Capt Lou

PM:

Regarding your break-in, the Saito manual recommends that you run the engine for 40 minutes for the break-in cycle, with the first 10 minutes at no more than 4000 RPMS. With two tanks on the engine, you passed the 10 minute mark but I doubt you have reached 40 minutes. The break-in period is critical so complete the total 40 minutes. Also, especially during the break-in, run the engine rich until you use a tech and have it set accordingly. It is better trun these engines on the rich rather than lean setting. I agree with you that Powermaster 20/20 is a good fuel for these engines. This is the only fuel I use and have not had an issue with these engines. Good luck with it.

Capt Lou

Hobbsy

My Feedback: (102)

I had an opportunity to wring out a new TurboHeader for the Saito 2.20 under developement by RCSpecialties. The results are very good.

Engine===Saito 2.20 plain
Fuel used==WildCat 15% 2/4 with 18% synthetic lube
Glow plug==OS-f
Props tested==MA 20x6 Classic and Mejzlick 18x8
RPM with stock exhaust
Master Airscrew 20X6 rpm==7,600
Mejzlick 18x8 rpm=======8,250

RPM with TurboHeader
MA 20x6 rpm==========7,650
Mejzlick 18x8 rpm=======8,500, this is a solid 250 rpm increase that holds indefinitely and is repeatable.

chashint

OK fellows here is an update on the events of the morning.
First thing to note is the 8k reading at WOT last night was bogus.
In the good light it was 5700.
Ran the first tank this morning using all throttle setting leaning the HSN till I got 8k then I had to kill the engine and tighten the muffler.
Finished off the tank varying the throttle in 'timed' increments.
Let it cool so it was warm to the touch and fired it back up.
Once at WOT I took the HSN to 9k, I stopped there since I do not want to risk a lean run.
Backed it down to 8.3k and played with the throttle.
Noticed that after idling for a short period and going to WOT the rpm would peak at 9.2k and then settle to 8.3k, this was repeatable.
The engine did not seem to be in duress at the high rpm, a consistent smoke trail was always present.
I have never let a tank of fuel run dry; I have used the throttle to kill the engine.
When I restarted the engine my tach blew off the stand and hit the concrete, danged thing quit working.
Shut down the engine and took apart the tach didn't see anything obviously wrong with it, but I cleaned it and touched the guts.
Of course it reads a light bulb just fine but it no longer picks up the prop like it did GRRRRRRRRRRRRRRR.
When it has a reading it is believable but it is certainly not as easy to use now as it was before the crash landing.
Got back to the engine testing and leaned the LSN, I didn't really count but it took multiple turns.
There may still be a little room to lean it some more but like I said I don't want any lean runs on the engine.
When I went back to the HSN it is now peaking at 8910, there is good control of the rpm and I set the HSN to 8370.
Once the LSN was set the overshoot on the WOT rpms has gone away (or maybe the tach is just not working as good as it was).
The engine runs good.
I found the vibration that people have talked about, when reducing throttle ... at 2600 rpm the engine begins to shake violently LOL yes I said violently and continues to do so until I get below 2200 rpm, then it settles down and runs like a very refined machine, take the throttle up very slowly and the shaking repeats beginning right at 2200 and going away at 2600. It is absolutely repeatable every single time. The engine idles great even below 2k, the LSN is very close to being right on the money, and somehow I doubt that this rough spot will go away completely.
With the needles tuned there is still a huge amount of fuel that comes out of the vent port, I have aprox 16" of large fuel line on it right now which was intended to keep me and my stuff cleaner, however it was in the perfect position to soak my shoe with the gunk ... so much for trying to outsmart myself.
OK after that long (no very long) story here is the bottom line:
Saito 125, MA 16x6 K series, 15% Omega, 60 deg F, 500 ft elevation, 24% humidity
Peak 8910
Set to run at 8370
Idle reliably <2k
Aprox 2/3 gallon of fuel run through the engine.
Don't know if this is good or bad for a 120 class engine, the rpm reports on the forums vary so much it is hard to know what is real and what is make believe. Once flying season gets going again I will pay more attention at the field to this engine class.

pmillerusa

Thanks Lou.

