I use a Futaba 9CH with triple rate. I believe the ability to change rates
while in-flight is very useful especially in conjunction with exponential.
Though there are times when the full throw specified for a given model is
very necessary (recovering from mistakes, pop-offs, broken lines, crosswind
landings, ground effect on landing and many more), in most cases, without a
very light thumb, it's to much for general thermal flying. Dual rate (in my
case triple rate) in conjunction with exponential, when set up correctly,
can help to solves this problem.
The following is an example of a standard 6 servo set up that I use on my
Open Class Sailplanes. Though this example will show use of triple rate you
can set up almost the same with dual rate. You must be sure that
exponential and triple/dual rate are actuated by the same switch.
TRIPLE/DUAL RATE EXPONENTIAL USE
First position on triple or dual rate/exponential switch:
Launch, Land and Turbulent air.
AILE ----- 100% rt. -50 % lt. -50 %
ELE ----- 100 % up -25 % down -35 %
RUD ----- 100 % rt. -45 % lt. -45 %
Second position on triple or dual rate/exponential switch: Most
flight conditions.
AILE ----- 70% rt. -0 % lt. -0 %
ELE ----- 85 % up -15 % down -25 %
RUD ----- 80 % rt. -25 % lt. -25 %
Third position on triple or dual rate/exponential switch:
Light thermal conditions.
AILE ----- 55% rt. -20 % lt. -20 %
ELE ----- 75 % up -10 % down -20 %
RUD ----- 65 % rt. -10 % lt. -10 %
As you can see the exponential setting is reduced as the throw is reduce.
In this way you still retain good response. When the exponential cut-off
point is reached (about 1/2 stick on most transmitters) full response is
restored.
My conclusion:
The use of Triple/Dual rate in conjunction with Exponential helps to
overcome many of the problems that result from to much or to little control
throw for a specific situation. I believe if it used correctly it can help
many improve their flying skills.
Just what I think.
Maurice
----- Original Message -----
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Tuesday, September 07, 2004 9:30 AM
Subject: [RCSE] Dual Rate / Exponential
Got a bit of a debate going locally on the merits of dual rate and
exponential. Some folks like it, some don't. Any comments from the exchange
on this one? We were thinking about doing an overview article for RCSD but
the opinions are mixed and strong. Looking for any feedback from users or
non-users. If the article is written, I'll provide attribution as
appropriate.
For the record, I use negative exponential for ailerons on launch and when
working real light thermals. My normal control authority is fast so this
helps with over controlling in touchy situations. I'm told this is wimping
out but it seems to work for me.
On-line or off-line comments welcome.
- Dave R
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