RC India

Do a market survey for all the Electronics required for a RC Plane With Empty Structural Weight of 120g (without Electronics) and The Payload Fraction to be 0.75 with Gyroscopic Assist. Use a Suitable Thrust is to Weight Ratio.

i need to get inside of this problem and know all the calculations needed to solve this

Payload Fraction is the payload weight/ Total weight of plane.

For 0.75 payload fraction, with a 120 gram airframe (Assume 250 grams electronics weight) you will have to lift 1110 grams of payload. I Guess you had come to Manovegam competition today xD

0.75 payload fraction is not very easy to achieve. Considering the small size of the payload compartment, i would suggest reducing the aircraft size, or reducing your payload fraction predicted value.

thank you very much sir,,,  how to select brushless motor and esc for this design,,,  and how to add gyroscopic assist??

I'm not any sir :P.
I am just another participant like you.
Motor and ESC Selection is not a short procedure to explain. you have to consider the wing loading, then stall speed, then weight of the plane, Battery available. Using all that, you can narrow down to a few choices.
I have no experience in gyroscopic assist. and honestly, its not required.

 :)  okay ...  and what should my suitable thrust to weight ratio?  also can u guide me how to generate enough thrust to fly this plane?
thank you

0.8 should be fine, as long as your wing area is enough.

can u tell me where to refer for motor,propellor, esc selection to get ideas?

Maybe hobbyking? It gives a wide scope.

my total weight of rc plane is 1480 grams,,,  what should be my wing loading???

i dont know how to get suitable wing area when i only know the  weight of aircraft,, in my case weight of aircraft =1480 grams...  so how to calculate wing area when only weight of aircraft is known??

Go for 16oz/sq.ft. wing loading. Using this your wing area should be:
3.25sq.ft.But only if you are a beginner. If you are an advanced flyer, you could go for 18-20 oz/sq.ft

I read an article on flitetest sometime back where someone made a really huge rc plane in under 300gms. I am not able to send the link since I am on a very slow connection right now. I will post it asap. That design can help you achieve a really low wing loading.

Please share the link nitesh!

Ugghhhhhh I am not able to find the article right now.

BTW Karthick how is your solar plane project going on?

Please check my thread some new updates are there

I once read a comment by a coach of American SAE Aero teams.
He said
"Most of the models had never been flown before"
And that was the biggest reason for failure.

I don't know your flying or building experience. If you are an experienced builder/flyer please excuse me for my suggestions that are intended for beginners.

1. Learn to fly RC first, before tackling payload problems
2. Build a proven design, and see how much extra payload it can lift safely

You may find that a 0.75 payload factor, which means payload 3 times the weight of the ready to fly airplane is  almost impossible

So my suggestion is to buy/borrow something like a Skysurfer, learn to fly it reliably, then add ballast.
Will give you an idea of just how much payload a reliable model can carry.

If you already have a model that you are flying regularly, just add payload!
Best wishes.