Small ship-based UAS

[mokimakana]

Hello all-

I work for NOAA, the National Oceanic and Atmospheric Administration, the US gov't agency that does (among other things) research on living marine resources (i.e. fish, seals, etc.) and oceanography.

I'm trying to talk NOAA into letting me work on UASs for them. We have a small UAS presence currently, but it seems mostly focused on large, *very* expensive, medium to high altitude, long endurance atmospheric research (we're sharing a Predator knock off (I think) with NASA). I work on one of NOAA's ships, and have seen the need for a much smaller, much much cheaper, ship-deployable and retrievable UAS. NOAA's made a few stabs in this direction, but with nothing too concrete (yet). Hopefully the powers that be will see the light and let me spend some time and dollars to get a system off the deck (I drive ships for a living but R/C planes for fun--so hopefully I can be the guy to integrate ships and UASs).

I'm envisioning a fuel-powered UAS capable of transmitting real time video on at least two channels (one downward looking, data-gathering, one fwd looking for the pilot) capable of flying a pre-programmed route and being piloted to investigate items of interest en-route. Almost certainly a fixed-wing aircraft--VTOL and rotocraft UAS seem too complicated to meet my 'relatively cheap' goal.

Here's my question, and I'm not sure if I'm better off here or in the FPV thread, but I'll take a stab at it here. How do we get the thing back on the ship in one piece??? I've been giving it some thought and I see basically three option, each with some limitations. To get a UAS back on one of our ships we could:

1. Manually pilot it onto a landing area. The limitation here is that our ship are pretty small--the landing area would be ~40'by 40'. Obviously there would have to be a net (or some other arresting system?) I've rigged up an R/C plane simulator (Realflight) with a similar sized landing area, and I can get a plane on there pretty reliable when I put myself 'in' the cockpit (like having an FPV camera). But it seems like doing it in the real world might be harder than in RealFlight. Plus building a flight deck for a ship is an endevour. However, this requires the most piloting skill, so I'd have to spend lots of time at work practicing :D

2. Land on the water. The drawback here is you are limited by conditions (too windy=no landing area), but you probably don't want to fly in those conditions anyways. The bigger drawback I see is that you have lots of sensitive electronics and camera's which don't play well with salt water. Can the UAS be made waterproof enough to operate for the long term in the marine environment doing water landings?

3. Insitu's sky hook/scan eagle. This would work great, but I'm not sure I want to limit myself to one vendor--I'd like to be able to consider other options.

I've know the US Navy used to land small UAS on flight decks, not sure if they still do. I also don't know the details on how the landing is done (a FPV system?) or the size of their landing areas. Anybody got any insight?

Anybody have anythoughts on how to reliably get a UAS back on to a ship?

Thanks.

[hg1]

Do you have specs for your UAS, i.e. wingspan, max speed, max altitude, range / flight time, minimal weather conditions, etc ?

[mokimakana]

Hi hg1-

Nothing too concrete yet. I'm envisioning a wing span in the 3 meter range-too much bigger and it won't fit on the ship! The ability to land on or near the ship in winds up to 20 knots would be good--otherwise it will never be calm enough to fly. Beyond that, there are no concrete requirements, though I'd imagine those two will end up constraining most of the other parameters. Off the top of my head, I'd say a max speed of 50 kts, an endurance of 8 hours, so thats a range of 400 nm. More is always better, of course! Max altitude--I'm envisioning using it for ice seal surveys, so thats a fairly low altitude, but for other apps I could see ~1,000 to 2,000 ft above MSL.

The two constraints I see are the 3m wingspan and landing in up to 20 kts. The rest are pretty flexible.

Thanks
Bill

[hg1]

That's very helpful. The aircraft you are describing is outside of my range of experience, but I expect that there are others on this forum who can give you some concrete suggestions.

