Assuming you have billions in disposable income and honestly would be interested in such a thing…
Would it be possible to build an aircraft (I’m thinking dreamliner in size) with a swimming pool one could swim in midflight?
Hypothetically speaking how would a swimming pool in an airplane work taking into account turbulence, etc.
Is it completely impossible to be done?
I doubt there’s any way to control that much shifting water and still be able to swim.
Not to mention the weight of the water and pool materials.
A pool 6x20x3 ft would contain roughly 22,000 lbs of water.
It is theoretically possible but very impractical. You only have to think of it as a sealed liquid container that opens during stable flight. That isn’t a trivial requirement but aerial tankers are fairly common for military and firefighting use and they are generally much smaller than a Boeing Dreamliner let alone and Airbus 380.
Here is a calculator to figure out pool volume:
I figured a generous, rectangular, flying pool would be 10 x 30 feet with a depth of 3 feet at the shallow end sloping down to 8 feet. That will easily fit into a modified aircraft body as long as you get the center of gravity right but the weight is very high.
It takes 12,375 pounds of water to fill a pool that big and the water alone would weigh a little over 100,000 pounds but a very large airliner like a Dreamliner can easily lift that much (but not a lot more once you account for the pool hardware, plane and fuel).
You would have to re-engineer it into a flying tanker with a very strong and retractable top for the pool that could be opened in flight with a baffling system to suppress excessive water movement during minor turbulence. You wouldn’t be able to open the top at all except during almost perfect conditions.
It wouldn’t work well at all and the plane wouldn’t be good for much else but you could get a few swims out of it. If money is absolutely no object, it may be the best 400+ million dollars you ever spent.
If that sounds too steep, we are having a special on much cheaper alternatives this week.
If I’m reading the chart here correctly (Boeing 787 Dreamliner - Wikipedia), a dreamliner can carry about 120,000 pounds. At 8.3 pounds per gallon, that would be about 14,000 gallons of water. Even if you assume that half of that weight would need to go to pool materials, that allows for a good sized pool: maybe 4 feet deep, 30 feet long, and seven across. Build it into a sealed, watertight compartment (basically a cube, with sides all the way to the ceiling), and I don’t see why you couldn’t have one.
You probably couldn’t swim during takeoff or landing without getting banged around quite a bit, but during level flight and even mild turbulence (remember, it rarely even spills water glasses) you’d probably be OK.
I’m not sure what the effect of the water shifting during takeoff acceleration would be, but it would be predictable in direction. Landing would probably matter less, since the plane is on the ground before the deceleration really starts. I’m not sure if the weight shifting backwards along the line of travel during takeoff would make the plane hard to fly or not (similarly on turns). You might have to design the plane for it, specifically. You could mitigate this somewhat with a hard cover that snapped over the water to hold it “in place” during maneuvers, though you obviously wouldn’t be able to swim in it during those times.
You could almost certainly solve some of these problems if the plane were on a treadmill, though.
The largest fire-fighting plane could carry around 100 tons of water.
That would give you a pool of around 5m x 2m x 10m which is decent.
As mentioned above though, storing that as a “pool” rather than in properly distributed, baffled, balanced tanks is another matter entirely.
I’m thinking that the optimum shape to prevent sloshing would either be a sphere or maybe some sort of parabolic curve - does a closed tank with an entry hatch still count as a ‘pool’?.
I don’t know for sure that it’s actually been done but small pools like a hot tub have been proposed to be put in planes. They would have a removable lid to seal them up for takeoff, landing, and turbulence. If you want to swim you’d do that with a pump system so you can swim in place. Such things are not huge.
This would be cool. You could do this on NASA’s “vomit comet” and actually simulate swimming on the moon.
Youtube upload of what happens to a large airliner when a load shifts on take off.
I’m with Shagnasty on this one. You’d need a fully fledged tanker with a removable lid to the tank you could slip through. Doesn’t sound particularly luxurious. You’re not going to get something recognizable as a recreational pool into an airliner.
How about if the water were not in the pool at take-off and landing but only when the plane was at altitude?
The weight, as mentioned above, is large but not insurmountable. Especially not for a powered lap pool like this: http://www.endlesspools.com/ The minimum plausible size is a lot smaller than the fairly spacious models shown on that site.
The hard problem is sloshing. Others have already mentioned it, but here’s the correct term and a good cite: Free surface effect - Wikipedia
A small enough tank installed near the CG could be left open provided the sides were high enough to contain the sloshing. Alternatively you’d need a watertight cover or simply store the water in properly baffled tank(s) until needed then transfer to the pool for swimming, then back to the storage tank(s) for descent & landing.
My IMO bottom line: Readily doable for a lap tank. Probably not doable for a backyard swimming pool size. Silly in either case.
Then you’d need a separate tank as large as the swimming pool.
Best scheme is a pool with a retractable cover - so during takeoff, landing and rough air, it becomes a sealed tank.
I was thinking of a number of smaller tanks with baffles distributed around the aircraft.
How are you going to implement baffles?
It’s truly …puzzling.
I have one of those endless pools, and you can make the current irregular in them even through normal activities in the pool, much less the sloshing of a plane. So I doubt you’d be using it for its intended “infinite distance” swimming purpose, but it could make for an interesting resistance exercise. Those pools also need a LOT of powered hydraulics, and the filter system does NOT like being exposed to air, so you’d have to find a way to make sure it was always underwater.
It’s off topic, but I love my endless pool. We bought a house with an original model pool in it that hadn’t been used in years, and basically retrofitted it to all the modern equipment in the original pool bed. It’s close to zero maintenance (just takes liquid bleach as a chlorine source) unless you’ve got troublesome water chemistry where you live, needs about $150 a year worth of filters and ionizers (and you can re-use the filters if you like), and a new motor ($500 installed) every three or four years. More importantly, the “swim current” thing actually works – you can swim more or less indefinitely in a 7x14 foot space without constantly running into walls and such. I was swimming “long distance” in it the first use of the pool – it doesn’t take any learning time. The only downside is that you can’t vary your speed while swimming – you have to move at the current’s speed for as long as you swim. (The current speed is adjustable, but it takes several seconds and can’t really be done while you’re swimming).
I think we can all agree that the water should be dumped before landing. For someone spending this kind of money, the lost water is hardly going to break the bank.
Find the nearest wildfire to dump the water on and I bet your accounting staff can figure out a way to write the whole thing off as a charitable contribution…
My concern would be takeoff- and landing - when the aircraft is severely nose-up.
I have several concerns -
Sloshing - the last thing you need is the center of gravity actively changing back and forth during critical maneuvers, like having a few elephants running up and down the plane ( or worse, side to side). You need a solid no spill, no slosh room cover and/ insertable baffles for maneuvring.
Change of center of gravity. I recall reading an accident report where a flying boat aircraft had a small leak, the bilge was not pumped out before takeoff. As it took off, the water ran further and further back until it nosed up and stalled high enough to be fatal.
As others mentioned, during turbulence you want to keep a lid on. Hopefully, you can anticipate turbulence. One big drop, instead of an injury where the drink cart flies up, you get the contents flowing all over the plane to cause chaos and ruin the center of gravity causing a stall. So the pool room would also have to be small, water-tight, and the deck should drain back into the pool.
wasn’t there a movie based on a Mordecai Richler book about a guy who disappeared while swimming in a lake; found his body on the hills where the forest fire was 20 years later?