wheel run-up idea

[BigJETS]

I was wondering if anyone has ever thought about some type of system that would spin the wheels when they were extended so as to reduce wear on touchdown. Such as, fins on the wheel assem. that would drive each wheel as it sliced through the air. Ive been thinking about it some time, Has it already been covered?

[Lu Zuckerman]

To: Big Jets. .. .The run up idea has been tried on many occasions to include placing aerodynamic flaps on the tires to get them spinning prior to touch down. Many systems have been tried and all have been eventually rejected.

[RadarContact]

One good reason against passive, aerodynamical solutions would be that, although maybe beneficial before landing, you'd have to really brake those wheels after takeoff before retracting them.. .Why? Ever tried to spin up a bicycle wheel real fast and then turn it by 90 degrees...?

[BigJETS]

Good point re: rigidity, but could you spin down using the same idea? I guess if it has been tried before, then it may have had some value? One disadvantage I can think of already may be the possibility of small parts falling off. Im curious to why it has been abandoned. Thanks.

[BOAC]

Aired at least 12 months ago and I told the story of the Lancaster which had rather bad precesion in a trial during the war. Have a search back.

[exeng]

Radar Contact,. .. .All the airliners I've operated do 'brake' the wheels during retraction. That would be B737, B747, B777 and A320. I think all other current Boeing and Airbus types do as well.. .. .Regards. .Exeng

[willbav8r]

Doesn't the Concorde set the mains spinning (forward) before touchdown?

[Willit Run]

Either Goodyear, or Goodrich tried this many years ago, and the gyroscopic forces made it very difficult to control!!. .Thats a bad thing!

[exeng]

Time to close this topic I think.

[Bellerophon]

willbav8r. .. .No

[Wino]

tire wear is not from touchdown suprisingly. 90 percent of it is from slow speed taxing around corners and whatnot.. .. .The smoking tire on landing looks spectacular but is actually inconsequential. (I hate that I can use longer words than I can spell). .. .Cheers. .Wino

[Checkboard]

Nosewheel spinup kits are still used on gravel kit conversions for business aircraft types - stops you kicking gravel into the airframe and engines.

[pigboat]

Thought Cessna tried that with the Citation and gave it up as a bad idea? <img border="0" title="" alt="[Confused]" src="confused.gif" />

[BigJETS]

Thanks for indulging me. I know its a logical idea but I was just curious. I know tires arent cheap. . .. .keep em flyin

[RadarContact]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> All the airliners I've operated do 'brake' the wheels during retraction. That would be B737, B747, B777 and A320. I think all other current Boeing and Airbus types do as well.. . </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Sure they do. But why put that extra energy into the rotation while braking the wheels? That was my point... <img border="0" title="" alt="[Wink]" src="wink.gif" />

[exeng]

Radar,. .. .I see your point, but I believe that we are talking about relatively 'small' amounts of energy here. And with A/C that have carbon brakes apparently the brake wear is not an issue; but that has been debated before.. .. .Regards. .Exeng

[411A]

Lets see, the Lockheed Constitution and the Consolidated-Vultee (Convair) XC-99 used motors to spin up the tyres prior to touchdown...and these aeroplanes had rather "limited" production....