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nose up test

Old 08-16-2010, 08:14 PM
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joco1
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Default nose up test

When you do the nose up test,and it runs fine when you raise the nose but it dies when you point the nose down ,what does that mean?
Old 08-16-2010, 08:46 PM
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d_bodary
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Default RE: nose up test

A: You flooded it
B: You uncovered the clunk
Old 08-16-2010, 09:02 PM
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joco1
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Default RE: nose up test

thanks!
Old 08-17-2010, 07:09 PM
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joco1
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Default RE: nose up test

The plane im flying is a omp profile with a 55ax installed on it ,tonight when i was flying i did a few loops and a few rolls and then it just didnt sound right so i landed and could see alot of bubbles in my fuel line! What causes this and where do i need to start to fix it?
Old 08-17-2010, 07:21 PM
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Default RE: nose up test

Fuel is foaming or air leak in fuel line.
Old 08-18-2010, 08:05 AM
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rlipsett
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Default RE: nose up test

fuel line air leak might also be inside the tank. Best solution is to replumb the tank with new lines inside and out it is only about a dollars worth of tubing. make sure you have foam under the tank but not compressed hard and rigid
Old 08-18-2010, 09:55 AM
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SeamusG
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Default RE: nose up test

Hey glow experts out there. What is the goal of doing a full throttle nose up test at the starting bench? What are you looking (or hearing) for? How long do ya hold it up?
Old 08-18-2010, 10:12 AM
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Default RE: nose up test

You are listening for the engine leaning out. With most standard fuel set ups, when you hold the nose up the engine will lean out. What you want is the max safe lean condition with the nose up and the engine running good in straight and level position. So if your plane is known to lean out a bunch, you really want to set the mixture with the nose up.
Old 08-18-2010, 10:14 AM
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Chad Veich
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Default RE: nose up test


ORIGINAL: SeamusG

Hey glow experts out there. What is the goal of doing a full throttle nose up test at the starting bench? What are you looking (or hearing) for? How long do ya hold it up?
The goal is to determine if the engine is too lean. When you hold the nose up the engine will lean out slightly due to the fact that the engine is having to work harder to draw fuel due to gravity. If the needle setting is too lean the engine will lose RPM (sag) or quit completely when the nose is held up. Ideally the needle should be set just slightly rich when the airplane is level so that it gains a few RPM when held vertical. You should only have to hold it vertical (at full throttle) for a 5-10 seconds to figure out all you need to know. That's my .02 cents anyway.
Old 08-18-2010, 10:37 AM
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SeamusG
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Default RE: nose up test

Gotcha - a friend (2nd plane newbie) at the field held his 4Star40 w/ OS 55 AX up at full throttle (13K rpm). He held it up for 5 - 10 seconds. No change in rpm. Following the posts I'm going to recommend that he richen the high speed needle a click or 2 then retest.

Thx for the input.
Old 08-18-2010, 11:36 AM
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ARUP
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Default RE: nose up test

Also, when the airplane's prop 'unloads' while flying the mixture will lean out a little. You definitely want the mixture slightly rich in level attitude.

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