Reel Physics: The Avengers - Helicarrier

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um ....

The rotor speed was faster then what you mentioned. The Iron man suit wasn't able to keep up at speed and we've seen those suits are capable of super sonic flight.

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

Ed.:
Doesn't a ducted fan have more lift than an open open one not sure how much it reduces top losses massively but at the same time the bit where it flies on three engines. Though that sidesteps the masses of water question.

Yea, I think the rotor assumption was off. duct-ed fans are much more efficient at moving air.
Also there is the weight issue. A great deal of the weight in an aircraft carrier is the fuel they carry. If you wanted a flying one you could probably due without, say half. Also the two nuclear reactors probably weigh a bunch, shaving off another one of those could save some weight. (Also being in the air means no fresh coolant, so its possible there are none aboard)
Addendum addendum, the bottom of a Nimitz and the bottom of the heli-carrier are shaped a lot differently, mainly the helicarrier is shallower, so there's probably a weight saver there too. There is a lot below the waterline of a Nimitz, including the reactors.

There's a lot you could try to do that would save this, but it would be a lot of work and analysis that I can't find myself doing either. Anyway, if you need a win, you need a win.

Edits galore:
Oh! And there's the rudder and the propellers! Those weigh a bunch too!

Lunar Templar:
um ....

The rotor speed was faster then what you mentioned. The Iron man suit wasn't able to keep up at speed and we've seen those suits are capable of super sonic flight.

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

You don't want to have your blades move supersonic-ally. Even ducted. It's not a good idea. That assumption was accurate. Also, a lot of the suit's thrust would be used to keep Tony in the circular path, centripetal acceleration an all that. The suit's top speed in a circle probably isn't equal to the straight line top speed.

Scarlet Johansson. Hoefficient of friction.

Aww yeah.

Ho-efficient and Hara-Karrier?
H-tastic bloopers! ^^

Seriously, keep it up as always!!!!

But.... but..... but....

You forgot about the uhm.... the SUPER ROTORS. YES. They have ULTRA MEGA SCIENCY BLADES that can exert 100 times the normal lift!

And erm.... THE HULL IS MADE FROM.......... erm.... SCIENCE METAL. That weighs ONE TENTH steel and you DON'T need more!

HAHA! Foiled you again!

It's all totally true. I read it in this one comic this one time.

It's weird, a submarine would have been smart.

Sir Broccoli:
But what if we made the carrier out of styrofoam?

Actually, the most probable material would be Nanotube graphite, which has almost identical properties of steel, yet the weight ratio would be .02 instead.

Given that Shield has the resources to "outfit every man woman and child on earth with 24 karat solid gold underwear in 24 hours" I believe they would have access to build a carrier out of this superlight real material.

TheSchaef:

At 4:22, it was stated that a **single rotor** (emphasis mine) generates ~64,000 kN of thrust.

That number was for all the rotors combined, not just one.

someonehairy-ish:

TheSchaef:

At 4:22, it was stated that a **single rotor** (emphasis mine) generates ~64,000 kN of thrust.

That number was for all the rotors combined, not just one.

That's probably true. But can you point me to something that corroborates that explanation? Because if you go to the time marker I indicated in the part you quoted, they say that is the thrust generated by a single rotor.

It's all fun until "aluminum". You're missing an i. If we're going to get all pedantic and nit-picky about units and force and whatnot, name the materials properly. The population in the US may be used to saying it that way, but it's wrong.

The population in the US is used to saying it that way because that's how it's correctly spoken and written in our language, English(US). I do love the sound of the word aluminium, though. It's so essentially British.

Quick wikipedia search says ducted fans can be up to 94% more efficient,
so ~64,000 kN x 1.94 = ~124,000 kN
add 4 (50%) more fans ~124,000 kN x 1.5 = ~186,000 kN
then take into account that ducted fans are also capable of a Higher RPM as well and you could make up that remaining ~20,000 kN you would need for a carbon fiber/aluminum craft.

Also for ducted and so many blades, you probably should be using Momentum theory/volume of air moved calculations instead of Blade Element Theory/each blade is a wing calculations.

