Mooney landing gear geometry and landings

[PT20J]

Ever notice how it's difficult to get the nose wheel to touch down softly when landing a J (my wife has ).  If I don't land with the nose real high, and if I get the back pressure just right I can get a smooth touch, but usually there's a bit of a thunk. I think I figured out why. I took some pictures of other retractables around the airport recently and I noticed that the Mooney main wheels seem to be a bit farther aft than others (hard to tell for sure without measurements). It's a combination of the trailing link design, the truss geometry and the aft location of the main spar (characteristic of a laminar flow wing). The logic goes like this: Just before touchdown, there is a certain tail down force that creates a balancing moment about the airplane CG. At the moment of touch down, the moment arm shortens since the pivot point is now the main wheels rather than the CG, but the tail down force doesn't change. This creates a nose down pitching moment. Or, maybe I'm wrong and it's something else. Thoughts, anyone?

Skip

[orionflt]

I have not had that issue unless I screw up and do a Cessna landing. IE: Stall it as the mains touch with the nose high. 
if I land on speed the nose is up but sets down smoothly as my speed bleeds off. 

Brian. 

[Andy95W]

Skip, I'm still trying to get my mains to not go "thunk" when I land.

[PT20J]

I should add that I haven't flown a C since the mid 1980's when I used to check out people in a flying club in San Jose CA. (N78888, cool registration, is still flying). It's been a long time, but I don't remember the same issue with it. But both the M20Js I've owned since have had a tendency to drop the nose on touchdown. I haven't flown a long body, but I did speak with a well known Mooney instructor at MooneyMax and he said that's just the way they are.

Skip

[Hank]

1 hour ago, PT20J said:

. . . . that's just the way they are.

Even my C is like that. Sometimes I roll the mains on, but unless I briskly raise the elevator a lot, it thumps down almost immediately after. Oh, well . . . . .

[EricJ]

I have the same thing happen sometimes, usually when I try to hold it off the runway too long.

When I bought my airplane the ATP/IA that had been working on it, and that originally ferried it to AZ from NV, told me to let it settle onto the runway and don't stall it onto the runway like a Cessna.   He had been maintaining the airplane for the previous owner, who had a prop strike with associated nose gear damage, he claimed because of porpoising from stalling it onto the runway a bit too hard.

It does seem to me that the landings are smoother if I don't try to hold it off, but let it settle with the nosewheel just a bit above when the mains touch.

I've had this airplane for a few years and over 300 landings and feel like I'm still just learning how it works.

[amillet]

Weight in the baggage compartment and nose up trim helps (sometimes). 

[PT20J]

Should have mentioned I’m usually at a forward CG - just me or me +1. But still...

[adverseyaw]

Yep, our mains are further aft of our CG than most other aircraft. This presents problems at low and at high airspeeds.

At low airspeeds, we need comparatively more elevator authority to keep the nose high than, say, a Cessna. I find it's harder to modulate at the edge.

At high airspeeds, above the stalling speed of the aircraft, it's really hard to get the airplane to stick to the runway unless you plant it on the pavement. Planting it means the airplane is descending (we'll say at 50-100FPM at time of touchdown) and the CG, which is way far out in front of the mains, continues downward after the mains touch, thereby causing the aircraft to pitch down and slam the nose before the descent is halted.

Anecdotally, I've observed that flying with pilots who land fast will tend to hit the nosewheel harder than those who land substantially slower. The geometry is what really gets you in the high-speed landing.

A by-the-numbers approach with touchdown right before stall results in the cleanest landings.

One advantage of having mains that far back: I've never seen a Mooney tipped onto its tail after a snowstorm.

[carusoam]

Location of the mains compared to where the Cg is... is the culprit...

Proof that all the Brand C and P on the airport don’t have this challenge....

Wait for heavy snow... look to see which planes are pointing skywards...

None will be Mooneys...

 

Things that help...

1) Speed control... 10kias fast is bad...

2) Power control...  1kfpm is bad...

3) Long runways...  floating in ground effect slowly wearing off the excess air speed makes you look like a patient genius.

4) Shallow approaches... a couple of hundred fpm is more controllable...

5) AOAi(s)...  a fancy way of showing up at the threshold with the right amount of airspeed for the weight and configuration...

6) Only count the landings on Sundays... more recent practice, you are warmed up from Saturday...

7) Saturday landings are not as good... Rust still on...

8) Sending the Cg back some can help... tools in the back... improves your arm control over the yoke...

9) Use T/O flap setting works too... less drag... less change to counter...

10) leave a touch of throttle in... keeps things from slowing rapidly... or descending rapidly...

11) Cut back on anything that adds to increased changes in energy states... No MP, max flaps, high approach...

12) if the plane is slowing rapidly, it will be an extra challenge to get the attitude just right to settle on the mains while holding the nose up...

13) Too much speed... you go and put in the attitude for a soft landing, and you get a ballon instead...

14) not enough speed... you go and put in the attitude for a soft landing, and the plane stops flying a foot off the pavement...

15) When you are well practiced... all of these things come together naturally.  That is why Sunday landings are better than Sunday... Rust actually sets in between Monday and Friday... it takes Saturday to get it knocked off...

