they could use the downwash to generate steam and so drive a generator. Seems silly to waste all that heat.
It's now official. The new generation of high-tech hovering aircraft - namely the famous V-22 "Osprey" tiltrotor and the upcoming F-35B supersonic stealth jump-jet - have an unforeseen flaw. Their exhaust downwash is so hot as to melt the flight decks of US warships, leading Pentagon boffins to look into refrigerated landing …
Pump water (from the sea) filter out the divers and fish, send the water through a metal heat-exchanger seperated form the deck by a centimeter or so, and the gap can also have water sprayed in there I guess.
Why re-frigerate? that will cause the metal to buckle as well I would have thought.
Of course having a proper armoured deck would also do the trick, but who does that any more?
I can't find the video, but this guy made a 15mm plate out of his paste, puts it to his face, and holds a blowtorch against it for over 10 minutes. No appreciable temperature change behind the mask, material still strong.
This guy has been made bankrupt many times, yet his ideas and inventions are staggering. Give the guy some R&D money. Hell, send him to the Skunk Works. His wacky ideas will do your ailing boffins a world of good.
Oops! He's Canadian. Sucks to be you, I guess :D
Cover the deck in the same ceramic heat-absorbing material NASA has been using for decades on their craft.
Except of course, the US military complex has a horrible case of "not invented here" and will no doubt reject any solution so simple and elegant for something that takes 20 years to develop, and at the point of service introduction, it'll be outdated, outmoded, just in time to grant its developer a renewal contract.
Mine's the one lined with simple ideas for complex problems - that have been rejected by bureaucratic nonsense and whiney (self-)interest groups.
...but wouldn't the Brits have fixed this problem long ago when they had to deal with Harriers performing vertical landings on their pocket-sized carriers?
Either that or the US Navy can fit a giant oven glove* on the landing pad.
*They can put a camouflage pattern on it if the usual daisies aren't sufficiently Oooh-rah for the Marines.
According to a quick google search, the V-22 is powered by two 4474kW engines.
This means that if you were spraying water onto the deck and would allow the water to reach 80degC, you'd need just over 17kg of water per second per engine. For an aircraft carrier that's probably not too problematic. That's a total of 34 litres per second or just over 72cfm of waterflow. And that's assuming that the engines are just being used to churn out masses of heat. Which they're not- some of their power is going into actually moving the plane. Height from the sea for a big carrier's probably about 50M, meaning that you'll also need a decent amount of pressure to shift that water column as well as the pressure required to have it vapourised and fired quickly through the exhaust gasses.
So to design a saltwater-safe pump that'll pump that amount of water from the sea up to the flight deck of, say, one of the massive Yank Nimitz carriers, plus some design work for a water-scoop that'll work when it's going at full tilt or when it's stopped you'd need... ooh, say a hundred grand. Actually, make it a cool quarter-million. It has, after all, got to be extensively tested and made reliable- plus there will be ship re-engineering costs for removing waste water (unless they've got an Olympic curling team armed with very big squeegees or decide to just boil it off- meaning a smaller cfm pump required but a more dangerous working environment- and that's the last thing a carrier needs!).
Actual cost to the taxpayer will probably be nearer $50M per unit...
Come to think of it, it shouldn't cost the Taxpayer anything. The damn things should have been designed to work properly. It's not like Aircraft carriers are a new idea they couldn't have foreseen!
How about using a material based on the current deck coating but made sufficiently porous so that water could be pumped up through it creating a continuously replenished coat of water under the aircraft? You may well be able to apply vacuum to remove excess water when you're done to avoid a too-slick surface.
OK, where's my billion dollar contract?
Didn't the people who designed this thing think about that? If they did, why hasn't anybody listened to their previous research? Oh, the military is part of the government, that explains it -- since according to most Merkins the government can't do anything right, which implies the US military sucks too.
I mean, I have no clue about aircraft (or other) design, but first thing I would think about a bloody VTOL airplane is: "how hot is the exhaust", and "what surfaces can it be used on".
Oh well, too simplistic, so I must be wrong.
