irishcarbomb

My Feedback: (4)

I just recently purchased a Saito .72, and was wondering if anyone could offer any advice on breaking-in, tuning, fuel, or any little tips/tricks. anything will be greatly appreciated.
thanks
rob

Hobbsy

My Feedback: (102)

Roar, I tried to respond to your question a couple of minutes ago but my response got lost before it posted. Just put a 13x6 on your .72 and run it slightly rich at 4,000 rpm for about 20 minutes, at about this point you'll hear it start to speed up a little then speed it up to 5,500 and finish off a 12oz tank, I use Wildcat Premium Plus at 10% nitro. When that tank is done I usually fill it and run the engine alternating between 6,000, 7,500 and wide open every few minutes. If it came with the new silver looking Hangar 9 Super Plug it is as good as or maybe better than the OS-F. At this point it is nowhere near broken in but will fly very reliable. To set the top end use a tach and peak it then richen the speed down about 200 rpm, set low end for best idle and transition. Don't move the low speed needle very much at one time and let each setting stabilize before changing it again, four strokes don't respond to needle changes instantly and you can end up chasing your tail and thinking there is something wrong with your engine. I have nine Saitos and have never needed on board glow heat using the Fox Miracle Plug or the new H9 Super Plug, hope this is not too long winded.

Mr. Wildcat

Last poster got it partially right. He implies that you run it at partial throttle (4000-5000 rpm). Instead, you should break in your ringed engine at full throttle and set needle valve SO RICH that it runs at 4000-5000 rpm) You may need to leave glow drive on at this rich setting. The ring and low end needs the extra lube until they become properly mated. You should use a good 20% fuel which has a little castor in it.

Hobbsy

My Feedback: (102)

I wrote precisely what the Saito manual says for all their engines, with throttle at 1/4 to 1/3 open it says in bold letters do NOT exceed 4,000 rpm for first ten minutes of operation. After that the mixture can be leaned out slightly and be considered broken in after 40 minutes, which is about how long it takes to burn two 12 oz tanks. My wife got me a Saito 100 GK for Christams so I had the manual right here.

mglavin

My Feedback: (31)

I believe the key ingredient to proper engine break-in is heat-cycling. Heat-cycling allows the engines dissimilar metals a chance to become acquainted with one another.

The reasoning behind engine break-in is simple in concept.

Most engines run at higher operating temperatures when new. This is caused by the friction generated by the various metals/working surfaces interaction with one another. Add to this the heat generated during the normal combustion process.

The goal is to provide adequate cooling during the break-in procedure. There are two accepted methods are:

1] Excessive unburnt fuel/oil mixture allowing the engine to run considerably cooler.

2] Reduction in prop loads will cause the engine to turn higher rpm while creating less heat. Less heat is realized by the decreased cylinder pressures realized at higher rpm's.

Castor oil is not required for engine break-in but will not harm anything either. I suggest a fuel with a blended oil package.
I use 20% oil by volume my YS Engines 95% synthetic - 5% castor. Saito's are run with 16% oil by volume, again 95% synthetic - 5% castor oil.

I would also suggest that you use the fuel you intend to fly the model with for the break-in process.

My preferred break-in procedure is as follows for ringed engines:

Start and operate the engine for approximately six intervals, running the engine rich, allow the engine to come up to operating temperature each time, about one minute run time. Allow the engine to cool-off in between runs, usually about 10 minutes.

Again run the engine rich as before with the same procedure this time run the engine for about five minutes, lets say three times allowing the engine to completely cool between runs.

Once the above has been accomplished, fire the engine, warm it up and adjust the needle to obtain maximum rpm, as measured with a tachometer, back off the needle until you see a 400-500 rpm drop and fly away. You can now complete the break-in period while enjoying the model...

Hobbsy

My Feedback: (102)

Mr. Glavin, I think I mentioned above that I have nine Saitos and have not ruined one yet following their instructions. Saitos instructions are geared toward getting the engine capable of flying, flying has heating and cooling cycles built right into it. I'm not being combative, just don't think what I wrote needed rewritten.

mglavin

My Feedback: (31)

Dave

I provided my opinion on engine break-in. This is specifically what the original poster asked for... I find no fault with your procedure, I have become accustomed to doing things my own way, as I am sure you and the rest of us has as well.

Heat-Cycling is not achieved by running the engine as you suggest, albeit there is some benefit done as such...

The instability of specific materials/metals used in the construction of our engines requires additional final stress relief. This is achieved by repeated heating and cooling within the engine. To what extent this is accomplished by running the engine continuously, say for 20 minutes or more is questionable. The correct approach is short duration heating and adequate cooling intervals, when the engine is new and first run.

For the record I have:

7] Saitos.
14] YS Engines four Strokes, or more.
9] OS four strokes.
2] Saito twins.
2] OS twins.


I have never, had an engine failure that was not the result of 80% nitro and or fatigue caused by the use and abuse of the engine in my racing program.

Hobbsy

My Feedback: (102)

I apologize for reading more into your post than you actually said, that said, in your response you made reference to high nitro use in Saitos, Ive had two aquaintances who've blown up Saitos on 30%, one an .80 blew the cylinder loose on one side of the crankcase and the other a 150 shoved the rear main bearing partway out the bottom of the crankcase. Did yours suffer a similar fate? I've never used over 15% nitro in any of mine. Mostly I use 10% in my newer ones and 5% in an older high compression .80 and 150.

mglavin

My Feedback: (31)

Dave

I have never ran anymore than 30% fuel in my Saito's, and just as an experiment. I had no problems and am aware of many doing so on a regular basis, with no problems, other than taking out second's on their homes for fuel purchases. Saitos make poor race engines, but work exceptionally well as sport engine IMO.

I only use the YS Engines for racing. Have you ever heard a
'80% nitro fire breathing top fuel' Mustang fly by at 160mph? What an incredible sound. The YS's hold up well for a short period of time, and then need a minor rebuild. I generally run 45% fuel, I have found the engines provide reliable horsepower without damaging themselves with such.

sport10

I have a Satio .91S that I run on Morgan's 30% heli fuel. The engine loves this fuel and seems to actually run cooler. The heli fuel does have a higher percentage of synthetic oil. It is around 22 to 23 percent. The power gain over 15% is quite noticable and it improves the idle and transition to boot. The people at Horizon have been running 30% Heli in their satios for quite sometime now without any problems.