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  • Re: Where to buy 5 year rubber replacement kit

    by » 5 weeks ago


    Hi all

    Rotax will not ever call out aircraft OEM related parts.  Given that a boost pump is part of the builders/manufacturers responsibility and there are literally hundreds to pick from they do not call out parts they have not tested or approved.  Only parts in the direct supply scope of Rotax are called out in the 5 year replacement listing.  Hoses, fittings, boost pumps and any parts not supplied by Rotax would have to be called out by the kit supplier or OEM of that aircraft.  

    To take that idea one step more with the release of the type 915 they began a policy of only showing and giving information on the supplied parts in the manuals, such as the parts and even the heavy manuals.  items such as intercoolers and radiators and the like, not with the supply of a new engine but sold separately, are now covered by what is called out as an SI PAC, service information parts and accessories.  These will have all the details of installation along with any recommendations for continued airworthiness.  if you recall this was what we saw when Rotax released the new Rotax branded spark plugs.  The information for the new plug gave us the data for the plug along with the torque values and service intervals.  At that time they also called out the NGK data and called out the tooling required and the like.  Currently all reference to NGK no longer exist within the newer manuals as they phased out of NGK.  (it was NGk refusing to sell for aircraft applications) 

    So while i agree you may wish to change a boost pump there is no Rotax requirement to do so.  Purely from a safety standpoint you still have a mechanical one on the carbureted engines, except the 914 that has 2 electric.  The iS versions all have 2 electric.  They are not replaced until overhaul.  The boost pump normally is used on take off and on landing at the very least.  Some OEM recommend they run all the time, this would be something the OEM would call out based on their verification of the fuel system.  If that is the case perhaps replacement at 50% time would be prudent?  I don't think that time itself is that relevant unless it was a design that was based on a diaphragm internally that would be subject to age.  Most boost pumps are vane type and do not have internal rubber parts.  The mechanical have diaphragms that have atmospheric pressure on one side so are subject to not only the fuel type but the atmospheric degradation, therefore the 5 year limit regardless of hours. 

    Certified aircraft under part 23 must provide a fuel pump(s) that produces enough fuel volume to be at least 125% of total required.  (for each pump) This is very important for those who might use dual electric systems.  Loss of a single pump should not compromise power in any situation.  

    Cheers

    Cheers


    Thank you said by: Peter Lutz

  • Re: Where to buy 5 year rubber replacement kit

    by » 5 weeks ago


    Hi RW,

    "Most boost pumps are vane type.........."

    Are you sure? No experince but this sounds more like something that might be found  in the primary (not Boost) fuel supply for a fuel injected engine?

    In Australia, I think you would find that the majority of carbureted engines, will use an original  Facet or copy, as the Boost pump.


  • Re: Where to buy 5 year rubber replacement kit

    by » 5 weeks ago


    Hi Sean.  The automotive Facet is indeed a simple interrupter type pump.  This design has inherent "pulse" patterns and you may see this in your fuel pressure as oscillations of the pressure.  The standard design type is also called a "cube" pump.  

    Generally in electric Rotax aviation pumps are mostly vane type,, all the type 914 and injected Rotax engines use that design type.  Far more expensive but deliver smooth fuel pressure.  

    Cheers

    attached find an example of small vane type.

    39473_2_Pierburg simple vane pump.jpg (You do not have access to download this file.)

  • Re: Where to buy 5 year rubber replacement kit

    by » 5 weeks ago


    RW,

    Does the vain pump fail open ie does it stop the fuel flow when its not going?


  • Re: Where to buy 5 year rubber replacement kit

    by » 5 weeks ago


    Hi Sean

    You should always use a one way check valve with it.  Attached is from a 914 with 2 pumps and you can see the required check valves.

    Cheers

    39475_2_914 pumps in series.jpg (You do not have access to download this file.)

    Thank you said by: Sean Griffin

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