Tailwheel lock

Mtns2Skies

Mtns2Skies

Final Approach
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Mtns2Skies
First do both 180's and 185's have them? or just 185's?

I understand they're used for takeoff and landing... but what's the advantage? Why are they just in larger tailwheel aircraft?
 
The 180 and 185 can have either setup. The type certificate allows for several different assemblies, and there are several STC's available. The lockable tailwheel is intended to control shimmy, and to allow for easier taxi control in strong crosswinds.
 
It stops tailwheel shimmy, helps you taxi in crosswinds, and helps prevent you from ground-looping on landing. If you don't lock it before takeoff, you can't lock it once you take off and the tension is off of the spring. If you forget once on a T-6, you won't forget again!

They're not on all big planes. The bigger the tailwheel, the more stable it is. The small planes like my 140 don't have one either. I'm assuming because we takeoff and land so slowly... not really sure.
 
My 180J has one. It's been disabled for 20 years. In that time I've had four different tailwheels, three of them big, and three different penetration skis including my current ski that fits my Baby Bushwheel. I've never needed or wanted the tailwheel lock.
 
What happens with a Scott tailwheel and similar setups is the wheel moves with the rudder. So if you land in a crosswind, with rudder, the wheel is cocked a bit and it kicks the plane (actually away from the crosswind which is good), and sometimes sets in motion tailwheel shimmy. Oh well, thats part of the fun and challenge of a tailwheel! Since mine doesnt have a locker, I just enjoy it. YMMV
 
Do you have any steering capability at all on the ground if the tailwheel is locked?
 
Just rudder and brakes. You unlock it after you land. They are pretty rare.

All the Piper Super Cubs, Citabrias, Huskys, Maules have Scott Tailwheel set up as well as most Cessna 180's. Some of the 185's have locking tailwheel standard.

Another option is just a fully castering tailwheel. Not as good. No tailwheel steering at all.

All in all, on a small airplane, the Scott is the best. Who needs another handle?
But, we pilots use what the plane has...
 
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Sac Arrow said:
Do you have any steering capability at all on the ground if the tailwheel is locked?
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Assuming a true locking tailwheel (as opposed to a steerable tailwheel like the Scott), the only real steering capability you have with the tailwheel locked is with brakes, but the whole idea of a fully locking tailwheel is to keep it straight on the runway while you are rolling out. You'd typically only lock it before takeoff once you are lined up on the runway and unlock it just before you start turning off after landing.
 
People need to get rid of this idea that if you have a castering tailweel or more common a castering nosewheel that you dont have any rudder steering. You do even at low speeds. Try it if you dont believe me. Ive seen numerous instructors teaching that you HAVE to use your brakes with castering setup. Air rudder works. You dont have AS MUCH steering with the rudder pedals, but you do have some, quite a bit actually. Try it if you dont believe me. I owned an amphib with castering nosewheels and have flow Diamonds with castering and some others. And they all had considerable steering capability with just the rudder pedals. Stick your hand out the window and feel the amount of wind even at idle, its signifigant.

Now turning with the wind, I agree, you're gonna need the brakes...
 
The 185's locking tailwheel was made my McCauley, not Scott, and a new one now costs something like $13,000.

I don't care for Scott wheel, either. Most any tailwheel manufacturer uses friction of some sort to try to limit shimmy, and that just makes steering harder and if the wheel is cocked a bit on takeoff it will tend to stay there and exert some rudder force and make the airplane fly cockeyed.

Shimmy needs to be dealt with through dynamic wheel balancing and making sure that the steering axis is vertical or tilted back (at the top) a little. Tired tailsprings (the suspension) is a leading cause of tailwheel shimmy. In that regard, the nice long stiff rod Cessna used on the 180/185 gives no trouble at all.
 
I like the Scott, because it is on my plane! Must be some reason the Super Cub, Citabria, Husky, and really a Maule tailwheel is very similar all use it. Yeah it kicks a bit on a crosswind setdown, but thats half the fun!

The 185 I flew didn't have one, or if it did, we didnt use it.

What do you get on the 185 if you dont lock the tailwheel? Full castering?
 
coloradobluesky said:
People need to get rid of this idea that if you have a castering tailweel or more common a castering nosewheel that you dont have any rudder steering. You do even at low speeds. Try it if you dont believe me. Ive seen numerous instructors teaching that you HAVE to use your brakes with castering setup. Air rudder works. You dont have AS MUCH steering with the rudder pedals, but you do have some, quite a bit actually.
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Wait a minute....the only person here who said you don't have ANY steering with a castering tailwheel is you....

coloradobluesky said:
Another option is just a fully castering tailwheel. Not as good. No tailwheel steering at all.
Click to expand...
 
I have a Haigh style locking tailwheel on my Pitts and a steerable API on my Eagle.

Even with the TW locked, there is some allowance for steering, and using rudder works just fine for taxiing. If I need a sharper turn, unlock TW and press a brake.

Pretty much the same with the Eagle's API, it takes brake to overcome the centerlock on the TW.
 
Lowflynjack said:
They're not on all big planes. The bigger the tailwheel, the more stable it is. The small planes like my 140 don't have one either. I'm assuming because we takeoff and land so slowly... not really sure.
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Fearless Tower said:
Until you get into the big heavy tailwheels (Beech 18/DC-3/B-17 and some early T-6s). Then they are pretty standard.
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I'm confused, while I would agree that larger tailwheel planes are more stable, then why do more have locking tailwheel?

I apologize for my ignorance my tailwheel knowledge is limited to a citabria and Texas taildragger 172.
 
Mtns2Skies said:
I'm confused, while I would agree that larger tailwheel planes are more stable, then why do more have locking tailwheel?
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Well.....I wouldn't say they are more stable on the ground. They do resist the wind a bit more, BUT, the heavier the airplane, the more momentum it can develop on a swerve and the more momentum you have, the harder it is to stop the swerve if it starts.

In a heavy airplane like a Beech 18 or DC-3, you really need that locked tailwheel to resist the initial swerve to begin with. You could probably takeoff okay without it locked, but you would have a real challenge landing it with it unlocked. Also, I suspect that it would be difficult to have a 'steerable' tailwheel on those airplanes because of the weight.

A T-6 is light enough to have a steerable tailwheel and many have been converted, but if you fly an early model that has not been converted to the steerable TW, then you do need that locking feature.
 
A B-17 has a tailwheel lock.

That's all I have to offer to this thread.

Sorry.
 
My 185 doesn't have one, I've flown a few planes with them, helps on roll out with heavy xwinds.
 
Cpt_Kirk said:
A B-17 has a tailwheel lock.

That's all I have to offer to this thread.

Sorry.
Click to expand...

H-60 has a locking tail wheel also. That's all I have to offer to this thread.:D
 
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