electric trim tab actuator

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Re: electric trim tab actuator

Postby R Rinker » Tue Feb 19, 2013 12:30 am

I have 'no' experience flying a Highlander, but in the aircraft I fly a trim tab position indicator is essential for take off.
You don't need it for in-flight adjustments as that can be done by feel. But for take off it's a different ball game.
My experience, and that or some dead buddies, is that there is a specific airspeed at which trim tabs and certain Airflows become instantly and powerfully effective. In an aircraft that is right on the edge of it's weight and balance envelope on takeoff, if the trim is accidentally left at full deflection where it may have been at landing, (remember in my aircraft at gross and edge of W&B) you won't feel effect until you're off & start to climb. Then instantly & violently u will go through a life changing experience that you'll never forget.
I can't imagine anyone signing off an airplane that has no tab position indicator. Even if the builder works around it, what happens in the future if some else flys it? This is one thing u do not want to be an unsuspecting test pilot!
Please don't make the mistake of thinking that trim tabs only are capable of very mild and benign pressures and effect!
Rodger Rinker - Rocky Mountain House, Alberta, Canada
Super Stol build/January 2014
NL7AL & VE6RWR
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Re: electric trim tab actuator

Postby Trilander Ted » Tue Feb 19, 2013 7:42 pm

I like the stock Highlander trim control location, yes, it's difficult to see it's setting, but I got the "feel" of it soon. The prroblem arose when I started teach others to fly. ( I'm not an instructor) I needed a way know if the friend/student had repositioned the trim on touch & gos. Highlanders don't need much trim adjustment anyhow, so I wasn't concened. Then, Gil Tucker put a Ray Allen power trim on after his stock cable broke IN FLIGHT. I just loved his position indicator on the panel, so I sent for the seperate indicator & control from Ray Allen and mounted the "sender" in the control mixer aera in front of the stock trim adjuster and conected it with clevices I got from the R/C model airplane store. My stock lever is almost 35 degres in neutral, and it "feels" good, ( I love it ) and there is no question about trim. I installed a switch to dim it for night flight, as it is very bright. ( I don't fly night any more ) I'm now installing a low fuel warning system sold by HIGHWINGLLC whitch works with the headder tank, it's got to be better than the sight gauge that always turns dark!!.........Trilander Ted
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Re: electric trim tab actuator

Postby FredHoffman » Mon Nov 11, 2013 3:42 pm

Well I too have decided to install the Ray Allen trim servo. The trim tab bell crank is an issue for me as well. I have whittled away quite a bit with a file to make the Ray Allen clevis work. Forget the original hole it is too big and not close enough to the edge to get it to work. In fact in order to get it close enough to the edge to work that hole is only going to be slightly more that 1 hole diameter from the edge. What I did was cut off the bell crank at the bottom of the stock hole then put the clevis against the edge and marked the hole. Then I drilled the hole and removed material on the bell crank to get the range of motion needed. I am not sure I like the result. There is no way it is as strong as it was before, but is it strong enough?

I am thinking of getting a thicker .125" piece of 4130 and making another bell crank, grinding off the old one and welding on the thicker one. I could also have a slightly longer arm as well.

Any thoughts?

Thanks,

Fred
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Re: electric trim tab actuator

Postby Gil T » Mon Nov 11, 2013 5:25 pm

Fred

I posted on this thread on 4-25 and 5-12 on 2012 about my install of the Ray Allen trim system with pictures. Unless the design of the trim system has been changed, with a little bit of filing on the tab arm the clevis will fit just fine. The pictures I posted are with full nose down and with full nose up trim. I just went out to my plane and did a full check and it goes the full limit just fine. There is more than ample trim for any situation that I can imagine.

Good luck.

Gil T
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Re: electric trim tab actuator

Postby SheepdogRD » Mon Nov 11, 2013 5:45 pm

FredHoffman wrote:... but is it strong enough?

It appears that you've left plenty of "meat" there. I've never read or heard about anyone reporting a problem with the bellcrank -- even the modified ones.
Richard Holtz
Highlander N7340Z -- Ms. Tonka -- in gestation

If just enough is really good, then too much ought to be perfect.
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Re: electric trim tab actuator

Postby FredHoffman » Mon Nov 11, 2013 7:59 pm

Gil,

I looked to your trim tab install for ideas and figured I would drill below the stock hole as you did. It did not look like there was enough room above to drill on my trim tab. I was surprised at how much material I had to remove to get the clevis to rotate to the elevator side.

