Thrust to weight of an RC plane

Started by Sreekumar VR, February 28, 2018, 09:08:43 AM

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Sreekumar VR

Hi everyone, I'm new to this field. I'm building an RC plane. The motor I'm using is Avionic 1350kv. As per it's test results, it provides 790 gm pull when using 8x6 propeller. My model weights around 650gm. Can I have a perfect flite ?

kiran rc

What type of model are you building? For a typical trainer model the ratio of T/w can be low.
However, your setup has more than 1:1, so it should be good to go at half the throttle.Thrust to W ratio depends upon several factors, especially the Aerofoil/ wing design.

Sreekumar VR

My model is builded with 2mm balsa and thermocol, it is in the building stage, not yet completed.. here is the picture

Sreekumar VR

Quote from: kiran rc on February 28, 2018, 09:22:14 AM
What type of model are you building? For a typical trainer model the ratio of T/w can be low.
However, your setup has more than 1:1, so it should be good to go at half the throttle.Thrust to W ratio depends upon several factors, especially the Aerofoil/ wing design.

Thanks for the valuable information

AL HAM SHARI

A Dozen Scratch Built Models , 
VT-Speedster Pro
55' UAV Wing
Model  Rocketry

Sreekumar VR


Karthick Ashwath

For a trainer plane, the thrust ratio is definitely more than enough. ;D
If you want to know more about this, check out K K Iyer's Tech Talk.
http://www.rcindia.org/electric-power/iyer's-tech-talk-how-much-power/
Hope it helps!
Volantex Phoenix v2 2000mm
Lunchbox Chuck Glider (best flight 22s)
EaKa-1 WonderTube Trainer- Success!
Boat: DIY Catamaran Airboat

Sreekumar VR


Sumeet

Nice framework there in your plane buddy.  :)

I agree to the earlier comments. With your setup you shouldn't have any problems if it flies within a trainer portfolio.

Edit: Do you plan to post a build log of your build?  (:|~
<<<<<<<SUMEET>>>>>>>>

Sreekumar VR


Sreekumar VR

My newly designed Dream flier D16, finishing awaited..

AL HAM SHARI

A Dozen Scratch Built Models , 
VT-Speedster Pro
55' UAV Wing
Model  Rocketry

K K Iyer

Quote from: Sreekumar VR on March 14, 2018, 07:21:15 PM
My newly designed Dream flier D16, finishing awaited..

Don't add finish (ie, weight) now. Wait till after test flight.
Remember a golden rule: Simplify and add lightness!
Best of luck.

Sreekumar VR

#13
Now I'm little tensed, it weighs 750g now.. Everything fixed, motor thrust 790 g.. How my plane behaves in air,? TTW ratio 1.05. Please reply

sanjayrai55

Thrust thrust thrust!

Forget this obsession!

Look first at wing-loading & wing cube loading! Consider the type of model - glider, trainer, aerobatic, pattern, 3D, scale

That will tell you how your model will behave in the air. Accordingly decide your thrust/weight requirement

prabal276

@ Sreekumar VR
As Sanjay sir said, do not worry about the thrust
If that plane is built well, it will fly well.
Some of my smaller planes used to fly excellent with a T/W of 0.75
Fly it first
Do check the wing loading.
Please post your plane's dimensions and AUW weight.

Sreekumar VR

Here is the details,

prabal276

Well, looks like your plane will be a Hotshot. It will need atleast 60-75% throttle all the time. It will be fast. The wing loading is quite high for a trainer.

Sreekumar VR


prabal276

There you go:
The plane will fly fast and be quite aerobatic in nature. You'll have to fly it these are only predictions. Make a new one if you area beginner. Probably a FT Old Fogey.

What airfoil is it?

Sreekumar VR

I used 2mm balsa used for fuselage, and wing frame, covered with paper coated thermocol sheet, (sanded).

prabal276

I am asking about the Airfoil.
Please tell the Airfoil type.
You made it by hand but you may have used some shape for reference. I want to know that shape. I.e CLARK-Y,  NACA ¢¢¢¢ etc.

Sreekumar VR

This is a miniature of piper arrow.. And I referred it's airfoil, given below

prabal276

Well,
Looks like a symmetrical Airfoil.
That plane is a fully aerobatic sport plane. Will be very agile. With throttle, the speed will increase and to gain altitude, you will need to increase AoA. Completely opposite to a trainer.
It also looks as if you did not do the research before building the plane. If you would have, you wouldn't have put a symmetrical airfoil.
Can you make a bigger wing? With a flat bottom Airfoil perhaps?
Or build a tested beginner plane like the FT simple Cub or the FT old Fogey.
Keep the plane for later. Perhaps, when you are more experienced.
Regards

Sreekumar VR

Ok, sir. Let me do a test flight with this model.. I hopes something good..  Do you think this model is OK??  ???