Okay, two questions:

1.) How big must the rotors be to make it actually work ?

more interesting question:

2.) How much fuel would the rotors/engines use up to hold the carrier in the air ?

I'm much more interested in how much energy they would need to generate to keep that thing in the air for weeks at a time.

TheSchaef:

someonehairy-ish:

TheSchaef:

At 4:22, it was stated that a **single rotor** (emphasis mine) generates ~64,000 kN of thrust.

That number was for all the rotors combined, not just one.

That's probably true. But can you point me to something that corroborates that explanation? Because if you go to the time marker I indicated in the part you quoted, they say that is the thrust generated by a single rotor.

Go to 3:27. They factor in all of the rotors early on in the equation by calculating the area of all the rotors put together, rather than finding the lift generated by one rotor and multiplying it alter.

This is the first one of these I want a follow-up to. The speed of the rotors needs to be adjusted to account for overcoming Iron Man's speed, and ducts vs open makes a world of difference.

I would like to thank you for giving me a reference on the density of CF vs aluminum.

Lunar Templar:
um ....

The rotor speed was faster then what you mentioned. The Iron man suit wasn't able to keep up at speed and we've seen those suits are capable of super sonic flight.

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

Sure, Iron Man has been shown to break the sound barrier... when traveling in a straight line in open air.

I really doubt he'd be going his top speed in a confined space around a turn that tight. I haven't exactly calculated the G's he'd be doing on something like that, but at the very least I'd be surprised if he managed to stay conscious let alone avoid just dying outright.

Vivi22:

Lunar Templar:
um ....

The rotor speed was faster then what you mentioned. The Iron man suit wasn't able to keep up at speed and we've seen those suits are capable of super sonic flight.

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

Sure, Iron Man has been shown to break the sound barrier... when traveling in a straight line in open air.

I really doubt he'd be going his top speed in a confined space around a turn that tight. I haven't exactly calculated the G's he'd be doing on something like that, but at the very least I'd be surprised if he managed to stay conscious let alone avoid just dying outright.

well it IS comic book tech where talking about here, certain rules of reality where beaten over the head and tossed into traffic awhile ago.

sides, i'd think he'd be able to hit top speed that situation, what with less wind resistance due to being s close to the rotors and all.

but then ^^;; the math for that is WAY over my head, I'm just applying what i know from watching the movies and making logical assumptions based on displayed ability's

Lunar Templar:

Vivi22:

Lunar Templar:
um ....

The rotor speed was faster then what you mentioned. The Iron man suit wasn't able to keep up at speed and we've seen those suits are capable of super sonic flight.

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

Sure, Iron Man has been shown to break the sound barrier... when traveling in a straight line in open air.

I really doubt he'd be going his top speed in a confined space around a turn that tight. I haven't exactly calculated the G's he'd be doing on something like that, but at the very least I'd be surprised if he managed to stay conscious let alone avoid just dying outright.

well it IS comic book tech where talking about here, certain rules of reality where beaten over the head and tossed into traffic awhile ago.

sides, i'd think he'd be able to hit top speed that situation, what with less wind resistance due to being s close to the rotors and all.

but then ^^;; the math for that is WAY over my head, I'm just applying what i know from watching the movies and making logical assumptions based on displayed ability's

Wind resistance would be mostly unaffected by proximity to the blades: since it's constantly flowing through the blades it's going to be roughly similar to the density of actual air (there will be some factors based on the velocity of the air, reducing the air density by a small amount). Atmospheric density affects the speed of sound, and the ease of getting to high speed... most of the time.

The problem is that Iron Man is flying in a circle. To do so, he needs to exert a constant force away from the centre of the rotor (pushing himself towards it) to prevent himself from flying in a straight line and crashing through the wall. One of my pet-peeves for this film is the fact that there is no apparent source of Iron Man's centripetal force, but let's file that up as an invisible thruster. However, this force has to be equal to m.(v^2)/r. (m being Iron Man's mass, v being his velocity, r being the radius of the circle). That required force is going to get bigger and bigger as Iron Man's speed goes up, so he'll have to devote most of his power towards sustaining it. In a straight line, he has no such concern. Therefore his circle speed is going to be substantially less than his straight-line speed. I seriously doubt that he, and by extension the rotors, are going super-sonic. I'm not even sure that super-sonic rotors would work properly... (Insufficient time for the air to flow through, so it acts like a flat disc, providing no thrust at all. That's an educated guess on my behalf though.)

