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-   -   Too much slack in tailwheel chains? (https://vansairforce.net/community/showthread.php?t=159679)

donaziza 04-18-2018 09:21 AM

Too much slack in tailwheel chains?
 
There's another post about using or not using flaps in cross wind landings. Let me throw a new wrinkle in this discussion. I "think" I've got too much slack in my tailwheel chains, making it take longer when I hit the rudder pedals for the rudder/tailwheel to react in strong crosswinds. What say the rest of you guys? Do you have your chains really tight, ie, no slack? Slightly loose? Or really loose?

I think I need to take a link or 2 out of my tailwheel chains---but I'd like to get some input first.:o

Mike S 04-18-2018 09:30 AM

Do you have springs in the chains?

In a prior life, I flew a 48 Stinson, when I got it there were no springs in the chains and it was a bear to control. Added springs and took out most of the slack and it tamed the beast.

Compression springs like these are what I used.



I suspect tension type springs are not a good choice.


Mel 04-18-2018 09:38 AM

I agree with Mike. Compression springs minimal slack.

donaziza 04-18-2018 10:01 AM

Yes, I do have springs---like the ones in Mike's first picture.

Ironflight 04-18-2018 10:16 AM

Tight chains vs slack in chains is a religious argument that I believe started between Wilbur and Orville.....I have great friends who are great (and we’ll respected)pilots on both sides of the argument. Both obviously work. Personally, I like tailwheel links, but I fly lots of planes with chains - loose and tight -and I just adapt.

JonJay 04-18-2018 10:20 AM

I refuse to believe that one or the other, slack or not, makes that much difference. However, there have been more than one runway departure caused by "pilot induced" oscillation theorized to be caused by too tight of chains/link. I know of two, both low time pilots who over-controlled per their own admission. One changed his set up (looser) until he got more hours, then went back to the tighter set up (link). A very experienced transition trainer will caution against too tight of chains for a tailwheel newbie for these reasons.
I keep my "chains" on the looser side, but that is just personal preference, and not for any other reason as I do not feel it makes that much of a difference in a cross wind. You should already be slipping to keep the airplane from drifting and your slack should be gone. If your slack isn't gone, it isn't that much of a crosswind to worry about.

rvsxer 04-18-2018 10:45 AM

I still have the old style, non-swiveling tailwheel(!). Tight chains limit rudder travel, even with springs, due to the geometry of the two control horns. I'd rather have the rudder so my chains are slack. Most Pitts Specials I've seen have a full-swivel locking tailwheel (the Haigh was a good one I'm told) with no link to the rudder. I think if you are down to depending on the tailwheel to stop a groundloop you are already too far gone.

flyinga 04-18-2018 11:11 AM

I too started out with lose chains/springs (stock settup). I didn't like it and switched to the Rocket Link which I like much better. As previously mentioned, I think it's "personal preference."

cajunwings 04-18-2018 11:31 AM

Springs
 
Is there a problem with tension springs?

Don B

Mel 04-18-2018 12:12 PM

Quote:

Originally Posted by cajunwings (Post 1253938)
Is there a problem with tension springs?
Don B

Tension springs are fine up to a point. Compression springs have a limiting factor in that they stop when completely compressed. Tension springs don't have that feature, so they can continue to stretch until they eventually loose a portion of their tension.

DanH 04-18-2018 12:54 PM

Slack means most tailwheels, if forced sideways, will pop into full swivel. You're allowing the tailwheel fork to swivel farther than the rudder.

Easy test...position your airplane with full rudder applied, rudder horn against the stops. Now push the tail sideways. If it is easy to push into full swivel, or is already released, the slack chains are allowing the fork to turn too far. We want a system which requires a brake tap to force into full swivel.

If tight chains (or a link) is causing the steering to be too quick, the arm ratio is wrong. Simply move the chains or link inboard on the rudder horn, or move them outboard on the fork arm. it will probably fix the aforementioned release angle problem too.

rvbuilder2002 04-18-2018 01:26 PM

Quote:

Originally Posted by DanH (Post 1253965)
Slack means most tailwheels, if forced sideways, will pop into full swivel. You're allowing the tailwheel fork to swivel farther than the rudder.

Easy test...position your airplane with full rudder applied, rudder horn against the stops. Now push the tail sideways. If it is easy to push into full swivel, or is already released, the slack chains are allowing the fork to turn too far. We want a system which requires a brake tap to force into full swivel.

If tight chains (or a link) is causing the steering to be too quick, the arm ratio is wrong. Simply move the chains or link inboard on the rudder horn, or move them outboard on the fork arm. it will probably fix the aforementioned release angle problem too.

I agree with Dan but I believe that too tight can induce the same problem in (unintended unlock of the tail wheel) some cases.

