Check out this quadcopter drone that's fired from a cannon

[midian182]

In brief: Drone technology is advancing all the time, but one of the problems still being looked at is how to get them up into the air safely in certain scenarios. The potential answer, it seems, is to use a cannon.

The device was created by engineers at Caltech University and NASA’s Jet Propulsion Laboratory in California. Called SQUID—an acronym for Streamlined Quick Unfolding Investigation Drone—it looks like a tiny missile during its launch stage.

The SQUID measures just 10.6 inches in length and weighs 1.12 pounds, and the cannon that fires the drone is a pneumatic baseball pitching machine that’s been modified. It’s able to launch the SQUID at 35 mph, and it can be fired from a stationary position or from a moving vehicle traveling at up to 50 mph.

Less than a tenth of a second after it’s launched, the drone’s spring-loaded rotor arms open out, and the internal motors give it powered flight.

In a research paper, the team writes that the quadcopter would be perfect for use in crowded environments as the operator can direct the launch path, so the device avoids any collisions.

It’s also suggested that the SQUID could have applications in the field of emergency services. It could be used for space exploration, too, where launching it from a rover vehicle is an option. It’s noted that NASA is already planning to deploy a powered rotorcraft machine from the Mars 2020 rover. Additionally, the military might be interested in being able to launch surveillance drones from vehicles without them needing to stop.

The SQUID is 3D printable and scalable, though the only issue it might have right now is landing. It has no landing legs, but “can safely land if the bottom touches the ground first at a low speed,” at which point it gently topples over.

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https://www.techspot.com/news/82891-check-out-quadcopter-drone-fired-cannon.html

 

[stewi0001]

That's pretty neat, and the noise it makes is hilarious. XD

 

[Uncle Al]

Excellent .... I can see a LOT of applications, especially launch-able from a moving platform. Might be a bit too noisy for military applications but that depends on how / where it's used. Would be exceptional if it has a good quality camera and air time of 60 minutes, especially on the boarder and other places where E&E need to be combated ......

 

[DjoCoeur]

You can also use a canon to bring it down.

What I'd like to see is a drone that could fly in the atmosphere of Mars. I know the density is like 100 times less dense but the gravity is roughly one third that of the Earth. So it might be possible one day for a drone to fly there with larger propellers. It could be much more efficient than the actual rovers able to cover only a few meters a day (sol).

 

[captaincranky]

....[ ]... Might be a bit too noisy for military applications but that depends on how / where it's used.

Oh, I don't know, methinks the noise would be useful for a flanking maneuver. Send a couple of dozen of the noisy little biddies to one side of an HVT. People will be too busy trying to shoot the damned things down, they'll never see or hear a couple of Predators coming from the other direction.

The heck with the camera. Load em up with M-80s. People will believe they're worth shooting down if they think they're being fired on..

 

[neeyik]

I know the density is like 100 times less dense but the gravity is roughly one third that of the Earth. So it might be possible one day for a drone to fly there with larger propellers.

The magnitude of the lift generated by the blades of a helicopter is directly proportional to air density; so reduce that by a factor of 100 and you would need to do any of the following changes to counter this:

Swept area of blades = 100 times bigger
Air speed = 10 times faster
Coefficient of lift = 100 times bigger

The first one would require blades 5 times longer, which isn’t entirely impossible, especially if you then factor in the lower gravity. Combined with a small increase in air speed, a large bladed copter would be viable on Mars. It would have to turn pretty slowly though.

 

[captaincranky]

The magnitude of the lift generated by the blades of a helicopter is directly proportional to air density; so reduce that by a factor of 100 and you would need to do any of the following changes to counter this...[ ]...

While I'm going to assume the "air is 100 times thinner", is reasonably accurate, neither you, or the gentleman you're quoting have taken Mars' much lower gravity into account. Which is likely one of the biggest factors to consider.

Having witnessed our moon landings when they happened, (yes, I'm that damned old), I was struck by the minuscule primary engines in the lunar lander required to launch it back to rendezvous with the lunar orbiter , in comparison to the monstrous 1st stage engines in the Saturn V, required to get the whole shebang off the ground in the first place.