If you want to make the heli-carrier work, use the comic book physics. It's main generator is probably similar to Iron Man's arc reactor or the Tesseract. That cuts a substantial amount of weight out, and removes the fuel concerns. If that turns out to not be enough, then add in a lightweight but strong comic-book metal, and maybe a comic book version of the Mass Effect's mass reducing tech, and you're there. Completely impossible in the real universe, completely plausible in the Marvel-verse.

of COURSE! it's so SIMPLE!

First of all; that's a very good dolphin sound right there...
Second; you should really use another soundtrack while you're talking maths. The one you use works quite well for the examples (i.e. clips) and conclusions, but not in the middle of the show/calculations...

JarinArenos:
Pretty sure the blade-speed was significantly faster than a blackhawk, seeing as Iron Man couldn't keep up with it once it approached top speed, and we know he's super-sonic capable.

Of course, a supersonic hellicopter blade is well beyond my aerospace engineering knowledge, and I suspect that it simply wouldn't work at all...

Because internet:
I am not an aeronautical engineer, but i have observed their work
the following are my thoughts and considerations on that work but may not be fact.

i'm pretty sure all modern turbine jet engines utilize supersonic blades but they are a completely different design the ones seen on the avenger's carrier

The RAF fitted the Merlin HC3A with winglets on it's blades because they realized the tips were breaking supersonic speed and causing excessive drag and noise ( the vortex rolling off the edge of the blade )
so it's certainly possible to increase the speed of a heli blade at-least with modification
i know nothing about modifying a 'fan' to supersonic speed, though
you'd need to talk to an engineer at BAE systems or the like to find out if such a thing is even possible
just 'shrug' to that one.

what i do know is this is why boat propellers look like screw threads or scoops, high speed heli blades are thin and spread apart it's to encourage your medium between the blades and prevent the vortex from touching other blades or you just end up wasting allot of energy to create an inefficient centrifugal vacuum

that's the problem you need to solve, at-least

also, my take on iron man flying between blades is that in any real situation where the blades were slowly accelerating toward him if he touched it he would just be scooped out the bottom i'm not even sure you could maintain any kind of stable flight between fan blades to begin with but the director said so..
maby that's just another instance of 'reel' physics

Aeon_COR:
Quick wikipedia search says ducted fans can be up to 94% more efficient,
so ~64,000 kN x 1.94 = ~124,000 kN
add 4 (50%) more fans ~124,000 kN x 1.5 = ~186,000 kN
then take into account that ducted fans are also capable of a Higher RPM as well and you could make up that remaining ~20,000 kN you would need for a carbon fiber/aluminum craft.

Also for ducted and so many blades, you probably should be using Momentum theory/volume of air moved calculations instead of Blade Element Theory/each blade is a wing calculations.

actually, you make a good point and Also.. just because it's as large ( or slightly larger than ) a nimitz carrier that doesn't mean it's automatically as dense it could be significantly lighter if it were intelligently built

you don't see many aircraft with icebreaker strength hulls for example
considering the technology throughout the rest of the carrier some simple structural modifications wouldn't be much of an ask
and with your revised thrust calculation
i think this would be the result:

http://www.youtube.com/watch?feature=player_detailpage&v=eOZI3I6uAX4#t=17s

( ok, it's a model but still that proves the theory is sound at least )

One thing I didn't get was why was it supposed to be O-so-much-more dangerous for Thor to fall to earth inside a big can as opposed to just falling? Seems to me it would be about the same either way--and since he's fallen to earth from great heights many times, it would not be a big deal.

