Rudder spring help!

[markserbu]

As I was taxiing my RV-8A recently, I felt something snap in the rudder pedals and then was suddenly at full right rudder. I parked and shut down the plane, and upon inspection found the pictured spring. I looked over the build plans for the plane and saw no mention of this spring, nor could I find it on Van's site! I've made a lot of springs from music wire over the years, so I figured I'd just do the same for this one. Well, I've never dealt with wire of this diameter (.100"), and it's pretty serious stuff! Just wrapping it around a rod in the lathe and holding it in my hands won't work for this wire...I'd have to make some custom parts to deal with it effectively. Before I go off the deep end and do that, I figured I'd ask here. Does anyone know of a part number or source for these? McMaster-Carr has something very close to this, but I'd rather not guess if I don't have to. Thanks!

 

[Tdeman]

Mark, I'd consider a factory spring setup over replacing these with the same part. The factory rudder springs use two hooks to capture a compression spring. This is to prevent failure modes that tension springs have (such as unlimited strain which can lead to failure.)

The VA-105 is available on the Van's site.

VA-105A

store.vansaircraft.com

 

[rvbuilder2002]

Mark, I'd consider a factory spring setup over replacing these with the same part. The factory rudder springs use two hooks to capture a compression spring. This is to prevent failure modes that tension springs have (such as unlimited strain which can lead to failure.)

The VA-105 is available on the Van's site.

VA-105A

store.vansaircraft.com

The OP post says 8A so no tail wheel steering springs.

That spring that broke is not standard on an 8A, which is why you didn’t find it in the plans. Not sure why someone would have ever installed it.

 

[sf3543]

As I was taxiing my RV-8A recently, I felt something snap in the rudder pedals and then was suddenly at full right rudder. I parked and shut down the plane, and upon inspection found the pictured spring. I looked over the build plans for the plane and saw no mention of this spring, nor could I find it on Van's site! I've made a lot of springs from music wire over the years, so I figured I'd just do the same for this one. Well, I've never dealt with wire of this diameter (.100"), and it's pretty serious stuff! Just wrapping it around a rod in the lathe and holding it in my hands won't work for this wire...I'd have to make some custom parts to deal with it effectively. Before I go off the deep end and do that, I figured I'd ask here. Does anyone know of a part number or source for these? McMaster-Carr has something very close to this, but I'd rather not guess if I don't have to. Thanks!View attachment 58396

Since this an 8A there aren’t any tail wheel springs as previously suggested.
im guessing the original builder installed rudder pedal return springs on each pedal to keep the rudder cables taut.
if so you can just remove the other spring since they aren’t really needed.

 

[Taltruda]

Mark, I'd consider a factory spring setup over replacing these with the same part. The factory rudder springs use two hooks to capture a compression spring. This is to prevent failure modes that tension springs have (such as unlimited strain which can lead to failure.)

The VA-105 is available on the Van's site.

VA-105A

store.vansaircraft.com

Those are the Tailwheel springs.. Mark has a “A” model.. the A model doesn’t use any rudder return springs.. take off the existing one and call it good.. some people feel there’s something wrong because the rudder cables are slack, but that’s what they do.. those look like Cessna style rudder return springs.. throw them in the trash. Just remember whenever you park, try not to park with a tailwind.. the rudder will bang.. also make a rudder lock pin you can put in the rudder stops, or use the Antisplat gust lock off you can get it to be secure.. or the Air Gizmos and you clamp the rudder horn.. otherwise you risk puncture damage from the rudder hitting the elevators.. the rudder return springs probably kept it somewhat centered.. as does a Tailwheel version with the wheel locked straight..

 

[Tdeman]

Oops, read right over the “A” in the original post. My apologies! Don’t do what I said!

