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  #1  
Old 09-26-2018, 07:57 AM
mark960 mark960 is offline
 
Join Date: Mar 2010
Location: Long Island NY / Ft Myers FL
Posts: 43
Default Electric Elevator Trim Installation

Hi,

I am considering adding electric elevator trim to my RV9A. I currently have manual trim but would like electric so that the autopilot can automaticlly make trim adjustments. From what I'm gathering on the Van's website, you either have manual or electric, Not both.

Is there any way to add the electic trim without removing the manual?

How difficult is it to add the electric trim to a completed aircraft?


Thanks,
Mark Klepper
N1075 RV-9A
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N1075 FA81 - Ft Myers, Buckingham Field
Van's RV9A Slider
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  #2  
Old 09-26-2018, 10:44 AM
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Fearless Fearless is offline
 
Join Date: Aug 2006
Location: Crestwood, KY
Posts: 835
Default Am I misunderstanding?

Mark,

The autopilot servo would connect to the elevator push tube. I have the electric elevator trim on my plane. You would have to remove the cable from the trim in order to install the trim servo in its place. Then you would need to run the five wires from the trim servo to the front of the plane to your switch, power and ground. The trim servo is the one Ray Allen sells.
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  #3  
Old 09-29-2018, 12:16 PM
mark960 mark960 is offline
 
Join Date: Mar 2010
Location: Long Island NY / Ft Myers FL
Posts: 43
Default

I already have a Pitch Servo in the tail for a Trio AutoPilot. The pitch servo has an output that will directly control an electric trim.

Just hoping I could leave the manual trim in place. (And working) It looks like you have to choose either Fully manual trim, OR electric trim only. Is that correct???
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N1075 FA81 - Ft Myers, Buckingham Field
Van's RV9A Slider

Last edited by mark960 : 09-29-2018 at 12:19 PM.
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  #4  
Old 09-29-2018, 12:48 PM
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az_gila az_gila is offline
 
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
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Smile

One option, used by some early -6 builders, is to buy a shorter push-pull cable and mount the Ray Allen trim servo on the flat deck under the fiberglass tail fairing.

This way there is no modification to the metal work of the horizontal tail.
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  #5  
Old 12-07-2018, 07:31 AM
KRE KRE is offline
 
Join Date: Dec 2017
Location: Madison, VA
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Are there any drawings for the installation of electric trim on a RV-9 ?
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  #6  
Old 12-07-2018, 10:50 AM
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Steve Melton Steve Melton is online now
 
Join Date: Apr 2011
Location: Cincinnati, OH
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I've been flying electric elevator trim for the past 5 yrs and I like it except that it needs to be slowed slightly for cruise adjustments. I decided to use the Ray Allen speed reduction module, purchased but not installed yet. I may install it at the rear deck adjacent to my trim servo connector.
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RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 700+ for all

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  #7  
Old 12-07-2018, 11:24 PM
Tankerpilot75 Tankerpilot75 is offline
 
Join Date: Jan 2015
Location: Oklahoma City, OK
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Quote:
Originally Posted by az_gila View Post
One option, used by some early -6 builders, is to buy a shorter push-pull cable and mount the Ray Allen trim servo on the flat deck under the fiberglass tail fairing.

This way there is no modification to the metal work of the horizontal tail.
This is what I did when I converted from manual trim to electric trim. It works great. The push-pull cable needs to be about 28 to 30 inches in length for this to work optimally. All cable parts can be purchased through Aircraft Spruce.

I highly recommend using Pat Hatches “Ultimate Trim Relay Board (UTRB)” and mounting it under the copilot’s seat. The use of a trim relay board prevents both pilot positions from inputting trim control inputs at the same time thus either cancelling each other or worse burning up the trim control motor(s).

At the time I converted my aileron and elevator trim from manual to electric I also installed five button Tosten military style grips. (Tosten is another great vendor who will help you think through the grip/button issues.) The UTRB board really helped in the wiring up of the additional switches. My grips now have buttons for PTT, ident, flaps/com swap - depending whether it’s the pilot or copilot stick, freq swap and autopilot engage/disengage. This makes flying real easy and I can pretend its a military jet trainer ie T37 or T38. (I loved flying the T38 when I was a youngster.)

Its sounds like a major wiring job but it actually wasn’t too bad with Pat Hatch’s assistance. He guided me through the process via emails and a few phone calls. He lives in Florida and I live in Oklahoma and my electrical knowledge is minimal. (Accountant by education - good with money/dumb with sparks!) However, Pat still successfully guided me through this process pretty easily. The actual work took two plus long weeks of almost daily effort but I absolutely love the results. By the way, I don’t use a speed control switch on my elevator trim. Didn’t need it.

PS: Document via schematics, pictures and written notes this change. You may need to modify or repair something later on. I also highly recommend getting a small heat printer at Office Depot or some place else plus shrink tubing and label all wiring you install or hook up. Steinair has some great UTube videos on how to do aircraft wiring and will also sell you the tools, wire and connectors you’ll need.

Don’t be intimidated by the project. It’s a very doable and well worth the effort.
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Last edited by Tankerpilot75 : 12-07-2018 at 11:33 PM.
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  #8  
Old 12-08-2018, 12:49 AM
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bruceh bruceh is offline
 
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Location: Ramona, CA
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The trim tab horn on the elevator only has a single connection to the trim manual cable (or Ray Allen actuator for electronic trim). The geometry is different depending on electronic or manual. Take a look at drawing 4 in the plans. You might need to build a new trim tab if the trim tab horn E-918/E-917 has been trimmed as the plans require. The electronic trim kit from Van's has all of the other pieces you need.

Wiring it all up is easy. The electronic trim wires basically can follow the path that was used by the manual cable when you remove it. There are 5 wires to the actuator and you can buy an appropriate length of multi-wire cable (WC3) with all of the correct color codings to match the Ray Allen wires. Two of the wires are +/- voltage to move the motor up/down, and the other 3 are ground, a reference voltage and a return sensor voltage to drive the display for trim position indication.
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