I've seen several posts lately with comments regarding the use of the shield, or rather the lack of the shield in conjunction with the IMU. It would seem most of the Beta testers are not using the shield. I have aslo read comments that the shield is not necessary when the IMU is used.
If this is true how is airspeed controlled?
I am using an Ardupilot with ArduIMU+ v2, I also have a shield v2,and ublox5 gps. I will be using this setup in a "slow" (about 15 meters/sec cruise) flying high wing airframe. Can you controll airspeed without the use of the shield? If so what differences can one expect.
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If you do not have the shield there is no airspeed measurement, and there is no speed control. You pick a cruising throttle setting to give an appropriate airspeed in straight and level flight. Throttle is increased or decreased to climb/descend in proportion to the commanded pitch.
If you do have the shield then you have airspeed control. Pitch control maintains airspeed and throttle control is used to climb/descend.
Read the code in the attitude.pde file to see how all this works.
Do you need the shield - for many cases the answer is no. You really only need it if airspeed control is important. Airspeed control is important if you are trying to fly close to stall speed, or if you are trying auto landings.
About the only way to control the airspeed without a Shield is either manually or with the GPS. The GPS velocity resolution, I believe, is not that accurate, but neither is the differential pressure sensor on the Shield according to some members.
Chris has said that his plane flys so fast that he does not bother with the differential pressure sensor and I assume uses manual control of the throttle.
Regards,
TCIII