Century Falcon Engine Tuning

[flynnjo]

Hello

I am new to helicopters and want to know what are the best steps to take when trying to tune the engine of a helicopter. I have never done it before and do not know where to start. Anyhelp would be great.

[Aztek1701]

Hi there,

Welcome

The method of tuning heli engines depends greatly on the engine. I assume we are talking about glow engines here.. To my knowlege, best way to set up the engine is slightly rich. On your carburettor there will be one or more adjustments which correspond to different running speeds.

There are some signs that point to where you need to tune an engine.. when its flying if there is lots of smoke visible then its running too rich, if there is no smoke at all, then its running too lean. If it splutters or cuts out as the throttle is increase its probably too rich on the slow adjustment. If its hard to start, its probably too lean on the slow adjustment. You want some smoke from the exhaust just not so much that it looks like a civil war has broken out lol.

The consequences of wrong mixture are too rich... runs unevenly, drinks fuel, less power (especially under load), tendancy to cut out under load. If the mixture is too lean.. Engine cuts out. Back bearings damaged and worse. It only takes a few seconds of being too lean to wreck an engine.

The method I use is to set the engine up as per manufacturers instruction then richen the mixture about a half to a whole turn on the high speed adjustment. At this point I fly the model a bit and land and leave the engine running. I get over to the model quickly and get the blades stopped. Then I put my finger on the crankshaft backplate of the engine (the indented bit in line with the prop nut at the back) If I can keep my finger there for about 6-7 Seconds before I have to remove it because its hot, then its ok, if I cant keep my fingers on there as long as that, I richen the mixture on the fast adjustment a few clicks. If its cold, I lean the mixture out a few clicks. Im always cautious about over leaning the engine though.

The slow adjustments are harder to set because they affect the fast adjustments.. The way I understand it, the engine works by ADDING the jets together at a certain engine speed. If its too rich on the slow jet, it will cut out or splutter as the throttle is increased to the point where the fast jet comes in. Adjustments to the slow jet are done at idle speed and are critical in getting the engine to start correctly.

Thats my potted guide to basic engine tuning. Maybe one of our learned engine tuners such as seaking would be able to elaborate more..

Hope this helps.... Azzy

[hawkman]

It depends on the engine type as well, OS for example have a good manual that shows you where the settings should be as a baseline from which to tune if its needed.

I would place a filter on the fuel line for a start, a nicely tuned engine will not run well with even the tiniest bit of rubbish in the carb.

Theres lots of ideas about tuning, but its actually quite easy once you understand the basic idea like Aztek pointed out.

Rob

[flynnjo]

How do you adjust it with the blades running.....

[hawkman]

You dont.

The idea is to set the carb according to instructions, which might not exist with some engine manuals.

The low end needle...usually the smallest one...sometimes its located inside the throttle barrel/lever assy, is for the idle speed and influences the power right up to the hovering point/half throttle. The main needle also has its influence over the whole range of power though is more for half to maximum throttle.

Once the low end/idle needle is set then this shouldnt be touched as a rule...the main needle might need a click or two one way or the other.

Bear with me:

get the motor idling

pinch the fuel line and keep it pinched about 3 to 4 cms back from the carb.

Listen to the engine, if the revs rise straightaway then the mixture is too lean...so OPEN the low end needle a touch...try a bit of a turn.

If the idle starts to rise after 3 seconds then you are about right...any more than 3 seconds and you are too rich...so turn the needle down a touch....

Ok...go and hover about for a short while...land and touch the engine backplate...if its hot then you might have to adjust the main needle...too hot a backplate and you are too lean...so open the main needle a couple of clicks and try again.

Keep the heli low when hovering...head height is ok...maybe a bit lower. If the engine quits then the heli should settle down to earth slowly...just be careful with it.

What engine is it? please give details...the Toki can be a bit awkward to adjust from what I hear...some one here might know the settings...otherwise its a good motor.

Keep the pitch and power curves nice and Linear...ie follow the instructions with the Heli.

The thing is, engine power and mixture go hand in hand...too much pitch or too low a power setting at any given stick position will cause problems.

Once the heli is flying good, always check the skid under the muffler...if there is some oil there then thats good...just means the engine is getting lubed properly.

Keep the fuel nice and clean too...its not a bad idea to fit a filter between the muffler and the fuel tank too...just helps keep the dirt to a minimum.

I used to fly a Hawk, nice heli...now have a Predator gasser which is a nice machine.

Rob

[flynnjo]

The helicopter is a Centruy Falcon and it has a OS 46 motor....

[hawkman]

Right, well check the paperwork for the engine, OS do specifically say what the settings are.

Check them out.

Rob