Hi eis4emily!
Pretty nice thought, travelling from Melbourne to London in about 3 hours. Beats the 28 hour journey I had last year! (I most certainly can’t afford business class).
The “Hypersonic” Jet that you refer to can reach its speed by travelling at much higher altitudes than regular planes (so high you won’t see or hear it from the ground!). In fact, the plane will spend most of it’s time actually ABOVE the atmosphere! It does this by first using its rocket engines, allowing it to travel really fast, then, once at maximum speed, switching on another set of engines called ramjets (which work best at speeds around Mach 3, over 3000 kmph).
Ramjets are currently only used in missiles and allow cruising at 32 kilometres in the air (compared with today’s planes which fly at around 9 kilometres)
The other cool thing about these aircraft is that they will be powered by biofuels – natural things like seaweed, hydrogen and oxygen – making them the most eco-friendly aircraft available.
A jet engine combines air and fuel and ignites it. The thing that you see on a jet engine going round and round is the pump that brings air into the engine to make it go. To get the jet POWER you need a lot of air (oxygen), which is why you need that turbine.
But imagine you’re already going really fast. And imagine you have an engine that’s like a big tube. Because the front of the tube is pushing against the air (it’s moving forwards already really fast) and the back of the tube is not, you get this amazingly large difference in pressure. The air at the front is at high pressure and the air at the back is low pressure. If you go fast enough, the front is like a shock wave, and the pressure difference is very large.
This pressure difference forces air through the tube at high speeds. What you do is inject fuel into that and ignite (well, you don’t need to keep igniting it – it’s already on fire and generally very hot). So the air gets forced through at high speed and is on fire, and then you have a little nozzle at the back that makes things even more extreme. The air coming out the back is really moving.
That’s a ramjet. It’s an engine that doesn’t work when it’s stationary. In fact you already have to me moving faster than the speed of sound for it even to think about starting to work. But once you’re going fast enough you can switch that baby on and WHOOSH.
This plane uses these special kinds of engines. They’re planning on using hydrogen as the fuel, and that’s one of the main hopes we have for “green fuel” in the future. You can get hydrogen from water if you apply sunlight and have a little cluster of molecules in there to help the process.
Ramjets have been known for ages – decades. 3 hours seems to short to me. If you add up the drinks and dinner and one movie, then a visit to the bathroom, you’re going to need at least 4 hours. 🙂
Essentially, this plane is designed to go into low earth orbit. In space there is less friction, but no air, so it has to use rocket engines. Since the earth’s gravity is stronger in lower orbits (than higher orbits), a satellite or the hypersonic jet goes really fast. The low-orbit satellites go around the world in about 90 minutes. So 3 hours from London to Sydney (or Japan) is really mostly getting up to space and coming down again. The actual travel from London to Sydney on low orbit is less than 40 minutes!
Satellites in higher orbits take longer to go around the earth. Weather satellites are so high that they take 24 hours to go around, and thus they appear to stay above the same place on earth, which also takes 24 hours to go around.
The Moon is in a very very high orbit. It takes about 4 weeks to go around the earth.
This might seem strange, but you get the same effect by swing a rock on a piece of rope around your head. If the rope is short (low or close-in orbit) the rock whizzes very fast. If the rope is long (high or far-out orbit), it takes along time to go around your head.
A hypersonic jet? I’ve been so busy I haven’t even got the time to read the news. If you hadn’t asked this question I wouldn’t have realised it was all ready made.
*goes off to look at flight prices*
Aww…this plane won’t be ready for another 30-40 years!!
There’s two things that will help this plane travel fast. The fuel that is being planned to being used in the plane is a mixture of hydrogen and oxygen designed to fire up and power rockets to fly the plane ABOVE the atmosphere. The plane will be so incredibly close to space. The special thing about flying at this height is that friction is reduced which lets the plane travel much faster than it would through air.
Hi eis4emily!
