electric trim versus manual

[dlloyd3]

What are the pros & cons of electric elevator trim versus the manual trim cable?

[Brian130]

Originally Posted by dlloyd3

What are the pros & cons of electric elevator trim versus the manual trim cable?

http://www.vansairforce.com/communit...=electric+trim

http://www.vansairforce.com/communit...=electric+trim

[Vince Koehn]

I too found the elevator trim way too touch even with just "bump" inputs. However I fixed it..... when I built my airplane I put a little contact switch so that when the flaps came up the flap rod would hit it and shut the flap switch off...works good. When I taxi in I just hit the switch up and forget no remembering to switch it off. Later after discovering my elevator trim was way to touchy I tied into this same flap circuitry and now have a speed control so that when I am in flight with flaps up the elevator trim is real slow and easy to adjust but when the flap switch is bumped and the flaps are going down the elevator trim switches to a high speed which is better for the landing phase...love it!

[Rick6a]

Originally Posted by dlloyd3

What are the pros & cons of electric elevator trim versus the manual trim cable?

I have 2 axis electric trim (elevator and aileron) activated via a "china hat" on an Infinity joystick grip. The LED indicator lights mounted on the instrument panel show how much deflection is cranked in at any given time. Unlike some RV-6A drivers, I find the elevator trim sensitivity to be a non-issue whether at full throttle or in the pattern. This may be due to the adjustment screw being set just right on the ES-MK-111 (speed controller and relay deck) from the get go. I have not felt the need to readjust it. My guess is that sensitivity may be a problem if this optional component is not installed. Until I started flying my RV, I had no real concept of how just how much difference a few gallons imbalance in each fuel tank can effect the centering of the joystick. The electric aileron trim is often used to compensate for fuel imbalances at any given moment. I could not be happier with my electric trim system and plan on installing exactly the same components on my RV-8 kit someday.

I have flown an RV-6A with manual elevator trim and it works perfectly fine. My only issues with the set-up are that it is a rather large assembly and I didn't want a center console installed on my plane (per plans) and at least on the particular aircraft I flew, you had to neutralize the trim tab during preflight by visually sighting it and adjusting the trim wheel in the cockpit because no cockpit elevator trim indicator of any sort was installed.

Like everything else, whatever you install is a choice that ultimately comes down to personal preference.

Rick Galati RV-6A "Darla" 36 hours

[gmcjetpilot]

Electric trim is lighter than the manual trim. The manual trim cable is long and the bracket on the elevator is heavier, so you will use more lead to balance you elevators, not much but it adds up.

As far as touchy I never had a problem but have heard people complain. The fancy solution speed trim control. At high speed you want it to move slower and in the pattern faster. Several people make little control boxes that slow down and/or speed up the trim motor. They can work off off of airspeed switch, flap position switch or manual select switch:

http://www.f1-rocketboy.com/tcm.html
OR
http://www.matronics.com/governor/index.htm

This one has flap position control:
http://www.aircraftextras.com/FPS-Plus.htm

Personally I never had an issue. At speed a jab would make fine adjustment just fine, and when I was slow in the pattern an extra second or two to hold the trim switch was never an issue. Go with the electric is my advice. With the factory pre-cut parts to install an electric trim motor in the elevator, electric trim installation is straight forward.

Cheers George

[Build9A]

The manual trim is simple and easy to install (except maybe snaking it through the elevator). It is responsive and operates very effectively. Less to wire and less to break. I like my manual trim. This may be like the tip-up or slider discussion. Personal preference. Jack

[Highflight]

On the other hand...
I'm going with electric trim for elevator because it's used quite often.

But I see no reason to go with electric aileron trim because the only reason it's used is for fuel burn. For that, simple manual trim seems to be the way to go since you might only jiggle it 3 or times during a flight, but the elevator trim is tweaked almost constantly.

My inflationary .07 cents.

[gvgoff99]

I personally like manual for the following reasons:

Simple, easily understood and will still be working twenty years from now. If the electric has a problem it will take longer to figure out what is happening (broken wire, faulty switch, faulty motor, corrosion on a contact, mechanical linkage, etc.)

I just like the KISS principle here (and most other places where there is a mechanical setup that I may have to trouble-shoot some day.)

It is all personal preference. Your just adjusting the trim. Both systems will do that job well.