Tailwheel Steering

akflyer · Post by **akflyer** » Tue Jul 27, 2004 4:13 pm

My recently purchased ragwing has very minimal tailwheel steering when taxiing, particularly to the left. When rolling out after landing and taxiing it is usually necessary to use the brake on the left side to stay straight. During a pre-purchase annual the left brake pad was quite a bit more worn than the right (they were installed at the same time) so this may have been going on for some time.

My mechanic has taken the tailwheel (Scott 3200) apart and inspected it and it is in good shape. He also tried switching the springs, which had no effect. Any ideas out there? Thanks! Kevin

doug8082a · Post by **doug8082a** » Tue Jul 27, 2004 4:50 pm

You mention needing to use the left brake to stay straight when taxiing. I had a similar problem with my "B" when I bought it. The plane had sat for some time previously and the right brake was partially seized. The puck had corrosion that prevented it from moving and caused it to be partially engaged all the time thereby requiring excessive opposite brake to compensate. Have a close look at your brakes and make sure they are not dragging.

My $.02

Post by **Bruce Fenstermacher** » Tue Jul 27, 2004 4:56 pm

I'm with Doug, check your right brake. It's probably dragging.

akflyer · Post by **akflyer** » Tue Jul 27, 2004 5:58 pm

Thanks for the speedy replies Doug and Bruce! The right brake is free and not dragging. I should have said that the plane taxis straight, but any left correction needed from uneven pavement, wind, gradient, etc. usually requires brake.

Kyle Wolfe · Post by **Kyle Wolfe** » Tue Jul 27, 2004 11:24 pm

I don't have my parts book at home so I can't provide you with the appropriate parts number, but I had a similar problem not wanting to turn to the left.

Check the spring in the tailwheel which looks like this \___/ Mine was a bit too long and was not engaging into the v-notch in the tailwheel. So when pushing on the rudders the cables would tighten and apply pressure, but since the spring was not engaging into the notch it simply slid by and would not turn the tailwheel in direction. Make certain this spring is engaging the slot.

ak2711c · Post by **ak2711c** » Wed Jul 28, 2004 6:30 am

Kevin, you will find that even if there isn't anything wrong with your tail wheel steering you will still have very minimal tail wheel steering just by its design. However it shouldn't be just to one side. You'll find that good brakes are a must. Wait untill you try taxiing on skis with no brakes. You don't realize how much you need them until they are gone. If you get in a little crosswind while taxiing on skis it can become impossible with out having someone walk the tail for you. Good luck!
Shawn

mrpibb · Post by **mrpibb** » Wed Jul 28, 2004 2:44 pm

With your tailwheel locked lift the tail to see if it is alignment with your rudder. Hows your main gear alignment?

akflyer · Post by **akflyer** » Wed Jul 28, 2004 5:29 pm

Thanks Shawn! Good to know that maybe I am expecting too much in the way of steering.

akflyer · Post by **akflyer** » Wed Jul 28, 2004 5:30 pm

Hi Vic! When we had the tailwheel up it appeared to be in alignment with the rudder. What is the best way to check main gear alignment? Thanks!

zero.one.victor · Post by **zero.one.victor** » Thu Jul 29, 2004 12:00 am

A quick & dirty way to check wheel alignment:
1) Put a straight-edge across the front of both main-gear tires, up on a couple blocks ( like on 4 x 4's)
2) Use a long-ish framing or combination square to check the flat inboard side of the brake disc's against the straight-edge. With the airplane loaded up to 2,000 pounds,ideally the disc's should be square to the straight-edge--in other words,neutral castor (zero toe-in/toe-out). I'm not too sure how much effect positive/negative camber has on handling-- I think that's more a tire-wear thing.
My ragwing has neutral castor and positive camber ( top of wheels tilted out) at around 1550 pounds-- in other words,ready to fly but with no people on board yet-- and it seems to handle fine.

Eric

Roesbery · Post by **Roesbery** » Thu Jul 29, 2004 12:58 am

Also check with a straight edge or string line from the outside of the wheel to the horizontal on each side. This will tell you if the wheels are alinged with the rest of the plane. Keeps you from taxiing like a dog trots.

zero.one.victor · Post by **zero.one.victor** » Thu Jul 29, 2004 3:33 am

Yeah, I also checked this out by triangulating-- I measured from a bolt at the bottom of the tailspring bracket (on the centerline of the airplane at the aft end) to the lower aft axle bolt at each gear leg. Should measure out the same if the gear legs are straight & installed properly.

Eric

akflyer · Post by **akflyer** » Fri Jul 30, 2004 5:15 am

Thanks to all for the various methods to check alignment. I may try them all just to be sure! Kevin

N73087 · Post by **N73087** » Fri Jul 30, 2004 10:03 am

Check the spring in the tailwheel which looks like this \___/ Mine was a bit too long and was not engaging into the v-notch in the tailwheel. So when pushing on the rudders the cables would tighten and apply pressure, but since the spring was not engaging into the notch it simply slid by and would not turn the tailwheel in direction. Make certain this spring is engaging the slot.

There are two shims or spacers that go with that spring. It is important the thicker is installed "inboard." I found that it made a big difference, and corrected my steering problem.

mvivion · Post by **mvivion** » Mon Aug 02, 2004 2:17 am

Sorry, folks, but tracking the main gear isn't quite that easy. What's been outlined to this point is a good starting point, but the definitive procedure to determine main gear track is to put the airplane on grease plates. It isn't necessarily the airplane at rest, sitting in the three point attitude that you necessarily need to look at. Cessna gear moves in many directions during any landing roll.

The problem with the technique described to date is that all it does is measures where the wheels are relative to what the airplane did last. Friction is a wonderful force, and will massively influence the results you see using this procedure. Roll the airplane backward first, and the wheels will point one direction. Roll it forward first, and they'll point in the opposite direction, etc.

Find a good Cessna tailwheel mechanic who understands working the airplane through a grease plate process, and you WILL find a huge difference. Basically, they take four plates of steel, put grease between each pair, then set the airplane down on the grease plates with a hoist.

The grease plates take the friction issue out of the picture, and tell you what your gear is actually wanting to do. Without the grease plates, you'll never know if what you are seeing is simply an artifact of friction.

Mechanics hate the grease plate program, because it requires a lot of messing around with the shims behind the axles to get the gear aligned.

DO IT, THOUGH!! I know of at least one C-170 owner who was about to sell his airplane till he had it done, and wound up in love again.

My airplane was badly out of track, and a semi-handful on pavement.

Also, exchange your tailwheel steering arm (and dust caps) for a Scott 3214T steering arm. It has upturned steering arms, and MUCH better steering geometry. Add to that compression steering springs, and you'll have a much better steering airplane.

Stock 170's don't steer well, and I've heard people say to just accept that. BS, you can make it better, and it doesn't cost that much or take that much trouble.

Mike Vivion