What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Rudder Trim

Bill.Peyton

Well Known Member
I noticed that Geoff Combs has photos of him installing a rudder trim servo and tab on his aircraft. Has anyone else done this, or does anyone know of the manufacturer of a such a system?
Bill
 
Do a search on Vic Syracuse's rudder trim. Then roll it out yourself. It would be easier to do while building but we added it afterwards OK.

The ten without rudder trim is not as good as it could be.
 
Phil, et al
This is what I am trying to duplicate.

http://combsfamily.phanfare.com/3161550_3455958
3161550_3455958
 
OK Folks

You can go the trim servo option........if you want to.

But you will se it once or maybe twice a year ..................

Buy this its way easier and less electrics. And trust me electric gizmos are always top of my list, but Rudder is never one of them. :)

BUY THIS>>>>>>>>>

YOU WILL FIND IT IS EASY AND LESS :)TROUBLE.

http://www.mlblueskunk.com/Rudder_Trim_System.html

And you are a nut case if you do not install these......... read again.........if you do not fit these you are not right in the head! :rolleyes: Seriously once you have these you will wonder why Vans did not include them in every kit they sell.

http://www.mlblueskunk.com/Rudder_pedal_Extensions.html


Do I sound like I am passionate.......... YES....I bet there are plenty who will agree. Except those who went to the trouble to do a servo rudder trim :D
 
David,

What's the height of the control knob under the console? The reason I'm asking is I have a longer console (Aerosport Products) and am concerned about knee clearance.

thanks,

bob
 
Mike,
That's the system I am thinking of. The spring system also looks promising. It looks like the same system they have on the Piper Cherokee's.
Bill
 
I tend to agree with everyone here.

Building a trim tab for the rudder is a major PITA and a good way to waste at least a month (probably more) for the inexperienced builder. It's usually the first spot the rookie builder gets off Vans plans and also their first experience with how much time can be wasted when you're working off the map.

The spring system is much easier, but I don't like the knob at my knees and prefer the weight and cleanness of the servo.

All that being said, I'm planning on flying with my current rudder. However I plan on starting a second one as a rainy day project when I can't fly. That's when I'm going to take my time again and tackle the in-line tab and get it absolutely perfect.

A trim tab sounds so simple on the surface, but there is a lot of time to be wasted there.

If I had it to do again (and I'm not flying), I would build Vans standard rudder to get the project moving. Then I'd build a second with the perfect tab. A second rudder can be built pretty cheap; something like $150ish IIRC.

Phil
 
I have been waiting for a good rudder trim system like the one that attaches to the rudder pedals or somewhere in the tailcone on the rudder cables themselves. I have everything needed to install the mechanical system on the rudder but just don't want to drill into my rudder and deal with the PITA factor that Phil is talking about. I have flown for 4 years now with only two wedges and 95% of the time it is perfect but it would be great to have that little adjustment when needed. The time I need it most is when I run LOP and my TAS drops to the 156-162 kts range. Just a little more rudder is needed.

I have a lower panel and worry about leg clearance as well. I hear about a couple more systems coming out and will wait to see how they work before purchasing one.
 
About the only thing I kept a time record for in the hole build was the rudder trim (integral) as shown on Mike's post. It took me about 80 hrs in a two week period. It looks good and with just over 45 hrs on the hobbs works as designed. We have never run out of trim but are very close to the limit in travel. Mike's photos don't show the side opposite the hinge. On mine I rolled the trim skin so the gap (opposite the hinge) stays the same as the trim is actuated. Getting this gap correct took most of my time, (trial and error).
Ron
 
Has anyone thought of fitting a spring-bias system as on the ailerons? Constructing a mount would be easy. The only problem would be attaching the springs to the cable but you could devise some sort of clamp that should do the trick.
 
We tried that a couple years ago-------on a buddies 10.

Servo driven springs, mounted inside the tunnel, rocker switch for control.

Didnt work at all.

The problem is that the springs must be soft enough to allow the rudder cables to move through their full travel, yet the spring must still be able to exert force to bias the cables.

After trying 3 or 4 different strength, and length of spring, we found that there was no joy:(

As I said, didnt work.
 
For those of you interested in the manual rudder trim and knee clearance, this is what I did to ours.

I made an alloy block to offset the knob and capstan so that it could be raised up behind the panel, and cut a notch in the lower panel flange for the shaft.

We did make a slightly deeper panel to fit all the avionics in the way we wanted it so the panel plate is different to the standard one, and its lower by maybe an inch.

So far not one knee strike recorded! :)

m_IMG_1600.jpg


m_IMG_2208.jpg


m_IMG_1600.jpg


m_IMG_2208.jpg
 
Last edited:
Back to the spring idea. It works on the aileron so I don't see why it wouldn't on the rudder. If the springs are long and well-stretched, they work against eachother and the difference in force due to moving the controls is small. The trim recentres the datum and moves the control surface.

I think the secret is long springs rather than the strength.
 
