I hope someone could please help me, I bought a used nexus 30 and and a indoor hoverfly to train on, after some hover practice on the hoverfly I decided to take the nexus for a first take-off I fitted the training gear started her up and applied some throttle, I got about half way on the collective stick and i thought she was ready to take-off, I was just preparing to leave the ground and pushed up on the stick a little further at that point the the the engine throttled down and I didn't get off the ground. What I want to know is how could this happen is it somthing to do with the fuel air mix or could it be that the radio is not set up right or could it be that I just bought a duff helicopter. I hope someone can help as I've really enjoyed geting into this hobby so far but it would be nice to get of the ground!

There are a lot of factors that could cause it. Is the engine mixture set right? That would be my first guess is that it is way too lean, from the sounds of it. Did the engine get really hot? The next thing to check is the fuel getting to the carb. Were there a lot of bubbles in the line? How old is the fuel you are using? How much pitch do you have on the main blades at 3/4 stick and full stick? Is the glow plug bad? Is there something in the carb, has it been cleaned. Those are the things I would start with first. I would tie it down and get it running right before i tried to fly it. I used to do this for everything when I was starting, just to make sure it was set up and not vibrating and such. Start there and see what you find. Hope that helps some.

Thanks Flyboy, to change the mixture to make it rich do move the mix switch to the right and if i need to change the pitch how do I go about about this, the pitch does appear to be ok but I lose power just as im about to achieve take off speed, as for the glow plugs and fuel they are new, also I have a switch on my radio (idle up) that is flashing a mix warning can you explain this to me, I appoligise for my dumb questions but if I dont ask I wont learn,Thank again

In order to richen your mixture, you need to open the needle valve on the carb, this will allow more fuel to enter. What engine are you using??
If the engine bogs above half stick chances either your pitch or throttle curves are not set right. How much pitch are you getting at half stick?? Is there anyone in your area who flys heli's that could help you. Most of your problems probably can be corrected by someone who is experienced with heli setup.

I think my engine is a O/S 32 SX-H although im not 100% sure it has IRVINE written on it if thats any help, the fuel im using is model technics molecular blended glow fuel. By "how much pitch?" do you mean how much angle on the main rotor, I am getting pitch above half stick but the engine slows. Their are no clubs in my area nor do I know anyone that flies so I guess I'll learn by trial and error and any advice that will get me off the ground (literally) would be much appreciated. Thanks

Hi Rizla
See if your LHS has this book (Rays Authoritative Heli Manual)
It will help you understand the thing that are being said here.
It’s full of good info that will help you along with the help from
Good people here. It has help me out allot to understand the different setting to get my heli in the air.

hi i'm a beginner ,learned with eco piccollo,then progressed to collective pitch piccollo,now i'm flying caliber 30 glow engine,i've had about 1.5 gallons through of molecular blend,i am fortunate enough to have recently joined a club,and i'm doing quite well.The manager at the club helped me with my first flight ,ie.helped me trim the heli and adjusted the engine after first and subsequent flights,sorry to rattle on but i must advise you to not try flying glow helis on your own!!!even if you have no club locally,get a mate to accompany you,these things are very dangerous and you can't be too careful,also your bmfa insurance would be invalid if flying alone..as for your cut out probs,is your engine brand new??if so you should be running it at least 2 full turns out from the recommended adjustment on the carburettor thumb screw settings,a plume of smoke is an ideal indication of correct carb settings ,,hope this helps

"a plume of smoke is an ideal indication of correct carb set"

Not to be critical, but IMO that plume of smoke means very little. If there is very little smoke, you are running so lean that you might toast your engine, but you really have to go on sound, temperature (is the backplate so hot it sizzles spit?-bad), and how much power it has. It can still be lean and spitting alot of smoke because heli fuel has so much lubrication in it.

I've noticed that weather has a much greater impact on heli tuning than fixed wing, so I'm tuning much more that I ever thought I'd need to.

Could it just be the throttle curve is set incorrectly in your TX?

Rob

Thank you all for your help I just have one more dumb question if my mix is too lean do I turn the screw to the right/left? I was trying to sort it out this morning adjusting the screw a few clicks in both directions but did not notice any difrence in sound, what should I be listening for, the engine is not new and not running hot the previous owner has flown it about 5 times and it is 6 months old surely it should have some life in it still, hope you can help

turn anti clockwise(to left)to richen at mid and high revs using thumb screw adjuster,if needs richening at low(tickover)then turn the screw that requires a small screwdriver the same way but only an eighth of a turn on this one.hope this helps