I have a Superstar 40 with an O.S Max .40 engine. I'm using the pink fuel and was wondering if I can switch to a different fuel safely to get more power and speed out of my plane?

Te color of the fuel doens't dictate it's nitro content. What % of nitro are you using? Higher nitro will give more power, but don't expect a lot.

You should/could be using 10-15% nitro. Going to a higher percentage will be harder on the engine without a significant power increase.

What prop do you have on the engine? A 10x6 is common in that size engine. A 10x7 would give a little more speed but you would sacrifice some of the vertical ability.

Thanks for your replies. Guess the best and safest thing would be to go to a .46 engine.

Larger engine…Yes, there generally isn't a good substitute for displacement. While technically high nitro fuel will deliver more power, a lot is dependent upon the engine design. Most sport engines found in the states are designed for nitro in the 5%-15% range. Running a high nitro mix (like 30%) in sport engines often does not produce the desired results. On the other hand, a high performance engine that feeds on high nitro often will run like crap on 15%. Got to match the fuel to the engine.

I’d like to amplify on what bruce88123 touched on, power doesn’t do any good unless you can get that power delivered to the prop. Prop selection alone can often totally change a plane’s performance. I've seen a few who get larger engines only to be disappointed in the performance do to poor prop selection.

Cheers.

You could try a tuned pipe to pull a little bit more power out of the engine too. As long as ur field doesn't have noise restrictions that would prohibit this.
-John

play this the prop.

try a 9x7 or 9x8. you'll loose vertical but speed will increase.

I've also used 9.5 X 6 props with some results on a 40 but the better deal would be the 46. ENJOY !!! RED

I run 11-5's on all my .40's. You lose a little speed, but it'll have your superstar off the ground in less than half the distance of a 10-6, and you'll have that extra little umph you need to pull it out of a tight spot, and ii'll idle a bit better. You can also pull the baffle out of the exhaust and still keep enough pressure in your fuel tank. I use Byrons 10%nitro 16% oil. I've heard that some manufacturers put additives in the fuel to darken it so that it's easier to see in the lines, but that it takes away from overall performance. *shrug* But I don't know, I've never tried them.

I largely agree -- except that this is an LA that's being discussed. It will fly around just fine on an 11-5 but it is a bit over-propped. An 11-4 will give even better performance with that plane/engine combo. It won't lose much speed, but it will get all of the take-off & climb performance that engine can deliver to the Superstar airframe.

Brit - where did he say anything about being an "LA" engine? OS made quite a few non-LA engines (as you well know)

Doh---- You're quite right. I just assumed (that is a bad word) that it was a Superstar RTF.

Me a dumb***** -- sorry.

It may be an RTF, we just don't know.

So, Alladin,

Help out Bruce and Britbat by further defining your engine.

IMHO, if it is a bushing OS, LA or FP, I use 11 X4. If BB, FX or SF, 11 X 5 is good. That will give you thrust.

If you are looking for speed, get another airframe. On something like the Viper ARF, you can use 9X 6 and go much faster than with the Superstar.

Good luck.

Heck of a deal to be missunderstood in one of these forums.

Ken, AMA 19352