Attitude Indicator Help

[Will273 23]

Some general aviation aircraft have attitude indicators or artificial horizons that are adjustable where you can move the little icon that represents the airplane up or down. In Carenado's Seneca ii the little icon is fixed to where it can't be adjusted...it might be called a sky pointer. I've seen these in other aircraft too. Sitting on the ground it has close to a 5 degree pitch up attitude so I'm wondering how this works. How does this relate to straight and level flight and can it be adjusted? 

[skelsey 765]

Silly question, but is the engine running? The artificial horizon, like the turn coordinator and direction indicator, relies on spinning gyroscopes. These are (typically) powered using air jets - air is ducked from the instrument casing by an engine-driven vacuum pump and replacement air flows in through the jets and spins the gyro. No vacuum pump (ie engine off) means the gyros will topple and give strange readings.

[Will273 23]

Yes...engine is running and showing a 5 degree pitch up. Not sure how these type work but will take it up again and have a closer look...might need to be in the air before it becomes functional...just wondering.

[skelsey 765]

Just had a look at a video showing the Carenado Seneca; it looks to me as though the aircraft on the ground sits at a slight nose-up attitude, so that would explain it. It does not look adjustable.

Regarding your question as to how it relates to straight and level flight, obviously the pitch attitude required for straight and level will depend entirely on the airspeed so it's difficult to relate the attitude the aeroplane sits in on the ground to the attitude required for straight and level...

[Will273 23]

Yea...just did a test flight and it straightened out once I got in the air. As you said...level flight depends on a lot of things but I was expecting this attitude indicator to be like the others and it's not...this one seems sort of self adjustable so has no adjustment knob...something along those lines. Anyway once I got in the air and leveled off the pointer came to a rest right on the horizon. It will vary depending on speed, weight, etc. Thanks for taking the time to help skelsey.

[n4gix 4,947]

A few modelers don't even make the effort to animate the 'flying wings' so they may be adjusted. The purpose of the manual adjustment is so that once level flight is achieved, the pilot can adjust the 'flying wings' to reflect level flight. As stated, level flight can occur at different angles of attack depending on airspeed, among other factors.