Jonfliesgoats

This: https://en.m.wikipedia.org/wiki/Galvanic_anode

High pressure, temperature and low pH are within our capabilities to handle. Assuming you survey a sesource rich area, I think strip mining may be in order. I also like using robust, tethered balloons and turbines for energy. I am still unclear why charging our devices positively while allowing some disposable metal to oxidize away wouldn't increase the lifespan of our expensive stuff in a charged shell. What fundamental aspect of chemistry have I forgotten? We used to do something similar with fences on farms. As an aside to this, I have discovered that most fellow homesteaders have forgotten about using a rust wire to preserve a fence (sacrificial anode).

Perhaps. What about paragliders? We have GPS guided ram-air parachutes for precise deliveries here on Earth. It is entirely conceivable that a paraglide could be used for deliveries to locations on mars. A paraplane would be deliverable to Mars too.

Balloons on Venus too.

Officially it was going to be used for search and rescue. It was actually marketed for clandestine and special operations. No need to get someone through a border checkpoint when they can inflate a plane and fly out. It was air-droppable, easy to use and easy to fly. It could also operate from water. The practicality of this waned as helicopters became more capable. Also the benefits of flying a weirdo out of E. Germany or China in an inflateable plane are offset by the difficulties of getting an inflateable airplane to them. Still, I always wanted to fly one. I wonder if it made a balloon-like "Poing" sound if you bounced a sparrow off of it? The noise from the motor (which also had a top-up compressor) would have drowned out my desired "poing" though.

Mostly at airshows through my previous life. If you are one of the guys who flies a plane with doodads to a given location to talk about a widget to potential customers, you talk to other folks too, including cosmonauts. Now that my current life simply has me flying as an airline pilot, I found we actually have one working here. He started working in the West during the rough Yeltsin years. Hang out around airports and talk to strangers, you'll meet a lot of interesting folks. You'll find that many stories people dismiss as BS are actually true, too. Turns out there are very few boring people out there, and most of us seem to do amazing things. Same holds true if you are working at airports too. Lots of information to be gleaned there. That's one thing that amazes me. These people, information, devices are much more accessible than people think. You just sort of stumble into things as you poke your nose around, ask questions and generally engage in noseybusiness. Criminals do this too, in different ways. Frequently talking about valuable freight puts people like truck drivers in third world countries at risk. That's observation is to another discussion, though. @Rath If you are so inclined, you could go snoop around trade shows, etc. You'd be surprised what you can do if you're willing to look a little silly in the process.

I poke fun, but I have a healthy respect for anyone motivated enough to build their own helicopter powered by rockets. It's more than I can do in my spare time.

This too: Now I ask you this: How is building one's own liquid fuel rocket any more ridiculous than building these things? Speaking of rockets, this:

Anyone want to weigh in on these homebuilt helicopter ideas? Let's live up to the examples set by our brave Kerbals! Gyrocopters not included. http://alternative-technologies.org/aircraft.php Also, this:

When I was a kid, I remember learning about inflateable planes made by Goodyear. Another thread had us discussing hybrid craft on Mars. I thought some of you may enjoy learning about an interesting airplane project from the 50s. http://slightlywarped.com/curiosities-the-inflatable-plane/

Wait, so you're saying a positively charged object is still going to react with an acid? Aren't we changing the reduction potential of exposed metals?

For people concerned about turning an airplane at high altitude and speed, there are complications but they are not as severe as one may think. The turn radius of a given plane on mars will be wider due to the higher true airspeeds involved. The forces, however, are no big deal. A plane banking fifteen degrees on Mars will feel the same forces as a plane banking fifteen degrees on earth. With respect to coffin corner, a previous post rightly said that the problems there are manageable. So while we may not be flying aerobatic routines on mars, we actually can fly and get around alright. As another person said, getting a plane delivered there and recovering it are more challenging than flying and propulsion. A Martian helicopter could be more feasible.

There are hybrid options too. Heavier than air, lifting blimps. for example. If we want to fly something on Mars, be it a plane, helicopter or blimp, it's actually not that tough to do initially. Logisticallly, getting runways for planes would be tough. Finding smooth places without pointy things could complicate life for blimps too (even mooring to a tower, eventually the blimp needs to come down for servicing.). In the seventies a Martian plane project was proposed that was going to use hyperbolic fuels in a reciprocating engine to power some sort or reciprocating motor with a propeller. Today and in the near future, electric motors with lightweight batteries and solar arrays on wings may do more.

Yeah. In airplanes active boundary layer control was experimented with the control drag by blowing gasses at specific locations to energize lower layers of flow and prevent flow separation. Still not sure about exhaust gas velocity, which is important though. Why do you want to have a rocket motor thrusting on top of or in the middle of your rocket? What's the application you are considering?

