OldRookie

My Feedback: (13)

Has anyone successfully run a Cline regulator with an OS 46FX?
I have been having problems. I put it between the needle valve and carb, and also rigged up a needle valve so I could go from the Cline to the needle valve, and to the carb, trying not get the Cline too far away.

Greg

RVman

Are you using crankcase pressure?

OldRookie

My Feedback: (13)

Yes...Everything is set up just as the instructions specify.

Greg

prgonzalez

When using the cline regulator, you need to open up the LSN and let the regulator deliver the right amount of fuel.

OldRookie

My Feedback: (13)

I guess it would be better if I stated what I have already tried.
I am using the Cline regulator on my Venus. The tank center line is over 1" high with the engine inverted. I was having trouble with the engine flooding. On all outside maneuvers the engine would almost kill. It had some glitches in the engine at a lot of different times.
The construction of the plane doesn't lend itself well to a tank location change.
I put the Cline in and the first session with it, I couldn't get it rich enough where I felt comfortable with it. I had the needle valve out 9 turns, and still didn't slow the engine. This was with the Cline between the needle valve and the carb, and just hanging off the fuel tubing. I called Cline and he told me to screw the idle needle out about 1/2 turn.
Having the needle valve screwed out made it so I could richen the engine quite a bit. I got the idle needle set so I had good throttle response, and the top end was good. Now the mid range was too rich. If I would fly full throttle I could climb out of sight, do outside loops, tumble snap, and the engine wouldn't sag. When I would fly straight and level at half throttle the engine would load up.
Next I figured there was atmospheric pressure problems in the cowl, so I ran a tube from the metal regulator cover to the inside of the fuselage, like I do with my gas plane. This had no affect on the rich mid range.
The next thing I tried was to put a needle valve between the Cline and the carb. This was worse than the way I had it previously. I had the needle valve open 5 turns and still could go further. The low end was poor, and would load up. During verticals the engine would sag. Even with keeping all fittings as close as possible, I think the Cline was about 1-1/2" away from the carb. Any time I would come out of a loop type of maneuver the engine would sag right at the bottom, and speed up to normal in a couple of seconds.
That is where I am at now.

Greg

MJD

My Feedback: (1)

"I put it between the needle valve and carb"

That doesn't sound right to me.

"..go from the Cline to the needle valve, and to the carb.."

Makes more sense to me.

Do the instructions really suggest putting it between the NV and carb? I can't see how that would work - why would you throttle flow to a demand regulator? Seems to me the right position is as close to the NV inlet as practical. The engine can draw from the NV to the carb just fine in any attitude, if the NV sees no change in fuel head - I thought that was the idea.

"When using the cline regulator, you need to open up the LSN and let the regulator deliver the right amount of fuel."

The Cline regulator is a demand regulator, not a pressure supply/pump. You are essentially tuning the engine as if it is on suction but the fuel head never changes. You'll likely have to open both needles since they were used to dealing with a bit of muffler pressure before.

MJD

MJD

My Feedback: (1)

We must have been typing at the same time, so my reply doesn't take into account your latest comments.

I've seen it suggested elsewhere that referencing the pump to muffler pressure rather than to atmospheric might help those sorts of issues.

MJD

OldRookie

My Feedback: (13)

On the 46FX in case you didn't know, the needle valve is at the rear of the engine. By mounting the Cline before the needle valve the Cline would be a good 3" from the carb. Cline said 1-1/2" absolute maximum.

Greg

David Bathe

I've done some experiments with both Clines and perry's and come to the conclusion that they both prefer larger engines. The larger the better, the smaller they more troublesome they can be.
With any sort of Pressure (or Pump) delivery there is always some type of trade off. Normally, a rilthy rich mid range. Again, this problem seems to lessen with larger engines.
I've tried the Cline between the carb and the needle and before. I prefered the latter (that was on a .91FX with a CG mounted tank) but as stated, it changes form engine to engine... or more correctly, from carb to carb.
I basically gave up, moved the tank back to it's normal position and delt with the small inflight trim changes by adding a simple 3 position flight condition (tiny elevator movements) to one of the switches... like that was complex compared to fiddling with Clines and Perry's!!!
That doesn't help your problem though.
If everthing is OK except the rich mid range, I'd tend to work on from there. I remember always having to screw in the LSNV almost all the way! A great deal further in than normal to help (you can't cure it completely) the mid range.
Then reset the idle possition using the ATV.
BTW, what aircraft is it mounted in?
Good Luck.

