Twin mono

Discussion in 'Mono Forum' started by David Ashcroft, Feb 2, 2019.

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  1. Feb 2, 2019 #1

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    I have a build starting but wanting peoples opinions 

    Am looking to keep weight at 14-15lb less fuel.

    Using Nova 91 engines..

    Bare hull is 7.5lb

    Length 50" 

    Width 14".

    20190202_144247.jpg

    20190202_144527.jpg
     
  2. Feb 2, 2019 #2

    gilbert galli

    gilbert galli

    gilbert galli

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    Last edited by a moderator: Feb 2, 2019
  3. Feb 2, 2019 #3

    brad nichols

    brad nichols

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    Gilbert has that twin ran yet?? It would be great to see some video. Looks a little crowded in there.

    Brad
     
  4. Feb 2, 2019 #4

    gilbert galli

    gilbert galli

    gilbert galli

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    Code:
    video of the first tests with octura propellers x465, the x465, x467, x665 ares too small with 25% nitro
     
  5. Feb 3, 2019 #5

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Gilbert that is a excellent build very well done..

    I also was going to build as subsurface to help lift the hull out of the water .

    I remember John Finch stating along the lines of ,with a subsurface setup the hull can have a tendancy to float and chine side to side , A bit similar to how your friends hull was performing.

    Do you know how much the finished hull weighed?

    Great thanks for showing.
     
  6. Feb 3, 2019 #6

    ALLAN YUEN

    ALLAN YUEN

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    I remembered that Jerry Crowther has twin mono with CMB 80s . He told me that his boat was weight around  19lbs and faster &stable 
     
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  7. Feb 3, 2019 #7

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Thanks Allan .

    19lb is a porker ,, but yes I believe  extra weight is necessary for stability and not affect good top end speed..

    Also i think a CG of around 38% would benefit without using Tabs and then I would just use the struts to trim ride...
     
  8. Feb 4, 2019 #8

    ACTION JACKSON

    ACTION JACKSON

    ACTION JACKSON

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    What are the white cylinders in front of the motors. Nice looking boat. Should be scary to drive. 
     
  9. Feb 4, 2019 #9

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Hopper tanks Action...
     
  10. Feb 4, 2019 #10

    gilbert galli

    gilbert galli

    gilbert galli

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    Code:
    these are tanks with constant level, equipped with solex carburetor needle and the float is a ball of deodorant,
     David the weight without fuel is 8.2kg
     
    Last edited by a moderator: Feb 4, 2019
  11. Feb 5, 2019 #11

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Thanks Gilbert ,,

    I did not see in your build thread ..but are you using a Y harness for the 2 throttle servos?

    That was my plan to use a Y Harness,,,save space and extra weight,of a mechanical system .And will use manual needles also.

    Edit. At a closer look Yes. I did now see your servo setup .

    Thanks
     
    Last edited by a moderator: Feb 5, 2019
  12. Feb 5, 2019 #12

    Dennis Somers

    Dennis Somers

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    David, looks like a fun project.

    Gilbert, your friend's boat is very nice. The hopping in the turns and the straights is from the transom lift of those Octura props. You don't want lift in a mono prop. There are many more blade options in the newer ABC line-up that will settle the hull much better and produce faster, smoother lap times.

    Have fun!
     
  13. Feb 5, 2019 #13

    gilbert galli

    gilbert galli

    gilbert galli

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    Dennis,


    the next tests will be done with octura 16/67 and propshop 67 17/3 cleaver,  with  the octura series X the boat was too aerial, we put a little négative to the struts and lowered a little the flaps
     
  14. Feb 5, 2019 #14

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    The X series props are non lifting.
     
  15. Feb 5, 2019 #15

    Dennis Somers

    Dennis Somers

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    "The X series props are non lifting."

    That has been the story line for years. Believe what you will.

    Back in the day, we tested with X4s, X5s, and X6s. Every one of them needed cupping and back cutting to make them usable for monos.
     
    Last edited by a moderator: Feb 6, 2019
  16. Feb 5, 2019 #16

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Den

     1 -Gilberts boat is a subsurface setup so naturally the hull will have more lift as oposed to surface drive.

    2 - The CG maybe a little off perhaps

    3 - The struts may need adjustment

    Considering he only just first testing it was very good.

    I know you like to debate Dennis so perhaps go back to Jims and play there haha...
     
  17. Feb 5, 2019 #17

    Dennis Somers

    Dennis Somers

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    No debate Dave. Just stating my experience with X props in years past.

    If people don't share their opinion and experience, there is no forum. If you don't want me on your threads, no worries.

    Enjoy your project.
     
  18. Feb 5, 2019 #18

    aaron alberico

    aaron alberico

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    X series props are NON LIFTING PROPS....

    Dave can’t wait to see it finished..   :)  
     
  19. Feb 6, 2019 #19

    David Ashcroft

    David Ashcroft

    David Ashcroft

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    Thanks Aaron just waiting on engines to be massaged.

    Allgood Dennis just havin a bit of a joke..

    At least you have shown some interest..unlike others haha.
     
  20. Feb 6, 2019 #20

    johnsteltzer

    johnsteltzer

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     X4 are low lift general purpose props

    M4 is similar to X4 but with the tongues removed to unload the prop

    Y are similar to X series but have 10% more pitch

    X5 are similar to X4 with medium lift and more pitch

    X6 similar to X4 and X5 with medium-high lift

    14 are medium-high lift commonly used for hydros

    16 are high lift props for riggers and hydro's

    17 are the highest lift prop for riggers and hydros

    P7 are similar to 17 series but more rake and slightly less lift

    19 are high lift for riggers and hydro's

    V9 are moderate lift and high pitch suitable for riggers, hydros and SAW racing

    20 are moderatley high lift with high pitch suitable for riggers and hydros

    21 are high lift for riggers and hydro's

    22 are high lift, highest pitch surface drive only good straight line speed

    I thought y all might find this helpful JOHN SS CUSTOM FUEL TANKS 
     
    Last edited by a moderator: Feb 6, 2019

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