Back to the spring idea. It works on the aileron so I don't see why it wouldn't on the rudder. If the springs are long and well-stretched, they work against eachother and the difference in force due to moving the controls is small. The trim recentres the datum and moves the control surface.

I think the secret is long springs rather than the strength.

The other option is to use a strong spring against a part of the system that has a short throw, i.e., near the pivot point of the rudder pedals or a bellcrank. One could even add a bellcrank just for this purpose. The total spring mass is the same either way.
 
Last edited:
RV10inOZ (or anyone),
How about a PIREP flying with what I'm guessing is the ML Skunkworks (or something very similar) manual spring bias rudder trim. I really like the simplicity of this manual system (if it works) over a servo and trim tab, particularly with Scott's and other reports that rudder trim appears to be a non-issue (assuming the use a wedge to nail cruise trim like Scott did).
 
Has anyone tried to use an electric motor to drive the Skunk works system?
Should not be too complicated, mine is on order and I will use an electric motor
to actuate that trim system.
 
Great Discussion

I'm enjoying this discussion,,

I too have seen pictures of Geoff Comb's rudder trim - very nice job and work, same with Mike's rudder - nice job, both look great! I also like Scott's thoughts (similiar to mine) that if/or since you rarely use the rudder trim, why bother? PITA?

My 10 just passed AWC inspection 10-30-10 and I want a rudder trim but if I only use the trim 5% of the time,, is it worth the effort??

Kenny Gene
294TC RV7a 590 hrs
484TC RV10 10-30-10 AWC
 
Yes You TOO!!

Mike,

Pictures of your plane scream AWC!! No Problem! Or is it just your cute rudder trim!,, Hey now,,

Kenny Gene
 
PIREP

Ok here we go!

Auburntsts

The ML Skunkworks Rudder trim is what you see in my pics, I thought I had a photo of the installed device but I do not. As you can see we concealed it pretty well.

As for in flight adjustment, well in the last 14 months and 265 hours of flight I think it may have been adjusted maybe 4 times.

Seriously.........it works. And it is simple.

I admire those who have gone to the effort of electric rudder trim, because I am a techno nutter.....but really, a 6-8" tab on the rudder is all you really need. I think the skunkworks trim is excessive. Aileron Trim is mandatory.

Has anyone tried to use an electric motor to drive the Skunk works system?
Should not be too complicated, mine is on order and I will use an electric motor
to actuate that trim system.
N427EF

With all due respect......are you mad :eek: Read the above, consider the weight, the mucking around to get it right, the logistics of mounting it etc. You really need to stop the Geek Race here and focus on good engineering practises, ergonomics of your panel and other items and get the plane built.

I am sorry if I sound a bit harsh folks, but I read so many pages here with folk farting about on some things, which they are entitled to do, but then wonder why it takes them 6 years to build a plane. We did ours in a year, and 3.5 months idle waiting for a container to arrive out of that......and I worked a 5 day week.

So now you can see where I am coming from, if you still want to do the electric trim tab as shown in this thread, go for it. But think about the hours the cost and where that resource is going for what gain.

DB......with flak jacket on for incoming!
icon_box.gif
hiding.gif
 
Hey David,

No problem mate.
Always appreciate people who tell you what they think, too many will tell you what you want to hear.
I have 2 buttons left on my stick and thought I could use them for rudder trim??
Reading your post I might just use it for a red light, annunciating flatulence:Dto my passengers.
 
Who said my name was David :rolleyes: :D

Yep.........better getting it straight down the line!

Reading your post I might just use it for a red light, annunciating flatulenceto my passengers.

Now that needs serious attention!

how many buttons on your stick man? We have trim up/down and left right.........AP disconnect on the top two little antennae buttons. Now I have button envy!
 
I have been reading the post with interest because I want a rudder trim in the 10 im building. I have decided to go with the skunk Works manual trim. Looks simple effective and I do not have to rebuild or alter my already built rudder. I think I will place it on the passenger side and build some kind of bracket that mounts it forward of the brace and a little higher to get it out of the leg area.
 
More photos

Here are some more photos of the rudder trim on my plane.

PA010009.jpg


PB030047.jpg


PB030048.jpg


PB030049.jpg


PB030050.jpg


Will have a report on the effect on flying soon :D
 
10 out of 10

How's the rudder trim working out Mike? I see you up and flying now.

Works well, half ball takes a 3 or 4 second activation of the trim-------probably less than half travel?

You can definitely feel the tail wag with the trim.

Glad I made the mod.
 
Anyone with the "piano wire" style have a comment on how well that approach works? Trying to decide if I want an electric trim and which style. Not a lot of Pireps from people who actually installed the trim.
 
I have an electric rudder trim cut into my rudder as Bill was asking about. It works great. I would do it again. I have my trim switch next to my
china hat trim on my infinity grips. As for which one works better they do the same thing so one is no better than the other. I would say the piano hinge
looks like more of a add on but is also easier to install. As for only using your rudder trim very little I disagree. If you have it you will use it a lot more. There are days that I might use it more than others but I do use it and fine
tune the ball always when in cruise.
FWIW (180 hrs with it)
Geoff
 
Back
Top