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Drag points... just a random measurement number Jundroo made up, or an actual real life unit?

234k jamesPLANESii  4.4 years ago

What is drag actually measured in? It seems like a pretty random number that seems not to have any meaning, but everything else in SP is based on a real life unit.
So what is it?
I guess knowing this could be useful for making designs more realistic.


Have a photo I took in February

Okie

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    9,103 ZWLenning

    My hypothesis is that drag points are irrelevant in relation to the unit drag is measured in. This image probably explains it... Ish. Each point has a value of drag, and that value is too high I think.

    4.3 years ago
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    6,361 11qazxc

    i don't know about simpleplanes, but in real life it does. @jamesPLANESii

    4.4 years ago
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    Woah. That actually works? :D @11qazxc

    4.4 years ago
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    6,361 11qazxc

    https://en.wikipedia.org/wiki/Drag_count
    The drag coefficient is used to compare the solutions of different geometries by means of a dimensionless number.
    A drag count is used as a more user-friendly measurement(bullshit) as the coefficient of drag is usually much less than 1. A drag count of 200 to 400 is typical for an airplane at cruise.
    A reduction of one drag count on a subsonic civil transport airplane means about 200 lb (91 kg) more in payload.(not really)
    /
    @Starbound
    v=83(m/s)
    p=1.225(kg/m^3)
    fd=6000(n)
    Dcd=10^4×(2×fd/(p×(v^2)×a))
    a=15.6088(m^2)
    Dcd=911.00226
    fd=0.5×p×(v^2)×cd×a
    cd=0.0911002
    /
    in result:
    velocity v=83 m/s
    gas density p=1.225 kg/m^3
    reference area a=15.6088 m^2
    drag points 911.002
    coefficient drag cd=0.0911002
    drag force fd=6000 n

    +2 4.4 years ago
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    I think it’s to do with the physics updates per frame, and the frame rate is much higher in slow motion @Zanedavid

    4.4 years ago
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    9,361 Zanedavid

    I also have so many of these types of questions too, like for instance why are the physics different in slow motion or fast forward? Or how accurate is the Collision damage? Etc

    4.4 years ago
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    Yup @ChiChiWerx

    4.4 years ago
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    12.1k Starbound

    Did a simple test with a jet plane with symmetrical airfoils, here's the results:

    Drag points: 911
    Thrust: 6000 N
    Top speed reached at sea level (IAS): 83 m/s
    Thrust power assuming constant thrust: 6000 * 86 = 498000 W = 498 kW

    The thrust power should be equal to the work done by the incoming air,
    but I have no idea how to use this number to arrive back at 911. Obviously this is as simple as it gets and there are a lot more variables in reality, so the answer is probably in that. The wing area and weight of the aircraft turn out to play a role as well even though their effects are not reflected in the number of drag points.

    4.4 years ago
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    30.3k ChiChiWerx

    Arbitrary, completely arbitrary. Do you realize that since there’s no actual air in SP, just calculations which simulate the effects of a body or wing moving through air, that drag is produced by parts which are submerged into other parts or out of direct airflow behind other parts?

    +1 4.4 years ago
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    1,120 WrongFlyer

    Actually, I’m pretty sure it’s Big Macs sold squared... but I could be wrong. @BaconAircraft

    +2 4.4 years ago
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    2,188 1gecko

    D r a g
    R a c e

    +1 4.4 years ago
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    measured in units of number of fathoms times cubic square feet of agent orange dropped per iraqs invaded raised to the muzzle velocity of an AR-15 per vietnamese farmer in a cubic kilometer of a jungle per yards times big macs sold cubed... obviously.

    +9 4.4 years ago
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    162k spefyjerbf

    In my experience it’s what @AstleyIndustries said. Cd, or coefficient of drag, tells us how the aircraft’s drag force varies with speed.
    .
    Edit: the drag coefficient is used in real life. I would imagine that drag points are a computational way of giving your flight model a drag coefficient of some sort.

    4.4 years ago
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    its more of a measuring unit-less value , just match everything with the real thing , and adjust drag accordingly

    4.4 years ago
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    19.3k Axartar

    nice photos. oh drag yeah

    4.4 years ago
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    I imagine it acts like some kind of drag coefficient

    4.4 years ago
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    32.3k CRJ900Pilot

    I've had the same thing bugging me for a while. From testing many planes, that number should fall in the 2000-3000 range for realistic performance

    4.4 years ago
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    they can be exchanged for bitcoin

    +15 4.4 years ago
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    Dev WNP78

    Knowing the SP drag system it's probably in a unit like cobwebs per ancient scripture. I don't think number-matching to a drag value is feasible. I think your best bet for performance matching is to match the other characteristics like wing area, mass and thrust, then adjust drag scale experimentally to match characteristics like glide ratio or "top speed" (presuming this is limited by power and not structure).

    +17 4.4 years ago
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    16.9k YourWife

    big agree

    +1 4.4 years ago