Flaps In my M20S Don't Like Me

[docket]

After 250 hours in this plane I can reliably squeak 95% of the landings (no one's perfect) at 15 degrees of flaps (first notch) but give it full flaps with a lot of trim and I still seem to be fighting the nose wheel.  At first I thought I was not getting full range with the trim but we have checked that.  Mine is the Screaming Eagle 310HP conversion so there is a 20lb weight increase on the nose.  I have a tendency with full flaps with just me on board and 70% fuel to set the nose on the ground almost simultaneously with the mains.  If I have a decent load, or backseat passengers then it is no big deal to use full flaps because it helps move the CG aft. 

A few weeks ago I also managed to put the nosewheel down first and get a nice bounce when I came in full of fuel after a short maintenance flight.  I have about 1500 hours so I don't think it is because I am new to flying.  I always use Class B Airfields with long runways so I have resorted to landing with 15 degress of flaps as it gives me reliable landings.  I know that the POH says full flaps but I have gotten tired of the landing fights.  I am curious if anyone else is landing with 15 degrees or if I am, for some reason, just not in sync with the airplane.  I came from a Bonanza in which I could squeak a landing with my eyes closed. 

[GeorgePerry]

First let me say I LOVE the M20S...It’s my favorite Mooney model.  After my military retirement and I save some scratch I’m going to have one.

As for your issue:  It sounds like you might have a W&B problem?

When the shop installed the screaming eagle conversion (NICE!!) they should have performed a complete weight and balance using scales and not just updating your old info.  If they didn't that needs to be done.  The next time the plane goes in for maintenance have your shop do a completely new W&B and make sure they actually weight the plane using scales.  This is important because you have to find out what the weights are on each wheel.  They will want to pay particular attention to the total weight that rests on the nose. 

With that said...Assuming your W&B info is correct then your going to want to get in the charts and see what your W&B is with you and a normal fuel load.  If your CG is right on the forward edge - but still inside the envelope, normal landing techniques with Full Flaps should be more than adequate to get the mains on well before the nose.  

Here's what I suggest and I apologize in advance if I'm talking down to you but....Full Flap FWD CG landing technique requires running the trim full nose up and holding the yoke nearly full aft prior to touchdown.  This is especially true in long body Mooneys.  My recommendation for trimming on final is that you should have a slight nose up pitch already dialed in.  That way when it’s time to flair it doesn’t require a lot of effort.  As the plane slows just above the runway, the trim will become neutral again just prior to touch down.  If you’re already doing this and still getting 3 point landings you might very well have a CG problem.  If the CG is forward of the forward limit, as the plane slows the elevator looses effectivness and the problem becomes exagerated...thus the 3 pointers.

A word of caution...nose first landings in Mooney can get ugly in a hurry and become VERY expensive if not handled immediately in the correct manor (read prop strike).  If it does turn out that the CG is “a little” too far forward that's a fairly easy fix by repositioning some weight.  Your MSC will know what they can and can’t move aft without a lot of paperwork.  Also if you don’t have a skytec starter, I’d recommend getting one installed.  It’s a great upgrade and a very inexpensive way to get ride of some FoFW weight.  Either way I would treat this issue with prudence and respect.  Find out what the problem is and address it immediately.

Hope this was helpful

Good luck

 

[TurboExec]

I've run into similar problems with getting the nose up when flying solo with lots of fuel.  I usually throw a case of oil in the back when I'm going solo and that helps tremndously in the flair and really making the landings smooth.  Go along with what George said.....and if you have the room there is no need for using flaps at all in a Mooney, there really isn't a whole lot of difference except in pitch attitude of the aircraft and that is where you are having trouble when you have a forward CG.

[Piloto]

Docket the problem you describe is not unique to the long bodies, it also happens on the short bodies too. It is related to the proximity of the wing to the ground on touch down. Because the wing is so close to the ground it tends to build an air cushion with the flaps extended that tends to keep the plane a float thus causing a small lift amount that causes the plane to bounce on ocassions (speed and weight related). The problem is agravated when landing on gusty or crosswind conditions. To agravate things the center of lift moves back when the flaps are extended thus causing a nose down condition. One solution to the problem is to trim (hands off) on short final at no higher than 70kts with full flaps. This works if there are no gusts. But if there is a gust at touchdown the plane most likely will bounce. My prefered solution is to approach with full flaps at around 75kts and then just before touchdown (5 ft from ground) raise the flaps completely. This will eliminate the floating and bouncing effect even under gusty conditions. As the flaps raise the nose will raise assuring a mains only touch down. With this procedure I can make consistent soft landings with minimum ground roll. Try it, you will love it.

