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Elevator trim tab question

Mike S

Mike S

Senior Curmudgeon
For those of you who have actually been flying your 10s, have you noticed any problems with the elevator trim tab setup (asymmetrical travel)when set up as per Vans instructions?

If anyone has made changes, or adjustments, what are you doing??

Or, is this a "non problem" that just simply dosent pass the "TLAR" test??

Anyone who would re-design things while still in the building stage??

Thanks for the input.

Mike
 
David, thanks this is the type of info I am looking for. I was thinking along the same lines as that, for setting the tabs.

Anyone else out there with input, please respond.

Thanks, Mike
 
Trim tab fix

I don't know about all of you 10 builders out there, but am I the only one that can see the obvious problem with thetrim tab set up?

The difference in the trim tab cable travel is simple to fix by attaching the two seperate cables to the trim horn at the same place.

This involves adding an additional horn and moving the center cable over.

Pic's of my fix should be avail. soon.

Staring RV-10 wings
Reddsky1
 
Red sky, yep, I see the same thing when I look at the mechanism-----and the same solution--- mount both cables at the same place both for the housing, and the inner part.

What I was trying to get feedback on is weather there is a problem in actual flight use----------in other words, is this a non problem that fits into the category of "if it aint borke, dont fix it"..

After 40 or so hours, it is looking like it is not a problem in flight-----------just looks like it should be a problem when you look at the setup as you are building it.

Thanks for the input.

Mike
 
elevator trim tab

No problem with asymetrical trim tab travel in mine after flying 40 hrs.

My RV6A only has trim tab on one side and that does not present any problem either. I believe the 7s also has trim tab on one side only.

Son
RV10- N172KT
 
Don't fix a non-existant problem

Reddsky1 said:
I don't know about all of you 10 builders out there, but am I the only one that can see the obvious problem with thetrim tab set up?

The difference in the trim tab cable travel is simple to fix by attaching the two seperate cables to the trim horn at the same place.

This involves adding an additional horn and moving the center cable over.

Pic's of my fix should be avail. soon.

Staring RV-10 wings
Reddsky1
Click to expand...
The travel is supposed to be asymmetrical. Don't go fixing things that don't need to be fixed.
 
elevator trim tab

I seem to remember Bill DeRouchey saying he had discussed the issue with Van's and they have rigged their -10s as he suggests. I believe the tabs were originally engineered so that there would be a flap interconnect that would automatically adjust trim with flap extension and retraction. That idea was abandoned, but the trim actuation set up was not re-designed.
Then again, maybe I dreamed all of this. At my age one cannot be sure! :eek:
 
dmaib said:
I believe the tabs were originally engineered so that there would be a flap interconnect that would automatically adjust trim with flap extension and retraction. That idea was abandoned, but the trim actuation set up was not re-designed.
Click to expand...

I got the same info from Mel Asberry.

As far as I have been able to tell, no matter how goofy the monkey motion looks like, it appears to not be an issue in flight.

Mike
 
Last edited:
Trim tab set up

Hello everyone. My opinion is that the trim tab set up is just fine. I just turned 480 hours on the RV-10 this past week end, and I think during that time I have seen most every kind of loading, speed, and altitude scenario. I have not noticed any issues with the trim at all. That doesn't mean someone hasn't/won't design a better system, as that's what this Experimenting is all about. But, at this point in time, I don't see that there is anything to fix.

Vic
 
I ain't no engineer, but my friends at Rockwell are.

The trim tabs should not be asymetrical in their travel limits.

It may not cause noticable abnormal flying conditions, but it does cause asymetrical stresses to the Horizontal Stab. and elevators.

Take it for what it is worth, my 2 cents. :)

Reddsky1

Building (SB) RV-10 wings
 
Reddsky1 said:
I ain't no engineer, but my friends at Rockwell are.

The trim tabs should not be asymetrical in their travel limits.

It may not cause noticable abnormal flying conditions, but it does cause asymetrical stresses to the Horizontal Stab. and elevators.

Take it for what it is worth, my 2 cents. :)

Reddsky1

Building (SB) RV-10 wings
Click to expand...
If this is the case, then almost all GA airplanes are in trouble, as they almost all have a trim tab on one side only.
 
Elevator trim tabs

I believe the assymetrical stress was what Bill DeRouchey witnessed on his airplane, in flight, when he looked back at the horizontal stab. Makes sense to me.
 
trim travel

I had the oportunity of fly the 10 for a couple of hours,and the first fly things you learn is ,don't touch that trim until you are high ,let me tell you guys ,that trim is very ,VERY sensitive,I beat you don't move more then a 1/4 inch at all,when discuss with Van's ,the reason for the assymetrical travel,and make sense to me ,was,because the 10 is nose heavy,you don't need to much down trim ,but need much more nose up,I purchase the speed reduction from Ray Allen,
And another system I changed after that fly ,was the position for the front air vents,if you are in the 6' tall range ,and you open the front vents,your knees will be very mad with you,they will frezze.
Hugo,#40456
 
Your right it is asymmetric when you are at the complete limit because of the way it is designed. But you never even get close to those limits. You probably will go from ?? up on one side to ?? up on the other side depending on your loading in the aircraft.

It is very sensitive when you are at cruise flight but not too bad. It is just the right speed when you are landing. I have a speed controller but see no reason to install it.
 
Trim tab solution?

Though it doesn't seem to be an issue for most, I had some time on my hands and started looking at the trim rig laying on my bench. Seems like a simple solution, but I wanted to see if anyone could lend an engineering eye to my idea. I built a new cable anchor (1st pic) that allows both to be mounted side by side, which is simple enough. Question 1 is with where the rod ends attach to the bellcrank. Will the 3/16" bolt through both rod ends be adequate for the load? The bolt in the 3rd pic is not correct length, but it shows the attach geometry. Next, might there be leverage issues with having the load from both cables going to the front hole on the bellcrank?

2419oq1.jpg


eg975.jpg


2vxftk9.jpg


Thanks for looking
 
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