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Non-pumped 2-stroke with tank at CG?

Old 05-13-2009, 06:24 PM
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Jetdesign
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Default Non-pumped 2-stroke with tank at CG?

Just wondering if anyone has experience running something similar to an OS 120AX without a pump and with the tank at the CG. The tank is 12 inches from the engine back plate and it was suggested I try running the setup without a pump (not thrilled with performance of the VP-30). I figured it would be a good idea to post it before I tried it.

Thanks.
Old 05-13-2009, 07:04 PM
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Rcpilot
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Default RE: Non-pumped 2-stroke with tank at CG?

It won't work. Been there, done that.

If you don't like the perry junk, you should get a Cline regulator. Easy install, easy tuning, reliable.
Old 05-13-2009, 07:56 PM
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BillS
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Default RE: Non-pumped 2-stroke with tank at CG?

I believe there is little flight performance to be gained by moving the tank to the CG. However there are a lot of troubles to be found with the tank far from the firewall. A few calculations of CG change on a 120-size airplane might be important in your evaluation.

Bill
Old 05-13-2009, 08:02 PM
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w8ye
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Default RE: Non-pumped 2-stroke with tank at CG?

The 120AX seems to be rather sensitive to needle setting and tank position as it is. It'll never work with the tank on the CG

A Perry pump may work but most likely it will take a Cline
Old 05-13-2009, 08:54 PM
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Jetdesign
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Default RE: Non-pumped 2-stroke with tank at CG?

Is cline really that much better?
Old 05-14-2009, 07:04 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

I have never tried the Cline, but have never had problems with their pump. I suppose some have trouble tuning it, or Conley has quality control issues that were not there before they took over Perry products. Though at least one pump I used was made by Conley.
Old 05-14-2009, 10:13 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

ORIGINAL: gaRCfield
Is cline really that much better?

YES! YES! YES! The Cline is a miracle!!

The perry is a pump. It pumps fuel. You have to adjust it to work properly and that seams to be the trouble with the perry unit. You have to get it properly adjusted to pump enough fuel at wide open. But then thats too much pumping for idle and mid range. So you have to install a T and a bypass line back to the tank. But then the T sucks air when the tank level goes down so you have to .......... blah blah blah blah ......... [:'(] [:@] [:'(] [:@] [:'(] [:@] [:'(] [:@] [:'(] [:@] [:'(]

The Cline is very simple and very effective. You tap the backplate and install a one-way check valve. The check valve is installed as close to the engine as possible. This pressure line is plumbed into the tank where you would normally run your muffler pressure. Muffler pressure is no longer needed, so plug the nipple on the muffler.

Now you have a pressurized fuel tank.

The pressurized fuel is pushed up to the Cline regulator. Mount the Cline as close to the carb as possible. No more than 1" away. Let it dangle in the wind. Do not hard mount it.

Now you have pressurized fuel pushing on the Cline and waiting to go into the carb. The Cline works on the vacuum from the carb venturi. It only opens enough to pass fuel based on how much vacuum is senses from the carb. Higher RPM = more vacuum. More vacuum = more fuel.

There is no adjustment on a Cline. You don't adjust it. Don't need to adjust it. No fiddling around. No bypass lines. No BS.

You simply install the Cline and then tune your engine for best performance. Don't tune rich as you would with a normal 2-stroke. Just tune it to peak RPM ands then back up rich maybe 2 clicks. No more. The Cline is SO PRECISE that if you tune 4 or 5 clicks rich it will not work right. The engine will run rich, just like you tuned it.

Install it. Tune your motor. Fly. So simple and so trouble free. Just fly fly fly fly fly fly fly and don't worry about your engine ever again.
Old 05-14-2009, 11:57 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

But then thats too much pumping for idle and mid range.
It has a pressure regulator, so that it will not pump as much at midrange and idle, however if too much pressure it will be too rich at midrange. You can adjust the pump down to about the same pressure as muffler pressure. That is if it works correctly, as I stated I suspect Conley has quality control issues.
Old 05-14-2009, 12:47 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

I did the Cline with an OS 91 FX and never got it to run right. I know some do and then some don't. Why gamble? Break down and buy the appropriately sized YS engine(only four-strokes available now) and it doesn't care where your tank is. Down the road when you have stored in your unused parts bin the _______(fill in Perry or Cline as appropriate) pump and the 120 AX you will wonder why you tried to solve a problem you could have eliminated with a YS engine. If you still want a Cline regulator, I'm sure I could make you a good deal on the one in my "unused parts bin."
Old 05-14-2009, 01:01 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

I did the Cline with an OS 91 FX and never got it to run right.
The Cline supplies fuel just below atmospheric pressure. If the carb is oversized or has a tendency toward lean midrange then I suppose the Perry pump may be a better choice.

