Roger that, on Ted's and Brett's posts. I have come to have some doubts about that old saying, however. Practising errors can't help. Practising to compensate for an out of trim airplane won't help. You can't trim in turbulent conditions, and I can't see anything to be gained from practising in that stuff, unless you are only trying to get experience flying in those conditions. Probably not for every skill level, huh? I'm just sayin' that sometimes you can get something from practise, and sometimes you can't, so don't. Some of my more progressive days have been when I was out all day and spent a lot of time in the lawn chair between flights, thinking about trim changes or what I was doing wrong. 
Steve
Hi Steve,
I'm about 98% in agreement with all of the above. The only area I would dispute would be the value of flying in bad air (with realistic limits, of course). I would never suggest doing this routinely but--especially for someone learning the value of proper trim and how to go about achieving it--flying in bad air can go a long ways towards learning the efffects of proper trim.
The single most important thing that can be learned by flying in high winds is how important it is to have the CG in the "right" place. The question then, of course, is what do I mean by the "right" place.
In stunt heaven air an airplane can be balanced almost anywhere it can fly stably and still be "trimmed" to fly award winning patterns. (The exception, of course, is that a tail heavy ship will never fly well). Within reason a straight stunter of reasonable weight that is nose heavy can have control deflection and handle line spacing adjusted so as to allow acceptable cornering. It won't be technically optimum but, for what we do, such a ship could win a lot of contests with a good pilot at the handle. The temptation would be to say the CG was "right" because of those trophies.
When flying in the wind, however, such a ship will rapidly travel down the trophy list if competing against good pilots with airplanes trimmed so as to mitigate or largely eliminate the deleterious effects of acceleration in the winds and the effects of the accelerated CG on the ability of the airplane to turn corners with the available control deflection. If the CG is forward of the location on the wing where lift is "centered"
(roughly 25% aft of the leading edge at the average chord) any increase of speed in a loop or corner of a given radius will increase the "weight" of the airplane
(g forces). Because that increased weight is forward of where the lift is generated it will attempt to "open up" the corner or make the loop "bigger". (This CG/CL relationship's tendency to "open up" the corner is a form of
"negative pitching moment"). As a result the control deflection required to fly those sized loops or corners will be increased. The pilot will have to substantially modify his/her control inputs compared to what is necessary in good air. It is "entirely" possible that a ship that flew well in good air will not have enough control deflection to over come the "opening up" tendency in high winds and full control will not provide sufficient pitch rotation to avoid the ground. That is not good!
A properly designed and trimmed airplane
(one that has the CG located at or very near that magic 25% of the average chord location AND that has a large enough tail volume to be stable at that CG location) will suffer only a fraction of the "opening up" tendency of the same ship with a more forward CG (slightly off the subject but of interest; there will be some increased input required because simply flying faster [winding up] means that more lift is required to achieve the desired corner or loop size...thus requiring modestly increased flap deflection which is another source of
"negative pitching moment". The amount required is only a fraction of that required by more forward CGs).
The bottom line is: it is of value for a serious upcoming flier to practice enough in high winds to: A. refine his CG trim, and; B become aware of the ultimate effect of high winds on the response rate of the ship; C. Learn how to takeoff and land...which is by far the hardest part of flying a well trimmed airplane in high winds.
Having said that, I'm in complete agreement with Steve with regard to practicing in turbulent conditions. Unlike flying in winds whose effects can be mitigated with proper design and trim because the effects are predictable, turbulence, by definition, is unpredictable and thus can't be mitigated nor can the pilot achieve "knowledge and skills" to prepare for it. If it is hazardous and unpredictable it makes no sense to risk the airplane unless one of those big plastic bowling trophies is at stake!
Ted
Topic: Self Coaching Question.. (Read 4463 times)
