Futaba radio question

[Troy A. Newman]

Negative expo on Futaba is softer neutral

.................
and Positive expo on JR is softer neutral

It takes about 20-30% expo just to get the surface to throw linear. The
reason is the servo is in a  rotational output vs. the pushrod which is a
linear output. If you use large servo arms and have the connection further
out on the servo wheel this gets minimized some...but you sacrifice
resolution of your servos because now you have to dial back you rates too
far to get the actual travel you want. I don't fly my D/R or my flying rates
back below about 75%. The reason is you sacrifice the precision of the
servo. I try to maximize my ATV values and keep the max out of the servo and
TX resolution as possible.

To this end you will need about 30% expo just to get a linear output to the
surface. I tend to run 40%-50% expo on Ailerons, about 40% expo on the
elevator and about 60-70% expo on the rudder in my normal flying rates.

I would caution against high expo values like 60-100% you will get a hump in
there and it will drive you nuts. Main thing you see is the roll rates don't
stay constant...They start slow speed up and then finish slow. The reason is
you are moving the stick so far before the surface responds.

Another note that may be significant to some. I fly one rate or Flight mode
all the time. I have a upline snap rate (aileron +10%, elevator +10%,
rudder -10% on the rates), this is only used for upline snaps where energy
management is critical. And I have a spin mode or condition where the
elevator rate is higher by 20-30% travel. This is until the break into the
spin...then the spin is done on the flying rate. The spin mode has more expo
on the elevator to give the same feel for flying as the normal flying rate.
All other rates stay the same in the spin mode.

 All snaps (save the uplines), rolling loops, circles and maneuvers are done
on the same rates. By the way these rate are all on the same switch and its
easy to prepare for the upline snap. or spin entry...

I think that if I could get used to the higher aileron rate I could fly the
upline snaps without a switch for these.

Hope this helps.

Troy Newman
----- Original Message ----- 
From: <tph1 at bellsouth.net>
To: <discussion at nsrca.org>
Sent: Friday, November 19, 2004 7:30 AM
Subject: Futaba radio question


> When trying to make a control serface less sensitive around center do you
add positive expo or negative expo?
> thanks, Tom
>
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