How much arch is supposed to be in this line?



Just enough to keep it off of the engine? Manual didn't say and the piece of fuel line the manual said was in the box was not so I made up a line.

somegeek

I wouldent do it like that, I would have a str8 line with no angle like you got it. I would also get a white clear isntead of blue so I can see if there are bubbles in the tank or somewhere going in the carb if there should be a problem but thats fine. I would cut it a lil shorter to make it straighter.

DON'T make it straight, it will rub on the engine and possibly cause all kinds of fun problems. Keep it just as you have it, looks perfect. That is fairly light blue, if there are any air problems you still should be able to see the bubbles fairly easily.

As short as possible but make sure it does not rub the engine or you will have wear and eventually a hole. Also, make sure that any vibration does not cause it to rub the engine.

Actually, you can do it either way and it won't matter. The attached picture is how it looks fresh from the factory. You will noticed that the line is straight, but it doesn't touch the side of the motor even if it is straight. Even if it does touch the motor, there isn't enough movement of the fuel line itself to cause any problems with rubbing. On OS motors with a remote needle valve there is a slight delay in the motor changing when you make adjustments of the needle valve, and if you increase the length of this line that delay will increase slightly.

But as I said before, you can do it either way with no problems at all.

Hope this helps.

Ken

I tend to disagree with the delay in throttle, due to hydraulics. If I go to the basement, close a valve 25 ft. away from the sink. Open the valve at the sink, nothing will run out. Go back and open the other valve 25 ft, away, water will flow as soon as you open the valve. Water at the valve is pushing a solid column of water from valve to sink.

I would have to agree with RCKen... The movement with start as you said,
But what ever change you make will show up when it gets to where its
going.. And if it's further away, it'll take a bit longer

On my engines I find the delay virtually undetectable. Flypaper is correct IMO about this being one of the basic laws of hydraulics which would apply to a liquid fuel line. If it was in a gaseous state, that could be another matter. Any delay seen may just be that needed for the crankshaft to achieve the new speed due to flywheel effects.

When you are dealing with a fluid in a closed line you need to think of it like a solid object, such as a stick. When you push or pull on one end, the other end is going to mimic the movement without delay. To expect otherwise is not logical to me

MMmm I guess bruce88123 & Flypaper 2 may be on to something
I guess your just moving a volume of liquid and it should be almost
instant. But I do have some engines that take that little bit of time for
the change... Guess its just the engine stabilizing the new settings....
This forum is great.... Always picking up something!!

Flypaper & Bruce, You are both absolutely correct about the column of water. As soon as you open the valve at one end the fluid will start flowing at the other end... BUT, if you change the amount of fluid flowing through that column you do have to wait for change to happen at the far end. This is what I am referring to. I will clarify in saying that they delay isn't very long (a second if that much) but there is a perceptible delay when you make a change.

Ken

I could still be wrong but this is what I was taught about hydraulics in college and A&P school. Most important is to keep it cool and air bubbles out.

Sorry ken, you and I are going to disagree on this one. The laws of physics don't allow for your interpretation IMO.

I made a further search and found this Hydraulic theorem:

At any node in a system containing incompressible fluid, the total volumetric or mass flows in must equal the flows out, less the change in storage.

Since there is no change in storage (the line stays the same size) what flows in must flow out. No more/no less.

GIGO, or in this case: fuel in=fuel out

[link]http://www.jettengineering.com/faq.html[/link]


7th question down.

So since the delay would be .0003 sec for a foot and we have @ 2 inch line it would be more like .00005 sec. Then allowing for the "slightly longer", I'll double that and have a whopping 0.0001 second. I'm sorry, I don't think any of us could percieve that time span very well and that it would/should be considered instantaneous.

i don't think if it were 1/2 inch longer it wouldnt matter,you got an opening and an exit in the line they are the same size.you can only push an x amount of fluid through an opening as fast as it would be allowed.hydraulics is resistance to flow.we pressurize the tanks and I'm not sure but would assume 1 to 2 psi.so we have fuel line hydraulics or positive feed to the carburetor.i would plumb my fuel lines as neat as i can but honestly don't think if a line were slightly longer it would affect anything but ugliness....and replacing a pice of 2 inch fuel line every 10 or 12 flights isnt a bad idea....happy flying