Pre-rotating of aircraft wheels before landing?

[dr_gn]

Why not simply make the runways out of rubber, and the tyres out of concrete

[anonymous-user]

dr_gn said:

Why not simply make the runways out of rubber, and the tyres out of concrete

Better still, why not make the runway out of a conveyor belt, that electric motors can drive or brake. That way planes don't need ANY wheels, can be assisted on take off, and energy can be re-cuperated on lander as well.....

[dr_gn]

Max_Torque said:

dr_gn said:

Why not simply make the runways out of rubber, and the tyres out of concrete

Better still, why not make the runway out of a conveyor belt, that electric motors can drive or brake. That way planes don't need ANY wheels, can be assisted on take off, and energy can be re-cuperated on lander as well.....

Or make really long, interlinked runways all over the globe, and do away with the wings too.

[eccles]

Max_Torque said:

For large passenger airframes, i believe the tyre life limitations are primarily load/fatigue based, rather than "tread wear" in most normal cases (when operating from long, well surfaced 1st world r/w). Each time you land or take off, those tyres are supporting hundreds of tonnes of airframe traveling at nearly 200mph, and those stresses lead to a slow degradation in the tyre integrity. And whilst you could make a tyre strong enough to last indefinitely, it would be so heavy and bulky it would cost you more in terms of payload & drag!

I'd love to know what you base this on.
In the many wheel changes I've done over the years I've never changed a wheel because the tyre was fatigued!
Every single one was due to wear, damage or manufacturing fault.
The only time fatigue in the carcass is a limiting factor is in deciding how many times you can use it in a remoulded tyre, and as for being heavy and bulky.... they already are! extremely!

[Hooli]

dr_gn said:

Max_Torque said:

dr_gn said:

Why not simply make the runways out of rubber, and the tyres out of concrete

Better still, why not make the runway out of a conveyor belt, that electric motors can drive or brake. That way planes don't need ANY wheels, can be assisted on take off, and energy can be re-cuperated on lander as well.....

Or make really long, interlinked runways all over the globe, and do away with the wings too.

With planes you can drive yourself?

[JoeBolt]

eccles said:

In the many wheel changes I've done over the years I've never changed a wheel because the tyre was fatigued!

I have. I've replaced wheels on which the tyres were life expired and the wheels due 'bay service'. (Based on calendar time).
This was on a Jaguar going through a lengthy major servicing and modification programme, following long term storage.

I can't speak for every aircraft and every operator, but on the many military aircraft types I've worked on, the tyres were lifed items (as were the wheels and brake units). However, I think it would be rare on a fixed wing aircraft in service, for the tyres or brakes to reach the end of their life before they were replaced 'on condition' due to wear or damage. It would probably be far more likely on a helicopter.

[sneijder]

C0ffin D0dger said:

For electric taxiing the cost savings are far from "minimal". The development of driven wheels for aircraft is being taken very seriously: http://www.greentaxiing.com/index.html

Doesn't mention spinning up the wheels when landing though so that may not be viable / sensible.

http://www.greentaxiing.com/overview.html

I don't quite get this, they push pack with the APU powering the wheels, and then taxi electronically after ?

[williamp]

Another thought: the tyres are big and heavy. Getting them to rotate would give them huge momentum like a gyroscope. I can imagine the forces could unsettle the aircraft when co ing into land. Not what you want...

[chuntington101]

Max_Torque said:

Better still, why not make the runway out of a conveyor belt, that electric motors can drive or brake. That way planes don't need ANY wheels, can be assisted on take off, and energy can be re-cuperated on lander as well.....

A bit like a bigger version of what's used in wind tunnels to test f1 cars?

http://m.youtube.com/watch?v=KC0E0wU6inU

[dr_gn]

chuntington101 said:

Max_Torque said:

Better still, why not make the runway out of a conveyor belt, that electric motors can drive or brake. That way planes don't need ANY wheels, can be assisted on take off, and energy can be re-cuperated on lander as well.....

A bit like a bigger version of what's used in wind tunnels to test f1 cars?

http://m.youtube.com/watch?v=KC0E0wU6inU

For all these undercarriage-less proposals such as catapults and moving runways/trolleys etc.:

Who pays for the infrastructure, maintainance and huge amounts of energy needed for systems in every airport with the capacity to handle aircraft with no undercarriage? Don't forget all airports or airstrips potentially used for emergency diversions would also need equipping.

[carreauchompeur]

dr_gn said:

Driven mainwheels for taxying are currently being investigated (to save fuel), and these would also allow pre-rotation and regenerative braking for landing.

This to me makes excellent sense, so much fuel must be wasted using jet propulsion in a slow speed environment, as well as having the engines spun up just waiting etc.

