*LS*

Hello together,

I´m searching for pics of oleo struts because I want to design my own struts for my L-159. I tried to find some information about the functional principle by using google but I haven´t found any useful.

At the moment the L-159 has got normal struts but the damping is poor.
My problem is to design the struts as small as for example Skymaster. In my honest order they do not use springs?! Only oleo and compressed-air? I hope someone can give me a hint how these struts works. I would be glad if someone has got pics and maybe drawings?

Regards
Basti

Ps. Sorry because of all the mistakes, I´m not that good in English

digitech

My Feedback: (10)

Skymaster had federn drin , die sind auch mit oel und luft versorgt um die damfung was einfacher zu machen.
wen du was hilfe brauchst wir machen federbeine fuhr fast jeden sport jet.
zeig mal was bilder von deine beine mit die lange und rad.

DelGatoGrande

My Feedback: (23)

Hello Basti

L39 skymaster legs use springs too and there damping is also poor.

have you try any stronger springs? you can find some at www.mcmaster.com

in deferent dimentions and hardness.. take a look at the 9573K12 spring


Part Number: 9573K12


Type Die Springs
Material Steel
Steel Type Chrome-Silicon Steel
System of Measurement Inch
Wire Size .039" x .07"
Overall Length 1-1/2"
Ends Closed and Ground
Wire Type Round-Edge Flat Wire
Fits Hole Size 3/8"
Fits Rod Size 3/16"
Color Blue
Load 15 lbs.
Deflection Percentage at Load 25%

Deflection Percentage at Load 25%

Rate 42 lbs./inch

Specifications Met Not Rated

1Eye

My Feedback: (2)

Basti, here's a link to some information in English: [link=http://www.aoe.vt.edu/~mason/Mason_f/M96SC05.pdf]Oleo Strut Design[/link]. Your English is fine, my Deutsch sucks. [&o]

*LS*

Hello and thank you for your feedback!

My ambition is to produce struts by my self because then they fit best to the model. Also I love engineering.

I´ve tested some different springs in the main and front gear last year but the L-159 bounce on the grassfield if the landing speed is a little bit too high. Maybe the angle of attack on ground is also not correct and a bit too high but the damping itself is poor. The spring alone can not dissipate the kinetic energy.

The pdf-file from “1Eye” looks good but I´m furthermore interested in pictures of deconstructed oleo struts from other models.

How strong are your springs especially in L-39 struts? My spring deflection is on the maingear about 50 mm and the struts are approximately 20 – 22 mm compressed if the L-159 is standing on the ground with full fuel tanks.

Regards
Basti

Gordon W

This download has all you need.

http://www.rcmf.co.uk/4um/index.php?...pmod;dl=item17

You'll have to sign on with the parent forum to access the download.

Gordon

*LS*

Hello Gordon

I´ve downloaded your file and found this really interesting. It is the first undercarriage calculation for rc airplanes I have ever seen but there ist a little problem.
My struts are not that typical telescope struts. The damping characteristic is quite different. This ist also mentioned in the article.

Maybe another solution to dissipate the kinetic energy from the landing could be two springs with different spring rates. One soft spring to smooth out ruts and lumps in the runway while taxiing and a hard spring to smooth out landing shocks. I´ve heard that Jetlegend is using such a system in there L-39 main struts.

I´ve taken two pics of the struts which are mounted at the moment. Hopefully my first file upload will work[sm=confused_smile.gif]