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ACRO E-mail Archive Thread: Pitts S1S roll rate/Falcon ailerons

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ACRO E-mail Archive Thread: Pitts S1S roll rate/Falcon ailerons


Thread: Pitts S1S roll rate/Falcon ailerons

Message: Pitts S1S roll rate/Falcon ailerons

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From: Finn Jensen <finnjensen at>

Date: Thu, 13 Mar 1997 23:40:33 UTC


On the issue of aileron spades VS no aileron spades on the the Falcon
ailerons, I would really question the safety of not installing some form of
aileron counterbalance.  Especially with plywood covered ailerons.

I don't know how critical it is for flutter avoidance to achieve neutral
aileron balance on the Pitts S1S, but I guess that I leaned to the
conservative side when I built my Falcon wings.  I have never heard of
aileron flutter on a Pitts S1S, but the standard Pitts ailerons are
considerably smaller and lighter than the larger and heavier modified
ailerons that many of us now use.

I originally covered my ailerons in plywood, which I later removed.  The
small amount of aileron weight required considerable counterbalance.  In
addition to adding to the total airplane weight, the location of that
weight had the negative effect of adding to roll inertia.

The ailerons are now fabric covered.  I replaced the standard aluminum
spades with steel blades to achieve neutral balance, a difference of about
one pound per spade.

I have flutter tested to beyond Vne with no issue.  Would the ailerons
flutter without counterweights?  Probably not, but I am not going to be the
one to find out.

Finn Jensen


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