Elevator Trim (Manual vs Electric)

bmurrish · Post by **bmurrish** » Sat Jan 22, 2005 11:57 pm

I am curious what type of elevator trim activation others are using. I prefer manual over electric, but have had limited exposure to the vernier control type that comes standard with the kit. I have flown aircraft (mostly twins) that utilized this type of control for rudder trim and really didn't care for it. Is it worth the extra $240 for the electric trim or does the vernier controlled trim work just fine? The check for empennage kit is going in the mail Monday morning, so I need to make the decision soon. Finally going to stop dreaming and start building.

Thanks for your opinion,

Bill Murrish
929BM(Reserved)
RV-8 Preview Plans

Post by **Spike** » Sun Jan 23, 2005 12:27 am

Woohoo, good for you! I chose manual because I wanted simplicity. Ive also found with my limited experience with electric trim that it has a tendancy to move to fast for me. I like to be able to just massage the plane into trim and didnt want to fiddle with switches and stuff. Keep in mind that this is experimental and you can choose a different cable actuation mechanism than the vernier method. That can be decide later though as you wont need that for a long time.

hngrflyr · Post by **hngrflyr** » Sun Jan 23, 2005 1:40 am

My RV-6 has electric trim. If I would have been the builder, the trim would have been manual. After flying with electric trim, I've gotten used to it and its just fine. I think the wiring and servo are likely lighter in weight than manual trim would be.

captain_john · Post by **captain_john** » Sun Jan 23, 2005 7:29 am

I think the -8 only comes with electric. Need to check Van's site.

Anyhow, I got electric. I figure, it is easier to route a wire to the tail than a cable. The MAC servo isn't hard to figure out. A little head scratching, but it goes together.

CJ

captain_john · Post by **captain_john** » Sun Jan 23, 2005 7:39 am

MY BAD!

It IS available with the crankie trim!

Well, pros and cons?

I guess no fuses to blow with the crankie system.

I understand this is all as obvious as the nose on your face.

Personal favor I guess.

CJ

arffguy · Post by **arffguy** » Sun Jan 23, 2005 6:57 pm

Most of the guys I know with electric trim complain that it moves too fast so they end up tapping the button numerous times for awhile to get where they want it. It's kind of annoying to me as the passenger. Matronics sells a device to slow the servo down:

http://matronics.com/governor/index.htm

The folks with manual trim say it is easier to get the trim where you want it faster. Manual trim tabs seem to have more slop when you hold the elevator and wiggle them. I don't know if this makes much difference but seems to be something one of my friends (tech counselor) seems to do to everybody's airplane. The electric trim adds more weight and complexity to the left elevator itself. Plus a little more parts cost. The electric trim also gets rid of the control between the seats just as electric flaps do. I am going with the manual trim myself.

Make sure when you build the left elevator to use the correct control horns on the trim tab too. There is a difference.

Dan A · Post by **Dan A** » Sun Jan 23, 2005 9:33 pm

When I got my empenage kit it had the electric trim with it. I used the MAC servo relay pack and buttons on the stick. To take care of the trim speed I installed a variable voltage regulator, Also sold by the servo company and wired up a micro switch triggered by the flap control arm so when the flaps are up the elevator trim is at about half speed and when the flaps are down and you need the faster action on the elevator trim, you have it. I hope that helps tose wanting the electric trim. But the manual trim is more simple to install.
Dan

728GD · Post by **728GD** » Mon Jan 24, 2005 11:59 am

I went with the manual trim. RV's are so light on the controls I really don't think the electric is required. When I trim up, I generally don't have to move the knob more than an 1/8 turn from take off position. It is really sensitive. I also am a firm believer in the kiss approach. If you go with electric make sure you can slow down the servo, and it's just one more thing to fail. You do not need much movement on the trim tab to trim up the airplane.

Dale

bmurrish · Post by **bmurrish** » Mon Jan 24, 2005 12:12 pm

Everyone-Thanks for all the useful information. I decided to go with the manual trim. Checks in the mail.

s10sakota · Post by **s10sakota** » Wed May 25, 2011 11:11 am

Hey guys,

I'm getting ready to order the tail kit too and was looking for a thread on manual vs electric.

Does anyone have a picture of manual trim knob in the cockpit? I have no idea what it looks like.

I like the idea of electric but one of my goals for this RV-8 is low cost and simplicity so I may go with manual.

If anyone can post a pic I'd appreciate it!!

Thanks

Joe Parish · Post by **Joe Parish** » Wed May 25, 2011 4:17 pm

If you jump over to the classified section, the RV-7 that is posted for sale(Chad's RV-7) it can been seen in the 2nd & 3rd pics down in between the seats.

s10sakota · Post by **s10sakota** » Wed May 25, 2011 4:21 pm

Great! I see it now, thank you. Electric trim it is for me!

RivetBangers.com

Elevator Trim (Manual vs Electric)

Elevator Trim (Manual vs Electric)

I need a pic of manual trim