Hii Everyone,
   I'm trying to fly rc electric airplane made using banana wood of weight approx 540 gms.(including all items like motor , Li-PO battery etc). But haven't succesfully flown it  ,i think there is lack of rpm given by motor , so i'm now thinking to buy a new one for better experience. Please advice me for other options.

Items spefication as follows:

***Outrunner Brushless Motor 1038KV | 8 Turns | 1.1A Running-Light Current | 8-12 cell Ni-MH/Cd Battery | 3-4 cell LiPo Battery | 25A Max     Permissible Current | < 20A Running current | 68g Weight | Ø4mm Shaft | 1.2 kg Max Pull | < 10x7 Propeller

***ESC25A Speed Control for Brushless Motor, 25A

***Li-Po Battery 1000mAh 7.4v (7.4Wh) 2S | cont 20C/ Burst 40 C

***8x6" propeller

Also please give some tips on how to take off a rc electric airplane.

Thank You

Welcome to RCIndia !

successful Flying of rc aeroplane generally depends Flying skills of pilot, structure of aeroplane and power system you are using.

So first ensure that you are capable of flying plane. Have you flown any RC  plane before? Have you practiced enough on simulator to be able to fly rc plane in real? in not then first try to practice on simulator.

Most importantly spend some time reading threads in http://www.rcindia.org/rc-india-forum/the-rc-india-gems/
and ensure that your plane is structurally stable to be able to fly. Then check your power supply.

Also if possible post some pics of your plane so that people here can suggest you solution if there is something lacking in your plane.

+1 Spitfire.

Quote from: spitfire on January 15, 2012, 12:46:44 AM
So first ensure that you are capable of flying plane. Have you flown any RC  plane before? Have you practiced enough on simulator to be able to fly rc plane in real? in not then first try to practice on simulator.

Thanks For Reply !!
I had never flown any rc airplane before , i had made it out this one from wooden parts kit. I had practiced enough on simulators. but as you know very well real life experience of the same is very very much different from simulation....

I had asked should i replace the motor with another to resolve this problem.....

Quote from: Sumeet on January 15, 2012, 12:50:02 AM
+1 Spitfire.

I think GOOGLE+ (https://plus.google.com/) is a better place for you to do +1 ...

As per configuration of motor, it seems good for such auw.
If you feel rpm is less then try using 3 cell lipo. Using 3 cell lipo will increase rpm of motor. You can also try using bigger prop.

Quote from: spitfire on January 15, 2012, 01:34:19 AM
As per configuration of motor, it seems good for such auw.
If you feel rpm is less then try using 3 cell lipo. Using 3 cell lipo will increase rpm of motor. You can also try using bigger prop.

Thank You spitfire
i don't have any 3 cell lipo, rather have two lipo batteries of the same config ,
is there any way to use both lipo???

Technically you can use two 2cell lipo in series that will give you voltage equivalent to 4 cell but practically it is better to use single battery as there is always some difference between capacities for two batteries.

If you are using batteries in series then make sure that your motor can handle 4 cell, capacities and mAh rating of both lipo are same and current drawn by motor is under specification of ESC and lipo.

Testing with watt-meter before flying is a good option to ensure current draw by motor.

Spitfire

That is a superb answer,

With 10x7 prop you getting 1.2kg pull (with 3S Lipo).
So your maximum current setup pull = 1.2 kg x  (TT x 8 x 8 x 6 x 2)/(TT x 10 x 10 x 7 x 3)
= 0.438 kg.
Now look why this ?
with one rotation of 10x7 prop shifts volume of Air = TT x D x D X P / 4 Cu Inch
where TT = 3.141,  D= Dia of prop, P = pitch
And so, replacing prop, you can get corresponding ration of Air shift.
Moreover, If you use low cell voltage, RPM also reduce with ratio of Voltage.
Thats why your effective pull reduce.

Now when you are using Motor with capacity 25A (Max), you should use at least 1.5 x 25A ESC and not below 30A.

So, it may be your ESC shuts down for overheating in fail safe mode and lands.

Please just replace the prop and check. Also, you need to replace ESC Later, but just try with prop replacement. Hope it will works. And better use Slow flyer prop.

Thanks.

Quote from: augustinev on January 15, 2012, 06:22:25 AM
Spitfire

That is a superb answer,

Thanks for appreciation Sir