16) nicely lubed, not sticky, yoke controls helps to modulate the control inputs...

 

Looks like I copied Adverse’s post...
 

PP thoughts only, not a CFI...

Best regards,

-a-

[PT20J]

I get the best landings with full flaps crossing the threshold at 65 KIAS, with a little bit of power all the way down to the flare, then round out slightly nose high while simultaneously reducing power to idle. If I get the timing right, it settles on the mains and the nose wheel isn’t high enough to hit very hard. I’ve found it almost impossible to land with the nose very high and control the descent of the nose with elevator consistently. Worst landings are in the summer with a hot runway emitting thermals. 

The AOA on my Aspen PFD is really too small and it needs calibration.

Skip

[carusoam]

See if @201er is around for landing insight...

Mike has been successful at separating the the mains touch down, from the nose wheel...

Mine happen about a microsecond apart from each other...

If you watch Mikey’s videos... there is probably a whole second or two between the two events...

Best regards,

-a-

[larrynimmo]

When I learned how to fly my mooney virtually all landing were “power off” and if timing wasn’t  just perfect, landing could be more abrupt.   With a different instructor while ifr training, he suggested I do ”power on” landings.  With  just a little use of power all landings grease.  The key is to cut power once you touch down or there is too much energy keeping the plane able to fly if bumped.  It does add a little to your distance as you have a very slight landing float.

[Bob - S50]

In almost 7 years, I've had 2 landings during which the nose did not drop immediately after the mains.  Don't know why.  Maybe because I finally attained a high enough pitch attitude at touchdown to rotate the wheels further forward.

If that's the case, and provided you have enough runway, you might try a couple no flap landings.  Those will require a higher pitch attitude at touchdown.  That will rotate the wheels forward relative to the CG.

[ragedracer1977]

I can wheelie down the entire 4500' runway at DVT.  Full aft trim, land with just a touch of power and hold the yoke full aft.  Little modulations of power and yoke and you can hang the nose in the air as long as you want.  It's fun when the pattern is empty (almost never lol!). Otherwise they get sort of annoyed if you don't exit immediately

[gsxrpilot]

Contrary to what some others have said here, my smoothest landings are when I have a little extra speed. I was demonstrating soft field landings the other day and was able to roll it on the mains, keep the nose wheel off for 1000 to 1500 ft and then smoothly lift back off again without the nose wheel ever touching down. This was no flaps and a little fast. 

YLMV

[MooneyMitch]

Careful you all....... other brand types may be covertly reading MS posts ..... you’re hinging on giving credence to the MYTH that Mooneys are difficult to land !! 

[gsxrpilot]

1 minute ago, MooneyMitch said:

Careful you all....... other brand types may be covertly reading MS posts ..... you’re hinging on giving credence to the MYTH that Mooneys are difficult to land !! 

Clearly Mooney drivers are all just superior pilots. 

[MooneyMitch]

39 minutes ago, gsxrpilot said:

Clearly Mooney drivers are all just superior pilots. 

Well, yes, of course we are........ present company included 

All seriousness aside, all my landings in the C, E, F and R’s have been superior  !!! 

[Austintatious]

Here is a  couple of pennies....

When the gear is aft, you do not want to be increasing your pitch as you touch, this drives the gear downwards and makes for a harder touch.   In the              Gulfstreams this is VERY pronounced.  In fact, in lots of jets a very smooth touch can be achieved by pushing the nose down at the last second, when you think the gear is about 1 foot from the ground... This lowering of pitch results in the air frame descending, but the main gear is going " up" in relation to the air frame and DOWN very slowly to the ground.  DO NOT DO THIS IN THE MOONEY.

 During the round out, I am very slowly and smoothly reducing power to idle.  I find my smoothest touches are when I hold my attitude constant... Not increasing attitude as I touch down.  I cant always do that of course, especially when it is gusty, but when I can she greases on.

[Austintatious]

1 hour ago, gsxrpilot said:

Clearly Mooney drivers are all just superior pilots. 

Probably,  although the amount of Moonies that have had prop strikes is staggering.  One would think it is difficult to keep the nose up on landing!

[MooneyMitch]

6 minutes ago, Austintatious said:

Probably,  although the amount of Moonies that have had prop strikes is staggering.  One would think it is difficult to keep the nose up on landing!

It’s not difficult.... in fact it’s correct and it’s fun!! 

[Austintatious]

34 minutes ago, MooneyMitch said:

It’s not difficult.... in fact it’s correct and it’s fun!! 

It was a tongue in cheek comment...  Of course it is... but for some reason, a LOT of mooneys have had prop strikes.

[MooneyMitch]

2 minutes ago, Austintatious said:

It was a tongue in cheek comment...  Of course it is... but for some reason, a LOT of mooneys have had prop strikes.

Yep, I knew that. 

[RobertGary1]

I've not found a way to full stall land on the mains and not thunk the nose a bit, especially when forward CG. The taildragger pilot in me will not allow me to be sloppy and fly it on. That was a challenge on my first type rating since holding the plane off in the flare is a giant no-no in jets.

 

-Robert