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Locking Tailwheel

Eddie, Many of the guys above have WAY more experience than me but I'll share what I've experienced and some of what they haven't covered.

My 185 has the factory float kit which includes some pretty heavy springs on the rudder, heaviest I've ever felt. The larger 185 dorsal and heavy springs contribute to the leg fatigue mentioned earlier, the lock definitely helps but has limitations on where and how. The rudder is near the same sq/in as the cub with near double the HP and only a little more arm, (length of fuselage), add in the torque and p factor and things start to pile up against your will to travel in a straight line. It's not uncommon at the beginning of a short field T/O to end up with the rudder on the floor for a couple of seconds with only a slight x-wnd, might even include a tap of the downwind brake if gusty. Take offs aren't the real problem because the prop slipstream energizes the rudder. Landings are where things get interesting.

It's not that it runs out of rudder prior to touch down, it's when the tail begins to settle during roll out that is the danger zone. I don't know if it's simply the lack of airspeed, or that the rudder comes out of the clean air as some suggest, but its not until that moment that you'll know if you're asking too much of the airplane and the lock isn't any help until the tail is down with some weight on it. Be ready for the go around!

The only con I can think of comes down to my own stupidity. Once I left the t/w locked while trying to exit the runway and pushed the tire off the rim cutting the tube, the tire pressure was around 40psi and she was heavy. I now run nearer 70 psi and pay a lot more attention to it during pre-flight. Pierce's recommendation of the 6 ply tire was a huge help, and I also carry a spare.

I've intentionally sought the x-wnd limits in both airplanes many times. My experience has been that the cub deals with x-wnd better because rudder is much more responsive. By comparison the 185 rudder feels sorta like pedaling a bicycle under water, not only is it much heavier but big inputs don't have as much effect.

Now for the YMMV disclaimer: 78 A185F, factory float kit, IO-550, Robertson STOL, 88" 3 blade black Mac, EW 2098#, mostly on 8.50s. Realize that many of the 180s and 185s are very different animals from one to another.

While I was transitioning I used it most of the time, nowadays only with high x-wnd. For me, the relatively small weight penalty the lock adds is outshined by adding another tool to the bag.
 
My 185 has the factory float kit which includes some pretty heavy springs on the rudder, heaviest I've ever felt. The larger 185 dorsal and heavy springs contribute to the leg fatigue mentioned earlier,..
little wing,
Exactly which springs are you referring to? There are two different sets of springs which connect the rudder bellcranks in the tail to the tail wheel steering and water rudder steering cables. The springs which are used for the water rudders are the "heavy" ones. The springs which are used for the tail wheel steering are the "light" ones. These springs are supposed to be changed when changing between floats and wheels. Are you using the seaplane springs while on wheels?
 
little wing,
Exactly which springs are you referring to? There are two different sets of springs which connect the rudder bellcranks in the tail to the tail wheel steering and water rudder steering cables. The springs which are used for the water rudders are the "heavy" ones. The springs which are used for the tail wheel steering are the "light" ones. These springs are supposed to be changed when changing between floats and wheels. Are you using the seaplane springs while on wheels?

Thanks man, I'm not sure which are in there. Can't remember for certain, but think it was only on skis without ever being on floats. Just for one season in 79, I'll look at the logs tomorrow. I have no idea which springs are installed, just know it pretty darn heavy. Thanks again for trying to help, but if I can trouble you for one more response, what am I looking for on the springs to know if it has the float springs installed, and what do I order if if they are?
 
little wing,
Exactly which springs are you referring to? There are two different sets of springs which connect the rudder bellcranks in the tail to the tail wheel steering and water rudder steering cables. The springs which are used for the water rudders are the "heavy" ones. The springs which are used for the tail wheel steering are the "light" ones. These springs are supposed to be changed when changing between floats and wheels. Are you using the seaplane springs while on wheels?
I took it to mean he was referring to the centering springs mounted to the top of the tailcone near the vertical fin, and not the tailwheel/ water rudder springs on the bellcranks...
 
