sglynn

sglynn

Well Known Member
Do I need aileron trim on a 7A? I will be installing auto pilot servo. My experience with roll trim is in my cherokee which has a rudder trim or you adjust a flap. It doesn't have any aileron trim.

How does the manual spring system work from Van's for aileron trim? Seems to me you have to put the stick where it needs to be for straight and level flight, and if stick isn't centered you make adjustments on ailerons and flaps. So what does the spring aileron trim system do?

Is the spring trim system compatible with an auto pilot servo on the aileron?

I pick up fuselage kit this weekend and need to decide if I should pick up the aileron trim kit also.

thanks
 
IMHO, Yes.........

The manual aileron trim is such a simple system, and it works so well, that IMHO it would be a mistake to not install it.

No matter how well-built your plane, you will always have one heavy wing due to fuel burn, and the trim keeps you from having to hold a wing up. (Or down :p) And you won't be flying all the time with the autopilot on.

$0.02 - Ca-Ching!
 
Yes it works is compatible with AP but it isn't needed

I installed the simple spring system on my RV-6A when I built the plane and it works well. After flying for over a year I installed a Tru Trak autopilot and there is no interference. I NEVER use it. I wish I had rudder trim and some day I will.

Bob Axsom
 
ditto

Bob Axsom said:
I installed the simple spring system on my RV-6A when I built the plane and it works well. After flying for over a year I installed a Tru Trak autopilot and there is no interference. I NEVER use it. I wish I had rudder trim and some day I will.

Bob Axsom
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I never even adjusted it to have the tension it needs. I never use it. Waste of effort in my case ,too.
 
works for me

I use it. No problem with my Trio auto pilot. I have a slightly heavy wing and the trim easily compensates for that.
 
I'm not gonna be much help but... fwiw

sglynn said:
How does the manual spring system work from Van's for aileron trim? Seems to me you have to put the stick where it needs to be for straight and level flight, and if stick isn't centered you make adjustments on ailerons and flaps. So what does the spring aileron trim system do?

Is the spring trim system compatible with an auto pilot servo on the aileron?
thanks
Click to expand...

It consists of a delrin block, springs and lever assembly. It is easy to install and the tension on the springs and drag on the lever's shaft is adjustable. It works fine. Is it necessary... I personally don't think so if you have an A/P. I do use it when I'm flying alone to help balance the fuel load, but the auto pilot would likely handle it just fine. It is likely one of those personal taste things. I don't know if I'd re-install it if I had it to do over again or not. It does come in handy for those flights where you just want to go up and cruise around and have fun without really going anywhere in particular and want to just hand fly the airplane.
 
My -6A is fitted with electric aileron trim and does not have an autopilot. Even if it had an autopilot, it would be used only a percentage of the time. Unlike the experience of some other builders, I very much prefer and use roll trim quite frequently. I like to fly with the joystick oriented perfectly upright at all times. I have found that as little as four gallons fuel imbalance or a passenger will cause the stick to otherwise favor one side or the other. With a flick of the "China Hat" atop the joystick grip, problem solved. Sure, roll trim (or rudder trim for that matter) is not strictly necessary for safe flight but then, neither are air vents. The question we must ask ourselves is "What price convenience?"
 
Rick6a said:
My -6A is fitted with electric aileron trim and does not have an autopilot. Even if it had an autopilot, it would be used only a percentage of the time. Unlike the experience of some other builders, I very much prefer and use roll trim quite frequently. I like to fly with the joystick oriented perfectly upright at all times. I have found that as little as four gallons fuel imbalance or a passenger will cause the stick to otherwise favor one side or the other. With a flick of the "China Hat" atop the joystick grip, problem solved. Sure, roll trim (or rudder trim for that matter) is not strictly necessary for safe flight but then, neither are air vents. The question we must ask ourselves is "What price convenience?"
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Rick----------- I agree! :)

My 6A is equipped with the servo controlled model in the aileron, that was used more often on older models. I'd even prefer it over bias spring setups. But the point is; I like a perfectly trimmed airplane -------without an auto-pilot constantly compensating by putting slight pressures on it's servo motor.
Even with auto-pilots', I'll often turn them off, to make sure the plane is still in trim. And yes, for my small tail 6A, I wouldn't mind a rudder trim too!

