Correct air pressure Tail Wheel

[MoonlightVFR]

During google search for Scott 3200 tail wheel information visited numerous type web sites.

There exist a wide difference in opinion about tire pressure for our tail wheels.

Surprised at variance. 12 LB to 45 Lb.

I am using 38 lbs.

What tire pressure did Scott originally certify?

One site even talked about injecting foam into tire to create a version "run flat" Bad idea I think.

[johneeb]

Grady this placard was in the glove box when the airplane came to me and these tire pressures have worked well for over 35 years.

[Bruce Fenstermacher]

Cessna specified 35 lbs on the placard found in all years of 170. This is curious as the Scott 3200 was not the standard tailwheel, the Scott 3-24B was. Problem is the 3-24B is a hard tire tailwheel not having any air pressure at all. The proper method to install a Scott 3200 per the TCDS is by Scott Installation instructions I-68. This instruction specified one should use the Scott tire pressure chart.

Looking at this chart reveals no specific pressure but that a deflection reduction of the tire diameter be the limit. As noted on the chart 9/20" or just above it is the limit or about .450". It is also noted this is 25% maximum. Most Cessna 170 W&B I've seen have the static load on the tailwheel at 110 to 125 lbs. So swagging the load at 150 to make it easy and going up that line to a line between 30 and 40 lbs (35lb) puts the deflection at about 1/4" or just above half the total deflection allowed.

You will note there is no minimum deflection required.

In conclusion you could put the maximum pressure the tire is rated and still be within the parameters of the instructions. However I can guarantee you won't have much tire tread in the middle of your tire after to long.

I recommend 35 lbs if for no other reason it will work and it matches the placard inside your glove box door or at least the glove box door your plane once had.

[ghostflyer]

I have run a pressure of 40 psi in the tail wheel with success and 25 to 30 psi in the mains depending on the next landing surface I am going to . When on beach sand it's down to 20psi and very limited braking . However I know of a couple of 180,s that have that foam in the tail wheel with success so far. It's only been about 3months so I am watching with interest .

[Pdogace]

I have been running My Scott at 45 psi on both grass and pavement for the last 3 years with good results. I check the pressure every couple months and always inflate to 45. I do mostly wheel landings. I run my main 7 inch tires at 24 psi and seems to work very well. Just my experience so far.

[cessna170bdriver]

I've always just aired my tailwheel tire up until it "looks about right".

[gfeher]

When I bought my plane, a previous long-time C-170 owner said I should inflate the tail wheel to about 45 psi because the tailwheel can go flat in tight turns and the higher pressure prevents this. I can't recall seeing anything about it on the forum, so I'm curious to hear what others think about it.

[falco]

I've always just aired my tailwheel tire up until it "looks about right".

Me too. And when I do measure it, "looks about right" is between 35-45 psi.

[daedaluscan]

c170 Glove box hinge.jpg

Grady this placard was in the glove box when the airplane came to me and these tire pressures have worked well for over 35 years.

I have glovebox and placard envy.

I use 40 and usually when I check it next it is down to 30 or so. Ive had one flat in 500 or so hours. 8:50 x 6 mains I run anywhere from 12 to 20. Way harder to move the plane at 12.

[bsdunek]

The problem I find is, that with the small volume of the tire, every time it is checked it has dropped off a few psi. I use a foot pump with a build in pressure gauge, and pump up to about 45. Then I try to remove the air chuck quickly to lose as little air as possible. Then it "looks about right". Dad did it that way and I continue - has worked for 66 years now.

[canav8]

When I bought my plane, a previous long-time C-170 owner said I should inflate the tail wheel to about 45 psi because the tailwheel can go flat in tight turns and the higher pressure prevents this. I can't recall seeing anything about it on the forum, so I'm curious to hear what others think about it.

I have found this to be true also Gene

[gfeher]

Thanks Doug. I've been keeping mine at 45 psi since I bought my plane and have not had the slightest problem even though I've made a lot of sharp 180 turns on the ground on both grass and asphalt (turn arounds on narrow runways). So I'll continue unless I hear a good reason not to.