CriCri Ultralight?

Discussion in 'The light stuff area' started by alexkmmll, Dec 10, 2010.

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  1. Dec 10, 2010 #1

    alexkmmll

    alexkmmll

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    I was recently sketching some Ultralight designs when I remembered the CriCri. After doing some research, I thought it might be fun to to an ultralight in a similar design for simplicity.
    In order to convert it to an ultralight, you would probably have to:
    -Increase wing Chord and have a thicker wing to create drag+lift
    -Use Dacron instead of Aluminum for skin
    -Smaller engines possibly (6hp x2 too little?)

    Does this seem like it would work to get it to ultralight standards, or if it would work at all?
    (Much help is appreciated)
     
  2. Dec 10, 2010 #2

    PTAirco

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    You would need vastly more wing area to qualify as an ultralight. And you cannot simply omit the skin from the wings; there is nothing else to give them torsional stiffness. It would not be practical as a Part 103 ultralight.

    Designing a small, minimum size airplane is a lot easier than designing a strong and practical ultralight.
     
  3. Dec 11, 2010 #3

    Bigorneau

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    It should be interesting for you to go to the site of "Luciole" from M. Colomban (designer of CriCri and Luciole).
    Luciole may be built as ultralight or aircraft and for very small budget.
    with small engine
     
  4. Dec 11, 2010 #4

    autoreply

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    The Americans are discussing the US definition of an ultralight (FAR 103, 24 kts stall, 110 kg empty), not the European (EASA, 35 kts, 300 kg MTOW). The weight isn't such a problem as the stall speed, compared to an ULM, the US ultralights need 2.13 times more wing area. That's why PT doubts the practicality of the Cri-Cri as ultralight.
     
  5. Dec 12, 2010 #5

    travis1990

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    If I were you i would just scale the design up until you got the right wing area.

    You'll need at least 120 sq.ft. of wing area.
    Cri cri's wing area = 33 sq.ft.
    120/33 = 3.64
    Square root of 3.64 = 1.9
    So scale it up %190

    Of course you'll have to redo the aerodynamics/stability analysis because that doesn't "scale up".

    P.S. you'll need way more than 12hp probably about 30-40hp.
     
  6. Dec 13, 2010 #6

    topspeed100

    topspeed100

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    12 hp would be enough if..the plane was single engine ( and very lite ). A twin usually needs to fly on one engine alone thus needs minimum 20-30 hp if aerobatic.

    Human powered planes fly at 0,7 hp..and some solar powered Gossamers around 3-6 HP.
     
  7. Dec 30, 2010 #7

    Catocala

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    Hi Alex!

    I am not sure that transforming a cricri into an ULM is a good idea. THis extremely particular plane is typically the result of a very smart trade-off. Furthermore, the structure works heavily with the skin...
    Furthermore furthermore, I was told that european designers are very reluctant to sell the blueprints to US due to juridical implication (as far as I know, US laws considers the designer as being fully responsible. In Europe, it is the builder which is responsible...
    That said, the cricri is a funny and splendid machine...(cf youtube...)
    Hope you will find a good project!

    Catocala
     
  8. Dec 30, 2010 #8

    topspeed100

    topspeed100

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    I know a CriCri in Finland that was purhased from Canada. It crashed immediately since the original builder had put very heavy engines on it and it instantly stalled at take off at very high speed after take off..or numerous take off attempts. Luckily no one got killed. It was nose heavy.

    Is it more free to build planes in Canada than in USA ?
     
  9. Dec 30, 2010 #9

    Dana

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    No, the US regulations are about as loose as it gets. Unfortunately, the US lawyers are also as loose as it gets...

    -Dana

    Cause of crash: Inadvertent contact with the ground.
     
  10. Dec 30, 2010 #10

    Topaz

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    I sense another signature line being added to Dana's list... :gig:
     
  11. Dec 31, 2010 #11

    Starflight

    Starflight

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    TS100- Canada's ultralight building "codes" are really quite adaptable. Our pilot permits are the restrictive collars :p
    Our launch weights (empty+fuel+BRS) are based on a wing area formula which can grow to 165Kg(364#) at 160 sq.ft(15 sq.m.).
    The minimum size/weight, based on 10 sq.meter wing, would equal FAR 103 at 253#(115Kg). We are not restricted to how
    much fuel we can carry or how fast we can make it go! Only, it has to land at under 45mph(70kmh). Original designs are AOK :O)
     

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