Walther

My Feedback: (1)

I have an airplane that I built 20+ years ago and could never get the engine to run correctly because of the the way the fuel system is. I was going to convert it to electric but I thought perhaps one of you had used a pressurized fuel system in the past.

daveopam

My Feedback: (9)

I have a Cline regulator on a 72" Yak. I did mine so the tank could be on the CG. It is a pretty straight forward and easy set up. The regulator and two fuel dots ran about $75. Go to www.billsroom.com I think it is. That is who makes them.

David

rexracer

I'll second the Cline. The engine will run great, and consistantly throughout the tank. I may eventually end up with a Cline on everything I fly.

Flyboy Dave

My Feedback: (21)

....does your engine have a nipple on the muffler to pressurize
the fuel tank ? I Think most all modern engines use fuel pressure
these days....but I'm sure someone will point out an exception.

Another option is a bladder tank, if you cannot pressurize the fuel tank.

FBD. [sm=teeth_smile.gif] (edited for spulling)

Hobbsy

My Feedback: (102)

Hey Dave, houz come you cain't spull.[8D]

Flyboy Dave

My Feedback: (21)

....Yo, Hobbsy....what sa' matter with blatter. [sm=red_smile.gif]

FBD. [sm=teeth_smile.gif]

Iflyglow

My Feedback: (79)

If you install a Cline system the way the instuctions recommend, you will have no problems at all.[)][)]

ShortField

I use a one way check valve on my exhaust line to the tank and both the pick up line and the pressure line for the muffler have a clunk on them and the vent line has a plug in it. It's called a uniflow system. It keeps a constant flow of fuel to the carb. You will also need to use a fuel line clamp of some kind because when you stop your engine the fuel keeps pumping into the carb and you can get a hydro lock real easy. When you stop your engine you need to crimp the fuel line or pull the plug from your vent line to release the pressure. I use this system on my helicopters and my planks. [8D]

Sport_Pilot

I would suggest that you remove the check valve from the muffler line. It may also cause the idle to lean out and quit after a long period of idling.

ShortField

I've been using this system for 3 years now if you remove the check valve and your in flight at full throttle and you back off the throttle, the pressure in the tank will back up fuel into the muffler. You need to have a carb with at least 2 set screw, or 3 set screws, low end, middle, and high end. You will have to re-tune your engine after putting on the check valve and plugging the vent line. People at my field think I'm running a pump on my engines. [8D]

ShortField

Sport_Pilot
I can idle my engine all day and it won't lean out because there is a constant pressure on the fuel, you will have to re-tune your engine because you now will have pressure going into the carb. Plus your engine will NOT lean out at the end of your tank unless you run it empty. [)]

Sport_Pilot

I don't know what you are running and there may be exceptions to what I am going to say, though I do not know what. At idle the muffler presure of most all engines is very low. That's ok because the carb is providing more suction. But if you put a check valve without a regulator then the check valve traps the muffler pressure and eventually that pressure will run out. It may take a while, and that while may be minutes, so if you don't idle for more than a minute or two (or even longer) you would never know it. But removing the check valve also eliminates the problem of fuel continuing to squirt into the carb on shut down. IMO I'd rather have a little fuel go into the muffler, it does no real harm. If you have a long enough line and the carb is well below the tank you will get little to no back flow of fuel into the muffler.

Walther

My Feedback: (1)

Shortfield,

What is the purpose of the clunk on the pressure line?

Sport_Pilot

The uniflow system keeps the fuel pressure even from full to empty. To do this the pressure line must be at the same level as the pickup line. So you mount a clunk on the muffler pressure line and it is kept shorter than the pick up clunk so that the bubbles are not picked up. Fuel backflowing into the muffler is not usually a problem. Muffler pressure is usually less than several inch's of fuel so if the muffler is no closer that that then there will not be any backflow. If it is then maybe an inch or two of fuel backflows in. I have never had a problem with it, just a small puff of smoke when you chop the throttle.

ShortField

That"s a good explanation Sport_Pilot I've just be commenting on the system I've been using and it's been working for me About the check valve, it only holds so much pressure and won't blow any fuel lines off or burst the tank, and when your engine idles it does build up pressure and the carb does not have to work to get fuel to it once the pressure is built. That's why you need to re-tune your engine. I had to lean out my low end needle because of the pressure, once set, it will idle and not lean out [)]

Iflyglow

My Feedback: (79)

The whole idea of the cline regualtor is that it regulates the fuel to carb on a demand basis only, and never changes from full tank to last drop nomatter where the tank is located in the plane. There is no way that the even flow set up would even begin to work as well.[)]

daveopam

My Feedback: (9)

I'll second what Moterman said. Plus with the cline there is no siphon problems with inverted applications. If the system has a drawback it is that you can't choke the engine by holding your finger on the muffler. I can't reach the carb on mine and have no way to choke it. I have to crank it 30 seconds or so with a starter to get the first fire of the day.

David

ShortField

I agree with you guys the cline system works very well. For 60 bucks you can't go wrong. I hope that you were not thinking that I was knocking the Cline system. The subject of the thread is "Pressurized fuel systems" I was only giving my 2 sense worth

Walther

My Feedback: (1)

ShortField,

I did look at the Cline regulator but I am not sure it would work with a .15: I had a Robart pump that had a pressure tap on the crankcase and an OS FP .15 on it, and that did not work so that is why I asked about pressure system.

daveopam

My Feedback: (9)

I thought it was some good info Shortfield. It does sound a little more complex than the Cline though.

David

Sport_Pilot

If the tank is mounted close to the carb. And the carb is somewhere between the top and bottom of the tank it will work as well. But if not then a Cline regulator will work better. If the tank is mounted low than the Perry pump may work as well also.