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  #1  
Old 05-16-2018, 08:26 PM
Champ's Avatar
Champ Champ is offline
 
Join Date: Apr 2012
Location: Kingsville, Ontario, Canada
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Default Take Off Trim?

Wonder what others do with elevator trim setting on take off? I generally take off with no flap and with trim left where it was on last final. With this it seems to fly off when ready and only slight back pressure on the stick and no trim change on climb out. This is when solo and although my battery is in the back and a CS prop I still consider it nose heavy. Also - would you change take off trim with different flap settings and c of gs?
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Dennis Enns
Kingsville, ON
Bellanca Champ 7ACA since 1986, restored 1990.
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  #2  
Old 05-16-2018, 08:54 PM
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Veetail88 Veetail88 is offline
 
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Location: Hales Corners, WI
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Maybe sloppy on my part, but I never really think about. With the trim on a hat switch on top of the stick, I just adjust the trim when the airplane starts flying. Some times its pretty far off, especially if the last time I landed was with a passenger, but the stick pressure is always quite manageable.
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  #3  
Old 05-17-2018, 12:31 AM
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KRviator KRviator is offline
 
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Location: Sydney, Aust.
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Default

Quote:
Originally Posted by Champ View Post
Wonder what others do with elevator trim setting on take off? I generally take off with no flap and with trim left where it was on last final.
I routinely use partial flap for takeoff, but for trim, I do the same and leave it on the 'landing' setting.. Even though I have the trim position showing on SkyView, I don't bother with it until I am established in the climb. Stick forces, even with what I would call quite out of trim, have always been very easily manageable.
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  #4  
Old 05-17-2018, 07:05 AM
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AndyRV7 AndyRV7 is offline
 
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Location: Hudson County, NJ
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Default

Landing setting as well. I just can't turn my head enough to see the trim in my 7. Seems to work. Stick back until full power then let the tail come up, or ease it up.
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  #5  
Old 05-17-2018, 07:30 AM
n816kc n816kc is offline
 
Join Date: Jan 2005
Location: Winter Haven, FL
Posts: 210
Default neutral trim

In my -6 I always set trim to neutral for takeoff. In my plane that results in a positive rate of climb with little/no stick pressure.

The landing trim setting produces a significant pitch up if you remove pressure from the stick on takeoff/climb-out.

I was always taught to keep the plane in trim for the desired flight attitude, you never know when you'll need to remove your hand from the stick for a moment. Stuff happens.
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  #6  
Old 05-17-2018, 08:06 AM
6 Gun 6 Gun is offline
 
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Smile Trim

I trim for level flight in cruise and never touch it for landing or takeoff !
Bob
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  #7  
Old 05-17-2018, 08:28 AM
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Dan Langhout Dan Langhout is offline
 
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Default Everything He Said

Quote:
Originally Posted by n816kc View Post
In my -6 I always set trim to neutral for takeoff. In my plane that results in a positive rate of climb with little/no stick pressure.

The landing trim setting produces a significant pitch up if you remove pressure from the stick on takeoff/climb-out.

I was always taught to keep the plane in trim for the desired flight attitude, you never know when you'll need to remove your hand from the stick for a moment. Stuff happens.
+1

IO-375, Hartzell CS prop, Electric Trim. Neutral trim point displayed on Dynon Skyview EMS display.
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  #8  
Old 05-17-2018, 08:28 AM
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nigelspeedy nigelspeedy is offline
 
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Location: Tehachapi, CA
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Default RV-8 TO Trim

In my RV-8 I typically end up with a lot of nose up trim on landing so I definitely don't want to take off with it that way. For takeoff solo I set the pitch trim neutral, for takeoff with someone in the back I set it slightly nose down. I leave my flaps down after landing to make it easier to get in and out. So after start I bring the flaps back up and set the trim. I also do a check of trim/flaps/controls in my pre-take off checks.
Cheers
Nige
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  #9  
Old 05-17-2018, 08:30 AM
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Flying again! Flying again! is offline
 
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In my -10 I also set the trim at neutral for takeoff. I found out soon after I started flying it during touch and goes that if I left the trim set for landing when the power come up and the flaps retract, there is a strong nose pitch up.
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  #10  
Old 05-17-2018, 11:27 AM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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If we think about what pitch trim is for (provide a means of trimming the aircraft for a specific speed, flap configuration, and C.G. position), it should quickly become obvious that comparing settings from one RV model to another is pointless. Even comparing two of the same model may not be useful depending on the C.G. that is typical for landing.

I have walked the flight line at fly-ins and have seen trim tab positions (likely still where they were at landing), in positions from one extreme to the other (nose up and nose down).
Sometimes even a lot of nose down (a strong indicator that the airplane was at or maybe even beyond the aft C.G. limit).

For most RV's the ideal trim tab travel is such that allows about 30-35% of the travel to be nose down trim, and the remainder to be nose up trim.
This will allow for being able to trim for a normal approach speed at full flaps at C.G.'s typical for landing (though it still may not be enough when near the fwd end of the C.G. range).

The ideal trim setting for take-off will vary with C.G., but because the control forces on RV's are lighter than many production aircraft, as long as you are close, take-offs are generally not a problem and you can make a small adjustment once stabilized in a climb.
Having said that, my opinion is that every RV should have means of easily determining the pitch trim setting for take-off. Doesn't have to be fancy. For my manual trim RV-6A it is knowing that it is at neutral when the knob is about 1" aft of the fwd limit (no other indicator required).

A take-off with a grossly maladjusted pitch trim (because of having landed with a majorly aft C.G.) can cause quite a surprise, and in some conditions require some major effort on by the pilot to counter act.
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