Raptor with a drink problem

[Si Goodchild]

Guys,

Took my Raptor out this weekend for a couple of tanks and was struck by the contrast in fuel consumption between mine and that of another Raptor 50 undergoing "enthusiastic" flying. Now I'm new to nitros so I hve nothing to campare with but by 50 gets through a tank of 10% nitro in about 5 minutes (my first ever fuel purchase and recommended as adequate power for learning). Andy has kindly help me set up and assures me that the mixture is about right, but his machine went on to fly for about 10-15 minutes using what looked like Magnum Fuel (although I didn't clock the % nitro content). My next gallon of Model Technics fuel has already been bought and it's 20% nitro (although it's unopened and could be returned for an upgrade if you recommend).

So I'd apprecite the forum's thoughts on the following questions:

• Is the heavy fuel consumption likely to be due to the low nitro content of my original fuel and therefore will it improve with the 20% stuff?
• If so, surely the extra cost of higher nitro content fuel is compensated for by reduced fuel consumption? So what fuel do you recommend for a novice?
• As I move over to 20% fuel next time will I need to make mixture adjustments and what tips can you offer?
• Would a "carb smart" be a worthwhile purchase to make this whole tuning process simpler for a lecky-convert like me? £30 plus a cheap servo doesn't seem like a big price to pay.
• I'm also considering some form of engine govenor - is there a product that combines this function with that of the carb smart?

Sorry for the shopping list of questions!

Si

[Steve]

Your low fuel consumption is because the engine is very rich since you're running it in. Rich = more fuel, Lean = less fuel.

If you ran two identical fully run-in engines on different nitro content fuels (say one on 15% and one on 30%) then the lower nitro machine would last longer. This is because with lower nitro content, you have to run the engine leaner to get the performance = less fuel.

[Si Goodchild]

I'm not sure how much running in the engine has had since the model was second hand although it looked pristine to me. How do I know when it's safe to start leaning off the fuel and would a "carb smart" help optimise this?

[Steve]

Carb Smart is just one more thing to go wrong and although I'm sure they are useful in the right hands and the right setup, it would be pretty pointless to a beginner. You're better off spending the money on more fuel, flying more and learning to tune the engine manually - there's really not much to it.

[moyesboy]

The raptor 50 tank is a bit small, as is the 600n tank.
I fitted a raptor 60 tank to my 50, I put a thread in here about it somehwere.
Its worth checking that there are no holes in the tank - its easy to damage the little lumps that stick out to locate the tank in the frame and then the fuel comes out of them when its running due to the exhaust pressure.
I remember being amazed how fast the fuel ran out in my 50 raptor when I was running the motor in!

[Si Goodchild]

I'll certainly check for leaks as there is some evidence of fuel on the underbelly of the helicopter and around the engine itself, bit it's hardly soaking and I'm not convinced that it would explain the rate of fuel usage I'm seeing. It's good to hear that a thirsty engine is not a new phenomena, but the next obvious question is how do I know when/if the engine is run-in so I can start leaning it up a bit?

[Steve]

Hard to say really, but my rule of thumb is approx 10 tanks along the lines of.....

1 flight just hovering - main needle 3 turns out, then
1 flight hovering again - main needle 2.5 turns out, then
1 flight gentle circuits - main needle 2 turns out, then
3 flight gentle stuff - main needle 1.75 turns out, then
5 flights good flying - main needle 1.5 turns out, then
fine tune the main needle to approx 1.5 to 1.25 turns out for an OS50 and engage the governor.

The number of turns out depends very much on the engine and no two engines will ever be the same, but the above is about right (from my experience anyway) for an OS50.

[Kwickkwack]

I fitted a new OS50 Hyper to a model last year, and during running in I was gobsmacked how much more fuel it used compared to my TT39 in my Rappy 30. however, now it is run in and I have leaned it off, I am now getting decent flight times without running very low on fuel. I have also noted that on my 50 1.25 turns out on the needle is normal (even in cold conditions) which i think contradicts the book that came with it, (1.75-2turns if I remember correctly). If anything I am sure I could go down to 1 turn out as it is still probably a little rich. but fine for what I do.

[robgt]

The MultiGov Pro has a built in "carbsmart" competitor.

Cheers,
Rob

[electricsceadu]

i would check to see if it has a raptor 30 tank in it
small tank = short flight times (and running rich will make it worse)

[Holst]

Its worth remembering that your fuel is also your engine lubricant, if you run too lean your engine wont be lubricated properly..this is especially important when your running the engine in.

I would run a few more tanks through with it running rich untill your confident its run in, and then gently lean it off as The Manager recomends.

It sounds like your running very rich at the moment, but thats no bad thing.

The leaner you run the more power you will have, and the less fuel you will use, just dont take it too far

[moyesboy]

It surely has a raptor 30/50 tank in it. They are the same part are they not?

[Heliblerk]

Hi Simon

I set your engine on the rich side of 'sweet' as it appears to be almost new, and as we don't know the running history this is the best initial setting. Now its had a few tanks through it we can start to lean it out.

My tanks last so long due to a combination of an old engine on its last legs that needs to be leanish to get any power, and a carbsmart in cold weather. I usually get about 11 mins in warmer wether conditions.

I should leave carbsmarts and govenors until later - just keep buying lots of fuel - the 10% stuff inwoods sold you is more than good enough. When the engine is tuned up you will get much longer runs

I'm hoping to be at the field on Saturday afternoon - see you then???

Andy