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 9, 2018 #1

    cgaircrft

    cgaircrft

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    Me and my partner are looking for plans for a amphibious four seat airplane. We have a motor, reduction unit, and all reduntant electronics. The motor is a Mazda 13b 6 port turbo, capable of just over 300 hp. Want a high wing pusher. Looking for any plans to use as a starter point. Please let me know if you need more info or have suggestions. similar to bb airplanes mk4

    https://bbairplanes.com/skycruiser-mk4.html
     
  2. Nov 9, 2018 #2

    BBerson

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  3. Nov 9, 2018 #3

    narfi

    narfi

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    True 4 = 6 right?


    Get a mate for your engine and put them in one of these,
    https://www.gweduck.com/index.html

    or add a rotor and boost it some more and stick it in one of these,
    www.privateerindustries.com

    I think I read somewhere that you can still find a unfinished kit for one of these if you search around hard enough,
    https://www.seawind.net/specs.html

    I really like the look of these,
    http://www.seabearaircraft.com/news/the-new-l-72-6-seater-amphibian/
    I dont know if they offer kits though, I think they are building them all inhouse. There is a guy here on this forum though that is working on a program for building a homebuilt single engine version, you might check his ideas out.
     
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  4. Nov 9, 2018 #4

    lr27

    lr27

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  5. Nov 10, 2018 #5

    cgaircrft

    cgaircrft

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    Thank you for the input. We are looking for something much smaller and sleeker than those mentioned. Like an expanded searey with more hp, faster flight speed, yet stiil good economy. I know its a tough one. BB will sell me their plans but its only been on solidworks not built and no structural building design has been done. They want $1000 seems steep for whats done. Any input to whom might help with the structurals if we went that way?
     
  6. Nov 10, 2018 #6

    lr27

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    To my eye, the S-12-D looks fairly sleek, and it's a good match for a 300 hp engine. i don't know how small you can get a true 4 place amphibian.

    The BB Mk 4 sets off my BS detector. Sleek is in the eye of the beholder, but I gotta say it doesn't look very sleek to me! I question the empty vs. gross weight and the anorexic shroud on the prop which seems to have very little support.
     
  7. Nov 10, 2018 #7

    Chris In Marshfield

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    If you choose the Spencer, your first hurdle is going to be the acquisition of plans. Getting ahold of the Kerans’ is a difficult proposition, no matter how often the surviving Kerans boy will tell you that they’re there. He only comes out of the woodwork when someone says something negative about the plane, then he goes back under his rock.

    Part two, it’s a ridiculously complex airplane with no prefab parts available to purchase. The canopy is a heck of a job to complete, as are the sponsons with integrated fuel tanks. The shortest time I’m aware of to complete that plane has been a bit over ten years. Ya gotta really want it.

    Third, it was designed and drawn by a classic draftsman. It’s not a modern 3D type thing, so you have to be able to visualize from lofting diagrams for the hull. It’s an interesting mental exercise, though. I enjoyed trying to figure it out when I first reviewed them.

    300hp 13b on it? I don’t think so, but my practical experience with Mazdas is zero. Seems like a stretch when anyone claims to get 1000hp out of a Cox .049. 20b, probably a better choice. It was designed for a Continental Tiara which is a much larger, heavier engine (of course). The wings of the -D are swept a bit to accommodate the heavier engine and CG that goes with it. No idea how a much lighter rotary of any flavor would affect that, though. But I think a 20b would be a cool engine to try on it.

    I was able to get plans when Robert Kerans was still alive, so I consider myself lucky. Might try to build it one day, but for now it’s in the archives.
     
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  8. Nov 10, 2018 #8

    narfi

    narfi

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    I like to get excited about a lot of things, I do not see myself as a pessimist.
    I set high goals for myself and if I do not meet them I grin and am proud of what I did do and continue to strive for higher goals without getting down about it.

    That being said, I also have to be a realist.....
    That BB site is 7yrs old, everything is 100% rendered images and hype with no prototype or progress on any physical aspect of advancement, no parts, no molds, no warehouse, no foam model in his moms basement, etc.... ZERO....
    If I had an engine already with time and interest in starting a plane, this wouldn't even register as a possibility to me, even though it does look very nice :(

    300hp, you are looking for any experimental designed for the io540 or io520/550.

    You said a true 4 place, lets define that more, what do you mean?
    For me a true place = 1x 200lb person and 50lbs of gear.(this only personaly gives me 10lbs of gear) So true 4 place = 1k lbs of people and bags + fuel = roughly 1500lbs useful.
    Look at a brand new bonanza, 1140 useful.... its supposed to be 6 place..... with 0 fuel that allows for 6x 190lb people = a 'true 4 place plane'

    Now if you define a 'true 4 place plane' as 2 small adults and 2 kids under 12yrs old with just 1hr of fuel..... then that changes a lot...... then you only need 600 useful...... less than half the plane described above.

    It looks like you want an Icon A5 on the outside and a bonanza 36/cessna 206/Cherokee 6 on the inside...

    You really don't think the Seawind looks sleek?

    I love amphibians, but what about a more traditional plane and have it on floats 1/2 the year? That might open up more options for you.
     
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  9. Nov 13, 2018 #9

    cgaircrft

    cgaircrft

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    The 13b is capable of 600-700 hp with a turbo, but it requires severe porting and high rpms. I have on an a sand rail. We do not want to run high rpms and in an aircraft want conservative reliable performance. the 20b puts out 300hp naturally aspirated but finding one reasonable priced is impossible. The 13b is about 25% lighter than other engines in the same hp rate, even after adding a reduction unit and liquid cooling. I have the motor all rebuilt, turboed, electronics, reduction unit ready to go. I have used the motor before and am confident with it in a aircraft setup. It has primary and secondary injectors for redundancy, i purchased a electronics system that also implements total redundancy. Its made to run at high rpms all day at abot 10,000 price tag vs. 30,000 for anything with the same performance. Ill try and get a set of plans for this plane. I have a partner to help with the build and we are both craftsmen just need help woth design and engineering. Thanks for your input.
     
