1/4 turn on high speed Saito 1.20 makes engine quit ?
 

Have a new Saito 1.20 mounted in my Hangar 9 Christen Eagle II. Ran the engine at home before going to the flying field and everything was fine, except had to cut back slightly on the low speed idle, which was an easy adjustment.

Got to the flying field and once again engine was running fine all the way from idle to high speed. Thought that it sounded a little off on the high speed, thus I thought that I would lean it about a quarter of a turn. Made the adjustment and advanced the throttle to high speed and Whaaaaaaaaaaa Laaaaaaaaaaaaaaa, the engine quits, which surprised me !

Hard to believe that even a quarter of a turn leaner on the high speed needle would cause it to quit. Unless of course I was already at the high lean end of the spectrum and perhaps until total break in, I should be running the engine much richer.

I have always made it a practice with all my engines to run them on the richer side, even after break in.

Any opinions from the experts ?

A quarter turn lean is a lot, it's not so much when turned richer. Use a tach, find the peak and then go about 200 rpm rich. I always thought 300 rpm rich is too rich. I ain't a ekspurt I jis dun it a lot.

I agree with Hobbsy. 1/4 turn is a LOT. I would normally suggest 1/16th of a turn at a time if there isn't a good detent "click" to be felt or heard.

Really surprised me that it quit with just a 1/4 turn. Have to make a few adjustments and improvements before the next flight, but I will be going back to original high speed setting. Also, I agree that I will be putting a tach on it and then backing it off another 300 to 400 RPMS.

One of the adjustments that I have to make with this model is to add some down thrust. Maiden flight was mostly flown at half throttle. If I even came close to full throttle, it wanted to climb like a rocket. Thus, assuming it does need some down thrust. :rolleyes:

Normal procedure is to go 2 "clicks" on the HSN & wait for the engine to stabilize before going further. 1/4 turn, on an engine that is probably already near the peak RPM setting is HUGE!

I agree with the rest that 1/4 turn is a big adjustment. Now to the trim issue. Do yourself a huge favor and make NO adjustments until you measure everything and check your CG. For an aerobatic bipe I really like the settings that Goldberg used on their Ultimate. Those settings are engine at zero, both wings at zero and stab at + 2 degrees. I would be interested in knowing what H9 has the CE set up at. Another thing to consider is CG. If you are nose heavy and it required up trim even at 1/2 throttle then at the higher airspeed that trim becomes more effective and she climbs. Did it seem to want to land fast? If yes, that is another sign of being nose heavy.

Yup. A 1/4 turn is not "just". It's a huge adjustment.

When tuning the low speed needle, baby steps are required, not the high hurdles.:)

As to peaking a Saito, you're best bet is to sneak up on the peak, (as stated above) and per Dan's suggestion and give a few seconds between changes to stabilize. I've been pooh poohed pretty hard for that suggestion but it prevents kicking the prop off. I am surprised yours didn't shed its prop when leaned the additional quarter turn. If I tried that with my 1.50 I'd have to walk over to the neighbors to get my prop back. Here's an example. This prop bounced off of my sons deer stand and then into my wood pile. I had to order new nuts.

PS, Dan, the nuts came very quickly form Lantz Hobbies.

I use a jamb nut behind a spinner nut on my engines. Had one prop go for a flight on its own one time, only had the single prop nut that time. Haven't lost a prop since I started "double-nutting" the prop.

So just how new is this Saito? If you have less than a gallon of fuel run thru it, you should NOT be at the point where you need to tach it at High RPM. You should still be running it rich. And I agree with the 2 clicks at a time. Good luck.

Could not fly it at all at full throttle as the climb angle and rate of climb got ridiculous. At half throttle, I was adding down trim. For your last question, it did not appear to be landing fast at all. As a matter of fact it was at a good controllable airspeed with very little control inputs.

As for other questions from other folks, it is a new engine with basically 1/2 gallon burned thru it. Will be going back to original settings and adjust a click or two at a time and with a tach. Should have just stuck with my golden rule as to running all of my engines on the rich side.

At a half gallon, your Saito still needs breakin time. I'd try to get it running reliably, and leave the tach in the tool box. Your engine is not ready for peak performance at this point.

Dave, I don't know why anyone would give you a hard time for that advice. I read somewhere, maybe a Clarence Lee review, to give a 4 stroke 12 seconds to settle after a change to the high speed needle. I don't know about the 12 second part, but you are certainly right about letting the engine settle.

Good advice, Tom. At this point, you are tuning to get close but your tuning will change as the engine wears a little more as it continues to break in. Frequent tuning tweeks is normal for some Saitos, and others will hold a tune longer but they all drift some over time. Suddenly, after a gallon or whatever, you notice the engine is smoother than any other brand and reminds you of a fine piece of machinery, like a Swiss watch. That's when you know for sure it's broken in.

To me this would indicate being a tad on the tail heavy side. Up trim says nose heavy and will want to climb when trimmed at half throttle and more power is applied. Down trim says tail heavy and airplane will want to climb no matter what the power is and in some cases will drop the tail at slower speeds.

Thanks Barry, another Hobbservation I've made over the years is that, at the absolute peak, one more click lean wiil knock about 50 rpm off the tach reading. Two clicks lean and you need a new prop and nuts. Incidently, the broken prop shown above was held on by a conical nut that seats into the prop washer and a Tru-Turn adapter like the one on there in the picture.

I am placing CD ignition on a new Saito 1.50. I plan to run it on my own blend of fuel...no nitro, race grade alky with Klotz oil. Also will add a tad of Beenzoil . What do you thing Hobbsy? Thanks Capt,n PS not looking for top power...it will power a real lite airplane.