an invention - need retired engineer to collaborate with.

[diano455]

Ok, I might have invented something...
what is it? No I'm not telling you :=

- well the jist of it is a wheel/ground speed equalising device.

1: My method works.
2: I think it's better than any other method I've researched so far (I don't think I've seen everything though... need an engineer who knows)
3: It's not been done before "my way", very few patent issues so far (but I havent seen every design so can't say for sure yet).


It is (bar the motor that will spin the wheel(s) up to the groundspeed) passive and isn't hardwired into any part of the plane, a failure of this part would simply result in the return of wheels skidding during landing, the plane would revert to the old way, I see no way a failure of the device would result in an unsafe landing, apart from the anti skidding effect will be lost, the plane would revert to a normal landing, instead of the super smooth, skidless, (brakes INSTANTLY available) landing that my device offers...

I reckon I can get the wheelspeed within 2/3MPH of the groundspeed upon landing with my device, maybe within fractions of a MPH with some clever maths - givng braking + steering much quicker after landing, reducing stresses and shock on every part of the plane, as well as extending tyre life by... a lot - the wheel(s) should really "touch";)down, not skid and burn down...



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IQ 152, free time 100%
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[On-MarkBob]

Many devices have been tried before, from anemometer style cups on the wheels to motors to drive them. All been dicarded. The initial decelleration caused by wheel spin-up critcally reduces airspeed so that the brakes can be applied early. Weight on wheels is very important after touchdown. Spinning the wheels even a bit can have a significant effect on the landing roll. Further, there is a problem called 'unsprung weight'. Most operators move towards carbon brakes, not just because of the better braking but also because of a significant weight advantage, included in this advantage is that of unsprung weight, the mechanics of which include inertia and the load on unsprung components of which only the tyres absorb the shock loading.

[TURIN]

Does this system involve, well, er, you know, some sort of conveyor belt?:}

[Edgar Jessop]

Back in the mists of time I used to work for a wheel OEM and we used to get these ideas proposed to us about one every 2 months. None was ever taken up. Why? Partly from past experience, the ones we did look at were generally variations on a theme, which had been tried and failed years ago. And partly because there is no need for them. Despite the big puff of smoke (and chirp noise the movies love to dub in!) this has very little effect on the wear of tires. By far the biggest factors influencing wear are braking and turning. In any case tire lives are not generally seen as a problem within the industry, requiring engineering work and carrying extra weight to 'solve'.

Sorry to appear to pour cold water on your idea diano but it would be a shame for you to put a lot of effort into something only to find it had been tried and rejected years ago. But if you do want to go ahead good luck to you and I hope the above caveat may be of some use.

[muduckace]

Sounds like you need money, and influence. Sadly IQ and free time will not help you much.

Anti-skid is a necessity and a normal function.

"(bar the motor that will spin the wheel(s) up to the ground speed) passive and isn't hardwired into any part of the plane"

You would have a hell of a time passing this over any CAA, if it can't be monitored give up now. If it is in addition to.. aircraft landing spec's are not a variable in Reg's.

Just giving it straight as I see it, I love ingenuity

best wishes,


MUD

[diano455]

Not hardwired, it has controls, monitoring, yes.
But it is not connected to any other device on the plane

The power for the wheel, be that 2-litre diesel engines on each wheel, or somerthing more suitable (I have a sweet method of spinning the wheel up, might make the wheel lighter, or the wheel could be made lighter.

It is pretty much stand-alone,

I suppose it could take readings from the planes instruments, but it really doesn't need them, would probably only knock it miles off it's multi-sourced position and speed readings

I reckon I can get it measuring speed to around 0.01MPH or better, it will likely be so damn good.

have to do some testing,

Landing without the drag of the wheels, truly, as if the ground weren't moving
, just resting the plane down on the suspension.

G-meters would show smooth lines in all directions and smooth transitions.

This thing could even help get the plane going perfectly* straight and in line with the runway, that's probably its limit,

I see the point of the inertia of the tyres and wheels helping slow the plane.
That will be lost without adding masses of complexity I suppose, but to me it seems a bit of a by-product, a cheap and dirty (if indeed accidental) method of getting some supplemental braking.

The method means As soon as the tyres touch down the brakes can start to be applied, the microsecond the suspension is compressed the brakes come in, the opposite of launch control.

[Fargoo]

Doesn't sound feasable or neccesary to me, for a start you need to spin up the wheel and therefore the brake rotor assembly just before touchdown

As the brake assembly takes up the entire inner of the wheel and the anti-skid transducers and brake fans take up the inside of the axle it doesn't leave anywhere to mount such a system.

You say it won't interface with any other aircraft systems but as it would need power and monitoring both of these would need to be wired into the leg and aircraft again adding weight.

