Talk:Attitude indicator

Standard rate turn

• 260 degrees in 2 min, bank angle depends on airspeed and has to be calculated => is not 15 degrees bank —Preceding unsigned comment added by 85.127.188.9 (talk) 09:31, 22 July 2009 (UTC)

True - I've updated the article. In the future though be bold. Johnnie Rico (talk) 03:03, 29 August 2009 (UTC)

Did the original poster mean to say 360 degrees? Captain Quirk (talk) 21:33, 21 June 2017 (UTC)

Yes, the correct figure is 360 degrees. A useful mnemonic is to say the rate of turn is equal to the number of direction reversals (180 deg) per minute.

There is nothing significant about 260 degrees. Dolphin (t) 00:08, 22 June 2017 (UTC)

Pitch vs. level flight

"If the horizontal lines and the dot are above the horizon line, the aircraft is gaining altitude and is pitched upward."

just because the nose is pointing upward it does not mean you are gaining altitude, you also need enough airspeed am i right? (flight simulator user :) )

I'm not a pilot, but I believe you're right. Usually, the nose must be pitched slightly upward to maintain level flight, at least in an airplane. It might have to be slightly down, however, in a helicopter. Those who know better should provide some input, either here or at the appropriate spot in the article. 76.21.8.213 (talk)

Most aircraft require a nose up pitch attitude of 1 to 2 degrees to maintain a level flight path and normal cruise speed. If you increase either the pitch or the speed (or both) then the aircraft will climb. (I am a pilot btw) 92.24.141.28 (talk) 16:34, 10 May 2009 (UTC)

History of the artificial horizon goes back 265 years

"In 1742 or 1743, the Englishman John Serson presented a fast spinning top, whose upper surface perpendicular to the axis of its rotation was a circular plate of polished metal.

When the top was set in motion, the plain part of its surface became horizontal while maintaining this behaviour even in a disturbing environment like on swaying ships. With this, J. Serson proposed a solution of the problem of finding a satisfactory horizon for use in sextant observations at sea when there was fog around the sea horizon. Herefrom the artificial horizon originates.

Unfortunately, J. Serson lost his life in 1744 during a test campaign at sea. It took about 140 years before his invention was revived in France by Admiral G. Fleuriais."

This is from Wagner, "200 Years of Inertial Navigation"

Perhaps the article could be expanded to include the historical development of the subject. --TraceyR (talk) 09:06, 15 December 2008 (UTC)

There is a good essay by Simon Schaffer about the history of the artificial horizon here - http://cudl.lib.cam.ac.uk/view/ES-LON-00001 with links to original manuscripts on the subject in relation to solving the problem of Longitude Irisbox (talk) 14:15, 23 July 2013 (UTC)

The history is needed. This is essay covers some of the U.S. history: McIntosh, Maj. David M. (April 1988). The evolution of instrument flying in the U.S. Army (PDF)

link Johnvr4 (talk) 15:07, 12 November 2022 (UTC)

Feel free to add that from the ref you cited! - Ahunt (talk) 15:45, 12 November 2022 (UTC)

pitch, bank, and roll

Pitch and bank are ANGLES. Roll is a RATE (degrees/time). The AI shows pitch and bank only, not roll.

Roll rate can be implied by the pilot by watching how fast the bank angle changes, but the roll rate is not directly shown on the AI.

The (older) turn indicator shows turn rate only. The modern turn coordinator shows turn rate + roll rate. As you enter a turn, the plane has a high roll rate and low turn rate. When the turn is established (and held with constant bank angle) roll rate is zero and the indicator shows turn rate + (zero) roll rate.

Note that if the aircraft is rolling about the longitudinal axis and not turning, the turn indicator will read zero, while the turn coordinator will register the changing roll rate.

A standard rate turn is 360 degrees in 2 minutes (for slower aircraft). The turn coordinator (or turn indicator) has index marks for a standard rate turn. A quick formula for bank angle to effect a standard rate turn is:

15% of airspeed (in knots) = bank angle.

For 90 Kt. bank angle = about 13.5 deg. For 120 Kt. vabk angle = 18 deg.