When they were testing Phantoms on the Eagle they had metal plates strapped to the deck which they cooled down with fire hoses after each launch (the blast deflectors weren't up to the job) and that was using full afterburner. I think the main problem with the Osprey is that the exhaust is always pointing at the deck as you can't tilt the engine on the ground so any time spent on deck engines running waiting for people to get on/off etc is going to be heating the deck, for the JSF it should be less of a problem as it only points at the deck during the landing.
Re: NASA heat shielding: Yes, NASA has been dealing with heat issues for 50 years. And their two solutions are single-use ablative heat shielding and re-usable tile that is so mechanically fragile that a piece of insulating foam going at (relatively) the same speed is enough to damage it fatally.
I'd suggest that a combined approach would be ideal: Start with the Russian brickyard approach mentioned above, using several layers of something designed to combine the impact resistance of paving brick and the thermal resistance of firebrick and with a textured upper surface for skid-resistance. HOWEVER, the brickwork layers should be designed with channels between the bricks where water could be flushed at need for cooling. Should the water system fail for some reason, the brickyard would probably be enough for intermittent take-offs and landings, with the water-cooling needed for high-traffic conditions.
NASA have had the same problem for years when they light up one of their sky rockets. A big hole in the ground and f'ing big water pumps seems to work. Might need a bit of adaptation for a ship...
As for "hard" marines, I doubt they would last a winters day in Newcastle in the national dress of t-shirt and shorts.
The solution to V22 deck heating is probably found in the water the ship is floating in. Provided an elevated landing surface and force sea water under it to hold the temperature under 200 degrees. But keep in mind that the V22 is simply a disaster waiting to happen and should be discontinued anyway!
..reusing tiles from the soon-to-be redundant Shuttles. Think there's a few left in some Texan fields someplace, but that's an old story. (Wasn't Rockall^H^H^Hwell involved with that?)
But, when the Shuttle takes off, they spray it's bottom with water (ooer, missus) for both sound/vibration reduction and cooling. IIRC.
(Does it really need a bunch of nerdy Vulture commentards to come out with this?. Nah. They've thought of it already. Maybe)
The obvious solution is for the carriers to be adapted to be submersible thus solving the problem of deck cooling.
Of course it will mean some modifications to the aircraft but that will be a government stimulus to the aircraft building industries and an investment in vital submarine VTOL stealth aircraft R+D capability.
is to add vertical vents around most of the engine itself.
See, it doesn't need to vent much downward to land--the propellers do that job already--but with this addition, they can achieve greater amounts of stability in landing as well. All they have to do it close it tightly during flying procedures, and they're golden.
Granted, there's plenty of (very warm) prop-wash if they do this, but the heat won't be so focused.
I still vote on NASA's ceramic shuttle plating--it's less trouble than this. Don't they layer insulation foam underneath as well?
"""it doesn't need to vent much downward to land"""
The jet outlet adds useful amounts of thrust, diverting it sideways would reduce the load by several hundred Kg.
Water would not stay in place long enough to do any cooling of the deck. The jet stream is several hundred mph.
Fire bricks may absorb the heat slowly but they will stay hot for a long time and adding water will crack them.
big yes to the NASA tiles , I have one here ... Its called LI-900 Shuttle tile Insulation or in full Lockheed Insulation 9lbs per cubic foot. Its dense but brittle and can handle the temps mentioned handling over 100 repeated temp cycles. from -170 Deg F to 2300 deg F.
There is a black borosilicate glass coating that is applied to the outside surface of the tile to re-rediate 90% of the heat. This coating also protects the porous tile material from rain, fluid contamination ( not sure about jet fuel) salt spray and handling damage.
I think it would need to be strengthened a bit more to cover the rough landings experienced at sea.
Thanks to NASA and my trip to Kennedy SC for that info.
Typical poor thinking. Buy aircraft, but don't even think about or test what they are meant to fly off. After all, they didn't have 20 years to worry about hot aircraft exhaust for this thing...!
I am not an engineer, but I see two major problems with the water idea said above. First, sea water is salty and salt water and delicate engine components are best avoided! Second, that much heat will turn the water into steam and the pilot won't be able to see the deck or anything else for that matter. You might get away with that in Afghanistan and the dust, but not with a moving deck which could have a nasty habit of smacking your aircraft out of the sky.