[marksx]

Just put Chinese tyres on. They never wear down.

[Jam Spavlin]

chuntington101 said:

A bit like a bigger version of what's used in wind tunnels to test f1 cars?

http://m.youtube.com/watch?v=KC0E0wU6inU

Thanks for posting the link chunington really enjoyed it!

[Evoluzione]

marksx said:

Just put Chinese tyres on. They never wear down.

That's already been tried.

[eccles]

carreauchompeur said:

dr_gn said:

Driven mainwheels for taxying are currently being investigated (to save fuel), and these would also allow pre-rotation and regenerative braking for landing.

This to me makes excellent sense, so much fuel must be wasted using jet propulsion in a slow speed environment, as well as having the engines spun up just waiting etc.

I suppose the simplest answer could be one that's already been used since the dawn of aircraft....a towing arm and a tug!

[sneijder]

eccles said:

I suppose the simplest answer could be one that's already been used since the dawn of aircraft....a towing arm and a tug!

Towing isn't generally included in ground handling contracts, although the charge is less than 250-300Kg of fuel....

Airports would grind to a halt though, you'd need service roads for the taxi ways. I'd guess the taxi ways are a lot tougher than the apron, there'd be safety pins breaking and holdups non stop.

BA have tiny remote controlled tugs in maintenance, could beef that design up and cockpit crew could drive themselves via camera ?

[eccles]

sneijder said:

eccles said:

I suppose the simplest answer could be one that's already been used since the dawn of aircraft....a towing arm and a tug!

Towing isn't generally included in ground handling contracts, although the charge is less than 250-300Kg of fuel....

Airports would grind to a halt though, you'd need service roads for the taxi ways. I'd guess the taxi ways are a lot tougher than the apron, there'd be safety pins breaking and holdups non stop.

BA have tiny remote controlled tugs in maintenance, could beef that design up and cockpit crew could drive themselves via camera ?

So your answer to putting down a return road for vehicles and adding a small fee for ground handling, is millions of pounds in research and then certification! ok.

[anonymous-user]

sneijder said:

BA have tiny remote controlled tugs in maintenance, could beef that design up and cockpit crew could drive themselves via camera ?

Already been trialed!




[i]TaxiBot Approved To Enter Service With 737 Fleet

by Charles Alcock
November 3, 2014, 11:57 AM -

The European Aviation Safety Agency and the Civil Aviation Authority of Israel have issued a supplementary type certificate (STC) for the TaxiBot aircraft towing system developed by Israel Aerospace Industries (IAI) in partnership with France’s TLD and Lufthansa LEOS. Plans call for the semi-robotic, pilot-controlled system to begin commercial operations with Lufthansa at Germany’s Frankfurt Airport by the end of November.

The initial STC—the first for a system of this type, according to IAI—covers use of TaxiBot with Boeing 737s under FAR 25 rules. Unlike a standard no technical objection (NTO) approval issued by the airframer, the STC covers the use of the equipment for all phases of push back and taxiing to and from the runway. Airbus expects soon to issue an extended NTO for its A320 fleet that would cover the same scope of operations.

Trials of TaxiBot have proven its ability to taxi a fully loaded 737 at 23 knots, which IAI claims is the fastest speed achieved by a taxiing system to date. Rival systems are under development by a Honeywell-Safran partnership and by WheelTug.

IAI claims TaxiBot offers significant savings in fuel consumption and engine emissions. According to the company, a 737 or A320 burns about one metric ton of fuel (1,250 liters) in a typical 17-minute taxi operation. By comparison, the TaxiBot only consumes around 25 to 30 liters for the same operation. An aircraft taxiing under the power of its own engines would emit around 7,040 pounds of carbon dioxide, compared with less than 132 pounds with the TaxiBot.

The pilot retains full control of taxiing, operating the TaxiBot via the aircraft’s tiller and brake pedals, and the system requires no modification to the aircraft. Crews perform coupling and decoupling of the TaxiBot on the taxiway, close to the runway.

In trials conducted by Lufthansa, the airline found that it achieved savings of 37 percent in terms of the time taken to get in and out of airport gates. According to IAI TaxiBot project director Ran Braier, the equipment also reduces the exposure of aircraft engines to foreign-object damage during the taxi process.

IAI has yet to announce a base price for the TaxiBot but said that airlines will achieve a return on their investment in less than 18 months as a result of fuel savings and reduced cost of operations.
[/i]

[RizzoTheRat]

dr_gn said:

Why not simply make the runways out of rubber, and the tyres out of concrete

Funnily enough something similar has been tried for carrier landings. Eric "Winkle" Brown has a piece on it in his autobiography which I'd recommend to anyone with passing interest in aircraft.

https://www.youtube.com/watch?v=f7Lu6LEQ0zo