Why enlarge Heathrow Airport when you can make it smaller?

[Subbynet]

Brakes are already pretty light as they are carbon.

A video of a jumbo braking with worn out brakes.

http://momfy.wordpress.com/2011/06/...rted-takeoff-technically-incorrect-cnet-news/

Well, light is relative, as it would still take maybe 2 men to lift and fit the brake unit from one wheel of a medium sized airliner!

I think what Swisaw meant by this is instead of having 4 carbon disks per caliper, you could perhaps have 2.

 

[Swisaw]

If I'm honest, I don't know what you mean by "brake stress multiplication". Its not a term I'm familiar with. You'll have to explain what you mean by that.

The plane will need "heavy" braking systems because that's the rules. A plane must be able to bring itself to a standstill without the use of Reverse Thrusting or Air Brakes to be certified to fly. Plus if you make the brakes lighter (smaller), they'll wear out faster.

Brake stress multiplication is similar to a lever, which most of us know about. For example if you use a 2.00 metre long stick, lever, to move a heavy object with your body weight, which is 60.00kg. The stick multiplies your body weight to 2 x 60 = 120.00kg against the heavy object. The same thing happens with usual plane brakes because there is a distance between the ground under braking wheels and centre of momentum of plane body.

We can put this brake stress multiplication in a formula like this: weight of the plane x velocity x distance between the ground and centre of momentum of the plane body. In the case of my system brake stress becomes like this: weight of the body x velocity. This is a lot smaller than the usual brake stress. This is an important advantage.

Going back to the question of reverse thrusts, technically that is not possible unless the plane has extra jet engines for this purpose. Conceptually a jet engine is similar to a diesel engine. A diesel engine compresses air to a very small size. this causes the temperature of air to go very high, at which fuel sprayed on the air to cause combustion. the fans of jet engine does the same thing. So to do reverse thrusts, you have to run the fans on the opposite direction, which can act as reverse thrust but combustion doesn't take place.

 

[Swisaw]

Well, light is relative, as it would still take maybe 2 men to lift and fit the brake unit from one wheel of a medium sized airliner!

I think what Swisaw meant by this is instead of having 4 carbon disks per caliper, you could perhaps have 2.

The usual brake for emergency may never be used. So the disks may be made a lot thinner than a usual disk. additionally other parts of the brake also can be made lighter.

 

[Subbynet]

Brake stress multiplication is similar to a lever, which most of us know about.

Right I understand what you mean by Brake Force Multiplication but I think it should properly be defined as Torque?

We can put this brake stress multiplication in a formula like this: weight of the plane x velocity x distance between the ground and centre of momentum of the plane body. In the case of my system brake stress becomes like this: weight of the body x velocity. This is a lot smaller than the usual brake stress. This is an important advantage.

It seems to me you're failing to account for the torque created by the hook you need to grab the rope on the runway. According to that formula there is no external force slowing down the plane.

Going back to the question of reverse thrusts, technically that is not possible unless the plane has extra jet engines for this purpose.

No my friend this isn't correct. What happens with jet engines is a pair of flaps open at the end of the engine pushing the air back forward again. Or turbofan engines tend to split in the middle, and push air sideways (rather than backwards) using internal flaps. Propeller driven engines adjust their pitch to reverse thrust.

 

[leemason]

The question of noise has solutions. The landing runway doesn't have to be the same length as it is now. For example a new landing runway, supported with HMB, can be made 1/3 of the length of the existing landing runway, in which case landing can take place at both direction in line with wind direction. So you saved 2/3rds of the land and increased landing capacity by three times. That is not bad.

So where would this additional runway be built? You can't simply close down the existing "long" runway whilst you spend a year shortening it. Also are you really suggesting that aircraft land facing each other? What about go-arounds and overruns or indeed any safety factor at all?

What solution do you have to noise? Also noise is only one reason why they alternative runways. It's very useful to alternative runways from a runway wear perspective as well. Two take-off and landing runways also allows for some contingency so you can if you wish use either runways for landings/take-offs.

 

[MikeJ]

There's two things here. Using an arrestor hook to stop a plane, and recapturing the energy.

Arrestor hooks aren't new. They've been used on aircraft carriers for years. If anyone thought it was a practical way of stopping a passenger aircraft (which is many times more heavy than a fighter), then they'd have done so already.

Capturing the energy is a diversion. It's not relevant to whether you can use an arrestor hook to stop an A380.

