RV-10 Maintenance alert!

[Ivan Kristensen]

During regular maintenance I noticed that the flange, holding the 4" scat hose for the oil cooler, was cracking. The cracking had extended 3/4 of the way around and needed immediate attention. This obviously has potential serious consequence should it break off all together.

Now in defense of the original Vans part I had installed an "after market" butterfly valve to control the airflow from the cockpit. This obviously caused additional weight and stresses on this flange from engine vibration and is likely the reason that the weld of the flange cracked.

A better solution to this problem might be to mount the butterfly valve on the Oil cooler, this would isolate it from the engine vibrations.

The pictures below will tell the story and show the fix.

My long time friend and repeat RV offender Roy Pinner helped me with parts and tools for this repair. Thanks Roy! It was on my way back from his place, just before dark over central Florida, I snapped the picture below.

 

[Bill.Peyton]

Thanks Ivan. I will check it today

 

[GTWreck]

I had much the same thing and noticed it before my first flight. I too use the butterfly valve, but mine is mounted at the bottom (on the oil cooler bracket on the firewall). The 4" flange that I used which is mounted to the baffles had a couple spot welds around the perimeter. As I was triple checking that everything was good and tight, I managed to break on of the welds just by pulling on the scat tube.

My fix was very similar (small angle bracket screwed into the baffle and 4" flange).

 

[rleffler]

I recently did that check and didn't find anything, but my butterfly is mounted to the oil cooler.

Thanks for bring this to everyone's attention.

bob

 

[aerhed]

If I'm thinking right those are only tack welded in four places.

 

[gasman]

Looks like your scat is in contact with the motor mount causing vibration to transfer to the flange. I expect it to still have problems.

 

[g zero]

Alert

I think a good bead of Pro Seal would help prevent this , it would dampen some vibration .

 

[Ivan Kristensen]

Scst tubing

Looks like your scat is in contact with the motor mount causing vibration to transfer to the flange. I expect it to still have problems.

Yes the the Scat does come very close to the motor mount. As you can see I have a piece of hard plastic tubing RTV'ed to the mount to prevent chafing.

I regard what I did as a permanent fix but I think in a new installation I would place the butterfly valve on the oil cooler.

 

[Bill.Peyton]

Checked mine and all is good. I will make the bracket when I return.