RV8 locking tailwheel?

[YellowPeril2]

Hello all,

My father and I have an RV-8 that we have made significant tailwheel modifications on. We had replaced the stock tailwheel springs with one singular two way spring, which makes the airplane much more controllable on the ground at low speed. We also took our tailwheel fork to a machine shop to have the original tailwheel horizontal travel length widened so the tailwheel would have the same angle of travel as the rudder. These modifications have increased the controllability of the plane at normal taxi speeds drastically. During high speed taxi tests, the tailwheel is no longer as controllable as it is during normal taxiing. The tailwheel will almost caster at high speeds and there is some lag between rudder input and tailwheel movement. Is there any reason we can't devise a locking tailwheel for our plane, or has it already been done by other RV-8 pilots? Thanks.

 

[RV8iator]

Reinventing the wheel..

It is EXPERIMENTAL aviation, but if I can ask, why reinvent the wheel? The 8 is one of the most docile conventional gear planes out there.

As for a locking TW, never seen one on a small plane.

 

[jbDC9]

It is EXPERIMENTAL aviation, but if I can ask, why reinvent the wheel? The 8 is one of the most docile conventional gear planes out there.

Agreed. As I read the OP’s list of mods I wondered, “why?”. A solution in search of a problem? My -8 is pretty stock in that I have the Bell fork, lightweight wheel, Tail Lynx steering cables. No handling issues that need fixing.

Could it be needing something as simple as cleaning/lubing the steering lock pin to fix things?

 

[RV8JD]

Personally, I would go back to unmodified parts. The Bell tailwheel fork (fits Van's existing yoke) and the JD Air Parts bearing yoke and fork are very good, and offer more ground clearance than the stock Van's tailwheel fork.

As mentioned above, your original tailwheel assembly may just need some TLC. Below is a link to Dan Horton's tailwheel maintenance document published in KitPlanes:

https://www.kitplanes.com/tech-tip-tailwheel-tune-up/​

In addition to Van's, FlyBoy Accessories and JD Air Parts also carry replacement tailwheel parts. You may want to replace the locking pin, spring, and steering arm (if the notch is worn) in any event.


Here is another recent thread on RV-8 tailwheel questions with lots of good info:

https://vansairforce.net/community/showthread.php?p=1704948​

So there is no confusion with nomenclature:

 

[Taltruda]

I love the JD Air tailwheel setup with the light weight wheel and standard dual chains. If you are having tailwheel controllability issues, your best investment is some dual instruction in various other tailwheel planes. Only AFTER you master the art of tailwheel should you even consider the fancy single sided, or special tailwheel setups. Those special ones sometimes aren’t as robust as the standard dual chain setups, and if you think there’s some locking tailwheel that’s going to make you a better pilot and tame the airplane, then you will be in for a ride when that special “tricked out” tailwheel goes to free caster mode and isn’t there to save you.

 

[fixnflyguy]

Regress to the basic non-full swivel TW

Not sure if the OP is trying to optimize or come up with a tailwheel that doesn't break over easily ?, or what level of TW experience they have...but, in my opinion, minus the inability to push the plane backwards, the standard non-full swivel original TW is as simple and "surprise free" as they get. I still operate my -4 with it after 12 years of flying it, and it gets no more honest and controllable than that simple TW.

 

[JDeanda]

Haigh

Once upon a time some of the akro airplanes sported about with Haigh tailwheels. Either full swivel or locked straight ahead with a couple degrees of steering freedom. No connexion to the rudder. Not sure where you’d find one these days. I taxiied a few, only flew one once and kind of liked it.

 

[Ed_Wischmeyer]

At low speeds, you want a lot of tailwheel deflection. At higher speeds, only a little bit, ad the rudder does the work. What chains do is allow you to have some rudder deflection before you get any tailwheel deflection.

As you're discovering, too much tailwheel deflection at speed is problematic.

 

[oaklandaviator]

Loose springs

Standard Vans tailwheel with really loose springs is about as docile and predictable as they come. And super simple. Works better than the Rocket Link although that’s what I’ve got now. Makes crosswinds a breeze.

Really, just go stock and loosen the chains a lot. Works great just steers at slow speed like an old Ford Fairlane.

 

[RV8JD]

Speaking of Chains ...

As for the amount of slack in the chains, Van's recommends 1/2" of slack:

It should be adjusted such that the tailwheel does not unlock under full rudder deflection, but needs a nudge of brake to unlock it.