[macboffin]

The biggest problem I see is a three meter plane with 8 hours of fuel aboard, thats a tall order, especially with cameras etc. Battery weight alone could be significant, although the best answer for serious duration is an on-board generator, engine driven, plenty around. Ice seals implies ice, therefore low temps, another source of problems. You would also need some serious power, on account of wind : if your cruise speed is sixty and you are bucking a thirty knot head wind it takes longer to come home and burns a lot of fuel. I think that landing on water with a plane that small in open sea is not on except on a very calm day. The Insitu recovery method of catching a vertical line with a wing-tip hook is the best system ; requires a swept back wing, or a flying wing layout, so the line slides into the hook, ( as long as it misses the prop!).Landing onto deck areas is very difficult on account of turbulence generated by the ship itself. Proofing against the marine environment is the least problem. It also pays not to have too low a wing loading, ; twice the weight only adds 25% to stall speed, but a heavier plane has better penetration in turbulence, this would be especially important during recovery. A three meter span implies maybe twelve to fifteen feet of area, so an all up wight of forty five/fifty pounds would be ok. Regarding marine environment, max use of plastics,(epoxy glass/kevlar etc) and minimum use of ali or wood in construction is indicated. It's certainly do-able.
Macboffin.

[mokimakana]

Thanks macboffin-

the 8-hr endurance was pretty much a stab in the dark, there's a fair amount of flexibility there, though obviously more is always better! Ship turbulence shouldn't be too much of a problem in this case, as the ship can be stopped, and abeam to the wind for recovery, providing relatively little/no ship air wake turbulence. Still, getting a 3 M wingspan plane on a 40' x 40' deck seems challenging (but maybe fun!).

Ice is another big issue. I've read up a bit in some other threads on cold weather ops. Using waste engine heat has always seemed like an obvious answer to me, but it does add complexity. That's cabin heat. Icing is another big unknown. I know that there have been people operating UASs out of Barrow, AK sucessfully, I think using some sort of sacrifical anti-icing coating on the wings--does that make any sense?

Perhaps I should just pack it all in and work on a project in Hawaii instead :D

Regarding plastics, epoxies, etc. for the marine environment-yes yes yes. I'm more concerned about sensative, critical electronics than strucutural corrosion. Even with a well-waterproofed central compartment for electronics, you still have a variety of electronic things outside--servo's, sensors, etc., to say nothing of the 'payload' electronics-camera's etc. All that makes water landings scary in my book.

Thanks for the input.

[hg1]

This is a bit off-the-wall, but it might be worth researching fuel cell power as an alternative to an onboard generator, as the energy density of the fuel is quite good. Take a look at the H-100 and H-200 PEM fuel cell systems here - http://www.horizonfuelcell.com/file/H-Series.pdf

Depending on the aircraft, a 20L storage canister might yield 10-20 minutes of flight, and 3 canisters weigh 1lb.

Ballpark, what size BL motor is required to power an aircraft that weighs 10-12lbs ?

[mokimakana]

Regarding water landings, there's at least one system out there that can land in 25 kts and some chop--though I'd like to see it in 25 kts that have been blowing steadily in the Bering Sea with unlimited fetch, yielding 11 ft seas :)

But check out: http://www.centaurseaplane.com/gull/index.htm

[Unterhausen]

Or you could just crash land it into your dining room like this guy:
http://www.metacafe.com/watch/803395/rpv_fpv_na_varanda/

[lvspark]

I'd get a quote from Insitu on one of their seascan units...

[macboffin]

I'd get a quote from Insitu on one of their seascan units... When the quote arrives, sit down, take a tranquilliser or two, then see what the price is!

[lvspark]

:D

Maybe a little spendy out of the box, but small, long endurance, stable camera, proven, cloudcap nav, many hrs experience in cold weather (aerosonde), and has the hook!

No longer on thier site, but the ship based nightime autonomous skyhook recovery video was very nice..
http://msnbcmedia4.msn.com/j/msnbc/Components/Photos/040511/040511_cosmiclog_bcol2_12p.standard.jpg

[mokimakana]

Hmm, tranquilizers--I've been waiting for an excuse to get the medical officer to break out some of the 'good stuff' they keep in the safe :D

Insitu does seem like an obvious answer, I'd just like to consider all available/ concievable options. Gotta make sure those taxpayers are getting the most pow for their peso.

