# What would happen if I flew through a city at Mach 3? **URL:** \ **Category:** Factual Questions\ **Created:** [July 15, 2025, 11:07pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896 "2025-07-15T23:07:03Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [July 16, 2025, 4:09pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/21 "2025-07-16T16:09:56Z")
What I am saying is that obstacles, both moving and not moving, make it impossible to travel in a straight line at mach 3. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [July 16, 2025, 4:15pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/22 "2025-07-16T16:15:58Z")
Is there any way to find out how fast the jet was going? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 16, 2025, 4:16pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/23 "2025-07-16T16:16:11Z")
Short version is you don’t make sharp turns at Mach 3. Longer version is the relevant equation is centripetal acceleration = speed^2 / turn radius. Which in English says that when you are going stupid fast, you either pull insane Gs turning or have a ginormous turn radius. Those two factors trade off directly. In American units, Mach 3 is roughly 3400 ft/second. Square that and you get ~11.5million ft^2/s^2. If you want a WAG 30 foot turn radius to stay over the curbside lane making a 90 degree turn on a street grid, you’re looking at a centripetal acceleration of 11.5M/30 or about 380,000 ft/s/s acceleration. Since normal familiar gravity is one G is 32 ft/sec/sec you’re looking at about 12,000G to make that turn. So more or less the same amount of violence as a modern artillery shell experiences while being fired out of a modern cannon. Any human subjected to that would simply be converted into a thin red mist slowly dispersing in the breeze. Superman? Who knows? ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [July 16, 2025, 4:17pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/24 "2025-07-16T16:17:49Z")
And a ginormous turn radius just isn’t possible in any city. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 16, 2025, 4:25pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/25 "2025-07-16T16:25:56Z")
> [@LSLGuy](#): > > Which in English says that when you are going stupid fast, you either pull insane Gs turning This is Superman we’re talking about here, right? I think he can take the g-forces. As far as violating FAA rules, someone else will have to tell he’s doing that. Not my job to enforce those.† † This statement applies to almost everyone, especially everyone he meets in the comics. ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [July 16, 2025, 4:29pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/26 "2025-07-16T16:29:25Z")
You don’t tug on Superman’s cape nor try to enforce FAA regulations on him either. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [July 16, 2025, 4:33pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/27 "2025-07-16T16:33:37Z")
But is there a secondary effect from having a sonic boom from one angle smash into a sonic boom from another angle? ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [July 16, 2025, 4:38pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/28 "2025-07-16T16:38:11Z")
> [@Czarcasm](#): > > Can you imagine the amount of mach 3 swerving that would have to be done? > BTW, what _does_ happen when you have to make a very sharp turn at that speed? G-forces I expect. Of course, any turn imposes some g-force. Usually not enough to notice with most forms of transportation. Probably more usual with airplanes. A lot depends on turning radius. Also angle of bank. I’m _guessing_ that is you’re enough like Superman to fly at Mach 3 like that you have the require secondary powers to deal with any g-forces you may experiences while dodging obstacles. Also, what @LSLGuy said. ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [July 16, 2025, 4:54pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896/29 "2025-07-16T16:54:29Z")
I checked on their own website, and as near as I can tell they flew just fast enough to create a sonic boom, so I would have to assume (until shown otherwise) that they got nowhere near Mach 3. [MythBusters Episode 123: Curving Bullets](https://mythresults.com/curving-bullets) [Previous page](https://boards.straightdope.com/t/what-would-happen-if-i-flew-through-a-city-at-mach-3/1020896.md?page=1)