problem on payload fraction

[yash12]

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

[topalle]

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.

[yash12]

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

[topalle]

I'm not any sir .
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.

[yash12]

   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

[topalle]

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

[yash12]

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

[Karthick Ashwath]

Maybe hobbyking? It gives a wide scope.

[yash12]

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

[yash12]

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??

[Karthick Ashwath]

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

[rcrcnitesh]

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.

[Karthick Ashwath]

Please share the link nitesh!

[rcrcnitesh]

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

BTW Karthick how is your solar plane project going on?

[Karthick Ashwath]

Please check my thread some new updates are there

[K K Iyer]

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

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.