When the airplane is traveling fwd with the tail wheel on the ground, it has a natural castor tendency to straighten out and align with the direction of travel. This will actually be countering any looseness in the chains and not allow the assembly to move far enough to unlock.
There have been instances where very tight chains are able to rotate the tail wheel far enough to unlock because the rudder is able to over come the natural castor force. This is particularly common with some installations of the single steering link because it doesn't cause an equal amount of tail wheel steering angle in both directions.
I know of one ground loop accident that I believe was cause because the tail wheel unlocked with full rudder input, with a steering link installed.

donaziza 04-18-2018 01:30 PM

Quote:

Originally Posted by DanH (Post 1253965)
Slack means most tailwheels, if forced sideways, will pop into full swivel. You're allowing the tailwheel fork to swivel farther than the rudder.

Easy test...position your airplane with full rudder applied, rudder horn against the stops. Now push the tail sideways. If it is easy to push into full swivel, or is already released, the slack chains are allowing the fork to turn too far. We want a system which requires a brake tap to force into full swivel.

If tight chains (or a link) is causing the steering to be too quick, the arm ratio is wrong. Simply move the chains or link inboard on the rudder horn, or move them outboard on the fork arm. it will probably fix the aforementioned release angle problem too.


Thanx Dan, I like your answer. I have a "lot" of slack in my chains, so your first answer is easy to do. Your 2ed answer, "if chains too tight", I wasn't a builder or mechanic, so I don't understand, but I "do" have a mechanic, and I'm sure he will understand.

DanH 04-18-2018 02:06 PM

Quote:

Originally Posted by rvbuilder2002 (Post 1253973)
I agree with Dan but I believe that too tight can induce the same problem in (unintended unlock of the tail wheel) some cases.

Agree...if the arm ratio is wrong.

It can't unlock if it doesn't reach the release angle.

Mike S 04-18-2018 02:10 PM

Quote:

Originally Posted by DanH (Post 1253984)

It can't unlock if it doesn't reach the release angle.

That is for a correctly installed, maintained and functioning unit. These things do require maintenance.

Jpm757 04-18-2018 04:43 PM

I have always kept positive tension on all of my tailwheel springs, I think it reduces wear and allows for more precise control. I installed the Flyboys Rocket Link on my new -7 and I love it! My buddy put one on his -8 and he too is sold. Only 100 hrs since new, we'll see how it holds up.

RV6_flyer 04-18-2018 08:16 PM

Quote:

Originally Posted by Ironflight (Post 1253909)
Tight chains vs slack in chains is a religious argument that I believe started between Wilbur and Orville.....I have great friends who are great (and we?ll respected)pilots on both sides of the argument. Both obviously work. Personally, I like tailwheel links, but I fly lots of planes with chains - loose and tight -and I just adapt.

I have read all the posts in this thread. I agree that there will be a personal preference on how tight or how loose. Yes one gets use to different adjustments in different airplanes or at least Paul and I do.

I found that the chains furnished with the kit stretch and get loose after 300-hours. Taking out one links then makes it too tight for me. New chains work well till they get time on them and then stretch again.

I changed out the chain for cables on the standard "compression" springs and that was over 2,000 hours ago. Have flown other tailwheel airplanes and although not the exact way I like it on my airplane, there was no issue adapting to the difference.

drycreekrv 04-19-2018 06:57 AM

After 25 yrs......
 
It's worth considering....(for tail wheel RV's) --- that little tail wheels are
sensitive to every little bump it runs into. Tight Springs/Cables makes
the rudder sensitive as well. Ever noticed some RV's who rudder wiggles
with every movements the tail wheels feels... almost rattling around all
the time. I've found over the years.... loose chains help with the overall
wear over the years. Iron Flight said it right..... it's easy to adjust.
Replacing a worn out rudder is a lot of work.

dougweil 04-19-2018 01:59 PM

On both my RV-4 and RV-7 I have used Citabria tailwheel springs. I have the chain length set so they are "just" tight (or no slack). I do replace those cheap tailwheels every couple years as I think they steer funny when the rubber gets worn down flat. With this arrangement I feel the steering is positive but not twitchy. I don't care for slack in the chains which creates a "dead" spot in the steering.


Christopher Murphy 04-19-2018 02:11 PM

Make too much of it..
 
Ive flown my rv4 with nothing connecting the tailwheel to the rudder several times..I like my chains loose so the rudder steers until about half deflection before the tailwheel gets pulled by the chains..

Cm

Capt 04-20-2018 04:41 PM

Quote:

Originally Posted by Christopher Murphy (Post 1254210)
Ive flown my rv4 with nothing connecting the tailwheel to the rudder several times..I like my chains loose so the rudder steers until about half deflection before the tailwheel gets pulled by the chains..

Cm

That about sums it up. My 8 has slack compression chains, I like the fact that the rudder is effective first, wheel latter. Together with the brakes all three forms of directional control work just fine👍:)


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