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Do I need electric roll trim?

dstates

Well Known Member
My wing kit is arriving next week and I didn't order electric roll trim (yet).

For those already flying their RV-14 with electric roll trim, do you use it often?

For those flying without electric roll trim, do you wish you had it?

Thanks!
 
I use it all the time - aileron roll trim varies with fuel amount in each tank as well as weight of passenger (or no passenger). Plus, the autopilot roll servo (I have Garmin) will drive the roll trim servo when enabled.

_Alex
 
I removed mine as I didn't feel it was needed. There is an imperceptible roll to whichever side has more fuel but its so light I never feel it when hand-flying unless I let go of the stick. AP roll handles everything when not hand-flying. I couldn't bring myself to put a spring on any controls surfaces.
 
Is the question electric or manual trim? Or trim or no trim?

The RV is a very nimble aircraft, and aileron trim will be most welcome, and will increase safety. A bit out of trim, and you let go of the stick, you will be in a turn very quickly. I see in your sig you are flying a 170 - they are extremely stable, and IIRC, they drain the tanks equally. Not so on the RV.

Electric is nice since you can have it on a hat switch on your stick, and can connect it to the AP which will trim for you as you burn fuel. Also, as mentioned, trim will be helpful when you fly alone.
 
Electric trim

Not installing electric trim on such a nice airplane is like ordering a new Cadillac with manual transmission and non powered brakes and steering
 
Not installing electric trim on such a nice airplane is like ordering a new Cadillac with manual transmission and non powered brakes and steering

I only wish I could buy a Hi End car with manual transmission!
 
To Mel

At the Atlanta Airport old Ford plant there is now a Porsche Experience center where customers can select various car models to test drive. I’m told that most he-men want the manual trans models but within thirty mins want to trade fir the auto trans models.

Relates to RVs because it’s close attraction to the Falcon RV Squadron at KFFC:)
 
At the Atlanta Airport old Ford plant there is now a Porsche Experience center where customers can select various car models to test drive. I’m told that most he-men want the manual trans models but within thirty mins want to trade fir the auto trans models.

Louise just gave me a certificate to do the “Experience” in LQ for my birthday. One of my good friends who has been in racing all his life said just start with the automatic so I can concentrate on lines and braking points instead of spending 95% of my time shifting! The world changes….

On aileron trim - I am always surprised that even though we have electric trim on all three RV’s, I rarely touch it. Of course, two of them are centerline seating, and I change tanks every thirty minutes. And when I am flying the side-by-side, it is usually cross-country, and the autopilot is flying, so I don’t care….. but I wouldn’t remove it because every once in awhile, I play with it.
 
On the RV-9A, don't need aileron trim. However, would like to have rudder trim, especially for high speed descents at low power, but don't really *need* it, either.

My take? Add it if you want more gadgets, but if you want simplicity, the extra workload of not having aileron trim is insignificant. Rudder trim is far more desirable than aileron trim. My plane has neither one...
 
Need or want!

I certainly want it, especially that is fairly inexpensive. It is almost the difference between a car with power steering and without.
 
Now, that Cadillac comment takes me back a few years
What a story to tell.
Back in 1969, I was a new mechanic (apprentice) at a Cadillac dealership.
I was given the task of pre-purchase checkout of new vehicles.
NO KIDDING here comes a new Cadillac Coupe-Deville with a 6 cylinder three speed stick on the column. No power nothing, an AM radio, Not even any hub caps.
It was a real bare bones car. Oh ya it even have vinyl floor mats.
Crazy experience, What a laugh, Art
 
I change tanks in the -7A every 4 gallons and I definitely use the trim. Even more so when there is a person in the right seat. Definitely don't skip the trim.
 
First Mod after Phase 1

OK first mode after phase one will be trim tabs for aileron and rudder trim.

Well, first after flying my a$$ off.
 
I appreciate the excellent feedback so far.

One person noted I currently fly a 170 which is stable and drains fuel evenly, that is correct. My other main flight experience is in a Cirrus SR20 and Piper Archer. The Cirrus had electric roll trim, but I don't remember ever using it. I probably used it the most after accidentally hitting the switch. The Archer didn't have roll trim at all.

Like Paul said, if it is cross country time it is likely autopilot time. However, I'll be giving plenty of local/short rides in this and someday hope to do some simple aerobatics.

As a mechanical engineer I probably over think things, but I do agree with the comment made earlier about springs. I also want to consider the benefit of having electric roll trim compared to the risk of trim runaway.

There are many planes without any roll trim, I guess my question is about the sensitivity of an RV-14. If you start off the flight with neutral roll trim, how out of trim can it get? Is it really noticeable when hand flying?

Thanks for all the feedback... Any other thoughts?
 