I don't believe it's the auto-pilot's place to compensate for an out of trim aircraft --------- because it shouldn't have too. The flying surfaces should remain in trim on their own --- period! I also have the trim buttons on my joystick hat switch. Very convenient.


L.Adamson --- RV6A
 
Really?

L.Adamson said:
Rick----------- I agree! :)

I don't believe it's the auto-pilot's place to compensate for an out of trim aircraft --------- because it shouldn't have too. The flying surfaces should remain in trim on their own --- period!
L.Adamson --- RV6A
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I agree that you should trim your airplane before activating your autopilot, but my AutoPilot does not know the difference. I asked it and it told me that it did not care...:D
(autopilots dont know what position your control surfaces are)
When I set my autopilot, I set and forget. I dont shut it off mid trip and retrim. Maybe I should.
 
Is it your left wing, or right?

andrew phillips said:
I use it. No problem with my Trio auto pilot. I have a slightly heavy wing and the trim easily compensates for that.
Click to expand...

If it is you left wing, your probably dont have a heavy wing, it is just that you sit on the left. My airplane is perfectly in trim when I have a passenger of similar weight to myself. If I am solo, I have a heavy left wing. Perfect.

I do not have Aileron trim due to how I did my Autopilot install. I get along just fine without it. I also rarely use my Autopilot.
 
Here's a couple of pics for ya for a visual...manual version.

11-7-07-003w.jpg


11-7-07-005w.jpg


11-8-07-001w.jpg
 
I like my manual trim and use it often. Whether you install manual or electric trim I used very short SS fishing line leads to connect the trim lever to the springs. These worked great over the safety wire method and ensured equal bias on the springs.
 
thanks I've added electric aileron trim to my fuselage order

Thanks, much appreciated. I just added electric aileron trim to my fuselage order and will pick it up Monday. thanks

PS, Now I gotta go look at retro-fitting electric elevator trim. It would be nice to have both roll and pitch electric on the stick. Any comments on installing electric servo for elevator trim tab after the fact? Looks like only minimal rework and only a few drill outs.

thanks
 
Go fly both first

sglynn said:
Thanks, much appreciated. I just added electric aileron trim to my fuselage order and will pick it up Monday. thanks

PS, Now I gotta go look at retro-fitting electric elevator trim. It would be nice to have both roll and pitch electric on the stick. Any comments on installing electric servo for elevator trim tab after the fact? Looks like only minimal rework and only a few drill outs.

thanks
Click to expand...

I would strongly recommend you try to get a little stick time in both manual and electric trim set ups. There are certainly two distinct camps. Lots of threads on manual vs electric also so dont want to start it all over again here.
Cant answer your question directly but I am sure someone here can tell you what might be involved.
 
aileron trim

Instead of adding safty wire or fishing line inorder to get the right spring length, why not go down to the hardware store and buy a proper length spring?
 
JonJay, great advice. My 1979 cherokee Dakota has both electric trim and manual trim for pitch on the stabalator. So I have experience with both. Problem is on a 30 year old airplane the electric trim mechansim has a clutch that is worn and doesn't work so great, but it does. The cherokee has the manual trim wheel between the seats, and I use it, but with a co-pilot it is a bit of a pain to reach in there because it makes the co-pilot lean over out of the way. I'm thinking the RV-7 is newer, lighter, and more nimble than my 2500 pound Cherokee and so I'm anticipating electric trim to work better than my current one. And I do appreciate removing mechanical knobs as much as possible to make room for people.
 
sglynn said:
Thanks, much appreciated. I just added electric aileron trim to my fuselage order and will pick it up Monday. thanks

PS, Now I gotta go look at retro-fitting electric elevator trim. It would be nice to have both roll and pitch electric on the stick. Any comments on installing electric servo for elevator trim tab after the fact? Looks like only minimal rework and only a few drill outs.

thanks
Click to expand...


