Composite landing gear

Discussion in 'Composites' started by hiryu, Jul 12, 2006.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Jul 12, 2006 #1

    hiryu

    hiryu

    hiryu

    Member

    Joined:
    Mar 28, 2006
    Messages:
    15
    Likes Received:
    0
    Is there anyone out there who would undertake to custom-make composite landing gear struts? Single-piece, inverted U-shape, same dimensions as Sonerai II, MTOW about 860 lb.
     
  2. Jul 12, 2006 #2

    wsimpso1

    wsimpso1

    wsimpso1

    Well-Known Member

    Joined:
    Oct 19, 2003
    Messages:
    5,674
    Likes Received:
    2,924
    Location:
    Saline Michigan
    I came to the conclusion that I would rather have steel legs on my design. Reasons were weight and drag. By the time I got the needed strength and energy absorption, they were heavier than steel, and much thicker too.

    Other reasons - They would be one big, thick layup, which makes its integrity tough to ensure, and there is the issue of having to build molds, etc.



    Billski
     
    Aviator168 likes this.
  3. Jul 13, 2006 #3

    Midniteoyl

    Midniteoyl

    Midniteoyl

    Well-Known Member

    Joined:
    Sep 4, 2003
    Messages:
    2,406
    Likes Received:
    500
    Location:
    Indiana
    From what I've seen, composite legs are not the way to go. By the time you make them stiff enough to actually hold up to the abuse of landings, they are not flexible enough to last long. The Express went to fiberglass legs for a breif time, then switched to aluminum. The new legs are much better than the glass, and increased the GTOW by 200lbs.
     
  4. Jul 13, 2006 #4

    hiryu

    hiryu

    hiryu

    Member

    Joined:
    Mar 28, 2006
    Messages:
    15
    Likes Received:
    0
    Thanks. This is helpful. However, Midniteoyl, did you mean the aluminum legs were 200 lb. heavier, or lighter than the composite?
     
  5. Jul 14, 2006 #5

    Midniteoyl

    Midniteoyl

    Midniteoyl

    Well-Known Member

    Joined:
    Sep 4, 2003
    Messages:
    2,406
    Likes Received:
    500
    Location:
    Indiana
    They weighed about the same, but were much stronger and allowed the GTOW to be increased by 200 lbs (3400 to 3600).

    Side bonus: the aluminum was thick enough to be drilled and used as a brake line.
     
  6. Sep 23, 2014 #6

    Domingo Cattoni

    Domingo Cattoni

    Domingo Cattoni

    New Member

    Joined:
    Sep 23, 2014
    Messages:
    1
    Likes Received:
    0
    Location:
    Buenos Aires Argentina
    Hi guy's, Mi name is Domingo, I'm from Argentina.

    I have a question for you, i would like to know with which material fabricated the land gear core. Some guy used a composite materials so called Bone, (but I don't know what is this) It can be?, some guys's use main gear strut.

    Thank for read my note.

    Pd: My English is very bad, I'm sorry.
     
  7. Sep 26, 2014 #7

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    mmmm I find it very hard to believe landing gear cant be built from a combination of glass and carbon fibre uni fibres and combined with shape should be used as the a way of increasing stiffness ,flexibility ,springiness or what's required , its also got memory that most metals don't have !!!
    I have recently seen a U shape as landing strut made solely 100% from unidirectional glass all going in one direction only and i hope Vinylester resin !!
    I honestly cannot believe the ignorance of whoever the builder was !! structures of such nature require a mixture of other types of glass with different orientationed fibres as well as the unidirectional glass to hold the whole structure together ! The simple excise of slightly twisting Uni fibres adds enormous strength and much more durability when using uni glass! if there's a collection of twisted fibres laid together then 50% needs to be twisted the opposite direction, but laid side by side with each other so they work together, one protecting the other.
    In the boating industry its not uncommon to lay 2 layers of uni fabrics one on top of the other but are set a 95 degrees and 85 degrees to the keel line so the layers of fibres hold each-other together
     