Why spend the extra money on a YS and not have the fun of figuring this out?
Old 05-14-2009, 01:21 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

ORIGINAL: Sport_Pilot

But then thats too much pumping for idle and mid range.
It has a pressure regulator, so that it will not pump as much at midrange and idle, however if too much pressure it will be too rich at midrange. You can adjust the pump down to about the same pressure as muffler pressure. That is if it works correctly, as I stated I suspect Conley has quality control issues.
I've been there. Done that. You're acting as if I didn't know how to adjust the stupid thing. Trust me, I've tried it a few dozen different ways on several (not just 2 or 3) engines. Never got one to work right. Tried plumbing tricks. Tried stiffer springs. Tried weaker springs. Tried check valves. Tried bypass T's. Tried glow plugs. Tried larger fuel tubing. Tried smaller fuel tubing. Tried this fuel. Tried THAT fuel. Tried several new tanks. Tried new O-rings in the carb. Tried all kinds of stupid stuff. Even tried turning the little thumb screw on top to "adjust the pressure"

I'm not an idiot. I like 2-strokes. As a matter of fact, thats ALL I fly. I don't own any 4-strokes. Don't like 4-strokes for my flying style. I've been working on 2-strokes since I was a 10yr old kid and I'm 37 now. I know EXACTLY how a 2-stroke works and I know how a carb works. I even know how to adjust a carb.

I'll be darned if I can make a Perry pump work correctly. Call me stupid, I guess.

Get the Cine and hook it up according to the directions. Go fly. It's worked on a half dozen motors for me so far. Never had a lick of trouble out of any Cline. I just install it, fuel the plane, flip it and smile.
Old 05-14-2009, 08:02 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

Speaking of clines.

Do you do anything to seal or secure the little plastic elbows on the cline?

I have a new cline here that i want to use on a Webra 1.45R and the elbows don't seem to be tight enough to stay on the reg. I'm worried they will fall off in flight.
Old 05-14-2009, 08:27 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

On some engines and some set-ups the Perry will work. It spite of the name there is no regulator in the Perry except a over all pressure limiting device

But the Cline regulator is a sure thing. This is a genuine BZR type regulator. It lets no fuel through unless there is a demand for it by the engine. Actually the mechanism in it is just the regulator from a Walbro WA or WT type gasoline carb.
Old 05-14-2009, 09:45 PM
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Default RE: Non-pumped 2-stroke with tank at CG?


ORIGINAL: CustomPC

Speaking of clines.

Do you do anything to seal or secure the little plastic elbows on the cline?

I have a new cline here that i want to use on a Webra 1.45R and the elbows don't seem to be tight enough to stay on the reg. I'm worried they will fall off in flight.

Fit the plastic elbow in the hole just a bit. Put a drop of medium CA on it. Spin it around 1 full turn as you push it down in the hole until it seats. It'll never come out. Work fast.
Old 05-14-2009, 10:04 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

Thanks.

I thought about CA but was unsure if it would damage the plastic.

I'll give it a go.
Old 05-14-2009, 10:24 PM
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Jetdesign
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Default RE: Non-pumped 2-stroke with tank at CG?

Thanks a lot guys. Sounds like the Cline system is similar to the regulator in a YS although I could be really wrong about that.

I will play with the Perry for one more weekend, then give the Cline a shot.

I can't believe I am now really considering ditching the DS821's and 120AX for some high end servos and another YS (140); it's only been one year.

Does this ever end?
Old 05-14-2009, 10:32 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

Joe,

If the OS 120 is for Venus II, then YS110 will work just fine.
Old 05-14-2009, 10:56 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

The Y-S and Cline work differently

The old Y-S regulator is a engine speed regulated dosing device

The Cline is a demand regulator

Old 05-14-2009, 11:57 PM
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Default RE: Non-pumped 2-stroke with tank at CG?

Hi Joe,
Have You thought about using a heater tank?







Hoss Allen
Old 05-15-2009, 12:33 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

Header Tank?
Old 05-15-2009, 02:41 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

Perry could steal the show if they would incorporate a demand regulator with their pump.
Old 05-15-2009, 04:15 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

Hummm, so maybe the solution for all those Perry's and Clines we have laying around is ti use the perry to deliver the fuel from the tank to the cline and the cline to regulate the fuel to the Carb? I'll try it next week.

Just so I've tird everything, what is the concensus when using a cline and remote needle valve. Tank, cline, needle, carb? Or Tank, needle, cline, carb?
Old 05-15-2009, 05:47 AM
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Default RE: Non-pumped 2-stroke with tank at CG?

I would try Hopper (Header) tank for delivey & the Cline
Old 05-15-2009, 06:28 AM
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Default RE: Non-pumped 2-stroke with tank at CG?


ORIGINAL: Sport_Pilot

I have never tried the Cline, but have never had problems with their pump. I suppose some have trouble tuning it, or Conley has quality control issues that were not there before they took over Perry products. Though at least one pump I used was made by Conley.

Just my $.02.

What little problems the Perry has in regulation seems most noticable on smaller engines, such as .40 to .50 sizes. Once at 1.20 or above sizes, the Perry design seems to work just fine, especially if one follows the latest data available from the manufacturer's website.

However, with all of that said, I prefer the Cline Regulator above all available third party systems.

Frankly, I don't think there is sufficient advantage to be gained by placing the fuel tank at the model's balance point. I prefer to run the tank in the traditional position immediately behind the firewall.


Ed Cregger
Old 05-15-2009, 09:18 AM
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Jetdesign
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Default RE: Non-pumped 2-stroke with tank at CG?

I flew my plane both ways - tank at CG and tank at firewall. Personally I think the plane flies much nicer with the tank at the CG; enough so that it's worth trying to figure this thing out. I'm sure some of it depends on the plane. I don't even think I will fly my Venus 40 again until I can figure a way to get the tank back to the CG.

Header is not a bad idea but I've already gone through a lot of work to move the engine back on the mount and recut the cowl to shift the CG back. The plane is nose-heavy enough, and there isn't much room left to work with behind the firewall.

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