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In section 3.5 (Engine run-up) the Rotax 915 iS Operator's Manualsays, in addition to the Lane and Ignition check, a Wastegate and PCV check should be accomplished. It says this should be done at full WOT and over 4700 RPM! Does anyone actually do this as part of a routine pre-flight run-up? 

It also says, "If possible the PCV Check and the Lane and Ignition Check might be combined in one check." However, I note that it says to do the Lane & Ignition check at 2500 RPM.

Maybe this is why the Sling TSi manual says to do the run-up at 4000 rpm, perhaps a happy medium to accomplish both checks simultaneously? Seems like in both checks you're just turning off lanes and checking indications remain within parameters.

Does anyone have more guidance or info on this check?

Thanks!

  • Re: Wastegate and PCV check?

    by » 5 weeks ago


    So what's supposed to happen at 4,700 rpm that would indicate a successful wastegate or PCV check? I do a modified WOT check as part of my run up to check for engine smoothness, watch the numbers, especially temps and pressures, and look for warning lights. Then I reduce rpm to 2,500 for lane checks, then 2,000 rpm for fuel pump checks. I say modified WOT because at 4,300 that 915 starts to drag my gyroplane across the pavement!

  • Re: Wastegate and PCV check?

    by » 5 weeks ago


    Michael Baker wrote:
    So what's supposed to happen at 4,700 rpm that would indicate a successful wastegate or PCV check? I do a modified WOT check as part of my run up to check for engine smoothness, watch the numbers, especially temps and pressures, and look for warning lights. Then I reduce rpm to 2,500 for lane checks, then 2,000 rpm for fuel pump checks. I say modified WOT because at 4,300 that 915 starts to drag my gyroplane across the pavement!

    Good question! All it says is to "Check engine instruments (Warning Indicators and Operational Limits) and ensure compliance with the operating limits" and check the Lane lights. So basically, you're looking at the same things as you would on a Lane Check, hence the reason why you can combine them.

    I guess you need the higher RPM or the wastegate or PCV doesn't get "checked?" I guess I'm wondering if WOT is really necessary for that.


  • Re: Wastegate and PCV check?

    by » 2 weeks ago


    Nobody has an answer to this? I emailed both Rotax and my airframe manufacturer - no reply.  @Rotax-Owner?

     


  • Re: Wastegate and PCV check?

    by » 2 weeks ago


    I do not have any experience with the 915is, but I once stayed ... ... 

    The 915's Wastegate is Pneumatically operated. (Unlike the 914's Servo/Cable control system.)
    The Waste Gate controls the Manifold pressure.
    The PCV (Pressure Control Valve) controls the Wastegate.
    Under common surface conditions, and near WOT (>4700), the WasteGate should be Partially Open; limiting any OverBoost.

    I would agree that a reasonable way to combine all the engine checks would be to ...

    Power up to ~5000 rpm.
    Then turn OFF One lane and One Fuel pump.
    During the 15 second wait, Monitor the MAP and Fuel Pressure for Normal Readings and note that neither the LANE nor Other Warning Lamps Illuminate and that the engine continues to operate Nominally.
    Repeat for the other Lane and Pump.

    It should be plenty warmed up by now, so finish up with 5 seconds of WOT just for good measure.


    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Bill.Hertzel@Yahoo.com
    Clicking the "Thank You" is Always Appreciated.


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