Hg1, thanks for the fuel cell link--we'll need longer flight times than an all-electric vehicle will bring, but that might be a great way to power all the onboard electronics!

lsvpark--I didn't realize that aerosonde (the ice people) and insitu (the fly-it-into-a-boat people) were the same-is that true?? That certainly is a powerful mix of capabilites, from my point of view. I also admire their taste in marine test platforms--I use to drive a cute little wooden boat around Puget Sound too...

[chrisgood]

Insitu and Aerosonde worked together for a long time, and did accomplish the Insitu-Aerosonde Laima flight across the North Atlantic in 1998. However, they have not worked closely in several years. Aerosonde was purchased by AAI in 2006, and Insitu has been teamed with Boeing since 2003. The group of people who made the avionics for the original Aerosonde aircraft split off themselves to form Cloud Cap Technology.

I got to visit Aerosonde in Australia in August for a business trip. It was neat to see and hold an original Laima wing set. Aerosonde and AAI are now working to further develop UAVs of this type.

Chris

[lvspark]

Nice pictures on your trip Chris.. So now that we have you here, you know whats out there.. Value vs performance vs ship based.. Aerosonde ? Seascan? Neptune?

[N2EC]

You could also look at DRS Technolgies - Neptune UAV

[mokimakana]

Hmmm, I looked at the Neptune several months ago, I'll have to take another look. Water landings + electronics are scary, but I guess a few fried components is better than smacking into the side of the ship...

I'd be interested in know generally how de-icing was accomplished. Anybody have any insights?

Thanks
Bill

[lvspark]

I don't think they de-iced Aerosonde, it just did not amount to much.. I'll look for the links...


EDIT: About my above statement, they did loose 2 due to ice but then installed ice sensors things went better...
http://www.aerosonde.com/drawarticle/35#Field_Reports
http://curry.eas.gatech.edu/currydoc/Curry_BAMS85A.pdf

http://www.aerosonde.com/images/upload/1482248655_b2002_justin_640.jpg

[kd7ost]

Nice find Mike.

Dan

[macboffin]

Very interesting and illustrative picture.

[mokimakana]

Wow, nice. Our air temps at sea level during the ice surveys are mostly above 0 deg C, but I'd imagine at altitude icing might become an issue quickly. Fortunately we had several days like this:

[chrisgood]

I am probably a bit biased. I am the lead avionics engineer for Shadow with AAI, (who owns Aerosonde) and am one of the AAI engineers working with Aerosonde on their planes. Who do you think I am going to recommend?

Aerosonde has proven over and over that they can handle sea conditions. The Laima that flew across the North Atlantic in 1998 was estimated to have flown through rain for over 14 hours. No matter how well an aircraft is sealed against the weather, water will get in if it is flying in rain that long. There was an inch of rain water in the belly of that plane when it landed in Scotland after the flight.

Chris

Nice pictures on your trip Chris.. So now that we have you here, you know whats out there.. Value vs performance vs ship based.. Aerosonde ? Seascan? Neptune?

[lvspark]

heh heh I understand..
What about shipboard operations? Does Aerosonde have a recovery system other than belly landing?

[chrisgood]

I can't really comment on capabilities that may or may not be under development.

I can link to a video of another AAI plane, the Shadow 400, which weighs 465 pounds fueled, flying into a net on the back of a ship.

http://www.aaicorp.com/New/UAS/assets/multimedia/Shadow_400.mov

I can also say that Pioneer, a joint development UAV between AAI and IAI, has been doing that same kind of net recovery for almost 20 years.

Chris

[mokimakana]

Hello all and thanks for your info. I've been stuck behind the Pribilof Islands, waiting out a storm, without internet for two days (oh, the humanity!).

A question about auto-landings (either net or into a wire)--I assume these are based on DGPS signals (right?). Our differential signal is weak to non-existent in the Bering Sea (not sure about the Northwest Hawaiian Islands, the other potential test site)--is there another way to tell the UAS where to land? Or will I have to fly the thing onto the deck?

Thanks.

Bill

[Michael_UAV]

http://uas.noaa.gov/projects/demos/silverfox/

http://uas.noaa.gov/projects/demos/manta/