It ran for about 30 minutes total. All very low RPM in general, especially at first. The last half of the 2nd tank there was a little more aggressive throttle, but still not even into the 5-8k range.

Between the smoke bath and nitro spay out the exhaust I was still plenty rich I think (not to mention the termite barrier it probably put on the side of my shed [sm=omg_smile.gif] )

One more full tank and then tach-ing it properly is still on the table before it’s ready I think. The airframe has another few months so there isn’t a rush.

Good to hear on the Power Master working well for you… thanks for that.

VF84sluggo

My Feedback: (55)

It's an honor to be admitted! Then again, I wonder about a club that would let somebody like me in it

w8ye

My Feedback: (16)

Actually we felt sorry for you having to drive across that 7 mile long bridge every day.

gzkpez

What is this for http://www.horizonhobby.com/Products...rodID=SAI65156 ? It looks interesting, but I can not tell why they call it that, or gather much from their web page. There are 3 other ones like it, of different sizes.

w8ye

My Feedback: (16)

That's a header pipe to adapt a Hatori tuned pipe to a Saito

Rudolph Hart

That's a nice looking unit dave.What's the weight difference? and are they selling them yet?

Happy new years eve to you all..i'm gonna get really wobbly at the street party here tonight so as a safety precaution i'm going to unplug the puter right now..sighs of relief all round

Ken6PPC

Charlie, I read your story, and one thing in particular jumps out at me. My 1.25 vibrated terribly when it was new, but the vibration went away when I leaned the LSN far enough. Therefore, since your 1.25 is still shaking VIOLENTLY (as you put it), I think you might need to continue working with your LSN.

The proper way to set the LSN is to continue to lean it 1/8 turn at a time, as you test it by going from idle all the way to WOT quickly. When you get to the point where it stutters and almost dies, then you richen it up about 1/4 turn, and leave it there. Until the LSN is set this way, you will NEVER get the best performance your engine can give you, and it will use more fuel and vibrate more than it has to.

I also believe you have to re-tune both needles on a new engine a few times as it gets fully broken in. (Probably after 2 or 3 gallons.)

One more thing... You only have to richen the HSN up a few hundred RPM's from absolute peak. There is no advantage to running it as rich as you are currently.

chashint

I agree with you on all counts Ken6PPC.
Right now I say this engine is a winner even with the 'violent' shaking at 2.3k maybe it will settle down completely with the final LSN adjustment, but if not ......... HAHA ... I don't need no stinking 2.3k rpm anyway
Right now the engine is mounted on my test stand and I am lesiurely playing with it, letting it run itself in slowly. I have not gone for absolute peak on either end yet, and I may not with the Omega fuel.
For my everyday use I have been mixing a gallon of the Omega with four gallons of all synthetic oil fuel (Wildcat and Cool Power), I don't like the castor slime but I still want just a touch of castor in the fuel. I can tell the difference in the exhaust residue with the 1% castor mix so hopefully it is doing something positive for me.
The reason I am going to the trouble of mixing multiple gallons together instead of just adding castor to individual gallons is to keep the total oil content the same.

NM2K

My Feedback: (14)

The apparent shaking is the result of Saito's continued effort to bring you an engine with the best power-to-weight ratio possible. Heavier crankcases damp the vibration via inertia. The vibration is still there, but its effects aren't as visible. Add 20 to 30% nitro laced fuel and a light propeller and all would be amplified yet again, were that the case.

A less than massive and well damped engine mount can also contribute to what appears to be violent shaking.

I know that a lot of you folks already know this information. I am not trying to talk down to you. But we have a lot of newbies everyday joining us and, though intelligent, a little push in the right direction thinking-wise doesn't hurt.

I still prefer to break-in my engines on the bench. Especially Saito engines since they do not need that much break-in time, but they do require a somewhat specific regime for best results.


Ed Cregger

pmillerusa

wanted to share the Rube Golberg test stand and photo opp of the .91....

