High Performance MPX Foil/Self-righting Trimaran-The Test Model

Discussion in 'Multihulls' started by Doug Lord, Dec 28, 2010.

  1. hoytedow
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    hoytedow Carbon Based Life Form

    That was really cool.
     
  2. daiquiri
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    daiquiri Engineering and Design

    Doug, compliments for having it completed. It is a big and complex model. :)

    I was watching the video, but it is too blurry to evaluate the behavior of the boat in that wind condition. Only the last minute or so of the video has a sufficient quality to allow some qualitative observations.

    What puzzles me is the boat's behavior from 4:15 to 4:20. It looks like you were close reaching or beam reaching there. At 4:17 it pitched up and then broached while flying for a moment with the T-foil out of the water. My first impression was that the T-foil is placed too forward with respect to the sail, or that it gives too much lift. Or perhaps it is just that you need time to acquire the right feeling for the boat's movements.
    What was your impression about this, in that moment?
     
  3. warwick
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    warwick Senior Member

    I think it will be interesting to see once you get use to sailing and tuning it Doug, Keep up the work.
     
  4. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development--First Flight!!!!!!!!!!!

    =======================
    Thanks, Slavi. I'll look at it again when youtube finishes getting rid of the shakiness. The sail control system let go at one point so the jib was luffing and I couldn't adjust the main. I have reserved this day for celebration-work will resume tomorrow.
    We are going to fix the video-its too damn bad about the go pro because we need it now. Dan and I are going to build a tripod out of carbon tubes so the camera can be brought out to deeper water. Dan was afraid he'd drop the thing but it has to be fixed-and it will be.
    In sailing the boat it was amazing-it was vastly overpowered yet was controllable and even recovered from a pitch pole(skipper induced). Several times(only once on video I think) I sailed the boat at her designed angle of heel with the lee hull slightly out of the water. I was struck by her pitch and roll stability-much more so than any model tri I have ever sailed. I could "feel" when the main foil downforce kicked in-it was awesome-a word I don't use often. I couldn't be more satisfied-we now know she will fly and fly well. And I 'll try to work out a way to get Scott to make me a shorter main so we can switch out in conditions like today.
    The scientist in me wanted to pack it back up when the conditions increased so much, but the sailor in me said to hell with that. Those were absurd conditions for the first foiling sail-the waves were too big, the wind too strong-there was simply no way to make meaningfull adjustments. But the sailor in me had a blast-I liked the pitchpole because of how well the thing recovered. A 21lb boat flew the main hull and flew stably in dynamically unstable conditions. And she foiled the whole boat for short distances. The scientist in me says thats what you get for sailing in those conditions before everything was properly adjusted. The sailor says ,yeah, wasn't it so damn cool.........
    PS note there are a few instances of a dynamic pitch up-one I remembered from sailing(not sure its on the video) where I adjusted the sheet too far out and wham she pitched up-that's a characteristic of a foiler not sailed well. It can also happen if the boat is over-steered.
     
    Last edited: Jul 1, 2014
  5. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development----First Flight!

    ==============
    Thanks, Warwick! I couldn't be more pleased-we know it flies-just needs a bit of tuning to make it perfect. Sailing the Fire Arrow today was just a blast-the fact that there was something wrong with the sail control just added to the rush in some peculiar way......
     
  6. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development--First Flight!!!!!!!!!!!

    ====================
    That was the result of two things: sudden loss of the jib and an over-steer on my part. That was completely skipper and component induced and really has nothing to do with improper foil placement. The proper foil placement is shown by the examples of steady flying of the main hull. She was a handfull with the sailwinch problem and with my inexperience with the boat. But only a great boat could do what she did today! (Sorry, I couldn't help myself)
     
  7. Doug Lord
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    Doug Lord Flight Ready

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    Thanks, I appreciate that. It's just going to get better! It sure was fun sailing her....
     
  8. Doug Lord
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    Doug Lord Flight Ready

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    Thanks, Hoyt!
     
  9. DennisRB
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    DennisRB Senior Member

    Impressive for a shakedown run in unsuitable conditions. I think this will work out as planned. Congrats. :)
     
  10. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development--First Flight!!!!!!!!!!!

    Thanks, Dennis-still don't know what let go-that's for tomorrow. Whats different about today than yesterday is that today we know the foil system works. It's just a matter of sailing in flat water and less wind to get them dialed in-they're awfully close now. I'm mighty satisfied,I'll tell you that. And I think the Wing Tip looks good and may work....(almost needed it!).
     
  11. DennisRB
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    DennisRB Senior Member

    Am I allowed to say that was the most exciting part of the vid? :D
     
  12. Darth Reapius
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    Darth Reapius Junior Member

    Looks close... Appears airborne a few times through the video, looks like you need to sheet on a tiny bit and head off... seems to lack drive and sink that amas, i recon speeds your friend hey, that rudder should stop pitching if its at speed, although jesus that rig looks huge and OP for those conditions even... could just try it in those conditions without the main foil maybe...
     
  13. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development----First Flight!

    ====================
    The video is fixed so I'll spend time watching and re-watching today. When I sailed yesterday I saw light under the lee hull a couple of times. There is no doubt in my mind that the foils will need AOI adjustment. Keep in mind that something let go in the sheeting system-looks like a line may have jumped the drum-but I'm still not sure. That made control difficult in the conditions-I only hope I didn't over stress the winch cause that's big dollars.....
    But the main foil worked in lift and with downforce yesterday and the ama foils were lifting close to their maximum.
    The main foil is at +3 degrees and should probably come down to +2.5 where the F3 foils were set. The ama foils are set at 3.75 degrees-don't know about them yet. The thing is very sensitive to rudder control. The dynamic pitch-ups look to be skipper related. The mainfoil worked very well-I think that makes the boat. The wind was marginal for flying the main hull w/o the main foil. We'll get it right. Next time we'll wait until the conditions are just right for foil set-up and testing.
    PS- the pitchpole was operator error as well but she did a Team New Zealand and popped back up! Glad I got that Wing Tip in place, though....
     
  14. Doug Lord
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    Doug Lord Flight Ready

    MPX Testing and Development----First Flight!

    ================
    You bet-I enjoyed that too. But I wouldn't call it the most exciting part of the video from a designer/builder perspective.
     

  15. cavalier mk2
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    cavalier mk2 Senior Member

    Keep it up Doug! A good foiling phrase there:)
    I've been too busy to keep track of much but it is great to see you made it too the water. Perseverance pays! Remember to adjust one thing at a time in the interests of science.
     
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