running a tank dry

I want to run my tanks dry in flight to check the fuel gauges and fuel computer. Im running a injected xp360 in a rv7 airframe.
Anything I should look out for ? Advice ?
EJ
RV7

rv72004 said:

I want to run my tanks dry in flight to check the fuel gauges and fuel computer. Im running a injected xp360 in a rv7 airframe.
Anything I should look out for ? Advice ?
EJ
RV7

Click to expand...

I'm assuming you're doing this one tank at a time, but even so, I'd be wary of starving the FI and not being able to restart before a short flight becomes a long drive or a sudden stop.

No substitute for real-world data, but I would do all this on the ground. Lift the tail so the ship is in level flight attitude, then pump the tank dry with the systems on. Based on flow rate (if you can trust your sensor), you should be able to test your gauges and computer. If you don't trust your sensor, pump a known quantity of fuel through it and time it.

rv72004 said:

I want to run my tanks dry in flight to check the fuel gauges and fuel computer. Im running a injected xp360 in a rv7 airframe.
Anything I should look out for ? Advice ?

Click to expand...

I would do some forced landing practice before I did this test.

Have a test card, with a very clear list of items you will observe and record, and a list of actions to take when the engine quits, and another list of actions to take if the engine does not restart. E.g. note rpm and fuel pressure while engine is running normally. Observe the fuel pressure during this event. Start a timer at the the first obvious change in fuel pressure, and note the time at the first event that would be noticeable if you weren't staring at the fuel pressure, and the time when the engine quits. Wait for a suitable time delay to simulate a surprised pilot (three seconds is a typical assumed time delay), then take whatever action you have planned as the response to this event (probably just change fuel tanks). Note the time when the engine restarts. If the engine does not restart within a few seconds, then select the boost pump on, turn towards the airport, and adjust speed as required to ensure you make the field. If the engine still does not start, declare an emergency and do your forced landing drills.

I'd do this at a suitable altitude, circling over top of an airport with a suitably long runway.

My experience of running an IO-360 angle valve motor out of gas (forgetting to turn to acro tank before turning upside down in an Extra 200) is that the prop - c/s MT - kept spinning and the engine started just as soon as I turned right way up, found the fuel tap and swapped tanks - 5 seconds max.

Pete

Not a problem

I have run a tank dry regularly with my -7 running an IO-360 when using the tip tanks.
There need be know drama.
The prop will keep the engine turning, whilst you change tanks.
Boost pump on reduces the time for the engine to catch.
I usually reduce to about half throttle to prevent the gov/prop from over working when the engine relights.

The first sign of the impending fuel starvation is on my GRT Engine Monitor. The fuel flow is seen to reduce rapidly, well before the engine hesitates.

Now. Lastly, when it all happens, don't forget to read the fuel levels and Fuel Gone and write them down.

Pete

Thank you very much, Peter.

My thoughts exactly. Check out Deakin's articles on www.avweb.com for more info. He strongly urges you to do just that.

CJ

Thanks for the replies. Now just to pluck up the courage to go do it.

EJ
RV7