Replies to This Discussion

Permalink Reply by Vernon Barry on April 6, 2012 at 6:17am

There have beena lot of discussions here about heavy lift and while you may not think it, you are pushing into that category with your desired payload plus the extras.

The bottom line is that even though you chose bigger motors (880kv), and good 12 inch blades, lifting capacity is better handled by more disk area (AKA more motors and props) keeping the loading down per motor. Thus the Hexa frame is a much better choice still running 12 inch props. Just as a heads up, on my quad, ran 850kv motors but with 12 inch props and got better results than the recommended 10 inch props so the disk area idea does work. I was running an older 6600mah lipo pack from several years ago that is very heavy for a lipo, thus the reason for swapping blades. I simply could not get it to take off with 10 inch blades.

Get the frame+motors and props https://store.diydrones.com/ArduCopter_3DR_Frame_Motors_Kit_p/kt-ac...

Then just buy an APM 2.0 https://store.diydrones.com/APM_2_0_Kit_p/br-ardupilotmega-03.htm

Then get the telemetry kit (DIY drones has been out of stock a while).

I would get it flying and tuned before you started adding stuff like FPV and your drop system. Prove the aircraft first, get you flight times and payload sorted-then start adding your extras.

 

Look at it this way, the hexa is maybe $100-200 more the lifting capacity is much more siginificant than what even the 880kv and 12 inchs props can pull on the quad. It simply comes down to loaded disk area. You want serious lifting margin because controlling a load that heavy requires even more margin.

Same reason why big V8 engine exist when a V6 can make the same HP. Sure, the V6 does fine 90% of the time, but if you really are towing loads, the big V8 is the better choice and will last longer than a V6 wound out making max HP just to keep up. Let's be honest, when talking about lifting a copter that is going to weigh in at maybe 4 pounds with load, efficiency isn't our concern, we just want brute power.

• ▶ Reply

ModeratorPermalink Reply by Gary Mortimer on April 6, 2012 at 7:14am

Why not make it a boat that drags out your line as well and drops stuff when you see it on the fish finder.

You could have a hefty payload then.

A quad would be a very expensive way to go fishing. 

• ▶ Reply

Permalink Reply by bertjuh on April 6, 2012 at 7:26am

Thanks for the fast replies.

So it's all about the total torque/disk area. I wondered if i could manage with only 4 motors. Maybe 6 is better for really heavy loads, it must be able to hover steady, and have enough lift.

The thing is, i won't be adding stuff together, but i want a modular design. So no fishfinder + dropping mechanism, but 1 or the other. With easy replacement. First to scout the area with the finder, storing the good locations, then changing it for use as a dropping mech, so i don't have the finder on the frame when i'm dropping the lines/bait.

With that in mind, i want to use the uav/drone for multiple things, not only fishing. Plus, some fishing area's are relatively weedy at the side, so a regular prop boat would get stuck. So i would have to use an expensive jetpowered bait boat. (A fully assembled boat with finder is around 1000$ minimum, so a uav isn't that expensive.) Plus the uav will be autonomous with GPS. The boats are not. Quite handy when it's dark, and the GPS location is stored.

Frame + APM max 300gr. I really want lightweight. Maybe a carbon frame, if aluminium/titanium is too heavy. (Arducopter V1.0 = 250gr.)

Lipo (2S/3S) max 300gr

Motors + esc 350gr (4motors) or 500gr (6motors)

Total: max 2.1lb with 4 motors, or 2.4lb with 6 motors.

FPV max 500gr.

Dropper max 500gr payload.

So 1.1lb load max.

Absolute max = 3.5 lb. with load.

• ▶ Reply

Permalink Reply by Vernon Barry on April 6, 2012 at 10:21am

Your calcs aren't off but you are likely to want as much battery as you can get so don't even look at 2s, run 3S for sure and either small 2 packs 3300mah in parallel for 6600 or more. Heavy load, if each motor draws 20Amps times 6 120amps with 2 packs in parallel is a decent 20C discharge on the batteries, that's a rough flight time of 18 minutes, and being over water, you don't want less margin. Remember Lithum batteries will not take over discharge as it kills them dead. You also really don't want to load them over 20C and keep in mind you would use 60Amp rated connectors per battery. Deans are rated at 50A

Again, just throwing out some info I was looking at when building my hexa (using 850kv motors).

• ▶ Reply

Permalink Reply by bertjuh on April 12, 2012 at 1:47am

The things i now have on my shopping list here:

APM2

4 motors 880kV

4 esc 20 amp < is this enough, or should i buy higher amp esc somewhere else?

props 12x45

PDB for quad

 

For now, i don't have the need of any telemetry or video. Just enough to get started, and get the feel of it.

Is the Spektrum dx7 from the store here the original version or a clone/counterfeit? I read some warning about it.

 

 

• ▶ Reply