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Electric or Manual Trim

krjcolo

krjcolo

Active Member
I am about to order my empennage kit, I am wondering besides the cost of the electric trim what other people think the benefits are of it over the manual?
Thanks,
Kim
 
Get a cup of coffee, do a search, and sit back and be prepared for a very long read. This is an endless debate topic widely discussed....
 
There is no benefit with electric trim... manual trim is simple and effective, actually easier to hit and maintain the sweet spot. :D
 
Manual

We bought an RV-6a with electric trim and it was difficult to set it precisely, so when I built my own 6a I naturally used manual trim which is very precise and easy to use.

Downside of manual trim? It weighs more, that 's it... YMMV
 
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Well, there are other considerations.

If you plan to use an autopilot that has altitude pre-select / vertical speed select, etc. it's best if you have electric elevator trim -- the autopilot will auto-trim the airplane to establish climb rate and not continuously load the AP's servo.

Also, I have no problem at all trimming my airplane with electric elevator trim. On the other hand I have flown a -6A with manual elevator trim and it worked fine. It is a little awkward at first as it's different from most manual trim systems but it works great.
 
LifeofReiley said:
There is no benefit with electric trim... manual trim is simple and effective, actually easier to hit and maintain the sweet spot. :D
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Electric trim is lighter...

I have a speed controller on mine to slow it down and never have any problem hitting the "sweet spot".
 
Until...

Walt said:
I have a speed controller on mine to slow it down and never have any problem hitting the "sweet spot".
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the failure of the servo, controller, fuse, breaker or even a broken wire or pin comes into play. The manual cable is pretty much bullet proof. Keep it lightly lubed and it works very well. As to weight, well at 1059 lbs, I wouldn't say I have a heavy plane. :) The cable weight is also distributed well thoughout the fuse.
 
I currently have two -7s (wanna buy one?), one electric the other manual. Properly rigged, it's easy enough to find the trim sweet spot with either. There are a couple of details not often brought forth in this endless debate:

There's more clutter in the way with manual trim, big knob, loopy cable, grope between the seats oozed out with American super-sized thighs for roll trim.

Electric takes longer to install with greater complexity, especially if you use a coolie hat and/or speed controller other than the supplied switches (that I mounted in the panel right above the throttle and next to the flap switch).

A serious advantage electric roll has over manual is that the trim setting won't creep. Manual relies on friction to hold position, not a good design for an airplane.

Manual pitch has a range of motion advantage over electric. With forward c.g., I run out of electric trim with full flaps/slow, manual covers the entire c.g. range.

John Siebold
 
My 6A has been noted by other pilots, for it's excellent "trim" attributes. It's "electric" for both pitch and roll. The four way hat switch is on the stick, which allows one hand on the throttle, and one on the stick. I wouldn't have it any other way...

Note: my roll trim is a servo tab on the aileron. No bias springs.

L.Adamson --- RV6A
 
Okay...

Well, I have a good friend flying an RV7 with less than 120 hrs and his electric trim failed just after takeoff. In the fixed position it was in, it made for a creative landing approach. Guess we'll see what part failed.
 
My flap system has the capability of setting the elevator trim for its given down/up position. This is only possible with the electric. In Take off and landing, each time I set my flaps, I am already trimmed as well. Also the advantage of weight, less clutter, creeping and there is less free play in your trim tab. I understand manual trim can have as much as a 1/4" free play in it due slack in the cable assmebly
 
LifeofReiley said:
Well, I have a good friend flying an RV7 with less than 120 hrs and his electric trim failed just after takeoff. In the fixed position it was in, it made for a creative landing approach. Guess we'll see what part failed.
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I'm one of those guys that doesn't bother to trim for landing. Honestly I don't know how folks have have time to normally. I would guess from the time I enter down wind to the point of touch down can't be more than a minute (close in pattern) and I personally prefer to have a little pressure on the stick, gives me a better "feel".

So I guess what I am saying is... why would it make for a "creative" approach with no trim? It's not like it takes both hands on the stick to flare an RV :confused:
 
Walt said:
I'm one of those guys that doesn't bother to trim for landing. Honestly I don't know how folks have have time to normally. I would guess from the time I enter down wind to the point of touch down can't be more than a minute (close in pattern) and I personally prefer to have a little pressure on the stick, gives me a better "feel".

So I guess what I am saying is... why would it make for a "creative" approach with no trim? It's not like it takes both hands on the stick to flare an RV :confused:
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Yep..............my takeoff trim, is the same as my landing trim. I never reset..............and just look to see that it's in it's normal position during the walk around. Normal is 1/8 to 1/4" off of center, at worst.

However, I do remember the Piper Archers from the old days. It seems, that the nose needed to be re-trimmed up, or it was quite a pull on the yoke. I never have had that thought, in the 6A.

L.Adamson --- RV6A
 
I have electric and I prefer it but there are times when it can sneak up on you. For example, during a touch and go I keep the plane rolling while the flaps come up, I sometimes forget to trim it to neutral after trimming nose up on final. There is a rude reminder when you give her full power....it almost wants to stall unless you apply generous forward stick. I imagine this would be the same if you forgot to neutralize the manual trim also but if the electric failed in this position...it would be challenging.
 
tkatc said:
I have electric and I prefer it but there are times when it can sneak up on you. For example, during a touch and go I keep the plane rolling while the flaps come up, I sometimes forget to trim it to neutral after trimming nose up on final. There is a rude reminder when you give her full power....it almost wants to stall unless you apply generous forward stick. I imagine this would be the same if you forgot to neutralize the manual trim also but if the electric failed in this position...it would be challenging.
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Tony.. Try not using trim in the pattern and see how you like it. I use whatever my cruise trim was and never touch it in the pattern (the only exception to this is OshKosh where I'm flying so slow for so long). This method also prevents any surprises on T&G's.
 
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