true 4 seater amphibious pusher plans

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by cgaircrft, Nov 9, 2018.

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  1. Nov 14, 2018 #21

    Wanttaja

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  2. Nov 14, 2018 #22

    spaschke

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    There are some Mods needed to reduce the chance of flutter but they are simple. Balancing the control surfaces would have prevented this incident. The 333 owners have an engineering report with modification recommendations by Martin Holman. To my knowledge, there hasn't been a crash since.
    Most designs have had crashes. Pretty much every certificated design has crashed.

    On another note, I also love the thurston trojan. Similar to the 333. I might have built one of those had I known about them before I got the 333.
     
  3. Jun 13, 2019 #23

    cgaircrft

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    What are everyones thoughts on the Seabear? I found an engineer and he thinks that is a good starting point. Change to one pusher overhead and a tricycle retractable landing gear. Hes working on the balance and such. Just seeing what you all think.
    http://www.seabearaircraft.com/aircraft/
     
    Last edited: Jun 13, 2019
  4. Jun 13, 2019 #24

    spaschke

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    I think it's a great amphib as is. You can't make it a pusher without changing the whole design. the door is in the back.
    The only thing I might want to change is possibly larger engines. I've never flown one so I might be wrong there.
     
  5. Jun 13, 2019 #25

    BBerson

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    Might be an unfinished Air Shark kit out there.
     
  6. Jun 13, 2019 #26

    cgaircrft

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    Its to slow as is. If I increase engines it costs way to much to maintain and fly as a twin. I know the behind cabin will be cut vertical to allow for propeller. We will have a front door and a rear hatch. Tail draggers are not my thing and way more expensive to insure. I know the changes make it a differnt plane in many aspects, but I love the tail design and being able to walk out the back.
     
  7. Jun 13, 2019 #27

    narfi

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    The seabear is a pretty sexy aircraft.
    converting it to a single pusher would be pretty ugly imo, but looks are subjective........

    It seems it would be cheaper to put two mazda rotaries with aluminum housings putting out 200hp each on it than to pay an engineer to design you an uglier plane..... Then once you had flown it a while and wanted to push the power and speed limits think about adding turbos, but you may find you like it just fine as is.
     
  8. Jun 14, 2019 #28

    wsimpso1

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    They appear to have a concept, and $1000 is A LOT for just a three view and some 3D renderings. The vast majority of the engineering work has yet to be done. We are talking several man-months of serious work. Your engine and avionics is little compared to the work to have a design ready to be built.

    Billski
     
  9. Jun 14, 2019 #29

    wsimpso1

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    Have some respect... You are way closer to a napkin sketch than a completed design ready to make tools. Almost all of some serious engineering and drafting effort is ahead of you.

    You really do need to look over a few good sets of plans for existing airplanes, and then understand that none of it is where it is and what it is by accident. The very minimum on anything was experienced eyeballs, with most of it based on careful analysis and design of the joints and features, tracking where everything goes to make sure everything fits, tracking the weight and position of everything to know where the CG is for stability and control, tracking how the whole functions to make sure we will still like the finished project, examining the trade-offs and making choices on lots of stuff, and then iterating the design because some things get out of bed and everything has to be adjusted to make it all work.

    A slick four-seater with everything working, nice to fly, good on the water, durable, and serviceable is a tall order.

    Billski
     
    akwrencher likes this.
  10. Jun 14, 2019 #30

    TFF

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    A friend just bought a Lake Anfib for $60,000. Sounds like a lot of money. I doubt you can scratch build a four seat plane like it for the same amount, and on top of that you have to put the time and effort in too. It has to be all about wanting to build not wanting to use. If you are already dreaming of water spray and your favorite fishing hole, you are on the loosing battle side.
     
  11. Jun 15, 2019 #31

    Tiger Tim

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    Just to be clear, you want to learn to (or already can) fly a seaplane but have decided a little wheel at the back is just too much? Seems to me a Spencer Air Car is what you’re after, maybe with some math done to see if it can handle an automotive V8 like some of the Seabee conversions.
     
  12. Jun 16, 2019 #32

    Riggerrob

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    If you like the looks of the Seabear, check out some of the other light seaplanes destined by Russian Alexa Annenkov.
    An EAA Chapter in Lawrence, MA is building a VAL-31 light amphibian. They posted plenty - on www.homebuiltIrplanes.com - during 2018.
    Search for New Community Amphibian.
     
