Pre Spin Airplane Wheels

I cannot comment on the validity of your proposal, but I would like to comment on the big picture of "is it really needed?"

You mention saving money for the airlines, but what about safety? Keeping things simple on planes is the key to safety. Some systems are so inherently simple they cannot be improved. Messing with the fail safe brakes on a plane would require a massive payback in performance improvements to be justifiable.

Also the gyroscopic forces of all those wheels spinning would have to be measured and accounted for. Maybe this has already been done, but I just feel that this type of tech would open way to many doors for Murphy to enter through.

I would guess this tech, would pave the way to justifying less rugged tires, which is just one of the possible lubricating factors on the slippery slope you are presently standing a-top.

Sorry for being so negative, just offering my un-educated opinion.

Mevel, I went through the tire shop in San Francisco Air Port . I asked a number of theses same questions. What they told me was on average 30 to 40 landings is the life expediency of tires. They either need to be replace or recapped. Max recap is around 20 times. Skidding (Chevrons) on runway is a major problem. Un till now there is not a cost effective way to pre spin as weight of equipment is a major factor.

Military jet fighter, 2-3 landings on tires, ouch! And it is not only the tires that take a beating, Struts and the aircraft itself shake from out of round tires. And most people think it is the runway. No problem with brakes it is just a small air line in the brake pad. Just enough to release drag on the stalled wheel.

Wheel maintenance would be cut in half.

Who is this guy Murphy? He probably never made anything new in his life.

Thanks for the response. Through your help hopefully we will get it right the first time.

Del

"Who is this guy Murphy? He probably never made anything new in his life."

Murphy makes new information. He has a way of redesigning through exposing new information. His educational fees vary from 0 to infinity.

You can read more about Murphy here: http://en.wikipedia.org/wiki/Murphy%27s_law

I am curious how much you feel you can extend the life of a typical tire, when you say 1/2 the maintenance (Double life?). I assume it is dependent on how accurately you can match the tire speed to the ground speed.

Best of luck, I do admire the entrepreneur spirit and hope for the best of your venture. I wish I could add some technical advice, but I am sure others will post some before long.

There are cost benefits in using the existing system.

There are safety benefits in using the existing system.

While your idea has merit, the savings of pre-spinning aircraft tyres, do not outweigh the benefits of the present simple system.

As a system becomes more complex, an increasing number of things eventually do fail, or malfunction.

Apart from that, inertia of large airplane Companies, Airports, Insurance Companies, and lots of Lawyers are in the way of your system being adopted.

Please also see and read the Post above, by Mevel123

Rubber is cheap.

Kind Regards....

Del,

You are right 100%, seriously. Also I don't ask how old are you just to figure out if really you will see the benefits of your idea, if you succeed to patent finally (which is not so new at least for me..). I say this because I have many doubts that any manufacturer would bother now its already decided concept and replacing the well known landing system, oh God ....beuouracracy. We have to understand for how many times now that in fact all these hassles are job secures for somebody. I used to work in a big airline's maintenance division, and guess what: unfortunately I have the kind of real picture of how the things are going on. As your "negativist guy" replied, I am too a kind of "I don't think so" they will take this idea from you ....at least and very soon.

Rather I see the flying saucers replacing the airplanes, believe me it's easier!

"Rather I see the flying saucers replacing the airplanes, believe me it's easier!"

Or VTOL aircraft.

Long ago (it may have BEEN 50 years!) one of the magazines like Popular Science showed an airplane tire molded with little flaps or scoops on the sidewalls, just using the slipstream to spin the tires up. Now, back in the old days, drum brakes were still common, so they didn't need to worry about "unsticking" the pads. In any case, disc brakes can be built to utilize the spring effect of the seal around the piston to very slightly withdraw it and the pads from contact. Far, far simpler, and not patentable any longer (if it was even then). At least one of the Big Three American auto companies made self-adjusters and mechanically moved the pads in the early [for them!] days of disc brakes - late 60s or early 70s? I've seen molded cups on tires more recently, though not for aircraft. They were on mud bog vehicles, I think for mud drags.

I remember this coming up in a discussion many years ago. Apparently it had been done but owing to mismatching the speed of the wheel to the actual speed required the wear was actually greater. More than this I do not recall.

I agree, it has been done, my recollections are for the 50s or 60s. What the outcome was I haven't a clue, sorry.

