Planning first quad build [must get right the first time]

T

TheSentinel

Member
I have never built a quad before, never seen one in person, nor touched let alone fly one. I have to make sure that I know all the considerations; and that after ordering all the materials, the only thing I'd need is to tinker to get it right (because of limited time and long shipping time).

So please review the materials I plan to use then answer some queries I have or maybe point out some mistakes or considerations I haven't made but should have.

Current list of materials:

SK450 Quadcopter Frame: http://bit.ly/1HETass
  • 300g
  • 450mm width
SK450 Quadcopter Frame Extended Landing Skid Set: http://bit.ly/1o0SBhJ
  • 39g
935kV Brushless Motor and 10x4.5 Props (4): http://bit.ly/1GXd8bf
  • 55gx4=220g
  • 15A max current draw for 10s
Afro ESC (4): http://bit.ly/1M0MPnv
  • 22.8gx4=91.2g
  • 20A
  • afro_nfet.hex firmware
ZIPPY Flightmax 5000mAh 3S1P 20C (2): http://bit.ly/1ToqcPH
  • 404g*2=808g
Raspberry Pi 2 Model B: http://bit.ly/1GZuchP
  • 45g
10DOF IMU: http://bit.ly/1RjkCAh
  • 2.8g
  • Usual 9 axis + Altimeter + Thermometer
GPS Module: http://bit.ly/1JVI8Q8
  • 8.5g
Camera: http://bit.ly/1ghz37l
  • 3g
RF Transceiver 900MHz Band: http://bit.ly/1HewJaa
  • 1.5g
Cloverleaf Antenna 900MHz: http://bit.ly/1UAtCQP
  • 72g
Transceiver Dongle 915MHz: http://bit.ly/1eK4Dtw

Total quad weight: 1.59kg

Other items:
Hobbyking B6 AC/DC Charger 5A: http://bit.ly/1J6EQ6I
-Couldn't find a 10A charger in HK, too bad.
LiPo Charge Bag: http://bit.ly/1G13zHn
Afro ESC USB Programming Tool: http://bit.ly/1JTFw27

Not listed:
LVR
Speakers

Questions:
  1. Does my quadcopter have decent thrust, flight velocity for its weight, motors, props?
  2. Does it have the proper power system? Planning to have two LiPo cells for a grand total of 10Ah, a really long flight time is desirable.
  3. What connectors am I missing?
  4. Raspberry Pi 2 is going to function as the flight control and pretty much any type of data processing, do I have components here that wouldn't interface with RPI very well or not at all? Will RPI2 be able to handle all of this?
  5. I heard speakers can cause the flight navigation to mess up, should I be worried to the point that I must remove them? The speakers would be at around 40~80W.
  6. I don't think I could find an easy programmable remote control for this, so I did away with it. I plan to use the transceivers and antennas to replace the remote, basically a laptop would serve as the remote controller. Also, I plan to broadcast the video the same way. Is this set up fine, given enough programming?
  7. Should I worry about heat dissipation? Add heat sinks? Etc.
  8. Am I missing accessories that I really need?
  9. Quad is planned to have destination coordinates periodically transmitted to it from base station, as well as semi-real time broadcast its location to the base station.
Thank you in advance to anyone who can give me input.
 
H

HDtallrider

Well-Known Member
Hi Sentinel! Welcome to the Quad World:D. I am not sure what kind of use you are planning for your quad. The speakers, amplifier (?) and giant battery packs are more weight than a 450 can handle. Sounds to me like you should be looking to build a 700 to 900 size quad. How about posting some more specific details on the type of performance you think you'll need? For example; if you are going to spend most of your flight time hovering or making gentle turns while taking video that would be a different power system and flight controller than one that would be doing quick, high speed turns and altitude changes. Also, give a hint at your budget. Beware of the cheap stuff! Explain why you don't want to use a Tx and Rx. Why are you going with 900Mhz? Why not PixHawk? easily programmed. A Wii based system is another option if you feel you have to use a laptop. The more specific the info you give, the more solid info you'll get back. There are a whole bunch of real knowledgeable people on this forum that would just love to help you spend your money!!!:p Remember....it's not just a hobby. It's a disease! LOL
 
Herpderpwerp

Herpderpwerp

Well-Known Member
Yup, i think a 450 is too small for the kind of stuff you will put into it, for a 1,6kg body, you'll gonna need at least 3,5kg of thrust. I don't think the motors will provide that much thrust.
How much flight time did you expect?
If you want to put that much stuff, at least you'll need a 600 or 700 frame, with low spinning motors, maybe at a 350 or 450kv motors with 17" prop size
 
GJH105775

GJH105775

Off and on
Moderator
Let us start from the beginning. What are you designing it to do. Approximately how much do you plan to lift?
 
T

TheSentinel

Member
Well this is meant to be a project for school. It's supposed to be some sort of semi autonomous drone that would be used post calamity or something like that. Sort of an emergency response. Like officials could announce to or guide people through the speakers etc. It doesn't have to be that fast. It's not going to do tricks or whatever. More of a gentle glide I guess. As long as it would get there in a decent amount of time. Budget would be at minimum possible. Though the sophistication required heavily opposes that. 900MHz because of it's range, also because it's the lowest frequency legal in the country. And it's less populated, meaning less interference. No controller because I'd want to reprogram everything from scratch anyway. And besides, I don't plan to go manual as much as possible. A single transceiver that carries the video and controls and pretty much any data is what I'm aiming for. So I plan to do only laptop to quad and vice versa. I have to reprogram the flight controls from scratch too.

