Amphibious Aircraft Challenges

Discussion in 'Bush / Float flying' started by jjbaker, Aug 21, 2010.

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  1. Aug 21, 2010 #1

    jjbaker

    jjbaker

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  2. Oct 27, 2010 #2

    Voyeurger

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    Hey JJ, I've got an Amphibious Aircraft challenge for you.
    I am not a member of your Seaplane Forum, but I would like you to help me get an ID on a small duck that someone else posted here. If you could please start a new topic in your other Forum with this photo, I'll bet one of those duck drivers can ID it. Oh, one more thing. I'll be driving through Bangor on Thursday next (Nov. 4th), to pack up an Amphib Kit that I bought at auction. The aircraft is a Falconar Teal. There's pictures in my album on my profile page. The duck is located north of Bangor in Old Town. Guy worked on it for 20 years, then passed away. Poor guy got it about 80% done. I bought it from EAA Chapter 827 in Newburgh. I've got to figure out some way of packing it for truck shipment back to California, then pack it, then load it so it receives not so much as a scratch on the long journey. If you want to check out this man's wonderful work and see a rare seaplane, you're more then welcome to tag along with my wife and I. We're staying up there (somewhere) until Monday Nov. 8th.
    I have attached the photo I mentioned before I started rambling. If you could post it I'd appreciate it. It looks a like like a four seat Sikorsky S-39, but I think it's home built. If you enter Sikorsky S-39 in this Forum's Search field you can find the message trying to ID it and watch the short video.
    Let me know if you want to go "play" on Thursday, Friday, or Saturday.
    Thanks!
    Gary
    [​IMG]
     
  3. Oct 27, 2010 #3

    jjbaker

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  4. Oct 27, 2010 #4

    autoreply

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    No, thanks, another forum to apply for? This one is already too small for many questions. VAF is the only one I can think of with sufficient size to discuss the broad amount of general topics and also have enough specific knowledge. Not meant to be offensive, but there is a "critical mass" below which a forum usually quickly "turns into itself".

    Well, so far my ranting ;)

    Now my challenge :gig:

    Why isn't there a flying, amphibian RV/camper/sailing yacht? (Camper is just the European designation of a small rv).

    I'm thinking, something along the lines of how a sailing yacht is used. Small toilet, maybe a douche, sleeping for 4 people and able to take maybe 5/6 aboard, primitive, but roomy enough to move around. Small kitchen, camping-like and so on.

    Cruise around in the Caribbeans, a weekend trip, hopping by a river and so on. Pause in a harbor, or an airfield.

    That requires quite a bit of cabinload (1500 lbs or so, if you take the toilet, douche, kitchen into account). Even more challenging though, it takes a lot of internal volume.

    I'm thinking of a combination of the Catalina layout and the Dean Wilson approach to a fuselage. Sponsons (with RG gear, fuel and a swimming step), huge fuselage. Huge like, the dimensions of a 20 ft container (8X8X20) for the internal dimensions. Parasol wing, push-pull nacelle on top of the wing. 2X200 HP seems achievable, given the very low speeds and efficient wing.

    No struts, cables or whatsoever. Composite finishing. High aspect ratio plane. Very low stall/approach speed (C-152-like), let's say, 40 kts stall, 60 approach, 120 cruise. That keeps cost reasonable, and it also stays a STOL-vehicle.

    Nobody did something alike though, except for Dean Wilsons lonely aircraft. The Dornier Seastar comes close, but the cabin is quite small. Ow, and it's engines are the cost of a new Mooney/Bonanza.

    Any thoughts why such a concept wouldn't be feasible?
     
  5. Oct 28, 2010 #5

    skeeter_ca

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    Airplanes and internal volume only come hand in hand with big dollars. Grumman Albatross's are converted sometimes to a nice flying RV, at a price tag of about $1,000,000.00.
     
  6. Oct 28, 2010 #6

    autoreply

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    I think that doesn't have to do much with internal volume. Engine power (gheez, those engines are expensive to maintain), complex instruments and such come to mind for the Albatross. Not to speak of the fuel burn of 3000 HP! Far-25 certification and the accompanying insurance, maintenance and conversion cost doesn't really make one happy either does it?

    That's not very relevant for a 2-3 tonne, light amphibian, compared to a 17 ton, commercial air transport.

    I don't see a reason why such a light flying boat should be any more expensive to operate as a comparable twin, say a normally aspirated Seneca?
     