freakingfast

My Feedback: (3)

Greg
Never put anything between the carb and needle, even a fuel filter. Put the regulator as close to the remote needle as you can but more importantly at the carb's elevation. I like to use no less than about 1 1/4" of fuel line to help isolate the regulator from the engine vibrations. You can position the regulator closer to the carb and let the fuel line double back to the needle. Don't mount it to or make contact to the engine, engine mounting rails or a badly shaking cowling, vibration will mess with metering or shorten the life. These regulators do work at bit better with a carb mounted needle.
Your needle setting should be closer to stock in this configuration. You are using case pressure right?

OldRookie

My Feedback: (13)

David Bathe, Freakingfast....The plane that I have this set up mounted in is the GP Venus 40. The cowl of the Venus is kind of tight, and it is impossible to put it in there without the regulator touching either the cowl or the engine. The instruction sheet I got with the regulator said specifically to put it between the needle valve and carb with this type of engine. Yes I am using case pressure with the supplied new version check valve.
This may be a stupid question, but why would you need a needle valve at all, if this is totally a demand system?

Greg

David Bathe

I totally agree. I one puts it between the NV and the carb... it doesn't make sense in my book. But who am I?
As stated, one the last engine I used it performed better BEFORE the needle. But then....
Listen, there are lots of V2's flying without problems. Why the cline?

OldRookie

My Feedback: (13)

Tank location....Post #5.

Greg

MJD

My Feedback: (1)

I know the .46 FX layout, I own a couple. Without a needle valve, the engine has no idea how much fuel to "demand", that's what the NV is there for. The word demand simply implies the regulator supplies nothing until you draw upon it - then it supplies fuel at a very low regulated pressure, but the amount that is pulled through is a function of venturi suction and needle valve setting. Without a NV you have no control over the mixture - it directly controls the ratio of air to fuel.

Putting the regulator between the NV and the carb sounds fishy, regardless of the NV location. As suggested, the regulator should go as close as practical to the NV assembly, and as close as practical to the height of the carb. Essentially, the location of the regulator becomes the location of a reserve of fuel available at a small fraction of a psi, but doesn't siphon, and that doesn't run out until the main tank runs out. This means you should just be able to dial in the carb, but people have reported issues at the top end depending how much suction the carb actually develops versus the regulator demand level, and the result when things are not right is that the fuel draw at WOT suffers due to the effective "loss" of the amount of suction needed to open the diaphragm. Symptoms of this are the need to open the HSNV wayyy up relative to "normal", and the loading up problems that surface at mid- throttle openings as a result - when the carb is doing it's job supplying enough fuel at midrange settings but the HSNV is cranked open. As David suggested, the only fix is to get the idle as functional as possible, set the top end, and you get what you get in the midrange.

That's my understanding of the situation. BTW what fuel and plug?

MJD

OldRookie

My Feedback: (13)

I am using Morgan 15% and OS #8 plug, APC 11 X 5 that allows engine to run at 13,300. Sweet set up when running properly.
I can get the low end and high end to run well with the Cline, but the mid range is totally unacceptable. Can't even think about living with it. Maybe I'll put my YS 45 in it.

Greg

David Bathe

Yeah, I appreciate you have tank issues... but why as ther are millions of V2's functioning perfectly as is.

OldRookie

My Feedback: (13)

Here is a copy of the original instructions included with the Cline regulator in 2005.
Check the last sentance of the first paragraph that says to put the regulator between the needle valve and the carb.

Greg

MJD

My Feedback: (1)

I see it, I believe you. Something about putting a metering orifice ahead of the regulator just seems weird. Could be the .46 FX/carb setup might just not like the PFCS.

I run a .46FX with 11-5 on 15%, hard pulling combo indeed. It's on a float equipped H9 US40, lots of vertical and all the top speed it will ever need.