 

[Swisaw]

Right I understand what you mean by Brake Force Multiplication but I think it should properly be defined as Torque?

I am self-taught person. That is way I am not familiar with certain terms.

It seems to me you're failing to account for the torque created by the hook you need to grab the rope on the runway. According to that formula there is no external force slowing down the plane.

The hook doesn't create any torque because the direction of the force of the hook acts as parallel against the direction of the plane. This happens naturally because the hook pulls back the plane although the end position of the ropes fixed to the hook may be lower than the position of the hook. If it is not for the gravity the plane moves in a direction exactly parallel to the hook and ropes. But gravity doesn't let it and it shouldn't cause any torque.

No my friend this isn't correct. What happens with jet engines is a pair of flaps open at the end of the engine pushing the air back forward again. Or turbofan engines tend to split in the middle, and push air sideways (rather than backwards) using internal flaps. Propeller driven engines adjust their pitch to reverse thrust.

Thanks, I didn't know that. It seems I misinterpreted the meaning of reverse thrusting.

 

[Swisaw]

So where would this additional runway be built? You can't simply close down the existing "long" runway whilst you spend a year shortening it. Also are you really suggesting that aircraft land facing each other? What about go-arounds and overruns or indeed any safety factor at all?

What solution do you have to noise? Also noise is only one reason why they alternative runways. It's very useful to alternative runways from a runway wear perspective as well. Two take-off and landing runways also allows for some contingency so you can if you wish use either runways for landings/take-offs.

You don't have to close down the existing runways, you use them to the end of their useful life. After that either you renew them as take off runways or as landing runways about 1/3rd of it and convert the rest to a green area or any other useful thing.

Two aircrafts can not land at the same time on opposite direction. But a landing runway can be used to land aircrafts on either direction one at a time.

Regarding the question of the noise, for example new airports could be built with my system far from big cities to replace gradually the existing ones near cities.

 

[Deleted member 138423]

You don't have to close down the existing runways, you use them to the end of their useful life. After that either you renew them as take off runways or as landing runways about 1/3rd of it and convert the rest to a green area or any other useful thing.

Two aircrafts can not land at the same time on opposite direction. But a landing runway can be used to land aircrafts on either direction one at a time.

Regarding the question of the noise, for example new airports could be built with my system far from big cities to replace gradually the existing ones near cities.

Right, you're now making a fool of yourself! Have you any experience or indeed knowledge at all of the aviation industry? You haven't, for if you did, you would know that what you are proposing is complete nonsense!

If you wish to have this statement of mine backed up, do one of two things, either contact an aeronautical engineer or pPrune the aviation forum. Believe me, you need to stop this deluded belief you have.

 

[Talay]

Knock down the 1000 or so houses and build 12 runways. That should sort out capacity issues for a good few years.

 

[Swisaw]

Knock down the 1000 or so houses and build 12 runways. That should sort out capacity issues for a good few years.

What after a good few years? Are you going to knock down more houses and build more runways? Well you can not do that after each a few good years? You have to stop some where.

 

[fisicx]

Bunging and arrerstor hook at the back of a commercial aircraft will rip it in half the first time you use it.

Take a look at the images of the arresting system below the deck of an aircraft carrier - it's a huge bit of engineering. Trying to stop a 747 would need a massive system and a full redesign of the aircraft.

It's a nice idea and the document has some good points but it's just not going to work on an airport.

I'm an aviation engineer (or at least used to be) so I do know what I'm talking about.

 

[Swisaw]

Bunging and arrerstor hook at the back of a commercial aircraft will rip it in half the first time you use it.

Take a look at the images of the arresting system below the deck of an aircraft carrier - it's a huge bit of engineering. Trying to stop a 747 would need a massive system and a full redesign of the aircraft.

It's a nice idea and the document has some good points but it's just not going to work on an airport.

I'm an aviation engineer (or at least used to be) so I do know what I'm talking about.

The braking stress of my system on the body is a small fraction of the braking stress on the body of the existing system. Brake stress of the existing system causes torque or brake stress multiplication. So if torque stress of existing system tolerated by the body the braking stress of my system shouldn't be an issue at all.

 

The braking stress of my system on the body is a small fraction of the braking stress on the body of the existing system. Brake stress of the existing system causes torque or brake stress multiplication. So if torque stress of existing system tolerated by the body the braking stress of my system shouldn't be an issue at all.

Trying to stop a 500 ton jumbo going at 150 mph quickly is probably not a good idea.

