the initial rotation, due to training link gear.  At that point it is almost easy to over-rotate.  One way to know if it is the trim, once you are airborne, does it immediately require additional nose up trim?  Ideally, it should not require too much retrimming until flap retraction.  

This, high time Mooney pilots will probably think it's all kinds of other things because they are so used to it but it's just a Mooney thing. It's something I noticed on mine when I got it because it's so different from what I was taught on. I think the more hours you get in general the less you'll notice things like that. I bet it's just you getting used to Mooney and if your friend hasn't flown a Mooney in some time I would bet he's forgotten that trait. 

Like you said before, you tested the trim and it wasn't that based on needing to adjust after airborne. 

[Hank]

Does the J POH have similar verbiage as found in my Owners Manual? Yank it off the ground, then relax some of the pressure?

[Ragsf15e]

What flap setting do you use for takeoff?

start rolling with 5lb pull.

The loading you mentioned will be in cg but pretty far forward.  It is very noticeable.  Load center or aft cg and it will be so much better.

 

[Pinecone]

I noticed this on the first takeoff when I did my transition training.  For 2 people and average load, I set my trim to split the indicator on the nose up trim line.

Made all the difference.

[EricJ]

6 hours ago, rturbett said:

I'm looking for potential culprits- the only thing I have come up with is donuts on the nose need to be replaced (mains were done) and I'm wondering if that could lower the angle of attack enough to make us have to pull through it.

No, the landing gear suspension has pretty much zero to do with the amount of aerodynamic pitch rotational force required.

[M20F-1968]

It would seem that you should start with using the elevator travel boards to set a neutral position, then where you want the elevators to be for rotation.  When you are sure of that, then adjust the trim indicator for what take-off position should look like on the trim indicator.  I focused on a single line of the indicator since it is pretty sensitive and setting it in the middle of a wide range seemed too inaccurate and not repeatable.

John Breda

[A64Pilot]

I wouldn’t put anything into the trim indicator, meaning who knows or in truth cares?

Mine isn’t anywhere near the mark, it’s way higher. In truth I don’t remember where it is, it’s where I left it when I landed. I never look at the thing, if it’s nose heavy I trim up and tail heavy well you know.

For a data point, my elevator is dead even with the stabilizer when parked. 
See if yours isn’t, if it’s not close then maybe out of trim is an issue.

Assuming of course mine is normal and not an aberration.

Are most people’s elevator level? Note I’m not one of those who trims full up on landing, by landing with the same trim as takeoff, a go-around is no big deal trim wise.

[PT20J]

9 minutes ago, A64Pilot said:

Are most people’s elevator level? Note I’m not one of those who trims full up on landing, by landing with the same trim as takeoff, a go-around is no big deal trim wise.

It depends on the model. The elevators will be aligned with the stabilizer when the trim is set to takeoff on the models that have trim assist bungees. This would be up to and including the M20J. Beginning with the M20K, Mooney switched to a down spring and bobweight and the elevator rests full trailing edge down.

[Shadrach]

No matter what model you’re flying, you should have an accurate trim indicator 

[toto]

Just an additional data point..  My J does not require any unusual amount of force at rotation.  I almost always begin the takeoff roll with takeoff flaps and trim set to the center of the takeoff indication, and rotation force is maybe a bit higher than the Piper, but not significantly more.  As others, I would suspect a trim indication issue.  By the time the wing is generating enough lift to rotate, the gear won't be carrying much weight - I would not expect the pucks to make any difference at all.

[A64Pilot]

2 hours ago, PT20J said:

It depends on the model. The elevators will be aligned with the stabilizer when the trim is set to takeoff on the models that have trim assist bungees. This would be up to and including the M20J. Beginning with the M20K, Mooney switched to a down spring and bobweight and the elevator rests full trailing edge down.

Yes, I didn’t know that until one day I was taxing behind a long body and his elevator was hanging full down.

The title of the thread is Mooney J model, so I didn’t elaborate.

Previous owner changed the pucks on the mains, the nose looks fine and are I assume original to the airplane.

Unless the CG is much further forward on the big motor models I wouldn’t expect their to be all that much more weight on their nose wheel, after all the balance point should be close to the same. 

