RV-14 Baffle Seals, Seal Overlap and AAPQ-4-3 rivets

[Meat]

Hi All,

Getting ready to rivet the rubber seals to the baffles. I had a few questions:

1. I'm guessing there's a reason Van's directs that AAQP-4-3 rivets be used for this on page 47-03. Is it the all-aluminum construction and the fact you're riveting rubber? Anyone know why LP4-3's can't be used instead? I ask because Van's shipped me the wrong rivet type for the AAQP-4-3. I need to reorder them but have lots of LP4-3 rivets.

2. I have significant overlap of all my seals. Is this normal/desirable? Van's seal schematic on page 47-23 shows V-shaped spaces between each seal junction and no overlap. No guidance is given nor is trimming directed in the plans.

3. What about the seal junctions at the aft left and right corners and overlap there? Should they be trimmed? I'm not sure how well they would seal in their untrimmed state against the upper cowling. Seems like they would bunch up vs lie flat against the cowling that way.


Thanks for your time, advice and experience.

Cheers,
Scott

 

[Jetmart]

No trimming required. Also unless they have changed the plans there are two pieces of the baffling material that are mislabeled. The pieces are on the sides and left is right and right is left. Drove me crazy until I figured it out.

 

[Desert Rat]

Yes, the seals should overlap a bit. The goal is to force cooling air to travel down between the cooling fins and not be able to shortcut through some gap or crevice.

Make sure that during installation you have the overlaps situated in such a way that air rushing aft from the cowl inlet is forcing the baffle rubbers flatter, not getting under the edges and lifting them up. Think of it sort of how shingle on your house overlap so that water doesn't leak in.

Regarding which rivet to use; without looking, doesn't an LP4 have a steel mandrel? Soft aluminum rivets might pull easier without damaging the rubber material and they will definitely be easier to drill out when the time comes to replace the baffle rubbers.

 

[DanH]

Depends on how air tight you want it to be. Every overlap is a slot leak about an inch long and the thickness of one seal.