...
There are many planes without any roll trim, I guess my question is about the sensitivity of an RV-14. If you start off the flight with neutral roll trim, how out of trim can it get? Is it really noticeable when hand flying?

Thanks for all the feedback... Any other thoughts?

If your car pulled left or right when you let go of the wheel driving down the highway, you'd get it fixed. Same with trim on your aircraft - no idea why you'd want to fly it out of trim if there is an extremely reliable, inexpensive way to have it perfectly in trim all the time. Those are my thoughts, worth what you paid for them. :)
 
The new high performance Cadillac CT-V Blackwing comes with a manual transmission. An automatic is available but the manual is the preferred option.

If I could find one, I would buy one. It is a very limited production car.

I watched the AOPA Wing-to-Wing video on the making of Top Gun. It was mentioned that the Blue Angles planes are fitted with a spring bias system on the stick to eliminate the small null zone when the stick is centered.
 
Not to get off topic but is rudder trim an option? My understanding is the most that is available is yaw damper with a 3 axis autopilot.
 
Your autopilot will thank you. My G3x is always moving it a little. It uses it a lot more than I do when hand flying.

You can feel it but it is still very flyable without using it.
 
On aileron trim - I am always surprised that even though we have electric trim on all three RV’s, I rarely touch it. Of course, two of them are centerline seating, and I change tanks every thirty minutes. And when I am flying the side-by-side, it is usually cross-country, and the autopilot is flying, so I don’t care….. but I wouldn’t remove it because every once in awhile, I play with it.
I'm with Paul on this one, and I'm especially not fond of the trim system in the 14, be careful that the springs don't wear into the aileron torque tube.
 
I hate 'Bitchin Betty'
---- when my buddy is flying along in AP mode & his EFIS is for ever screaming for him to 'trim up' 'trim down' 'trim left' 'trim right'. He has electric trim but doesn't have it automated or integrated...

Based on how mouthy Betty is, there must be a lot of minor trim adjustments that happen in a typical flight. I don't have a Betty in my plane so I must dumbly accept a LOT of slightly out of trim fly time enjoying every silent minute of it:)
 
To the OP, having an RV7 with AP and no automatic trim, the AP will cause stick "tick" when the roll trim is not balanced. If observed carefully the stick points to the trim button needing action. Tick -tick - tick.

The above only true with stepper motor style AP, the Garmin does not do that.
 
be careful that the springs don't wear into the aileron torque tube.
I found the oem clips will allow the springs to rub on torque tube. Made two new ones that were approx 1/4” longer and 1/8” taller. Found it easiest to install springs to servo arm on workbench and then reinstall arm to servo once torque back in the wing. Washer wrenches were helpful for servo arm reinstall. I abandoned the micro molex and will plug terminals in to each other and heat shrink with a piece of fishing line under heat shrink. If I ever have to remove, pulling the fishing line cuts the heat shrink. No Olfa knife while laying on back.
C278C336-7C5C-4A5A-B58B-16C280B582C0.jpg

4BDA9A21-4674-493B-9A82-1B01DAD47B75.jpg
 
I don’t know if the RV14 has a manual roll trim option, but that is what I have on my new RV6, and it works very well. My GRT EFIS doesn’t have the option of driving the trim motors, so I’m not missing out on having my autopilot command trim automatically. If I’m out of trim the EFIS will ask for trim (visually with an arrow unless I’m way out). I’ve never seen it ask for roll trim, only pitch trim occasionally. When hand flying and a little out of balance laterally, it will roll if you take your eyes off from flying for a few moments, so roll trim is nice to have. I can trim mine out in smooth air and it will just stay there for a considerable amount of time. It makes hand flying a little more enjoyable to me when actually going somewhere.
 
Never flown the 14 but if they are in line with most of the other RV line, then its likely that you will never get it perfectly trimmed without some kind of cockpit adjustable scheme. Fuel load will screw up the trim, and some will even claim that reaching across the cockpit will initiate a slight roll. That is certainly true with my Rocket, but I did remove the trim on that airplane ("remove" - AKA "built a new aileron"). It was an external tab and I did not like the reduction in flutter margin for that scheme (weight, hinges, linkage, servo slop, etc). Also had a spring cartridge in the RV - 8 and was not a fan. In the end, the autopilot handles roll trim for those long cross countries and for the hand flying I do (acro, form, fooling around), the slight wing heavienss is not enough to notice.

I also removed the rudder trim on the Rocket (installed a new rudder) for the same flutter concerns, and I don't miss it one bit.

Thats my choice and I am only offering it as food for thought.
 
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Need install instructions....

Can anyone post up pictures or install intructions for the electric aileron trim? Im installing in my 9A and can't find any documentation. Thanks!
ed
 
For the -14 but perhaps will give you some idea.

Thanks.... It appears the 14 has the aileron trim in the wing. The 9 (and I'd guess the 7) have it in the forward fuselage. I'm replacing the manual setup and wondering how the trim motor attaches to the springs.
 