Lastly, there doesn't seem to be any benefit to having such a system. Autobrakes are generally active at 80 knots wheel spin up speed anyway so pretty much come on at touchdown. Tyre wear is a non-issue as already discussed.

In short , more complexity (and inherent costs) , more weight and no discernable gains.

Sorry to put the idea down but unless you come up with some real calculated savings that outweigh the cost of installation, maintenance and fuel to carry the extra weight - your idea is dead before it leaves the ground.

[Matt_]

when you start putting costs together, certification, parts, labour and post fit servicing ect, ask your self if its really cost effective.

Think how much a tire costs?

Not intending to be rude, but if such a system was seen to be of as much benifit to the operator as you seem to think, one of the big names would of already been on this band wagon.

dragon den style, "for these reasons, im out"

good luck if you decide to pursue it :}

[helimutt]

TURIN, now that is funny, but please don't start that old chestnut off again, please!:)

[onetrack]

Geez, you blokes are pretty tough on old diano, with his brilliant idea. Just imagine... with his invention, you've not only got the wheels spinning to within microwhiskers of the aircraft touchdown speed... but you've also got several extra giant gyros in operation, to help stabilise the aircraft on touchdown! :D
Diano, this is brilliant... let me in on the idea, and I'll give you shares in my new invention - flame-retardant matches.... :suspect:

[muduckace]

One more hurdle I see here is the fact that fuel lines are generally placed in a area to protect them (stated you need a diesel motor on the gear or equivilant) , there are several general rules concerning them. You would need a fuel source on the landing gear that would need to be serviced or fuel lines that pivot at the top of the gear and have lines running down the gear. I see alot of potential for disaster. Landing gear are often as naked on the front as possible with a rubberized coating in some cases to protect the strut/trunion and real busy on the aft side with electrical conduit and hyd lines.

Also comes to mind another "what if", how could you guarentee that one side does not run slower or fail totally, what happens if one side fails just short of landing. The yaw torque on TD could make for some hair raising and dangerous landings.

Not trying to kill your idea just giving you some facts the way I understand aircraft to help you design better or realize your idea just may not work.

[Blacksheep]

The method means As soon as the tyres touch down the brakes can start to be applied,But we don't want the brakes to be applied as soon as the aircraft touches down, we want smooth, even deceleration. Have you heard of auto-braking systems? In commercial operations, at touch down the truck rotates level, the tilt sensors trigger ground spoiler deployment, reducing lift to put more weight on the wheels and creating lots of speed reducing drag. They also enable thrust reverser deployment. The aircraft slows aerodynamically, initially at greater than the auto-brake selected deceleration rate. As the aircraft slows and aerodynamic braking becomes less effective, the autobrake system applies the brakes progressively to achieve the selected deceleration rate without any wheel skidding. Passenger comfort and tyre/brake wear are maximised by using the optimum deceleration rate for the runway length and surface conditions. There is simply no need to get on the brakes as soon as the aircraft touches down. The less you use them, the longer they last.

(Of course, if you really want to stop quickly, you could do away with brakes altogether and use a hook, as they do on aircraft carriers, but the passengers wouldn't find that a good idea, methinks.)

[eagleskinner]

I must admit I have toyed with this idea as well over the years - but as others here say before me: weight penalty vs. cost effectiveness. I've considered scooping the slipstream over vanes and all sorts. But always the penalties outweigh the benefits. The idea has been on the books at least since before I made a tech-suggestion to my employers in 1988. It was rejected then because someone else had already suggested that to accelerate the wheels to a minimal speed differential would reduce tyre wear on landing.

Tyres are indeed expensive - but not too expensive by comparison to carrying the mechanisms needed to accelerate the wheels.

I even thought about cooling the landing areas with a waterspray. Of course you have to recycle as much as possible, but even there, the money folk say not viable - but that extra bit of aquaplaning could compensate the roll speed difference between the wheels and the tarmac.

Sound iffy? Not really; the big stuff often lands on wet runways and the water does reduce initial touchdown friction.

BUT the biggest problem with innovation is that Aerospace FiCos are the most conservative people around. Period. Even designers these days are very cautious. Non-revenue mass is anathema to the commercials.

There's even serious thought being given to wheelless planes to save the weight of flying with an undercarriage. Pre-positioned landing dollies... :eek: The only reason airlines have pilots is to have someone responsible at the scene of an accident before everyone else. If autopilots eventually get there, you can bet Ryanair will be the first to ditch their seat-stick interfaces.

Sadly I have to tell you that these kinds of ideas have been thought about for decades. The only reasons there arent (m)any patents are because there's not enough return on investment.

YET.

So go for it and prove it. ;)

[muduckace]

I even thought about cooling the landing areas with a waterspray


I thought of waterspray for a whole other reason. Gusty days absent of rain to help predictive windshear work alot better.