 

[fisicx]

The braking stress of my system on the body is a small fraction of the braking stress on the body of the existing system. Brake stress of the existing system causes torque or brake stress multiplication. So if torque stress of existing system tolerated by the body the braking stress of my system shouldn't be an issue at all.

No, you would need a redesign becuase you are changing the stress paths on the airframe. The main wheels are attached to the same huge great frames the wings are. If you change the method of breaking then then the stress paths will change. This will mean lots of new panels and structures on the airframe. Each aircraft type would need to be certified by the CAA/FAA and taken off-line for some months for the mnodification to be incorporated. There is no financial benefit to the airlines.

In any case, getting more aircraft landing on the same bit of tarmac is not possible. There is a minimum speration whilst in the air, you can't get more aircraft in the same flight path, any closer toghether and there is a danger of collision and the ever present free-air-turbulence.

And of course, you are asking a pilot to land on a runway that would now has a building at end of it. Just not goping to happen.

 

[Swisaw]

No, you would need a redesign becuase you are changing the stress paths on the airframe. The main wheels are attached to the same huge great frames the wings are. If you change the method of breaking then then the stress paths will change. This will mean lots of new panels and structures on the airframe. Each aircraft type would need to be certified by the CAA/FAA and taken off-line for some months for the mnodification to be incorporated. There is no financial benefit to the airlines.

In any case, getting more aircraft landing on the same bit of tarmac is not possible. There is a minimum speration whilst in the air, you can't get more aircraft in the same flight path, any closer toghether and there is a danger of collision and the ever present free-air-turbulence.

And of course, you are asking a pilot to land on a runway that would now has a building at end of it. Just not goping to happen.

Off course body frame has to be redesigned in line to new stress paths. As the braking stress of my system is a lot smaller than the braking stress of existing system, the body frame doesn't have to be as strong as before. This means body frame becomes a lot lighter, which saves the cost of building it and saves fuel cost on the long run.

It is possible to land more planes on a tarmac just like before. Whenever a tarmac becomes free another plance can land.

 

[fisicx]

Off course body frame has to be redesigned in line to new stress paths. As the braking stress of my system is a lot smaller than the braking stress of existing system, the body frame doesn't have to be as strong as before. This means body frame becomes a lot lighter, which saves the cost of building it and saves fuel cost on the long run.

Sorry but you are 100% wrong on this. The loads on the airframe in the air are exactly the same so you can't make it lighter. Remember as well that the aircraft will still have to land at all the other airports who won't have your system installed.

It is possible to land more planes on a tarmac just like before. Whenever a tarmac becomes free another plance can land.

Nope. It's not about the number of aircraft landing, it's about the minumin speration in the air. You can't get more aircraft to land as they are not permitted to fly any closer together.

Trust me on this one, I've been involved in aviation engineering and legislation for over 30 years.

 

[Subbynet]

Off course body frame has to be redesigned in line to new stress paths. As the braking stress of my system is a lot smaller than the braking stress of existing system, the body frame doesn't have to be as strong as before. This means body frame becomes a lot lighter, which saves the cost of building it and saves fuel cost on the long run.

You need to learn about Newton's laws of motion.

The braking stress (or energy) has to be equal or above that of the existing because you're trying to stop the same amount of weight in less distance. It cannot be less. This is why existing planes which use an arrestor system are strengthened and have increased weight due to the modifications, not less.

Why not less? Because planes are already designed to be as light as possible. Hence the strength of the body is less than you require, and so if you redesigned it, it would have to be heavier because you cannot ditch the existing system, this can only accompany it.

Honestly, if it was possible, the military would have done it years ago!

 

[johndon68]

What happens if the plane misses the wire (which does happen on aircraft carriers) there is no chance of it getting back in the air again and no chance of it stopping in time as the runway is no longer long enough...

John

 

[leemason]

What happens if the plane misses the wire (which does happen on aircraft carriers) there is no chance of it getting back in the air again and no chance of it stopping in time as the runway is no longer long enough...

John

That's OK. You just need a runoff filled with about a million tonnes of sand!

 

[johndon68]

That's OK. You just need a runoff filled with about a million tonnes of sand!

And lots of replacement pairs of trousers as well I suspect

John

 

[leemason]

Well if nothing else this has certainly generated a long thread.

 

[Subbynet]

Well if nothing else this has certainly generated a long thread.

But is it long enough to land a plane?

 

[fisicx]

What happens if the plane misses the wire (which does happen on aircraft carriers) there is no chance of it getting back in the air again and no chance of it stopping in time as the runway is no longer long enough...

