DougCronkhite
Active Member
My 8 currently has chains on it.. but the previous owner purchased the RV Rocket steering link and tie-down control arm but never installed it? Any recommendation on either?
I am on the other side of this discussion and prefer the chains. Not only that, I like having my chains a bit loose. This allows the rudder to work before engaging the tailwheel.
A loose chain, link, or cable generally allows the tailwheel to swivel past the release point before the rudder reaches its stop. Bad juju. It should need to stretch a spring to reach the release point, with the rudder on the stop. Easy to check. If necessary, move the forward attach points inboard on the rudder horn to change the ratio. Moving them inboard also makes the tailwheel steer a little less quickly, bringing aero and wheel steering into closer accord.
Chains are fragile. A S-curved link is weak. Cable is bulletproof.
All tailwheel mounting springs twist in torsion as well as bending under load. Steering feel is improved considerably by selecting a tailwheel fork and wheel with a smaller torsion arm.
Dan, the bending force on the rudder horn induced by the arm created with the eyebolt has always bugged me, albeit I’ve never heard of that part bending or cracking. What are your thoughts on this?
Ditto, with one additional note... I love the link for steering on the ground, i'm sure it saves on brake pad wear. That said, I had the locking pin wear on me at one point and before I got to disassembling it and reshaping the tip so it worked again, I got quite used to the free-castering tailwheel. As an adequately competent tailwheel pilot, I considered removing the link entirely and just leaving it free-castering. I only kept it in consideration of reduced brake pad wear while manoeuvering on the ground.Switch from chains to rocket link on my -6. Would never go back.
Terry Jantzi, RV6, was the original designer of the RV/Rocket steering link, around 20 years ago. I did the initial flights with the unit on my rocket and I think that is how it got the "Rocket Link" name.
- links, tight chains, loose chains, cables, full swivel, tail skids..... They all work if you have good fundamental technique.
I have a Rocket Link on my RV-8. First taildragger I have flown without chains. I find it very nice on taxi. However, my tailwheel tends to kick into swivel easier to the right than the left. So on every takeoff and landing, especially with any left crosswind component, I have my right foot up where it can catch the right brake in case the tailwheel comes out of lock and darts left. The first time it happened I had my heels on the floor and a seasoned crop duster in the back seat landing on a dirt strip with a left crosswind. As soon as the tailwheel hit with the crosswind controls it went into full swivel and started heading to the left, faster as I slowed and lost aerodynamic rudder force. I had to wake up and get my right foot up on the brake. No groundloop but embarrassing, especially with a guy in the back seat who could feel it coming a mile away as a helpless passenger.
Understanding the tendancy I have learned to be ready for it, especially with a left crosswind on takeoff or landing. I have even gone so far as to warn my passenger as we line up for takeoff with a left crosswind that they will feel a bit of a dart to the left when the tailwheel kicks loose and I have to kick the brake. This really has nothing to do with the Rocket link but the tailwheel pawl adjustment.
I have also experienced the Rocket link overcenter to reverse steering when ground handling when the mains hit a hangar door rail and the airplane bounced backwards with tension on the link. It required lifting the tail onto a support and forcing the internal spring on the link back overcenter to the original configuration. A very unlikely loading scenario during normal operation but might do the same in a severe groundloop if the airplane starts sliding backwards with pilot frantically pressing the rudder pedal to the floor.
Those are some small nits and I like my link enough to keep it but might change the tailwheel out for a different type like the Screaming Eagle I have on the RV-3B. That shoukd help the swivel kick out tendancy in a left crosswind. A friend has this configuration on his 8 and never experiences the kick out.
Jim
I have the rod link to install......but as someone who is a newby tailwheel pilot, should I put the chains on and get experience before tackling the steering link?
Or is it better to start off right off the bat with the link. For those of you 9 drivers.....what do you have? Are the chains more forgiving?
Hi,
At about 180 hours, my RV8 tailwheel link broke when landing. I ordered a new one from JD Airparts . I am wondering if I could fly safely without any link? Taxiing is not a major issue, but in flight I am not sure of the rudder stability...
Thanks for your opinions
Doug,My 8 currently has chains on it.. but the previous owner purchased the RV Rocket steering link and tie-down control arm but never installed it? Any recommendation on either?
Bruce Eicher linked to the thread I posted where I found out the hard way (although not as hard as it could have been) that with the rocket link, there is an asymmetry in the geometry that causes the wheel to get to the castor release point with less than full rudder in one direction.