  13. Jun 17, 2019 #33

    cgaircrft

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    I appreciate the positive helpful comments. I totally understand the undertaking and do not need the lecture. I love the sea bear, but since Id need more power Id have to go with 2-13b's, of which I have, but then at 8 gallons per hour per engine I am now at 16 gallons per hour fuel burn. Thats double the fuel expense I am shooting for. I have 2 engines to maintain and rebuild when needed, I have more expensive insurance by three times to add the tail dragger and the twin engines to the already existing retractable landing gear. I wish there was a nice sleek proven plane that met my needs, I'd buy one tommorrow, but it doesnt exist. I am liscensed to fly a simialar plane and have done so for sometime. I do not need comments from the peanut gallery, so If you are here in a jealous effort to poke fun please move on. To those who are treating me like an adult I appreciate the help and ideas. Thank You.
     
  14. Jun 17, 2019 #34

    cgaircrft

    cgaircrft

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    I searched and found nothing, do you have a link?
     
  15. Jun 17, 2019 #35

    Riggerrob

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    Alex Annenkov has also designed a single-engine flying boat with 3 or 4 seats.
     
  16. Jun 17, 2019 #36

    narfi

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    https://www.homebuiltairplanes.com/...l-31-aquarius-a-non-commercial-project.28991/

    Just to clarify what you are looking for; you basically want the equivalent of a cessna 185 on amphibious floats, but faster and sexier right?
    What is cruise fuel burn on an io520?

    I am not an expert, but I doubt it is reasonable to expect single digit gph for a 4 place aircraft that is also fast. (while dragging a boat hull around)
    Even if you are ok with going slow, you want to make sure you have enough power to break free of the water.....

    I think it comes back to compromises, and which aspects you are willing to compromise on and which are set in stone for your needs.

    budget, weight, power, speed, range, comfort, safety, minimum lake size, etc....
     
    Last edited: Jun 17, 2019
  17. Jun 17, 2019 #37

    BBerson

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    Two engines bolted together doesn't require a twin rating.
    Two engines at reduced power isn't double the fuel consumption.
     
  18. Jun 18, 2019 #38

    akwrencher

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    Rough figures for io520 size engines will be 16+ gal per hour cruise. 206/207 on wheels is around that IIRC. Not sure what the amphibs do to that, maybe not much but slow you down?

    Mind you, that's not at higher alts probably 2000-4000 feet watching the gauges on the air taxi planes around here.
     
  19. Jun 18, 2019 #39

    Riggerrob

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    Guys,
    Please try to stick with the OP's decision to install an automotive Wankel engine in his amphibian.
    I know very little about Wankels, but can share comments overheard when we had all four different engined Republic Seabees at Pitt Meadows Airport: Franklin, Lycoming, Pratt & Whitney and Corvette.

    Republic Seabee is one of the few production amphibians that matches the OP's mission. C.P. Spencer was test pilot at Republic during World War 2. 'Spencer designed three variations on his Aircar, the Republic Seabee and Trident Trigull. Too bad Republic quit making Seabees 70 years ago. It is still regarded as one of the better small flying boats. Perhaps we can learn from Seabee engine options.

    The original Franklin engine rarely produced its rated 215 horsepower, but burned plenty of fuel in the process. The hge cabin was easy to overload, but the original Franklin engine struggled to take off.

    The various Lycoming conversions (435, 480 and 540) improved power and parts availability at the expense of balance problems. Balance problems were so bad that many owners installed truck batteries in the bow for balance. Heavy batteries reduced useful load to only two people.

    The Pratt & Whitney PT6A turboprop engine dramatically increased power ... but also increased fuel dramatically. Extra fuel tanks were installed in the wing roots to improve range. All that extra weight of fuel reduced that one-off Seabee conversion to a two-seater.

    The best engine for a Seabee is the Robinson/Corvette automobile engine conversion. The Corvette engine gets an extended propeller shaft, restoring balance. The Corvette engine produces a up to 350 horsepower and consumes half as much fuel as the Franklin or Lycoming engines. A bonus that the Corvette's liquid-cooling provides cabin heat for the first time.
    www.seabeeinfo.com

    Another option is for the OP to contact Seabee guru Brian Robinson to discuss collaborating on the Robinson Horizon X2 ..... next generration Seabee.
     
    Last edited: Jun 18, 2019
  20. Jun 18, 2019 #40

    cgaircrft

    cgaircrft

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    I have a friend in Idaho that has 13b in his four seat land plane. He is at around 8 gal per hour, that is where I got my fuel consumption data. His plane is around 1400 lbs ready to fly. Mine should be close to that according to my figures. The seabee is a very useful plane, not the most aerodynamic, and weighs in at 2000 lbs. My plane should be lighter and more efficient that the seabee. The Mazda 13b with psru, turbo, radiator, oil cooler and fluids is around 350 lbs, over 100 lbs lighter than a equivalent 300 hp engine. I know alot of these figures are guesses from other data, but they should be close. I am a cabinet maker and have access to a cnc to make all my styro plugs for molds. Solid works talks to mt cnc and I can make everything there. Im excited to get underway yet realize I have alot of things to accomplish. Still wishing there was a real close platform to start with.
     

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