Dudley Henriques wrote:
"Don McIntyre" wrote in message
oups.com...

Dudley,
I don't quite understand how the fuel tank installation relates to
the dorsal fairing. Wasn't the fuel tank related to the "ass-heavy" CG
on the B-model (or did that also apply to the D)? The airflow off the
canopy makes a lot more sense to me.
I'm not trying to pick nits here, just curiousity has reared it's
ugly head. 8-)


I wouldn't disagree with this . Just mentioned it because it was a NA
engineer who threw it out there to us at one time.
In my opinion it was the canopy change that necessitated the need for
the dorsal extension. I remember questioning him at the time as well.

It sort of makes sense. The "ass-heavy" rear fuel tank take away
stability, the dorsal fairing contributes to stability. The bubble
canopy upset the airflow behind it and in front of the fin, the
dorsal fairing may have improved this.

So the question is whether the dorsal fairing was added for the first
reason, the second, or both. The airplane may be too old a design to
get a definitive answer, but I wouldn't be surprised if they added
the fairing for both reasons.