ORIGINAL: HarryC
ORIGINAL: ravill
I can see your point. That said, MANY people are doing just what I am planning with two gyros aligned at 45 degrees.
Yes with
two gyros aligned at right angles to each other, for example one aligned 45 degrees inwards and the other 45 degrees outwards. But you can't do it with one gyro which rules out using one dual input/output gyro like the ACT Fuzzy Pro. You could use two Fuzzy Pros and just use one input/output of each but that gets a very expensive way of doing it.
There is still a potential disadvantage to using a gyro aligned at 45 degrees to the two axes you want to involve. There is only one gain setting so it will respond with the same amount of control travel to pitch and roll. Depending on the model, this may be very unequal. For example, on my Typhoon elevons, the elevator travel is large and the aileron travel is small. Therefore the roll gain is very low. If I aligned the gyro at 45 degrees then the gain would have to be a bit higher but the end result is the same, a small amount of control deflection. It would respond the same way to pitch disturbance, a very small deflection of elevator which would have no useful effect since the elevators need a lot of travel. Turning the gain up to an amount useful to elevators would be several times too high for the ailerons and a severe rolling wobble sets in as soon as the gain exceeds a critical point. So the only option is to set the gain for roll, which would be too low to be of any use in pitch, thus negating all the bother of setting it up that way. It will depend on the travels for your particular model.
By far the best option would be two gyros but one on each separate axis so you can set different roll and pitch gains. That would require them to be fitted in series in order to drive elevons, don't know if that would cause any problems.
H
In this instance you could increase the mounting angle, say to 110 degrees, which would increase the visability of the roll rate at the gyro while decreasing the pitch. It would take some expermenting, but could be done.
For what its worth - the gyros in an Inertial Measurement Unit (IMU) are at 45 degrees to the major axis'. Of course there are 3 gyros and a computer to come up with the final answer. An IMU is the device in a missile, airplane, or sub that tells it how it is moving.
Steven