Manual - Easier to fine tune in flight
Manual - More reliable
Electric - Weighs less
Electric - Can be integrated with a fancy autopilot
It's just up to you. Most people seem to build electric systems now-a-days. I don't think anyone who is familiar with RV's would be reluctant to buy an airplane with manual trim though. So little to no resale impact.
I did search around and read a ton of posts, just wanted to be as current as possible.
It is a decision that I need to make soon and I like to research as much as I can.
I did search around and read a ton of posts, just wanted to be as current as possible.
It is a decision that I need to make soon and I like to research as much as I can.
Actually, you can change it later. Even after the plane is flying.
I suspect there was nothing new to read on this topic. The big thing is if you go electric, where would you like your switches? Lots of people put them on the stick grip but that requires the added complexity of solenoids.
Too many production planes that I have flown had inop electric trim. They all had manual backup systems, which the RV does not. Keep in mind, you can easily over power the RV's trim, even at full deflection. It is just a pain to do so.
What I'm sure you read was that both trim systems worked and worked well. It is all up to you to pick the one you want. Either way, you can't go wrong.
... The big thing is if you go electric, where would you like your switches? Lots of people put them on the stick grip but that requires the added complexity of solenoids.
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What is actually required is a relay. I believe a solenoid is considered to be an electrical device that produces a mechanical action.
A relay is need for some of the commonly used stick grip switches because they are not rated for the current draw of the trim motor. If a speed control is used it negates the need for a separate relay.
If we are voting for a favorite... after flying many hours in many different RV's I prefer manual elevator and aileron trim. Very precise and I can very quickly get the exact amount of trim I want, exactly when i want it.
I think Bills point was that you don't have to choose right now...If you go with manual right now (makes the emp. kit cheaper) you can easily add the electric later when nearing teh end of your build if you change your mind.
In addition to a constant speed prop being a top priority....
I have electric elevator and aileron trim. The aileron uses a moving tab which I also prefer over the bias spring setup. Both are controlled by a hat switch on the joystick. This way, I don't have to reach down between several sets of legs (could be fat ones) to change trim settings.
Since I preferred to rent newer and up to date airplanes while I built the RV, most of these aircraft had electric trims. I liked them then, and like electric now. My airplanes trims very nicely.
My vote is for manual trim, you can literally feel through the knob exactly where it needs to go. When I first flew an RV with manual trim I thought, I want this!
The advantage of electric trim is you don't have to take you hand off the stick.
Flaps on the other hand I prefer electric, because the handle is just in the way, particularly with overweight passengers. I am convinced however that manual flaps are more reliable and lower maintenance than electric flaps.
My plane has manual flaps and electric trim by the way.
As this current discussion and your search of the archives revealed, trim preference has always been and will always be a matter of personal preference. Admittedly, I prefer the "sex appeal" and undisputed ergonomic advantage of electric trim activated by momentary thumb pressure on the "coolie hat" atop the joystick grip. You are new builder and will discover soon enough that making this decision is but one of hundreds of decisions you will be faced with over the course of your build. Oftentimes, nothing more than pure economics drives our decision making processes. Were it not so, we'd all sport synthetic vision displays fitted to our instrument panels. Case in point: electing to go with the comparatively cheaper stock and standard tip-up canopy option or manual flaps. Suddenly the thrifty minded decision maker can wax eloquent on superior visibility advantages or precise flap control blah blah blah. The point is once a decision is made, it is all too human to defend that choice and become an ardent supporter. If pure economics is your major concern, go with the cheaper stock manual system and live with its remotely located control knob that by design has to occupy a portion of your limited and precious cabin space. On the other hand, if aircraft empty weight is your overarching consideration, go with the more costly electric system. What I'd really like to see...thus taking raw emotion out of this perennial argument....is definitive documentation that compares the weight difference between the two trim systems. I have to believe the electric pitch trim system is considerably lighter than the manual system if only because it does not require a steel cable routed the length of the fuselage. Inch for inch, that manual steel cable and its associated hardware requirements have to weigh considerably more than its electric counterpart which is a slim interconnect wire.....and the manual trim knob assembly itself has to weigh more than the feather weight and easily installed relay required for an electric system. All things to consider...or not.
The best trim system I have used is in the DA40. It has electric trim on the stick (fairly slow) and a big honkin trim wheen between the seats (quick). Belt and suspenders approach.
The trim tab bracket receiving the trim mechanism pushrod is different between electric and manual, so a post-build change is not stone simple; you'll need to alter the bracket.
The elevator mounted servo requires more counterweight, so don't go trimming off any lead until you are sure which way you want to go.
The rocker switch supplied with the servo can be mounted on the panel (or any where else) for easy access from both seats. No need for complex stick mounted wiring or added switches. It's not really worse than involving a hand awhile on the knob, which actually can take many seconds to hit perfection. It's not an instant activity as some imply.
The only aircraft I've flown with electric trim was a Duchess, and I never got used to it. I was always chasing the trims. But it may have been the design or the particular installation. I went with the manual trim in the -6A because I'm mostly hand-flying it and the BMA autopilot doesn't make use of electric trim. But I'm going with a TruTrak in the -10 and so I'll have electric trims all around so I can make use of the auto-trim and damper functions. Hopefully I'll get used to trimming it when I'm hand-flying. On a related note, it seems most people put the trims (two, anyway) on the stick. Anyone put them on the panel and what were the results?
Hopefully I'll get used to trimming it when I'm hand-flying. On a related note, it seems most people put the trims (two, anyway) on the stick. Anyone put them on the panel and what were the results?
Having the coolie hat on the stick is *significantly* more convenient than having a rocker switch on the panel etc.. I fly a -10 from right seat and have to use a rocker on the subpanel... and it's just different and not as convenient as having a coolie right there under the thumb (which is what I'm used to).... Also, there's really no "getting used to" electric trimming... it becomes natural within minutes...
FWIW...
The RAC T3-12A-TS trim kit (servo, pushrod, rocker, LED indicator, and associated hardware) weighs in at 6.9 oz....according to my gen-u-wine Harbor Freight digital scale.
