hi guys,
I want to make RC Plane According to these parameters:

max battery weight : 120 gm
max diameter  of propeller : 10 inch
T/W ratio = 0.75

...
so for start manufacturing  i need to know max weight of RC plane.


So Anyone can say ,

According to battery weight i can use which battery and which brushless motor ... and i will get howmuch thrust by using 10 inch propeller on that motor? 

..
please help....

On what basis have you selected battery weight and propeller size?

Sent from my Moto G (4) using Tapatalk

Specify the type of plane.
The criteria is simply odd.

Hey Shyam,

I assume that you are using, a 3S battery and 10in prop

so you can use 1000kv motor which is radially available and very cheap

If you search on youtube "2212 1000kv motor thrust" you will see some demonstrations where the 1045 prop and 1000kv motor combo with 3S battery has given approximately 800grams of thrust.

and you want 0.75 thrust to weight ratio

So the weight of the plane can be max 1066.66 grams. (1066.66 X 0.75 = 800grams)

Hope this helps.

i have not selected .
i am going to take part in competition,so these are the parameters given by competition organizers .

Quote from: S_H_Y_A_M on July 25, 2017, 07:14:45 PM
I want to make RC Plane According to these parameters:

max battery weight : 120 gm, max diameter  of propeller : 10 inch, T/W ratio = 0.75

i need to know max weight of RC plane.
According to battery weight i can use which battery and which brushless motor ... and i will get howmuch thrust by using 10 inch propeller on that motor?  

These three parameters don't mean much unless the flight objective is stated.

But let us see what these 3 parameters can lead to:
1. Battery weight 120gms. My Zippo 3s 1000mah 25c lipos weigh about 90gms.
2. A DT700 using a 3s lipo will produce 750gms thrust with an APC 10x3.8 (ref Mortimer on RC Groups), drawing 10 amps
3. Using 2 such will give 1500gms thrust drawing 10+10 amps
4. Drawing 20amps from the 1000mah lipo will give 1 minute duration without draining even 50% capacity
5. Your model can weigh upto 2kg for a 0.75 thrust/weight ratio

This is only one example  

Edit: Statement #5 above is incorrect
Pl see reply #7 for correction

Quote from: K K Iyer on July 27, 2017, 10:11:05 PM

Quote from: S_H_Y_A_M on July 25, 2017, 07:14:45 PM
I want to make RC Plane According to these parameters:

max battery weight : 120 gm, max diameter  of propeller : 10 inch, T/W ratio = 0.75

i need to know max weight of RC plane.
According to battery weight i can use which battery and which brushless motor ... and i will get howmuch thrust by using 10 inch propeller on that motor? 

These three parameters don't mean much unless the flight objective is stated.

But let us see what these 3 parameters can lead to:
1. Battery weight 120gms. My Zippo 3s 1000mah 25c lipos weigh about 90gms.
2. A DT700 using a 3s lipo will produce 750gms thrust with an APC 10x3.8 (ref Mortimer on RC Groups), drawing 10 amps
3. Using 2 such will give 1500gms thrust drawing 10+10 amps
4. Drawing 20amps from the 1000mah lipo will give 1 minute duration without draining even 50% capacity
5. Your model can weigh upto 2kg for a 0.75 thrust/weight ratio

This is only one example   

Thank you Iyer Sir.

Statement in reply #5
5. Your model can weigh upto 2kg for a 0.75 thrust/weight ratio

Since 0.75 thrust/weight ratio is presumably the max stipulated, point #5 should read:

"Your model must weigh at least 2kg to be within 0.75 t/w ratio"

Another example that can meet these parameters:

http://www.rcindia.org/electric-planes/smallest-rc-plane/msg274146/#msg274146

I think you intend to participate in Boeing IIT National Aeromodelling Competition.

It has two rounds,

Round 1: Maximize Gliding Time
The model has to be hand launched and throttle can be used for 20 seconds. after that, throttle has to be cut off and the model has to glide for maximized. This is an elimination round, where some teams will be eliminated
You get 5,000 Rupees if you qualify this round.

Round 2: Passing Through Gates and Dropping a weight
The Model has to pass through Two or three gates in the specified manner, and drop a small weight of 50 grams in a circle.

I know this because i had participated in Boeing Aeromodelling Competition in IIT Madras last year

This is the competition requirement.

The thing is if you intend to go to IIT Bombay,
The competition page is last year's. Even though the website is updated.
So please hold on.

Quote from: K K Iyer on July 27, 2017, 10:11:05 PM
These three parameters don't mean much unless the flight objective is stated.

@s_h_y_a_m
As you would have realised from my earlier posts, the parameters mentioned by you can be satisfied by a model of over 2kg, as well as by one less than 2gms, as the flight objective is not stated.

Let us know the flight objectives, as and when finalised, so that we can try to give you some useful inputs.
Regards.