n19htmare

My Feedback: (1)

I'm not sure what I'm doing wrong but there are a few things I can't figure out on my 4 stroke saita 82. It is about a month old with a gallon or so through it.

My throttle is connected properly by which I mean that the carb opens up gradually while move up the throttle stick... I tuned it on the ground and all but the weird thing is that when I'm flying it, I can't tell the difference and feel no different between half throttle and full throttle. It seems as if the engine is going max RPMs at half throttle and anything after that, I feel nothing.

What am I doing wrong in my tuning?


Also one more thing on my Idle and i dunno if this has anything to do with the above problem. My plane is a 46 size Phoenix Yak 54, I have the 13x7 APC prop on the 82 and if I idle to where the engine is running wee, the plane wants to taxi and does not hold. If I trim the idle down to where plane does not want to taxi, the engine seems to have a hard time idling, shaking the plane like putt putt putt putt.

Help please .

alan0899

G'day Mate,
It needs more prop, a 13x7 is not enough load, it is a 4 stroke, & must be run like a 4 stroke, I would try 14X8 APC, & retune.
http://saito-engines.info/prop_sizes.html

chashint

If you have not leaned the low speed needle you need to do that after you switch props and retune the high speed needle.

n19htmare

My Feedback: (1)

I tried a 14x6 MA prop, same thing.
I leaned out the LSN almost 1 full turn..... Still plenty of smoke and doesn't bog down the engine when I go WOT.... so lean out the LSN more?

ChuckW

The first thing I would do is get a few tanks of fuel through it to break it in. Then gradually start leaning the needles. I was surprised just how rich the low end was set on my .82 from the factory.

As for the plane wanting to roll away at idle, that seems to be a common thing. The big props make a lot of thrust and even at lower RPM, the plane can want to move. Once the engine is broken in though and the needles adjusted right you should be able to achieve a much lower, reliable idle which will eliminate or at least make the problem much better.

Just be patient with the engine. It can be a little frustrating when new but you'll be rewarded with a reliable, sweet runner in the end.

alfredbmor

Yes more running time is the answer. Do not try a 14 x 8 prop, it is to much prop for this engine, mine handles fine the 13 x 7; 13 x 8 and the 14 x 6. I found that the K series Master Airscrew works fine and because of the lower pitch tends to move the plane less than others at idle. Remember to set the HSNV first then the LSNV and finally adjust again the HSNV.

The Ghost

Go [link=http://saito-engines.info/throttle_setup.html]HERE[/link] for info on seting them up. You WILL need a TACHO, you don't say if you use one or not.

Cheers

n19htmare

My Feedback: (1)

Thanks everyone.. I figured a gallon would be enough to break it in I guess not yet... I hope I didn't damage anything by running the engine (never lean or over 10K RPM) before i got a couple of gallons through it.

The Ghost: Yes I use a tack to find the max RPM (which is around 9.9 to 10K) and then I richen it back about 400-500rpm. Thanks for the link.. can't wait to try it out . I get the feeling I'm running very rich on my LSN.

ChuckW

Guess I read right over that part. If you've put a gallon of fuel throught, keep leaning the low end 1/8-1/4 tun at a time until it is dialed in. If you go too far, just back it out. Once it is close, you should be able to get it idling slower.

2slow2matter

My Feedback: (1)

14X8 is the prop for the saito 1.00, NOT the .82. A 13X7 is probably right, or 12X8 if you want more pitch. Lean the low end, that is the key to the saito's. they come sloppy rich on the low side, and that has helped keep your engine well lubricated during break-in. Now, after a gallon of fuel, it's broken in good enough to start leaning out. This will make it purr like a kitten while idling down around 2000, or even a little less. This will also change the high speed tuning just a bit, which might give you the RPM range you are looking for.
Are you using at least 15% nitro? Saitos like nitro. They will run fine on low nitro, but the higher the bettermore consistent, low speed idle as well as more power on the top end, but you will have to open up the needles a bit, and you will burn more fuel.

dignlivn

FWIW,

I,m running a 13x6 or 13x8 on my 82.
It has just over a gallon thru it and it
will idle without moving my 40 U stick.
Our club has Bermuda grass RW btw.

I'm still running on the Rich side and
have not changed the LSNV as of yet.
What is the weight of your AC ?

Bob

n19htmare

My Feedback: (1)

Thanks for you help fellas, got the engine running well. I had to lean out the LSN A LOT following the instructions on saitos site. It now sits around 2200-2300 rpm idle and doesn't vibrate as much and my plane does take off like it used to. Top end rpms top at over 10K, pass the limit of the engine so I have it richened out to about 9600rpm with a 13x7 prop which is plenty for this plane and unlimited vertical. I got some 14x6 APC inroute so i'll give that a shot too .

2slow2matter: Yes I'm running 15% nitro, it just tunning issues.

Dignlivin: no grass field here, it's paved and with how light the plane is, even at 2200 rpm it has a tough time staying absolutely still. But it does help on the landings

rlipsett

the one thing that nobody has mentioned is that engines do not respond linearly to throttle position of the barrel. there major rpm pickup is in the low end and the rate of rpm increase decreases the more the thottle is opened until you reach wot. with my setup I usually program a throttle curve into the engine so that it simulates linear engine response. and yes my engine hits its maximum rpms at the top and idles good at the bottom

forestroke

also, consider that the 13 x 7 is a torque prop and thus your performance should be fine. you shouldn't be doing any speed runs anyway! what i've noticed is that as the engine unloads too much at speed on that prop so when you're going fast the loading on the engine between 70% and 100% is minimal. but if you're pulling out of a hover, 70% and 100% will make a big difference and that's why when you're on the ground you can hear the difference because it's static.

now if you use a 10 x 10, you'll probably hear the difference, particularly when the airframe disentegrates :-)

good luck!

Gray Beard

My Feedback: (-1)

Not going to get into tuning an engine but I will tell you how to keep your plane from rolling around. You have to tighten up the wheels!!! I use A washer between my wheel and wheel collar, between the washer and collar I use A small piece of fuel line. Add pressure onto the fuel line with the wheel collar and your wheel won't be so free wheeling that you have to chase your plane around in the pit area. Trust me, it works!!

opjose

No kidding!

The Saito's seem to have a very WIDE tolerance for improper tuning.

They'll keep idling with the LS needle extremely rich.... as it comes from the factory.

After a gallon of fuel I started turning the LS needle in and I was amazed at how far I turned it ( 2.5+ turns IN ) before I hit the idle sweet spot.