Sounds like you are happy with the way yours works. Mine will have similar geometry.

I will weld on a washer around the hole like Just does on the ailerons and flaps, and leave it like that.

Thanks,

Fred
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Re: electric trim tab actuator

Postby SheepdogRD » Sat Nov 16, 2013 1:17 pm

Questions for those who've installed electric trim:

Did you install a fabric plate to support the fairing?

What sort of fasteners did you choose to attach the servo to the elevator?

Thanks . . .
Richard Holtz
Highlander N7340Z -- Ms. Tonka -- in gestation

If just enough is really good, then too much ought to be perfect.
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Re: electric trim tab actuator

Postby levyland » Sat Nov 16, 2013 2:31 pm

Howdy, I think my airplane is the only SS flying with a Ray Allen trim. I used their grip stick ( I like plug and play) and the indicator is in the Dynon Skyview so it is easy to see. The whole system works well. Jak elected to use the normal pitch trim lever for the locking Pekola tail wheel which works well too. For what it is worth sports fans,,,,,,,,,,,,,
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Re: electric trim tab actuator

Postby FredHoffman » Mon Nov 18, 2013 11:06 pm

Any pictures of the Superstol's factory installed Ray Allen trim system? I would love to see how they did it. Also it would be good know the length they used from the piano hinge center to the clevis pin center. Mine is 1.1" after I cut down the stock arm. I dug around Ray Allen's website and they have a chart for arm length to trim tab range. I came up with 35 degrees up and down on my install, which may or not be too much. ( I suspect too much)

By knowing the optimum trim range of the tab in degrees up and down, the the length of the arm could be set to get that.

Here is a picture of my trim tab arm after a reinforcing washer has been welded on. The washer also spreads the wear out on a greater area of the clevis pin as well.

Fred
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Re: electric trim tab actuator

Postby Dave Krall CFII SEL SES » Mon Nov 25, 2013 8:50 pm

Just to restate in another way for those few who miss the concept, the well known and widely documented fact that just because something "works", or "is working" on any aircraft, does not mean it will stand the test of thousands of hours of air time, particularly if it is a new method or installed to perform under more demanding airworthiness/seaworthiness conditions.
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Re: electric trim tab actuator

Postby danerazz » Tue Nov 26, 2013 11:22 am

...and these are experimental aircraft, and a bunch of the fun is making educated and thoughtful modifications and changes. Sometimes they work, sometimes they don't. That is where the "educated" comes in.
Dane

Paralysis by analysis
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Re: electric trim tab actuator

Postby FredHoffman » Tue Nov 26, 2013 11:35 am

I agree, unfortunately in order to put electric trim in something had to change.

I flew a trip at work with an engineer yesterday, who luck has it designed and built an airplane from scratch. He helped me calculate the expected loads on the parts of the trim system. Everything was assumed worse case scenario and I feel a lot more comfortable about it now.

Fred
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Re: electric trim tab actuator

Postby ransomrocket994 » Tue Feb 24, 2015 12:32 am

I put a Ray Allen electric trim on my plane. I used the T2-10A (1" Travel). With a little modification to the tabs the factory welds on, I added a plate and bolted the servo on. I have full travel with the 1" throw. To cover all of this up, I made an aluminum mold in layers, then glassed the edges in to get what I was looking for. Layed some glass over the mold and it was done. Pretty happy with the way that everything turned out!
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Re: electric trim tab actuator

Postby Familyflyer » Tue Feb 24, 2015 11:56 am

I really like how solid my electric trim is. I hardly move the trim from cruise to landing approaches though.
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Re: electric trim tab actuator

Postby Jack L » Tue Feb 24, 2015 2:29 pm

Familyflyer wrote:I really like how solid my electric trim is. I hardly move the trim from cruise to landing approaches though.


I agree Troy, once I set my trim to neutral for take off I don't touch it unless I am going cross country. The little force felt on the elevator during approach and landing isn't worth the effort of re-trimming. I installed mine in the same way that Steve Dentz did and would do it the same way next time.

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