Thanks for the illuminating reply.  We are about to "finish fill” so now would 
be a good time to add it if we are going to do it.  

My son’s KR is an early KR2s with the stretch and slightly larger tail but RAF 
airfoil.  We are certainly going to add stall fences.


> On May 28, 2018, at 8:10 PM, wrote:
> Owen and all,
> Yes, the ventral fin was installed to deal with prop wash and torque.  
> Studying what was available on the NACA pages through NASA gave me several 
> ideas, extending the vertical stab, increasing rudder size, or adding a 
> ventral fin.
> The ventral fin is slightly forward of the vertical tail to better counter 
> the corkscrew effect of propwash and allow the fin to be taller.  It works 
> extremely well.  Golaith needs much less rudder in steep climbs, and cruise 
> is straight as an arrow, regardless MAP setting.  It also has a positive 
> effect on approaches to stall.  On the downside, fast descents/low power 
> descents need rudder in the opposite direction, more so than before.
> I suspect the fin would have a positive impact on spin resistance based on 
> the plane's new approach to stall characteristics, BUT THE KR IS PROHIBITED 
> FROM SPINS anyway.  No plan to test this theory out.
> If I were to do it again, I would probably angle the fin 1-2 degrees LE 
> right.  That said, I love what is has done for the handling of the plane.
> iMs,
> Zip
> -----Original Message-----
> From: "svd via KRnet" <>
> Sent: Monday, May 28, 2018 5:52pm
> To: "" <>
> Cc: "svd" <>
> Subject: KR> Ventral fin on Goliath
> Dear <>,
> I couldn’t review old emails from the archives - so I thought I just ask.
> How does the ventral fin on Goliath work? Did you add it for directional 
> stability or spin recovery?
> Cheers,
> Owen

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