A queston about the attitude indicator.

[domini99]

I remember someone saying that if you´d put a plane in an aileron roll you could ruin the attitude indicator, i know that aerobat Cessna 152 has a caging button for that, how is this in the Cessna 172r? FSX probably doesn't simulate it. Which kind of attitude indicator can get ruined by a roll, can the 172r's one get ruined by an aileron roll?

Not that i'm ever going to do an aileron roll in a 172, but i'm still wondering


~Dominique

[Tug002]

Hey there domini99, have you tried putting the pointer over the knob and using the mouse wheel?

Keep smiling
Tug

[EnDSchultz]

If I recall, it was said that the vacuum system, for the time being, is still simulated using stock FSX, so I assume that includes the behavior of the attitude indicator.

[Oracle427]

The attitude indicator has limits in the gimbals that prevent it from freely rotating beyond certain angles. As a result of this the gyro will begin to tumble as it tries to maintain stability in space.

By forcing the gyro to the stops, you are putting a lot of stress on the bearings and the joints in the gimbals that will ultimately decrease the life of the component.

[Tug002]

Hey there domini99, have you tried putting the pointer over the knob and using the mouse wheel?

Keep smiling
Tug

Oops, I dont know how but I put this in the wrong post Sorry

Keep smiling
Tug

[AKar]

By the way, does anyone happen to know the gimbal limits, if there are any, of standard equipment attitude indicator in Cessna 172R/S? By quickly looking, I didn't find any mention about it either in the Information Manual nor in the AMM.


-Esa

[DHenriques_]

By the way, does anyone happen to know the gimbal limits, if there are any, of standard equipment attitude indicator in Cessna 172R/S? By quickly looking, I didn't find any mention about it either in the Information Manual nor in the AMM.


-Esa

Memory is sketchy but 60 degrees seems to ring a bell.

[domini99]

It's not like I'm going to flip a 172 upside down in real life, like one has in his signature, "keep the shiny side up and the dirty side down" (or atleast something like that ) but I was curious, because in fsx the indicator is indistructable

Thanks for the info

[AKar]

Domini,

I don't think that the instrument would be immediately broken if the gimbal limits were hit at the rate the airplane moves around, though repeatedly doing so could very well harm the instrument. It's more that the attitude information goes unreliable as the gyro would loose its orientation and would need to be reset at straight and level flight.

-Esa

[Oracle427]

AKar,

I don't believe it is the rate of the aircraft rotation that matters as much as the force applied to the bearings by the gyro it reaches the stops. It will precess and tumble causing it to repeatedly bump against the stops. I have observed this behavior and it lasts a few minutes. I don't know how well bearings wear when exposed to bending loads, but I imagine it isn't good for them!

[AKar]

I don't believe it is the rate of the aircraft rotation that matters as much as the force applied to the bearings by the gyro it reaches the stops.

I'd say the two are rather connected to each other in this case. Point being, if you subject an attitude indicator to rates that manual handling in a test bench for example could mean, I wouldn't be surprised if the gimbals/bearings sustained immediate damage when hitting the limits. I would guess that the instruments are designed an occasional limit reaching in mind at rates they could be subjected when installed in an aircraft (so that they are not destroyed by it), but could be wrong.

I have observed this behavior and it lasts a few minutes. I don't know how well bearings wear when exposed to bending loads, but I imagine it isn't good for them!

Yeah, I believe it does that until the gravity-based averaging and the dampening gradually slow the gyro's bouncing and pulls it back in to its operating limits. Surely it looks painful to it at least! Not surprised if it can seriously reduce the time to next overhaul...

-Esa