A/C veers left *more* upon rotation

[Skywarrior]

Hello, all -

Still trying to master my new beast (M20M).

On takeoff roll, I have max right rudder trim dialed in, plus I press on the right rudder pedal. We barrel down the runway, tracking along fairly straight.

So far, so good.

At 60 kts, I pull back slightly to lighten the nose. Immediately, the aircraft starts heading for the infield grass. I push harder on the right rudder pedal, without much noticeable effect.

Do I need to just press *even more* ??  I don't *think* that I'm touching the left brake.

It's unsettling that I can't get it to do what I want it to do.

 

Chuck M.

[carusoam]

Chuck,

That seems very unusual to me.  I have the long body M20R wtih the N/A Continental IO 550. 

Rudder trim set to take-off.  No unusual struggle or even noticable tug during rotation.....

Time to check the basics, air pressure, unusual tire wear, brake sticking.  See if the rudder trim is attached to anything or operating properly.

or Maybe this is an M20M thing???  there are a few M20M guys here too......

Best regards,

-a-

[Parker_Woodruff]

Sounds like P-Factor is doing it's usual job.

But if there's a control issue with the airplane, it needs to be resolved.  How much left rudder are you putting in a fast, steep descent?

[KSMooniac]

The nose gear might be damaged or mis-aligned.

[roundout]

Quote: carusoam

or Maybe this is an M20M thing???  there are a few M20M guys here too......

 

[DaV8or]

I have to chime in on this one because I almost started a similar thread myself.  I have a M20F and I have been having the same problem. There's lots about landing a Mooney, something I think is a non event, but this is the only plane I have ever had trouble taking off. After lots of head scratching, here is what I've done so far with good results:

1) Set elevator more trim down. (a little below the "take off" mark)

2) Hold the plane on the runway longer and build up a bit more speed.

3) Just as you feel the nose wheel leave the ground, smoothly add more right rudder.

The theory:

The Mooney has a weak rudder with limited authority. The plane sits low to the ground and has a very efficient wing. The nose wheel is connected to the rudder pedals. These things lead to an airplane that jumps into ground effect before the rudder has any much effect. The nose wheel keeps the nose going down the centerline, but once it lifts off, P factor over powers the weak rudder and the plane skids off to the left.

By keeping the plane on the runway longer and building up speed, gives the rudder more authority to deal with the P factor when nose wheel does break free. Adding more rudder at the time of rotation counter effects the P factor. The connection between rudder and the nose wheel makes this problem happen in the Mooney. If it had a castoring nose wheel I suspect this phenomanon would not happen. If it had a bigger rudder, it would behave like a Cessna or Piper and the problem wouldn't happen.

I might be full o' crap, but it's working for me so far.

[Gone]

Hi all:

I have to report to you that I do not experience this phenomenon on take off.  '65 E model.  Whatever it is, it would scare the living Beejees out of me.

[Cruiser]

just add a little right aileron like you do for crosswind takeoff. My guess is you are not using enough right rudder. 

[flight2000]

I agree with the others that there is something more going on with the aircraft.  My E basically flies itself off the runway when it's ready and I have not come across any of the described characteristics mentioned above.  I've flown in other C and E models and not experienced them either (I'm up to 6 right now).  I'd have an experienced Mooney mechanic look at it.  The p-factor in a 200hp engine is going to be minimal at best (still there, but not as much as the bigger HP M and R models).

Brian

[Piloto]

Looks like you may have a rudder linkage problem. On the long bodies yaw control is better than on previous models. My advice;

1. Check rudder play by trying to move the rudder surface on the ground. It should not move more than 1/2".

2. With the towbar rotate the nosewheel left an right and verify that the rudder follows the nosewheel.

3. Have someone inside the plane that can push on the rudder pedals.  Lift the nosewheel by having some one (200 pounder) lean against the horizontal stabilator/tail root. Push on the rudder pedals and check for equal deflection.

4. Check the rudder push rods links and brackets. You may have a crack bracket that only shows when the rudder is pushed to the right.

5. Almost forgot this one. Check for bent push rods. It is not uncommon on planes exposed to strong high winds on the ramp.

DO NOT FLY THE PLANE UNTIL THE ABOVE HAS BEEN CHECK. Rudder flutter can take the tail off in a matter of seconds.

José 

 

[Skywarrior]

From DAV8OR -

I have to chime in on this one because I almost started a similar thread myself.  I have a M20F and I have been having the same problem. There's lots about landing a Mooney, something I think is a non-event, but this is the only plane I have ever had trouble taking off. After lots of head scratching, here is what I've done so far with good results:

1) Set elevator more trim down. (a little below the "take off" mark)

2) Hold the plane on the runway longer and build up a bit more speed.

3) Just as you feel the nose wheel leave the ground, smoothly add more right rudder.

The theory:

The Mooney has a weak rudder with limited authority. The plane sits low to the ground and has a very efficient wing. The nose wheel is connected to the rudder pedals. These things lead to an airplane that jumps into ground effect before the rudder has much effect. The nose wheel keeps the nose going down the centerline, but once it lifts off, P factor over powers the weak rudder and the plane skids off to the left.

By keeping the plane on the runway longer and building up speed, gives the rudder more authority to deal with the P factor when nose wheel does break free. Adding more rudder at the time of rotation counter effects the P factor. The connection between rudder and the nose wheel makes this problem happen in the Mooney. If it had a castoring nose wheel I suspect this phenomenon would not happen. If it had a bigger rudder, it would behave like a Cessna or Piper and the problem wouldn't happen.

Dave: I think you've hit it on the head. My instructor tells me I'm trying to rotate too early (60 kts). Next time, I'll be easier on the yoke and keep a heavy right foot.

I'll report back after I try it.

 

Chuck M.

[jlunseth]

I don't really ever "rotate" at a specific speed with any plane.  I wait until the plane tells me it is ready to fly, and then unless there is some specific reason (i.e. short field and trees), I just gently help it lift off.  The speed where my plane likes to fly is somewhere in the mid-60's, a little under 65 on most days and at most elevations.  I have found that the nose trim issue with Mooneys is just the opposite of what you have said.  They like to get up on the nose gear, so a little more trim up than what is marked for takeoff works better.  But each plane is a little different, and maybe yours is telling you the CG is back pretty far, to trim nose down a little.

Also, the tail authority on a Mooney is actually pretty good.  They are fairly well known for their ability to make crosswind landings with alot of crosswind.  Of course, on any aircraft you are going to have less authority with any of the control surfaces at low speeds.

I would definitely heed Jose's advice though, and check the rudder out. 

[Skywarrior]

OK, I went out tonight and made a flawless (well, much better than before) takeoff right off the bat. I left the nose alone, except for a little nudging of back stick. It rolled straight, and when it start acting really light on its toes, I gently coaxed it off the ground.

 

Thanx for all the advice. Turns out it was simply pilot inexperience.

 

Chuck M.

[richardheitzman]

As well as the higher rotation speeds, I chant to myself "keep your heels on the floor" which keeps your toes off the brakes, works well on landing too.

[Skywarrior]

Yes, that is good advice, unless you have Size 14 feet, like mine.

I have to flex my feet back - hard - to keep them off the brakes - even with my heels on the deck.

 

Chuck M.