Go with manual trim on both aileron and elevator. Completely trouble free and very precise. I have flown a dozen RVs about half with electric trim so I have a lot of experience with both. Also you will have over a 50% chance of having problems with the electric trim. My friend is retrofitting his 8 with manual trim after flying 3 years with electric. KISS is best. Don
 
Aileron Trim

I have manual trim & use it all the time. I would not be without it.

Dick DeCramer
Northfield, MN
RV6 N500DD 300 hrs.
 
In regards to elec. versus manual trim. In my 6A, the electric aileron and elevator trim has been excellent. I don't have speed controllers either. Yet, other pilots who have flown my plane have remarked how well it trims out.
My aileron trim is the outboard servo controlled tab on the aileron.

I always prefered yoke controlled trims in the Pipers, and I haven't changed my mind in regards to an RV. Both trims are on my joystick. Of course, others have different opinions.

L.Adamson --- RV6A
 
"Can't we all just get along?"

L.Adamson said:
......In my 6A, the electric aileron and elevator trim has been excellent....other pilots who have flown my plane have remarked how well it trims out....always prefered yoke controlled trims.... Both trims are on my joystick. Of course, others have different opinions. L.Adamson --- RV6A
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We must be on a roll Larry. Both of us are in complete agreement for the second time now. :)

6p3gud.jpg
 
L.Adamson said:
My aileron trim is the outboard servo controlled tab on the aileron.

L.Adamson --- RV6A
Click to expand...

In that case, do you need two servos(One for each wing)? Will just using one put different load on the ailerons? If two are used, how do you synchronize them?
 
Aviator168 said:
In that case, do you need two servos(One for each wing)? Will just using one put different load on the ailerons? If two are used, how do you synchronize them?
Click to expand...

Just one servo & tab, since the ailerons are interconnected. As in Rick's pic; his is on the left, and mine is on the right to offset my fat... :)

L.Adamson --- RV6A
 
Rick6a said:
We must be on a roll Larry. Both of us are in complete agreement for the second time now. :)

6p3gud.jpg
Click to expand...

That's amazing! And I even have the star on my left wing too! Just think, once your RV8 is flying.......................perhaps we'll agree THREE times! :D

L.Adamson
 
Trim Servos and AP Servos

Looks like I will be using Van's Aileron electric trim for 7A which is a servo under the seat that adjusts the springs to balance stick forces rather than using an actual trim tab on the aileron. So no aileron trim tab. Just load balancing springs. This seems logical because the purpose of trim is to relieve stick forces, not to fly the airplane. And then I'll have an autopilot roll servo in the right wing, at the bell crank, which moves both ailerons for flying the airplane. Same is true in the empennage. There is a small electric servo to move the elevator trim tab for relieving stick pressure for a given, climb, descent, or level flight, and then a larger servo that moves the elevator for the autopilot to fly the airplane.

Summary: 4 servos. 2 for trim 2 for flying. One tab on elevator. No tab on ailerons.
 
Using load balancing springs for trim is not exactly the same as directly control the trim tab on aileron even though it may feel the same for the pilot. The difference is in the aileron control rod or cable. With trim tabs, the load on the rod/cable is absolutely nothing. Not the same thing can be said about balancing springs.
 
Adding a "built in" trim tab

The RV's have very nice light ailerons, so I wanted a purely aerodynamic tab to do the trimming: no springs added to the pure natural aerodynamic feel. So I designed a trim tab for my RV4 that was "built in" to the aileron.

Predicted hinge moment for the aileron was low, so the tab could be small. It consisted of a tab on the inboard end of the left aileron. The tab was only 4" long with a chord of 1". Deflection was done with a MAC servo and limited to 20 deg up/dn.

This design did require some small internal changes to the aileron to mount the servo, and a really short stub-spar for the trim tab. All easy to fab up in house though. It sure worked nice!

Here's a pic of the internals:
Aileron2.jpg
 
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