Making a VTOL drone with good battery life and a camera that can stream/record

Thread Starter

-live wire-

Joined Dec 22, 2017
887
I have already explored the possibility of making a VTOL drone. However, I realize I had some unrealistic goals for carrying loads and such. So, I would like to maybe use a similar design, but scale the power down a bit for cost and practicality reasons.

Here are my goals for the end result:
-good VTOL, so quadcopter or plane-like operation
-allows for future additions like more sensors, cameras, etc
-good range and wireless control
-streaming at at least 720p and recording at at least 1080p60 (ideally with a zoom feature too)
-at least an hour of battery life assuming it's flying like a plane most of the time and at a reasonable speed

While I may want to scale down the power from the previous design, I was reading some articles, and "bigger is better". They said that smaller props are less efficient and large props push more area and have other advantages. Looking at the efficiencies of different motors, it seems to be much better with 10-15 inch props than 4-5 inch ones, which matches up with the articles. So the end result may end up being pretty large.

This means I would need help designing a good frame. It can't be too heavy but would need to be very sturdy, according to what others have said, meaning custom carbon fiber seems like the best option. I have minimal cad experience.

Also, I know the software would be difficult to get good, but I'm sure they're APIs and such I could use.

Also, this is a rough sketch of my previous design. The props would be 11-15 inches, and I'd use a frame with maybe a much thinner plastic for the parts that don't need reinforcement.

I'm thinking I could use servos to turn the motors, and have two back to back for more efficiency and canceling gyroscopic forces. I would also have it be fairly long and with good supports so it can turn it well. I would try to keep the batteries where it would allow for the center of mass to be in the center of the 4 motors.

Does anyone have any recommendations for what I could change with my design?Screen Shot 2019-11-07 at 12.24.37 PM.png
 

gramps

Joined Dec 8, 2014
69
First off, what is your definition of "good range". 100 yards? 1 mile? 10 miles?
Second, one hour or more flight time is bordering on unrealistic for what you are proposing. Longer flight times require more battery capacity which is more weight which requires more battery capacity for the same performance. There is a point of diminishing returns where larger batteries provide very little benefit. The larger the aircraft, the less noticeable this is though.
I think I would do away with the tilting rotor idea. For a craft of this size it adds a lot of complexity and weight to the design. I'd stick with a hex or octocopter design. There is a ton of info on such designs of the net.
Good luck with your endeavor.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
First off, what is your definition of "good range". 100 yards? 1 mile? 10 miles?
A few 100 yards, but I need it to go back to an estimation of the controller if it gets out of range or disconnects.

Second, one hour or more flight time is bordering on unrealistic for what you are proposing. Longer flight times require more battery capacity which is more weight which requires more battery capacity for the same performance. There is a point of diminishing returns where larger batteries provide very little benefit. The larger the aircraft, the less noticeable this is though.
I see what you're saying. However, can't you get that kind of battery life if you have it fly like a plane using lift and such? I saw some plane drones with very good battery life. So if it was in a plane-like mode of operation, couldn't it get similar battery life?

I think I would do away with the tilting rotor idea. For a craft of this size it adds a lot of complexity and weight to the design. I'd stick with a hex or octocopter design. There is a ton of info on such designs of the net.
I see what you're saying, but it seems like there would be some advantages to having it be like a real plane or real quadcopter, instead of something in between. And I'm sure someone else has done something similar. But also, what if only the front ones moved, and the back 2 or 4 were stuck facing up? Something like this? That way it can take off vertically but only needs two of the servos to rotate it.
 

jpanhalt

Joined Jan 18, 2008
7,874
I vaguely remember reading that 45 min duration was close to the maximum achieved for a pure multi-rotor drone a few years ago.

At some point, long duration VTOL/hovering drones will need generator/battery systems. Efficient, gasoline or diesel engines with generators (including alternators) may also be practical. Given the necessary speed for response, I do not think independent IC engines will work well enough for a stable platform; however, a single engine with electrically controlled prop pitch might work or a main propulsive IC engine with battery powered attitude control might be an alternative.

It seems you are talking about something quite expensive or a lot of experimentation.
 
