Hobbsy

My Feedback: (102)

When I bought the RCM it had the engine compartment fuel proofed but I had also given it a coat of thin CA, so there was no damage. It's one of my favorite planes to fly.

N429EM

Jim,
How did you configure the 3-line setup?
I always thought the third line was just to make it easier to fill the tank?
If this is your case, did you plug the 'new' third line?

EJ

Bladejunkie

N429EM,

the way it was setup,was one line with clunk goes to carb,another line with clunk goes to the pressure tap on the muffler this line also has a one way check valve in it,and the third line is the old vent line,which is plugged off when not fueling.I hope I explained good enough for you.If you happen to read Fly RC magazine this setup is in the June issue"Uniflow Secrets Revealed" on page 32.

Thanks for your responce

Jim. Saito Club Member#509

freeonthree

My Feedback: (1)

The pressure hose should go to the vent, not to a clunk in the fuel.
Only the line to the carb should go to a clunk.

johnS555

My Feedback: (27)

Bladejunky, I like to put a clunk on the 3rd fill line so it can be defueled thru it as well as fueled.... John...# 118 or 119 Saito, I forgot....

freeonthree

My Feedback: (1)

Sometimes I use a second clunk line to a fuel dot, but their so darn hard to pull out, so I usually just make two holes in the cowling, put in rubber gromets, and loop the fuel line thru the holes, then splice with a filter. Pull the clunk line off the filter and fuel or drain. My scale picky friend Greg hates it when I do that, but I perfer it that way for me. lol

rlmcnii

My Feedback: (3)

Bladejunkie,

I have read about the uniflow system. The benefits of it are not entirely clear to me and the article to which you refer did little to make those benefits any more clear. However, many people swear by the benefits of the uniflow system.

Are you certain there is supposed to be a check valve in the pressure line?? The fuel pouring out of the carburetor may result from too much pressure in the tank. The fuel regulators, Cline and Iron Bay, depend upon high pressure in the tank. Those regulators, however, control, i.e. regulate, the flow of fuel to the carburetor. With the uniflow system there is no regulator between the highly-pressurized tank and the carburetor.

Perhaps removal of the check valve would help.

Let us know what happens.

freeonthree

My Feedback: (1)

Without a check valve in a pressure hose going to a clunk, the fuel would just run out. Personally, I think that the pressure from the weight of the fuel would overpower the slight pressure of the exhaust from the nipple, and fuel pressure would be null. Seems that way to me...

horseman

Hey thanks,but I know you have to start it backwards for it to run forward, it still runs backwards,so logic would tell you to go the other direction ,but no success, so what is wrong now?[]

Ernie Misner

The blissful, KISSful, system does use 2 clunks, one to the carb and one to a fuel dot. (simpler and lighter though is just to drill a tubing size hole in the cowl, pull the fill line through the hole, and instert the plug only from the fuel dot, discarding the rest of it, then push the excess tubing back inside of the cowl) Of course the muffler pressure goes to a vent line in the top of the tank as normal.

No, the two clunk lines do not get tangled inside of the tank. Using regular silicone tubing on each clunk line keeps them just stiff enough.

Ernie

freeonthree

My Feedback: (1)

Maybe the cam timing is off one or two teeth.

freeonthree

My Feedback: (1)

I have a fuel dot on one plane. I think i'll try it without the locking o ring. Either that, or I gotta stop bitin my nails. lol

hy flyr

My Feedback: (27)

I'll join the club!
I have the .56 on a small stearman, .72 on my contender, a 100 on the Hangar 9 Mustang, a 100 on a Hangar 9 P-40, and a 150 on my PT-19. They are all mounted inverted except the .72 and it's always been a little touchy. I've got the Keleo exhaust for my 100's and they run and sound great.

Ernie Misner

>>> I've got the Keleo exhaust for my 100's >>>

I thought that exhaust was for the radial engines. What does your look like, have a link to that exhaust?

Thanks,

Ernie

Ernie Misner

freeonthree, the clunk/fill/unfill line is plugged when not filling or unfilling.

horseman, the engine has to have just the right amount of prime to start with a backflip. It can be very hit and miss at times. It can be so much easier and safer just to use the electric starter. I do start my little .46 2-stroke with a backflip sometimes just for the fun of it.

