FPV Tri/Quad rotor for law enforcement

[Gawlerj]

Hello, I've begun flying FPV with my fixed wing. I've only been into the hobby a few months and really enjoy it. I'd like to build/purchase a tri/quad rotor to use at my department. In a few searches for these pre-made for "law-enforcement" the cost is WAY out of range for our budget, 20K plus.

I'm hoping I could build something which can do what I think we need for a lot cheaper. But Since I know very little over all I was hoping to get some guidance here.

My goal would be to be able to fly within 1km of the base station.
Hold altitude and position. Remain airborne for 30 minutes.
Send video to the ground station and record hi-def on board (ground station would be a laptop running some sort of video capture software via a capture card.
Would be nice to have a zoom option on the camera, but not at first if it is cost prohibitive. Same with thermal.

Starting small (as in price) to get the concept down and decide if it is something we really need, and then being able to upgrade the same platform with added features would be a desired choice for me.

I'm hoping to be able to get this project "off the ground" if you will under 5k. Is this doable?

[FPVdude]

First you should start by doing some reading. Really get to understand multi rotors.

-My goal would be to be able to fly within 1km of the base station.
UHF control, 2.4 or 1.2 ghz video.
-Hold altitude and position. Remain airborne for 30 minutes.
Most controller boards do position hold, you could use NAZA, openpilot, or wookong. 30 minutes is tough, you would have to have all carbon fiber and a very big multi rotor. You can get 15 minutes on a small multi rotor with LOW kv motors (I would recommend around 750 kv) but this would make it move slower. Really not a problem in your application.
-Send video to the ground station and record hi-def on board (ground station would be a laptop running some sort of video capture software via a capture card.
I would recommend a small tv or goggles because you can't see a laptop screen in the sun. As for HD cameras, you have some options. You could use a wide angle cam, like a gopro. This would be better for searching because you simply see a lot in the field of view. However, if your trying to take a picure/video of a specific thing, you might be better with a not so wide angle camera. You will have to aim the copter and a pan/tilt might be necessary. You should probably start with a gopro because it's simply easier.
-Would be nice to have a zoom option on the camera, but not at first if it is cost prohibitive. Same with thermal.
They have a zoom FPV camera on foxtechFPV for $300. Not bad. Don't know where to get thermal cams though. Zoom would really be nice if you were trying to stay far away from something, but get a good view. Wide angle cams suck for trying to look at something small and far away.
End rant
Hope this helps

[Need4Speed]

research! my guess is that you could probably do it for under $1000? i think the half hour run time will be the hardest part

[Gawlerj]

Thanks for all the replies so far, Yes, I have much reading and research to do. But instead of reinventing the wheel I am hoping to get some guidance from others who have the experience I lack. I do appreciate the help. Maybe 15 minutes of air time will have to suffice, and that's ok if it's a realistic expectation of the current technology (at least at my budget!). I know HobbyKing is the low end of quality electronics but should I consider anything from them regarding this project? Their Prices are certainly attractive. But yes, I know, you get what you pay for.

[FPVdude]

If you decide to use 1.2ghz, then you can use an HK 900mhz receiver and a 1.2ghz vtx. Thats the setup i use, along with dragon link UHF. I'm not sure about 2.4, most people use lawmate brand tx and rx.

It's easier for us to help you if you ask a specific question, then we can give you a very specific answer that should hopefully help you.

[Bluerocktj]

Thermal imaging or FLIR is very expensive. Handheld models that I've used in the field can cost $3,000-$4,000. Here's a link for your information: http://www.flir.com/cvs/cores/compare/

[Flying Monkey]

Having flown a FLIR thermal imaging cam you'll want a Tau 640 and it's close to $10,000. As for the flight times, it can be done... The longest hover I've done is 25 minutes but I'm working on a quad that'll be able to hover for 45 minutes while carrying fpv gear and a gopro... PM me in a few weeks, should have it flying by then. Right now I'm still doing thrust stand tests. As for position hold and RTH you'll probably want the NAZA with the gps add-on... as a bonus its easy to fly for beginners (and non interested persons like my gf, lol).

[BacklashRC]

I am currently building a Hex with 28 minutes of fly time, fully loaded with FPV gear. Total cost for the Hex (not including the ground station or primary control radio is ~$2.5k). It has the ability to lift 11.5 pounds, in addition to its all-up-weight, for about 8 minutes. I will post additional details when I am not at work but I would start by saying, "Become intimately familiar with eCalc (http://www.ecalc.ch/xcoptercalc_e.htm?ecalc)".

The calculator will be frustrating at first, due to a new user's unfamiliarity with both the software, and efficiency considerations for multicopters. You need to start modeling potential aircraft, paying attention to things like craft weight, battery output impedence, prop pitch and diameter, etc,etc... Run your final build considerations by the forum members. You can easily spend a lot of money with no benefit if you are not careful. We may be able to help you avoid this.

[Gawlerj]

Again, to everyone, thanks for the replies! My chain of command has requested that I research this and provide a cost/build design. No time limit, but I'd like to get started.

I understand the cost of FLIR is high, but ultimately I could see it being purchased for this application IF the concept platform shows its potential. As stated, I would like to build a platform which could be "upgraded" to add these more expensive things. For starters a day cam with stabilization would be a goal.

BacklashRC, I was told there would be no math.... wow, what a calculator!

So, in addition to my reading and researching I think I'll try building a small version for myself. Sometimes my best way of understanding something is to build it.

Again, Thanks for the advise. I'm sure I'll have plenty of questions coming here soon.

[FPVdude]

So, in addition to my reading and researching I think I'll try building a small version for myself. Sometimes my best way of understanding something is to build it.

Great idea, you will learn a lot about what you like/don't like on your first build. A small quad or tricopter would be nice to learn on. For being upgradable a large quad or a hex would be nice. Are you thinking of doing a DIY frame or a kit frame?
I really like this project because if you can get more agencies to use drones, we should get better laws about them. Thanks!