So we need 540N of thrust to maintain level flight, assuming our rough estimates of drag ar somewhat close. Now we have to figure out whether we can squeeze enough thrust out of a motor and energy source light enough to do this. So let's see what sort of prop we need to generate enough thrust on mars! Well, that really depends a lot on motors, propellers and other things. Suffice to say that current electric props, especially in multi-engine arrangements can meet the energy demands of your Martian plane. So can we fly a plane on mars? Yup.

So we talked wings. Now let's talk drag and thrust! A typical drag coefficient for a decently designed plane can get pretty low. Drag and airplanes is complex, however. If we are flying our plane on Mars, let's assume that that we are kind of draggy with design optimized for delivery and research rather than performance. We'll use a drag coefficient of .75 for ball-park Numbers. A 10 square meter wing has some frontal area as do the other components of our plane. I trust our engineers, but let's not depend on them too much. So for area estimates, let's say we are blunt and draggy. We will pretend we present as much area as a 3m diameter ball of amalgamated airplane parts. If we feed relevant numbers into the drag equation, we can get an idea of thrust required to keep our plane flying at 100m/s.

Styrofoam has a density of roughly 40kg/m^3. Assuming our plane has a wing thickness of 10cm, which is a realistic average, we would have 40kg of foam before we think about motors, structural stuff, instruments, servos etc. So we may be a little optimistic. Still a more realistic wing loading with common wing geometry could easily see a Martian plane flying well below 100m/s or 360kph. Now, can an airplane made from foam and Mylar survive landing on mars at those speeds? Well, a typical light, twin engine recip flies In Earth's atmosphere at 180knots, which is in the same ball park in terms of speed. I can't imagine our foam plane surviving well if it lands on n unprepared Martian surface at that speed. So some sort of creative recovery option needs to be devised, like a net for certain drones, parachute recovery (need a huge parachute) etc. For bigger planes, the math and speeds are the same, but the structural challenge of flying men in foam and Mylar on Mars is tough. Tough, but not insurmountable. Similar loadings for man-carrying aircraft ere used in the construction of the Gossamer albatross. Weight of survival gear, life support etc. complicates things, but this is still doable with great cost and risk.

The Martian atmosphere at the surface is roughly 7mb, .02kg/m^3 with a space height of 11km. For a plane flying 1km above the surface we can simplify our discussion am just use figures for lift and drag for a given wing at this density. A typical plane will have a maximum coefficient of lift of about 1.8 or 2 clean. Alright! So let's feed these values into our formulae and start figuring out what sort of wing area we need to fly 100kg of drone or 1000kg of bigger plane! So, feeding our data into the lift equation, we see that 100kg plane at roughly .4g (Mars) and a wing area of 10m^2 would be able to fly at only 150kph or about 45m/s! Let's compare these values to modern materials before we get too happy, though.

So an airplane on Mars is actually feasible, but it would look and perfor, somewhat differently than ones we see here on earth. Very large wings, very light materials and large diameter propellers would be feasible. We can run some math to get an idea of what our martian airplane will be like. So, first, the Martian speed of sound near the surface is about 240m/s. If we want to sustain flight above the speed of sound, energy and control become a little bit more challenging. So supersonic Martian airplanes probably aren't in the cards for any application that has to work in remote and austere environments (mars.) So we need to design a plane that can fly happily at, say, .85 the speed of sound on Mars. Let's use 200m/s for our effective speed limit for a low altitude flyer on Mars.

There are actually proposals and designs to fly fixed wing aircraft in the Martian atmosphere with current technology. The low density atmosphere requires more speed for flight, but this is offered with extremely low wing loading. https://www.nasa.gov/centers/armstrong/features/mars_airplane.html

They do happen frequently. I am more impressed that the VLA can detect these things from such great distances. And that it was detected from such a great distance.

News from the VLA. Apparently some strange source of radio bursts is detectable from a distant galaxy. The energy st the source must have been impressive. https://www.sciencenews.org/article/gotcha-fast-radio-bursts-home-nabbed?tgt=nr

@WinkAllKerb'' Ack! I'm an idiot! Thanks, Winkallkerb!

Here it is. This popscience article talks about a gas ejector using a tank of stored gas. In reality, I think some of the rocket exhaust is tapped or a separate rocket motor is used as the cavitator on the nose of the torpedo. It looks a lot like your idea. http://www.popsci.com/scitech/article/2004-06/supercavitating-torpedo

This is really cool. I agreee with the other posts here regarding exhaust gas energy. I would like to see what you come up with as you keep working on your idea, though. I seem to remember something similar to this as part of a supercavitating torpedo. Obviously it was designed for different pressures and fluids. Let me see if I can't find what I am looking for.