Nitro fuel?

[Jlitz3]

I’m wondering what is the best nitro fuel percentage is for OS50 is? Also dose it need to be 30%? Thank you and any help would be great.

[Dyehard]

The OS 50 will run on 15% fuel just fine, but it will make more power and be easier to tune on 30%. If you are just mostly hovering and doing mild aerobatics, 15% will work, but I like 30% for the tuneability. It's just easier to get the engine to run steady without having to really lean it out and I get less flameouts after an extended idle.

[Jlitz3]

Thank you for your response, I will consider that choice and give it a try.

[Ken Here]

more info here, hope this helps. I was reading up too
https://www.helifreak.com/showthread.php?t=854427

[rcjames]

Originally Posted by Jlitz3

I’m wondering what is the best nitro fuel percentage is for OS50 is? Also dose it need to be 30%? Thank you and any help would be great.

I actually have a os 50 like u that isn't a hyper. Hyper has just a better head for cooling and better carburettor. Came with my raptor 50 v1 that i just bought not so long ago. I live in Fresno and Hobby Town don't have our fuel. And Amain Hobbies don't have single gallon of heli fuel. So I bought from Amazon Torco Rc Fuel 20% Helicopter Heli Gallon. If you want reliable long lasting engine. Don't run higher nitro. And higher nitro is only good if ur gonna be doing 3d stuff which I'm not. I bought this fuel for 39.85. 20 percent of nitro with 22% percent oil. I notice that fuel is also higher price. So I think this is actually decent price. Good reviews. Toki 40 is a powerful engine for a 30 size. If you read review the guy with toki 40 is actually happy with the fuel. Toki 40 hard to tune. So I bought the fuel. Wish fuel was lower and actually be selling locally instead plank or car fuel.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[rcjames]

Originally Posted by Dyehard

The OS 50 will run on 15% fuel just fine, but it will make more power and be easier to tune on 30%. If you are just mostly hovering and doing mild aerobatics, 15% will work, but I like 30% for the tuneability. It's just easier to get the engine to run steady without having to really lean it out and I get less flameouts after an extended idle.

But 30 percent runs hotter on engine and not ideal if u want an engine to last for couple years LOL

[Dyehard]

Originally Posted by rcjames

But 30 percent runs hotter on engine and not ideal if u want an engine to last for couple years LOL

30% fuel will not make an engine run hotter, unless you are setting the high needle too lean, and that is true of any fuel. 30% nitro fuel will allow you to set the mixture richer than 15 or 20 percent fuel and make the same power, which means the the engine will actually run a bit cooler. I have four stroke engines in 3D planes that have run for close to 15 years on 30% heli fuel and still make as much power as they did new. I have heli two strokes that have run for years too. I always keep them a little rich and they come down cool after a flight.

[RRRoamer]

Originally Posted by rcjames

But 30 percent runs hotter on engine and not ideal if u want an engine to last for couple years LOL

Not necessarily. I live about a mile up. Here, the compression is down (not ratio, pressure) due to 12% less air up here. If you run lower nitro fuel, you end up having to lean the engine out more to get it to run right (remember, nitro engines ignition timing is determined by pressure and heat in the chamber, so as altitude increases, ignition timing decreases with everything else remaining the same). That leads to an engine that is running hotter (leaner, delayed timing) than if you ran it with more "liquid air" with a richer mixture (relative and absolute richer) and better timing.


Many years ago, I tried an experiment with a Picco .15 RC car engine (again, a mile up). I normally ran 30% nitro in it and ended up buying a gallon of 20% (same brand, same oil package and %) as my LHS was out of the 30% I normally ran. In short, the engine ran like crap! Couldn't get it to idle (it was on the harry edge all the time. And yes, I had already removed head shim when I first got it due to the altitude). It was always trying to overheat. And it was down on power.


So I went back and bought a gallon of 40% to play with. That really woke the engine up! Ran nice and cool, wasn't particularly sensitive to needle settings, and hit like a sledge hammer.


When that gallon was gone, I found myself dragging home a gallon of 45%... Mostly the same as the 40%, only a bit more heat and even more power. At that point, the RC10GT truck it was in was WAY over powered. But that little Picco .15 ran GREAT!


Now, this statement is only really true at high altitudes where your ignition timing is getting messed up due to low cylinder pressure. I'm sure if I lived near seal level, I would have a lot of the "runs hot, will ruin the engine" problems on higher nitro fuel as many others have had.


But at high altitude, nitro is your friend.