I'm an amateur radio operator (K7AAY) specializing in emergency services work, seeking a way to loft a repeater for fire fighting support and other emergency services work. We get wildfires and the state rado net has big gaps in canyons and the boonies.Any design would compete with current state of the art, i.e., a weather balloon, a tank of helium and the tether with a wire carrying 500ma at DC voltage adequate to deliver 8.4VDC to the transceiver (an HT or Handheld Transceiver and a controller board) on the weather balloon.How much mass can I squeeze into a UAV?What's the optimum design?1) Solar cells on fabric to also run an electric motor for sterage on a lighter-than-air craft2) a larger LTA burning hydrogen from the envelope to run a motor with a small generator set as well as an engine for steerage, or3) a multi-engine heavier-than-air craft with larger than ususal fuel capacity?
aiming at something small cheaper and without a COS to demo proof-of-concept, then we worry about involving The Powers That Be for a COS and a bigger bird. Plenty of opportunities for using a 400' AGL bird in the work we do.
It sounds like what you want is a UAV as a high-bird. In the type of terrain you're talking about, I don't think 400'AGL would be enough. You should think more along the lines of 4,000-6,000'AGL. In a wild fire situation, there should already be a TFR over the area to allow fire helicopters and tanker aircraft to operate in the area without having to worry about news helicopters or pilots rubbernecking. You probably need to keep your UAV above the other aircraft operating in the area.
The other advantage of being at the higher altitude is that you'll be able to cover a wider area. The downside to this is that a handheld won't be nearly powerful enough. All of a sudden you're probably talking about something more akin to a mountain-top repeater, which would weigh a lot more and take quite a bit more power.
I think your best bet is to get plugged into the air branch of any local incident command center. I bet your local RACES group has some in-roads there.
This sounds like a great use of this technology to me, but it also sounds like a huge undertaking. Good luck.
@john: I would not go solar if I was you, they are heavy and ineficcient for anything other than research aircraft. I would use 4 stroke or indeed diesel as Sgt Ric suggested and driving an alternator off it to power everything.
Solar would also not work well if you have smoke blocking the sun or bad weather.
Varga, no need to apologize for showing milspec gear. We have civilization available to us because rough men and women stand ready to stand between us and those who would do us harm - updating George Orwell.
http://solarworld.com/SolarMini-Panels%26Motors.htm $96 + frt gets me six of the 4-3.0-100 panels.. three in parallel, then two triplets in series gets me 200ma at 9v in 56 square inches of wing surface, or raw DC voltage suitable for 20% duty cycle on a one watt repeater. Without urban chatter competing to drive up the background floor, very reasonable power for the repeater and its controller. East of the Cascades, sunshine is plentiful... although fire soot on the cells will be a problem.
This month's copy of Fly RC has an article about Bob Davis (of Davis Diesels) who has long worked with the military of UAV powerpalnts and is quoted on the ability of a diesel RC engine to fly for 24 hrs on one gallon of fuel AND turn an alternator for on-board power for the telemetry and video downlink.
@john, from the proposed utilization I would say single motor 4 stroke fixed wing airplane, with 2-2.5m wingspan, but a glider hybrid with gliderlike wings but more like a trainer body, this would give tons of lift, and therefore minimize fuel consumption.
A plane that size can easily keep quite some payload up in the air for a long time if you have a large fueltank.
That could then be programmed to circle an area at a set altitude until fuel is low, and then return to base or be flown manually back. Would need some filtering on the intake air to remove the carbon etc if it flies over a forest fire or similar.
It could also of course be fitted with a camera pod with steerable IR thermometer or other similar sensors which could turn out useful.
I believe the main issue for something like this would be the support personnel and service to the vehicle. It would have to be very sturdy and field friendly which is generally something hard to put together as a one-off or without a design team and industrial manufacturing processes - at least in a user friendly way
Hey John....If you can, send me a little write up of your idea. I think I might be able to help you out a bit. I'm a cartrography and GIS major. I was also in the Massachusetts Emergency Management for a while. I'm doing my Senior Thesis on drones and building one for Cartography and Remote Sensing purposes, but I think I can build a system that can do what you want too. jwraymond@gmail.com
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The other advantage of being at the higher altitude is that you'll be able to cover a wider area. The downside to this is that a handheld won't be nearly powerful enough. All of a sudden you're probably talking about something more akin to a mountain-top repeater, which would weigh a lot more and take quite a bit more power.
I think your best bet is to get plugged into the air branch of any local incident command center. I bet your local RACES group has some in-roads there.
This sounds like a great use of this technology to me, but it also sounds like a huge undertaking. Good luck.
Solar would also not work well if you have smoke blocking the sun or bad weather.
A plane that size can easily keep quite some payload up in the air for a long time if you have a large fueltank.
That could then be programmed to circle an area at a set altitude until fuel is low, and then return to base or be flown manually back. Would need some filtering on the intake air to remove the carbon etc if it flies over a forest fire or similar.
It could also of course be fitted with a camera pod with steerable IR thermometer or other similar sensors which could turn out useful.
I believe the main issue for something like this would be the support personnel and service to the vehicle. It would have to be very sturdy and field friendly which is generally something hard to put together as a one-off or without a design team and industrial manufacturing processes - at least in a user friendly way
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