High speed blue water hydrofoil

Discussion in 'Projects & Proposals' started by MurphyLaw, Jul 25, 2018.

  1. MurphyLaw
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    MurphyLaw Senior Member

    Just located some load cells at my local electronics supplier that can do up to 1000kg at 0.02% error, which should be more than enough for any one foil. Only $40 I will get one then use it for lift and if it works well then get another to measure drag. If I use these I could make the foils run in closed loop control always producing the least amount of drag for the lift required no matter the conditions. Google "Load Cell 1000kg" for list of suppliers in your own area.
     

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  2. MurphyLaw
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    MurphyLaw Senior Member

    Looking at how to put this thing together, I'm convinced it can be done with 2 foils instead of 4. Anyone doubting needs to go ride a Segway, you can throw yourself forward as if you will surely face plant and the thing reacts so fast that it catches you, most modern aircraft would fall out of the sky if there wasn't a computer flying them, in fact that Air France flight went down in the Atlantic near Brazil because the co-pilot took over and made a mess of things, I am going to make a model like this and see what's the story.
     

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  3. Doug Lord
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    Doug Lord Flight Ready

    Foilers come off their foils for many reasons even if they can fly thru a tack or gybe(which only the very,very best can do)-you need a great hull design and a long round tube is probably not it.
    Two foils might work if one was the main foil and the other was the trailing rudder foil(aircraft configuration-other configurations might work) but two main foils side by side would not be likely to be stable in pitch. A typical mainfoil set-up is +2.5 degree's AOI relative to the design static waterline(parallel to the flight waterline after takeoff) and zero degrees for the rudder foil(s) with the mainfoil taking around 80% of the load. The 20% of the load the rudder(s) take should be 20-50% less in pounds per sq.ft. than the mainfoil(s) loading in pounds per sq.ft..
    The foil span you show in your renders is waaay too small.
    Don't hesitate to spend some time looking at successful foilers and their foils. You might consider building a sailing/flying model of an existing foiler just to get the hang of what works and why. Or rent a good foiler (with a little help) and analyze it carefully....
    Good Luck!!
     
  4. JamesG123
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    JamesG123 Senior Member

    It "catches you" because the wheels roll forward to restore your center of gravity. High performance statically unstable aircraft still have control surfaces with which to maintain controlled flight. Where do you get the leverage to do the same with your foils?
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    One fears there is a Walter Mitty-esque quality to this project, but I will be happy to proven wrong.
     
  6. MurphyLaw
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    MurphyLaw Senior Member

    A round tube is best for performance but worst for crew comfort, I'm not interested in crew comfort, but from my experience keeping dry while you rest is the most important factor for crew endurance. look at the Sea SLICE craft that Lockheed Martin produced, then you shouldn't forget that there are many STOL aircraft that are lifting 3000kg at only 40kts no problem and that is out of ground effect, in ground effect where any foiler lives the speed is lower.
     

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    Last edited: Aug 2, 2018
  7. MurphyLaw
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    MurphyLaw Senior Member

    You get the leverage from the wing above the sails, if you pitch forward then you increase the lift of the wing. at 40kts you should be flying in ground effect and only using the contact with the water to provide your forward speed.
     
  8. MurphyLaw
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    MurphyLaw Senior Member

    "Only those who attempt the absurd can achieve the impossible"
     
  9. JamesG123
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    JamesG123 Senior Member

    Uh... thats really not the way it works. If you pitch forward, you decrease the Angle of Attack of the wing, decreasing its lift. Beyond that... So you are saying it's CoG is going to be forward and you are going to rely upon aerodynamic lift to maintain trim and stability? What happens when there isn't enough wind to provide that counter force but enough to get on the foils? Pitch-poleing isn't fun.

    Not going to get much rest while your craft is beating you to death, no matter how dry you are.

    You should really build a real model of this that goes in real water and real air and see if your ideas are actually practical.
     
  10. MurphyLaw
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    MurphyLaw Senior Member

    I am going to build a model and experiment in my swimming pool, the windy season that lasts until December should be here soon, it arrives in August sometime so the timing is perfect, it blows at 20kts+ all day. Yeah I think you need a small wing at the front of the craft, but if you look at the sail rocket the front float is not a foil it is just a rudder, so the craft is balancing in the centre. And they could not get it to work until they added the winglet at the base of the sail.
     
  11. MurphyLaw
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    MurphyLaw Senior Member

    OK I figured out a way to make the foil control system independent of the hull/floats. Save myself a fortune in construction if the hulls don't need to be able to transmit the loads from the wing to the foils also I can develop the control system and bolt it to existing hulls. I am going to make the parts out of carbon fibre and then press fit metal faces for bearings to run on. You mold the carbon fibre with indents and then cut metal inserts then stick them in the oven or into dry ice, depending on whether they are outer or inner, then when they reach room temp they are never coming off.
     

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  12. MurphyLaw
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    MurphyLaw Senior Member

  13. Mr Efficiency
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    Mr Efficiency Senior Member

    Even mundane boats are difficult to realise on a shoestring budget, this project is far from simple, and looks like a money muncher to me.
     
  14. MurphyLaw
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    MurphyLaw Senior Member

    Less than the price of a new car, no problem, stay clear of the circus paraphernalia. A single servo motor replaces dozens of pulleys , ropes and cleats etc and the parts count has always been inversely proportional to reliability no matter the technology employed and half the gear on a new boat is there because the owner can't sail or navigate not because it is a necessity. If weight wasn't an issue I could knock this up with what I have in my yard and it would only cost my time. If you look at the type of boats that have been used for similar fast ocean crossings, real crossings by real sailors on their own budget and not a flotilla of multimillion dollar support boats and helicopters, they go for a Tornado type catamaran with a few meters added to the bow and the bridge deck clearance raised about 1.5m, then they string up netting from the mast so they can get out of the spray while they sleep. I was going to convert my Tornado in similar fashion but figured something from scratch purpose built would be better.
     

  15. MurphyLaw
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    MurphyLaw Senior Member

    Here is a STOL with a stall speed of 35kts, now the area of a 40ft boat's deck and sides must be more than the area of this wing, if you going to have that much area of a boat with the wind passing over it, you may as well try and incorporate that area to produce lift in some way, you are also not sailing directly into the wind so that area is producing crazy amounts of drag which is where the sail rocket is radically different from other foiling craft, the hull points into the wind. Future foil craft, will accelerate upto 40kts on foils then the foils will retract and you will have an aircraft with a single keel in the water maintaining stability and lift using the air and using the keel to convert some of the wind energy to forward motion. The Sail Rocket when it is at top speed only has a single foil in the water and a rudder the other appendages are there to act as balance stops...and the key to getting stability was adding a winglet to counter pitching and not adding another foil to the rudder. I only have to lift half of what this aircraft lifts, so If I took one of his wings and put it above 2 masts like in my last render then it would produce enough lift to not need the foils and removing all the foil surface would be a big reduction in drag enough to get your another 20kts at least.

     
    Last edited: Aug 3, 2018
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