I have an OS .32SX mounted and the fuel tank is 10" away. I fly 3-D and was wondering if the oscilating pump will work fine. With all the aerobatic gyrations capable nowadays, will this affect the operation of the pump? I have never needed a pump before so this is new for me. Thank you.
Adam

The only way to really know is to try it.
The oscillations will actually help the pumping action

The oscillating pump was intended for four strokes

The instruction manual states that it is perfect for 2 cycle.
Unless someone chimes in with a negative I will try this route.Thanks
Adam

Um, I'm not sure of that. My first use of the Perry micro-oscillating pump was on a ST .60 around 1980. At the time, OS had the only 4-strokes available, a .61 and the Gemini twin, AIR. The pump was mounted on a plate that was in turn mounted to the backplate of the subject engine. The Gemini was so smooth that I'm not sure the pump would have worked on it. Also, it had cast-on mounts on the backplate. Not sure if the Perry could have been mounted there. The .61 had the cam in the back, so there wasn't much room for the mounting plate back there. Anyway, who would market a pump for a engine type that wasn't much in use at the time?

CR

I've used it with great success on 2-strokes but I'm not sure of its capacity to lift fuel that far. On balance, I've never had a PMO engine lean out on an upline. More G's there than 10" in a hover?

I'm sure you know that the PMO uses Newton's law that for every action, there's an equal and opposite reaction. IOW, there's a piston in the pump that slides back-and-forth in reaction to the engines vibration on the mount. There's got to be an upper RPM limit on the piston due to inertia, eh? How fast are you turning that .32?

Anyhoo, as W8 said there's only one way to find out but I'd hover the model 2 mistakes (G) high at first!

Let us know how it works out, please.

CR

Help!

I just installed a Perry regulator pump in my extra. It's flying with a Tower hobbies .75 2 cycle. How do you adjust the thing? The instructions that came with the pump say nothing about it!

Instructions for adjusting Perry pump:

1-Remove fuel line from back of pump.
2-Remove fuel line from front of pump.
3-Insert pump into round file (trash can).
4-Install Cline regulator or Iron Bay regulator-- no adjustments necessary
5-Tune engine.
6-Fly with a smile.

Step 5 and 6 might not happen in all cases. I had dismal luck using the Cline with an OS 91 FX with fuel tank about 10 inches aft of engine. The engine was infinitely more difficult to tune(or close to a tune) and had a very narrow needle range. I finally used a YS61 pumped two-stroke which is working flawlessly. Just remember that the pressure of the fuel to the carb is different with a muffler pressurized fuel system and the Cline. The Cine regulator works like a SCUBA system. It supplies fuel to the carb on demand(suction). The carb was designed to operate and draw fuel from a system that has some positive pressure(fuel tank pressurized from muffler). There is a difference. Obviously some engines work fine with it. But don't assume it will be compatible with all engines.

It's worked perfectly on about 6 engines for me. No, that doesn't mean it will work perfect on every engine, but it's a whole lot more reliable than any Perry pump or fuel regulator that I ever tried. I pulled my hair out with several Perry pumps on several different engines. Never could get one to work the way I wanted. I know others have reported success. I just never found them worth the trouble.

When running a Cline regulator, I have always ended up running my needles out about 1 turn richer than where it was tuned before I installed the regulator. It is a vacuum demand regulator, and there really isn't a whole lot of vacuum going to the regulator. So, you need to open your needles a little bit more to make it flow the right amount of fuel. The guy (Bill) from Cline told me this back when I bought my first one. I have always had great luck by simply ignoring where my brain THINKS the needles should be and just tune them to make the engine run good. No assumptions. Just tune it.

YMMV

Rcpilet, a question for my knowledge. You know the instructions say to have the regulator within an inch, as I recall, of the carb. That means on engines like the OS 91 FX that the regulator is between the needle valve and and the carb. Did any of your engines set up this way? I've heard good things about the Cline. Maybe I'll find a future use for it. By the way, if you've talked with Bill lately you know he is trying to sell the regulator(proportional fuel control system, more properly) business. Someone may have already picked it up by now. It was last summer that I talked with him a couple of times.

I believe the Cline should be installed BEFORE the needle. And I believe the needle should be located in the side of the carb. I despise remote needles. I always hooked mine up with the needle in the carb and the Cline as close as possible. I know some guys (Hobbsy ?) have installed the Cline between the needle and the carb and had success.

I am kind of stuck in my ways. I know that I always had good luck with my Cline plugged in right at the carb, and I always run engines with the needle on the carb. Never tried a remote needle and a Cline together. If it ain't broke...................

I know the Cline is for sale. I wish I had the money. It's a great product. Maybe he is getting on in the years and wants to go fishin' now?

Ironbay has been "revamping" their website for a couple months. Wish they'd hurry up.

If the adjustment screw came out of my VP30, is it necessarily now ruined? Or can I put it back in and re-tune?

Thanks.

I have been using a Perry VP30 regulating pump with a OS91FX with a tune pipe in a pattern plain for more than a year. The pump is in line from the tank which is on the CG. I had no problems adjusting it and only had to decrease its pump action by turning the hex screw out about 1 ½ turn. With 10% nitro the main needle it about 1 ½ turns open. Mixture is very constant and the oil that comes out the tune pipe is completely clear, my Plugs are lasting much longer.

