F1A Stab incidence during Tow and Launch

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    3.. Should one keep the circle tow stab incidence during the pre
    launch acceleration phase for extra line tension or should one lower the
    stab for extra speed? I plan on circle towing with extra wash-in on the
    inside wing and extra stab incidence to compensate for the effect of the
    towline drag and give a tight circle with a realistic sink rate for
    assessing the air the model is in. Should I keep the extra stab
    incidence during acceleration to help get good line tension and rely on
    this to pitch the model up at release or should I take it out to get
    extra speed and have a quick blip of up to pitch the model upwards on
    release? (I presume personal timing sequences are top secret but if
    anyone is prepared to give me some suggestions they would be very
    gratefully received.)

    Niel Murray posted by Jim Parker


    3. Stab incidence on tow question – there are lots of opinions on this
    one! For circle tow kick up the stab above the glide setting until it
    just starts to become stally while on the line. Being right on the edge
    of the stall is good for making the model turn quick on the line, for
    calm conditions a little less incidence might be good. I ususally use
    the same position for straight tow, although in wind lowering the stab
    during straight tow closer to the glide position can be good to lower
    the pull and help the steerability. For maximum launch speed when the
    model is unlatched and accelerating, there are some people that lowering
    the stab is good to lower the drag and increase speed. However I
    believe that it is the pull on the line that generates the speed and so
    I put the stab where the model will pull the hardest which is usually
    more up than glide position, or about the circle tow position. You can
    try adding more and more incidence to generate more pull, but there is a
    point of diminishing return where the model won’t fly right anymore.
    One trick tried by some super tech nordic guys like Allard V or Rene
    Limberger, is to have the stab gradually increase in incidence during
    the acceleration, the theory being that more incidence is needed just
    before launch to counter act the loss of pull that happens when the
    model gets overhead. Those guys can comment on that. I definitely
    believe that it is good to have extra incidence in the stab before
    launch to pitch the model up immediately and quickly, rather than trying
    to blip the stab after launch.


    .. Should one keep the circle tow stab incidence during the pre
    launch acceleration phase for extra line tension or should one lower the
    stab for extra speed?
    Depends on the wind. M&K models have the option of changing the tail
    incidence when the hook is fully extended (OLA). If it is calm this can be
    used to increase incidence to maintain tension. If it is windy you can
    reduce tension in order to get more speed without excessive tension.
    You do need considerably more than glide incidence for circle and straight
    One of the big advantages of the electronic bunter is the ability to reduce
    incidence for the “cruise”. To get the best height the model should pitch up
    quickly to vertical (pitch up incidence is about a degree or so more than
    tow incidence and tow incidence is about 2 deg more than glide). As soon as
    the model is vertical incidence is reduced to a degree less than glide to
    prevent the model looping over onto its back. With a mechanical model the
    climb has to be done at the tow/pitch up setting and hence the model will go
    past vertical.

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