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Please post thoughtfully in this section. Create/maintain one thread per mishap. Focus the discussion on the event, and learning from it, rather than on the individuals. Keep in mind that any damaged Bearhawk may represent many years of lost work, many thousands of lost dollars, injury, or worse. Create posts that will enhance safety of the Bearhawk fleet and educate other Bearhawk operators. It is not always easy for someone to come forward after a mishap, be tactful and don't make someone regret admitting a mistake.
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Tailwheel challenges

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  • Tailwheel challenges

    Hi All

    I’m not a genuine ‘Bearhawker’.

    The only plane I’ve ever built was a paper dart to fill in time at school.

    I don’t profess to know the Bearhawk intimately. When folk start talking part numbers and build techniques I find myself a long way out of my depth.
    I enjoy the forums, but don’t participate much.

    My relationship with Bearhawks only goes back about seven years when a close family member (Dad) purchased a flying four-place. During this time I’m very fortunate to have been allowed to fly ZK-FHR regularly gaining about 150 hours.

    As a career commercial pilot, I’ve spent 23 years flying a variety of different types including about 1500hrs tailwheel in types like Cessna180/185 Maule, Glastar, Bearhawk and almost 1000hrs in DC3’s. Often flying with heavy loads in challenging scenarios.
    GA pilots say ‘bloody airline pilots’. Airline pilots say ‘bloody private pilots’.
    Giving regular flight instruction in GA as my airline career continues with Air New Zealand has me defending both sides and trying to take the best of each side to pass on some techniques and philosophy’s in my instruction.

    Ab-initio flight training isn’t really my favourite, I’m far more interested in extending and consolidating pilots skills in the playground that New Zealand has to offer. The mountains, valleys, and airstrips we enjoy are awesome.
    But they all require respect, as do the aircraft we operate.

    My teaching is typically with a private owner, in their own aircraft or one they operate regularly.
    As a flight instructor, my efforts go into the philosophy, mindset and decision making in that pilots operation, as much as the technical handling of an aircraft.
    My lifetime has been spent around aviation. I’ve made a number of cock-up’s. I’ve seen a lot of stuff-up’s and I’ve heard some horrendous stories.
    I’m simply lucky to have some interesting and varied experience with qualification to pass on to other pilots, but I’m no Bearhawk guru.

    The Bearhawk is a great aircraft, but it’s not the perfect aircraft.
    There’s no such thing as the perfect aircraft.

    Like any aircraft the Bearhawk has its compromises, its pitfalls and its challenges.

    The Bearhawk, like any any aircraft has a critical angle of attack. An angle of attack where the aerofoil will stall. A stalled wing is no use to us pilots, so we operate with a comfortable margin.

    The Bearhawk has a powerful rudder. It takes some getting used too.
    At slow speed, this is an asset for controllability.
    At high speed, it can be a curse. Easy to over-control. Very easy to fly out of balance for extended periods of time.
    One of the biggest risks from flying out of balance, especially at slow speed, which is often at low level (think base turn) is stalling out of balance. Using too much rudder in the turn (skid), and not having enough margin above the stall will induce a spin, and you will die if this happens at low level.
    Fly with margin. Fly in balance.

    Most aircraft don’t have sight-glass fuel indicators, but the Bearhawk does, and it’s a fascinating indication when out of balance.

    The fuel system, as I understand it, has two ‘pickups’ on each main tank.
    If one pickup becomes uncovered, the other should continue to gravity feed. If the other pickup becomes uncovered, we’re sucking air. The noisy engine goes quiet.

    The only fright I’ve had in the bearhawk has been when neither of the pickups were covered. Taking off, with only minimal fuel in the tanks for a five minute flight to a nearby fuel pump, I elected to takeoff with fuel selected to the fullest tank. Turns-out, the rear pickup was blocked. With the nose raised to a climb attitude, the front pickup became exposed. Noisy IO540 went quiet. Engine Failure at Takeoff training has taught me to lower the nose. Pickup now covered and engine splutters into life. Phew.

    Whilst this was a technical problem, with the blockage that was uncovered later, the same would happen if the fuel state was low. Not necessarily illegally low, but low enough that if flow out of balance, the pickups could be uncovered.
    Fly with margin. Fly in balance.

    Recently, directional control issues have made the headlines.

    There’s a variety of reasons for these, but here’s what I pass on to folk doing a tailwheel rating (or checkout).

    The first step is to understand the CofG location, being aft of the main wheels which is the reason for the tail sitting on the ground.

    In any aircraft, the pivot point is an imaginary needle pointing vertically from between the main wheels. It’s only natural for the centre of gravity to want to be forward of the pivot point, and ‘drag’ the pivot behind.
    That works perfectly for tricycle undercarriage aircraft, but unfortunately it means tailwheel aircraft would be directionally stable going backwards.
    Tailwheel config aircraft are inherently directionally unstable.

    The only way we can counter this instability is to keep four points in line
    1 - CofG,
    2 - the pivot point
    3 - the nose of the aircraft
    4 - the line of the airstrip.