Thanks man, I'm not sure which are in there. Can't remember for certain, but think it was only on skis without ever being on floats. Just for one season in 79, I'll look at the logs tomorrow. I have no idea which springs are installed, just know it pretty darn heavy. Thanks again for trying to help, but if I can trouble you for one more response, what am I looking for on the springs to know if it has the float springs installed, and what do I order if if they are?
Take off the belly inspection plate which is just ahead of the tail bulkhead. Look aft. The wire on the heavy springs is about 1/8" in diameter. The light springs are about half of that. You should have the other set of springs as they were delivered with the airplane in a big brown envelope.

I took it to mean he was referring to the centering springs mounted to the top of the tailcone near the vertical fin, and not the tailwheel/ water rudder springs on the bellcranks...
I thought of that but they are relatively light and can be adjusted to have very little effect.
 
but think it was only on skis without ever being on floats.
You can determine if it has ever been on floats just by looking at the fuselage ahead and below the lower forward corner of the baggage door. There will be two holes drilled by Cessna with buttons in them. If there are four holes someone put it on floats. The rear float fitting is used as a drilling fixture for the 3rd and 4th holes. This is the same on both sides of the fuselage.
 
I seem to remember removing the factory tail wheel locks on our 185s, when you could still get a factory new 185!
Some pilots had a hard time remembering to unlock the tail wheel and would spin the mains off their wheels trying to turn.
There were quite a few broken main wheel bolts incurred, also.
 
I wonder if that there is finally validation enough to use wheel landings most of the time when heavy!

Using a wheel landing is great, but to paraphrase an old saying: You can’t keep that tail up forever. At some point, that tailwheel is going to come down due to lack of airflow over the horizontal tail surfaces. And if it’s tail heavy, as Mike noted, that’s going to happen sooner, as opposed to later.

I have three pointed a 185 in a significant crosswind while heavy, and used fairly heavy differential braking.....kept that tail solid in contact. But, again, that was a well set up tailwheel. I see a lot of pilots who pay zero attention to tailwheels.....and a few mechanics who pay almost no attention to tailwheels during maintenance.

I was assigned a brand new 185 in 1986, with 25 or so hours on the clock. It came with tailwheel lock, but our maintenance crew had removed the lock. I don’t know what their logic was, but I never really missed the lock in any case.

MTV
 
Yeah, I agree with that, for sure.
I was thinking about the speed at which the tire rotation was initiated creating more likelihood of shimmy. As in, setting the tail down after a wheel landing is likely slower tailwheel speed than the initial upon 3-pointing. Would that make a difference?
As someone who has not experienced notable tailwheel shimmy, even when heavy (3100+ lbs), I don't know. Guess I'm fortunate thus far.

Using a wheel landing is great, but to paraphrase an old saying: You can’t keep that tail up forever. At some point, that tailwheel is going to come down due to lack of airflow over the horizontal tail surfaces. And if it’s tail heavy, as Mike noted, that’s going to happen sooner, as opposed to later.

I have three pointed a 185 in a significant crosswind while heavy, and used fairly heavy differential braking.....kept that tail solid in contact. But, again, that was a well set up tailwheel. I see a lot of pilots who pay zero attention to tailwheels.....and a few mechanics who pay almost no attention to tailwheels during maintenance.

I was assigned a brand new 185 in 1986, with 25 or so hours on the clock. It came with tailwheel lock, but our maintenance crew had removed the lock. I don’t know what their logic was, but I never really missed the lock in any case.

MTV
 
Johnnie

No doubt putting the tail down at slower speed is good on several levels. That said, I’ve had shimmy initiate at pretty slow speeds. One thing that helps initiate shimmy is having rudder (and therefore tailwheel) deflected when the tailwheel contacts pavement. Not a lot you can do about that in a X Wind.

As Airframes noted in the earlier post, bigger tires are more likely to shimmy, assuming the setup is prone to shimmy. Tail skis are great ways to get a Skywagon tailwheel to shimmy. If they’re set up right and maintained well, they should be fine, but the extra mass and arm of that ski can set up a nasty shimmy.

In FAI we were blessed with a ski strip and I always tried to use it as opposed to the pavement when possible with the 185 on retractable skis and tail ski.

MTV
 
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