Maiden flight today of my Hobbico Twinstar. Saito .30FS engines. Near disaster. Spent some time syncing up the engines, should have refilled the tanks. Ran the left engine longer than the right, left tank ran dry during a loop. I have no idea how I got that sucker back into shape and down on the deck but did with no damage other than to my shorts. I am running both engines pretty rich due to newness of the engines so the flight duration was very short especially that left engine. Got it all on video, will post the link later if any are interested.
The Saito 30 is a terrible gas hog. I used one on a Guppy when it first hit the market. I thought that I had some mysterious problem because I just couldn't get it to run right. It turned out that it had sucked the fuel down to the dregs, and it was giving me a lot of trouble as I tried to get the needle valve set properly. I never imagined that it had run out of fuel because I had run it less than 10 minutes. After I figured it out, I switched over to an OS 26. Same amount of power, 4 times the endurance with the same propeller and same tank. I would never put saito 30s on a twin unless I had room for ten ounce tanks, because I can't think of an engine more likely to run out of fuel in-flight than the Saito 30.
I wouldn't mind seeing the video. It sounds exciting.
Syncing the engines via mixture needles on a model is a bad move.
Being glow engines, with fixed timing, you tune each engine to run its individual best and then put up with it being out of sync, unless you are using an electronic synchronizing gizmo on the fastest engine. But, even with the latter, you set up each engine to run its best and then let the gizmo slow down the fastest engine to match the slower engine.
I bought two OS. FS-30 engines a short while back for my Twinstar ARF. I know, everyone says that it is not enough power, but I just have to try. I have two ST .34's waiting in the wings if it does prove to be underpowered with the four-strokes. I'm not looking for aerobatic performance above what a full size twin of the same genre' could deliver.
Here's how I got everything to run properly on my OS 20FP trimotor Telemaster. First I set the throttle arms to the same position on each engine. In other words, at mid travel the throttle arm pointed straight down. Then on each engine I set the optimum fuel mixture for dependable running. This was done with each engine running individually, with no consideration given to synchronizing peak RPM. Then I set the servo linkage on each engine so that all three engines would die at the same throttle trim setting on the transmitter. That way I could pull the stick down to idle and be sure that nothing was going to die, until I pulled back on the trim tab and they all three died at the same time.
With the engines set this way, their performance at low throttle was very close to being the same across the board. At high throttle there was some variation but when the plane is flying fast, the airstream straightens it out.
I used the same method to set up a four engine Bud Nosen Trainer powered by OS 26 four strokes. The engine handling was impeccable, but the plane was way overpowered. It could barely taxi at idle without achieving takeoff speed. I didn't like that plane much. It needed an old 60, like the kind it was designed for.