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Bearhawk tail wheel maintenance - steering seizes

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  • Bearhawk tail wheel maintenance - steering seizes

    Hi guys - I recently noticed our tail wheel steering was stiff, not steering smoothly either, kinda jerky. I didn't think too much of it.

    Weeks later, I found that it suddenly became pretty hard to control the plane with a heavy load aboard, when taxiing or landing. It was controllable, but a decent crosswind would have made it fairly nasty to handle. It required constant re-corrections, big pedal inputs, to keep it straight.

    I had given the tail wheel parts a good clean and lubricate several years ago, and it has been a couple of hundred Hobbs hours since then too. Cleaning every part, removing all the old grease, and re-lubricating from scratch returned the tail wheel to original operational condition.

    There was a fair bit of black / grey grit in the barrel, and the grease was pretty dry. Some areas the grease had dried to a hard scale. The brass bushing was a little scored from rubbing, and the underside of the retaining cap on top was starting to corrode. But no lasting damage, good lubrication has made it as good as new.

  • #2
    Thanks for posting, Battson. You're so far ahead of most of us, and we all appreciate your "maintenance tips" that you provide from time to time, based on your experience. Thanks!
    Jim Parker
    Farmersville, TX (NE of Dallas)
    Patrol Quick-Build Serial # P312

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    • #3
      It seems I have to do this at least once a year... it sounds like yours held up well for that long!

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      • #4
        I live on a grass strip. I clean and lube tail gear at each oil change . Stinger
        ,

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        • #5
          An annual clean and lube is the standard on my Alaskan Bushwheel as well, part of the tail dragged scene.

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          • #6
            Sounds like everyone else knew to lube that tailwheel, which is great.
            I have a pretty extensive maintenance plan written up, but I did not think of that.

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            • #7
              Originally posted by JimParker256 View Post
              Thanks for posting, Battson. You're so far ahead of most of us, and we all appreciate your "maintenance tips" that you provide from time to time, based on your experience. Thanks!
              Kind words Jim - I see it like a "circle of life". Or maybe just a Bearhawk building lifecycle. When I started out, there were a host of big names in the community who I looked up to - still do.
              Eric, Mike, Georg, Pat, Dave, Dan, John, Jan, Jim, Robbie but I shouldn't name names because I am going to forget so many people!!

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              • #8
                Battson,
                Like all your posts...thanks.

                Professionally I build/establish scheduled maintenance requirements and maintenance programs. MSG-3 is the process the industry uses for big airplanes, but the process is working its way into light (certified) aircraft. You can go blind reading about it and there are a lot of "snake oil" salesmen out there selling "MSG-3 programs". Bottom line is you look at every aircraft function and ask some safety, availability (mission), and cost questions to establish a scheduled maintenance requirement. The interval is based on reliability calculations and service experience.

                Typical maintenance programs have four areas Structure, Systems & Powerplant, Zonal and L/Hirf. It sounds complicated but its really not and actually is better than assigning maintenance to every component.

                With a number of you guys that are "leading the fleet" with your flight time, this is perfect for data to build up a set of maintenance requirements. These can be organized for high and low utilization aircraft operators.

                Bottom line is if you've ever wondered how a Boeing 747 with 6.5 million parts and over 55K functions is maintained with less than 2000 scheduled maintenance requirements, and maintain over a 99% aircraft availability all while flying 10.5 hours a day, every day for 30 years, only stopping (coming out of service) every 45 days and 18 months for checks...now you know!

                Wyo Johnson (Andy)

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                • #9
                  I have made a full exploded view drawing of the Bearhawk tail wheel if you are wondering how it goes together. PM me to get one.

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                  • #10
                    I think Andy’s plan is a little OTT for a light aircraft. (By the way, 18 hours a day is probably closer to the mark....). However, there are plenty of generic maintenance plans out there for experimentals that provide a good start point. The important thing is that the plan is modified in light of experience. For instance, if you plan to check/lubricate the tailwheel every annual and you find it in poor condition, then you might up it to every 50 hours. I did this with the wheel pants on my RV10 which really take a hammering if you operate off grass.

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                    • #11
                      PaulSA,

                      Sorry don't misunderstand what I saying about MSG-3. There are two ways to approach maintenance, assign maintenance to components (1950s) or look at aircraft functions and then look at the effect of the loss of that function. Maintenance is to detect and correct degradation of a system function so that was what I was driving to...look at system functions and determine whether or not you need maintenance. If you look at aircraft function it's easier and safer (and cheaper) to manage the aircraft...right maintenance and the right interval.

                      As a kid, the 100 hr checks on my Dad's cub were like an annual for most cubs as we used them for aerial hunting and flew the aircraft extremely hard. We also had "extra" maintenance requirements due to changes to the aircraft like a marking pod on the LH gear and a radio rack for the giant radios they used as the federal government only bought one model of Motorola radios (actually a large truck radio!) and we had to mount them under the back seat as to not screw up the CG. Dad's fleet (6 aircraft) where the ones Piper used to find a number of the AD's that drove changes and checks to the Super Cub fleet. This is why I like reading about Battson's flying and maintenance as guys like him are on the leading edge of the utilization envelope.

                      Most maintenance requirements out there for small aircraft and even large aircraft are copied from previous designs. I was mainly thinking out loud and since the Bearhawks are a great design and just figured that it needs it's own unique maintenance program, not one scabbed off a Maule, Cub or RV. In the 1990's Boeing operators used to lube the ball mats in the cargo bays because "every dummy knows you lube ball bearings". The problem was most operators lubed them too much and with the wrong lube and the balls would catch dirt and fail...cancelling a flight. When functional analysis was applied (MSG-3), they moved the requirement (as it was still needed) to 18 months, but changed the lube to a dry lube. Problem solved.

                      My take away on Battson's tail wheel problem is to think about what are the functions and failures, what happens to safety, mission reliability and cost when those failures occur and what check/maintenance can I do to detect and correct the loss of function...then apply at interval that meets the inherent reliability of the system and my utilization.

                      We spend a lot of time building these machines...and almost no time thinking about how we keep safe, reliable and at an operating cost we can stomach!

                      Sorry I'm not a nerd, but I play one at work

                      I should probably move this conversation over to the "maintenance" section that Jared was talking about.

                      Andy

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                      • #12
                        Never heard of MSG-3, need to look that up.
                        I know all about and am qualified in applying RCM-II, which is the second iteration of the original step-change from 1950's maintenance "Reliability Centred Maintenance (RCM)". I think RCM branched off about the time of MSG-1 finishing up.

                        Started on an RCM progamme for the Bearhawk, then realised it was a sledgehammer to crack a nut.

                        The CAA described my maintenance programme as the "Rolls Royce of home-built maintenance plans", which foolishly I took pride in, but still I overlooked the tail wheel among one or two other things. Pride before the fall huh.

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