# ­xkcd thread **URL:** \ **Category:** Cafe Society\ **Tags:** comic-strips\ **Created:** [May 28, 2020, 12:57am UTC](https://boards.straightdope.com/t/xkcd-thread/854574 "2020-05-28T00:57:03Z")\ **Posts on this page:** 20\ **Page:** 240
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [August 5, 2025, 11:18pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4783 "2025-08-05T23:18:25Z")
Juts turn the autopilot on while on the ground. That’ll keep you from taking off. ---
**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:** [August 6, 2025, 12:43pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4784 "2025-08-06T12:43:42Z")
> [@Pleonast](#): > > That’s the usual mode of operation, but do airplanes have configurations that reduce lift (or even negative lift)? The spoilers laid out across the top of the wing do a pretty good job of killing the lift. Not all the way to zero AFAIK, but pretty close. They also greatly increase drag and would, ignoring tire failure issues, reduce the maximum taxi speed at least some. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [August 6, 2025, 6:36pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4785 "2025-08-06T18:36:23Z")
> [@LSLGuy](#): > > They also greatly increase drag and would, ignoring tire failure issues, reduce the maximum taxi speed at least some. Yes. Those sort of confounding factors is why “land speed record of flight-worthy vehicle” might be interesting. ---
**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:** [August 6, 2025, 8:12pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4786 "2025-08-06T20:12:58Z")
Assuming box-stock airliners, the problem is that at about 200ish mph the tires will start shredding. Even at a sustained speed of 150ish mph they’re going to overheat in a a handful of minutes and start shredding then. So, much like the genuine land speed record cars up near Mach 1.0, how you handle the running gear pretty well determines the max speed. We can always add more thrust to go faster. No reason in principle you could not add wings and a flight control system to one of the record setting cars and get something that could fly after a fashion and also taxi after a fashion up around Mach 1. Just bring money. And a willingness to have some very high speed accidents at ground level during development. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 6, 2025, 8:17pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4787 "2025-08-06T20:17:12Z")
> [@LSLGuy](#): > > No reason in principle you could not add wings and a flight control system to one of the record setting cars and get something that could fly after a fashion and also taxi after a fashion up around Mach 1. Just bring money. Sounds sort of like the project to build an upside-down racecar. ---
**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:** [August 6, 2025, 8:48pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4788 "2025-08-06T20:48:14Z")
Yeah. Equally wacky. Although I think if I had to build the flying car record setter machine I’d start with a fighter, say F-15, and bolt on the wheels and tires and steering arrangements from a land speed record car. it’ll still go plenty fast even with that extra drag ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [August 6, 2025, 9:05pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4789 "2025-08-06T21:05:42Z")
Naw, rocket car all the way. The _Blue Flame_ set records (630 mph) 50 years ago with a fairly primitive peroxide-LNG rocket that was deliberately restricted in performance. Stick in a LOX-LNG staged combustion engine and you really have unlimited thrust. The real issue is stability. Ideally you want to be essentially flying low to the ground. I think the cars are basically at the limit of passive stability–there just isn’t enough margin to keep the car stably on the ground at those speeds. You really want active stability, probably with both active aerosurfaces and with reaction control thrusters. None of which would be human controlled, as with rockets. The issue is that this would cost about that of a small orbital-class rocket to develop. So, $100M or so. I don’t think there’s enough money in the sponsorship industry for that. ---
**Author:** ![Pardel-Lux](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pardel-lux/32/20182_2.png) [@Pardel-Lux](https://boards.straightdope.com/u/Pardel-Lux)\ **Post date:** [August 6, 2025, 9:10pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4790 "2025-08-06T21:10:43Z")
Formula 1 cars have more downdrift than their weight at a certain speed, so they could run on the ceiling of a tunnel. Don’t know if that counts as flying, and they are not designed to carry passengers, but they sure are fast. Now find a tunnel to your destination and make sure you have enough petrol (pit stops will be hard) and that it flows towards the engine despite the car being upside down. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 6, 2025, 9:32pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4791 "2025-08-06T21:32:44Z")