 

[Roadjunkie1]

As I was taxiing my RV-8A recently, I felt something snap in the rudder pedals and then was suddenly at full right rudder. I parked and shut down the plane, and upon inspection found the pictured spring. I looked over the build plans for the plane and saw no mention of this spring, nor could I find it on Van's site! I've made a lot of springs from music wire over the years, so I figured I'd just do the same for this one. Well, I've never dealt with wire of this diameter (.100"), and it's pretty serious stuff! Just wrapping it around a rod in the lathe and holding it in my hands won't work for this wire...I'd have to make some custom parts to deal with it effectively. Before I go off the deep end and do that, I figured I'd ask here. Does anyone know of a part number or source for these? McMaster-Carr has something very close to this, but I'd rather not guess if I don't have to. Thanks!View attachment 58396

I believe I have had to deal with this type of spring when changing out drum brakes on a car or truck! They keep the brake pads retracted.... Does NOT look like an airplane part!

 

[AaronG]

Years ago, a number of RV8-A builders were adding these springs to reduce the rudder movement in flight, especially if you take your feet off the pedals. I built to plans and didn’t install them, and never had an issue. Some said the plane is less responsive with the springs. My recommendation would be to remove the other spring and see how you like it.

If you want to replace, suggest you replace both to get the same spring response on both pedals. Getting an exact match of the current springs probably isn’t that important as long as you get the lengths correct. They are just there to dampen the rudder movement.

 

[Roadjunkie1]

Look familiar? These are various springs for drum brakes........... . Really have no place on an airplane.........

 

[Taltruda]

Mark, I think you got the hint that’s it’s not needed to use a spring.. funny thing I was on YouTube and saw the German guy slingshot channel, he made a cap toy, which had me look up the GB-22 video.. where you make springs and bake them in the toaster oven! Funny how the YouTube wormhole comes back around..

 

[gasman]

As I was taxiing my RV-8A recently, I felt something snap in the rudder pedals and then was suddenly at full right rudder. I parked and shut down the plane, and upon inspection found the pictured spring. I looked over the build plans for the plane and saw no mention of this spring, View attachment 58396

Where did you find the spring?.... down by the pedals? Remove the other spring that should be found behind the right pedal.
Inspect the rudder cable installation to confirm it is as Van's instructions. And remove everything that is not on the build plans.

 

[markserbu]

Today I took the good spring off (after just dealing with the huge rudder pedal bias on the last couple of flights) and while it was better than having one spring, I definitely didn't like it as much as having both springs installed. I ordered new springs on McMaster-Carr today and will be installing them ASAP. Yeah the plane doesn't need the springs, there's no reference to them in the build plans, and I hate extension springs in general. But they've been in place for 22 years and I like the feel much better WITH them, so that settles it.

 

[markserbu]

Mark, I think you got the hint that’s it’s not needed to use a spring.. funny thing I was on YouTube and saw the German guy slingshot channel, he made a cap toy, which had me look up the GB-22 video.. where you make springs and bake them in the toaster oven! Funny how the YouTube wormhole comes back around..

I just saw that video the other day! I swear, the GB-22 has been copied more than anything I've ever done! Heck, even his wood copy is a copy of a Russian ripoff of my original design! And yes, that toaster oven has stress-relieved many music wire springs over the years...

 

[Sam Buchanan]

Today I took the good spring off (after just dealing with the huge rudder pedal bias on the last couple of flights) and while it was better than having one spring, I definitely didn't like it as much as having both springs installed. I ordered new springs on McMaster-Carr today and will be installing them ASAP. Yeah the plane doesn't need the springs, there's no reference to them in the build plans, and I hate extension springs in general. But they've been in place for 22 years and I like the feel much better WITH them, so that settles it.

If you flew without springs for awhile, going back to them would make you think you are flying a dump truck.............There are reasons why RVs are renowned for wonderful control harmony.

 

[rvbuilder2002]

If you flew without springs for awhile, going back to them would make you think you are flying a dump truck.............There are reasons why RVs are renowned for wonderful control harmony.

I agree... and the likely scenario if the airplane was built to plans with no springs installed when you bought it, and someone convinced you to install springs... one flight and you probably would have taken them off.

 

[gasman]

That is one mode of failure that I would not want to deal with on a long X/C......... Especially when It can be avoided.

A spring that thick is only there for gust control of the rudder. Make sure it doesn't stack and reduce full travel of the pedal.