To avoid injury to passengers (too many G's) was there a max 'sharpness' of the turns it made when travelling at certain speeds?
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11$\begingroup$ It didn't make turns of any significance when flying supersonic (no commercial aircraft makes significant turns in cruise). When it was making significant turns when departing and arriving, it was flying at the same kind of speeds as any other aircraft. In any case, when turning at a given bank angle, the speed has no impact on the G force felt. Rather, the turn radius increases. $\endgroup$– SimonCommented Sep 30, 2016 at 19:47
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8$\begingroup$ Crew flying passenger transport aircraft—whether super or sub-sonic— generally limit the aircraft bank angle to 30° or less. A level turn at a given bank angle will result in a specific corresponding load factor—or G-loading—regardless of speed. A level turn at 30° of bank at any speed will yield a load factor of only about 1.2 (1.2 Gs, as opposed to the normal 1.0 Gs). This is fairly imperceptible. $\endgroup$– J WCommented Sep 30, 2016 at 19:52
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2$\begingroup$ @ymb1 SR-71 was not a passenger aircraft ;-) $\endgroup$– KorvinStarmastCommented Sep 30, 2016 at 20:46
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6$\begingroup$ Most airliners will disintegrate before an injury caused by a sustained G can be inflicted. (Most people will easily bear 3G, while most airliners won't (though won't necessarily disintegrate yet)). Injuries may happen because of a sudden force, but this doesn't normally happen when entering a turn. $\endgroup$– ZeusCommented Oct 3, 2016 at 3:22
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2$\begingroup$ I once read that the sr71 took most of North Dakota to turn around at cruise. Mach 3, military pilots. Bank angle? $\endgroup$– DonCommented Dec 8, 2017 at 8:10
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2 Answers
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All aircraft experience the same G force per degree of bank angle, so a 60 degree turn in a Cessna produces 2G just like a 60 degree turn in Concorde would produce 2G.
The difference is that a Cessna doing 100 knots could circle in 0.2 miles by using a 60 degree bank angle.
Concorde doing 1000 knots and 60 degrees would take up 19.5 miles to do the same thing.
In both cases the passengers would experience 2G which even so is pretty severe if you are a passenger and aren't used to it. It would get your attention let me put it that way.
I'm not an airline pilot. However I would think that the risk with higher speeds is in angle of attack or angle of attack combined with bank angles. At higher speeds its much easier to produce a whole load of G by pulling or pushing the controls than it is in your Cessna, and even that can be pretty severe.
So while you might not worry as much about bank angles you would be very careful not to pitch up or down too far especially at higher speeds because you could overstress the aircraft real easy.
Hopefully a pilot who knows Concorde and / or airliner systems can improve on this answer.
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The math to verify Mr. Philip Johnson is given below. The maximum bank angle for a normal category aircraft is 60deg at 2G's. The formula for turn radius is
$R = \frac{V^2}{G\cdot tan(bank)}$
given
$V = 168900(ft/sec) = 1000kt \cdot 1.68$
$G = 32.2(ft/sec)$
$tan(bank) = 1.7(60deg) $
$R = (1690^2) / (32.2 * 1.7) = 52175(ft) = 9.8mi$
$19.76.4mi$ diameter = $9.8(radius) \cdot 2$
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$\begingroup$ Well, the maximum operational bank angle of airliners is nearer 30°. Pulling more than 1.15gs is frowned upon among airline pilots. $\endgroup$ Commented Dec 9, 2017 at 8:26
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1$\begingroup$ I couldn't agree more. I used the 60 degrees of bank in my example because I wanted to show that large angles of bank on its own shouldn't cause too many problems even at high speed, but pitching most definitely will. Also everything gets so sensitive at higher altitudes and speeds and the aircraft needs finer control. Is that because you are deeper into coffin corner where Vne meets stall speeds? Sorry maybe I should ask a question.. $\endgroup$ Commented Dec 10, 2017 at 21:20
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2$\begingroup$ I am a pilot and A&P. 30 degrees is not a regulation, it is a recommendation by the FAA for passenger comfort on commercial operations and a safety consideration for IFR flights (the higher the bank angle, the higher stall speed and harder controlability). 60deg is the legal maximum an aircraft is allowed to be banked unless certified for aerobatic maneuvers. 60deg of bank is the required for certification under the "normal" category of all aircraft - they must have a structural load limit of 4.7g which gives a safety factor of 2x or about ~2g more than would be encountered in legal maneuvers. $\endgroup$ Commented Dec 11, 2017 at 8:36