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Question on for example why 737's doesnt have wheelbaydoors...???

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  • Question on for example why 737's doesnt have wheelbaydoors...???

    *Please read thread title.*


    Thanks.

    [photoid=5726220]


    Thank you in advance.


    Cheers,
    Jesse Nielsen
    Jesse Nielsen / Cimber Air F/A


    Offers Dreams and Experiences To People Around The World..



    If I'll Be Flying The Long Distance, ANA Would Be My First Choice....








  • #2
    Jesse,

    Basically having no gear doors reduces complexity and saves weight.

    Landing gear doors require microswitches and a hydraulic or electric means of motion, all of which add a layer of complexity to the aircraft, not to mention weight. Quite simply, if you can do the job just as well without the doors, why put them in?

    The B737 isn't the only aircraft like this though, some of the RJ types as well as some bizjets also use the same design philosophy...

    Here's a slightly different perspective of a B737 wheel well -



    Hope that helps

    Dale
    Last edited by G-DALE; 2006-05-11, 22:47. Reason: Resized wheel well image.

    Comment


    • #3
      Wouldnt want the wheels to explode..

      Originally posted by G-DALE
      Basically having no gear doors reduces complexity and saves weight.
      Actually the weight and all that wasnt really on my mind.
      Originally posted by G-DALE
      Landing gear doors require microswitches and a hydraulic or electric means of motion, all of which add a layer of complexity to the aircraft, not to mention weight. Quite simply, if you can do the job just as well without the doors, why put them in?
      What I was thinking about is the wheels, having the wheels being exposed to the thin air, I mean how far in altitude before it gets too dangerous to have the wheels "outside".. The types in other planes *or basically those with doors. Arent they pressurized to protect the wheels... Oh wait... They are pressurized right.?. No ?

      Originally posted by G-DALE
      The 737 isn't the only aircraft like this though, some of the RJ types as well as some bizjets also use the same design philosophy...
      I knew the other types. Thats why I put the *for example there in the thread title. Thanks so far Dale !


      Cheers,
      Jesse Nielsen
      Jesse Nielsen / Cimber Air F/A


      Offers Dreams and Experiences To People Around The World..



      If I'll Be Flying The Long Distance, ANA Would Be My First Choice....







      Comment


      • #4
        As best I recall, the wheel wells are not pressurized, even with doors.
        So many planes, so little time....

        Comment


        • #5
          Originally posted by JessNil
          What I was thinking about is the wheels, having the wheels being exposed to the thin air, I mean how far in altitude before it gets too dangerous to have the wheels "outside"..
          The tires are filled with nitrogen.. Unlike regular air, it won't turn to a liquid or freeze until the tempurature is some where around -170C or less. N2 also won't cause oxidation or rusting.

          For more info, you can hit up the following:

          http://www.airmichelin.com
          and
          http://www.goodyearaviation.com

          Comment


          • #6
            Yeah I know.. ..My post is not contributing with anything at all. .lol.

            *Jesse. Thats pretty nice questions and thinking you got there...

            I thought you were in the airline business. You could have asked your colleagues instead but you stated them here. How sweet
            Inactive from May 1 2009.

            Comment


            • #7
              As I understand it the tyres are inflated to a pressure equivalent to several atmospheres, so the reduction in outside air pressure at high altitude doesn't actually make that much difference. On the 737 (as well as other types that do not have wheelbay doors) the mainwheels are designed to fit flush with the fuselage surface and the outer wheel also has a smooth hub cover to minimise drag.


              Comment


              • #8
                everything mentioned sounds good, only other reasons I can think are a) putting another door type on there makes the system more complicated, requiring more moving parts, more things that need to be fixed, and b) having an exposed wheel helps with brake cooling. Brakes on aircraft get extremely hot, even during taxi the temperature can go up pretty high. Having overheated brakes can cause the air in the tire to expand and the tires can blow. The open gear will help cool the brakes so this doesn't happen, and if it did happen, because its not enclused in the gear wells, if something were to explode, it would do less damage to the aircraft.

                Comment


                • #9
                  Brakes are designed to be operated hot... the hotter the better (up to a point)...

                  And brakes shouldnt be getting used at all on a takeoff roll and so you wont get explosions in the gear bay due to hot brakes...

                  The only time you get hot brakes is on landing and obviously, the landing gear is extended for THAT occourance...

                  I'd put money that a wheel explosion IN the gear bay would puncture the pressure hull, hydraulic lines, fuel lines and could even bring an aircraft down... gear doors or not...

                  Gear Doors aid aerodynamic efficiency but if they're damaged and need to be removed (Yes, some aircraft can fly with certain doors removed) then the aircraft becomes as aerodynamic as a breeze block and the cost of operating goes through the roof.

                  Not having doors means that if you dont have them installed, they cant go wrong...!

                  Comment


                  • #10
                    mmmkay, so planes never abort takeoffs, get the problem resolved, then head out. Nor do they use the brakes on taxi.

                    Comment


                    • #11
                      Originally posted by Myriad
                      Brakes are designed to be operated hot... the hotter the better (up to a point)...
                      That really only applies to carbon brakes, a concept not around when the 737 was developed.

                      Comment


                      • #12
                        ^^These were never applied to the B737's NG's ....?
                        Inactive from May 1 2009.

                        Comment


                        • #13
                          mmmkay, so planes never abort takeoffs, get the problem resolved, then head out. Nor do they use the brakes on taxi.
                          The aborted takeoff scenario is the only time brakes will get "warm" before takeoff, if the brakes got so hot the tyres were to explode, it would likely happen on the taxi back to takeoff or on the takeoff roll itself...

                          And as for brakes being used on taxi, if you get a hot brake unit from simply braking from taxi speed... there is something seriously wrong with the unit.

                          That really only applies to carbon brakes, a concept not around when the 737 was developed.
                          That is true, Steel brakes are not reliant on temperature anywhere near as much as Carbon brakes. However i'm fairly sure that modern B737's have Carbon Brakes.

                          Comment


                          • #14
                            After an RTO, you consult brake energy and cooling tables before taking off again. That is if the aircraft isn't equipped with brake temp monitoring.

                            We have to wait 10 minutes after landing before the next takeoff is attempted with the Dash. With an RTO, we have to consult the tables.
                            Bite me Airways.....

                            Comment


                            • #15
                              Gear bays with doors would make the aircraft more efficent and faster, not only more aerodynamic. But look at the nose gear doors on the 73',notice there in one peice? less mechanical moving parts and less to go wrong, most likly the reason why the 737 has no operable main gear doors, plus monies, cheaper to operate this in the long run.
                              -Kevin

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