CT Landing Characteristics

[WestCoast]

I came across this post on a US CT owners forum which I thought might be of interest to current and/or future CT owners as it explains certain characteristics of the CT during approach and landing.

 

(The author is a retired US Navy aviator and engineer and a current CT owner.........I obtained his permission to post this here)

 

Quote

 

The mean aerodynamic chord (MAC) of the wing is a line drawn from the leading edge to the trailing edge.

 

Assume a CTsw cruising along at 80 kts, say, with flaps up. The angle of incidence has been chosen by the manufacturer and is fixed. The pitch angle has been set by the pilot to hold the altitude and the angle of attack is that which results.

 

Now, lower the flaps to 15 degrees. Redraw the MAC from the leading edge to the trailing edge of the flaps. In effect, the angle of incidence has been increased. To maintain a reasonable angle of attack, the pitch angle must be lowered. Said another way, lowering the flaps results in a flatter pitch angle. Lowering the flaps more and more results in lowering the pitch angle more and more.

 

In the CTsw, this effect is particularly pronounced when compared to most other aircraft. At 15 degrees of flap, as at takeoff, the pitch angle which just barely raises the nose wheel off the ground is correct for lift off. This is a relatively shallow climb angle compared to most aircraft at take off. Raising the flaps and assuming a 70 knot airspeed for climb results in an increased pitch angle as the above would suggest.

 

If one selects 30 degrees of flap and reduces power at the base turn, the pitch angle is very much below the horizon to keep 55 knots. In fact if the engine is at idle, the nose down attitude is rather striking and surprizing at first, compared to most other aircraft. The touchdown angle is, according to this theory, also flatter than it is for 15 degree flap landings. For this reason, the change of pitch angle in the flare for 15 degree flap landings and approaches is much less than that for 30 degree flap landings. The approach and touchdown angles for a 15 degree flap landing approximates that of most other aircraft.

 

However, the transition from final to touchdown at 30 degree flaps must be learned in the CTsw. It isn't difficult, it is just a bit different. The 30 degree flap approach angle is fairly steep and the landing pitch angle is fairly flat, with nose wheel just barely off the ground. Increasing pitch angle too much by holding the plane off the ground can cause it to abruptly drop...this is just fine if you are just inches off the ground, but not so good if you are high.

 

I suspect that a part of the explanation for the more dramatic effect of flaps on pitch angle in the CTsw is the fact that essentially the flaps extend across the entire wing since the ailerons droop as well as the flaps. Flaps cover only about half the wing in other aircraft, so the effect is less dramatic.

 

Now, it follows that the landing pitch angle for a 40 degree flap landing will be flatter yet. In fact, it will be very very flat, almost three points. We (correctly) don't want the nose gear participating in the landing shock so we will naturally try to get the nose a bit higher and face the real possibility of a drop out. Again this is OK if you have skillfully got the gear a few inches off the ground, but very bad if you are a foot or more in the air. Recovery isn't easy with the drag of 40 degree flaps. Getting it right is a lot easier if a little power is carried.

 

My advice for new pilots is to learn the CTsw using 15 degree flaps for takeoff and landings. When that feels comfortable, do a lot of slow flight at the other flap settings and then work on the 30 degree flap setting landings. Only later, when your skills have developed and you want to study short field landings, work out your technique for 40 degree flap landings. Or not. The only reason I can think of to do a 40 degree flap landing is for short field work and I am not sure it would help much there. For gusty conditions and/or crosswinds, use either no flaps or 15 degrees only and increase speed. Increase speed by one half the gust value. In gusts, get set up with a little power on (and hand on the power) and cruise down the runway fishing for the sweet spot.

 

For ample runways, a little power on any final approach generally makes smooth landings easier, but you should practice power off approaches and landings regularly to be ready for the day when there is no choice in the matter.

 

 

[slartibartfast]

Post moved

 

LeoSAA - I moved your post in this thread to the "Disgusted with Narromine" thread where it belongs.

 

Ross