José

 

[docket]

I put the plane on the scale and my CG has moved forward about an inch.  My plane does have a few extra items on the nose that make it a little heavier than the average bird (i.e. the 3 blade and the AC compressor).  I have concluded that if I am approaching solo with more than 50 gallons on board that partial flaps just seems to handle better for me.  I flew a friends J model and the short body clearly handles much better with full flaps.  With that said, add a passenger or put some weight in the tail the issue goes away entirely.  Eric

[GeorgePerry]

Glad to hear you've determined the root cause.  Just out of curiosity, are you within the fwd limits of CG envelop when the plane is adversely loaded?

The 1/2 flap option is certainly the easiest method of dealing with the issue, but you might want to consider relocating some weight.  Now you have the exact WT&Bal info for your plane it’s easy to calculate how much weight and how far it needs to move to get things back into balance.  That way the fwd CG issue would be fixed for the entire flight envelop...and would provide for a more permanent solution.

Good luck

 

[alun]

I too am having trouble nailing my landings in my M20J.   Half flaps seem fine, full flaps i've had a couple of bounces followed by my first ever go around!   What's the knack!?

al.

[TurboExec]

Yeah if you are bouncing you are coming in to fast or flairing to high.  Just hold the nose up and let the airspeed bleed off and the plane will "fly" itself onto the runway.  Don't try and land a Mooney like you would a cessna

[The-sky-captain]

Alun-

Ditto on the above responses about coming in to fast. The two big bounces that I have experienced have happened in windy conditions when I brought the plane in a little hot. Good luck.

[The-sky-captain]

Just wondering if you guys follow the POH and always take off with 1/3 flaps? I think it was Bob Kroemer, the Mooney test pilot, that stated he usually doesn't use the flaps unless he is on a runway of less than 3000'. I have experimented with it both ways and think that that following the POH is the way to go for me. It does get off the ground alot quicker which is always good:)

 Also what about flaps on crosswind landings... I know the POH says full flaps but it seems with a stiff crosswind pushing the limits it would be easier to land with partials. My CFI always drilled into me to fly the plane like the POH says. I would like to see what you more experienced Mooney pilots think about the issue.

[triple8s]

Thank God I'm not the only one that still has those embarassing landings sometimes. I have been flying Cessnas for years and got a Mooney last spring, now with about 50 hours behind me I still sweat the landings. About 3/4 of the time they are ok, but throw in some crosswind and a short runway and well we all know what can happen. I am hesitant to go on trips if I even think there will be a x-wind. I hate that because my bird is a real x-country machine with O-360 and long range tanks it's perfect for traveling but I have yet to "nail" the landings. Sometimes they are greasers and sometimes they're a humbling experience. I have learned this, the KEY to landing my M20c is airspeed on final, 75-80 over the numbers or it will be very interesting, and the most important thing, after the second bounce, its firewall it and go around cause the third one will usually get the prop, or so I'm told, I go around.

[Mooney_Allegro]

I also use takeoff flaps in the M20J for departures, and full flaps for landings on a normal basis, even with crosswinds.  If the winds are too strong, I just don't fly that day.  I do make sure if the winds are strong, I position the controls properly on the taxi out/taxi in, and position the controls into the wind on the takeoff roll, and gradually remove the correction as the plane accelerates. 

[TurboExec]

No flaps for takeoff unless I'm at/near gross or short field, otherwise I notice no significant difference with the flap setting.

[Cruiser]

Check the CG for your typical flying conditions. IF you are alone it is probably pretty far forward (<45in for M20J). The nose of the Mooney wants to come down fast after the mains touch. It is really hard to keep it up. With even a small amount of excess speed, this initial nosewheel contact will make the nose bounce up and send you back into the air.

Make sure you have the airspeed below 80kts. and trim it back. When the stall horn goes off, try really hard to keep the nose up and the nosewheel off the ground. Do you have the yoke in your belly after the mains touch the runway?

You can always add some weight to the baggage area to move the CG back.

[GeorgePerry]

The POH is a great guide but as one gains experience and knowledge I believe that it’s OK (even recommended) to deviate slightly as needed for conditions not specifically addressed in the POH.  The POH can’t be written to cover every specific scenario.  It is designed to provide guidance and procedural recommendations that clump a wide range of situations into a one size fits all methodology. 

