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  #1  
Old 03-19-2017, 03:04 PM
rjcthree's Avatar
rjcthree rjcthree is offline
 
Join Date: Jan 2007
Location: Bay Village, OH
Posts: 663
Default Trim tab guidance for first flight

My first flight is rapidly approaching. The plan is to go at 1427 lbs and a cg of 79.72" calculated. This is solo, 24 gal of useable fuel, a little bit of baggage. It's an RV-9A/O-320/Sensenich.

How do people set their trim tabs for takeoff?

Thanks.
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The project turned 15 years old 2016sep29.
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  #2  
Old 03-19-2017, 03:06 PM
YellowJacket RV9 YellowJacket RV9 is offline
 
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Location: Clearwater, FL / KZPH
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You will be fine setting it in the neutral position, and can dial it in from there. I have settled on about 1/2" nose down trim from neutral. I have same setup as you.

Chris
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  #3  
Old 03-19-2017, 05:06 PM
cajunwings cajunwings is offline
 
Join Date: Jun 2007
Location: new iberia la
Posts: 453
Default Trim setting

Neutral setting is a good place to make first takeoff. I have found that even when out of trim the control forces are easy enough to manage. RV9A with IO320 and Hartzell likes slight bit of nose up for takeoff, about 1/8" tab deflection from neutral. Some folks like a little more up trim to make rotation easier. I think it makes the most sense for trim to be set so that plane is in trim after liftoff and no immediate re-trimming is needed. I will add that compared to most any other small aircraft including the 6A the 9A gets very sensitive in pitch in the landing flare and will give you a higher than average sink rate below about 60 kts.

Don Broussard
RV9 Rebuild in Progress
57 Pacer

Last edited by cajunwings : 03-19-2017 at 05:16 PM.
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  #4  
Old 03-19-2017, 06:39 PM
krw5927 krw5927 is offline
 
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Location: Wichita, KS
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Neutral for me for every takeoff, regardless of loading. While I wouldn't recommend it for a first flight, I did find later on that I like to use a touch of flaps for takeoff, setting the flaps equal to a fully-deflected down aileron. There are several discussions here on VAF about takeoff flaps.

Again, not worth fussing with for first flight. There are enough other things to be paying attention to.
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  #5  
Old 03-19-2017, 06:51 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Posts: 3,340
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Neutral trim with my o320 just happens to give me my 85kias Vy.
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  #6  
Old 03-19-2017, 08:06 PM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Control forces on the 9A are light enough that you'll be airborne for a solid 2 minutes before you even realize you are pushing/pulling one way or another. Set it for the neutral position and worry about the other stuff. Once you get it trimmed correctly, it's truly a 3-finger airplane.

By the way - here's a vote for having a ground crew handy on first flight. I was busy flying the airplane and transmitting what I was doing on the radio to my guys on the ground, who were furiously taking notes. They wrote down stuff I don't even remember saying. It's good to have other eyes in the cockpit with you on the first flight, even if it's at the other end of a radio. Adrenaline does weird stuff.
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Last edited by airguy : 03-19-2017 at 08:09 PM.
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  #7  
Old 03-20-2017, 12:54 PM
jfogarty jfogarty is offline
 
Join Date: Sep 2005
Posts: 106
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Neutral trim on take off with 0320 and 3 blade catto prop. At about 300' a little down trim works good for me. My electric trim works great.

Jim Fogarty
RV-9A Flying
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  #8  
Old 03-22-2017, 10:23 AM
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rjcthree rjcthree is offline
 
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Location: Bay Village, OH
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Default Thanks everyone

Thanks everyone. Neutral trim it is. I'll have the gopro from inside the AC recording commentary too. Fly safe....
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Rick 90432
The project turned 15 years old 2016sep29.
Airworthiness inspection 2016sep30....passed!
First Flight 2017apr23 - let Phase 1 begin!
2011-2017 VAF contributor
Dog is my copilot, rest in peace 2015APR28. I miss that dog.
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  #9  
Old 03-22-2017, 07:07 PM
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bruceh bruceh is offline
 
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Location: Ramona, CA
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Hold that stick all the way back, throttle up, count to 2 and the nose wheel will be off the ground. Relax the back pressure to keep the nose wheel off the ground and at around 65 Knots you'll be flying!
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