Easy, just glue some cushions to the building they have built on the end of the short runway.

 

[Swisaw]

Trying to stop a 500 ton jumbo going at 150 mph quickly is probably not a good idea.

150mph=67m/second
500tone=500,000kg

Momentum= weight x speed. So the momentum of the plane is 500k x 67=33.528billion Newton, I am not sure if I am using Newton as the correct unit name in this case.

This is the momentum of the plane before taking brake. When the brake applied this momentum increases by the distance between the centre of the momentum of the plane and the ground under braking wheels. Assume this distance is 2.50metre. So when the brake applied the body frame receives a brake stress momentum of 33.528 x 2.5 = 83.820billion Newton.

With my system The momentum of the plane before the brake doesn't increase, it remains the same. So what does it means? simply it means with my system the weight of the aircraft can be made lighter by 2.5 times. How about that Sir Earl?

 

[MikeJ]

That's just wrong. You're assuming the weight of a plane is directly proportional to the stress in undergoes in stopping.

 

[fisicx]

The stresses on the airframe when in flight are the same whatever braking system you use. Ergo: it needs to be a strong as it currently is. You can't make it any lighter.

And you are confusing mass with weight. They are not the same thing.

Force is proportional to acceleration. If you are breaking in a shorter distance the acceleration will be higher. Which means the forces will be higher. Which means greater loads on the airframe. This is independant of the breaking system.

Note: acceleration is a vector quantity, can be postive and negative.

Plus: My mate who flies 747s said: thrust reversers do 90% of the braking. Wheel breaks only help a bit.

 

[leemason]

Also wheel breaking can only be used at relatively low speeds otherwise the breaks and tyres will overheat and the tyres probably explode!

 

[Deleted member 138423]

Swisaw, have you no shame?

 

[Swisaw]

Swisaw, have you no shame?

No, I have no shame. Got it!!!!

 

[johndon68]

Swisaw - re my question, what happens if the plane misses the wire?

John

 

[Swisaw]

That's just wrong. You're assuming the weight of a plane is directly proportional to the stress in undergoes in stopping.

Not necessarily so. But when comes to the stress of existing brake the weight of certain parts like wheel parts connecting to the body and the path of stress across the frame has to be enforced mostly by extra weight. Because there is no other ways to strengthen it. For example the bars connecting the wheels to the body frame has to be strengthened by increasing their weight. There is no other ways to do it. Remember, body frame of an aircraft can not be built with the same principle of building Eiffel Tower.

 

[Swisaw]

Swisaw - re my question, what happens if the plane misses the wire?

John

Easy, as a rule of thump draw a redline on the runway at a certain distance from the beginning of the run way. If a plane misses this redline it shouldn't land. Not only one but put a few ropes on the way between the redline and the beginning of the runway. Put the last rope over the redline as an emergency last rope. Instruct the pilots to avoid landing long before reaching the redline. This means a landing plane may be caught with more than one ropes. Additionally why not put an emergency net at the end of runways to stop landing planes overshot the runway.

 

[Swisaw]

But is it long enough to land a plane?

I swear on your life and the life of Sir Earl, which are very dear to me, it is going to be long enough to land a plane.

 

[johndon68]

Easy, as a rule of thump draw a redline on the runway at a certain distance from the beginning of the run way. If a plane misses this redline it shouldn't land. Not only one but put a few ropes on the way between the redline and the beginning of the runway. Put the last rope over the redline as an emergency last rope. Instruct the pilots to avoid landing long before reaching the redline. This means a landing plane may be caught with more than one ropes. Additionally why not put an emergency net at the end of runways to stop landing planes overshot the runway.

All of which you get on an aircraft carrier and still planes miss the wires - naval aircraft have to go to full power as soon as the wheels hit the deck so they can, if they miss, get back in to the air again for another go - this would be impossible for an airliner.

And as for the suggestion that you string a net at the end of the runway to stop something as large and heavy as a 747 or an Airbus 380, you cannot possibly be serious

John

 

[Swisaw]

The stresses on the airframe when in flight are the same whatever braking system you use. Ergo: it needs to be a strong as it currently is. You can't make it any lighter.

And you are confusing mass with weight. They are not the same thing.

Force is proportional to acceleration. If you are breaking in a shorter distance the acceleration will be higher. Which means the forces will be higher. Which means greater loads on the airframe. This is independant of the breaking system.

