Long Endurance UAV design and discussions

[BHarwana]

I am starting this thread for a productive discussion in designing a UAV.
UAV were developed mainly for reconnaissance purposes and are quite effective to do the job but with limitations. The success of drones came as they prove to be a cheap platform for resonance and also kept vital human assets safe which have been put into danger other wise
The criteria this UAV meant to achieve are *** following.
The two main limitations of drones are what this thread will focus mainly on
1. How to maintain highest flight time.
2. How to maintain the highest flight time cheaply.
The secondary focus of this thread will be. The other fields this thread will focus is
What else drone can be used for military.
How to improve the drones and introduction of new technologies and how they can help improve drones.
The designing phase will include discussion on
1. Air frame design to maintain long flight times
2. Optics that can be used and how to improve them
3. Power plant design and what type of power plans should be used.
4. Communications and ground control for longer distances and what type of communication ground controls should be used and available technologies.
I am tagging in few previously interested members. Please don't try to derail the thread if anyone tries that he will be reported immediately and feel free to throw in your thoughts no matter how noob they are because sometimes you get the ideas from the places you can never except.
Below is the design which this thread will try to beat in the world record so lets keep the discussion productive.

February 5/16: The UK plans to buy two unmanned solar-powered aircraft, known as Zephyrs

, which are capable of carrying small payloads that might consist of reconnaissance cameras or communications equipment. The Zephyrs hold the absolute endurance record for un-refuelled aeroplanes staying up for 336 hours, 22 minutes and eight seconds. Developed in the UK by QinetiQ, the technology has been recently bought and marketed by Airbus with the MoD’s vote of confidence expected to lead to an increase in sales. High altitude, solar powered planes have often been used for civilian purposes by companies like Google and Facebook to deliver broadband to locations that lack fixed-line connections
http://www.defenseindustrydaily.com/zephyr-ultra-long-endurance-uavs-05426/

@Sheikh Rauf @Major Sam @mr.robot @Signalian @Windjammer

We will start this thread from the discussion and will later try to put a successful theory into practical use so lets see where we get. Please feel free to tag any members you think might help with their skills or interested.

 

[BHarwana]

The first part of the discussion will be air frame design to achieve long flight time.

Above is an image of a current drone that hold the record of highest flight time. It is electric powered and fueled by solar cells so lets take it as an example but please don't stick to the above design and think out of the box as well. One issue with above design is that it is a fixed wing design and has to constantly move.

Okay lets start with wing design.
A flat wing will give more lift and a swept wing will give more speed. this is the very first rule to follow. In case of surveillance a good design that provides good and easy lift is better than a design that provides more speed.

Now in this drone's case it has a good wing span and an intelligent design to reduce weight and drag the tail was replaced by adding horizontal control at the ends of the wings. this is the image of the latest drone which is developed by Russians.

 

[JamD]

I believe you are looking at this the wrong way. I am assuming you want this to be a Pakistani drone. Also, the mission requirements need to be more specific and availability of subsytems needs to be considered very seriously. This is how I would go about designing a reconnaissance UAV.

1) Identify the recon payload you have access to. Use this to get a figure of how high you could theoretically fly. Also you now know the payload weight.
You could make a UAV with an endurance of 24 hrs but if it flies at 30,000 ft to do so, and your payload can't see anything from that height, then you have a problem.
2) Identify the powerplant(s) you will have access to. Will it be a piston engine? A turbo prop? How hard is it to operate/maintain?
Not every powerplant will be available to you at a reasonable price. Do a preliminary design and answer whether the powerplant that is accessible can lift your payload to the design altitude from 1. If not, go back to 1 and find a lighter payload. If you do find an engine go to next step.
3) Refine your preliminary design
Is the preliminary design's layout good enough for the mission? Is the endurance good enough? Can you make the design better without losing too much time and money, or compromising on 1 and 2? For example, can you afford to invest in the advanced control systems you need for a flying wing design?
4) Do a detailed design
Figure out all the subsystems and where you would source them from. Is this platform still feasable? If not go back to 1, 2, 3.


You will have to go through these steps over and over again till you converge to a design which is "best" in some sense that you define it to be. The art of aircraft design is the art of compromise.

 

[BHarwana]

I believe you are looking at this the wrong way. I am assuming you want this to be a Pakistani drone. Also, the mission requirements need to be more specific and availability of subsytems needs to be considered very seriously. This is how I would go about designing a reconnaissance UAV.

1) Identify the recon payload you have access to. Use this to get a figure of how high you could theoretically fly. Also you now know the payload weight.
You could make a UAV with an endurance of 24 hrs but if it flies at 30,000 ft to do so, and your payload can't see anything from that height, then you have a problem.
2) Identify the powerplant(s) you will have access to. Will it be a piston engine? A turbo prop? How hard is it to operate/maintain?
Not every powerplant will be available to you at a reasonable price. Do a preliminary design and answer whether the powerplant that is accessible can lift your payload to the design altitude from 1. If not, go back to 1 and find a lighter payload. If you do find an engine go to next step.
3) Refine your preliminary design
Is the preliminary design's layout good enough for the mission? Is the endurance good enough? Can you make the design better without losing too much time and money, or compromising on 1 and 2? For example, can you afford to invest in the advanced control systems you need for a flying wing design?
4) Do a detailed design
Figure out all the subsystems and where you would source them from. Is this platform still feasable? If not go back to 1, 2, 3.


You will have to go through these steps over and over again till you converge to a design which is "best" in some sense that you define it to be. The art of aircraft design is the art of compromise.

I can under stand your point of view here but the path I am trying to take here is flying for more than a week so in that case the power plants would be electric and and fueled with solar cells. But to inform you I have access to jet engines, Piston engine, turbo prop, pulse jet and many other types they are available from the Chinese markets but that is not the direction I want to take the project to. Here I would like to stay with electric powered power plant.

Your first concern is exactly on point the discovery of recon payload is very important and that is the main issue here but that is why I have added to the section of optics and I know this will go in circles for the initial stages. That is why I have started a discussion first to asses what can be done. I have almost a design complete that can beat a the longest flight record but will come to that later before looking into more options.

The cost I have mentioned here can be achieved. the 30,000 ft altitude is not necessary because you have to only make sure that the enemy cannot shoot it down cheaply. If enemy shoots down the drone with 13x the cost of making than it is a job well done.

So the purpose of starting this project is to go through all aspects. If you are knowledge enough it will be a help for you to express your expertise.

 

[Hamartia Antidote]

Maybe something like this modified with solar.

 

[BHarwana]

Maybe something like this modified with solar.

You are almost on point where I plan to take it.

 

[BHarwana]

I would be interested in hydrogen from aluminium+water project to run small generators for those in need.

Chemical reaction works fine and there's enough information available on how-to, even the generic design of reaction chamber/device is available.

Happy to discuss and even sponsor the detailed feasibility.

@BHarwana ?

Okay reply here what are you saying.