Jliltd -- what you describe is exactly the issue. Paul, it is not a wear issue, it is intrinsic to the asymmetrical geometry because the angle from the rudder hinge axis to the point on the rudder horn that drives the link is different than the angle from the attach point on the steering arm to the tailwheel pivot.
As some have noted, it is not too difficult to manage a taildragger with a full castering tail wheel, and I have done that a lot. But what is hard is to have the steering lock let go on you abruptly.
A change in the design of the steering arm so that the angle matches the angle on the rudder horn would prevent this. Would be easy to do if the supplier would step up and just do that.
Until then, I went back to the Tail Lynx, which is a very tidy spring system.
Bruce/Steve,Steve,
In your opinion, does the Tail Lynx system provide a comparable level of positive steering control as the Rocket link?
Steve,
I discussed the geometry issue at length with the rocket link manufacturer several months ago. He's aware of community concerns about the link-steering arm geometry issue but considers it a non-problem, based on his own experience and customer feedback. He was pretty adamant about not doing anything to address it. I pushed it as hard as I could, until it became clear that further discussion was pointless. His anecdotal argument did not allay my own concerns, but it seems the customers are on their own if they want to make the geometry mods proposed here by others.
In your opinion, does the Tail Lynx system provide a comparable level of positive steering control as the Rocket link?
Bruce/Steve,
My biggest issue with the RSL vs Lynx was my "Off Road sturdiness required" on my operational requirements list.
It wasn't the positive feedback of the Rocket Steering but the lack thereof.
In gravel, mud, loose sand or soft turf the Rocket Link would breakout continually during taxi and provide zero positive steering (especially with a hard rubber TW) where the Lynx Cables (or chains) would.
The Lynx system works, well, especially under duress.
V/R
Smokey
PS:Trust me, in 25 years I have provided plenty of duress...
Yep, I also have the Lynx cables on my -4 and I?m installing them on my new -7 build. They?re very robust and work great!!
Mark
It seems it shouldn't be that hard for a competent builder to make a prototype and prove the change would be an improvement.A change in the design of the steering arm so that the angle matches the angle on the rudder horn would prevent this. Would be easy to do if the supplier would step up and just do that.
It seems it shouldn't be that hard for a competent builder to make a prototype and prove the change would be an improvement.
Personally I haven't had a problem with my Rocket Link...
If you guys are referring to the Silver Bullet Link, JD Air was born after getting taken for my money after ordering one. Found out later several others had problems too.
The JD Air link looks much like the Silver Bullet but thats it. It was a clean sheet design with much improved innards. We have sold hundreds of these with very few problems. Keep in mind tail wheel components take a beating back there. If you try to lift the tail with the steering link, it will break.
Many if not most of the failures (about 6 over 10 years) are caused by improper maintenance of the tailwheel assemblies. They need to be cleaned, the locking pin and arm checked and everything regreased on a regular basis. I used to do it every oil change while the oil was draining. About 20 minutes start to finish.
Definitely don't be afraid of a steering link type system. It is positive and will give you years of service with proper maintenance. We have them in stock and ready to ship.
If you guys are referring to the Silver Bullet Link, JD Air was born after getting taken for my money after ordering one. Found out later several others had problems too.
The JD Air link looks much like the Silver Bullet but thats it. It was a clean sheet design with much improved innards. We have sold hundreds of these with very few problems. Keep in mind tail wheel components take a beating back there. If you try to lift the tail with the steering link, it will break.
Many if not most of the failures (about 6 over 10 years) are caused by improper maintenance of the tailwheel assemblies. They need to be cleaned, the locking pin and arm checked and everything regreased on a regular basis. I used to do it every oil change while the oil was draining. About 20 minutes start to finish.
Definitely don't be afraid of a steering link type system. It is positive and will give you years of service with proper maintenance. We have them in stock and ready to ship.
Dan,
Did you make up your own cables?
Darwin, I would be delighted to work with you on a modified steering arm geometry, and an accompanying longer link.
I am curious. Is the Rocket or other type of asymmetric push/pull single rod system ever been used on any other tailwheel aircraft or is this just an RV developement?
I have never seen any other tailwheel aircraft with a single rod...
Steve Wittman used a single arm unit decades before there were any RV's. Many of the early Tailwinds and racers were so equipped.
These were solid rods and the tailwheels had no swivel function, but I think your point is the asymmetric actuation, which these share.