Some companies, businesses and entities, employing, (or considering the development and deployment of), muti-rotor drones for surveillance and monitoring critical operations, etc ... cannot, or will not be able to simply ground their multi-rotor drone fleets during rain and rainy weather conditions, (not storms). The show must go on. It is implausible to suggest to a potential client, or project endeavoring to use multi-rotor drones that they have a secondary or back up system in place to function during rain and semi-inclement weather, such as a legacy system that duplicates what a fleet of drones might accomplish.
We can foresee a proven, tested, ArduCopter design where the software and hardware are specifically tweaked and modified to create a drone that flies well in rain and semi-gusty, raining conditions, (and of course is completely water tight). In regions of our planet where this type of design will be required for significant portions of the year, this type of design will be a big winner in those markets and will dominate sales in those regions. In some regions, those purchasing multi-rotor drones will consider no drone, except those that are marketed as "rain drones", if they become available. Perhaps one day, the "rain drone" will be the standard design.
Designing or adding the necessary component modifications to make a drone that can fly at 20+ MPH in rain and maintain absolute, total, water tight integrity is a significant task. Perhaps like the AquaCopter designs, that type of design should be from scratch. Being in an area where it rains consistently, (an equatorial, or tropical region), where a drone like this can be tested, documented and proven, is a resource issue as well.
I've seen the AquaCopter designs, (and I think they are ... AWESOME), and I understand that ArduCopter frame and component designs can certainly be made and be modified so that a significantly advanced multi-rotor drone can fly in rain, (not thunderstorms or hurricanes of course), but those that can fly, and fly well, in the typical and persistent tropical rains during the rainy seasons in many equatorial and tropical areas ... (that perpetual drizzle) ... and high humidity that lasts, for example in Nicaragua, for 6 months out of the year.
And of course there are snowy climes, where the snow accumulates on the copter, and can melt due to heat dissipation by components. And the rapid ascent of a copter to a high altitude causing condensation on the copter's hotpoints, well, moisture is an issue, but creating a copter specifically designed for continual "rain duty", that's a nice kettle of fish. And there's more.
Let's take for example, just for the sake of discussion and a limiting of environmental variables, (for a discussion framework), let's use Nicaragua as our geographic test area. Nicaragua has a significant amount of interior, it has some mountain range, (and mountainous areas). Nicaragua has some really way cool and radical volcanoes that blow up regularly. Wind speeds in Nicaragua are generally consistent and below 10 knots on average, (and significantly lower during many months of the rainy season at sea level, (and just above sea level), in the flatter, lower, jungle canopy areas), and wind speeds in Nicaragua do not increase substantially when you move east or west towards Nicaragua's Pacific or Atlantic coasts. Nicaragua is very "wind consistent" across the greatest portions of its area.
As well, wind speeds in Nicaragua tend to be very consistent and lack a gusty quality in much of the interior due to the semi-dense canopy of trees that carpet most of the interior and along the coastal areas. Vast sheets of wind scrape along the Nicaraguan jungle canopies and are tamed to a great extent, are made uniform, forming large areas of wind activity that are consistent in speed and direction. So when this semi-annual rainy season occurs, wind speeds, (thus rain speeds and rain densities and variability), are of a nature that is more consistent for testing and data collection, thus the testing of "Rain Copter" designs and systems is much more available, consistent and long term in a place like Nicaragua.
"Rain Copter" design is of course significant in many industries, like agriculture. Copters that serve agricultural needs are going to be exposed to significant rain, water and moisture. Any long term, solar powered copter solution with significant range and flight time, and even the advent of mid-air "refueled" copters, (mid-air battery swap), those copter designs are going to face significant rain issues as well.
So, must of us understand that creating such an ArduCopter can be done, sure, it's some work, it takes some money, and they might be more expensive, but by and large, I think we can all agree this can be done, and done well, (over time), by almost any of the lead developers that are members here. Most importantly, this site serves as a crowd source and information, idea and implementation nexus which is far more powerful than any corporate effort throwing money into a project. Thank you all for being here and making this resource and this community a reality, see, you need a tissue now, don't cry on that copter buddy! ;-)
My concern, the "trick", is having this copter take high quality video, and employs imaging devices during these long term rainy seasons which occur over significant parts of our planet. It's not just about a water tight container for the imaging system. The camera eye, or lens, must of course be inside some type of protective, transparent enclosure. And if the camera lens itself is water rated, water tight, it's not like the lens would be underwater with a perfect film of water covering the lens aperture, (the front glass).
