Experimenter

April 2013

Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.

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Hangar Debrief safely. Use a hole, ditch, or whatever you can find to lower the tail as much as you can. The rest you can do by blocking up the mains. Be careful! Get plenty of help! Repeat the fuel flow test as before. Do not run the engine during this test. Record the results in your builder's log. Note that your unusable fuel quantity may be more in this configuration. The maximum-descent test is similar to the previous tests but with the nose down. Again, you need to determine the down angle, which should be the angle in a full-flaps, power-off descent at the top of the white arc (Vfe), or if no flaps, a power-off descent at the top of the green arc (Vno). The maximum slip test cannot be conducted on the ground; it must be done in flight. While flying over an airport at a safe altitude, burn off fuel until the fuel remaining equals the amount of fuel needed to sustain 75 percent power for 45 minutes. Then place the aircraft in a landing configuration and slow to 1.3 Vso. Consult with the airplane designer regarding any limitations on slipping with flaps extended! Perform a maximum-rudder-deflection slip to the right and hold for 30 seconds. Then repeat to the left. During this test no loss of fuel pressure or engine power should occur. If it does, land safely, add fuel, and repeat the test until a minimum safe amount of fuel can be determined. Record results in your builder's log. As before, carefully position the plane at the proper down angle. Take care to avoid damage to the aircraft or injury to people. Conduct the fuel flow test as before. A fuel flow of 25 percent of maximum is sufficient for this test since we are testing a power-off descent. It is our hope that the manufacturers of aircraft kits will perform these tests for you and make the results available to their customers. If you then install your fuel system exactly as per the kit manufacturer's recommendations in every detail, you could then dispense with all of the tests except the level-flight test. Exactly the same means even to the fuel flow sensor and the venting system, especially the venting system. If you delete any of these tests, you should note the reason why in your builder's log, citing manufacturer's testing where appropriate. Do not run the engine during this test. Record the results in your builder's log. Until this information is available you will need to do all of these tests before first flight and after any fuel system As before, consult the designer for this angle, or measure the angle in a similar plane, or assume 10 degrees and verify it later in flight testing. You do not need to add an extra 5 degrees for this test. Disconnect the fuel line at the carburetor or fuel injection servo for the fuel fow tests. 48 Vol.2 No.4 / April 2013

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