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  • Fuel system set up

    I have a rotax 447 ssdr magic cyclone. I want to check that the fuel system is set up properly from the tank to the fuel pump. It includes a bleed back system to deal with vapour lock. Does anyone have any pictures of a rotax 447 set up ( doesn't need to be a magic trike) or could someone do me a sketch of the best way to set this up? Thanks in anticipation.

  • #2
    Fuel system set up

    Steve,
    Had magic laser (2 off) - neither had anything as exotic as a 'bleed back'!

    Tank (corse strainer) - filter - pulse pump - carb (I also have put a second filter just before the carb - it does 2 jobs 1. It filters the fuel that is going in the carb 2. It is clear plastic and allows fuel to be seen entering the carb)
    The 'toilet valve' in the carb maintains the correct fuel level and the pulse pump simply maintains a pressure.

    Only other element to remember is the tank breather (if fuel comes out air must be allowed to go in - is this your 'bleed back'?) The breather must be set up to allow air in to replace the fuel but the breather tube must be routed to resist liquid fuel leaving the tank ( especially in a crash situation when the tank may be ' upside down' I.e usually positioned on one side at the top of the tank and routed to the other side of the tank venting to atmosphere low down.
    Please feel free to ask anything else!

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    • #3
      Fuel system set up

      Thanks Paul I like the idea of the extra fuel filter, might give that a try. It sounds like your (and John Perry Evans) idea is much simpler than I have at the moment. The problem with the set up I have (which was what the previous owner had done) is that there are too many little joins and when I push the primer bulb a little bit of fuel leaks out from the joints and I don't like any kind of fuel leaks such as this. I'm not really sure how much of a problem vapour lock is on an open trike and a 447 engine?

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      • #4
        Fuel system set up

        What did you think of the magic laser Paul?

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        • #5
          Fuel system set up

          The magic laser is a very good flying machine!
          When people asked me what I thought of the magic laser my answer was simple "don't look at the asi and it flies just like a Quik" (at the time I also had a Quik so had good confidence in that statement).
          Regarding your fuel system one other 'overriding mantra' should be 'as few joins as possible' and it would be my advice to put the system back to Magic standard.
          Of course it is ssdr so there is scope to 'enhance' - as a minimum you need to fit a bypass to the fuel priming bulb (they do fail and cut the fuel supply to the engine). I have removed the bulb completely and fitted an electric 'facet' pump (I fly a Chaser and have full electric supplies).
          As previous if you need any advice etc - just ask.

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          • #6
            Fuel system set up

            You also need to sort out the 'leaks'! A leaky fuel system is a serious Fire hazard but also may cause the engine to suck air.
            I use good quality fuel tubing ('gates' tubing is good - if you can get some,) and 'propper fuel clips' jubilee clips are no good at all!
            Do you have the fiber glass tank or the more modern replacement (fibreglass will rapidly deteriorate).

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            • #7
              Fuel system set up

              I just replaced the fuel tank for the latest one, first think I did. Plan to sort out leaks a sap. It leaks when I push the primer bulb and when it gets hard and I press again, fuel leaks out below the primer connection, this tells me the connection has the potential to leak so I am worried this is not right and that a loose connection here could cause a leak when I am flying and that I just can't see. Now you have said about bypassing the primer bulb I think that is what the set up I have here is designed to do. I think it just needs a slight re design and fitting better. Thanks for you advice, much appreciated. Where do you fly from? Out of interest what electric supply is needed for the facet pump and where did you get it? I have a keywest rectifier and small 2 .1 amp hour battery fitted to drive the intercom, radio and gps, would that be enough to drive the facet pump?

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              • #8
                Fuel system set up

                Paul, I just noticed your comments about the Bob try's ssdr on their Facebook page, I also like the look of this machine, very nice. Interesting we both happen to be looking at the same time!

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                • #9
                  Fuel system set up

                  Steve,
                  Keywest is fine bit of kit but your battery is likely a 'tad' too small (I have same battery as fitted to Quik - think it's 8 amp/hour). Facet fuel pump available from eBay etc from memory you need 40106 part number as it allows the passage of fuel even when switched off (some don't!). The facet pump makes priming a very simple operation and also aids starting as the fuel bowl is being replenished as the engine is turning over ( priming bulb cannot do that - unless you prime and pull start at the same time). One other thing you should consider is a capacitor as across the dc output (the keywest output is a 'ripple dc' and the capacitors smooths the ripple - you need as smooth an output as possible to minimise electronic interference to radio interface etc.

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                  • #10
                    Fuel system set up

                    I fly (not currently field been waterlogged for three months) from Margam in South Wales.

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                    • #11
                      Fuel system set up

                      Good new is I have fitted a 20k micro farad capacitor so that was a good decision and seems to work really well. I do have a bigger battery which from memory is about 7 ah but it doesn't fit as neatly into the set up I have and without a pod etc it's a pain trying to find places to put things on the magic, plus also the weight difference in the batteries is quite a bit, so for the moment until I can rethink the layout, I'll probably keep with the primer bulb and by by pass idea. I fly from Sittles in staffs near Lichfield and like you we are waterlogged. Thanks so so much for your help you are a star.

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                      • #12
                        Fuel system set up

                        I know that mounting stuff on a podless trike can be 'challenging', especially when your keel like mine (Chaser) is round!
                        I have used slightly oversized (allow for rubber packing) 'exhaust clamps' to very good effect - battery 'table' on chaser is two 61mm exhaust clamp bodies (not u rod) being joined by two strips of small section angle aluminium. Fits a treat, is held on with tie wraps and luggage strap and has not budged in 60 hours flying.
                        I would not be too worried about where to site things - weight shift trikes just 'swing' to a new position accommodating C of G changes. Only thing to be careful of is that on empty fuel the rear wheels touch first (think I remember minimum 100mm higher ride height to front as compared to rear).

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