RC India

RC Models => Electric Planes => Topic started by: Sreekumar VR on February 28, 2018, 09:08:43 AM



Title: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 09:08:43 AM
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 ?


Title: Re: Thrust to weight of an RC plane
Post by: 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.


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 10:46:41 AM
My model is builded with 2mm balsa and thermocol, it is in the building stage, not yet completed.. here is the picture


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 10:51:49 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


Title: Re: Thrust to weight of an RC plane
Post by: AL HAM SHARI on February 28, 2018, 12:06:04 PM
Nice plane btw,


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 12:50:45 PM
 :)tnx


Title: Re: Thrust to weight of an RC plane
Post by: Karthick Ashwath on February 28, 2018, 01:17:16 PM
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/ (http://www.rcindia.org/electric-power/iyer's-tech-talk-how-much-power/)
Hope it helps!


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 01:37:19 PM
 :salute:


Title: Re: Thrust to weight of an RC plane
Post by: Sumeet on February 28, 2018, 06:51:19 PM
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?  (:|~


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on February 28, 2018, 09:44:37 PM
Sure, I'll upload it soon.. Thank you


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 14, 2018, 07:21:15 PM
My newly designed Dream flier D16, finishing awaited..


Title: Re: Thrust to weight of an RC plane
Post by: AL HAM SHARI on March 14, 2018, 07:50:24 PM
Great


Title: Re: Thrust to weight of an RC plane
Post by: K K Iyer on March 14, 2018, 08:48:59 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.


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 16, 2018, 09:53:34 PM
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


Title: Re: Thrust to weight of an RC plane
Post by: sanjayrai55 on March 17, 2018, 08:17:22 AM
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


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 08:49:59 AM
@ 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.


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 08:58:24 AM
Here is the details,


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 09:02:25 AM
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.


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 09:06:07 AM
Wing dimensions..


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 09:11:44 AM
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?


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 09:26:56 AM
I used 2mm balsa used for fuselage, and wing frame, covered with paper coated thermocol sheet, (sanded).


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 09:30:40 AM
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.


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 09:38:21 AM
This is a miniature of piper arrow.. And I referred it's airfoil, given below


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 09:45:10 AM
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


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 09:55:58 AM
Ok, sir. Let me do a test flight with this model.. I hopes something good..  Do you think this model is OK??  ???


Title: Re: Thrust to weight of an RC plane
Post by: prabal276 on March 17, 2018, 09:59:38 AM
I'm no Sir!
The result of the Test flight is already predicted! If you do wish to try, make sure the CG is correct.
Please, that plane is beautiful. Keep it for later in my opinion.
If you don't want to keep it for later, take a bag along to the field. The reason being............. You know it! 😉


Title: Re: Thrust to weight of an RC plane
Post by: Sreekumar VR on March 17, 2018, 12:17:45 PM
I will accept ur opinion, anyway I'll do the test flight..   Thank you for your support..