Crosswind component + P factor

[201er]

I'm thinking about the amount of right rudder used on takeoff and crosswind takeoffs. Does this mean that you have a lower crosswind takeoff capability with a left crosswind than a right one? Is it substantial enough> How much right rudder as a % of deflection are we really using on takeoff?

[jetdriven]

At lower speeds with strong crosswinds it may take nearly full rudder to overcome the weathervane tendency on takeoff. Nosewheel steering helps out becuase a lot of weight is on it at lower speeds as well. P-factor isnt significant until you add AOA such as liftoff.

[Hank]

I'm thinking about the amount of right rudder used on takeoff and crosswind takeoffs. Does this mean that you have a lower crosswind takeoff capability with a left crosswind than a right one? Is it substantial enough> How much right rudder as a % of deflection are we really using on takeoff?

Nosewheel steering works well. My Owner's Manual says to keep her on the ground a little longer and lift off abruptly, because the plane will weathervane significantly in a strong crosswind. Seems like it starts as the nose is coming up, so the sooner all three tires are off the ground, the better. Then it can weathervane all it wants; just wing low into the wind and track the runway heading out the side window while clawing for altitude [and avoiding the parallel ridgeline at home].

I've never paid attention to how much right rudder travel I use, just that I use enough to get where I want to go. Something to pay attention to. Now I'll have to test full rudder deflection just so I know how much it is; based on taxi turns, it's an awful lot, much more than I recall having ever used in the air.

[N33GG]

In a Mooney, not much of a factor. And I know this is a Mooney forum.

However, if you ever fly a Globe/Temco Swift, it makes a HUGE difference. Due to P-Factor, you run out of right rudder with a left crosswind MUCH faster than you do with a right crosswind and left rudder. With a stiff direct crosswind, in a Swift, you better pick the right crosswind, even if it slightly favors taking off in the other direction, or you will be in the grass before you can say CRAP!

Well known in the Swift community, and tested only by a few fools. Don't ask me how I know that.

[John Pleisse]

P factor is considered in the demostrated component. One must also consider pitch attitude with P factor and WCA.

[Dave Marten]

201er, to answer your question, yes a left crosswind when coupled with asymetric disk loading (p-factor) more adversely effects available rudder than a right crosswind. For our nosewheel Mooneys the effect is much less of a factor than in conventional gear aircraft with rotation and liftoff being the critical point for us. Once climbing away, allowing the aircraft to crab into the wind will minimize the crosswind effects. Techniques like delaying rotation will increase airflow over the rudder (increasing effectiveness).

How much rudder effectiveness does a Mooney have? The demonstrated crosswind limit doesn't totally answer that question. A steady-heading sideslip in the landing configuration is the flight test technique that helps establish rudder effectiveness.

For crosswind certification requirements Part 23 sets the bar at 0.2 Vso (pretty low) leaving the manufacturer the option to test beyond. But they must meet 0.2 Vso for all approved takeoff and landing configs and loading envelope.

Why didn't Mooney go for more? Is there a best/worst case config? We can speculate all day, but we've got a demonstrated, published cross-wind value by which to safely operate our airplanes and base our decision-making on.

"2. § 23.233 Directional Stability and Control.

a. Explanation.

(1) Crosswind. This regulation establishes the minimum value of crosswind that must be demonstrated. Since the minimum required value may be far less than the actual capability of the airplane, higher values may be tested at the option of the applicant. The highest

90-degree crosswind component tested satisfactorily should be put in the AFM as performance information. If a demonstrated crosswind is found limiting, it has to be introduced in Section 2 information of the AFM.

b. Procedures.

(1) Crosswind.

(a) The airplane should be operated throughout its approved loading envelope at gradually increasing values of crosswind component until a crosswind equivalent to 0.2 VSO is reached. All approved takeoff and landing configurations should be evaluated. Higher

crosswind values may be evaluated at the discretion of the test pilot for AFM inclusion."

Know your aircraft limits, but more importantly know your own! Fly safe!

[Hank]

My Owners Manual does not list a a 'demonstrated crosswind component,' maybe because it wasn't fashionable in 1970. Always wondered if I needed to worry about it. Anything much over 10 knots cross component makes me more careful.

[Marauder]

My Owners Manual does not list a a 'demonstrated crosswind component,' maybe because it wasn't fashionable in 1970. Always wondered if I needed to worry about it. Anything much over 10 knots cross component makes me more careful.

I remember speaking with Bill Wheat from Mooney about how these crosswind speeds were determined. I wish I could remember the details of that conversation but it had nothing to do with some sort of formula, it had to do with the test flights and the amount of cross wind they experienced during the flights.

I know personally what my Mooney can do in a crosswind. I once landed after a flight in a 90 degree crosswind blowing a steady 25 knots. I remember it clearly because the CFII I was with was pushing on the rudder too. We were drifting ever so slowly and I think he didn't think i had the rudder completely in. I needed to land a little bit diagonally on the runway to knock a few degrees of cross wind. It was unusual since it was a steady wind, not the normally gusty winds you see when the winds hit that high.

[Lood]

As a rule, I follow my gut feeling in terms of a very strong cross wind take off. If it feels too strong, I take off from the opposite end (if possible) and this will have the P-factor assist me in directional control.

[sleepingsquirrel]

I've noticed the cross wind landings are far easier than the cross wind take offs. The fellow that sold me the Mooney told me that using a little brake can make the difference in stronger cross winds. I think the V tailed Bonanza pilots use this as well until the rudder is fully effective and the plane is just ready to fly. I've never needed to try this but have it filed in bag 'o' tricks just in case. Any one else heard of this?

[jetdriven]

Add power slowly in a V-tail in strong crosswinds and the takeoffs are easy.  The torque of a 300 HP IO-550 will drag you off the left side of the runway if you suddenly firewall it.

[Dave Marten]

Squirrel, The brake technique is valid of aircraft w/o or with marginally effective nose wheel steering. Common w/ tailwheels also. The nosewheel steering on your B should fill the bill till your rudder effectiveness kicks in. However, if you need a little tap of the upwind brake early in the takeoff roll to help keep your nose tracking centerline then use it (sparingly). A smooth power application will also keep it from getting to "squirrely"!

[RJBrown]

There are planes like the Grumman AA5 that have a castering nose wheel. They need brakes to steer on the ground. Our Mooneys do not need that technique. Reminds me of the time I sold my Mooney to a Grumman pilot. He was flying left seat and it was his first Mooney landing. Pretty good cross wind. I thought he was doing OK till at about 50 feet he called out "Your plane" He stepped off the rudders and I had to recover. Landed a little bit sideways and he stabbed the brakes to steer. Burned a new tire down to the cords. I could feel the flat spot as we taxied. I had to show him cords before we walked off. He tried to blame me till I showed him he was the only one with brakes. Brakes are not to controll direction in this manner too hard on the equiptment and not a lot of help. 

[jetdriven]

I used to fly a Liberty XL at  a rental outfit. It had no toe brakes, it only has a strange dual finger brake on the console. Now, on takeoff with a crosswind it was a squirrely beast. You have a castering nosewheel, marginal rudder at low speed, and you firewall it then let go of the throttle to modulate the brakes at the beginning of takeoff roll.  I cant believe they sold that thing as a trainer.