Hi Silversurfer,
Good to hear from you and have your thoughts.
You sound like Sherlock Holmes, "it's elementary dear Watson!"
Good advice, if the plane has a problem without differential, try
using some.
Does not cost a penny and can do no harm.
If it helps what care the aerodynamics that did it?
That is of course, if all you wish is a correct flying airplane.
Be good,

Hal deBolt

pattern planes really don't need it....

Hi Doug,
In one sense you are correct, most planes do not need differential
Many of the superior pattern designs do well without it.
However, it is a competition craft where differential can pay off
best. it can garner points in the roll maneuvers by making axial
rolls true without input from the pilot.
Mystery is why one design does well without it and another good
design may require it desperately.
What would be interesting would be to conduct an investigation
to determine the cause for the need with one and not the other.
But a wonder is if the effort is worth while when the use solves
the problem neatly and requires little to try.
Good luck and be good,

Hal deBolt

and what about hovering?, if the dif is not set up right the plane wants to quit when you are trying to enter a torque roll... does the setup for torque rolling work for pattern maneuvers?? opinions?

There will be no yaw in a hover because there is no airflow other than prop wash, and even if there was your so busy with the balancing act you wouldn't notice it anyway.

I have to disagree because if you have the plane in a stable hover and want to start a TR having neutral ailerons is very important otherwise the plane will want to quit when you add ail