I've heard most flight times are around 8 minutes or so. If I could extend to about 30 minutes that would be great. Are 17 inch props available at HK? I'd have to check first.

How much do I plan to lift? Quad itself, hopefully less than 2kg. Besides the quad, no plans yet. Maybe just a first aid kit or a flashlight or something to be dropped off. But only if the carrying capacity allows it. Otherwise, I wouldn't bother carrying anything else.

Anyway, frame size and type was picked because my teammates liked the way it looked. For me I thought as long as it fit it'd be fine. So I guess ignorance is the reason.

Also, navigation is pretty simple. No obstruction based flight navigation. Just fly up to a good height, fly to destination, descend, then do some actions. Like patrolling or hovering by itself. Maybe act as speakers on site, or take pictures. Ascend, then fly home. Something like that.
 
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Herpderpwerp

Herpderpwerp

Well-Known Member
Hmm, the biggest problem would be your flight time, if the quad will carry so much payload, maybe you should consider a hexa, it has better stability an bigger payload because there are 6 motors lifting it up, if i'm not wrong, low Kv motors with big props will give you bigger payload and longger flight time, at the cost of agility. The part with the laptop as your transmitter, i can't comment to that because i have no knowledge at all about the matters heheheh
 
T

TheSentinel

Member
Going for a hexa seems daunting. I'm sort of afraid of the flight control system involved with 6 motors. Lol. I've only recently just brushed up on quad aerodynamics. Still in the process of learning it.
 
Herpderpwerp

Herpderpwerp

Well-Known Member
Then in my opinion, you shoul try low kv motors with big props, but try to find the motor that are in 20-30amp range, it should have enough thrust and not pulling the battery so much
 
T

TheSentinel

Member
Also, besides the speakers. I've only added a second battery. Why is my quad so heavy? The electronics are pretty light, right?

I don't think I've read this anywhere. But having two batteries in parallel is simply all I have to do to use 2 of the same kind of batteries, right?
 
Herpderpwerp

Herpderpwerp

Well-Known Member
Power distribution board can simplify the wiring, it is very useful in smaller frame because there is so little room left for wire, but in large frame it is not so important because there is plenty of room for the wire. The battery take almost 50% of the weight. Double the battery doesn't mean double the flight time
 
T

TheSentinel

Member
But it makes it just a bit less than half longer right? Or does having two batteries at that weight actually make it worse because I'd need to have a different set up altogether which draws more power?
 
Herpderpwerp

Herpderpwerp

Well-Known Member
The battry you use is 5000mah 20c, so if you have 2 batteries in pararel that means you have 10000mah at 20c. It equals 200amps. Now you must calculate how many amps the motors draw at max thrust and at hover, also calculate the efficiency of the motors.
Go to http://www.ecalc.ch/xcoptercalc.php for simpler method heheh
 
T

TheSentinel

Member
I'll do the calculator later, am on mobile. Anyway, I'll try to propose a new set up later. I found a 5200 mAh LiPo 10C cell which is also lighter, about 330g. 104A seems decent. I'll try coupling two then use a larger frame with a whole new set of accessories as well as use lower rpm motors with higher max current draw capacity and much larger props.
 
T

TheSentinel

Member
Yeah I was just curious about that. LiPos seemed like special batteries so I'm afraid it doesn't act like regular batteries. Are there cables for power distribution that split into 5? I heard soldering big wires were a pain. It also makes it cleaner. Bad soldering joints might burn up at currents like that I'm afraid.
 
GJH105775

GJH105775

Off and on
Moderator
TheSentinel said:
I'll do the calculator later, am on mobile. Anyway, I'll try to propose a new set up later. I found a 5200 mAh LiPo 10C cell which is also lighter, about 330g. 104A seems decent. I'll try coupling two then use a larger frame with a whole new set of accessories as well as use lower rpm motors with higher max current draw capacity and much larger props.
Click to expand...

Sounds like the 5200 mutistar I have it and can say that is is great and lighter than most 3 Ah batteries.
 
H

HDtallrider

Well-Known Member
I'm not sure you can use HK exclusively and achieve your goals of lift and efficiency. The MN3508 380kv T-Motor using T-Motor 20a, 600hz ESC's (no programming needed ) and swinging a RCTimer 16x5 CF prop can lift 4800g and is the 2nd most efficient motor out there ( the 1st is a budget breaker ). Combine that with a Multistar 4s 10c 10000Mah battery (very light) and 45 minute + flight times are possible. Food for thought.....
 
T

TheSentinel

Member
The MN3508 set you say seems very promising. But the price of the motors itself is burning a hole through my pocket already as it is. Ha ha. We'll try to stay under 1500g. Is it still not possible to use a 450 frame? I got a set up with ecalc. 3x5000mAh 10C batteries with about 850kV motor with 250W max power draw and 10x4.7 props. It has a measly 15min flight time but decent flight velocity. If only ecalc let me input custom variables and/or had a wider selection to choose from.
 
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