Baffle cracks - odd location

[seattleworm]

While the upper cowling is off for other task, I decided to inspect the oil cooler area for sign of cracks. I did find cracks, but not at the common locations reported in the forum. You can see the cracks in the picture below. For now, I just stop drilled the crack, hope it will stop right there. Has anyone seen cracks in this odd location? I don't quite understand why crack there, since the fwd flange is not connected to anything rigid, just the baffle seal material. My RV-7 got about 70 hrs on it.

[Richard Connell]

Check the inside of the cowl for damage at that location.
I had similar cracking in that area due to the engine shaking and the baffle edges (or the rubber squeezed between the baffling and cowl) touching the inside of the cowl.
Cheers
Richard

[seattleworm]

Thanks, Richard! I did check the upper cowl for any damage, but found none, not even the sign of excessive rubbing. It could be the rubber squeezed in between so tight that it won't rub, but will transfer compressive load when engine vibrates. I will trim the corner a bit to see if it will help. Hope the crack will stop where it is.

[petersb]

Originally Posted by seattleworm

While the upper cowling is off for other task, I decided to inspect the oil cooler area for sign of cracks. I did find cracks, but not at the common locations reported in the forum. You can see the cracks in the picture below. For now, I just stop drilled the crack, hope it will stop right there. Has anyone seen cracks in this odd location? I don't quite understand why crack there, since the fwd flange is not connected to anything rigid, just the baffle seal material. My RV-7 got about 70 hrs on it.

Mine cracked exactly the same at about 30 hrs. I stop drilled and it has not moved in an additional 120 hours .

Peter

[BillL]

Thanks for this post, it is timely for me. I am entangled with baffles and plenum cover.

OK - Comment - I (stayed at a holiday inn . . . .) studied this and read every post on baffles. It seems that the oil cooler wags (pivots) about the left side where you reinforced. This crack would seem to confirm that it has become the stiffest link to resist that movement. If you look at other posts on cracking you see others that have installed a brace from the right side of the cooler back to the engine case for discouraging that movement.

This would indicate that the brace or some other "design change" might be needed to completely address the baffle cracking issue. I was hoping that the plenum cover might provide sufficient stiffness (and strength) to delete the brace.

Edit -apologies, I just saw the brace in the picture.

[RVG8tor]

I had #4 baffle cracks at about 50 hours as well as the crack like you have on the upper brace.

I redid the#4 baffle with re-enforcement and put in a new brace. The brace still cracked in short order. I stop drilled the crack and it has moved no further. The #4 baffle is still holding up total hours almost 300 now.

Cheers

[Geico266]

I would repair that spot by adding a doubler and riviting to the existing baffel. Obviously, it is not strong enough for the vibration in that area. Pulled rivets would be fine, IMHO, but ask your A&P.

I agree, put a doubler on it.

[Greg Arehart]

Been there, seen that, done the repair. Not particularly uncommon.

Greg

[R. Daniels]

That's a common area to have crack. Grab the cooler and tug on it hard. You should be yanking the plane around. If the baffling flexes at all it needs reinforcing or its guaranteed to crack.