Re: Run-in and angle test

OK sounds like you guys are says this may be normal... the tank was about

75% full at the time. The Klunk may have stayed at the top (back) of the tank... Hard to tell... a closed off vent would cause this would it... maybe these planes are really configured to take extended periods on a >30 deg nose down run... If you think its something to worry about let me know... otherwise I'll continue to finish off my fine plane trim and ready her for the airfield...

Spent most of the morning running my new GMS .47 in. No problems and its

> running good. One question though... It will run smooth all the way to > vertical... it will run for about 15 sec at about 30 deg down and then quit. > Runs ok at 20 to 25 down, but get past that and its only a matter of time > before it quits...Whats causing that??? I think I remember some posts a > while back but don't recall the answer... I think it may be the fuel tank > vent... based on the level of fuel in the tank, at about 30 down the vent > was covered... or maybe I just flooded the engine because the tank was above > the carb? Anything I can do to fix this problem? Thanks ahead of time > >
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You are probably OK with that. You seldom run that long at full throttle at

30 deg down! And the fuel is sloshing around quite a bit so it would likely go a lot longer.
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Paul McIntosh

Hi Newbie, As the other guys have said, pointing the plane downwards will uncover the clunk in the tank when the fuel gets low enough and/or the angle gets great enough. When the fuel in the clunk line is used up, the engine will stop. The clunk should *never* fall forward.....doing so will likely kink the fuel line and stop the flow anyway, resulting in the same thing.....engine stopping. A covered vent line won't make any difference......there will be pressure coming from your muffler and will keep the line from filling up anyway.

When you're flying, it's not appropriate to have the throttle wide open when you're on a downline, unless you're aiming for the dirt :-) Just about any engine will maintain fuel in the line for quite a long time at idle, particularly if the clunk is not totally uncovered the whole time. As has been already said, you'd have to be *quite* high to be able to maintain a full throttle, high angle descent for 30 seconds :-)

It normally goes something like this:

Unless you've got a really tight ship which is designed for speed, you just don't do it :-)

Good luck and good flying to you!


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