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prkaye

Well Known Member
I've heard that many builders find the need to add a rudder trim tab after test flights, to straighten-out flying characteristics.
My plane is going to be (professionally) painted prior to first flight (yes, this decision is *finally* finalized), so I'm wondering if I would be wise to fabricate and/or install a rudder trim tab now that I could bend into place as-needed after test flying. This would save me taking another part back to the painter after test flying.
Thoughts?
 
If you built the plane according to the plans you will not need a rudder trim tab.
So far I have not needed one.
 
Phil:

Many, if not most, of the RVs need a trim tab to help. Very normal unless the 9 is somehow different. If you use the Avery trim tab (which is 6 inch long wedge of some sort of composite material) you can have your paint shop paint it separately while they are painting the rudder so the colors will match. Afterwards you can tape this in place to figure how much of it you really need and just trim the wedge from the bottom up if you need it shorter. Then the only unpainted portion will be the bottom of the wedge which you can probably touch up to match. The final install can be done with something like 3M weather strip glue (the yellow sticky stuff). It will stay on, but can be removed in the future without damaging the paint underneath.

This is what I did on my -8.

Chris
 
Thanks for the simple solution that won't damage the paint

Thanks Chris.

We built our 9A according to the plans but still need a trim tab. My reluctance has been to mess up my paint but your idea of trimming from the bottom and the use of 3M makes a lot of sense.
 
I have friends that have done both (a pre-painted metal tab that will bend and the Avery piece that Chris talks about) and no complaints either way. Chris is right, all the ones I see have some type of trim. One thing you may want to consider..I am with my 12...is that until you have wheel pants on its hard to set anything. So for now I just use my right foot.
 
Thanks.... this is a great solution (the avery trim tab). What sort of tape should be used for the temporary fitting? Something strong enough to hold it but weak enough to pop it off for trimming without damaging the paint underneath....
 
These airplanes are all hand built, even though some are prepunched. Because of that, there will always be minor variations, and some will claim theirs doesn't need a trim tab. The reality is that any airplane will only be at perfect trim for one airpseed and one power setting. Change any of those, as will happen on climbs, decsents, cruise altitudes (yes, IAS will be lower at higher cruise and therefore less airflow over the surfaces), and you will find the need to adjust a control surface. It is also very nice to have the adjustable trim on the rudder for those long descents from the high cruise altitudes. It is also very nice to be able to trim the wings level when the autopilot is engaged thru the use of an adjustable rudder trim. Is it absolutely necessary? No. But it sure is nice to have. :)

Vic
 
I know a number.....

of people who have used Blueskunk trim, seems to work well. I did one similar to his, his I think works better. You can't beat the price or quality.
 
Very Satisfied

Very satisfied with the Skunk Works Rudder trim after have flown for over 130 hours on my RV7A. Had to hold a little right rudder before installed and it is really easy to change the trim with different power sittings. Also another plus is that the springs always have some tension on them so the rudder not as apt to be moving around in the wind sitting on the ramp. I have installed their rudder pedal extensions also very satisfied. Their products are high quality would purchase again if I build again.

Don?Squeak?Schnarr
Jasper, IN
RV7A
 
That looks like an interesting setup that would work at various speeds. I also would like to hear from anyone who has used it. I presume that like the aileron trim (Vans), the trim setting is held by friction?

greg
 
prkaye said:
....What sort of tape should be used for the temporary fitting? ....
Click to expand...

Phil:

I found that a narrow strip of the self-adhesive aluminum heat reflective material you use as a heat shield on the interior of the engine cowl (see Van's 2009 catalog page 16) works really well. It will hold the tab in place but comes off easily without marring the surface or leaving any residue. Just cut a piece large enough to cover the entire tab plus leave about 1/2" to an 1" of material all around to stick to the rudder surface. Align the thick end of the wedge with the trailing edge of the rudder and stick it in place. Exactly where vertically is up to you but somewhere just above the plane of the horizontal stabilizer should be about right. Use one of the horizontal rivet lines on the rudder as a benchmark so that you can easily start in the same place each time you trim the tab.

Chris
 
I made one from balsa wood, started with 6 inches long and about 2.5 wide with the thick part at the back side 3/8 or so . I flew the airplane and trimmed length from the bottom about 1/2 inch at a time until the trim was set ended up with about 4 inches in length . I primed , painted and attached with 3M double side exterior tape over 150 hrs.
 
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