Lycoming 4 cylinder models have bad vibration characteristics. Especially the IO 360 200 hp model which had an AD issued for the cs oil delivery line from the pump to the nose end of the engine. Those fittings had to be changed out to black (steel) fittings. And the delivery pipe reinforced as well with a new cushioned mount. And the end at the prop governor also changed out. Don't ask how I know.
Marc Wiese
>
> From: Lehanover@aol.com
> Date: 2005/03/29 Tue PM 04:26:08 GMT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: AN fittings..
>
> In a message dated 3/29/2005 10:14:16 AM Central Standard Time,
> Dastaten@earthlink.net writes:
>
> << Considering I am going to be sending the oil  into a fitting that is
>  connected to an aluminum bypass block on the pedestal, in OUR (rotary)  
>  situations is this a critical issue? And what is/was the rationale for
>  not using AL fittings on the Lyc's? Dissimilar metals? Heat expansion
>  stresses? Fatigue?
>  
>  Dave >>
>
> Fatigue.
>
> Aluminum has a short fatigue life.
>
> The engine is moving around on the mount all of the time. All hose runs to
> the engine should have a curve and some slack in them to account for this
> movement. The hose is clamped away from the engine with Adel or as part of another
> hose end as in a bulkhead fitter or similar. Refer to your hose catalogue for
> acceptable methods of installation.
>
> Lynn E. Hanover
>
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