My hundred different companies have done this already , in many different sizes . To produce anything close to what is already available would require great dedication and high expertise ...If you want to assemble yourself there are many modules available ...

Generally as size goes up so does range and fly time ... think big !

Going for VTOL will restrict you greatly , since in horizontal flight the plane is also carrying the heavy motors and props required for hover .... going for a airplane design the motors can be small and light , hence further range.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
Going for VTOL will restrict you greatly , since in horizontal flight the plane is also carrying the heavy motors and props required for hover .... going for a airplane design the motors can be small and light , hence further range.
Thinking about the practical uses for it, having it be able to hover is very important. While I can use editing to zoom in a bit and digitally stabilize it if necessary, I can't get a stable shot from something that is moving around. I also might want to just fly it around for fun or to get a moving video of something.

So, I don't think a plane-like design would allow for a stable still shot. If you know of any way to have it fly around in a circle and get a relatively still shot that would be great, but then a camera rotating system would be difficult to do DIY. If you know of any solutions out there for plane drone still images that would be great. I know they can be much lighter and better.

However, it seems like a quadcopter design is even worse than VTOL in terms of flight time, based on what you're saying and what I've found looking around. So, maybe a design like quadcopter with wings or only on or two moving motors would be best. This way, I can make the quadcopter-like design required for hovering the most like a plane drone. 1573346896118.png
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
I vaguely remember reading that 45 min duration was close to the maximum achieved for a pure multi-rotor drone a few years ago.

At some point, long duration VTOL/hovering drones will need generator/battery systems. Efficient, gasoline or diesel engines with generators (including alternators) may also be practical. Given the necessary speed for response, I do not think independent IC engines will work well enough for a stable platform; however, a single engine with electrically controlled prop pitch might work or a main propulsive IC engine with battery powered attitude control might be an alternative.

It seems you are talking about something quite expensive or a lot of experimentation.
I'm really not looking to do anything with IC engines due to complexity, risk, cost, weight, and many other reasons.
 

jpanhalt

Joined Jan 18, 2008
7,874
I have no problem with adding a wing, but the V22 Ospey that combines VTOL w/ forward propulsion has been a "complicated" development for the US. The AOA of the wing could be such (i.e. high in vertical flight) that with slight tilt forward its AOA would produce enough lift for stable forward flight. I am still skeptical.
 
A range of " a few hundred yards" is very realistic with available hobby RC transmitters. That shouldn't be any problem.
Your design of an airplane with 4 fixed in place upward rotors is interesting, although in the 20 years that I've been involved with RC aircraft, I've never seen anything like that. Doesn't mean you couldn't build it yourself. It would take a lot of experimentation to get it to work. Again, if your really looking for flight times of an hour or so, bigger is better. On the plus side, larger RC aircraft are easier to control than smaller ones. On the down side, they are more expensive to build and repair after the inevitable crash.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
A range of " a few hundred yards" is very realistic with available hobby RC transmitters. That shouldn't be any problem.
Your design of an airplane with 4 fixed in place upward rotors is interesting, although in the 20 years that I've been involved with RC aircraft, I've never seen anything like that. Doesn't mean you couldn't build it yourself. It would take a lot of experimentation to get it to work. Again, if your really looking for flight times of an hour or so, bigger is better. On the plus side, larger RC aircraft are easier to control than smaller ones. On the down side, they are more expensive to build and repair after the inevitable crash.
How do I reduce the damage of a crash, and could I test hovering in my basement with ropes attached or something? Is there a type of prop guard you recommend?
 

jpanhalt

Joined Jan 18, 2008
7,874
How do I reduce the damage of a crash,
Some people use training gear like this:
1573570395831.png

and could I test hovering in my basement with ropes attached or something? Is there a type of prop guard you recommend?
I would not recommend doing that. Too many things to hit and damage your aircraft. Local clubs rent out field houses for Winter flying. You might be able to use a gym.
 