Note: acceleration is a vector quantity, can be postive and negative.

Plus: My mate who flies 747s said: thrust reversers do 90% of the braking. Wheel breaks only help a bit.

OK, so 10% of the braking is done by the wheels. Let me to requote the post of Sir Earl:

Trying to stop a 500 ton jumbo going at 150 mph quickly is probably not a good idea

150mph=67m/second
500tone=500,000kg
If reverse thrusters do 90% of braking, it will mean they also reduce the speed by 90% to 6.7m/second.

At this speed the momentum of the plane becomes 500k x 6.7 = 335.28Million Newton.
This is the momentum of the plane before taking wheel brake. When the wheel brake applied this momentum increases by the distance between the centre of the momentum of the plane and the ground under braking wheels. Assume this distance is 2.50metre. So when the brake applied the body frame receives a brake stress momentum of 335.28 x 2.5 = 838.20million Newton. This momentum multiplication must have necessitated the extra strengthening of the body by extra weights, masses.

This means my point is still valid. With my system The momentum doesn't multiply at any point. So the extra strengthening by weight becomes unnecessary. So this is as clear as daylight an aircraft with my system becomes lighter.

Lets go back to reverse thrusters. These reverse thrusters act like a parachute at the back of the plane. They must be very heavy and very expensive to make. With my system you don't need them.

 

[Subbynet]

My friend your sums are all over the place. Out by orders of magnitude. 500k x 6.7 is not 335 Million (its 3.35 Million)...

You also need to understand, that although your system places less torque on the aircraft (landing gear), it will need extra TENSILE strength, because you're exerting a different force on the airframe!

This is why the aircraft needs strengthening, because its not designed for this type of force. Whereas the landing gear is designed to absorb torque!

Also, the reverse thrusters place no real extra weight on the aircraft, its negligible at most. It's just a couple of extra flaps.

You need to understand that Force/energy doesn't just disappear, it just converts into something else and dissipates (in many ways, heat/sound/movement etc) but it never just disappears. Its how you dissipate the energy which is important.

 

[Swisaw]

My friend your sums are all over the place. Out by orders of magnitude. 500k x 6.7 is not 335 Million (its 3.35 Million)...

You also need to understand, that although your system places less torque on the aircraft (landing gear), it will need extra TENSILE strength, because you're exerting a different force on the airframe!

This is why the aircraft needs strengthening, because its not designed for this type of force. Whereas the landing gear is designed to absorb torque!

Also, the reverse thrusters place no real extra weight on the aircraft, its negligible at most. It's just a couple of extra flaps.

You need to understand that Force/energy doesn't just disappear, it just converts into something else and dissipates (in many ways, heat/sound/movement etc) but it never just disappears. Its how you dissipate the energy which is important.

You are right. It is 3.35Millions but this doesn't mean my point invalidated. My points remain as valid as before.

Yes, aircrafts by their nature designed to tolerate my system because my system behaves exactly like reverse thrusters.

Reverse thrusters bear 90% of brake stress, which means they must be very expensive to make and have a large amount of weight.

Who said force/energy disappears? and what it has to do with our discussion?

 

[Subbynet]

You are right. It is 3.35Millions but this doesn't mean my point invalidated. My points remain as valid as before.

It makes a huge difference. If the reverse thrusters do the main bulk of braking, then this massively reduces the stress on other components. That's why they do it, to reduce wear on other components.

Yes, aircrafts by their nature designed to tolerate my system because my system behaves exactly like reverse thrusters.

No, they're not designed to tolerate your system and its nothing like reverse thrusters - they apply a force through the wings - a strong point on a plane. Your system doesn't touch the wings and your system will apply an even greater force than the engines themselves!

This isn't a new invention, you can check this out yourself with some research in to aircraft that actually have arrestor hook systems. It already exists, its been done and tested, the aircraft that use this system are strengthened! (Weigh more, use more fuel, fly less distance - you can read up about all this on Wikipedia, its a fact!)

In fact I'll do the research for you!

Lets take the latest Aircraft for the RAF that's in development now. The Lockheed Martin X-35. They have developed 3 different versions of the plane for different uses, and please note the differences.

"F-35A, a conventional takeoff and landing (CTOL) variant. It is the smallest and lightest version"

F-35B "The U.S. Marine Corps will use the F-35B to replace both its AV-8B Harrier IIs and F/A-18 Hornets with a design similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems."