The shuttle tiles idea, although logical, is probably a non-starter as well. If NASA have to freak out every single time a tile falls off, how it is meant to cope in rough weather and with several tons hitting it on a regular basis? I think the carrier might end up carrying more tile than spare parts to replace it all the time!
The logical solution is surely for the new surface to deflect the heat. Of course this leads to the problem of the V-22 then being fried by its own engine when it comes in to land! Which realistically means that the only solution is for the new surface to absorb the heat, but then transfer it somewhere else... A bit like a CPU heatsink.
Thus I have found the IT angle! ;)
Good point - the jolly old Limey's and the aforementioned jar-heads (oorah) have been operating them 'low tech' Harriers from carriers for years and unless there's been a fantastic cover-up there doesn't seem to have been a problem.
In which case, why are the JSF's and more especially the V-22's running so much hotter that it's now a problem? Personally, I'd be looking at running some water pipes (need a desalinisation plant, because steel pipes+salt water isn't a good mix) under the flight deck - or at least under the parts where the planes are landing - to carry the waste heat away before the deck melts. Job done?
Being Defence procurement I assume that they'll go for something exotic - rather than simpler solutions, like increasing the thickness of the flight deck in the relevant areas, (and yes I do realise that this'd do horrible things for the balance/seakeeping).
Cheers to the ones pointing out how dangerous half an idea can be.
Space shuttle heat tiles are so fragile they crack with next to nothing hitting them. Land a plane on them and see what happens.
The water cooling that shuttles apparently use at launch. They don't. You're thinking of the sound suppression system they use - it dumps water under the exhaust to muffle the enormous shockwaves that are emitted and reflect back into the shuttle structure.
Just two points.
The tiles on the Shuttle might well be heat-proof but they're insanely fragile. You can scratch one with your fingernail, hell they're even dented by raindrops. So there's no way they'd survive having a plane drop on them.
To answer Pyros point above. No, there's small flexible felt pads under each tile, but they're there to allow the aluminium skin of the Shuttle to expand and contract without popping the tiles.
And Nomen Publicus's question about the water dumped on the Shuttle pad during launch. That's not there for heat protection, it's a sound deadening system preventing shockwaves bouncing off the concrete apron and tearing the rocket apart.
Won't happen without using existing technology. No need for super-cooling when the ceramic tiles from the Space Shuttle, as several have mentioned, will work. But that's my point: heat-resistant materials have been around for centuries. Most varieties of mineral-based compositions will do the trick.
But the old school solution, asbestos, probably won't be making a comeback.
How about using telescopic or swinging booms to dangle aircraft over the side of the ship where the deck melters can be fired at will and reversing the process for landings? Something similar was possible with biplanes and dirigibles in the 1930s, and we haven't gone that far backwards since then, have we? Thinking about it, the Osprey might be better suited to perching atop a boom rather than dangling off it, what with the rotors and all. All that dangling about does seem like a faff though, so I propose a new breed of carrier. You lease yourself a couple of container ships or tankers from these ghost fleets we keep hearing about, put a couple of nice big hatches in the deck, and stick your concrete landing pad in the hull below those, using the rest of the space as your hangers and armouries and what have you. Hey presto, you've made yourself an el cheapo aircraft carrier in disguise like the double hard stealth ninja death from above tight northern bastard you are. Pays for itself the first time you see the look on Jonny pirate's face as he pulls alongside and your jumpjet peeks back out over the yard rail giving it the yoohoo.
The insides of coal fired power plants are pretty damn hot. They remove the heat (and make steam to run generating turbines) by running water through steel tubing. Source of water - check. Somewhere to dump the steam - check (overboard, vent it sideways). Strong enough to land an airplane on? Hmm, welded square steel tubing? I think so.
Think again.. water turns into what when heat is applied.. and a pilot needs what when taking off and landing? (hint: visibility)
Just look at a NASA rocket taking off. And no, that is not just smoke on launch. That is massive amounts of water being turned into vapour.
Also ask heli pilots (especially military) what they hate about doing landing and takeoffs in desert and snow conditions.. A white out and loosing the horizon as reference when landing.. with too little time to transition to IMC and instruments when you that low. Lots of accidents happened that way.
If water is to be used, it needs to cool the deck from underneath. It would be just stupid to expose the heat of the engines directly to surface water,
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