Why no aerodynamic control/stabilizer surfaces on high speed cats?

Discussion in 'Boat Design' started by RatliffFranklin, Jan 24, 2007.

  1. skullhooker
    Joined: Sep 2007
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    skullhooker Junior Member

    FranklinRatliff, what on earth has crawled up your backside? I can't beleive you have the nerve to anonymously post that kind of language and garbage here! Is this some kind of "Jerky Boys" comedy skit?
     
  2. FranklinRatliff

    FranklinRatliff Previous Member

    Geniuses

    Newsflash, Sherlock.

    The first thing people saw was "FranklinRatliff Senior Member" in at least 14 point font.

    Get back to me when you have even the least comprehension INCLUDING YOUR OWN *****' NAME doesn't mean "anonymously."
     
  3. skullhooker
    Joined: Sep 2007
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    skullhooker Junior Member

    No, I mean when you talk **** and insult people over the computer. Do you walk around and talk like this to people face to face on the street? I don't think you would last very long. You'd meet your match real quick. I've been around long enough to know that's true.

    I couldn't believe I was reading your spew. At first I thought it was a joke.

    I read your other posts and you have interest in high speed craft - you actually have some good points to add to the discussion. Then in others you start your trash mouth rantings. What's up with that? As long as the discussion goes your way you're cool with that? And then when you get challenged or someone writes something other than you're looking for, here comes the dumshit, ******* ********* , whatever?

    People with class don't act that way, or didn't your mother tell you so?

    "Senior Member" ? You're a complete disgrace. You should have the title "gutter mouthed trailer trash".

    Back to the zoo with you.
     
    1 person likes this.
  4. RatliffFranklin

    RatliffFranklin Previous Member

    Lessons to learn

    In the real world I can be more selective with my associates and normally don't have to put up with ******** from instant experts who've never given a thought to a particular idea or concept in their lives but when it is raised they all of a sudden know everything there is to know about it. You need to learn there are those who use civility as a front to hide their spinelessness and ********.
     
  5. kach22i
    Joined: Feb 2005
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    kach22i Architect

    Pericles, this thread was dead for a year, and in my opinion would of been better off left that way.

    I did go to Florida last year, but was too busy to visit RatliffFranklin, would of been interesting though.

    Since the splashy appearance of RatliffFranklin, he somehow soon afterwards became able to managed to himself.

    He has posted quite a few good things since then, and I no longer have a quarrel with him. He is still opinionated but not the same man he used to be in the Hot Rod forum.

    Sleeping dogs and all that.:cool:
     
  6. RatliffFranklin

    RatliffFranklin Previous Member

    Thinkers

    There's a much higher quotient of actual analytical thinking on Boat Design than there is on Hot Rod. Trust me on that one.
     
  7. skullhooker
    Joined: Sep 2007
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    Location: Indialantic, FL

    skullhooker Junior Member

    Ratliff, like kach22i said, you have had good things to add to the discussion. Still, no matter how spineless, clueless, anal retentive, and stubborn someone may appear, you don't have to blow your cool and foul the air. If you just want the aerodynamics and dynamic response of a jet/rocket powered craft and don't want the input of a retro wood boat builder, just say so and be polite.

    You may just find that those same folks you somehow think you despise may enlighten you to all kinds of wonderful insights and bestow knowledge that would take you years to find out on your own.

    That's really why we're all here. For the love and obsession of the water and boats.

    I'm done.
     
  8. RatliffFranklin

    RatliffFranklin Previous Member

    Wooden boats

    The last two boats to set the WSR were both wood.
     
  9. skullhooker
    Joined: Sep 2007
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    skullhooker Junior Member

    There you go!
     
  10. NADreamcatcher
    Joined: Oct 2007
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    Location: Michigan

    NADreamcatcher Junior Member

    wings on boats

    Franklin, Thanks for the info on the SeaDart. Im not an aerodynamacist but seems to me that vertical stabilizers on a boat are not always desired...ie, cross winds and peculiar down drafts and their effect on the direction the craft is trying to go hydrodynamically etc.? Horizontal and roll stability sure...but if the craft is not completely in flight and these aero control surfaces you propose should be there only have a small window of effectiveness. You know stall speed...angle of attack and so on... Anyway... whats your point of the post? Are you trying to convince yourself of something or teach us? Hopefully we can learn from each other?

    NAD
     
  11. RatliffFranklin

    RatliffFranklin Previous Member

    Aerodynamic Surfaces

    The big offshore tunnel hulls are now running in the same speed envelope as Unlimited hydroplanes, except Unlimiteds have driver-operated canard wings, vertical stabilizers, and adjustable rear wings.

    Among other benefits, a substantial vertical stabilizer would give a big tunnel hull skidding sideways more roll stability.
     
  12. NADreamcatcher
    Joined: Oct 2007
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    NADreamcatcher Junior Member

    I have seen unlimiteds skidding sideways, but cant say i have seen a cat do it. You said you are a pilot, so what happens to a plane in a cross wind? Does it go straight without rudder? If you add vertical on a cat that has good hydrodynamic linear stability, turn in a crosswind it will help it roll over not stop it. Unfortunately air is invisible and water and air just dont mix well do they?

    Large cats are already more stable than any unlimiteds while airborne. Horizontal control would be much more beneficial than vertical! But you like to argue about everything dont you? imo

    NAD
     
  13. RatliffFranklin

    RatliffFranklin Previous Member

    Aerodynamic Surfaces

    Because the center of force on a large dorsal fin acts above the center of gravity, it provides a counterroll in a sideslip condition. Simple fact. Lockheed Skunkworks understood it fifty years ago.

    If you think big offshore tunnel hulls never skid sideways, then you haven't seen aerial shots of them going through turns at races such as Miami.
     
  14. charmc
    Joined: Jan 2007
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    charmc Senior Member

    NAD,

    While I don't entirely agree with RF's predictions on the effect of a dorsal fin on offshore cat performance, the question that began the thread is a valid one, IMHO. The fact that there are not any yet doen't preclude the possibility of one being added as speeds continue to climb.

    Offshore tunnel hull cats don't skid as much as hyroplanes, obviously, but they do skid a bit in turns. The dynamics are different in an offshore racer, because it's possible to reduce speed just enough to submerge a bit more of the narrow hulls to get more grip through the turn. As offshore peak speeds approach 200 mph, though, aerodynamic forces will play a bigger role.

    Your comment about air being invisible and not mixing well with water actually summarizes the challenge of high speed powerboat racing. The fastest boats operate at the interface, with nearly all the hull out of the water for minimum resistance, yet relying on the higher density of the water for support and propellor propulsion. Because they are so very different in density (water is 784 x air density at sea level), managing both air and water dynamics is a huge task. With 95% of the hull out of the water and in the airstream, aerodynamic controls might make sense. Think about videos of severe hurricanes and tornadoes, which are just invisible air moving at relative speeds of 140 mph and higher.

    An aerodynamic control surface could, as you say, contribute to a rollover, but that's a matter of proper design. I don't profess to know any of the answers, but I think RF is correct in his belief that aerodynamics will play a bigger role in offshore racer design as speeds continue to increase.
     

  15. NADreamcatcher
    Joined: Oct 2007
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    NADreamcatcher Junior Member

    Charlie,
    Very well said! Your response is appreciated!

    While on the subject, how would you equate water or air density and it's effective density as it relates to speed?

    NAD
     
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