VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.

  #1  
Old 03-16-2005, 11:30 AM
parashak parashak is offline
 
Join Date: Jan 2005
Location: Hixson, TN
Posts: 56
Default Trim sensing?

NewB question here. I haven't had the experience of flying with an autopilot, so I don't know what this term means or implies.

Ref:
http://www.trioavionics.com/alt_hold.htm

In an autopilot, does trim sensing determine where you should put the trim to lessen the forces on the autopilot or does it sense when the trim is adjusted and correct for it before sensing the altitude deviation?

Is this an important feature? In what types of flying is it used?

Hope someone can clear this up for me. I am anxious to move up to a more capable plane, thanks to being able to build.

Regards, Paul
__________________
Paul Parashak
Nuclear Power Plant Operator
Retired Submarine Officer
Hixson, TN
RV-8A #82143
wing kit

"Reason holds the helm, but passions are the gales." - John Adams
Reply With Quote
  #2  
Old 03-16-2005, 01:01 PM
Sam Buchanan's Avatar
Sam Buchanan Sam Buchanan is offline
been here awhile
 
Join Date: Dec 2004
Location: North Alabama
Posts: 4,354
Default trim sensing feature

Quote:
In an autopilot, does trim sensing determine where you should put the trim to lessen the forces on the autopilot or does it sense when the trim is adjusted and correct for it before sensing the altitude deviation?
It is my understanding that trim sensing provides an indication that the autopilot is having to continuously work against an out-of-trim condition. It appears the Trio Altitude Hold will annunciate the need to adjust trim.

This is a nice feature, especially if it is included at no additional cost as it is in the Trio unit, but after flying the TruTrak AlTrak device for many hours I have not found trim sensing to be an essential feature. In my experience an RV will go significantly out of pitch trim only after two+ hours of flight. During most flights I find a need to change altitudes more often than that and the AlTrak and trim gets reset with each change. I always carefully trim the plane before engaging the AlTrak.

If the altitude hold is disengaged with the plane out of trim, there will be a sudden pitch excursion if you aren't holding the stick, but this motion will be quite small in most cases if the plane was trimmed properly before the altitude hold was engaged.

I don't see inclusion or exclusion of trim sensing as a deal breaker either way. If it is included, enjoy it; if not, don't worry about it.

Sam Buchanan (RV-6, 640 hrs)
http://thervjournal.com
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:30 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.