What is this "Aluminum" of which you speak? it clearly some sort of metal that grinds my ears... it's called Aluminium!

shiajun:
It's all fun until "aluminum". You're missing an i. If we're going to get all pedantic and nit-picky about units and force and whatnot, name the materials properly. The population in the US may be used to saying it that way, but it's wrong.

Manthraxx:
What is this "Aluminum" of which you speak? it clearly some sort of metal that grinds my ears... it's called Aluminium!

Mmm...no.

In point of fact, it can be spelled or pronounced in either form. For that matter, you can even refer to it as "alumium".

If Sir Humphry Davy hadn't been so damn flaky when naming his discovery, and had Webster not been so popular at the time (in the US, especially), AND had the scientific community not been so keen on having an -ium at the end of everything, it is very likely that we would all be calling it Aluminum. (or possibly even alumium)

I've always found it a tad pretentious of the English to tell other parts of the world that they're pronouncing aluminum incorrectly, when both forms have been acceptable for roughly two centuries.

Oh well...

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
O.T.
A tad predictable on the conclusion, obviously, but fantastic episode none-the-less. Keep up the great work guys!

See, Avengers was so forgettable I didn't remember any such ship in that movie. Though I think they had some trouble with some engine or something. Who cares.

There was a flying carrier in Doctor Who though. Similarly stupid I guess.

At 6:18, they're talking about the "thermal Hoefficient for Scarlett's hotness." I saw what they did there.

There's a lot of assumptions here that feel off to me.

Is it possible, when you encounter a case of reel physics, to illustrate what *would* make it work? Once you have the equations, it should be fairly easy to say "if we underestimated the lift of the rotors" or "if the carrier is made of something stronger than steel but 4 times lighter" or anything that makes it work.

someonehairy-ish:
Go to 3:27. They factor in all of the rotors early on in the equation by calculating the area of all the rotors put together, rather than finding the lift generated by one rotor and multiplying it alter.

I can buy that. But why would they make it a point of saying that is the thrust generated for ONE of the rotors later?

I'm not saying you're wrong, I'm just saying the way they described their calculations was very confusing.

Love show, still thinks its impossible, but would be interested in seeing the numbers crunched based on ducted fans vice open rotors.

But the question is, is it possible that the rotors were just supplementing something else that was also propelling this giant into the air? Remember, this thing exists in the same universe as a cube that apparently opens dimensional portals. I am also being entierly serious, to, since I saw a special on TV talking about future modes of travel, and how we will one day build ships that glide on waves of energy, or something bizarre like that. In any case, I just assumed the rotors where just there to add momentum to something that was already being pushed.

TheSchaef:

someonehairy-ish:
Go to 3:27. They factor in all of the rotors early on in the equation by calculating the area of all the rotors put together, rather than finding the lift generated by one rotor and multiplying it alter.

I can buy that. But why would they make it a point of saying that is the thrust generated for ONE of the rotors later?

I'm not saying you're wrong, I'm just saying the way they described their calculations was very confusing.

Maybe they got confused themselves and said one rotor by accident? Idk, but they definitely factored all of them in at that stage.

On the units: to make this even more scientific, you could mention that you were using US tons which are equal to 2000pounds, compared to metric tons, which are equal to 1,000 kg. This leaves your european watchers confused ;-)

But these non-metric units are a curse anyway, especially when they share the same name (ton), so I'm glad you're giving SI conversions. My professors think it's funny to give us US units once in a while...

Owwy even if you double it its still not enough with 100% carbon fiber, if go by a factor of 5 it becomes doable with a amulimin and CNF mix. And even then its hard to do without breaking the sound barrier. And do not forget you have staff,planes and water to deal with so you would need something closer to the all steel value to take off. I am all for an anti gravity device turning the ships total wight to 25-40% that makes it more plausible.

Lunar Templar:

Secondly, it was able to stay aloft with only 3 of it's turbines active.

so ... might wanna recheck the math

You do realise that the Helicarrier isn't real? :P

The writers could have made it stay aloft with one turbine and it wouldn't make a difference to the math because they were making it up.

loved this episode. thanks for making this series, i look forward to it every week

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