There is of course more mass and therefore more inertia so get one bouncing and I’m sure it would be worse than a lighter 4 cyl airplane.

[Tx_Aggie]

20 hours ago, rturbett said:

With the aircraft loaded well within CG, (two adults, 100lbs baggage mostly in back seat, some in the baggage compartment)  significant force is needed on the elevator to get the plane off the runway and into the air. 

an experienced mooney pilot tried, and noted how tough it was.

I'm looking for potential culprits- the only thing I have come up with is donuts on the nose need to be replaced (mains were done) and I'm wondering if that could lower the angle of attack enough to make us have to pull through it.

we thought the elevator trim indicator might be off- so we put a little extra up in- no real change, and clearly had to hold the nose down once we were in the air.

 

Any thoughts?

Thanks,

Rob

What you’re describing sounds normal to me if I don’t adjust the trim appropriately. It takes a few familiarity takeoffs but I set the trim indicator about one or two lines above “take off” for the takeoff and am usually adjusting it back down once airborne a few hundred feet. I think it’s just an airframe nuance. It also takes a lot of down trim to help with appropriate pressure for attitude control on approaches. Yes it’s different from the Cessna/pipers most of us came from but I’ll take those trade offs for the 25-40 knots faster in cruise speed on the same fuel flow any day! 1980 M20J

Edited January 9 by Tx_Aggie

[PT20J]

The Mooney main gear is fairly far aft because it is a trailing link design and it is attached aft of the main spar which is already pretty far aft due to the laminar flow wing design which has a maximum thickness farther aft than conventional airfoils. This means that Mooney's are "nose heavy" on the ground. In order to rotate for takeoff, this weight must be counterbalanced by a tail down force. The tail is a wing and the force is a combination of airspeed and angle of attack. Angle of attack is changed by elevator. Elevator force is a function of aerodynamic forces and pulling against the force of the trim springs and/or bob weight.

Takeoff trim setting is a tradeoff depending on personal preference.

1. It can be set somewhat nose up. In this case, almost no pull is needed to rotate for takeoff, but as the airplane leaves the ground it will tend to over rotate and a forward pitch input followed by a nose down trip will be necessary. Some prefer this.

2. Many of us prefer Mooney factory test pilot Bob Kromer's "Mooney pull" technique of setting the trim more neutral and beginning the takeoff roll with a pull on yoke, and holding that pull until the airplane rotates, and then releasing it as the airplane reaches climb attitude. This will require no trim change until the flaps are raised.

4. If the trim is set somewhat nose low, the airplane will not want to take off and may wheelbarrow unless a strong pull is exerted and then it will need nose up trim immediately to reduce the force for a normal climb out.

Skip

[rturbett]

All Great info- Thank you 

This airplane is new to me ( yes, I will accept congratulations and applause!) This represents a longtime dream fulfilled!

This likely has nothing to do with the nosewheel bushings, and everything with it being out of trim.  Will update you on findings  Just learned the previous owner set the up trim 1/4 to 3/8 above the mark to get it to come off at 70

I'm still looking for the link on where to add the map of where I've been in a Mooney- any hints?

Rob

[Fly Boomer]

1 hour ago, rturbett said:

All Great info- Thank you 

This airplane is new to me ( yes, I will accept congratulations and applause!) This represents a longtime dream fulfilled!

This likely has nothing to do with the nosewheel bushings, and everything with it being out of trim.  Will update you on findings  Just learned the previous owner set the up trim 1/4 to 3/8 above the mark to get it to come off at 70

I'm still looking for the link on where to add the map of where I've been in a Mooney- any hints?

Rob

Possibly the "About Me" section of your profile.

[Ragsf15e]

3 hours ago, rturbett said:

All Great info- Thank you 

This airplane is new to me ( yes, I will accept congratulations and applause!) This represents a longtime dream fulfilled!

This likely has nothing to do with the nosewheel bushings, and everything with it being out of trim.  Will update you on findings  Just learned the previous owner set the up trim 1/4 to 3/8 above the mark to get it to come off at 70

I'm still looking for the link on where to add the map of where I've been in a Mooney- any hints?

Rob

You really will feel a difference by putting some weight in the baggage compartment and using a more middle cg load as well.

Congrats on the new airplane!