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PostPosted: Tue Jan 22, 2008 11:24 am
by russell
Being things are sorta slow here on the forum, I thought it is a good time to show some more of my ignorance. It's common knowledge that when larger engines are installed the d-cell skin should go from .016 to .020. If I were to go to larger engines I would difinitely do this, but only because I am going with the masses, and all the while do not know exactly why it is required. What sort of stress is imparted to the wing and where and what is the manner of failure/deformation (putting aside a possible crash)?

Russell

PostPosted: Tue Jan 22, 2008 11:32 pm
by Shannon
Tech Update 6.7
http://www.lazair.com/tech.htm#1.1

Accordingly smart people put additional .020 doublers (from the root to just past the engine mounts) on Series III's when upgrading to JPX's from 185's. When this and some other modifications are made to a Series III you get wings close in strength to the Elite and Lazair II.

The JPX engine conversion kit instructions give a brief statement as to why wing upgrades are needed when swapping from 185's to JPX's.

Quote: "Components are provided to increase torsional and compressive strength of the D-cell to withstand the increased g-loading and torque pulses from the larger engine."

PostPosted: Wed Jan 23, 2008 8:11 am
by russell
Thanks Shannon, I was expecting you to respond with the answer. I have all the tech bulletins from when I assembled the plane but haven't looked at them since. Think I need to reread them. "slight buckle just inboard of the Nacelle", that statement along with your comments pretty much satisfies my curiousity.

Thanks