I would be interested in doing a glider UAV that allows me to have greater autonomy as possible.
I have no limitations wingspan, even 5-6 meters. I have no need for rear propulsion, but more efficient classic front version.
So I'm looking for a model that allows me to get amazing results as autonomy. I was also thinking of combining the photovoltaic cells later, but not now.
I have already developed models that allow me to make a 6 hour flight and I would like to reach the 18-hour flight.
I know it is very difficult.
I have a budget of $ 3000-4000 for motorization, airframe and batteries.
Interesting question. What method did you use for 6 hour flights?
For an airframe, maybe you can ask Matthew Coleman. He is using a 5m e-glider, but I can't remember the type.
I am working on longer flights using autonomous thermalling.
I am flying a Valenta Thermik XXXL. It is the full carbon wing and kevlar fuselage version. Total flying weight is 6.5kg. Full power takes ~2.4kW from the 6s battery so there is no problem hand launching. Airframe cost is ~1000Euro which is a complete bargain. It cost an extra ~1000Euro for motor, battery, servos, radio and a mile of cable for wiring.
Flight time is only 90mins from 2s 2200mA LiPo radio/servo battery. That is about 12Whr. A charger between the motor battery and the rc battery will be needed for longer flights. The main battery has ~88Whr so 6hrs is possible,
Most of my flights are limited to an hour because that is as long as I can cope with flying it. Mostly I fly an assisted mode or manual. The only autonomous flying is RTL which happens quite often due to loss of rc radio contact.
Valenta Thermik XXXL http://www.valentamodel.cz/50a.htm
Despite the size of this aircraft there is very little space inside. An APM or pixhawk does not fit. I use a UDB mounted on a slide in electronics pod under the wing. The pod also carries the rc receiver with the 2.4G antenna which poke out of the fuselage behind the wing.
There are significant challenges for this more complex airframe. The mixing has to be placed on the autopilot. I built a mixing system that can be configured through mavlink, together with a gui to drive it. I can't recommend this setup to anyone unless they have a high pain threshold.
A scale model has much larger fuselage volume and simpler airframe controls. The old SBXC is a classic compromise.
I'm thinking of buying Thermik XXXL and expand the fuselage so that I can insert a 6s 30'000mah assembled in the house with the weight of 3.2kg. I used a Grafas 3 meters with 3S 11'000mah and I got excellent results, but without autopilot and continuous research of thermals.
I'm trying to achieve the 10 hours, or even more .. with autonomous flight without research of thermals, but with very low power consumption of the motor.
I'm seeing to use motors from quadricopters with low kV and with large propellers and with great batteries. I'm seeing whether it makes sense to use motorization 8s or 10s.
Look forward to comments and advice.
You say that the SBXC airframe, allow me get the performance that I need without make too many modifications on the fuselage..
This will work...http://mrt247.wix.com/project-arrow
We may be able to come up with an affordable solution for you if you're interested in working with us. www.xair-robotics.com
Feel free to shoot me a PM on here or an email at the website I linked to.