  7. Oct 28, 2010 #7

    PTAirco

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    I have been doodling with such a design for 20 years. Always have been torn between boats and airplanes and why not combine the two? Easier said than done, that is why. My idea ended up a huge twin engined amphibian along the lines of the Grumman Goose. Good sense has shrunk it since then a little, but the shape is still there. Composites naturally; if ever there was a case to be made for foam and glass, the amphibian is it. Ideally I want a pair of rebuilt 270 hp Guiberson Diesel radials, so I can actually afford to fly it. (And fly down to fill up in Venezuela at 10 cents a gallon..)

    40 ft span, sleeps two in saloon, small galley, bathroom (head) at the very rear with sit down shower. There is stand-up headroom just behind the cockpit area, where the galley is located. A few different interior layouts are possible. Structurally very simple; since it would be a one-off, mostly built the Rutan way. Wet wings and huge tanks in the nacelles.

    With some overload of fuel, California to Hawaii is possible, even if takes 20 hours at economical cruise. (Hey, you can stretch out, take a nap, make a three course dinner, watch movies - who cares how long it takes?)
    For when at rest, pop-up wind generator and solar panels to power things. Small retractable (Diesel?) outboard in well to power around while mooring etc. Generally equipped with all the goodies that make yacht life comfortable. I need more time on this planet to get it finished though.
     

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  8. Oct 28, 2010 #8

    Topaz

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    Something I've often considered in this vein is that you really don't need the usable volume until you're on the ground/water. For a light-weight/small "aerial RV", amphibious or not, a "pop up" aft fuselage section (as in the pop-up camping trailers, with a hard roof and fabric sides) would go a long way towards keeping the aircraft small and light overall, but with a lot of usable volume as a camper. The weight penalty for the pop-up roof ought to be fairly small.

    If the fuselage is wide but relatively flat when the "top" is collapsed, you'd still have a large floor space. I see no reason why the walls of the bathroom/shower and any other living-space divisions can't be canvas or some other opaque fabric instead of solid structure, and simply extend upward with the top. It's acceptable for large, multi-person tent, so it ought to be acceptable in this application.
     
  9. Oct 28, 2010 #9

    autoreply

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    I beg to differ. Let's assume, 4000 lbs empty (including toilet and such), 11 gallons/hour. That's 135 lbs/hour. 3 hours of fuel and 6 pob adds up to 1450 lbs useful. Alternatively, that's 2 pob and a good 8 hours of fuel. So let's assume we're 6000 lbs MTOW (which gives us an extra 4 hours of flight in both scenarios)
    Wing loading has to be really low. Something around a C-172 sounds right. 75 kg/m2, or 17 lbs/sqft seems ok. That's about 352 sqft. A span of 40 ft gives you an aspect ratio of just over 4.5 That's way too low since low speed drag (induced drag thus) is the most important issue on such a craft.

    Let's look at an aspect ratio of 10, which gives a span of 60 ft. That's much better, especially if we can fly (climb) at 60-70 kts. Induced drag now is so low that you can get away with only 180 HP (and still climb), if the other engine quits.

    I've given it a fair amount of thought. A major issue is C of G, especially with high fuel loads in the wing, up there. If the engines are above the wing (necessary for spray/noise), it's even worse. Sponsons are ideal. Put the fuel in them, put the landing gear in them (when folded, it's above the water, so it doesn't wear/rust), use it as an entrance/diving platform, no fuzzing with tip floats, ow, and another point Topaz made.

    I thought about it quite a lot. (Which is nothing more than dreams, because over here it's impossible and it's far out of my budget for the coming years).

    A couple of things you really need:

    * Toilets. The wife is also present.
    * A kitchen. Extremely simple is just fine.
    * Extremely low noise levels (thick, isolated roof, low rpm props and such) This is actually one of the hardest parts.
    * An outboard motor. Easy manoeuvrings is extremely important in a harbor. 2 hp is plenty.
    * Wheels.

    This is one of those occasions where you're so into a particular subject (aviation) that you don't see the alternatives. Despite being on campings with everything from a full-scale RV to a tiny walking tent for years...


    So, great suggestion. I do see several problems, but none of them can't be solved (with serious penalties). They're mostly structural, especially when you have a roof that pops up, you'll have a problem with the bending load, that's pretty severe in a waterplane.

    So pop-out to the side (as in many RV's) might be ideal, especially, if using sponsons:
    [​IMG]
    I'm proposing this layout, but with the engines on top of the fuselage (push-pull, because of noise).