Ernie

Bladejunkie

Hey guys

getting back to the uni-flow system,I tried the same system on my other LT-40 that has a FA-56 for power and I got it to work,but only after nearly closing both needles all the way!!!I'm afraid I'm going to blow the fuel tank though,because of the pressure this thing builds.I've decided to put everything back to normal and call it good.My 56 runs better with no muffler pressure at all,as a matter of fact all three of my Saito's run better with no pressure.K.I.S.S.still rules!!!

Jim. #509

freeonthree

My Feedback: (1)

I know that, I have a fuel dot on my Decathlon.

jusplanecrazy

Hi Guys,
Need some help from the Saito "Think tank"....Got a Saito 80 on my GP Reactor.Motor is inverted...Having a problem with surging in the air,and flooding out at idle...Thought it might be a motor problem ,so I took a Saito 80 that purrs off another plane,and put it on the Reactor .Same result. Now the carb is pretty low in relation to the tank,about even with the bottom quarter of the tank...Using a 3 line 2 clunk system.One clunk line to the carb,one clunk line for fuel/defuel,and the vent to muffler.....Problem!!! Can,t move the motor up.That would take it off the thrust line .Can,t move the tank down,no room....I,m thinking that my only option is to move the tank back to the C/G,and add a pump.I,m dumber then a rock about pumps ,so I don,t know if this will solve the problem.......I know guys are using Saito 82s on this bird,and haven,t heard of any problems from them...Is the 82 that much differant then the 80 ? I,m guessing motor ,and carb position would be about the same for both........HELP !!!.......Thanks Guys...Bill

Hobbsy

My Feedback: (102)

JPC, I ran my Saito .80 inverted on my test stand by simply flipping the PSP over, I also flipped the tank in the tank holder, the LS needle is about 1/4 turn leaner than upright. I didn't take the picture upside down, honest.

N429EM

Jim,
I know how the 3-line setup is supposed to work. My first plane is/was a NexSTAR. I was trying to help decipher your problem.
So, in reading your setup, if the pressure line has a clunk, could it be you're blowing bubbles into the fuel, and causing foaming problems?

Just tryin' to help,
EJ

N429EM

After reading more of Bill Robison's wonderful document, I decided to reset the valve adjustment on my FA-80 to .0005".
When I had finished, I was turning the prop hub (by hand), and I heard what I thought was an air leak. As I investigated, I found that as I turned the hub backwards toward the intake openning, there was a rush of air coming out of the carb. I didn't have time last night to run the engine, but I am curious. Have I improved the valve timing, that much, that when the engine is run forwards it's going to breath better? Or, have I gone the exact opposite, and screwed up something?

EJ

donkey doctor

Hello Jim; If you have the valves set at .004, the cam has to turn a little bit more to raise the valve off the seat then it would have to turn if it was set at .0015. Therefore opening duration is increased. If both valves are set at .0015, overlap increases, since duration increases. The goal is to get the maximum amount of mixture in and out. Too much overlap is what causes fuel to be blown out the intake, when the intake is opened too early in the exhaust stroke. A velocity stack on the intake is used to contain that excess fuel blown out, and make it available for the engine on intake. It is a bit of a balancing act to find the perfect duration so that fuel isn't wasted. So the solution isn't as simple as just reducing valve lash.

Ernie Misner

EJ, don't turn the engine backwards. In doing that, it will be blowing out through the carb, like it blows out through the exhaust when turning forewards.

Ernie

19ghost66

please for information: I have changed in my saito 150 bearings, but hour I have fear not to resume in correct timing valves you can help me sending me of the photos? thanks
[email protected]
tank you

RC Specialties

N429EM,

Here is some food for thought!

“As the engine warms to operating temperature the various chunks of steel and alloy inside the engine grow slightly due to thermal expansion. Obviously as the valve train components are brought up to running temperature they expand along with all of the other bits and pieces. If there is insufficient lash between the valve stem and its actuating mechanisms when the engine is cold, there will be even less clearance when the engine is hot.
If lash is reduced beyond a reasonable amount, several things occur, all of them unpleasant. First, the valve timing is changed slightly, and this may affect performance, and emission outputs. But there is an added complication: The exhaust valve stays alive because it's able to transfer a fair portion of the heat it absorbs from the combustion process directly into the cylinder head when it's resting on its seat. As clearance is reduced, the valves spend less time on their seats. This means the exhaust valve(s) has less time to give up its heat, leading to anything from detonation, pre-ignition and engine overheating, to a warped or burnt valve.