Not24 You and plenty of other guys think one size fits all mentallity. Another words all engines will run 15% nitro. Yes you can get a ST to run 15% but not at 100% reliabilty. They will suck more fuel and need more weather related tuning and deadstick at odd times. You have a massive thread on a ST2300 and I think half your troubles was stubburness to drop off your beloved 15%...........I just proved this nitro rule to a flyer yesturday with a FOX 50 and his 15% nitro. I told him you have to realize DUKE FOX prided himself on getting the ultimate performance from 0% nitro. The Fox RC long idle bar was invented for these engines. The engine was not reliable in the air. I said lets do 2 things. Put in a fox idle bar and tune on my 5% nitro. The engine never quit again and would idle for ever now. It actually turned better RPM with lower nitro. I'll guarantee if more flyers limited nitro to 10% or lower on a Super Tigre they will love the ST line of engines. I know it is almost impossible to buy 5% nitro from a LHS now a days. The old ST manuals did not recommend up to 15% nitro and the chinese engines are exactly the same as the Italian counterparts. I know I'm wasting my time and preaching to the chior...........

We have two guys at the field that have switched to 30% nitro and OS F plugs for all their engines, including Super Tigres. They say that they have no more deadsticks and that their engines run great. I asked them if they had detonation issues and they said no. It's working for them for some reason. Go figure.

Well, since you brought up the 2300 thread, I will remind you that during my nitro tests I found that the engine ran cooler on 15% than on 5%. It also ran much much better. I used several glow plugs and took the time to adjust both needles meticulously for each condition. I'm saying that my G90 runs fine on 15%, and because it does, I have no cause for extensive testing. If it were to ever give me any sort of trouble, I would try other combinations till I was satisfied that I was getting the best overall results.

By the way, I'll soon be reviving that old 2300 thread as I have more things to try. I bought a new carb barrel for the stock carb so I can get back to square one. I modified the metering slot in the original one and never had any luck.

Flame suit on: I have multiple ST 40's, 45's, 51's and three 90's. One has a Nitro Pipe (unmuffled) on it. Each has been run on everything from 5% to 30% and each and every one performed flawlessly on ALL of the different amounts of Nitro. I won't go into settings, prop sizes, glow plug selection or any other specifics but I will say that properly tuned the G90 WILL run absolutely GREAT on 15%. Does it need it? Depends on what you are trying to accomplish. That's my two cents.

I run 15% Omega and 13/8 apc. As far as the 2300, I have that two and the stubborness to me is the ability to properly tune and engine. There is no way anybody cannot perfectly tune one of these.

A Caveman can do it!

There are many factors involved in today's varied flying styles that can induce or reduce the proclivity toward preignition/detonation. Even just a change in the person tweaking the needles makes a big difference.

When we all flew either scale, sport, pattern or pylon, it was easy to issue generalized edicts and for them to hold up as being absolutely true for many years. Not so today. Unfortunately, once in the habit of issueing edicts, it is a very difficult habit to break. It is always done with the best of intentions, however, so give we older fellows a break.

In the early Seventies, which was like yesterday to many of us, the Super Tigre G60 Bluehead would sizzle and fry on a warm humid day if ran on fuel with much more than 5% nitro. This happened. It's no one's imagination or hallucination. It used to cause me physical pain to see fellows install a brand new, never ran, G60 Bluehead into a scale model with a tightly enclosed/poorly ventilated cowl, fuel it with 15% nitro, install an over sized prop to clear thescale cowl and then start it up, only to peak it out for the first flight. Invariably, if the engine did not overheat and quit before they decided to land, it surely would sit there in the pits smoking and making krinking/tinking noises as it cooled down. Another brand new engine had been doomed to a life time of less performance than it was capable of performing had it been broken-in properly with the compression adjusted for the amount of nitro being used and the size of the propeller being employed.

Then the fellows that abused these engines in such a way bad-mouthed the brand and model of the engine as being junk. Thankfully, most folks hearing these stories already knew the teller's disposition, so no one actually believed what they said anyway.

Once you have heard the sizzle (while running) and the krinkling sound (after running), it will never leave your memory.

Things DO change over time, however, so not every old edict remains in effect for a given engine brand forever. With our old friend, "a ganging of tolerances", it is quite possible that some engines come from the factory with the perfect compression for running 30% nitro fuel. It is also possible that the next engine off the production line might have a problem with fuel containing only 10% nitro. It is the luck of the draw. The important thing is to recognize the symptoms and to then know what to do about them.


Ed Cregger

The modern Super Tiger engines will run well on 5-15% nitro, no question about it. I seen some on here suggest low nitro for Tigers but it has been my experience with these particular engines (51, 61, 90, 2300) that they will run well on 5-15%. I use 5-10% in the summer months.

I'm with you on the .51 and the .61. I have used both 10 and 15 percent nitro with no problems. Same for my .40 ringed. My .90 has about a half a gallon through it on 10% only. For me an A3 plug seems to work the best. In the air it was hard to tell the difference between the 10 and 15%. Can't remember if the 15% had a higher number on the tach, but I do remember no big increase in performance in the air. General sport flying and 3D/hovering.