    Imagine you have those sponsons. Imagine a fuselage that's 5X5X15' internal, with rounded edges. A large sitting room, kitchen, minimal douche and lavatory in the back is enough. In the nose, in front of the feet of the pilot, there's a small "masters bedroom". Now, given that a sponson has a span (from the fuselage out) of something like 3', you can either have a fabric "tent", or a plastic, sliding unit, that extends from the center of the aircraft.

    Very interesting ideas :)
     
  10. Oct 28, 2010 #10

    Dana

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    Wilson's aircraft are really neat.. it'd be great if somebody took up where he left off:

    [​IMG]

    [​IMG]

    OTOH, I remember reading in Flying magazine some 30 years about about a PBY converted into a flying RV, picture couches in the gun blisters... if you can afford to fill the 2000 gallon fuel tanks...

    Re flying around in the Caribbean, read Jimmy Buffett's book... he flew around the islands in an Albatross and had all kinds of problems getting permission to land on the water in manay countries.

    -Dana

    But it's NOT an ASSAULT Weapon, it's a DEFENSE weapon!
     
  11. Oct 28, 2010 #11

    Voyeurger

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    Why isn't there a flying, amphibian RV/camper/sailing yacht? (Camper is just the European designation of a small rv).

    Hey Auto,
    You DO realize "douche" does not necessarily mean shower on this side of the pond, right?:para:
    Like the idea though. Could it be time for the "Led Zeppelin" forum?
     
  12. Oct 28, 2010 #12

    MadRocketScientist

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    If I could get hold of drawings for Dean Wilson's Global Explorer.... I would really like to build one.;);):)

    We have a Catalina here in NZ that is available for charter if you have deep enough pockets.

    Shannon.

    Shannon.
     
  13. Oct 28, 2010 #13

    Voyeurger

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    Bear with me here guys. I'm sure you are all familiar with the Volkswagen Pop-Top camper vans. Hang some big wings (folders) on it, a long (bolt on) empennage for elevator and rudder, and drive it with a pulley/ belt off the engine. Haven't figured out the water arrangement yet.
     
  14. Oct 28, 2010 #14

    jjbaker

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    Haha! Too funny! Critical mass? Another forum to join?
    No offense taken. Everything starts somewhere.
    Back to trying to translate what you could have meant with a douche, and stuff. ;)
     
  15. Oct 28, 2010 #15

    Voyeurger

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    If you "Old Salts (old SMART salts)" prefer, ask the moderator to create a sandbox forum for those of us who make up for our lack of knowledge with an overabundance of enthusiasm. We'd be happy there, and wouldn't interrupt so much here, AND, we could fire one off here every once and a while, but only when we all agree it's worthwhile.:gig:
     
  16. Oct 28, 2010 #16

    autoreply

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    I did know "douchebag" wasn't the most complimentary way to speak to someone. Now I know the other meaning as well :speechles

    Well, I think you misunderstood me. I'd rather have all posters and replies on a single forum, but that's just me. A larger group and some more enthusiastic people are better for both groups I guess ;)
    Yeah, I guess that's the reason amphibs aren't used that much for these kind of journeys. With a retractable LG though, you can overcome many of these troubles, though it takes away part of the "freedom" behind it.
    And well, within the US, Canada and Alaska you probably don't have that much trouble with it.

    Here in Europe it's even worse, it's virtually impossible to operate a amphibious aircraft, despite the fact that we're one of the most suitable countries in the world for it. It's a pitty, but I'm realistic enough to see that - except for Africa/South America - such a craft will be quite limited in it's abilities.
     
  17. Oct 28, 2010 #17

    Dana

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    Well, the Short Skyvan was originally designed to carry wheeled vehicles of the VW Microbus size, just drive it up the rear ramp and off you go... 'course it's not amphibious...

    [​IMG]

    -Dana

    "A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." -Antoine de Saint-Exupery
     
  18. Oct 28, 2010 #18

    PTAirco

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    But all the Skyvan needs is a big lump of foam glued to the bottom, carved into a hull shape and glassed over - instant flying boat!.
     
  19. Oct 29, 2010 #19

    jjbaker

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    I hear the word "sandbox" may cause allergic reactions.
    So far we have determined that your picture looks like some sort of ugly car, with a strange wing glued on top of it.
     
  20. Oct 29, 2010 #20

    jhausch

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    This one has always looked interesting to me. I recall some pictures with 6 seats and sliding doors. Figure out how to lay the seats down into beds and you have the equivalent of a cuddy cabin to dock at the marina.

    Centaur Seaplane plc. - Home
     

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