Showing posts with label Vx. Show all posts
Showing posts with label Vx. Show all posts

02 February 2021

Vy Calibration Runs (Sawtooth Climb Performance)


While this is not complete data by any means, this session allowed me to get used to the procedure while at the same time not getting bored just running around in cruise circles. I need to repeat this session with 0 degree flaps as soon as I get the wheel pants on. Also, yes, I do have an EFIS that is recording at 1Hz and the abbreviated method of this calculation would be faster. That said, I am in Phase I and I am taking into account that it benefits me to learn the plane while still close to the airport, so longer procedures are not an issue. Calculations were based on this method. OAT was 6C at altitude and the airplane starting conditions had me weighing in at 2230lbs.

I ended up doing x8 valid 60 second climbs dropping the indicated air speed 5 knots per run. I started with 120 KIAS and ended at 85 KIAS. I still need to take this down to 75 but I want to run the power on stall tests before going lower. The figure below shows the 8 runs (the first one I am removing from the data set because I forgot to set a timer). The top sawtooth graph is Autopilot IAS versus Indicated Altitude. The bottom graph is KIAS versus Vertical Speed. A reminder on Vx and Vy. Vx is the slowest (IAS), and is the Maximum ANGLE of climb.  It allows one to climb to altitude within the shortest horizontal distance. Vy is slightly faster, and is the Maximum RATE of climb. It allows one to climb to altitude in the shortest time.



<todo: get the excel diagram output here>


Below are the calculated angles as defined by Google Earth Pro: