Kind of a boat... well, almost.

Discussion in 'Boat Design' started by Externet, Jan 20, 2014.

  1. Externet
    Joined: May 2009
    Posts: 35
    Likes: 1, Points: 0, Legacy Rep: 24
    Location: Mideast U.S.

    Externet Junior Member

    At least is meant to float.

    What would you use to make aircraft type floats that can survive traveling at ~50 mph on 2 ft waves sea, NOT meant to take-off airborne, ever ?

    The aim is to attach them to a 6 seater 'discarded' non-airworthy aircraft, without wheels, no instruments, will only travel by 'skiing' fast on the surface. In other words, a pontoon airplane that will never lose contact with water, registered as a boat.

    The 'standard' aircraft pontoons are way too expensive to consider even used. 20" PVC ? Aluminium tubes like pontoon boats ? ...?

    Please, out of the box thinking for this lunatic contraption. :rolleyes:
  2. Stumble
    Joined: Oct 2008
    Posts: 1,913
    Likes: 73, Points: 48, Legacy Rep: 739
    Location: New Orleans

    Stumble Senior Member

    Foam with a carbon skin would be my preference, possibly with an aluminum skid plate on the bottom. Fiberglass over foam for second preference.

    Aluminum tubes stiff enough to handle a water landing would have to be very thick walled, which would add a lot of weight to the plane.

    I have no idea what type of scantlings would be required though.
  3. gonzo
    Joined: Aug 2002
    Posts: 16,645
    Likes: 1,609, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Even a non-airworthy airplane will cost a fair amount of money. If pontoons are out of your price range, the plane most likely will be too. I think it could be much cheaper, efficient and seaworthy to get a boat and add foils.
  4. messabout
    Joined: Jan 2006
    Posts: 3,345
    Likes: 481, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    If you can score an aircraft engine and prop, then just build an airboat and be done with it.

    The airboat is nothing more than a short wide, flat bottomed, barge like structure. It will go 50 MPH more or less without much coaxing. It can also skim over extremely thin water, even wet grass. They are noisy and unwelcome in places where there are people who are offended by the din. That would be most places and most people.

    Airboats and aeroplanes are also a bit expensive to operate because of fuel consumption. Airboats are pushers where the pilot sits in front of the engine and prop. It uses an air rudder mounted behind the prop.

    On an airboat or the aircraft that you envision, you will need to enclose the prop with a cage of some sort. I suggest that you do some research about licensing in your state. Your idea may or may not be legal.
    1 person likes this.
  5. Petros
    Joined: Oct 2007
    Posts: 2,936
    Likes: 148, Points: 63, Legacy Rep: 1593
    Location: Arlington, WA-USA

    Petros Senior Member

    find a trashed catamaran or beach cat, without rigging, and use the hulls. they should be sturdy enough, and cheap. Search Craig's list, or boat yards for abandon catamarans.

    do not use any aircraft parts on it or it will be too costly. Even a junk aircraft engine has a lot of value, so you will want to find some other type of engine, a honda civic engine perhaps? Or an air cooled motor cycle engine would be a good bet. You can make your own prop out of laminated wood, you can get plans on the internet.

    good luck.
  6. LP
    Joined: Jul 2005
    Posts: 1,418
    Likes: 58, Points: 58, Legacy Rep: 584
    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

  7. messabout
    Joined: Jan 2006
    Posts: 3,345
    Likes: 481, Points: 83, Legacy Rep: 1279
    Location: Lakeland Fl USA

    messabout Senior Member

    Many of the airboats in Florida use Continental or Lycoming engines. More than a few of them use 5.7 liter V8s.
  8. hoytedow
    Joined: Sep 2009
    Posts: 5,857
    Likes: 400, Points: 93, Legacy Rep: 2489
    Location: Control Group

    hoytedow Carbon Based Life Form

    I forgot to ask about the engine but it looks like it came from a truck:

    Attached Files:

  9. Externet
    Joined: May 2009
    Posts: 35
    Likes: 1, Points: 0, Legacy Rep: 24
    Location: Mideast U.S.

    Externet Junior Member

    Thanks, gentlemen.

    The aircraft is a high wing, the missing engine transplant to be for sure 300+ horsepower automotive type; and for floats as suggested, somewhere between a sizable junk catamaran and aluminium pontoons look so far as convenient candidates.
    The purpose is daily commute in enclosed cockpit.
  10. nimblemotors
    Joined: Jun 2009
    Posts: 244
    Likes: 3, Points: 0, Legacy Rep: 4
    Location: Sacramento

    nimblemotors Senior Member

    Sounds like you are trying to skirt the laws regarding an airplane by registering it has a boat and keeping it in the water. I like the thinking.
    Skimming on pontoons is going to consume a lot of fuel,
    I would make it a hydrofoil to keep the minimum parts in the water.

    The flat bottom of an airboat would be hell in waves, they excel in flat water.
  11. Skyak
    Joined: Jul 2012
    Posts: 1,459
    Likes: 142, Points: 63, Legacy Rep: 152
    Location: United States

    Skyak Senior Member

    At the speed and wave state you specify the shock forces from wave strikes will be brutal and the cost and weight of hulls that can take the punishment will be high. A better concept is to get off the water a foot or so at maybe 20mph and fly in the 'ground effect'. It would be a far better match for your air frame and prop.

  12. Westfield 11
    Joined: Apr 2008
    Posts: 215
    Likes: 8, Points: 0, Legacy Rep: 95
    Location: Los Angeles

    Westfield 11 Senior Member

    Hitting any sort of waves for very long will destroy the float and structure. They are designed to only support the full weight of the plane at slow speeds, higher speeds will see most weight taken up by the wings. This means that any wave struck at speed before takeoff is only impacted by a fraction of the weight. Less weight, less stress. You will not have this effect in your behalf and will be in a worst case scenario: high weight, high speeds, high stress and impact loads and all of this over a long and continuous duration as opposed to a short takeoff or landing run.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.