Main Landing Gear Geometry

[aeromatt]

Hi All,

I am looking for more information on main landing gear design, in particular, the practice of angling the mlg struts forward. I think it is common in many configurations but I am interested mostly in tricycle landing gear of small fighter jet size aircraft similar to F-5E.

Thanks,

Matt

 

[rb1957]

i'd look into an airframe design book ... raymer, torenbeek, maybe something specialised for landing gear design.

the point to angling fwd is to react the drag load along the LG strut ... look at a spitfire, Me109 LG

Quando Omni Flunkus Moritati

 

[aeromatt]

Thanks RB. I'll check those out. I know it's really common for tail draggers but seems to be a little less common for tricycle gears.

 

[rb1957]

which could be reasonable (i had to think twice about it) ... the normal landing attitude for a tail-dragger will be something close to horizontal, so the on-ground attitude will accentuate the fwd rake on the LG; for a tri-cycle arrangement the on-ground attitude is horizontal and tha landing attitude is nose up. i think there are other things in play as well ... better materials, maybe, but most gears (in the class of plane i think you're talking about) i think are designed to carry drag as bending in the main leg (as opposed to having a dedicated drag strut)

Quando Omni Flunkus Moritati

 

[aeromatt]

Raymer comments that ground handling is improved when the wheel moves aft as the strut is compressed (instead of forward which is what would happen if you had any angle in the opposite direction.)

In Torenbeek,section 10.5.3 and throughout the book he notes references like 10-1 and 10-13. In the reference section at the end, the various references are denoted with a "K" ie. K-1 to K-38. Does anyone know if the K and 10 are interchangeble so that Ref. 10-1 is actually K-1?

RB, Thanks for the suggestion and comments.

 

[rb1957]

i'll check tonight (if i remember) but maybe J-1 would be 10-1 ?

Quando Omni Flunkus Moritati

 

[WKTaylor]

aeromat... the (4) biggies on landing gear design/andalysis, that I am aware of [not including company design guides or SAE/MIL stndrds]...

Aircraft Landing Gear Design Principles and Practices
Author:
Currey, Norman S.
ISBN-13:
9780930403416
ISBN:
093040341X
Publisher: American Institute of Aeronautics & Astronautics

Landing Gear Design for Light Aircraft [Paperback]
Ladislao Pazmany

Landing Gear Design 1958
Hugh Graham Conway

http://books.google.com/books/about/Landing_gear_design.html?id=yXtTAAAAMAAJ

Chapman & Hall, 1958 - Airplanes - 342 pages

DAR Corp Roskam series Airplane Design books: Part IV: Layout Design of Landing Gear and Systems

https://shop.darcorp.com/index.php?route=product/product&product_id=59

Regards, Wil Taylor

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[rb1957]

there's a pic on Flight of a Bf109 ... makes you think that the easiest way to tuck a LG into the wing would have the wheel tangent to the front spar and the leg pick-up on the front spar, which naturally leads to a fwd sloping leg ... and puts the ground contact point ahead of the wing (which sounds like a good idea in a tail-dragger).

Quando Omni Flunkus Moritati

 

[drawoh]

rb1957,

The Bf-109 was known for many things, but good landing gear was not one of them. There must be a better example.

--
JHG

 

[rb1957]

geeze, it was just a pic i saw ...

Quando Omni Flunkus Moritati