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Hi All,

Here is a little test you could do with your plane to let you know how it will run without a fuel pump. I have a Flight Design CTSW high wing and wanted to see if it would gravity feed or would die without the pump. I disconnected the pump and joined the two hoses. I started the engine and ran it at 4900 static rpm on the ground, which equates to 5300-5400 rpm in the air, for about 30 minutes. It never coughed or sputtered. This test leads me to believe that if I lost my fuel pump the engine would still run until I landed. Interesting result to say the least.

Now the question begs; If the pump were to go out in flight and you didn't have a fuel pressure gauge how would you know? I don't have an answer.

The results may be totally different on other aircraft due to plumbing and of course high wing verses low wing. It is a good test and may or may not give you peace of mind.

If anyone tries this little test which is very easy I would like to know the results, including any low wing aircraft.

p.s.
If you do this test, then after the lines are off the fuel pump hand prop the engine a few times with a rag by the fuel pump to get any remaining fuel out so it doesn't squirt all over when you start the plane. It might be nice to get some real data on this.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

  • Re: Testing - No fuel pump

    by » 13 years ago


    great idea, I have a Highlander by Just Aircraft and have been told it would run in the event of pump failure but as you say peace of mind. I recently noted alittle gas leaking at the base of the fuel pump (55 hours on the engine 912 uls) and will do the check when I replace it. Thank you Arnie Koriakin

    PS. I'm alittle confused where to place the drain tube. Did someone submit pictures and I missed it?

  • Re: Testing - No fuel pump

    by » 13 years ago


    Hi Guys,

    (High Wing only)
    The first fuel flow was a little flawed. The pump had been removed from the circuit and hoses joined, but that isn't how we fly. Today I removed the entire pump off the engine and left the hoses attached to allow fuel to flow through the pump. I ran it on the ground and at anything over 4100 rpm it would sputter and at 4800-4900 it was really rough. At 4000 rpm it did run and without any issues. That does mean you could still fly to a landing spot and use throttle to land. Once down I think your stuck.

    So the news is still good, just not as good

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Testing - No fuel pump

    by » 13 years ago


    G`day Roger
    This is just a thought,but one could install a bypass line (with a check valve)around the fuel pump. Should the pump fail in flight the fuel should flow similar to your initial test. This only applies to high wing a/c`s of course.

  • Re: Testing - No fuel pump

    by » 13 years ago


    Hi Don,

    I theory it would work, but you would need additional testing on the ground and in flight and I'm sure it isn't anything Rotax or a plane MFG would be willing to endorse. I did the original test to see what would really happen and didn't want to wait to try it in the air for real. It was also done to put to rest a lot of talk on both sides of the fence to see if it would work.

    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


    Thank you said by: Don Hudgeon

  • Re: Testing - No fuel pump

    by » 13 years ago


    This doesn't really apply, but I fly a 1946 ercoupe that is fed from a 5 gallon header tank just above the engine. there is an electric pump that pumps fuel from the two nine gallon wing tanks to the header tank to keep it full. The beauty of the system is that if the electric fuel pump fails, the header tank will keep you going for an hour. There is no mechanical pump, the engine is always gravity fed.

    Bill.

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