Thanks.... It appears the 14 has the aileron trim in the wing. The 9 (and I'd guess the 7) have it in the forward fuselage. I'm replacing the manual setup and wondering how the trim motor attaches to the springs.
The manual trim in a 6, 7 and 9 work great and even better than the electric. It is super easy to install.
The installation location for the arm/actuator is just forward of the flap housing between the seats.
This option is not available for the 14, otherwise I would be putting a manual trim instead of electric.
 
Another vote for "no aileron trim". I didn't have one on my -8. Never wished I had one. Change tanks every 30'. When flying aerobatics you're rarely straight and level and you are using visual queues to level wings when you are. Autopilot takes care of it on cross countries. The thought of springs in the system makes me a little nauseous:eek:
 
I only wish I could buy a Hi End car with manual transmission!

My 80's 911 has a manual trans and manual steering, though does have power brakes. Incredibly fun car to drive. My bmw M5 (quickest 0-60 for a production car when released in 2000) is what I would call high end and was not even available with an auto trans. They correctly figured no one with a car like that would want an auto trans.
 
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They correctly figured no one with a car like that would want an auto trans.

And yet, the 2023 Corvette is only available with an automatic. Too little demand for the manual.

Back to the topic. My -10 has neither aileron nor rudder adjustable trim. (Rudder has a fixed trim wedge). When hand flying, I can tell where most of the gas is, or where the heavy passenger is - it’s often out of roll trim, slightly, one way or the other. (My (Trio) autopilot flies great, handles these imbalances with no complaint.) Hand flying vfr works fine. But, when hand flying an instrument approach, I do wish I had roll trim. It’s just easier when the plane is perfectly trimmed. When I owned a 182 that was slightly out of balance in roll, I would use the adjustable rudder trim to raise the heavy wing, and fly approaches in a slight slip. It was definitely less work that way. So, if I was building now, I’d include the roll trim.
 
And yet, the 2023 Corvette is only available with an automatic. Too little demand for the manual.

Back to the topic. My -10 has neither aileron nor rudder adjustable trim. (Rudder has a fixed trim wedge). When hand flying, I can tell where most of the gas is, or where the heavy passenger is - it’s often out of roll trim, slightly, one way or the other. (My (Trio) autopilot flies great, handles these imbalances with no complaint.) Hand flying vfr works fine. But, when hand flying an instrument approach, I do wish I had roll trim. It’s just easier when the plane is perfectly trimmed. When I owned a 182 that was slightly out of balance in roll, I would use the adjustable rudder trim to raise the heavy wing, and fly approaches in a slight slip. It was definitely less work that way. So, if I was building now, I’d include the roll trim.

On my RV7 I hardly ever used the aileron trim. So in the RV10 I put the roll trim on the center console (figuring it would be rarely used) and just have pitch trim on the stick. Big mistake. I’m constantly reaching and fiddling with the roll trim. More so now that I have ER tanks.
I’m going to put a coolie hat back on the stick for both next time I have all that apart for annual.
 
Roll trim can't hurt. If you have an asymmetric load for some reason, or if your build comes out with a heavy wing. And if you sometimes need the trim, it will save the AP servo's lifetime.
 
About 9 years ago, I did a mountain flight in my Rocket from Kamloops to Victoria BC. Most of it with the autopilot /autotrim flying, making all the expected minor course correction.

For some reason, the Rocket missed the turn at Hope, BC. It was slowly converging on the new course, but clearly something was wrong, so I took control.

The shear pin on the Dynon roll servo had sheared likely due to turbulence climbing out of Kamloops (the Tower even called me after takeoff with a SIGMET update). All of the minor course corrections were likely performed by the autotrim enroute.

Now, this was my own design of an autotrim system, predating Dynon’s version, so I don't know if the factory version works the same way.

So, I am putting the same system in my new build, which includes electric 2-axis trim. I will be running some experiments to implement altitude and heading hold just using trim with RAC servos (no heavy duty autopilot servos engaged).

To make a short story long, that's why I want electric roll trim!

Vern
 
And yet, the 2023 Corvette is only available with an automatic. Too little demand for the manual.

.

I suspect as the calendar keeps flipping, fewer and fewer people have an opportunity to learn how to drive a manual; eroding the demand for them. Modern advances in AT technology has also eliminated many of the advantages of a manual in a high performance car. I suspect the AT in that corvette can shift faster and harder than a manual could for the vast majority of drivers.
 
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Also, it's easier to meet the CAFE standards with an automatic. More gears (usually) and the programming can be optimized.
 
I have a trim tab based electric aileron trim in my vintage RV6. Use it all the time, and would dearly miss it flying cross country (but I don’t have an autopilot).

I would certainly install some trim even if planning an autopilot.
 
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