Note: The plans do not call for rivets above the middle rudder hinge bracket.
Added four rivets above this bracket..Page 6-3

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Modification:  Added 2 rivets per spar cap above middle rudder hinge bracket. Page 6-3 of plans. Even with the taper, the minimum rivet pitch of 3D or 3 diameters of the rivet being driven is met. Edge distance of minimum 2D and maximum of 4D is also available.

Rivets used: AN470AD4-5

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Vans Comments: Vans answer; " I guess they are. not needed" but they also said it can't hurt to add a couple.