"Lastly, the F-35C, a carrier-based variant, will replace the "legacy" F/A-18 Hornets and serve as a stealthy complement to the F/A-18E/F Super Hornet. It will have a larger, folding wing and larger control surfaces for improved low-speed control, and stronger landing gear for the stresses of carrier landings."

http://en.wikipedia.org/wiki/Lockheed_Martin_X-35

Find any aircraft that uses arrestor hooks and it will say the same thing.

Reverse thrusters bear 90% of brake stress, which means they must be very expensive to make and have a large amount of weight.

Reverse Thrusters are the existing engines directing some of the air forwards, they're part of the engine itself. Instead of it blowing backwards, it blows the air forwards.. No extra equipment is required.

Have a read..

http://en.wikipedia.org/wiki/Thrust_reversal

Who said force/energy disappears? and what it has to do with our discussion?

You don't seem to understand where your force is applied and how. You keep stating the existing plane can take the extra force without modification but its not designed too!

Honestly my friend, this is not a new invention, it was done nearly 100 years ago.

 

[Swisaw]

It makes a huge difference. If the reverse thrusters do the main bulk of braking, then this massively reduces the stress on other components. That's why they do it, to reduce wear on other components.

No, they're not designed to tolerate your system and its nothing like reverse thrusters - they apply a force through the wings - a strong point on a plane. Your system doesn't touch the wings and your system will apply an even greater force than the engines themselves!

This isn't a new invention, you can check this out yourself with some research in to aircraft that actually have arrestor hook systems. It already exists, its been done and tested, the aircraft that use this system are strengthened! (Weigh more, use more fuel, fly less distance - you can read up about all this on Wikipedia, its a fact!)

In fact I'll do the research for you!

Lets take the latest Aircraft for the RAF that's in development now. The Lockheed Martin X-35. They have developed 3 different versions of the plane for different uses, and please note the differences.

"F-35A, a conventional takeoff and landing (CTOL) variant. It is the smallest and lightest version"

F-35B "The U.S. Marine Corps will use the F-35B to replace both its AV-8B Harrier IIs and F/A-18 Hornets with a design similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems."

"Lastly, the F-35C, a carrier-based variant, will replace the "legacy" F/A-18 Hornets and serve as a stealthy complement to the F/A-18E/F Super Hornet. It will have a larger, folding wing and larger control surfaces for improved low-speed control, and stronger landing gear for the stresses of carrier landings."

http://en.wikipedia.org/wiki/Lockheed_Martin_X-35

Find any aircraft that uses arrestor hooks and it will say the same thing.

Reverse Thrusters are the existing engines directing some of the air forwards, they're part of the engine itself. Instead of it blowing backwards, it blows the air forwards.. No extra equipment is required.

Have a read..

http://en.wikipedia.org/wiki/Thrust_reversal

You don't seem to understand where your force is applied and how. You keep stating the existing plane can take the extra force without modification but its not designed too!

Honestly my friend, this is not a new invention, it was done nearly 100 years ago.

Wait a minute!!! with my braking system you can use almost the same principle of building Eiffel Tower to build body frame of a plane. In the case of Eiffel Tower, the way it is built
helps it to carry a lot of weight while it uses less material, less weight, to keep the frame of the tower very light.


The bulk of braking of aircrafts now is done by reverse thrusters, which are fixed along the back of each wings on both sides. It is logical the body frame must be strong enough to bear the increased weight of both wings when reverse thrusters go to action and when they go to action their weight increases by many times. Let me ot requote the post of Sir Earl:

Originally Posted by sirearl
Trying to stop a 500 ton jumbo going at 150 mph quickly is probably not a good idea.

150mph=67m/second
500tone=500,000kg


At this speed the weight, momentum, of wings when reverse thrusters go to action increases by 500k kg x 67m/second. So the wings must have a lot of extra strength over flying strength to bear the extra braking stress, strength.


With my my system, you may need to redesign body frame but you don't need add extra weight to it. My system behaves exactly like reverse thrusters. So now instead of bearing the increased brake stress of wings, the body frame bears the increased brake stress of my system. As the aircraft no longer needs the use of reverse thrusters, it gets red of them and needs lighter wings. Hypothetically the wings can become lighter by 67 times. But this is only a hypothesis. Nevertheless it should become lighter at least by two or three times. This in addition of getting rid of the weight of reverse thrusters.


Conceptually hook arrestors are not new but technically mine is different. It is a major improvement. Additionally the recovery of brake power is completely new as stated before by mikeJ.