    Last edited: Sep 26, 2014
  8. Sep 26, 2014 #8

    cluttonfred

    cluttonfred

    cluttonfred

    Well-Known Member

    Joined:
    Feb 13, 2010
    Messages:
    6,350
    Likes Received:
    2,215
    Location:
    World traveler
    Aerowerx and Norman like this.
  9. Sep 26, 2014 #9

    kent Ashton

    kent Ashton

    kent Ashton

    Well-Known Member

    Joined:
    Aug 15, 2008
    Messages:
    714
    Likes Received:
    201
    Location:
    Concord, NC
    Very desperate & poor (or just hardheaded) people in the canard world have made their own composite gear hoops but most buy them from Featherlite who are probably not interested in a onesie project. You can buy the S-glass tapes from Aircraft Spruce. Build a mold, layup a thousand layers ;-) Some pics here
    Carbon Fiber Composites

    Interesting laminated wood gear in this thread
    http://www.homebuiltairplanes.com/forums/wood-construction/5032-laminated-wood-landing-gear.html

    I would try to adapt a gear from something: Sonex, Long-ez maybe?
     
  10. Sep 27, 2014 #10

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    wow !! after cruising this particular composite landing gear and seeing the wooden landing gear thread as well as carbon etc etc one glaring fact is the radiuses used ! it a well known fact that sharp radiuses fail quicker as many times the stress is imposed on a very small localised area ! I learned that many years ago when first started to get into composite work !! Looking at the French site they are using big radiuses and gentle curves over a much longer distance !! so the same bending loads are distributed over a much much longer bigger area !! The wooden beam that split and cracked was doomed before the glue had dried !! change the shape of the beam It would never have split or broken !! there was absolutely nothing wrong with the materials used or the workmanship its all in the design used and final shape that's the problem!!
    Laminating layers of wood or layers of unidirectional glass same principles apply !!
    Shape is the key that is not being looked seriously enough I feel after seeing and reading all through these threads be it wood or composites !
    Take a gentle curve and introduce a kink and that's your weak spot !! make the kink a smoother shape and a large proportion of the weakness has been eliminated !! Remember shape also makes things stronger as well !!!but can also be a weakness !! so you decide !!!
     
    Last edited: Sep 27, 2014
  11. Sep 27, 2014 #11

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    Just a quick note that could help and make people re-think !!
    I see most everyone loves to use woven glass !! In the boating industry woven glass of any thickness is slowly being phased out because it not as strong as you think it is ! PLUS the other down side is it uses more resin !!Its only a small amount but on a big job this all mounts up ! and if damaged I possible to simply peel off the under laying surface in big sheets as within its self its strong and flexile !! Better glasses are no woven as damaged areas are jus that small damaged areas not a whole area !!
    WOVEN GLASS also is not as ridged on a flat panel as a non woven glass !! I see the picture of the of the wooden landing gear that was cracked and split and see it as repaired with woven glass ! do you realize 50% of the fibres n that woven glass are doing almost nothing at all ??
    Orientation of the glass fibres in any and all things needs to be looked at very carefully if you want to get the maximum amount of strength for the least amount of materials used !
    The boating industry has been very slow to change its antiquated ways and rethink better materials and construction methods .
    Trying t re-educate older workers is almost impossible and i have found its better to start with some one that has no knowledge at all and no preconceived bad ideas of any sort !!!
     
    Last edited: Sep 27, 2014
  12. Sep 27, 2014 #12

    cheapracer

    cheapracer

    cheapracer

    Well-Known Member

    Joined:
    Sep 8, 2013
    Messages:
    5,049
    Likes Received:
    3,327
    Location:
    Australian
    Here's some details of my landing legs if anyone interested ...

    span; 1550mm 61"
    width; 100mm 4"
    thickness; 25mm 1"
    weight; 9.4 kgs 20lbs (unfinished)

    When I clean them up I will figure how many layers of what material then and post that info. There's at least 50 sets of these being used and for quite some time so well proven.



    landing gear 3.jpg
     

    Attached Files:

  13. Sep 27, 2014 #13

    tunnels

    tunnels

    tunnels

    Banned

    Joined:
    Sep 7, 2014
    Messages:
    559
    Likes Received:
    21
    Location:
    china is my home , place of work but was born in N
    In high stress places all those uni strands should have double bias mixed amongst it to actually hold all those layers of glass strands tightly together to stop spitting and fracturing !!! I see the radius is quite big and has no kinks so that's a huge plus !!
     
    cheapracer likes this.
  14. Oct 23, 2014 #14

    n89gf

    n89gf

    n89gf

    New Member

    Joined:
    Oct 23, 2014
    Messages:
    2
    Likes Received:
    0
    Location:
    Lafayette Louisiana
    My longezy main gear strut requires replacement due to hot brake damage. where can I get a replacement and what is the best way to do it. Does anyone have a new or used one?
     