Multi-rotor RC craft are usually controlled with flight controllers. These devices contain the sensors and circuitry to control the craft based on inputs from the pilot's transmitter. They make flight a whole lot easier. It would be nearly impossible for a human to make the necessary inputs to control a 4, 6 or 8 rotor craft effectively without a flight controller. Google them, there's lot available.
For the size of craft that you are looking to build, I wouldn't even think of testing it indoors. That would be far too dangerous. Remember the propellers are like knife blades rotating at high speed. Prop guards on props of that size are basically worthless. Don't waste your time with them, just learn to fly it.
The only way to become "good" at flying RC aircraft is to actually fly them. Fact of the matter is, when learning to fly RC, you will crash. Your best bet is to learn to fly conventional RC airplanes and quadcopters first and then use those skills to fly the plane that you are proposing. That will save you a lot of frustration and money. Are you in the USA?
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
Multi-rotor RC craft are usually controlled with flight controllers. These devices contain the sensors and circuitry to control the craft based on inputs from the pilot's transmitter. They make flight a whole lot easier. It would be nearly impossible for a human to make the necessary inputs to control a 4, 6 or 8 rotor craft effectively without a flight controller. Google them, there's lot available.
For the size of craft that you are looking to build, I wouldn't even think of testing it indoors. That would be far too dangerous. Remember the propellers are like knife blades rotating at high speed. Prop guards on props of that size are basically worthless. Don't waste your time with them, just learn to fly it.
The only way to become "good" at flying RC aircraft is to actually fly them. Fact of the matter is, when learning to fly RC, you will crash. Your best bet is to learn to fly conventional RC airplanes and quadcopters first and then use those skills to fly the plane that you are proposing. That will save you a lot of frustration and money. Are you in the USA?
ok
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
Have you seen this video? I just stumbled across it and thought of your idea. See post #1867

That looks interesting, I might want to try something like that. And it's good to know that it can be done. But did the wings have flaps to help with flying, or did it just adjust the 4 motors? Because the extra weight and complexity seems undesirable, but I'm wondering if it's neccacary.
 
That looks interesting, I might want to try something like that. And it's good to know that it can be done. But did the wings have flaps to help with flying, or did it just adjust the 4 motors? Because the extra weight and complexity seems undesirable, but I'm wondering if it's neccacary.
If the craft has vertical T.O. capability without flaps, why does it need flaps in flight? I would leave the flaps off, unless they are part of thrust vectoring.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
887
If the craft has vertical T.O. capability without flaps, why does it need flaps in flight? I would leave the flaps off, unless they are part of thrust vectoring.
Ok, great. I just saw them on a lot of VTOL drones when googling "VTOL drone" and thought they might be necessary for good efficiency.
 
Flaps aren't used when flying. They increase lift at the expense of additional drag. Not good for efficient flight. They are normally only used during takeoff and landing, but in your design with 4 rotors they might be beneficial to provide increased lift during the transition from vertical to horizontal flight and back.
 

jpanhalt

Joined Jan 18, 2008
7,874
@-live wire-
Flaps move the center of lift aft, the nose drops, and drag increases. The effect at very low Reynolds numbers on maximum lift is pretty limited. Even with highly efficient wings as in molded competition sailplanes, deployment on launch and while thermally is minimal. Their main use is for drag to facilitate spot landings with the nose pointed down with respect to the horizontal. Also, model airfoils for soaring are often cambered to begin with. For speed, one reflexes the flaps a little.

If you review aerodynamics, most of what you find will be for full size airplanes with higher Reynolds than your model will likely have. Data for low speed airfoils are available. Over the past 30+ years, the two American engineers who contributed most notably (IMHO) to data for model airplanes are Michael Selig (U. Ill, Notre Dame) and Mark Drela (MIT),

Here are some references you might find useful:

Michael Selig Soar Tech 6:
A more readable summary:

Michael Selig Airfoil database:

Mark Drela Sizing "Checks" (No need to register, just scroll down):

General Discussion by others (large aircraft):

Soar Tech 6 used to be available in soft cover ( I have a copy), but it may no longer be in print. The opening page is a cartoon that on casual inspection may look like a knife stabbed into the ground. Closer inspection will reveal it is a competition sailplane "dorked" into the ground for a spot landing. Since it is very close to the nail, it got high points for the landing, hence the joke.
 
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