    In practical terms, we need to keep the aircraft straight. REALLY STRAIGHT.

    Sounds simple. But it’s not. It takes practice. Lots of practise.

    A couple of good exercises.
    1. Balance a broom on one finger, with the broom head at the top. Your hands will be busy keeping the broom balanced, just like your rudder pedals.
    2. Go shopping. Next time you’re at a supermarket, push the trolley backwards. Then start running. The centre of gravity is aft of the pivot, just like in the aircraft. Your hands will be busy keeping the trolley straight, just like your rudder pedals in an aircraft.
    Once in the aircraft, set high standards of what you as a pilot will accept.
    The aircraft must be flown accurately and with suitable margin.

    Practise, practise, practise.
    Following initial checkout I prescribe pilots to go out at least three times a week for the next 10 weeks and do five landings each time. 15 landings/week x10 = 150 landings. Good consolidation following intro to a new type.
    This pilot is now current, and most importantly knows what currency feels like and be able to identify that feeling in the future.
    It might sound expensive, but it’s the much cheaper than a damaged aircraft.
    The skills learned in that 10 week period will be with that pilot for life.

    Practise go-arounds. These are often seen as ‘abnormal’ by GA pilots.
    A go-around is a normal manoeuvre.
    Sometimes pilots don’t do a go-around for several years between flight reviews, and they get messy, fast.

    I encourage new tailwheel pilots to stay away from tailwinds and sealed runways, especially with aft CofG and/or heavy aircraft.
    The difference between landing with a five knot headwind vs tailwind is huge. The control surfaces are considerably more responsive in the critical stages of rollout with a headwind.

    Avoid touch-n-goes.
    In real life, we takeoff from a standstill and we land to a stop.
    Practising the takeoff is just as important as practising the landing.
    Applying full power, while almost stopped and tailwheel just off the ground is a very very tough time for directional control.

    One aspect that is often overlooked and/or underemphasised is the use of Ailerons to assist in keeping the aircraft straight.
    Keep pointing the aileron into wind.

    As experience is gained you’ll find that you feel the change in direction even before you can see the nose move sideways. These get countered by smaller, earlier movements of rudder.

    After a while, three key areas develop. Competency, Currency, Confidence.
    It’s your job as a pilot in command to manage these aspects of the operation and make decisions appropriately. I cannot emphasise enough that deciding to operate with margin to spare is the best way to keep an aircraft in one piece.

    Fly with margin. Fly in balance. Fly within your abilities.

  • #2
    Very well said!
    What to do why to do and how to do.

    Kevin D
    #272

    Comment


    • #3
      Thank-you for your insight

      Comment


      • #4
        An image of Bearhawk fuel system that is built iaw Bob's design is shown below. It will have a finger strainer at each of the tank exits. The front and aft fuel lines will tee near the floor just ahead of the door. Fuel is gravity fed to the selector on the floor and then to the fuel pumps. Its debatable if a Bendix FI system suction feeds....I think probably not, but it could and would depend. I think varibles include: the fuel line ID, choice of fittings, and fuel flow demanded by the user. The High fuel flow on takeoff that you performed would be the most demanding on the system. Use of sharp 90 degree fittings hurts flow rates for example.

        When the system is functioning properly with low fuel, the front finger strainer may not be covered by fuel in the tank but the line upstream of the tee will be flooded to the level of the fuel in the back of the tank.

        If we look at the image and rotate it 13 degrees clockwise in our minds, we might be able to visualize this and understand how the fuel will exist on the ground with 6 gallons of fuel in a single tank.
        Screen Shot 2023-07-11 at 10.19.16 AM.png
        Brooks Cone
        Southeast Michigan
        Patrol #303, Kit build

        Comment


        • #5
          Looks right.

          The blockage was the issue. Unfortunately the blockage was also probably the reason this was the fullest tank.

          Another consideration is the uneven nature of fuel consumption.
          the consumption wasn’t even, but is wasn’t considered enough to raise concern.

          if you’re flying balanced, and the fuel drains from one side more, maybe checkout why.

          since the blockage was uncovered and fixed, fuel has drained equally ?
          Last edited by DJPaterson; 07-12-2023, 03:38 AM.

          Comment


          • #6
            I recently revisited this thread and wish to thank you for sharing your experience and wisdom.
            Fly with margin. Fly in balance. Fly within your abilities. -- Excellent advice!

            Comment


            • #7
              I had forgotten about this post…excellent information. My BH is heading to the airport next week for final assembly and last night I took my first flight in an C182 after over four years out of the cockpit. Things are coming together quickly, but I’m taking my return to the air seriously. People keep asking when my first flight will be and I tell them when I’m ready. Ready means lots of flying and transition training…this reminds me that I’m on the right track and to be patient!

              Comment


              • svyolo
                svyolo commented
                Editing a comment
                Hopefullly I start TW training next week. After not flying GA for 42 years. I am in the same boat.
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