Sceadu engine problem

[paddy]

Im running an OS 32 in a original sceadu and every now and then i get this problem where the engine doesnt have the power to take off but the pitch of the blades increases and you can hear it under extra load. Im tempted to think its to do with the mixture, i know its not the clutch as i have had that checked, is there anything esle it could be?
How many turns would you advise the mixture to be set at?
Regards
Paddy

ps first proper hover today!!!!!!!!! was also hovering at all points to the wind

I did the same thing but had the blades on upside down. Are yours?

TREV

[paddy]

by backwards you mean with the trailing edge going first?? if so mine definately arent backwards, cheers tho

Is the engine going the right way? With my cars if the engine goes backwards it sounds like that.

TREV

[paddy]

im pretty sure its not that, a guy at my local shop test flew it the other day and he would of noticed something like that.
Im beginning to think mixture because it started happening after i slightly altered the mixture, could it also be a dodgy plug?

[G-DAVE]

It could be the mixture - it' sounds rich .
The other thing to check is that the throttle arm is about 60% open at the hover point of the stick.
This is about the position needed for the motor to deliver enough power for hover.
O.S 32 normally runs best when about 1 turn open on the main needle if you have leaned the idle needle off this can effect the mid range.
When my motors are running well I've noticed the idle sounds a little on the rich side .
Dave D

If you take the blades and things off you can reach the engine running fast and adjust it I would not say to do it with the blades on because you may get hit. I think gdave is wrong though my mds throttle is 5 1/2 turns open so yours should be about the same, my cars have smaller engines which dont use as much petrol so there throttles are open less. And the bigger the engine the more petrol it uses so needs to be more open.

TREV

[paddy]

cheers for all your help guys, i think ive found the problem, its overheating a little, does this mean too rich or too lean? Or is there a better way to solve it? ive heard of the fans you can put on them to cool the engine, would it be a good idea to get one of them?
Regards
Paddy

You can get a little fan from computer stores which will run off a small battery if you put a switch in you can switch it on if the engine gets to hot then switch it off later this will save battery from running out.

TREV

[antsis]

Paddy

If it's overheating, could be lean. Is the engine smoking much? Not clued up on the sceadu, but you could also check the fan. If it's ever come loose, it could have hit the shroud and knocked some blades off.

My OS 32 is fairly new and I set the main needle at about 1 1/2 turns.

Ant

[Raptorite]

Hi Paddy,

If the engine is overheating it normally means it is too lean, in this case try richening it up a click or 2 at a time on the top needle until it starts coughing a little in the hover and then bring it back just enough to stop it coughing and give you good power. If you hear a sort of ticking noise coming from the engine it means that it is four stroking slightly and is still a bit too rich, when you get to this point make only small adjustments to the needle each time, usually 1 click at a time.

If you dont feel comfortable doing this get someone at the field to hover it for you as you may find that the tail kicks out a little when the engine coughs. Its nothing to worry about and not a problem with the tail, its just that the gyro will pick up and magnify any hesitation or roughness in the engine.

Once you are happy that the top needle is right, try doing whats known as a pinch test while the heli is ticking over. To do this, while holding the rotor head firmly with one hand, pinch the fuel line to the carb with your other hand.

What we are expecting here is for the engine to run on ticking over normally for about 3 seconds, it should then start to speed up before stopping completely. If when it starts speeding up you let go of the fuel line it should recover back to a normal tick over so you wont have to keep restarting it each time. For the final few tests it is worth letting it stop and restarting it just to be sure it is right.

If it starts to speed up straight away it means the idle needle is too lean, if on the other hand it carries on ticking over normally for longer than 3 seconds before speeding up, the idle needle is too rich. In either case make very small adjustments each time, retesting as you go.

When this is done, it shouldnt overheat.

I hope this helps.

Cheers,

Pete.

[paddy]

cheers pete will be doing the test you suggest 2moro

[Raptorite]

Hi Paddy,

No problems.

Let us know how you get on tomorrow.

Cheers,

Pete.