Dumb Newbie Question

[HeliDan]

Hi, Still playing with G3 and some small FP and newly aquired CP, but contemplating a nitro bird. I have nitro monster truck and use 20%. Have been told that the smaller the engine, the more nitro you need. My question is why do helis require a totally different blend of fuel?

thanx

[spork]

My question is why do helis require a totally different blend of fuel?

UH OH! :shock: I'm an old timer. Flown nitro birds for years. I didn't realize they did (require a different blend of fuel).

We typically fly anywhere from 15 to 30% nitro, and 16 to 20% oil. So generally maybe a bit higher oil content (synthetic or castor - but synthetic is probably more common these days) than trucks or planks. Probably more important is to run the heli enough on the rich side that you have plenty of visible smoke. I've always run my bird on straight-up PowerMaster 15% nitro with no worries.

By the way, I haven't flown nitro in a while. Someone please correct me if I'm out of date.


EDIT:

Hey, I just noticed you're just across the bridge from me. We kitesuf at the west side of the San Mateo bridge almost daily (although the season is now winding down rapidly :( ) It'd be great to catch up with you and see where you fly.

[HeliDan]

I did not notice it until read it in HeliMag magazine. But there is a special 'Heli' fuel and I later noticed it in my LHS. I am interested in knowing why, since I would think that a nitro engine is a nitro engine. And why are the heli engines running so incredibly rich. I never see that much smoke from any other nitros.

thanx!

[spork]

I think people are keen on making their heli engines run reliably, last longer, and keep cool (Plank engines hanging out in the breeze are a little easier to keep cool). So I think they tend to run a bit more oil, and run them richer.

The cynic in me says they'd sell left-handed heli-fuel if they thought it was an interesting market. Like I said, I've never put heli-specific fuel in my bird. But I'll certainly let others chime in if I've been messing up all these years.

[BarracudaHockey]

Any fuel with enough oil is fine.

Morgans Cool Power 15 percent is labeled for airplanes, helis and 4 strokes but like colored lures are better for catching fisherman than fish, the only thing different is the label. Some guys will only fly "heli" fuel in their helis.

The red 20 and 30 percent heli mixes indeed use more oil in the fuel.

[spork]

... colored lures are better for catching fisherman than fish...


I like that! That's getting filed in the database right next to

"There are some people you'd rather pay the rent for than live with" :mrgreen:

[flyinfool]

The only significant difference is the oil content.
Heli fuel has the highest oil content.
Car/truck fuel is the lowest oil content.

Helis have much bigger and more expensive engines than do cars.
Car stuff is designed around racing. Racers don't care if they wear out engines faster if it means more power. That's part of the cost of wining.

The oil also carries a lot of heat out of the engine helping that tiny little fan cool the engine.

The helies only look like they are making more smoke because they move slower and the smoke is more concentrated.
If you put the same heli engine on a plank and run the same heli fuel you will not notice nearly as much smoke just because it is spread out more.

Helis also have a very different running environment than any other nitro application.
In a heli the engine is either at idle or flight rpm and is not supposed to change during the flight. All other applications power is rpm dependent so you are constantly changing the rpm. As was mentioned above, planks have great blast of air for cooling where a heli just has a little fan and is buried in the frames.

[spork]

The helies only look like they are making more smoke because they move slower and the smoke is more concentrated.

I'm sure this is true if you run the needle at the same setting, but I tended to intentionally run mine rich. This definitely kept it cooler. Some guys ran theirs so rich they could write their name in the sky at 80 mph.

[flyinfool]

I typically have enough smoke that I can still see the smoke trail from the beginning as I come around the bottom of a loop.

80 mph is pushing the world speed record for a heli. We typically are flying at 40-50 in FFF. A plank will easily hit 80+.

[spork]

80 mph is pushing the world speed record for a heli. We typically are flying at 40-50 in FFF. A plank will easily hit 80+.

I clocked my old X-Cell at 78 on a police radar years ago. Perhaps the radar was faulty - but I would've guessed it was somewhere in the 75 to 80 range.

Some full scale helis can approach 250mph

FAI record: "Speed over a straight 15/25 km course : 400.87 km/h"

[BAyres]

Okay...here is another newbie question for the Raptor enthuiasts.
I have been pretty set on getting a Raptor 50 Titan as my first heli. But, as usually the case, I found a JR Venture 50 with Hyper 50, digital servos all around, and 401 gyro already installed. The owner flyes at our field, and everyone has told me he is very meticulous with his planes and helis, so I know it's in excellent condition. He told me he wanted to get rid of it because it is "too stable." Is $470 a good deal, or should I wait and get the Raptor 50? Opinions needed!
I also located a JR8103 radio at the same shop, but the servos the owner is trying to get rid of are very old. He wants $275 for it? Opinions again needed. Buying a used radio from an unknown owner??? Help!

[HeliDan]

Hey, I just noticed you're just across the bridge from me. We kitesurf at the west side of the San Mateo bridge almost daily (although the season is now winding down rapidly :( ) It'd be great to catch up with you and see where you fly.

Give me a PM to let me know exactly where. and what is kitesurf? Is that the water skis that get pulled around by a hang-glider kind of affair? I am not yet a member of the club I plan to join, I fly in this park that is basically 20 feet from my house. But I will join soon as I know I will need lots of help from people who can actually look at what I gave built and tell me how I screwed it up :oops: .

Thanx

[Rickenbacker]

Okay...here is another newbie question for the Raptor enthuiasts.
I have been pretty set on getting a Raptor 50 Titan as my first heli. But, as usually the case, I found a JR Venture 50 with Hyper 50, digital servos all around, and 401 gyro already installed. The owner flyes at our field, and everyone has told me he is very meticulous with his planes and helis, so I know it's in excellent condition. He told me he wanted to get rid of it because it is "too stable." Is $470 a good deal, or should I wait and get the Raptor 50? Opinions needed!
I also located a JR8103 radio at the same shop, but the servos the owner is trying to get rid of are very old. He wants $275 for it? Opinions again needed. Buying a used radio from an unknown owner??? Help!

Well, I'd get it. If you don't like the heli you have all the parts you need to kit ut a new Raptor, and cheap too :-).

[spork]

Give me a PM to let me know exactly where. and what is kitesurf?

Kitesurfing involves using a big kite (14 square meters) to pull you on a wakeboard and cause you to jump 30+ feet high in good winds. You can see this at the west end of the San Mateo bridge any day there's wind (which is most any day from April through Oct).