  10. Nov 13, 2018 #10

    cgaircrft

    cgaircrft

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    The seawind looks sleek but is way large and heavy in unessacary areas. If theyd selll me plans I'd start there but they wont.
     
  11. Nov 13, 2018 #11

    BJC

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    You have defined a very ambitious project. I wish you success.

    Help with design and engineering is a wide scope of work. While you may get lots of pointers here, some based on solid knowledge, training and experience, you also will get lots of well-intended opinions. You will need to have personal interaction with several people of different skills to get real help. This is not intended to discourage; to the contrary, it is intended to help you understand, and take on, the wide scope of work ahead.


    BJC
     
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  12. Nov 13, 2018 #12

    narfi

    narfi

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    Hey! that's me.... Sorry if I came across wrong.

    This topic does very much interest me as it is very similar to the possible requirements for my 2nd build.

    1. The engine choice. I am very interested in both the NA 13b for a first build 2place and a ported/turboed 13b or 20b for a 4 place amphibian as a second build. I really like the idea of this engine, but want to be careful of overhyped blogs with little details. I would love to see more build threads with these engines and their choices and progress with psrus, cooling, cowlings, plumbing, etc......

    2. 4 place amphibian is something I would really like to build, I would really like to have your thought process spelled out on choices and whys in order for me to fill in missing gaps in my own logic and thought processes when shopping for ideas and plans.
     
  13. Nov 13, 2018 #13

    lr27

    lr27

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    Right.
     
  14. Nov 13, 2018 #14

    BJC

    BJC

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    narfi:

    My comment, that did not say “ignorant”, was not directed at you, me, or any other specific person here. It was a cautionary comment that applies to all internet forums; separating the accurate, useful information from the well-intended, but not accurate, information is an important, and sometimes difficult, thing to do.

    A four place amphib with reasonable cost, ease of building, and performance will be a unique homebuilt. I would love to see the project become reality.


    BJC
     
  15. Nov 13, 2018 #15

    narfi

    narfi

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    You are right, and I took no offense, but i can keep digging myself deeper as is often the case on the internet....
    I just meant to agree with you, and say that I do not have any actual experience with 4 place homebuilt amphibians, so it is true that I am (inserted myself) ignorant to some extent.


    I have worked on certified aircraft for 20years, Cessnas on straight floats in the fleet I maintain, lots of stuff on beavers and other odds and ends, mauls, cubs, etc... the only amphibian I have ever touched was a Lake and all I did with it was change a mag and I have never done any maintenance on any experime.
    I do know some things in life, but for this one area which seems to be my obsession I have zero real life experience other than years of reading and researching. It is only fair that if I make a comment or give advice it is known where I am coming from.


    I agree with this, and really hope that cgaircraft will continue to post his thought process and then build process towards this goal.
     
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  16. Nov 13, 2018 #16

    spaschke

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    I know a guy that has a flying Adventurer 333 he is willing to sell pretty cheap. The interior is basic (unfinished really). I think he has 25 hours on it. It gets off the ground/water faster than most other amphibs. It has similar flying characteristics as a Lake. 4 seat. Can sleep 2 in the back if you take the rear seat out. Relocated the radiator for better cooling and W&B.

    Steve
     
  17. Nov 13, 2018 #17

    lr27

    lr27

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    Now there's a design you'd want to do a bit of homework on before making a decision.
     
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  18. Nov 13, 2018 #18

    narfi

    narfi

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    1333 useful and if using the 13b probably over 1400 is a 'true 4 place'...... nice check mark there
    It is very square and boxy looking, not my personal taste in 'sleek' but that is very subjective.
    Sleeps 2? even better! That is some serious cabin space.

    Not sure how cheap your friends flying one is, but here is a 2yr old add for an unfinished kit w/ engine pretty cheap,
    http://sky4buy.com/Adventure-Air-333-Amphibian-112008140241/07869
    I will have to do some more research myself :)

    What do you know that can be put down in the minus column other than subjective looks?
    (high centerline thrust is going to be an issue with any of these sort of planes and from what I have read can be mostly alleviated with proper training, so cant be held against one if that is the category being looked into)
     
  19. Nov 13, 2018 #19

    BBerson

    BBerson

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  20. Nov 14, 2018 #20

    cgaircrft

    cgaircrft

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    No offense taken, I appreciate all input and am not thin skined. Several threads are available on the Mazda engine in aviation. The authority on the subject retired, and his rotary engine company has dropped the aircraft divison. His name is Tracy Crook, hes written a book on his conversions. Also Charles has built a cozy with the turbo rotary and has a great thread with alot of info. My experiences so far with the rotary motor has been in sand rails. I have researched, read boks and blogs on the conversion to Aviation applications. I know this project will be a major challenge for me. I have several on my team, my good friend has built several aircrafts and is right now in the process of building his own 4 seat amphibious airplane which he has converted a tricycle set of plans to his own version of amphbious, I would like a little closer beginning position, or his in the air first. There are a ton of 2 seaters, then they jump to very large not very efficient planes. the sea wind actually recomends 350-400 hp. I dont like they way they put the motor on the tail in a puller configuration. I want my motor above the cabin in a pusher configuration. Locating the motor on the tail required extra support and a very extensive rear fuselage and tail section.
     

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