And this solution should attempt to utilize resources that are more affordable, and available to the hobby and general enthusiast. Sure, NASA, the military, they have designs that deal with this type of solution, but they aren't perfect, by any means. And often, even the most advanced drone systems of all, get "Image Washed", or "Rained Out".
Drops of rain that splatter on the surface of the transparent enclosure housing the camera, (or a water rated lens), are going to cause significant aberrations in the quality of the video capture and still image capture, (or simply make it completely untenable). On YouTube we see a video shot through the windshield of a car, the wipers going, it's raining, it's driving us NUTS. So sure, windshield wipers, or some type of modified windshield wiper design, might work, in some capacity.
I am of the thinking that a "Rain Copter" design must be outfitted with an imaging solution that inhibits greatly, or totally negates the effects of the rain drops that will interfere with image quality. In my thinking, the only plausible starting point for a long term "Rain Duty" copter is to FIRST design this "imaging gear" housing that provides for clear, unobstructed and transparent imaging during flight ... in the rain. If you want to see what your copter is doing in the rain, or if you want to produce high quality video or still images in the rain, you must have this "rain imaging" system in place on the "rain copter".
I have an inkling of an idea, a globe that the camera is inside, a water tight, lightweight, transparent globe that spins very, very rapidly. A very light, water tight globe, that uses centrifugal force as it spins rapidly, to throw the rain off of the globe, the imaging device(s) then film(s) through the transparent globe. There are probably some modifications that can be made to that globe, through the application of "water droplet cohesion" and "water droplet behavior" sciences, that could make this spinning globe, or moving globe quite efficient as it provides a window of clear view for the imaging solution inside. So the globe might be created, cast, or 3D printed, so that there are slight grooves, or rivulets in the globe, undulations in the surface of the globe that are created to assist in both driving rain off the globe and channeling the rain so that it can be more efficiently driven off the globe and also maintain an area of complete water sheet perhaps, around the exterior surface of the globe. And you might end up with a solution that has a bit of interfering water, and that sucks, its not perfect, but it would be a great start.
Another idea I have, is the spinning globe outfitted with a FIXED wiper blade, (that continuously wipes the rain off the rapidly spinning globe), and the blade is positioned just to the extreme of the lens' field of vision, so that an area on the surface of the globe is then as moisture free, droplet free as possible. That blade is also a gutter, where the wiped water travels DOWN the length of the blade and issues away from the globe, under the copter. That area of the "wiped globe", is just in front of the lens of the imaging system. The "rain copter imaging globe" might even have a sheet of rain, transparent over that area of the globe maintained, (in heavier or denser rain), so that a super thin sheet of rain created by the static wiper, then becomes a PART of the transparent structure of the globe, and maybe that's pie, but it's grist as well.
And then some of us are probably familiar with the design and concept design of a globe within a globe, (nested, articulating globe housings), where the camera has limited movement and mostly points down, and where the external globe opens just enough for imaging to proceed, but, the internal globe is shrouded or protected by the external globe, just musing at this point to perhaps spark some discussion on design concept.
Any ideas, links, information, insight, just anything discussed that could go towards finding some type of solution for a rain copter's imaging systems, so that it could function efficiently in "regular and extended, long term rain duty", would be of great interest and greatly appreciated, and thanks to all of the people who are making this site possible, exciting and full of wonder. I'm a newbie here and I've been thinking a lot about business applications for copter and copter fleets in many different contexts, that's where my head is although I love the tech and the code as well.
There is also a passive rain dispersion filter:
In the film business a "captain's glass" is used in front of the lens when shooting scenes where water may get on the lens. It is a flat glass disc that spins, the water droplets are flung off the perimeter of the disc from the centrifugal force. I think this will be a better solution than a globe that spins. A flat plate is easier to make optically correct than a globe.
For the GoPro in the waterproof case, a spinning, dual blade wiper, the wipers made of transparent material, more like scrapers than wipers perhaps ... the blades mounted inside a transparent hub, the hub held at three points by plastic gears on the exterior edge of the hub, the hub spinning rapidly, so rapid, the camera is unable to capture any aberration from the blades.