For landing flap settings some concepts that make Mooneys unique when compared to other more mundane types of aircraft:

On final approach, by comparison, Mooneys are airspeed sensitive.  They use a laminar flow wing design that allows for great cruise speeds and good overall handling thought the envelope.   C’s and P’s typically use a conventionally shaped airfoil that tends to be optimized for landings and not cruise.  Because of this Mooneys must be flown precisely for consistent results.  In order to dispel any fears let me repeat...Mooneys are not hard to fly – but must be flown precisely for consistently good landings.  If the approach is too fast then the excess speed must be depleted in ground effect and the flare prior to touch down.  Otherwise a bouncy landing is likely.  This excess airspeed takes time, a little skill and adds significant distance over the ground to bleed off.  For landings this is my Rule-of-thumb:  Each extra knot of unnecessary airspeed equates to a 100 foot increase in landing distance.   Since Mooneys tend to be sensitive to small airspeed excursions on final, they are proportionately sensitive to gusty wind conditions.  Gusty winds require a slightly higher than normal approach speed to compensate for airspeed decay due to a tail on gust. 

For Gusty or high cross wind conditions ½ flaps offers some advantages and disadvantages to full flaps.  Pro’s – ½ flaps is a good compromise between reduced approach speeds and drag needed to keep the approach angle adequately steep.  Also under a nose on gusts, ½ flaps tend to make alittle more lift than drag.  Full flaps under a nose on gusts tend to make a little more drag than lift.  With out getting into a beeps and squeaks discussion of the L/D drag curve, suffice to say that ½ flaps tend to provide a more predictable approach in terms of airspeed control and flare dynamics than full flaps.  As with everything related to airplanes you don’t get something for nothing.  Landing with ½ flaps will require a slightly higher approach speed and proportionately longer landing roll. (Remember the 1 knot = 100Ft ROT)

Full Flap landings in Gusty or high Cross wind conditions is by no means impossible or even difficult...they just require a bit more diligence to airspeed control and angle of attack management.  Gusts Tail on and head on have more pronounced effect on maintaining a stabilized approach.  Tail on gust cause reduced overall lift more dramatically than a ½ flapper.  And a head on gust causes a quick lift increase followed by a rise in induced drag due to the fact that the aircraft is operating at or near L/D max.  Any increase in AoA will cause drag to rise more quickly than total lift.  On the good side, FF landings allow for shorter landing roll of course.

If you’re still awake, the simple rule of thumb, if landing distance isn’t a concern, ½ flaps is a good way to go if it’s gusty or you have high crosswinds.  If landing distance is a concern then consider using FF. 

For Take offs, I always use slightly less than ½ flaps.  Gets the plane off the ground more quickly than a no flapper and doesn’t cause excess drag slowing acceleration in ground effect. 

Typical technique is rotate, maintain a gradual positive ROC but allow the aircraft to accelerate in or just above ground effect until VY then increase ROC to capture VY or VY+5 for cooling and visibility. Once desired climb airspeed is reached and obstacles are cleared, Flaps come full up.   As for gear, I’m not in the leave it down until you can’t re-land on the runway.  I retract the gear after takeoff regardless of the runway in front of me.  Lots of folks will take issue with this but it’s my technique.  My thought is that if the engine quits I could care less if I belly the bird in or not...at that point all I care about is gliding someplace safe.  Gear hanging in the breeze reduces those options.  Also that’s why I pay my insurance premiums.  I don’t care about the bird, just walking away from it when the landings over.

[TurboExec]

Quote: JimR

 At least in the C model that I fly, takeff flaps make a noticable improvement in that they make it easier to get the gear up before the aeronynamic loads increase to the point of making this difficult.  Interesting that that's not an issue for you, Adam.  Perhaps it's in the way that the gear is rigged. 

[alun]

thank you for the advice.  will put them into practice and see what works for me.   it is noticable that the plane needs a lot more attention and planning to stay ahead of it than compared to the pipers i learned on.

al

 

[MooneyPilot231]

I have given up on two things... taking off with flaps down any at all, and landing with more than half flaps. Taking off with flap at t.o. position causes the plane to suck to the runway and I have to kind of jerk the yoke back to get it off the ground. I can land with full flaps but half flaps allow me to keep flair/ground effect time to a minimum. I will brag and say that I squeak most of my landings but keep in mind I fly my plane 3-4 times a week. Once the plane has settled near the runway I hit the up trim button and it slows the decent to make almost every landing perfect. Taking off I keep the trim indicator just above the area designated for take off. (you might start with it in the upper part and experiment from there) With neutral elevator the plane very slowly leaves the runway at about 70kts with no input from me. Your plane is different but maybe some of this will help....

I also agree with George on getting the gear up asap. If that engine quits above the runway you are not going to land on the airport unless that is one hell of a long runway!