Hi,

My build manual (Sling 4) specifies to cut a section out of the tube leading to the right carburetor, silver solder on two 5-barb fittings and use rubber hose to insert a fuel flow sensor. Do people think that's a good way to do it? A better, easier way? Haven't done silver soldering and don't have the equipment or materials to do that.

Also, do people wrap those tubes leading to the carbs? I think my manual shows them wrapped in fire sleeve. Best way to do it?

Thanks!,

Craig
  • Re: 914 Fuel Flow Sensor

    by » 4 months ago


    Nobody has a fuel flow sensor in their Rotax setup? I assume people do, so I'm wondering where in their system the sensor is inserted.

    Thanks!

  • Re: 914 Fuel Flow Sensor

    by » 4 months ago


    Placing a sender in only one carb fuel line will only measure half the fuel flow.

    The correct installation would be to use two senders, one in the main feed flow and one in the combined return flow and connect the senders through a Fuel Flow Differential module to the gauge.
    The installation is the same as on the fuel injected engines.

    Because there is no mixture control, a Flow monitor is only an optional/informational instrument on a Rotax engine and is not commonly installed.

    Fire sleeve is normally installed over ALL Fuel lines.
    It just slides on.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    whertzel1@yahoo.com
    Clicking the "Thank You" is appreciated by all.

  • Re: 914 Fuel Flow Sensor

    by » 4 months ago


    Bill,

    It seems having a fuel flow info is useful in any case, right? How else would you know it unless you have this transducer?

    Thanks,
    Craig

  • Re: 914 Fuel Flow Sensor

    by » 4 months ago


    Well, I know the engine burns about 5 gph at 5500rpm and 4gph at 5000 from experience.
    So I know that when I have 5 gals remaining I have an hour to get on the ground and when I get down to 2 gals, I better have the runway in sight.
    Does knowing I am burning precisely 4.8 gph really help anything?

    If I was an hour out over the ocean with 4 gals remaining, I am not going to make it.
    And I do not have the option of leaning the engine to try to stretch it.
    So it would be useful in knowing exactly when, and how far offshore I am going in the drink, but the results are going to be the same.

    My opinion is that is is nice information to have but there is nothing you can do with the information.
    And the same information can be obtained with a fuel gauge and a watch.
    It is a convenience item, Some people really like them.

    I suppose it depends a lot on your fuel gauge.
    Mine is digital and has 6 calibration points and 27 levels of indication.
    So I have a high confidence level that I know how much fuel is remaining accurate within 0.7gals.
    I also suppose that if the fuel gauge only indicated to the nearest 1/4 tank I would probably have a different opinion.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    whertzel1@yahoo.com
    Clicking the "Thank You" is appreciated by all.

    Thank you said by: Craig E Maiman

  • Re: 914 Fuel Flow Sensor

    by » 4 months ago


    Actually you can do something with the knowledge of fuel flow; by throttling back significantly you can increase your range. So if by using accurate fuel remaining and fuel flow information you calculate that you won't make your destination by a small amount, you can throttle back and possibly get there. There are articles in the flying magazines on how to do this and how much help it will do.

    Thank you said by: Craig E Maiman

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