From: Sky2high@aol.com
Message-ID: <29.1fb9f7b6.29523ae2@aol.com>
Date: Wed, 19 Dec 2001 13:48:02 EST
Subject: Re: Lancair 320 unnatural dragging to the left
To: lancair.list@olsusa.com
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Rob and Per,

The prop disc better not be perpendicular to the centerline.  If I remember 
correctly, the engine is canted to the right 1.5 degrees.  This can also be 
noted by assembling your cowling off the airplane, setting the aft side on a 
level surface and noting the side to side slope of the front of the cowling 
flange.

The variation of the engine from the horizontal should have little or no 
affect on yaw, but on speed (drag).  After using soft engine vibration 
isolators, my engine sagged as much as 3/4 inch from the top of the cowling 
in flight (measured the bug splatters on the cowl flange).  I have shimmed 
the lower mounts 1/4 inch to now match the cowling, which was built to specs 
with the engine mounted.  I believe the engine also is to have a slight 
upward cant.

The ball is still the best tool (If calibrated to the aircraft references) to 
straighten out rigging problems.  Hands off level flight with the ball 
centered after trimming all control surfaces is the real measure.  Then use 
your eyes, a mirror and/or formation flight to identify extraordinary 
displacements of the control surfaces i.e. rudder and elevator horns 
displaced far from neutral and ailerons not meeting the wingtip.  Remember to 
record the GC and side to side loading imbalances.

I don't know about other planes, but about 50 percent (mine included) of a 
visual survey of 320s at Oshkoosh have a twist at the top of the vertical 
stab.  The moldings also seem to have the trailing edge of the inboard 
fuselage flap fairing 1/2 inch different horizontally from side to side.  
Also, I don't know about the fast builds, but slow build vertical stab rib 
plans were not even close to the moldings -- It is possible to build a 
vertical lifting wing if the moldings were relied on.

In that light, in my airplane, high power climbs and low power operation 
require right rudder (AOA is "high") and cruise requires some left rudder to 
keep the ball centered.

Scott Krueger
N92EX

PS.  I have a "heavy" left wing, but this was mainly fixed by adjusting the 
flap rigging and, since I was in "primer", sanded the micro fitted final 
fairing.  The rest was fixed by carrying a compatible enthusiast in the right 
seat, unbalancing the fuel load or trimming the aileron.
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