Scott 3200 tailwheel question

How many of the 4 holes inside the hub should have the small springs?

Trick question.
DENNY

5 holes. It just depends on how hard you want it to brake. If you want it softer so the tail brakes easy as you push it around do 3. Cessna guys tend to run 5. But may do 3 or 4 depending on what the IA wants or what they read on the internet. Still others gut the tailwheel (free castor) until they go to skis.
DENNY

I have 3 in my -12 and I think it's just right.

The amount of springs have nothing to do with breakout, all it does is add to the friction on the rotation. If you want a more "free" feeling rotation than 3 springs, if you would like a bit more friction or "controlled" rotation speed then add five springs. the Free castering tailwheel is accomplished with removing the "V" lock spring that fits into the steering arm that allows you to steer left and right and depending on the "Pawl" you have installed (3219-00/3219-01/3219-02) will determine the brake out angle to when the tailwheel will go to full swivel.

You need the rotation for the breakout, you can have the same issue with the wrong grease in cold weather.
DENNY

DENNY said:

You need the rotation for the breakout, you can have the same issue with the wrong grease in cold weather.
DENNY

Click to expand...

So what is the best grease for cold weather, in the interior of Alaska, for a tailski ? At -25, red grease and several synthetics seemed pretty hard, when I compared them on a piece of plywood last week, that I had left outside.

thanks,

Jonny O

What brands of grease did you try?

I have used Exxon-Mobile SCH-100 (Airframe's preferred lube-synthetic), Aeroshell 22-synthetic, and Lubriplate Low Temp-mineral. Mechanics often use Aeroshell 5-mineral or 7-synthetic year round in the shop in my experience. The problem is grease shouldn't be mixed (mineral versus synthetic base oil for example) as it can cause separation of the thickener and lube bases and other issues. So can sitting under pressure in the grease gun or load in the tailwheel.

Pick one and stick with it.

Exxon-Mobil SCH-100:https://www.exxonmobil.com/en/aviation/products-and-services/Products/Mobil-Aviation-Grease-SHC-100

Aeroshell greases: https://www.shell.com/business-cust...7f856b8e59a15ae28/aeroshell-book-5greases.pdf

Lubriplate Low Temp: https://www.lubriplate.com/Products/Grease/Multi-Purpose-Greases/LOW-TEMP/LOW-TEMP/

Gary

I will have to look but I think I am using the Aeroshell 22
DENNY

I've gone from aeroshell 22 to aeroshell 33MS and have had good results. The moly seems to help especially on heavy tailed 180/185.

That 33MS now 64 looks interesting. I've used some Lubripate Low Temp with 5% Moly from a Military spec surplus can but it takes disassembly. Moly (like found in automotive CV drive joint lubes) is good protection.

Gary

BC12D-4-85 said:

What brands of grease did you try?

I have used Exxon-Mobile SCH-100 (Airframe's preferred lube-synthetic), Aeroshell 22-synthetic, and Lubriplate Low Temp-mineral. Mechanics often use Aeroshell 5-mineral or 7-synthetic year round in the shop in my experience. The problem is grease shouldn't be mixed (mineral versus synthetic base oil for example) as it can cause separation of the thickener and lube bases and other issues. So can sitting under pressure in the grease gun or load in the tailwheel.

Pick one and stick with it.

Exxon-Mobil SCH-100:https://www.exxonmobil.com/en/aviation/products-and-services/Products/Mobil-Aviation-Grease-SHC-100

Aeroshell greases: https://www.shell.com/business-cust...7f856b8e59a15ae28/aeroshell-book-5greases.pdf

Lubriplate Low Temp: https://www.lubriplate.com/Products/Grease/Multi-Purpose-Greases/LOW-TEMP/LOW-TEMP/

Gary

Click to expand...

Wow ! Thanks for the links. Getting some real data is great. Companies that don't publish data on the web regarding cold temperature performance were not willing to give me that info. A very common grease in Fairbanks, Barrow, Kotzebue and Nome is Aeroshell 22. It would be good to have some Engineers explain this better, but it would seem that a wheel would have; grease wise, around 6 times more resistance to move at -40 using Aeroshell 22 than with Aeroshell 7.

What is that adding to your takeoff roll ?
Aileron input ?
Tail wheel yoke movement pressure ?

Here is a condensed version of the data:

Click to expand...

I put Aeroshell 7 in my tailwheel yoke and the difference was astounding.

Thanks again Gary !

Jonnyo thanks for sharing the summary and info from your experience. Lots of uses in the cold especially wheel bearings and adjusting screws. Not many tailwheels for commercial users so maybe the main focus is wheel bearings. I had some #7 for my Cub jackscrew but loaned it and never got it back. My #22 is old and needs to be replaced as some of the oil has separated from the thickener inside the ziplock bag.

I'd ask some of the mechs what they have found to last especially those along the cold coast where snow dirt and cold mix.

I had a tailwheel bearings freeze up in OTZ and blow out one year. Like they do it either warmed up then froze some moisture in the bearings or picked up some water
as we were operating off of Kobuk Lake (Sheefish fishery) and stiffed the wheel. Hit a bare spot on the runway heavy and ripped out the tube valve stem. Tire got flat so we jacked up the plane and stuffed the tire with a wet rag that froze to hold a round shape. After I carried a spare tire, tube, and hand pump plus greased it more often.

Gary

After working on Wip 3000 floats , they recommend several greases and I’ve gone to Green Grease, a marine grease. It seems to work good in the water and seems to stay loose in cold weather. The only thing is I do a lot of maintenance on these so I don’t know how it will hold up with little or no attention.

I've had tailwheels where the pins the springs go over shear or at the very least get loose. On one I was able to peen the end of the pins on the back of the metal disc to tighten. At the time in rural Alaska parts were hard to get but replacement now is easy. There was some fretting so I smoothed out the metal to metal contact but likely a lack of the right lube was the problem. During the Trans-Alaska pipeline construction era synthetic lubes were tested in real cold and later became available in stores. Now they''re common.

Gary