RC India

RC Models => Electric Planes => Topic started by: gauravag on April 15, 2011, 10:09:38 PM



Title: Easystar issue - Too much downthrust
Post by: gauravag on April 15, 2011, 10:09:38 PM
Guys,
I was setting up a brand new EasyStar,  setup as below :
HXT 2835 (380S) 2200kv Brushless Inrunner
30 Amp ESC
2200mah 3S Lipo
2x HXT 900 9gm servos
TGS Sport 6x4E Precision propeller

Now, The CG was spot on, control surfaces trimmed out . But when i tossed the plane with motor at about 80-90%, the airplane just slammed to the ground. There seemed to be way to much downthrust.

The model was built with no modification to thrust angles whatsoever. The Brushless motor had fit in like a glove, so nothing had to be done, except to glue it in.

I did note that when i held the model in hand, and opened power, the plane wanted to pitch down.

Is there anything wrong I am doing ? Is this downthrust normal ? or do you guys remove that ?

See attached pics of the setup

Thanks all for your suggestions !
-GA


Title: Re: Easystar issue - Too much downthrust
Post by: gauravag on April 15, 2011, 10:14:21 PM
See attached for the amount of downthrust the stock setup has !!!


Title: Re: Easystar issue - Too much downthrust
Post by: SunLikeStar on April 15, 2011, 10:22:03 PM
Down thrust looks normal to me but 90% throttle is just too much. Try it with 40 ~ 60% max for launching. Once in air you'll have to correct the pitching tendency with elevator. It wont bother you once its in air.


Title: Re: Easystar issue - Too much downthrust
Post by: gauravag on April 15, 2011, 10:29:45 PM
ANother thing, Is this airplane launched by tossing it, with the nose up ?
I am used to launching gliders with nose level so thats what I had done with this, but it came down.



Title: Re: Easystar issue - Too much downthrust
Post by: SunLikeStar on April 15, 2011, 10:39:40 PM
Launch it level, but give it a good firm throw. After a few launches you'll get a hang of it and will be able to launch it even with a very gentle toss.


Title: Re: Easystar issue - Too much downthrust
Post by: akky on April 15, 2011, 10:46:07 PM
i have an idea..lets tow it up in the air using ur gasser  :giggle:


Title: Re: Easystar issue - Too much downthrust
Post by: gauravag on April 15, 2011, 10:48:19 PM
Launch it level, but give it a good firm throw. After a few launches you'll get a hang of it and will be able to launch it even with a very gentle toss.

Had done exactly that


Title: Re: Easystar issue - Too much downthrust
Post by: SunLikeStar on April 15, 2011, 10:53:34 PM
But you had too much throttle. Try it, i'm sure it will work out :thumbsup:


Title: Re: Easystar issue - Too much downthrust
Post by: foamybuilder on April 15, 2011, 11:01:36 PM
Check whether there is any downtrim in the elevator. If the trim is fine, adjust the trim for some uptrim and try again. If this works, there is issue with cg.
Try hand gliding without power first, to rule out any motor alignment issue.


Title: Re: Easystar issue - Too much downthrust
Post by: atul_pg on April 15, 2011, 11:14:44 PM
Hi Gaurav,

It was great to speak with you today :)

I don't thnk there is any problem, as sunlikestar mentioned try with the throttle at 50 to 60% am sure tat bird will fly neatly.

In btwn can you please tell me the diameter of the antenna again :D I forgot..

Foamybuilder - I dont knw if you knw, gaurav flies gassers  ;D

cheers


Title: Re: Easystar issue - Too much downthrust
Post by: vik on May 06, 2011, 04:38:19 PM
Hi im facing the same problem with my stock motor easystar,at full throttle it just wants to dive out of my hand into the ground,tried launching it at level and it goes about 10 feet max and nosedives.........any sugestions....


Title: Re: Easystar issue - Too much downthrust
Post by: rcpilotacro on May 06, 2011, 04:47:38 PM
it is not only down thrust, it could be your elevator position, before opening power have up elevator, as you open power when the air flow over the elevator energizes she will stop diving if there was even slight down elevator the problem will only accentuate


Title: Re: Easystar issue - Too much downthrust
Post by: vik on May 06, 2011, 04:55:20 PM
with little up elevator slould I launch at full throttle or 60-70 % power


Title: Re: Easystar issue - Too much downthrust
Post by: bokilap on May 06, 2011, 04:57:56 PM
I dont toss it myself (only did a couple of times). Usually someone else tosses it for me. But they toss it firmly with the nose travelling parallel to the ground. Before tossing, the throttle is usually at 50% and i am ready to give it a little up elevator as soon as it is tossed.

Mine glides perfectly without throttle but as soon as the throttle goes beyond 50% it shows tendancies to pitch down a little during flight. I usually give a little up elevator when i am increasing the throttle for levelled flight.



Title: Re: Easystar issue - Too much downthrust
Post by: vik on May 09, 2011, 05:37:23 PM
thanks for the input guys......finally did manage to get the easystar airborne at 60% throttle.....it flew straight but as I increased throttle to 100% it pulled right........tried to straighten it with rudder input but could not.......flew a few circles and crash landed............any guesses........


Title: Re: Easystar issue - Too much downthrust
Post by: gauravag on May 09, 2011, 10:18:52 PM
Do you have a brushless on it ? May need to increase the rudder surface.


Title: Re: Easystar issue - Too much downthrust
Post by: vik on May 09, 2011, 10:31:27 PM
No its a stock motor (premax 400)