Mars escape velocity is less than half that of earth, in addition with not having to deal with as much atmospheric static drag, or lift induced drag from the rotor blades, (or possibly wings).

There's another wild card in requirements for flight on Mars. Mars' atmosphere is primarily Carbon Dioxide, and a fair amount heavier than earth's nitrogen / oxygen mix. So you get more lift sooner.

Another factor in flight is "proximity effect", whereupon the closer you fly to a hard surface, the more lift an aircraft of the same airfoil, speed and weight, is developing.

Granted the requirements to fly on Mars would be very difficult, but perhaps not nearly as dramatic as you're imagining them to be.

Can I do the math to prove any of that? No, I cannot, sorry.

 

[neeyik]

The lower gravity is factored in - it is the reason why the density is 100 times lower at the surface. However, like for like, comparing the lift required on Mars to that on Mars, one simply needs 3 times less lift for the same mass. The same lift requires 100 times more swept area so on Mars it would then be 33.3 times more area. This would require the blades to be 2.88 times longer.

 

[captaincranky]

The lower gravity is factored in - it is the reason why the density is 100 times lower at the surface. However, like for like, comparing the lift required on Mars to that on Mars, one simply needs 3 times less lift for the same mass. The same lift requires 100 times more swept area so on Mars it would then be 33.3 times more area.

So you redid the math then? Because that's not what I got out of your post #6. Granted I have had a bit of rum, Perhaps I missed it.

This would require the blades to be 2.88 times longer.

This is arbitrary to the point of ignoring aspect ratio and the inverse square law altogether. I'm nitpicking, sorry. But, merely lengthening the wings would create issues with structural rigidity. Not to mention the wider the wing or blade, the more lift it will produce per square measure.

As an example, a scale model of an F4U "Corsair" (@ 1 1/2" to the foot), would be a handful to fly coming in at a wing loading of perhaps 46 ounces per square foot. The full scale F4U is likewise, (or so I've read), a handful to fly. But it's wing loading is 30 pounds per square foot dry, and approaches 40 lbs per sq ft, gassed up and armed.

Besides, it wouldn't make sense to compare aerodynamic requirements as mars to earth anyway. Mars to Mars is the only legitimate comparison.

The devil is in the details, or so I've heard.

 

[neeyik]

So you redid the math then? Because that's not what I got out of your post #6. Granted I have had a bit of rum, Perhaps I missed it.

Yes, my fault - the original post was done on phone and I'm desperately awful at writing on them. It was missing the adjustment for the reduction in gravitational field strength.

This is arbitrary to the point of ignoring aspect ratio and the inverse square law altogether. I'm nitpicking, sorry. But, merely lengthening the wings would create issues with structural rigidity. Not to mention the wider the wing or blade, the more lift it will produce per square measure.

I would argue that it both is and isn't arbitrary. You're correct in pointing out other factors that would have to be considered but I was looking at it purely from the point of how atmospheric density would affect the viability of a copter on Mars, in response to DjoCoeur's remark. The physics of helicopter flight can be read here and equation 10 was the one that I used, as it covers the simplest element of copter flight: hovering.

You can see from the equation that the thrust is directly proportional to atmospheric density, swept area and the square of the induced rotor plane air velocity; swept area is, of course, proportional to the square of the blade length. So just on the basis of atmospheric density and effects of gravity, a viability check of the use of helicopters on Mars 'simply' requires rotor blades approximately 3 times longer than equivalent ones for use on Earth.

So it's viable, but as you pointed out, arbitrarily so because the rest of the flight dynamics of a copter is a lot more complex than a single thrust formula. That all said, blades 3 times longer would factor for the difference in atmospheric density and gravity for the simplest mode of flight.

There's another wild card in requirements for flight on Mars. Mars' atmosphere is primarily Carbon Dioxide, and a fair amount heavier than earth's nitrogen / oxygen mix. So you get more lift sooner.

