# Maximum size for a heavier-than air plane? **URL:** \ **Category:** Factual Questions\ **Created:** [April 27, 2009, 6:19pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530 "2009-04-27T18:19:34Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [April 27, 2009, 6:19pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/1 "2009-04-27T18:19:34Z")
I _think_ I remember reading that there is a maximum size possible for an airplane, due to air density or something. I don’t know. Maybe I read it while reading about dirigibles. What made me think of this? This [bemouth](http://tailspinstales.blogspot.com/2009/02/huge-kalinin-k-7-bomber.html), which I came accross this morning. Peace, mangeorge ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [April 27, 2009, 6:45pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/2 "2009-04-27T18:45:12Z")
So far as I know, the limitation comes from the strength of materials used to build it. If a material existed that was strong enough to build a 2000’ wing with, someone would probably have done it already. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [April 27, 2009, 6:52pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/3 "2009-04-27T18:52:57Z")
> [@UncleRojelio](#): > > If a material existed that was strong enough to build a 2000’ wing with, someone would probably have done it already. If you’re talking about practical as opposed to theoretical limitations, many factors besides material strength come into play. Included would be such things as cost and suitable takeoff/landing locations. Both of these strongly argue against 2000’ wingspans, regardless of other considerations. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [April 27, 2009, 7:01pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/4 "2009-04-27T19:01:10Z")
> [@Xema](#): > > If you’re talking about practical as opposed to theoretical limitations, many factors besides material strength come into play. Included would be such things as cost and suitable takeoff/landing locations. Both of these strongly argue against 2000’ wingspans, regardless of other considerations. The OP didn’t mention practicality. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [April 27, 2009, 7:19pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/5 "2009-04-27T19:19:58Z")
The [Boeing 747 Dreamlifter](http://www.boeing.com/commercial/787family/dreamlifter_fact.html) has a maximum takeoff weight of 803,000 pounds. The Russians [have a bigger plane](http://www.aerospaceweb.org/question/design/q0188.shtml). The Airbus A380 might top out at 1.23 million pounds. Of course, that means the Splat! factor will be just that much bigger when it crashes fully loaded commercially for the first time. ---
**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:** [April 27, 2009, 7:20pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/6 "2009-04-27T19:20:10Z")
It doesn’t seem to me that there should be any absolute limit, even granting things like finite material strength. If you think about it, there’s no reason in principle you couldn’t take a hundred normal-sized airplanes side-by-side, and connect all their wingtips together. You’d be hard-pressed to keep everything functioning at once, and you’d need very good control systems to keep internal stresses down, and wind shear would be problematic, and above all there’d be no practical application for such a behemoth, but there’s no reason it couldn’t be done. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [April 27, 2009, 7:20pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/7 "2009-04-27T19:20:27Z")
> [@UncleRojelio](#): > > The OP didn’t mention practicality. Right - you alluded to it by saying that if it were possible, someone would have probably done it. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [April 27, 2009, 7:28pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/8 "2009-04-27T19:28:09Z")
> [@Chronos](#): > > It doesn’t seem to me that there should be any absolute limit, even granting things like finite material strength. If you think about it, there’s no reason in principle you couldn’t take a hundred normal-sized airplanes side-by-side, and connect all their wingtips together. I think this is a good analogy, and there would be at least one meaningful benefit from doing so: the wingtip vortices would be seriously reduced, yielding improved efficiency. No doubt the problems of maneuvering would be substantial. ---
**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:** [April 27, 2009, 7:33pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/9 "2009-04-27T19:33:44Z")
The thing the OP linked to is a Photoshop hoax. There was a real Kalinin K-7 prototype, but somebody has created a bunch of fake pictures which scaled that airplane up from ~737 size to something a thousand feet wide, then added a couple dozen engines & little tiny people. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [April 27, 2009, 7:40pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/10 "2009-04-27T19:40:53Z")
The limit is hard to define unless you’re talking about a specific shape and materials and construction method. The square-cube effect is present in scaling, and that gets harder to deal with at larger sizes. The wing’s area, and lift capability, goes with the square of the linear dimension, but the airplane’s volume (and, roughly, weight) goes with the _cube_. Wing loading (weight divided by area) gets higher, and therefore angle of attack required for level flight goes up until at some point it will stall instead. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [April 27, 2009, 7:42pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/11 "2009-04-27T19:42:16Z")
Btw, for a lighter-than-air craft, the square-cube law imposes a \*minimum \*size. Similar logic except that the problem is gasbag buoyancy, not wing loading. ---
**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:** [April 27, 2009, 7:52pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/12 "2009-04-27T19:52:33Z")
> [@](#): > > The square-cube effect is present in scaling, and that gets harder to deal with at larger sizes. The wing’s area, and lift capability, goes with the square of the linear dimension, but the airplane’s volume (and, roughly, weight) goes with the cube. Wing loading (weight divided by area) gets higher, and therefore angle of attack required for level flight goes up until at some point it will stall instead. That just means that you can’t keep the proportions the same for a large plane as for a small one, not that you can’t build the large plane at all. ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [April 27, 2009, 7:56pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/13 "2009-04-27T19:56:03Z")
Yes, but at some point various other limitations on the proportions come into effect. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [April 27, 2009, 7:57pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/14 "2009-04-27T19:57:19Z")
What’s a “bemouth”? ---
**Author:** ![ElvisL1ves](https://avatars.discourse-cdn.com/v4/letter/e/5daacb/32.png) [@ElvisL1ves](https://boards.straightdope.com/u/ElvisL1ves)\ **Post date:** [April 27, 2009, 8:00pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/15 "2009-04-27T20:00:56Z")
Apparently something like a behemoth. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [April 27, 2009, 8:10pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/16 "2009-04-27T20:10:09Z")
> [@sailor](#): > > What’s a “bemouth”? It’s french, for “behemoth”. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [April 27, 2009, 8:24pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/17 "2009-04-27T20:24:17Z")
> [@ElvisL1ves](#): > > Yes, but at some point various other limitations on the proportions come into effect. Such as? I think Chronos’s “linked wing” idea argues that you can linearly scale the wingspan to more or less any dimension. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [April 27, 2009, 9:18pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/18 "2009-04-27T21:18:56Z")
> [@LSLGuy](#): > > The thing the OP linked to is a Photoshop hoax. Not sure I’d call it a “hoax.” The caption starts, “With a little imagination…” ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [April 27, 2009, 9:34pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/19 "2009-04-27T21:34:48Z")
> [@LSLGuy](#): > > The thing the OP linked to is a Photoshop hoax. > > There was a real Kalinin K-7 prototype, but somebody has created a bunch of fake pictures which scaled that airplane up from ~737 size to something a thousand feet wide, then added a couple dozen engines & little tiny people. Are you looking at the first picture, or the second? The two are quite different, I think. And as **CookingWithGas** says, the caption explains the second picture, etc. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [April 27, 2009, 9:46pm UTC](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530/20 "2009-04-27T21:46:21Z")
> [@ElvisL1ves](#): > > Apparently something like a behemoth. That word did not even occur to me. The best I came up with was vermouth. [Next page](https://boards.straightdope.com/t/maximum-size-for-a-heavier-than-air-plane/494530.md?page=2)