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ACRO E-mail Archive Thread: Goldfish, aka The "Spider" (ZL axis does not a ...


Thread: Goldfish, aka The "Spider" (ZL axis does not a ...

Message: RE: Goldfish, aka The "Spider" (ZL axis does not apply)

Follow-Up To: ACRO Email list (for List Members only)

From: Mike Davis <davis at>

Date: Mon, 07 Apr 1997 16:32:54 UTC


whoa!  What I remember from judges school?
'zero-lift axis' only applies to verticals.
Yes your 45's need to be 45's and you need to adjust your
pitch accordingly.  This is no different than the jillion other
45 lines found in the blue book.

pretty tough to fly a 45 when generating 'zero lift'!

davis at

From:  administrator[SMTP:administrator at]
Sent:  Sunday, April 06, 1997 10:04 PM
To:  iac
Subject:  Goldfish, aka The "Spider"

I recent practice of the goldfish in the advanced sequence, and obvious
debate is cropping up regarding judgeing criterion.

In every airplane that I know, a constant 45 degree "zero lift axis"
before and after the ascending snap roll results in a markedly flatter
flight path after the snap roll.  So much speed is lost in the roll that
this is simply inevitable.

ALL of the critiquers I have been working with are calling "shallow
after" for this portion.  Adopting enough pitch to present something near   

to a continuous 45 degree flight path results in about a 70 degree pitch
angle.  Clearly, this is substantially at odds with the red book.

So, when we go to contests this year, are we going to get marked down for   

either "shallow after" or "steep after" (due to taking steep pitch to
give prettier presentation)?  Anybody else think this is going to give
lots of opportunity for random judging.

It might be worth saying that if we see a good looking flight path after
the snap, then we KNOW that the zero lift axis has gone steeper, yes?

What to do, what to do.

Don Peterson
Dallas, Tx.

PS:  I prefer watching a good flight path presentation, and have no
objection to flying it.  I also find it easier to judge, but the rule
book says this should not be so.


© Dr. Günther Eichhorn
Email Guenther Eichhorn