> [@Pardel-Lux](#): > > Formula 1 cars have more downdrift than their weight at a certain speed, so they could run on the ceiling of a tunnel. That’s what I was referencing. There’s a lot more to it than that, and a wide variety of technical challenges, but there is a team that’s working to build a car that can do just that. I’m not sure how close they are, or if they’ve even maybe already done it by now. ---
**Author:** ![TroutMan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/troutman/32/6721_2.png) [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Post date:** [August 6, 2025, 9:59pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4792 "2025-08-06T21:59:42Z")
> [@LSLGuy](#): > > Assuming box-stock airliners, the problem is that at about 200ish mph the tires will start shredding. Even at a sustained speed of 150ish mph they’re going to overheat in a a handful of minutes and start shredding then. What if you position the flaps so you’re getting some lift, but not enough to get off the ground. Make the effective weight of the plane just a few pounds, and your tires should last a bit longer. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 6, 2025, 10:00pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4793 "2025-08-06T22:00:44Z")
The record for a _wheel-driven_ land vehicle is 482 mph. Faster than that and you basically have an airplane that’s skimming along the ground. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [August 6, 2025, 10:37pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4794 "2025-08-06T22:37:40Z")
I wonder if the requirements specify wheels. Or wheels that turn. At a certain point, you’re probably better off with skids. I assume it has to touch the ground in some fashion, but what are the limits? ---
**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:** [August 6, 2025, 11:53pm UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4795 "2025-08-06T23:53:50Z")
The sky is the limit! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [August 7, 2025, 12:58am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4796 "2025-08-07T00:58:28Z")
> **[Snake-in-the-Box Problem](https://xkcd.com/3125/)** [![](https://imgs.xkcd.com/comics/snake_in_the_box_problem.png) ](https://imgs.xkcd.com/comics/snake_in_the_box_problem.png) “Chemistry grad students have been spotted trying to lure campus squirrels into laundry hampers in the hope that it sparks inspiration.” ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [August 7, 2025, 1:05am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4797 "2025-08-07T01:05:09Z")
Online Encyclopedia of Integer Sequences number A099155 ([A099155 - OEIS](https://oeis.org/A099155)) ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [August 7, 2025, 1:09am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4798 "2025-08-07T01:09:00Z")
Psychologists have been putting cute animals in boxes for ages. Oh sure, they call it an “operant conditioning chamber” or something in public, but when you aren’t around it’s just a Skinner box. And they don’t mess around with _thought_ experiments. ---
**Author:** ![abcdefghij](https://avatars.discourse-cdn.com/v4/letter/a/43a26b/32.png) [@abcdefghij](https://boards.straightdope.com/u/abcdefghij)\ **Post date:** [August 7, 2025, 1:25am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4799 "2025-08-07T01:25:22Z")
There’s the box that accompanies the Gom Jabbar. I’m not sure that Bene Gesserit witch counts as a scientific discipline. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 7, 2025, 2:12am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4800 "2025-08-07T02:12:48Z")
> [@Dr.Strangelove](#): > > I wonder if the requirements specify wheels. Or wheels that turn. At a certain point, you’re probably better off with skids. I assume it has to touch the ground in some fashion, but what are the limits? As I recall, the X-15 rocket plane and the proposed X-20 Dyna-Soar used “wire brush” landing skids instead of wheels because their crappy glide ratios translated into extremely high landing speeds. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [August 7, 2025, 2:40am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4801 "2025-08-07T02:40:23Z")
Yeah, as does the Dream Chaser for the front gear: [![](https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/Dream_Chaser_pre-drop_tests.5.jpg/1920px-Dream_Chaser_pre-drop_tests.5.jpg) ](https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/Dream_Chaser_pre-drop_tests.5.jpg/1920px-Dream_Chaser_pre-drop_tests.5.jpg) Works fine as long as steering isn’t a high priority. Just use thrust vectoring. ---
**Author:** ![Ponderoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ponderoid/32/19221_2.png) [@Ponderoid](https://boards.straightdope.com/u/Ponderoid)\ **Post date:** [August 7, 2025, 4:38am UTC](https://boards.straightdope.com/t/xkcd-thread/854574/4802 "2025-08-07T04:38:32Z")
Thanks for saving me the effort. [Previous page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=239) [Next page](https://boards.straightdope.com/t/xkcd-thread/854574.md?page=241)