N1EDM

My Feedback: (2)

The link says that the video is not available.

I ran the S-90 today and got a surprise. It almost surprised me when it started up because it was so quick. I barely touched the starter to it. Then I tach'd the engine at 11,600RPM on a 13x6 prop. And THEN we noticed that I hadn't tightened the glow plug down, so I was running with less than optimum compression to boot! We re-started the engine but my tach refused to operate (low battery). I rebuilt that engine for my buddy and he's happy with it.

Now, I need to get a replacement muffler and pressure nipples for the S-75, my own engine. That should be interesting.

Bob

1QwkSport2.5r

The link is working fine for me on my computer and my smartphone. Must be a fluke. I'll look into it.

11,600 on a 13x6 is low for that engine I think, especially on a wood prop. The stock "swing" muffler is what I was using and tached 12,600rpm on a 13x6 APC and 13,600rpm on a 12x6 APC.

N1EDM

My Feedback: (2)

I had an older style swing muffler but the lower RPM is probably due to the fact that the glow plug had been inadvertently left loose. In fact, by the time I saw it, it was almost out of the head. But, I'm sure that it didn't start out that way. It also gulped fuel like crazy until I tightened the plug. It was a standard OS #8, I think.

Bob

1QwkSport2.5r

Run a hotter long reach plug in that engine and you'll likely see a difference. I like McCoy MC59s in mine but a 4-cycle plug works well too.

And yes, these .90's will suck fuel. Mine went through a 16oz tank in about 6 minutes during break-in.

N1EDM

My Feedback: (2)

Thanks for the heads-up about the fuel.

Bob

1QwkSport2.5r

Be glad you don't have to use 15% nitro in that thing. My Jett .35 on 15% rivals the SuperTigre S90 on 5% in fuel consumption.

N1EDM

My Feedback: (2)

I generally run 10% which I think is a good compromise. That's what I made the test run with yesterday.

Bob

1QwkSport2.5r

I don't know what your elevation is, but you might be able to get away with 10% with the S-series ST's. My S90 does not like more than 5%, period. If I had it in a plane when I tried 10 & 15% nitro, I'd have a broken plane and probably a broken engine. Deadsticks aplenty. The 90 has to be set about 700rpm down from peak on a full tank to not lean out too far. I use the pinch method for setting the needle as 400-500rpm rich (3-4 clicks) wasn't rich enough I found. At least as my 900' ASL elevation anyway. I lose about 1,000rpm as compared to someone at sea level using the same engine, prop, plug, and fuel.

Just a little perspective. Good luck with your Tigres. I like mine a lot better now than I did when I broke them in.

N1EDM

My Feedback: (2)

I've had SuperTigres for a long time... We fly at sea level here and I've never had a problem using 10% fuel...

Bob

1QwkSport2.5r

I must have a picky one then. I couldn't get my S90 to run for beans on 10% or 15%. After 2 gallons of 5% fuel, it throttles really nice. Up to that point, the midrange was less than ideal without having the spraybar tweaked really far.

My S29 and G51 (both Italian) ran okay on 8% nitro so I'm sure 10% would be O.K., though I'm a cheapskate and stick to 5%. The S29 is piped and runs fantastic on low nitro fuel.

The Jett and my RC car engines are the nitro burners. I run 15-20% in those engines.

N1EDM

My Feedback: (2)

OK