There's a spring in there and if it falls to the side you need to reset it to where the screw goes down through the spring

The Cline or the IronBay regulator need to read the demand at the sprabar, the HS needle only effects the max flow so it doesn't matter where it is. The LS needle controls the intermediate flow, the regulator responds to the demand as the LS needle permits hence the name PCFS or Proportional Control Fuel System.

Thanks W8YE.

I just got the idea to try small diameter fuel tubing from the pump to the carb (OS 120AX):

My engineering school brain says it won't make much of a difference; the pump is working at a given rate based on engine speed and therefore provides a flow rate independent of tube size. The smaller diameter tube will mean that a smaller volume of fuel will go through the tube, but will flow at a higher velocity providing an equal volumetric flow rate compared with the larger tube. Unfortunately I don't know enough about how fuel is drawn through the carb and thus how it would respond to different loading conditions.

The other part of my brain says too much fuel to begin with, smaller fuel tube has got to change something.

It's pretty late and I feel like I'm missing something (like what might happen at WOT?) so any thoughts would be great. As of now the screw on the pump is out far enough that I'm worried about it falling out and my low speed needle is either fully closed or darn close to it. Performance is OK idle, decent transition, and decent top end. Not much room left for adjustment but I believe I should be able to achieve very good idle, transition, and top end.

You may as well try it

In re using smaller diameter tubing affecting fuel flow: Yes, it will. In Fluid Dynamics, there is a function called CV. Basically stated, given a constant pressure or vacuum, total flow volume thru a smaller diameter tube will be less than with a larger diameter due to friction loss.

Now, in terms of setting up a Perry pump; an (unfortunately ex) old timer who loved these things gave me a procedure that I haven't had any problem with with gas or nitro models. Its somewhat of a pain since it is a two person and a tach (or a good ear) procedure. First, with plane at horizontal, get your motor at WOT and maximum rpm (do pinch test to determine best needle position), tach it. Now, hold plane in a vertical position and tach it again. If no change (OK). If an RPM drop (too lean, not enough pressure), turn the screw in. If your a violent 3D flyer, turn the screw in a bit further to compensate for G forces to increase pressure (200-300 RPM drop at WOT vertical due to richness).

Conversely, you can determine if your pump is giving is giving too much pressure by doing this test, backing the screw out each time until you get the too lean RPM drop and backing off your last adjustments.

I got a call from Gary at Connely (sp?) who sells the Perry pumps. He advised to use a 'T' fitting as close to the carb as possible, and run a third line as a return line. He said all my problems would be solved[8D] Makes sense, and this is even how our diesel test engine at school is setup, with a fuel pump and a return line from the fuel injectors.

I am probably going to try the narrower fuel line first, and maybe even on the pressure line. Easier fix than pulling the tank, but truthfully I don't think the thinner lines will do much.

Today I tried everything, and got the pump working pretty flawlessly.

The narrower fuel line did nothing.

I set up a 'T' very close to the carb as I was told by Connely. I first tried it with a one-way valve in the line and this was not much of a help. There is no pressure running through the extra line, just fuel. I believe the fuel got to the valve and stopped.

Last I tried with regular fuel line from the 'T' to the tank, and found satisfaction. Very, very good transition, easy tunability, and much better fuel consumption. I tried this setup first with the extra line feeding into an external tank, and A LOT of extra fuel was coming out. The Perry pump really works harder than it needs to. All that extra fuel that was bogging down the transition was getting shoved out of the muffler, unburnt. With the extra line, all that extra fuel just goes back to the tank, and I got a few extra minutes of run time.

I found this online. Shows how using a T to relieves the pressure to the carb.

Not really sure what happened: pump seemed to be working well but I was really nose heavy. I moved the engine back on the mount and had to relocate the pump, and 5 subsequent flights resulted in 4 dead sticks and a ripped out undercarriage.

I tried re-routing the return line from directly into the tank stopper to a 'T' just before the pump, as in the diagram. I seemed to be having air issues, could not get the engine very rich at WOT, and again had a boggy transition.

Removed the 'T' system and tried leaning out the mixture valve. Now idle mix is very lean, high end is pretty leaned out, and although transition is good the engine loads up with excess fuel if you have the stick anywhere in the middle of the throttle range (aka flying the plane). However no dead sticks.

So, my questions now are:

What does the drain hole on the pump do, and what is the result if the pump is unable to drain (i.e. hole not facing down)?

Does a Cline system really work better, and does anyone here actually have experience with the Cline on a larger (120) size engine?

Thanks. Sorry to keep dragging this one on, but this intermittent operation business is driving me nuts and I just want to fly my plane with the tank on the CG (without having to buy another YS this season). Don't really think I'm asking too much...

This is indicitive or too much pump pressure, adjust the pressure down till mid range is not so rich. You will have to richen up the high and low needles after adjusting.

I have the screw on the pump out as far as I can without it being in danger of falling out. Adjusting the screw on the pump doesn't seem to change anything.