"owing to mismatching the speed of the wheel to the actual speed" implies that the wheel speed was much too high, since currently the mismatch is equal to the ground speed itself. Any speed between zero and ground speed must reduce mismatch. Going over, though, increases inertia as a function of w squared (i.e., the square of the rotation rate), so going too fast by about 41% is as bad as no spin at all for mismatch, AND there is additional inertia to dissipate.

Since anti-skid systems have come into common use, obtaining the wheel rotation rate should be simple today. There is an ideal landing speed for every aircraft, perhaps 10% above stall speed, so only a single rate is needed. Lightly applying the brakes to keep the wheel from overspeeding should be easy enough, and they only need to dissipate rotational inertia, not that of the entire aircraft PLUS rotational inertia, as they do once on the ground. This will limit wear and heating issues. I'd start at stall speed for the target tread velocity, since landing into the wind reduces ground speed, offsetting that 10% factor, and the wheel's inertia is less.

Ron' Great comment you are so right it would be a simple problem to match the "wheel speed" to "ground speed".

Up until now it has not been cost effective to heat wheel storage bays that would counter the minus 50 degree temp the wheel bearing are subject to. This has, in my view been a contributing factor in pre-spinning.

Another consideration is pressure. Because of pressure changes, heating and cooling and altitude changes, Bearings get contaminated from moisture and dirt (especially brake dust) The compensator adjust the hub pressure to keep it positive (Just like a clean room). The compensator does the fallowing things with no moving parts to wear out. 1-adjust hub pressure. 2-bleeds off volume (air). 3-supply's lube oil to hub.

Del

I would have thought the whole point of friction to the tyres
would be to slow down the plane? That is, a braking (wearing)
effect, at some point, on the tyres is inevitable!

It follows to reduce or eliminate this upon contact with the ground
could mean an improved braking force, or longer runway would be required?

Just a penny worth from a by stander, as I know nothing about tyres.

jt.

Free web page on http://www.mfnb.at

jt

Ya but do you know anything about tires?

Just kidding, have a good one

The cessna citation II had a nosewheel spin up kit for the nosewheeel for operation on gravel runways

What was the reason this kit was offered?

Del

In reading this thread is seems possible that the idea of spinning up airplane wheels is one of those things that was patented long ago and expired (usually 20 years) or it's one of those many innovations that were implemented without a patent. In either case it can not be patented now. Have you done any searching of the USPTO files?

You specific method or some new detail for spinning up the wheels may still be patentable.

I have found that creative thinkers usually have lots of different new ideas, so if this one isn't what you hoped it would be press on with others!

Hello Yusef1

Thank you for your comprehensive research.

Accordingly, I have given you a Good Answer mark.

Kind Regards....

So kind. I had promised in my first post that I would find out the answers, and I never "did" find out about WWII pre-spin mods on bombers....though I did find the quote I was going by....it was in an airfield construction manual here in my library, and all it said was "once airplanes got much bigger after WW1, they had to be landed on water, because the dirt fields were getting plowed up by aircraft touching down and carving grooves until the wheels spun up. Pre-spinners becan to be employed to protect the airfields, but once the dirt fields became widely replaced by paved runways, they didn't bother with them except for heavy lift planes in the pacific." And thats about it! No reference, no real hard and fast solid facts, or even time lines, just a casual opinion from a guy who designed and built "artificial runways" all over the world.

In the process, I DID find out a lot about pre-spinning of aircraft tires, and thought I would share the info with you lot! The whole field of landing gear is a real dog since of course, the airplane does not need them to fly. So aeronautical engineers tear their hair out trying to come up with ways to reduce what is a necessary evil. In WW1, they replaced the landing gear with much lighter hooks, and would snag docking rings on derigibles. In WWII, jets were launched with undercarts which would fall away. Not quite sure why...I think they deployed a parachute to recover. Within 30 years, the f104 could dispense with its pilot, and fly its mission alone....the pilot drifting down under a parachute while his airplane completed its mission. And now, 40 years farther along, airplanes have now finally dispensed with both landing gear and any sort of life support or pilot, making them cheap enough to throw away, and cruise missles are actually becoming fancier and fancier all the time.

The field of aircraft development is long and fascinating!

Hi all

Mr.Del is involved in another discussion on another board about drilling spindles on boat trailers. Here is a link to one of the discussions.

http://boards.trailerboats.com/cgi-bin/trailerboats/ubb/ultimatebb.cgi?ubb=get_topic&f=7&t=002259#000016

One gentleman is an engineer and has made drawings and run computer simulations of what happens to the spindles when drilled. We would appreciate any input from you gentleman if you have time.