Adding a Foot of Wing Span to Left and Right Wings in a Piper Super Cub

Discussion in 'General Experimental Aviation Questions' started by Southron, Apr 22, 2013.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Apr 22, 2013 #1

    Southron

    Southron

    Southron

    Well-Known Member

    Joined:
    May 5, 2012
    Messages:
    86
    Likes Received:
    5
    Location:
    Eatonton
    What would be the result of adding 12 Inches to both the Left and Right Wings when building the wing of a Pazmany PL-9 Stork? I figure that it would reduce the wing loading per square foot of wing, slightly increase drag and probably require that the wing spar be strengthened. Any suggestions or insights would be appreciated.

    THANKS
     
  2. Apr 22, 2013 #2

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    11,824
    Likes Received:
    2,242
    Location:
    Port Townsend WA
    Piper Super Cub or Pazmany PL-9?

    In either case, the effect may be small ....but any change has a consequence.
    For example, yaw stability would be less, perhaps a 12" tail extension would help.

    But this adds weight, changes the CG..... You get the idea.
     
  3. Apr 22, 2013 #3

    autoreply

    autoreply

    autoreply

    Moderator

    Joined:
    Jul 8, 2009
    Messages:
    10,732
    Likes Received:
    2,540
    Location:
    Rotterdam, Netherlands
    A much weaker (or much stronger required) wing spar. A few dozen percent easily. A proportionally less effective rudder, more weight etc. In other words, why bother when you have a good plane?
     
  4. Apr 24, 2013 #4

    Battson

    Battson

    Battson

    Well-Known Member

    Joined:
    Jan 30, 2012
    Messages:
    610
    Likes Received:
    96
    Location:
    New Zealand
    Noticibly shorter takeoff distance and higher gross weight limit are the typical benefits of wing extensions, but you lose airspeed and roll rate - this is based on the many years experience gained from the many options available for wing extensions which available on the open market for GA aircraft, and are widely used....
    Typically this includes strengthening the spar, but no tail mods are necessary, and controls are the same except roll rate is reduced slightly (typically the ailerons are not extended). I have seen it fitted to many models of Cessna, Super Cub, never a PL-9.
     
  5. Apr 25, 2013 #5

    Kristoffon

    Kristoffon

    Kristoffon

    Well-Known Member

    Joined:
    Sep 4, 2009
    Messages:
    348
    Likes Received:
    20
    Location:
    Brazil
    The Osprey-II I'm building has an option where the designer allows extension of wingspan by two feet by simply building 2 extra wing ribs and extending the spars. It's not a very similar plane but it should be good to give you an idea of what to expect. You can find specs on the plane here.

    According to the designer the spars built in that way are still good for the 4.5G of loading on the original project, but then again they were overbuilt originally.

    From the report, flight testing with the same engine and weight at same power setting shows an increase in ROC of 100-150 fpm, stall speed reduced 3-5 mph, top and cruise speeds reduced by 4-5 mph.

    FWIW I'm building mine with the original wing.
     
  6. Apr 25, 2013 #6

    4trade

    4trade

    4trade

    Well-Known Member

    Joined:
    Nov 1, 2010
    Messages:
    527
    Likes Received:
    71
    Location:
    Lahti/Finland
    You probably achieve same amount of lift without extension, if you add flaperon mechanism in your aileron. Super Cub people do it for STOL purposes. Cheaper, lighter and require only small modification in your system.
     
  7. Apr 28, 2013 #7

    Mad MAC

    Mad MAC

    Mad MAC

    Well-Known Member

    Joined:
    Dec 9, 2004
    Messages:
    411
    Likes Received:
    167
    Location:
    Hamilton New Zealand
    Structurally it would be easier & lighter to add 24 in to the width of the center section wing pickups, then you are changing the piece of structure that will see the new higher loads.
     
  8. Apr 29, 2013 #8

    Battson

    Battson

    Battson

    Well-Known Member

    Joined:
    Jan 30, 2012
    Messages:
    610
    Likes Received:
    96
    Location:
    New Zealand
    The concensus on Super Cub flaperons seems to be they are more dangerous than helpful in anything less than perfect conditions. Not my experience by any means, but those I've spoken to who have experience seem to say the same things. The stall becomes too sharp and unpredictable to fly close to it.
     
    Last edited: Apr 29, 2013
  9. Apr 29, 2013 #9

    dino

    dino

    dino

    Well-Known Member

    Joined:
    Sep 18, 2007
    Messages:
    586
    Likes Received:
    81
    Location:
    florida
    Maybe it could be registered as a motorglider.

    Dino
     
  10. Aug 7, 2013 #10

    S22 Bushmaster Amphi

    S22 Bushmaster Amphi

    S22 Bushmaster Amphi

    New Member

    Joined:
    Aug 7, 2013
    Messages:
    3
    Likes Received:
    0
    Location:
    Tisdale/Saskatchewan/Canada
    My Super 22 Bushmaster was a PA22 before 5 ft were added to the wingspan, and 23.5 inches added to the aft fuselage, but the wings are not Piper. It does make for a more rudder controlled aircraft that gets off the water a lot better. Additional vertical stabs were added to the tail plane to offset the large vertical surface of the floats in front of the center of lift. VGs were added to the tail feathers to increase control at low speeds. 180 hp CS prop requires 60 gal fuel in wings. DSCF3862.jpg
     

Share This Page

arrow_white