problem lifting off

Hi all,having a problem taking off ground,when my heli is about to
take off at half throttle she looses power,there is alot of smoke as well,should i change the pitch to a higher angle or is the mixture to lean or rich,the pitch is set at around 7 degrees for hovering.

[kramer]

Sounds like a mixture problem,you should be about 1 1/2 to 2 turns on the main needle

[Seaking]

Sounds like a mixture problem,you should be about 1 1/2 to 2 turns on the main needle

I find it amazing that you can say what position his main needle should be
when you don't know what engine he is using

FYI there are engines out there where it is the Low end needle that actually control the fuel until the 3/4 stick mark


Sean
We need a bit more info than you have given us
What engine ?? How old is the engine ?? What exhaust??
What fuel?? What Heli.. Etc etc

It does however sound like a fuel Mixture/flow Problem

Roger

[kramer]

I may be new to this forum but I am not new to engines or helis .If you read his post you would have noticed that he was @ 172 throttle position wich is 80%+ on engine throttle far above the low/mid range adjustment and he also mentioned a lot of smoke whitch is common with a very ritch high needle.If he was having an idle or transition problem then the low/mid setting might be the problem.I just got done setting up a new heli and had my high screw way too rich(forgot to check it) and had the same simptoms as described above! 90% of all my engines fall in the needle range of 1 1/2 to 2 turns ,heli and plank,it is just a base setting and every engine is differant,I have a few that are less than 1 turn and a few that are more than 1 1/2

[Seaking]

@ 172 throttle position which is 80%+ on engine throttle far above the low/mid range adjustment

Could you please explain that to me

HE stated he was at Mid stick with 7 degrees of Pitch which on a helicopter is too much Pitch for midstick AS most helis only need a max of 6 degrees to maintain a steady hover Depending on type of blades of course and a well matched throttle to Pitch curve

As well as having a mixture Problem he also by the sounds of it has a throttle and pitch Curve problem

Mid stick could indicate anything especially if using a computer Tx
Do you know what Throttle curves he has set ????? no and neither do I
Hell he may even be using a governor

For instance he could have set the heli mechanically for a Pitch range of -4 to +11 and adjusted his Tx curve to get a 7 degree Pitch at mid stick

Or he could have set his Pitch Range -9 to +9 and used his Tx curve to again set 7 degree at Mid stick
Again do you know what he has got set????

Assumption has cost quite a few folks a lot in crash damage LOL

A very popular engine for Helicopters is the Thunder Tiger Range
And if you go less than 3 -4 turn out you could lean out the engine and damage it ..
Do a search on RunRyder and you will see that a lot of folks start with it 5 turn out

Or the Webra which doesn't like high nitro and may need to be shimmed

I have no doubt that its probably running too rich but until we know the Helicopter, engine and curves that he is using We cannot say adjust this needle to this position
Been there done that and I've got the damaged engines to prove it

What makes you think That I am any less experienced than you
FWIW I started flying Planes some 22 years ago and Helis in 92 Gave them up due to work commitments and started again 3 years ago I now have 2 Planes and 6 helis All on Glow except for My Predator Gasser and all use different Engines and as Such all get tuned differently
I use Pitch and throttle curves on everything bar 1 heli which has a CSM Revlock fitted on it and that is my "experimental " heli
The only helis that i do not have any experience with are Electric/Turbine and as I have no intention of using them I leave them well enough alone

Now if I have some how managed to upset you then I apologise as that was not my intention
My intention was purely to point out until you know his set up you cannot say adjust anything to this position

Roger

Originally Posted by sean naughton

Hi all,having a problem taking off ground,when my heli is about to
take off at half throttle she looses power,there is alot of smoke as well,should i change the pitch to a higher angle or is the mixture to lean or rich,the pitch is set at around 7 degrees for hovering.

I would reduce the pitch a fraction perhaps six degrees, is the engine well run in? What engine do you have? I run my sceadu 37 at about a turn and a quarter on the big needle, running nitro 30. You have to richen the mixture a little for high nitro content.

It sounds like you are running too rich, lot of smoke (means a lot of oil is going through the engine) followed by loss of power would indicate to me that you are flooding the engine at that point. In suspect you are running nitro 15 so I would start at a turn and a half and then crank in a couple of clicks a time (anti clockwise) to lean off the mixture. Then try taking to hover each time and see how it behaves.

[hawkman]

I would love a Predator gasser......one day...one day;-)

Assuming things can cause no end of problems.....theres loads of experts on engines...all have differing ways of tuning..heres my advice....for what its worth:

Check your pitch range and throttle range.....at mid stick the pitch should be around the +5-6 degrees mark....if you are a learner then the bottom of the stick would need something like 0 degrees.....the top end of the stick might need +8 to +9 degrees.

Your throttle curve may need adjusting....but mid stick should be %50 but bear in mind that engines are not exactly 'linear' in their power delivery....you may well need to adjust the settings to get a good power delivery....the idea is to get a constant head speed...or near enough...so as you adjust the collective pitch the headspeed stays more or less the same as the blade load varies through its pitch range.

Its really only then that you can start to mess around with the carb settings.

Check your heli manual for the pitch setup...make sure its the 'normal mode' on the idle up....inhibit the rest...if you are learning then you dont need to worry about inverted flight and all that.

Check your engine manual for the carb settings.....OS engines have a good manual with them.....other engine makes are very shoddy when it comes to printed instructions.

There should be some smoke....but you must tell us what you are flying...I guess its a Hirobo something or other.....what engine is it?.....is it a new engine? what fuel are you using?

Do tell us....there is a wealth of experience here....for you to gain from....we all learn off each other....no one knows everything.....least of all some goon like me;-)

Rob