RC India

Hello all,

Here is question am facing while thinking about Designing my own model concepts which are inspired by the current models we know,

THE POWER SYSTEM?

• 1) motor:kv2840 prop:6*4 battery:11.1V ESC:30A
  2) motor:kv2840 prop:5*5 battery:11.1V ESC:30A
  3) motor:kv2840 prop:8*4 battery:7.4V ESC:30A
  5) motor:kv1400 prop:9*5 battery:7.4V ESC:20A
  
• 
  

It is a sport model which needs good thrust for aerobatic abilities. The model weight is around 450g.

ideally a 1000KV motor 11*5-10*6 prop and 30A esc is suited for a aerobatic plane of 450 gms..will give a good torque on prop and nice and smooth aerobatics..! :salute:

i have designed a coroplast airframe weighing 450 grams all up. kindly suggest the power system and propulsive system for the same

You can go through this setup.   :hatsoff:
Motor:   1200KV/700gram thrust, Prop: 9x5 or 10x5
ESC  :    25 or 30Amps
Battery:  1300mah
Servo:    9gram.
I think these power system is sufficient to your aircraft.

@abhishekdas11,
Power required depends not only on the weight, but also on the wing loading and desired performance.
Pl post wing span and chord, and whether desired performance is like a glider/ slow trainer or advanced trainer or aerobatic.
You said AUW 450gms. Does this include motor, prop, ESC, battery and servos?

oh yeah wing span of 31inches and chord of 6 inches, required performance of a powered glider and its just the weight of airframe....exclusive of all electronics and ballast

and kindly help me out for selecting a prop...preferably a foldable one

Abhishek... With that wing loading I don't think you can get flying characteristics of a glider ideally for a glider the wing cube loading should be around 4 to 5 in your case it goes way beyond 10  so it's difficult to frame this model as a glider..I fee you will definitely have difficulty in keeping the model afloat...  Try to reduce the model weight...
And some pics would be helpful..

@abhishek11
Estimated weight of electronics in gms.
Battery 80, motor 60, prop 10, ESC 30, 3 servos 30, Rx 20, total 230gms
Bare airframe 450gms, hence AUW 680gms or say 23oz.
Wing area 31x6=186sqin or say 1.3sqft
Hence wing loading approx 17-18oz/sqft
At this loading it will be a bomb!

Examples:
1. My RCTLG
Span 48, avg chord 4, area 192sqin or 1.33sqft
Weight 200gms (6.9oz) with electronics
Wing loading 5.2oz/sqft
Flies slow enough to catch by hand on landing

2. Trainer for first time pilots
Span 54, chord 8, area 432 or 3sqft
Weight 600gms (21oz) with electronics
Wing loading 7oz/sqft
Flies slow enough for first time pilot, but can handle 20kmph wind

3. Glow 40 powered 60" Solo Star trainer
Weighs over 2.5kg, loading 21oz/sqft
Flies at 90-120kmph, lands at about 60!

SUGGESTIONS:
1. Build a slightly larger model, say 40x7, with depron weighing about 200-250gms without electronics

2. If you must build with coro, look at the built threads of sanjayrai55 (coromaster!), or in RCBolts threads

For your info, my electric trainer (no 2 above) uses a Turnigy Aerodrive D2830/11 1100kv, 9x5 prop, Zippy Compact 1000mah 3s battery and a very old Tower Pro ESC of 15amps rating. Typical flight duration 7-8 minutes with 11.4v left. Climbs at 45degrees on half throttle!
Many other motors suitable for a 40", 500g trainer, like EMax 2822 1200kv. Try to rpm per volt at 1200kv or less, so that you can use a prop of 8-9" dia.

Best of luck

is it possible to have a blended wing design...if yes then how to calculate the wing area

kindly have a look and temme whether design is fine or not

What's the material used and what's making it so heavy

It must be 4mm coro so its that heavy...

@topalle....wat i said ws a rough estimate....i removed an aluminium bulkhead at the LE wing to fuselage joint
now it has to be weighed again

else way i need to reconstruct the fuselage as it seems to b heavy....because i had glued on with fast-weld

@abhishekdas11
You are getting lots of inputs.
Just try to keep it simple, ok?

okay sir

iyer sir,
i have done a weight reduction and as of now it weighs 175 grams with increased span of 44". cud u suggest the powerplant-prop combination and the electrics as well

What is the wing area?
The stalling speed (below which it won't fly) is about 4-5 times the sqroot of the wing loading.
The cruise speed is about 2-3 times the stall speed.
Assuming 225 for payload and 175 for bare airframe, AUW will be around 400gms.
Need the wing area to estimate wing loading.
At this weight, a trainer can fly with 50Watts power, provided the wing loading is reasonable.

wing dimensions 44X5"

Ie, about1.5sqft
This will give you a loading of about 9oz/sqft. Not low enough, but not bad.
A motor of around 1000 watts should suffice
Do you have any motor already? Or Battery or ESC?
By the way, if you have a flat wing without dihedral, it won't be easy to fly.

Why don't you post details of what you have, and pics of your build?

no sir i dont have any motor or esc... i need to get all the stuffs dats y need exact ratings of the stuffs like battery power ratings number of cells . i have already shared pics of my build... tried to make diahedral  but cudnt succeed....

No. You have not posted pics of your new wing!
No dihedral means no inherent stability.
Hard for a new pilot.

I will stop here, as you are getting many inputs.
PM me if you need my help

tip dihedral may help.... It will increase wing area, also act as dihedral and increase stability

Also, as i noticed... you have the flutes of the coro sheet along the span...
They must be along the chord...

Why, sir?