Turbofan

Discussion in 'Boat Design' started by dskira, Feb 18, 2013.

  1. FranklinRatliff

    FranklinRatliff Previous Member

    Airscrew Propulsion

    This is the 70 mph Bell-Baldwin HD-4 hydrofoil boat. Airscrew propulsion in fast marine craft dates back almost 100 years.
     

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  2. FranklinRatliff

    FranklinRatliff Previous Member

    Lippisch Ramwings

    Ramwing craft designed by Dr. Alexander Lippisch (father of the delta wing, designer of the first 600 mph airplane and the fastest fighter of WWII).
     

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  3. FranklinRatliff

    FranklinRatliff Previous Member

    Airscrew propulsion was used by the Luftwaffe during WWII to convert unpowered barges into self-propelled craft. Fuel economy was obviously not a concern since these craft were not intended to travel long distances.

    "Type AF [Barge]
    The Luftwaffe had formed its own special command (Sonderkommando) under Major Fritz Siebel to investigate the production of landing craft for Sea Lion. Major Siebel proposed giving the unpowered Type A barges their own motive power by installing a pair of 600 hp surplus BMW aircraft engines on them. The Navy was highly skeptical of this venture but the Army high command enthusiastically embraced the concept and Siebel proceeded with the conversions.

    The aircraft engines were mounted on a platform supported by iron scaffolding at the aft end of the vessel. Cooling water was stored in tanks mounted above-deck. As completed, the Type AF had a speed of 6 knots and a range of 60 nautical miles (unless auxiliary fuel tanks were added). Disadvantages of this set-up included an inability to back the vessel astern, limited maneuverability and the deafening noise of the engines which would have made voice commands problematic.

    By 1 October, 128 Type A barges had been converted to airscrew propulsion and, by the end of the month, this figure had risen to over 200.

    The Kriegsmarine later used some of the motorized Sea Lion barges for landings on the Russian-held Baltic islands in 1941 and, though most of them were eventually returned to the inland rivers they originally plied, a reserve was kept for military transport duties and for filling out amphibious flotillas."
     
  4. FranklinRatliff

    FranklinRatliff Previous Member

    Airboats

    Big twin-engine airboat used to haul away debris after a Louisiana hurricane.
     

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  5. daiquiri
    Joined: May 2004
    Posts: 5,371
    Likes: 258, Points: 93, Legacy Rep: 3380
    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    At the end, you should have immediately state that you intend talking about high-speed vessels and not about "the speed regime in which marine craft normally operate". A lots of bitter comments could have been avoided.

    Anyways, those are some nice examples of daring engineering.
     
  6. FranklinRatliff

    FranklinRatliff Previous Member

    Airboats

    Examples of the technology behind airboats.
     

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  7. yipster
    Joined: Oct 2002
    Posts: 3,486
    Likes: 97, Points: 58, Legacy Rep: 1148
    Location: netherlands

    yipster designer

    ok first OB is a turboprop but how bout a water pulse jet ?
    simplicity, direct cooled drive and these water pulse jets are proven to work
    though not superior to regular OB's but only wonder how poor or if these jets could suit a swath..

    do i remember they kill fish and might be better suited on a fishing boat :confused:
     

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  8. FranklinRatliff

    FranklinRatliff Previous Member

    Pulsejets

    I don't know, other than they're lightweight, can probably be scaled up, and would allow for some creative packaging of the propulsion system.
     
  9. FranklinRatliff

    FranklinRatliff Previous Member

  10. FranklinRatliff

    FranklinRatliff Previous Member

    Turbofans

    Two turbofan engines designed to operate well near ground level are those used in the A-10 attack aircraft and Harrier VTOL fighter.
     
  11. Submarine Tom

    Submarine Tom Previous Member

    FR,

    Well said.

    Again, astonishing level of knowledge displayed here in your posts, nicely done.

    I misspoke earlier, I was wandering if you had penned any books I might look up.

    Also, I missed where you acquired your outstanding education.

    What institution did you attend?

    Your posts are fascinating but I'm struggling to grasp your point.

    What is it, may I ask, you are getting at.

    If you wouldn't mind expanding on that I'd be tickled pink.

    Thank you for your valued contribution and stimulating text.

    Admiringly,
     
  12. FranklinRatliff

    FranklinRatliff Previous Member

  13. FranklinRatliff

    FranklinRatliff Previous Member

    My point is simply NO POINT beyond providing background information that people can use to either correct misconceptions if they have them or as building blocks to expand their concepts.
     
  14. Submarine Tom

    Submarine Tom Previous Member

    Ohhhhhh... I see, so your point is no point, or pointless I guess I could say.

    Lol, pointless, sounds a bit funny doesn't it.

    Who knew this would turn comical.

    Well, if it's pointless then even I get it!

    Thanks.

    Any books you've published I could read up on?

    Did you not go to University then?

    Come on, spill the beans.
     

  15. FranklinRatliff

    FranklinRatliff Previous Member

    Ever hear the parable about "spreading pearls before Submarine Toms..."?
     
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