Saturday, January 26, 2008

Steep turns and compass turns

Now that I have demonstrated sufficient proficiency in crosswind landings to be allowed to fly solo to the training area, I can get on with the other remaining lessons for the GFPT.

According to the Redcliffe Aero Club syllabus, I still need to do compass turns, precautionary search, maximum performance circuits and two hours of instrument flying. Plus a couple of hours of solo airwork in the training area. If everything goes according to plan, I should be able to get all that done within the next two weeks. Fingers crossed.

On Wednesday I went back to the training area with Lee to practice compass turns and steep turns. I had already done one session of steep turns two months ago. What I remembered was that steep turns with 45 degrees angle of bank were no big problem, not really different from a 30 degree turn really. There was however a lot more difference going from 45 to 60 than there is from 30 to 45.

At 60 degrees I really had to pull the control column all the way back to maintain a constant altitude in the turn. The acceleration experienced in the frame of reference of the plane is 2 G. I could feel the skin on my face, especially the cheeks, being pulled downward. In one turn I tried to raise my right hand and it really felt twice the weight. I know, this shouldn't come as a surprise, but as always it's one thing to read it in the book and another thing to experience it in the plane.

This time it all went a bit more smoothly then the first time. I did well at maintaining altitude within the required 100ft margin for a full-circle steep turn. This despite the fact that the horizon was hard to find on that day. Lee noticed that I didn’t wait for the nose to start falling before pulling the control column, I’ll try to work on that when I go solo. We also discussed how much power to add in steep turns in order to keep a good safety margin between us and the stall speed. I was not consistent enough however with rolling out within 10 degrees of the target heading, so that’s also something to work on.

Compass turns were rather uneventful. As long as you remember the ONUS (Overshoot on North and Undershoot on South) and SAND (apparent turn South when Accelerate, North when Decelerate) rules that apply for the Southern Hemisphere, then it’s just practice.

The nice thing in Redcliffe is that because of the 07/25 orientation of the runway, the compass error linked to acceleration is very obvious when accelerating on take-off. With the nosewheel on the centreline for a take-off on 07, the compass swings well past East in the few seconds after applying full power.

It probably is also quite obvious when decelerating during a short-field landing, but keeping the plane going straight while braking keeps me busy enough to not have had the opportunity to stare at the compass so far. What's also quite likely is that on landing the various shocks and vibrations will prevent an accurate reading of the compass.

Lots of flying booked for the next weeks. Getting up at 4:45 twice this week was hard, but I’m happy I did it. Booking lessons within a few days of each-other really helps with not loosing the feel for the plane, but that may turn out to be a costly habit in the long run :-)

No comments: