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shock struts

Posted: Tue Feb 04, 2020 3:52 pm
by 173rd.abn.bde2426
I'd like to replace the bungee arrangement on the shock struts on my Pietenpol with springs. Any ideas ?

Re: shock struts

Posted: Tue Feb 04, 2020 7:36 pm
by Earl Brown
this article has some good info- a good place to start if you want to change over to springs.

https://flycorvair.net/2012/10/27/new-d ... a-m-4-p-m/

Re: shock struts

Posted: Thu Feb 06, 2020 12:16 pm
by 173rd.abn.bde2426
Thanks foe some really great info. My one question is that my struts as drawn, show them attaching to the bottom V of the gear and to the front mounting plate in one straight shot. Forgive my ignorance but would your springs work on that arrangement? My welding skills are non existent so I would sleep on the sidewalk to be first in line, should you decide to make a kit for these springs. Thanks for your help ( great pictures ).
Bill Keener
Westlake Ohio

Re: shock struts

Posted: Thu Feb 06, 2020 9:53 pm
by taildrags
Bill: are your struts set up sort of like some variation of this?
gear.jpg
Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

Re: shock struts

Posted: Thu Feb 06, 2020 9:55 pm
by taildrags
If so, the "spring in a can" setup should work just fine. There is a bit of a delicate geometry where the two shock struts cross each other, but you should be able to work that out by adjusting the mounting point of one or the other of the struts up at the top end.

-Oscar

Re: shock struts

Posted: Fri Feb 07, 2020 7:47 am
by Earl Brown
if your landing gear is built to plans, then, it could work. this plane had bungees and got changed over to springs.
These are external springs- the spring in a can version is a bit larger so clearance might become an issue.
These are a couple of images on how to make the external spring type gear.

Earl
Springs.jpg
Spring_Gear_104.jpg
Xspring.jpg

Re: shock struts

Posted: Tue Feb 25, 2020 8:16 pm
by at7000ft
Built a cub style gear for my Piet using the GN-1 plans with the front/back attachment points the same as the Piet plans. Used die springs rather than bungie cords also. Was advised to move the front axle position forward 3-4" (especially with brakes) and glad I did, have had no problems with the gear after 6 years of flying. As WW has brought up many times the last Piets Bernard built had the front axle moved all the way up to the wing leading edge. Also found that Bernard's spring-in-a-can design is a better way to go as WW describes here:

https://flycorvair.net/2012/10/27/new-d ... a-m-4-p-m/


Image

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FYI: the die springs specified in the attached plans are a little weak, ended up using these from ACS -

https://www.aircraftspruce.com/catalog/ ... kkey=68598