This is accounted for by the atmospheric densities. Turns out that Mar's atmosphere is actually 60 times lower than Earth's at ground level, not 100:

Mars Fact Sheet

Earth Fact Sheet

Mars: surface density: ~0.020 kg/m3
Earth: surface density: 1.217 kg/m3

Granted the requirements to fly on Mars would be very difficult, but perhaps not nearly as dramatic as you're imagining them to be.

Not sure how you managed to read that from my post - especially since I was pointing out that it's certainly viable! - but to be honest, flight mechanics is the least concern. Pretty much all machines on the surface of Mars are semi-autonomous, and a little (or large) copter would have to be the same. For ground based vehicles, any potential path finding glitches are managed by just having the vehicle move really slow; probably aren't able to do this for any sustained atmospheric flight, so the flight control systems will need to be top notch.

Edit: Back on the topic of the news piece, I was initially not convinced by the whole cannon idea, but having watched the video a few more times, I can see situations where launching a copter from ground level could create risks that are mitigated somewhat by use of the cannon.

 

[captaincranky]

@neeyik OK, you obviously have a much better grasp of advanced mathematics, than do I. In fact, I can do algebra 101 as long as I'm in a classroom with an instructor, but unfortunately, forget what I learned the minute the bell rings, and I walk out the door.

However, I am an aircraft "groupie", and was involved in radio control modeling, (fixed wing craft though) for a good number of years. (I'm thankfully, in remission now. That sh*t's really expensive).

But I have a practical understanding of aerodynamic principles, in the arena of task purposed planform, wing aspect ratio, airfoil type, (which BTW there is entire book of numbered and approved cross sections), and other factors.

The idea of "3 times longer blades", bring up the perhaps somewhat or distantly related design differences between our (the US), 2 primary spy planes, the U-2 and the SR-71, both of which have completely different solutions to flying in very thin air.

The U2 was (is, I think NASA still flies an example), essentially a glider with, "3 times longer wings" <(hyperbole), and while I"m fairly certain ground fire won't be an issue on Mars, became easy to shoot down. When the U2 is on the ground, (granted in earth's heavier gravity), pogos have to be placed under the wing tips to prevent drooping and damage.. Which sort of highlights the structural issues which might be created by a massive lengthening of rotor blades.

Thus, what I"m suggesting is that a compromise or compound solution may be necessary to achieve flight on the red planet (Plus we'll have to run a USB charging cable between the earth and Mars if we want it to fly more than once <(Joking))..

For example a quadcopter might have to be designed with wider blades as opposed to longer or a compromise between the two factors, as well as specific airfoil design to achieve "liftoff" in the Martian atmosphere.

Here's a few designs that can safely be ruled out:

....Edit: Back on the topic of the news piece, I was initially not convinced by the whole cannon idea, but having watched the video a few more times, I can see situations where launching a copter from ground level could create risks that are mitigated somewhat by use of the cannon.

I still like the idea of using them as a diversion to draw enemy fire, while another type of craft goes in for the kill. OK, so that's a bit bellicose and misanthropic (**) but likely workable.

(**) Both ingrained aspects of my basic belief system

 

[DjoCoeur]

On the other hand, wouldn't it be much easier to start by using gas to achieve flight on Mars. It would be very easy to do. Once landed, unfold and inflate some kind of small Blimp. Then they would be able study the atmosphere, winds, weather and the terrain for months, covering millions of KM. For sure it could take thousands of amazing HQ pictures much better than a satellite. I guess Hydrogen could do the job in Mars' atmosphere and the skin of the blimp could actually act as the solar panel.

 

[captaincranky]

@DjoCoeur Well, yes that's good idea. However, every type of aircraft is susceptible to weather conditions, blimps more than most due to their slow flight speeds. I'm not saying a conventional winged aircraft or helicopter type vehicle would be much faster as designed for flight on Mars, but it would have less of a cross section for air currents to interact with.

Plug this search term, "Are there winds on Mars", into your favorite search engine, and see what conclusions you draw from the results.