new tail wheel spring issues

How to keep the Cessna 170 flying and airworthy.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

User avatar
Bryce D
Posts: 8
Joined: Tue Jun 02, 2015 5:36 pm

Re: new tail wheel spring issues

Post by Bryce D »

Thanks for all the the responses! I lifted the tail and inspected the attachment points. i don't believe there is any gapping on the lower mount, there is a small spring with a little lip that is made to keep a rubber bushing from sliding back towards the tail wheel.. as i was inspecting the spring i grabbed ahold of it and noticed more that what i thought of movement in the top through bolt.. i re torqued the bolt and found it to have loosened. I think it was the rubber bushings settling out after a couple touch and go's. it has less twisting now but still a slight amount. i did tighten my chains, i think that will help my ground steerability. before these springs it had the compression style and any tension would cause the scott to bind and not break over at all but the correct style allows it to break over just fine with a bit of tension on the chains. the angle of the caster section is not level, but is it within tolerance? im not to sure how to change it. i guess i can add a spacer to the front mount?
Attachments
IMG_5133.JPG
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: new tail wheel spring issues

Post by GAHorn »

The caster looks good to me.

Here is a good view of how the caster should be (pay no attention to the fact it's not installed on a 170.)
tws.jpg
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
User avatar
moss farmer
Posts: 26
Joined: Mon Jan 28, 2013 11:24 pm

Re: new tail wheel spring issues

Post by moss farmer »

I took my Scott 3200 tail wheel off and cleaned the excessive amounts of grease from the exterior and interior of the unit. My question is how tight should the nut be on the bolt that holds the unit together? I tightened it until the unit could not be swiveled and backed the nut off so the unit would swivel. Was that correct.

Ron
User avatar
moss farmer
Posts: 26
Joined: Mon Jan 28, 2013 11:24 pm

Re: new tail wheel spring issues

Post by moss farmer »

I learned from the club that my tail wheel was excessively greased. It would wobble as I taxied. Will tighten the castleated nut to take 15 ft/lbs. thanks for the help.

Ron
User avatar
moss farmer
Posts: 26
Joined: Mon Jan 28, 2013 11:24 pm

Re: new tail wheel spring issues

Post by moss farmer »

Thanks for the correction. That is a substantial difference.

Ron
Tailwind Farm
Posts: 16
Joined: Fri Nov 20, 2020 8:59 pm

Re: new tail wheel spring issues

Post by Tailwind Farm »

Bruce Fenstermacher wrote:Well I don't think it looks right. There is way to much caster. Looking at the thin red lines I drew on the picture at the base of the bracket assembly of the tailwheel should be flatter. Only slightly raised in the front over the rear. When the aircraft is loaded to 2200lbs it should actually be flat.

I think it looks like the spring pack is not installed in the fuselage bracket right causing it to exit the bracket at to steep of an angle. There shouldn't be a gap at the red arrow head. This is where I'd look for miss installed parts and correct if found to allow the spring pack to exit at less of an angle thus changing the angle the bracket assembly is held

IMG_5122.JPG
What is happening with this much caster is that to turn the wheel the aircraft has to be lifted and that just isn't going to happen and the control springs will just stretch.
Isn't the 5th spring in there where red arrow is? As for the thin red lines, it's hard to tell with that wheel position but I think the airplane shows a good positive castor. I doubt its at max gross.

Hard to tell about the spring tension in that left turn picture.....

Pretty new to the 170B but my chains , with the tailwheel centered, are pretty taught. Like twanging a guitar. I doubt that's right! Lots of power and brake tapping to turn.
User avatar
GAHorn
Posts: 20967
Joined: Fri Apr 12, 2002 8:45 pm

Re: new tail wheel spring issues

Post by GAHorn »

The tailwheel steering chains should be “just taut” ….. IE, the springs should be tensioned but not stretched…. when the tailwheel is straight-ahead.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Post Reply