Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Vortex Generators on a Standard Props.

Discussion in 'Pro/Adv Discussion' started by philip1652, Nov 6, 2015.

  1. philip1652

    Joined:
    Jul 21, 2015
    Messages:
    27
    Likes Received:
    12
    After 30 minutes filming in dusk today to capture some thunderstorms, did a lot of bug smashing.

    Cleaning the props I noticed some interesting design features.

    On the standard props, just inboard from the point of maximum chord, and also maximum camber on the leading edge are four small vortex generators.

    Almost invisible, and very easy to "sand off" for those that insist on perfectly balanced props I wonder just how much these almost invisible design features affect flying qualities.

    As a former airline pilot I am very conscious of just how much these small things can affect efficiency and flying qualities of an aircraft. next time you go flying in a jet look out the window and you will see them.

    Do these exist on every DJI prop?
     
  2. volito

    Joined:
    Mar 6, 2015
    Messages:
    69
    Likes Received:
    12
    Location:
    USA
    I have DJI stock 9450 props (on a P2V+). The only possible vortex generators on these are the part number and DJI logo.
     
  3. philip1652

    Joined:
    Jul 21, 2015
    Messages:
    27
    Likes Received:
    12
    Your right! Had a close look under bright light, and that is exactly what they are!
    Maybe thinking DJI are more advanced in design than they actually are, however there is a very exact science on propeller/wing design (propellers are just wings that go round and round) and camber, chord, Angle of attach are critical.
    I often wonder what decision making process goes into the final production design, or whether it is just whether it looks sexy!
     
  4. GreggC

    Joined:
    Oct 14, 2015
    Messages:
    259
    Likes Received:
    71
    Location:
    Rio Rancho NM
    I fly the DJI Black Carbon reinforced 9450 props, when I get home Ill see if these props have the vortex generators.
    A couple comments on the OP post;
    I insist on perfectly balanced props, IMO a balanced prop is critical, reciprocating mass has got to be balanced...period.
    When balancing a prop NEVER sand material from the face of the prop, the face is an airfoil and should not be disturbed, sand from the back only.
    To answer the question "I wonder just how much these almost invisible design features affect flying qualities"
    IMO vortex generators are very important, what they do is create a boundary layer on the surface of the airfoil, this boundary layer aids in keeping the air on the surface of the airfoil making the prop / wing / spoiler ...ect far more efficient.
    So if indeed these props are designed with vortex generators there is a reason they are there.
     
  5. BigAl07

    BigAl07 Moderator
    Staff Member

    Joined:
    Jan 5, 2015
    Messages:
    2,362
    Likes Received:
    1,268
    Location:
    Western North Carolina
    Good morning Phillip.

    I too greatly realize and appreciate VG's but due to the small size and scale of our props I seriously doubt DJI has put the time, $$, and effort into adding these to the prop. If I were a betting man I'd bet it's simply the prop identifiers etc and no more than that.

    I'm not saying it can't help but the net benefit on such a small scale would be negligible is even detectable.

    Remember the air these "airfoil" are operating in is so turbulent and nasty because they are following directly behind another one that I don't think they would have a chance to do any real good. Where-as a wing slicing through the air has a majority of relatively "clean" air to work with.
     
  6. olof Ekbergh

    Joined:
    Sep 30, 2015
    Messages:
    252
    Likes Received:
    137
    Location:
    Mt Washington Valley
    In my experience most of DJI's props are very well balanced. Out of 8 P3P props I only sanded 2 lightly (on the back side) hubs have all been good.

    On larger props like 15" on the S800 etc. I often have to sand quite a bit and add some CA to the side of the hub as well. Having these sometimes not so small CA bumps on the side of larger props anyway has never caused any problem, though I bet they do cause some vortexes. Of course this is right at the hub where the prop spins slowest and produces the smallest amount of lift.
     
  7. GreggC

    Joined:
    Oct 14, 2015
    Messages:
    259
    Likes Received:
    71
    Location:
    Rio Rancho NM
    My experience with the 9450 Carbon Reinforced props is different, every single one needed to be balanced.
     
    Mr.Spock likes this.
  8. Phantom12014

    Joined:
    Sep 15, 2014
    Messages:
    76
    Likes Received:
    17
    I have the carbon reinforced props and I never balanced props before ive always been a little scared that id mess it up. Any suggestions on how to balance properly?

    Sent from my SM-N910P using Tapatalk
     
  9. Fplvert

    Joined:
    May 28, 2014
    Messages:
    1,559
    Likes Received:
    708
    Location:
    Southern Idaho USA
  10. Mr.Spock

    Joined:
    Sep 14, 2015
    Messages:
    369
    Likes Received:
    67
    Location:
    UK
    I sanded them off with soft sanding sponge my wife uses to polish he nails. I have the DJI CF props too 2 out of 4 are slightly unabanlced
     
  11. Mr.Spock

    Joined:
    Sep 14, 2015
    Messages:
    369
    Likes Received:
    67
    Location:
    UK
    Where are these vortex features please can someone put a picture up? I cant find them
     
  12. Meta4

    Meta4 Moderator
    Staff Member

    Joined:
    Jan 8, 2014
    Messages:
    7,767
    Likes Received:
    3,478
    To save anyone looking for them .....