Nitro Fuel

[skene]

Hi there. Today I bought an HPI Rush Evo, and went to buy some fuel. I'd been reading up on them and know that HPI recommend 20% fuel for it. But the shop I bought it from only stocked 20% Helicopter fuel, so long story short, bought that. Doesnt run on it but runs on a mates fuel. Whats the difference?

[sgrimshaw]

What fuel is it?

Many makers fuel is suitable for Helis, Planes, Cars etc.

[tr7v8]

Should run on it, sometimes engines can run better on one make over another but it should at least run. 20% nitro is 20%! Might need carb adjustments though, but this will be required if the weather changes, fuel changes etc.

[roger1197]

Nitro Heli.............totally different motor from Nitro car, RPM'S/Lube/carb settings, buy 20% - 25% car Nitro, flush the Heli Nitro from the car fuel system

[skene]

Thanks guys, went back to the shop and bought the buggy fuel which they said they didnt have! And now it runs fine.

[Roop]

Helicopter fuel is a different blend altogether. Mainly because helicopters run virtually flat out all of the time with marginal cooling, so the fuel itself is designed to protect and cool the motor under heavy load, high rpm and high temperature running.

Always use buggy fuel in a buggy (as you have found out).

[tr7v8]

Interesting 20% nitro fuel will be 20% nitro, around 25% lube & the rest is methanol. The lube may vary but car & heli have similar requirements, very high revs, limited cooling. So cannot see why it'll be different & I've been running glow motors for years.

[Roop]

tr7v8 said:

Interesting 20% nitro fuel will be 20% nitro, around 25% lube & the rest is methanol. The lube may vary but car & heli have similar requirements, very high revs, limited cooling. So cannot see why it'll be different & I've been running glow motors for years.

The motors themselves are quite different because the requirements are different. Car cooling is much better than heli cooling - the head on a .21 buggy motor is typically twice the area of a .50 size heli motor (!) The car motors must deliver across a reasonably wide power band whereas the helis are all top 20% of the rev range. Cars are typically variable rpm, whereas heli motors sit at peak power rpm or thereabouts during an entire 10 minute flight or whatever - especially if they are fitted with governors.

[skene]

Cheers lads, learning a lot here! Bought it thinking they are cool and would be a lot of fun. Well they are fun by my god is there a lot of work to get/keep it going.

[philnotts]

http://www.rcmo.co.uk/fuel/nitro-fuel/car-nitro-fu...

phil

[tr7v8]

Roop said:

tr7v8 said:

Interesting 20% nitro fuel will be 20% nitro, around 25% lube & the rest is methanol. The lube may vary but car & heli have similar requirements, very high revs, limited cooling. So cannot see why it'll be different & I've been running glow motors for years.

The motors themselves are quite different because the requirements are different. Car cooling is much better than heli cooling - the head on a .21 buggy motor is typically twice the area of a .50 size heli motor (!) The car motors must deliver across a reasonably wide power band whereas the helis are all top 20% of the rev range. Cars are typically variable rpm, whereas heli motors sit at peak power rpm or thereabouts during an entire 10 minute flight or whatever - especially if they are fitted with governors.

Agree with that to a certain extent although helis don't get over revved like car motors do & because of the torque requirement to spin the head up. But the fuel would be close enough to run it. He said in the OP that it wouldn't run at all!

[Roop]

tr7v8 said:

Roop said:

tr7v8 said:

Interesting 20% nitro fuel will be 20% nitro, around 25% lube & the rest is methanol. The lube may vary but car & heli have similar requirements, very high revs, limited cooling. So cannot see why it'll be different & I've been running glow motors for years.

The motors themselves are quite different because the requirements are different. Car cooling is much better than heli cooling - the head on a .21 buggy motor is typically twice the area of a .50 size heli motor (!) The car motors must deliver across a reasonably wide power band whereas the helis are all top 20% of the rev range. Cars are typically variable rpm, whereas heli motors sit at peak power rpm or thereabouts during an entire 10 minute flight or whatever - especially if they are fitted with governors.

Agree with that to a certain extent although helis don't get over revved like car motors do & because of the torque requirement to spin the head up. But the fuel would be close enough to run it. He said in the OP that it wouldn't run at all!

Agreed. I'm sure it'd run, but maybe not with the out-of-the-box break-in settings.