Pretty nice thought, travelling from Melbourne to London in about 3 hours. Beats the 28 hour journey I had last year! (I most certainly can’t afford business class).
The “Hypersonic” Jet that you refer to can reach its speed by travelling at much higher altitudes than regular planes (so high you won’t see or hear it from the ground!). In fact, the plane will spend most of it’s time actually ABOVE the atmosphere! It does this by first using its rocket engines, allowing it to travel really fast, then, once at maximum speed, switching on another set of engines called ramjets (which work best at speeds around Mach 3, over 3000 kmph).
Ramjets are currently only used in missiles and allow cruising at 32 kilometres in the air (compared with today’s planes which fly at around 9 kilometres)
The other cool thing about these aircraft is that they will be powered by biofuels – natural things like seaweed, hydrogen and oxygen – making them the most eco-friendly aircraft available.
0
…but 40 years till it’s ready 🙁
A jet engine combines air and fuel and ignites it. The thing that you see on a jet engine going round and round is the pump that brings air into the engine to make it go. To get the jet POWER you need a lot of air (oxygen), which is why you need that turbine.
But imagine you’re already going really fast. And imagine you have an engine that’s like a big tube. Because the front of the tube is pushing against the air (it’s moving forwards already really fast) and the back of the tube is not, you get this amazingly large difference in pressure. The air at the front is at high pressure and the air at the back is low pressure. If you go fast enough, the front is like a shock wave, and the pressure difference is very large.
This pressure difference forces air through the tube at high speeds. What you do is inject fuel into that and ignite (well, you don’t need to keep igniting it – it’s already on fire and generally very hot). So the air gets forced through at high speed and is on fire, and then you have a little nozzle at the back that makes things even more extreme. The air coming out the back is really moving.
That’s a ramjet. It’s an engine that doesn’t work when it’s stationary. In fact you already have to me moving faster than the speed of sound for it even to think about starting to work. But once you’re going fast enough you can switch that baby on and WHOOSH.
This plane uses these special kinds of engines. They’re planning on using hydrogen as the fuel, and that’s one of the main hopes we have for “green fuel” in the future. You can get hydrogen from water if you apply sunlight and have a little cluster of molecules in there to help the process.
Ramjets have been known for ages – decades. 3 hours seems to short to me. If you add up the drinks and dinner and one movie, then a visit to the bathroom, you’re going to need at least 4 hours. 🙂
0
Essentially, this plane is designed to go into low earth orbit. In space there is less friction, but no air, so it has to use rocket engines. Since the earth’s gravity is stronger in lower orbits (than higher orbits), a satellite or the hypersonic jet goes really fast. The low-orbit satellites go around the world in about 90 minutes. So 3 hours from London to Sydney (or Japan) is really mostly getting up to space and coming down again. The actual travel from London to Sydney on low orbit is less than 40 minutes!
Satellites in higher orbits take longer to go around the earth. Weather satellites are so high that they take 24 hours to go around, and thus they appear to stay above the same place on earth, which also takes 24 hours to go around.
The Moon is in a very very high orbit. It takes about 4 weeks to go around the earth.
This might seem strange, but you get the same effect by swing a rock on a piece of rope around your head. If the rope is short (low or close-in orbit) the rock whizzes very fast. If the rope is long (high or far-out orbit), it takes along time to go around your head.
0
A hypersonic jet? I’ve been so busy I haven’t even got the time to read the news. If you hadn’t asked this question I wouldn’t have realised it was all ready made.
*goes off to look at flight prices*
Aww…this plane won’t be ready for another 30-40 years!!
There’s two things that will help this plane travel fast. The fuel that is being planned to being used in the plane is a mixture of hydrogen and oxygen designed to fire up and power rockets to fly the plane ABOVE the atmosphere. The plane will be so incredibly close to space. The special thing about flying at this height is that friction is reduced which lets the plane travel much faster than it would through air.
0