  15. Oct 23, 2014 #15

    harrisonaero

    harrisonaero

    harrisonaero

    Well-Known Member

    Joined:
    Oct 31, 2009
    Messages:
    539
    Likes Received:
    265
    Location:
    Coeur d'Alene, ID
    Found these links to Featherlite, hope it helps...
    [TABLE="width: 100%"]

    [TD="width: 20%"]Featherlite[/TD]
    No web site, but you can email them at fthrlite@pacific.net
    [/TABLE]
    FeatherLite - Main and Nose gear struts. 1327 S. State St., Ukiah, CA 95482. (707) 462-2939
     
  16. Oct 24, 2014 #16

    Hugh Lorimer

    Hugh Lorimer

    Hugh Lorimer

    Well-Known Member

    Joined:
    Feb 14, 2008
    Messages:
    298
    Likes Received:
    99
    Location:
    Stair, Ayrshire, Scotland.
    No sharp or tight corners , make moulding block, cover with cling film, lay up strips of cloth, lay in contoured wood strips (core) lay up more glass strips let set , remove from block, trim then bind with more glass tape. trim and finish make axle brackets and bolt them on , fill brackets with glass/epoxy matrix, drill axle holes.............
    Hughie.
     

    Attached Files:

    tunnels, cheapracer and danmoser like this.
  17. Jun 10, 2019 #17

    ULF

    ULF

    ULF

    Well-Known Member

    Joined:
    Oct 24, 2015
    Messages:
    58
    Likes Received:
    19
    Location:
    Vienna , Austria
    Best used ash wood. Ash (german "Esche") is used for the bow and arrow, because its flexibel properties. Has to be brought in shape though befor laminating, like hybernating in wet condition, laminated together from single thin boards. that core then is used as the core material.
     
  18. Jun 11, 2019 #18

    vhhjr

    vhhjr

    vhhjr

    Active Member

    Joined:
    Jun 29, 2003
    Messages:
    31
    Likes Received:
    23
    A few years ago we built and tested some laminated landing gear legs for the Facetmobile project. A half scale gear was built and loaded with 1/8 the Facetmobile gross then dropped from various heights. We broke several gear legs in the process and decided that hickory was the best. The legs were laminated from .100 inch thick layers with T100 epoxy and glass tow between layers. A two piece press with a length of fire hose converted into a pneumatic bladder was used to form the gear legs. The Ash, Hickory and Hemlock samples were water soaked and dried in a form to give them the proper shape before gluing them up in the press. The half scale Hickory gear survived being dropped from up to 18 inches loaded with over 100 lbs. We found that a gear shape with no sharp corners and a gentle curve was the best. The straight leg versions all failed at the bend or where the gear exited the gear mounting structure.

    A full size leg press was made and a photo is attached. In the end the Facetmobile builders decided to go with a tapered steel rod gear. The facetmobile will fly later this year and we'll see how the gear works. I have a laminated one hanging from the ceiling of my hangar should it be needed.
     

    Attached Files:

    pictsidhe likes this.
  19. Jul 12, 2019 #19

    meglin1

    meglin1

    meglin1

    Well-Known Member

    Joined:
    Nov 12, 2015
    Messages:
    222
    Likes Received:
    36
    Location:
    Ukraine
    We have been doing here are the springs chassis. They are put on single, double and triple planes, gyroplanes, trikes and paragliders. Takeoff weight from 300 to 600 kg. Spring weighs up to 11 kg. Material - fiberglass.
     

    Attached Files:

  20. Jul 23, 2019 #20

    opcod

    opcod

    opcod

    Active Member

    Joined:
    Aug 28, 2010
    Messages:
    27
    Likes Received:
    0
    Location:
    Canada
    Lots of plane do used composite leg.. Yes the eze plane with the diy... but all the Pipistrel... all in composite. So doing an alu thing is of no used. But for bush plane, yes.
     

Share This Page

arrow_white