I have a question regarding all my practice with dead sticks. It is not that I want to be practicing, it just seems that I shouldn't have to have so many. This is my second plane and when coming down from a high altitude, my plane tends to die. It is not from lack of fuel in the tank but because the clunk is not picking up the fuel from the front of the tank. Is this just something that people deal with or is there something wrong with my setup? I see others go way up high and dive all the way down but their engines don't die.

Thanks,

J

The clunk is not SUPPOSED to go to the front of the tank. And that is rarely the cause of dead sticks.

Are you sure that it's not being caused by a bad idle?

It could be that once air is flowing, the carb may pick up some turbulence and not get a proper mixture, or maybe the low end is just set wrong, and once it idles for a few minutes while it's coming down, it loads up, or leans out.

but even when I don't idle back it gives me the same problem. it doesn't always happen when it a dive. If I fly and an increased decline for an extended period of time then it will die. There seems to be a point where the incline is too steep. If I pass this for more than about 15 to 20 seconds, it will die. Perhaps I need to do more testing to see how long it takes before it dies.

j

20 secs is a pretty long dive. If you meant 20 sec gradual descent, that would be more realistic.

Maybe his clunk line is too stiff & maybe a bit long. If the clunk is poking essentially straight out from the bung, it could prematurely expose itself & let the engine run dry.

More likely, as Minn says, the engine tuning is not quite right.

Maybe the clunk line has a hole in it and it draws air when the bulk of the fuel goes forward in the tank during a dive.

The fuel doesn't go forward in the tank in a dive. Inertia keeps the fuel in the back of the tank. I agree with Minnflyer, it sounds like a tuning issue. It also wouldn't hurt to check the tank. A clunk stuck forward in the tank could cause the same thing, especially if it dies during a climb.

Hope this helps

Ken

Thanks for the advice.

The tuning could need a slight adjustment, but doesn't seem to be the major cause of the problem. The engine doesn't die in a climb but the line being too stiff sounds most likely. I did change out the tubing that came with the tank for that reason. I put in some that seemed more flexible to me. I haven't had any problems with it coming forward in the tank but perhaps it is still not flexible enough. Is there some kind of fuel line that is better than another and more flexible?

Thanks again,

J

Actually, you want the line stiff enough so that it WILL NOT go to the front of the tank. Use a piece of brass tubing in the pickup line so that it can't go forward to the front of the tank. See diagram

Ken

Use a clunk that has enough mass to easily hold the line to the bottom of the tank but not quite touching the back of the tank and regular medium silicon fuel line would be fine too. Also use the section of brass line as Ken suggested. We've all assumed that you have your muffler pressure line attached properly?

it sounds to me like your low end is a little to rich and is loading up. in a climb it will tend to lean out a little and sound a little better and not want to stall. make sure the idle speed is set properly and not too low.