Noob Questions

[FLJim]

I've picked a basic 250 racer (maybe FPV at some point) for my first scratch build and started to order some parts (frame kit, motors/escs, FC, battery) so that I can start turning screws to feed my excited interest. However, I couldn't make myself rush on a few things and thought I'd start a thread here to see what answers the community could offer. Thank you for all the great posts and discussions...it has been very helpful and I hope that I can contribute as I start to build and figure things out! Here are my current questions:

1. Radio - I was tempted to by one of the cheap transmitters, but when I used to race cars and fly it was always worth it to get a quality radio. Also, I'm not clear on what the right number of channels would be. It seems like 6 should do the trick, but also have seen a lot of people talking about 9 and 10 channel radios. I want to invest in something that is going to last me for a few years and be usable for my first little quad and any others I build in the future. SO...how many channels should I have and has technology bridged the gap between inexpensive radios and the big names? Also, I like the idea of getting telemetry data (and battery levels, etc.).

UPDATE - Purchased the FrSky Taranis.

2. Battery Charger - Despite reading the LiPo thread and seeing other discussions, I'm still not comfortable with what a good first charger would be. I need something that will charge s3 (current batteries) and s4 (future) in the house and in the field. I don't want to spend a fortune, but can someone give me a brand/model that they use and recommend?

UPDATE - Purchased a Turnigy Accucel-6 50W 6A Balancer Charger and AC adapter.

3. GPS - What value does a GPS add to drone? Is it just positional data for seeing where your drone has been, does it allow for return to home based on location data, or something else? Maybe all of it? I'm thinking I don't need one for my 250 racer or general LOS flying...is that a safe assumption?

Finally, as a sanity check I think I'm starting to get some basics figured out and want to say it "out loud" around some experienced people. Let me know if I have this right...

FC - On the drone I have 4 motors. I need the flight controller to assist with balancing the output to the motors to maintain stable flight. Meaning the FC has gyros in it and detects any tilts the copter makes and compensates by increasing/decreasing output to the motors. It also takes signals from the receiver and based on its programming will manage the motors to respond. Such as increasing forward tilt to go forward or strafe and diagonal throttling to allow for spin. Finally, it might also contain programming to respond to "trick" commands such as flipping, etc.

Power distribution board - I've used brushless in the past, but only one. I believe in that case the battery plugged directly into the ESC. So because I have 4 ESCs which all pull high amps when loaded, I use the PDB to distribute the power from the battery directly to the ESCs/motors, it also allows for some circuitry to smooth the powers and also to provide other voltages for secondary equipment. The FC only signals the the ESCs directly and could get power from one of the ESC connectors.

I'm sure I will need to get some clarity on the FPV equipment once I start messing with that, but I'll save the brain power until needed...

Again, thanks for the help!

 

[John Doecliff]

Well I started with an 8 ch radio and found myself wanting more. My interest is in photography so I need gimbal and camera control. I just bought a Taranis which will do 16ch's. Its a $200 radio and comes highly recommended from many in the know. For the price you probably couldn't do much better. If you don't have a ton of cash to spend then I would possibly consider a Turnigy. A 6 ch will do but you probably should go with 8 if you can.

Chargers are rated in watts output. I don't remember what charger I have but as you upgrade to larger size batteries you need more capacity on your charger unless you want to wait forever to get them charged. You want to charge your batteries at one times (1X) their capacity, so a 1300mah batt should be charged at 1.3 amps. Not a problem until you get into larger sizes like a 5000mah batt that would need 5 amps. IxE= p so amps (I) times volts (E) = watts (P) so with my crappy math skills you would do well with one that puts out ~80 watts. That is if you never use a batt larger than 3S and 5000mah. upgrade to a 4S batt and as "E" goes up "I" goes down for the same amount of watts which means longer charge times. I'm at that point right now with a new build that will be using 6S batts. I need a new charger and power supply for the charger. It's turning out to be a somewhat large outlay of funds, not huge but not small either.

GPS on a 250 mini is not necessary at all IMO. If your flying LOS around your local park you don't need it. Build that 450 your talking about and its a nice addition for the reasons you gave.

A PDB keeps things organized and neat but it's not required. You could just make a wire harness. I built a mini 250 and I put a small PDB on it and I liked going that route. You do need to get a lower voltage to your radio receiver and FC and some PDB's have that provision built into them or use the BEC from the ESC. Don't forget to add a couple leads for power to things you may not be putting on right away like that FPV system or maybe some LED lights. Sucks to have to take everything apart to add extra leads.

 

[FLJim]

Thanks for the response John. I still have a long way to go to get everything figured out and will definitely take it one step at a time.

 

[Jonas104]

I was where you were out about a month ago. So I will probably speak in more layman terms than others haha.

John pretty much hit everything on the money. Also, you seem to have a good grasp on the purpose of the parts you will be purchasing, so that's good.

If you have a hobby store around, they are usually great places to go and get some great info on the spot. That's where I purchased my charger because on the internet, there are just so many options and methods of charging that I couldn't figure out what I needed. Try to find a shop that specializes in mulitrotors

I think FPV may be the easiest part, once your figure out how and why you're connecting all these components together, FPV will be a breeze. But like John said, you might want to think ahead and solder on some leads for other accessories. I think I pulled my quad apart about 10 times before I finished. It's a learning process, but so rewarding.

Pick this communities brains, I've always found answers here.

 

[Hoki]

I just ordered a 180 size one and it's so cute it sounds like a hummingbird.