NM2K

My Feedback: (14)

I would add at least one corner brace to your mount. Then it should be just fine.


Ed Cregger

rlmcnii

My Feedback: (3)

If this engine is putting out FUEL from the crankcase vent it is some distance from being properly tuned. Probably a long distance. And, it will never perform at its best until it is properly tuned.

Peak the HS needle first and ONLY at wide-open throttle. Use a tach to find peak rpm, you will not be able to hear it. Near peak, it may only take one click of the needle to make a noticeable difference. Give the engine a few seconds to adjust to your adjustments.

Once the HS is peaked, and only after it is set, it is time to do the LS. KP66 has suggested one method, and it is a good one. Another method is to set the rpm at high-idle and slowly,but continuously, lean the LS needle until the rpm just begins to sag. As you lean it the rpm will increase; if starting from the new setting, rpm will increase a lot. You may need to readjust the linkage to slow the engine. Once the rpm begins to sag you will know it is a little lean. Back the needle out 1/8 of a turn and advance the throttle. If the engine quits, it is still just a little lean. Open another 1/8 and try it again. After one or two attempts the engine will transition from idle to wide-open with no hesitation...this is the LS setting for which you are looking. You want a good, clean, repeatable, transition. The benefit of leaning the LS until the rpm sags is that it eliminates any ambiguity as to being too lean or too rich; you know it is lean. If the engine dies when you open the throttle, it is still lean. See???

No go back to wide-open and open the HS to drop 100 to 300 rpm from peak. This may take only one or two clicks. Use a tach and be a little patient..let the engine catch up to your adjustments.

One other little thought: If the HS needle has been leaned during the initial 40 minute break-in, it is possible that it will be too lean to permit the engine to go to wide-open with out banging, popping, maybe throwing a prop, and stopping. If this happens go back to the specified HS setting for break in. Do the instructions not say 4 or 5 turns open for an engine larger than 1.00? I know, and I can hear the screaming in cyberland, "that is way too rich.". It sure is, but it will only be used to permit the engine to be safely advanced to full-throttle without any undue excitement. As soon as wide-open is reached the HS needle will begin to be leaned. Hang in there.

As the engine accumulates time you will, as KP66 wrote, be able to fine tune a little more. A well-tuned Saito is not a dirty-running engine. And, you will never know how smoothly the engine will run until it is tuned. And, you will be pleasantly surprised at how little fuel the engine will use!

Omega should be fine; its lubricant is 30% castor, isn't it? It is the fuel upon which my Saitos are successfully run.

Have fun, good luck.

w8ye

My Feedback: (16)

Some Saitos seem to have a false lean peak on the high end. The tach may help yours if this is so.

Some of my Saitos are just juicier than others

VF84sluggo

My Feedback: (55)

Great post! I am a newbie, and this helps...a LOT!

Hobbsy

My Feedback: (102)

The importance of the LS needle being set properly cannot be stressed enough, it controls about 90% of the throttle ranges mixture. Having it too rich causes excess fuel consumption and a shaky, lousy idle and midrange from the rich mixture cooling the glow plug.

blw

My Feedback: (3)

mistermnkim- you are member #625

pmillerusa

Thanks Ed..

That’s certainly next up. I actually thought about not posting the picture until I did just that... (I was thinking – how long before someone mentions the lack of structure there…) funny when your conscious tells you to do something, you should often just do it.

Hobbsy

My Feedback: (102)

The TurboHeader weighs exacly half as much.

Falcon32

Hi w8ye

Thanks for your explanation.
I will try adjusting the needles a little more on the rich side and double check the valve clearances.
Don

mike early

More power? Less weight? More compact mounting requirements? Cheaper than a stock replacement?

Sounds like a no-brainer.

chashint

Probably sounds a lot louder, which may or may not be an issue depending on the flying site.

Rudolph Hart

Thanks dave.Is that a pre-production unit or are they selling them now? i don't see a seperate listing on the site for the 220..same as the 150/180?

cheers
peter