MJD

prgonzalez

One thing to remember is the cline regulator works based on differential pressure between the tank and carburator. A spring inside the regulator counteracts the pressure of the tank to keep the internal needle valve closed stopping fuel flow. Under operation, the suction through the carb will create negative pressure or vacuum. This pressure is amplified by the regulator's diaphragm resulting in a force greather than the force of the spring. As a result, regulator's valve opens up allowing fuel flow. The amount of fuel is proportional to the opening of the valve which is proportional to the force of the diaphragm which is proportional to the vacuum created by the suction in the carb. If I remember well, the regulator is calibrated to start opening at certain vacuum value in the carb.

Having said that, the only way to calibrate flow in the regulator is by lifting or lowering the tab of the level on top of the spring. This alters the vacuum value at which the regulator will start opening allowing flow and increasing or decreasing the effective opening of the regulator's valve thus the total amount of flow through the regulator.

At the end, there is a delicate balance to achieve and maintain between all forces. My conclusion's after trying the cline regulator was that it is not a plug and play device unless crankcase pressure in tank, carb suction, regulator's spring force, and lever calibration meet your particular conditions at a high degree. As David expressed, I believe there is more chance to achieve good results with large engines. Evidence can be found in the pattern forum by pilots using it with 1.60 engines.

David Bathe

But where is the tank located that make the Cline necessary?
On the CG or what?
As stated, one godzillion V2's... and no issues.

As stated above, it's a complex mixture of variables that make a happy Cline engine.
As it goes... The Moki 1.80 has them all... it just worked well.
On the pattern scene, most people chose the Perry instead of the Cline on the 1.60s
It works very well with that engine, it has issues but you can live and work around them.
Then again, a Perry on other engines can be a heap full of problems... unless you change to a Perry carb.

As it goes, I'm not happy with either!
My YS engines function superbly... after that every things shallow in comparision.
On other acrobats, I've had FAR more success mounting the tank in the normal place and just mixing in slight elevator trim changes as flight conditions.
After all, you're only talking a few clicks surprizingly.

MJD

My Feedback: (1)

I believe the .46FX, while a general use sport engine, runs a moderately large throat by comparison than some of the big engines timed for lower peak rpm. I think it is true in general that many larger glow engines are not running proportionally as large a carb throat area due to lower peak rpm, and therefore are pulling more vacuum at the carb due to higher intake velocity. If so it seems logical that the issue that bites some engines is the level of vacuum required to open the regulator - or more specifically the ratio between that vacuum requirement and the amount generated by the carb. I believe the difference is what is left as fuel draw. If so that easily explains why smaller engines running large carb throats for high rpm breathing are needing wider HSNV openings to flow enough fuel at the reduced vacuum level, and why they load up at midrange. Conversely, larger engines with high intake velocities see much less change in proportion and I would guess then that they are proportionally less buggered up - i.e. their regulator-equipped needle settings would differ less from the normal settings.

Does this make sense to anyone else?

MJD

OldRookie

My Feedback: (13)

David Bath....And again refer to post #5. The plane I am trying to get going isn't a V2, It is the Venus 40. The center line of the tank is at least 1" above the center line of the carb. The engine is inverted. The tank is located in the nose of the plane. The front of the tank is right at the firewall. There is no room to move the tank back to the center of gravity. The clearance of the wing to the internal structure doesn't allow room for the tank at CG.

Greg

OldRookie

My Feedback: (13)

prgonzalez....My next and last step in trying to get the Cline to work with this engine would be to start adjusting the tab that controls the spring tension as you mentioned. I think I'll start by bending it down so it is about 1/64" below where it should be and see if there is a difference in mid range, once I readjust the high and low needle valves to work at this setting. I am also going to put the Cline back between the needle valve and the carb, as this seemed to be the best compromise.

Greg

prgonzalez

Absolutely!

prgonzalez

Greg,

The regulator instructions tells you which direction of the tab will provide more or less fuel. Take it as a learning experience. Take notes of what you do and your results. I remember going through each one of the step you are just describing.

I learned a lot using the regulator but I lost my notes[&o]. At least I hope they are missplaced.