RC India

I am a beginner and have not flown an rc plane but know about them a lot
 :help:
Ive finished building a 4ch rc plane.
plane specs.
length=800mm
wingspan=1200mm
weight=1200g
its a glider that i bought from a LHS and increased the width of the fuselage
the power setup is as follows:
ESC:Turnigy Plush 60A
Motor:NTM series 1800kv outrunner
Tx/Rx:HK T6a v2
Servos:Corona 939MG(x4)
Prop:8x4 APC
Battery:Turnigy 4s 1800 Mah 40c discharge lipo
CG= 25% down the wing
the first time when i tried to fly it I incresed the throttle to 50%,the plane picked up some speed. I pulled back on the elevator and the plane suddenly climbed up then i cut the throttle and it kinda crash landed but nothin happened.

Well heres the problem guys the second time when i tried to fly .i did the same thing gave 50% throttle gave some elevator and the plane climbed and left the ground by just a little bit ,then i decreased the amount of elevator then..... the plane rolled to the left and the prop hit the ground and thank god  :o only the prop broke.
now i dont know what to do ,please give me suggestions on how to take off and other things.
Thanks.

Noticed that your city location is bangalore. Where do you fly in bangalore? At Hoskote? Was it very windy and was the wind direction from right to left w.r.t the airframe?
I am asking specifically on the wind direction and it's speed as the roll effect may have been due to the wind. And since you are a newbie to flying you might not have been able to compensate off for the wind.
Plz confirm.

either try on simulator first...
or
fly ur plane under the guidance of experienced flyers..

actually i was flying at a big local ground. at the time of take off i took off against the wind itself but then as soon as the plane left the grnd i think there was a cross wind. and the wing is flat without dihedral  is that a problem

you must practice on simulator first
& one more thing pls increase throttle to full power & take off
as u said in the above lines
it seems to be underpower & made the plane to go for stall & crash

I would totally second aditya.
Download FMS which is a free software for flight simulator. First learn to fly without wind on the simulator. Once you are sure you can fly in the air, try practicing takeoff, take a quick turn and land. Again takeoff and land. Do this repetitively. This will enhance your landing skills. Now increase wind speed a few notches up. Takeoff, fly for some time, land. Once comfortable, increase wind speed and do the same. Do this till maximum wind speed. Then increase the probability of sudden change in wind direction, gusts, etc. Now change other parameters such as servos not responding, engine failure in mid-flight. Ofcourse, practically one cannot fly a plane in such extreme situations, but simulators do help to teach how to react when flight situations suddenly change and you want to save your aircraft.
Having said this, simulators cannot replace real world scenarios which are probably more varying and more worse. Few days back I had nasty easy star crash at hoskote. I had just taken off, and was doing a steady climb at 10-15% and attained a height of ~70ft when the easystar suddenly pointed to the ground and started losing altitude. Cut throttle, full elevator up but no avail. Thud. Started cursing my flying skills and thought, did i miss anything to learn on sim. Post crash analysis revealed the culprit, push rod failure. The force of the wind was too much for the stock push rod which got bent while i was giving a continuous slight up elevator to gain height.
Folks flying at hoskote are very helpful. Get in touch with them, bring your plane at hoskote. They will for sure be able to guide you.

Have you checked the CG of the wing? there is least probability, but it can also be the case..

the cg is about 25% down the wing
but 1 more doubt can u all hold up full throttle on ur brushless motor with prop on cause i cannot. i can maximum go upto 3/5th throttle and if i push it anymore further the motor stops for a moment and starts again???

Should i hand launch my plane or take off from ground , which is good for beginner ,and how

well, if you insist on not contacting local flyers for assistance, then yes anyone of the methods is acceptable. Personally I would prefer ground launch when doing alone.
BTW, the symptoms you defined in the first attempt seems to suggest that the bird is nose heavy. second the motor stopping may be related to increasing the throttle in a jerk (timing issue), so avoid

now should i switch the wing to a dihedral one or cont. with the same flat wing