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Slow Fly Build

Started by rahul_m_sharma, November 16, 2009, 01:23:27 PM

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rahul_m_sharma

I had completed my new SLOWFLY Build with
Model Name: SLOWFLY28
Plans from rcgroups.com
Wingspan 28"
Foam 6mm
4-5mm bamboo skewers for reinforcement of fuselage and wings
[Have spare carbon 2mm rod and 3mm hollow pipes for replacing bamboo skewer]
used cd cover cheap plastic for hinges
no landing gear

electonics
turnigy C1818 3500 kv micro brushless motor 12 gm
10A plush esc 9gm
460 mah rhino 20c
3xmicro servo 9gm each
castle creation micro stamp 9 gm rx
propellor is 7x4, 7x5,8x5,8x6,9x5,9x6

now problem is that i had fevicoled the bamboo skewer into wing and fuselage,
the weight is gone upto 200 gms with electronics,

I doubt this will hardly float forget about 3d.

please help me out with best combos
1> what shall be done to reduce the weight further? I am looking for indoor slow flying.
2> I hadnt tried maiden due to fear of breaking it.
3> is there any need to change my motor if yes what is the best motor available for this esc and battery for this plane?



Please advice.

rcforall

www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

rahul_m_sharma

I cannot open the link from my working desk can u mail me the price and specs of this motor.

rcforall

what is your  email id please
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

Ashta

#4
rahul,
Thank god you did not try this.
-for 200 grams you will need 50- 60 watts for a 3D.
-This motor can give only nax 30W that too at the max limit
- This motor can give only max 140 grams thrust.
- Those props are not OK for 3500 KV motor.   It will draw toomuch current and can blow your motr/ESC and the battery.
-For 3D you need a lower KV motor so that itcan spin a larger prop.
- You can use a blue wonder motor 1300KV and an 80X4.3 prop.
- The ESC/ Bat is ok. Is it 2 cell or 3 cell?
Making a plane light is also so much to do with what glue u use. Foam safe CA is the lightest but very heavy on cost. Hot melt is cheap but little heavy. The solution could be to scracely use hot melt. Also u can use 5grams servos.
For indoor flying u need a large hall.

Always it may be a good practice to check the current drawn on any new plane that you build.

ashta

You can't be first because you do not know!

rahul_m_sharma

Quote from: rcforall on November 16, 2009, 02:20:19 PM
what is your  email id please


rahul_m_sharma

#6
Yep, when I tried it without mounting on the bird it was unbarebely hot with all these prop combinations,
thank god I didnt pushed her too much. other wise I might had smoked my esc >:D,
1> I had use fevicol carpenter GLUE.
2> The battery is 2cell 7.4volt 20c Rhino
3> How to check the current drawn?


rahul_m_sharma

mean while I have 1700KV 24gms hxt brushless motor lying spare, can I put it with 25A mag esc and 460mah rhino 20c cells for this plane?  :headscratch:

Ashta

Quote from: rahul_m_sharma on November 16, 2009, 03:22:29 PM
Yep, when I tried it without mounting on the bird it was unbarebely hot with all these prop combinations,
thank god I didnt pushed her too much. other wise I might had smoked my esc >:D,
1> I had use fevicol carpenter GLUE.
2> The battery is 2cell 7.4volt 20c Rhino
3> How to check the current drawn?



Dear rahul,
To check the current,
pl see my post in this forum on low cost Volt- Amp meter. it is such a usefull (inevittable tool for electrics)
http://www.rcindia.org/servos-gyros-and-all-electronics/low-cost-diy-volt-amp-meter/

I am bit unpleasantly surprised that no body responded to such a usefull low cost tool for electrics, in this forum.

best regards
ashta
You can't be first because you do not know!

Ashta

#9
Quote from: rahul_m_sharma on November 17, 2009, 12:14:52 PM
mean while I have 1700KV 24gms hxt brushless motor lying spare, can I put it with 25A mag esc and 460mah rhino 20c cells for this plane?  :headscratch:

dear rahul,
1. As told earlier u need 50 -60 watts of power. this meand at 7 volts a current of 8- 9 amps.
2. Your battery  can support this in theory. But from my experience you can draw only a max of 6- 7 amps.
3. You can still use this battery motor combination provided you will not give full throttle only max 60-70%.
4.u can use 1700 KV motor with a 40X60 prop. check the current draw and ensure that it is not more than 6-7 Amps. depending on the current u can try different props.

good luck
ashta
You can't be first because you do not know!

rcforall

Quote from: rahul_m_sharma on November 17, 2009, 12:14:52 PM
mean while I have 1700KV 24gms hxt brushless motor lying spare, can I put it with 25A mag esc and 460mah rhino 20c cells for this plane?  :headscratch:

Rahul ,
To understand  the concept of the relation of the Prop to Motor you need  to go back to the basics for DC Motors :
The Basic Funda of DC Motors is the Torque is inversely proportional to speed .
Now the higher the KV ( RPM/V ) means higher speed hence going by the above  the ability of the motor spin larger props reduces as speed increases hence the higher the KV the smaller should be the prop.

Sai
www.zuppa.io : vehicle telematics, ADAS, IoT , Drones

mpsaju

Try this typical graph of the torque vs rpm of a BLDC motor (Brushless DC motor)

Happy Flying


Saju

rajathv8

Any update on this?
Astha sir, Will 18-20A ESC wt-18gms,  AX 2308N 1100kv brushless Micro Motor - 44gm,  ZIPPY Flightmax 1300mAh 3S1P 20C - 118 gms work well on this model?

Ashta

yes it should be OK. amy be 9X4.7 prop




Quote from: rajathv8 on November 11, 2010, 11:18:13 PM
Any update on this?
Astha sir, Will 18-20A ESC wt-18gms,  AX 2308N 1100kv brushless Micro Motor - 44gm,  ZIPPY Flightmax 1300mAh 3S1P 20C - 118 gms work well on this model?
You can't be first because you do not know!

hangingtough

Quote from: rajathv8 on November 11, 2010, 11:18:13 PM
Any update on this?
Astha sir, Will 18-20A ESC wt-18gms,  AX 2308N 1100kv brushless Micro Motor - 44gm,  ZIPPY Flightmax 1300mAh 3S1P 20C - 118 gms work well on this model?

i am attaching a few charts on 1100kv brushless motor thrust ,

This shows the thrust and amp at different props

I think you can live with 2S and still get about 400g of thrust on 7.8A, It will reduce your battery weight , hence slow flying


rajathv8