The AI is used to set bank to a specific angle, then the turn coordinator is used to monitor the quality of the turn via roll rate. — Preceding unsigned comment added by 69.239.146.121 (talk) 19:07, 2 June 2013 (UTC)

I agree, it indicates bank, not roll. I've removed it. Burninthruthesky (talk) 21:09, 23 July 2014 (UTC)

Archive link for reference

Reference 3 is not available anymore, but there is an archive link: http://web.archive.org/web/20141029214654/http://www.flightglobal.com/blogs/learmount/2009/02/which_way_is_up_for_eastern_an/

Can someone who knows more about the syntax than me please replace it? --MrBurns (talk) 01:10, 15 September 2015 (UTC)

 Done. Thanks for the suggestion. Have a look at my change to see how I did it. Burninthruthesky (talk) 06:49, 15 September 2015 (UTC)

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Burninthruthesky (talk) 12:46, 6 April 2016 (UTC)

Criticism of presentation of Russian attitude indicator

The following editorial comments were inserted in the article - see the diff. I have removed the following comments from the article: Dolphin (t) 11:19, 26 November 2019 (UTC)

191126 CAUTION: This graphic is inaccurately presented. A further discussion & correction will be offered when time permits.

This editor is a retired airline pilot and flying instructor. The graphic on this page of the 'soviet' or Russian artificial Horizon (AH) is incorrectly orientated, very wrong in presentation, and therefore confusing and misleading.

I do not have the skills to correct the graphic in this page, but could do it on my Mac, but how would I return it to this page?

Basically, the central dark slot which may be observed in the centre of the instrument's glass, is a shielded slot through which the aircraft symbol is raised or lowered on a lever controlled by a gyroscope or other device, to indicate pitch attitude variations of the aircraft.

Both the graphic here, and the instrument in the cockpit must be mounted such that the vertical axis of the page, and of the slot in the instrument in the cockpit are all aligned with the vertical. i.e. the slot is rigid & fixed.

The aircraft symbol is raised & lowered to reflect pitch, and rotated clockwise viewed by the observer (to indicate a right bank) or anticlockwise (to indicated a left bank,) both motions being driven simultaneously as required.

Put another way, if you are a pilot strapped to your seat and looking at the AH, that central instrument slot will be aligned with your backbone. Always.

See the discussion at https://aviation.stackexchange.com/questions/51791/how-is-a-confusion-possible-between-western-and-russian-attitude-indicators where initially the web-site builder made the same graphic presentation error. That error is called out further into the article, but the wrongly orientated graphic remains.

The graphics all appear to photographs of a WW2 vintage salvaged instrument, and not representative of modern Russian instruments, as all the 'Western' graphics depict.

See also: https://commons.wikimedia.org/wiki/File:Soviet_artificial_horizon_AGP-2_-_front_panel.JPG

Also see: https://commons.wikimedia.org/wiki/File:Soviet_artificial_horizon_AGP-2_-_whole_view.JPG

If the link to the YouTube video is retained, as I guess it would be, I would add a note to be very cautious regarding what is presented in the video - it verges on confusion and hysterical production values.

Noted added by JenSee 191126 aka 26 Nov 2019 aka Nov, 26, 2019. Apologies for unprofessional presentation, TLTTOL (Too Late Too Tired Old Lady)

Perhaps it would be better to just remove the photo? - Ahunt (talk) 12:10, 26 November 2019 (UTC)

Best would be to have a better, modern photograph. However, we don't, so I have used an image of the same instrument, but this time showing its body, so the tilt is seen, and changed the description to be more useful. Completely removing it would make it even more difficult to describe this system. (Hohum ^@) 20:02, 26 November 2019 (UTC)

The photo is still incorrect: it needs to be rotated so that the center slot is vertical, to show the attitude indicator from a pilot's perspective. That slot should be, as stated above, "aligned with the pilot's backbone. Always." Also, the (corrected) photo should be moved into the article section that contains the text describing it. 107.77.192.178 (talk) 04:32, 9 February 2020 (UTC)

That would be more confusing, not less. The image shows that the instrument is tilted, and the effect on the instrument. (Hohum ^@) 15:24, 9 February 2020 (UTC)

But it is unlike the other images in this article... they all show the instrument upright (as a pilot would see it). The examples in the aircraft_orientation image show the normal/usual portrayal of an artificial horizon. The AGP-2 image needs to be consistent to show how the old-style attitude indicator (what this article calls "Russian", maybe the Russians still use it) is different. 107.77.192.209 (talk) 02:52, 10 February 2020 (UTC)

The caption clearly explains the difference in presentation. We only have limited images of the Russian type of indicator available. (Hohum ^@) 17:09, 10 February 2020 (UTC)

Understood. And yes, I agree the current image and its caption are an improvement. Thank you. 166.216.159.112 (talk) 01:52, 11 February 2020 (UTC)

Curvature of Earth

So an Attitude Indicator does NOT work by measuring the direction of gravitational pull? I thought it was a free-floating ball with the bottom full of something heavy. Wouldn't a gyroscope become inaccurate due to the curvature of the Earth? Algr (talk) 01:09, 19 October 2021 (UTC)

It is all explained in detail at Attitude indicator#Operation. - Ahunt (talk) 01:11, 19 October 2021 (UTC)