Improved Aircraft Landings

I would guess that making the wheels spin would make the plane less maneuverable. This is bad when trying to land.

Wow, you even cited a reference in your answer too. If that doesn't doesn't deserve a GA, I'll eat my hat.

Please, sign up to this blog. The more intelligent and coherent people we can gather here, the better.

My guess is that the added complexity, weight and costs make it less attractive than periodic tire replacement.

Challenge question.

What would be the difference between reply #3 and reply #2?

Helloooo ... Echo ... desert wind.

Quantity versus quality.

OK, ok ... I'm off topic.

P.S. Definition of desert wind.

A wind blowing off the desert, which is very dry and usually dusty, hot in summer but cold in winter.

I remember 20+ years ago asking people "in the know" this question. If I recall correctly the spinning would do very little good unless it is at the perfect speed. Perfect is pretty hard to hit. In trying to get it close you would add weight and complexity to the plane. If you are not perfect then the weight might cause efficiency harm and the system might not do much good.

The tire area, especially on retractable gear of a carrier aircraft, is not a nice place to add weight and complexity to.

You also have the problem of something going wrong. This is especially bad if that something going wrong either damages the aircraft that the system is installed on or leaves FOD on the runway for someone else to hit.

The tire spinning may be done someday, it might even be done a little now. But, in a "lawsuit lottery" world it is much easier to add operating expense to the buyer than to add a purchase cost burden and a lawsuit liability burden to the manufacturer/seller.

I read a story a few weeks ago about a pro hockey player from Michigan that bought a limo from an Ohio car dealer. One night when the hockey player was not wearing a seat belt the hired limo driver fell asleep at the wheel and caused an accident. The hockey player was injured and could not play hockey any more. The hockey player sued the car dealer and the financial losses forced the car dealer out of business. If our current legal system allows this kind of nonsense then the legal liability of putting a new fangled tire spinner thing on an airplane is out of the question (especially if hockey players are allowed to buy airplanes).

PS I'm not against hockey. Any game where you can be hit by a speeding puck, smashed by a big stick, cut by sharp blades, squished by a check and hit in the face by other players sounds like a bloody good time.

Hello Guest ...

What does " FOD " stand for ? I guess it's something like " Foreign Object Detritus " ??? I am a pilot and I have never heard of this term. I remember a foreign object on a runway in France resulted in an engine fire that brought down a Concorde which ultimately led to the retirement of the the entire Concorde fleet from service. I wonder if airport operators like the black marks ( mostly rubber ) being deposited on their runways and they have to be cleaned since they might might reduce braking efficiencies. I suppose pilots like using these marks besides the numbers as landing targets ?

FOD = Foreign Object Damage. An object introduced to the system from outside the system, e.g. safety wire sucked into a running turbine engine.

DOD = Domestic Object damage. An object introduced into the system from within the system, e.g. compressor blade liberates from disk causing downstream damage in the engine flow path

There is plenty of information on the web (including various patents). Any commercial design would have to be super reliable and not interfere with plane's aerodynamics or weight distribution. Not very realistic for large planes like the 747, but perhaps for smaller planes. This is also totally ignoring the biggest hurdle - getting such a major design change approved in an industry tighter than even the auto industry.

Try Googling "Aircraft tire wear" for more information.

I believe this question was asked before.

In fact I think it may have been to this question what got me my first, or one of my first GAs.

I forget now exactly what I wrote.

It has been now at least two years.

http://cr4.globalspec.com/thread/17808#comment184580 will give you at least one of the previous passes through this topic.

especially on aircraft carrier landings.

Oh yeah that's a priority Just reduce a little ordinance or fuel

tailhooker??

I remember a student asking the teacher,(retired Naval aviator, WW2 through 50's), this question in an aeronautical Engineering class, back in the mid 70's.

His answer was , that it had been tried, but it was preferable to have the tires "bark"on landing , which added a braking effect, small but necessary . Spinning the wheel before contact would increase the roll distance.

But there may have been a similar device on the Cutlass, it had a 13 foot front strut and My fuzzy memory seems to recall it having one to prevent the strut from being damaged?

Spot on packrat. Though Guest has done most of this and I was just going to lurk; from a piloting point of view, you want that deceleration - and that 'bark' is felt. It counts off as the main gear is grounded - and the amount of 'bark/bite' indicates the amount of breaking available (wet, oily, icy, soft etc).

When this pre-rotation thing comes up, as it does regularly, craft fitted rob pilots of those important inputs.

However; when it's too fast and it kicks the gear forward.

Most main gear 'folds forward' (to some degree). Ummmmmmmm?

Your Air speed might be in a narrow band, but ground speed is a function of head or crosswind component. I've landed at virtual VTOL in "brisk" conditions.

It also removes/complicates, the option to 'touch' not quite locked gear on the deck to lock it.

Nose wheel? who cares - but if it 'locks forward' and 13 ft long- 'faster would be an advantage'.

Main gear is a different thing all together. Not all landings are "By the Book". Die or spend fu#k-all % of overall maintenance buying rubber - it's a choice?

Hi Kyzine,

I concur with what you said , especially the last , even if the rubber is expensive, it's cheap compared to pranging an airframe.

Packy

Thank you for all the good answers. I just wasn't aware that it had been tried and dismissed. At least I know where to go when I want the answer.

Weight is fuel, it is cheaper to replace tires than the fuel weight a spinning device would cost.

This concerned me some years ago and the best explanation that I found is that it is a bit like a dragster warming its tyres before a race, the tyres are designed to grip at temperature and the skid, as they come up to speed, does that nicely. Just watch a race car or bike try to go round corners with cold tyres, and on an aircraft coming down from cruise altitude, the tyres are very cold (I wouldn't want to lick them). I know it seems a waste of rubber, but as one other correspondent noted the added weight of a spin-up device is added cost, complexity and weight - all undesirable.