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Recent content by PaulPounds

  1. PaulPounds

    Pure teetering rotors - associated problems

    Greetings all, I'm developing a UAV helicopter with a special construction that puts the centre of gravity on the plane of the rotor. This allows me to eliminate torques due to the H-force and horizontal component of the tilted thrust vector. I'd like to make it a pure teetering rotor...
  2. PaulPounds

    Rotor speed dynamics

    Greetings all, My latest work has involved finding the speed response of my aeroelastic rotors when a step is applied to the motor current. Because my robot heli is so small, we change thrust by varying rotor speed. What's more, we change attitude by producing torques by varying the...
  3. PaulPounds

    Hub Springs

    Thanks for the tip about the vibration - that might go some way to explaining some control problems we'd been having that went away when we removed the springs. As it turns out, I don't think we will use the springs at all because our stability model shows we don't need them.
  4. PaulPounds

    Hub Springs

    Greetings all, I recently ran across the section on hub springs at the Synchrolite page: http://www.synchrolite.com/1230.html I too looked into hub springs for my four rotor helicopter (though I didn't know anyone else was working on them at the time). I was using the springs to...
  5. PaulPounds

    Someone was interested in aeroelastic model simulation code...

    Will do - I make no claims that this thing is actually accurate/user-friendly/correct/useful/non-fattening. -Paul
  6. PaulPounds

    Someone was interested in aeroelastic model simulation code...

    The total file size is 120k, including the main m-file, auxillary m-files and some polar data files from X-Foil at a range of Reynold's Numbers to get you started. -Paul
  7. PaulPounds

    Dynamic inflow speed

    Greetings all, Here's a problem I've been working on for a bit - what do people know about the rate of change of the inflow through a rotor? I have a weird case where I'm slowing down electric motors that directly drive my rotors. These are fixed pitch blades, so changing the...
  8. PaulPounds

    Someone was interested in aeroelastic model simulation code...

    The program is all cleaned up - I just need to find somewhere to stick it online. Sorry for the delays! -Paul
  9. PaulPounds

    Someone was interested in aeroelastic model simulation code...

    Greetings, A while ago, some people expressed interest in the aeroelastic blade simulator I was coding for my rotor design work. I've spoken to my supervisor about it and it's ok to distribute it. If people still want it, I'll tidy it up and put it in a form that folks can use. It's...
  10. PaulPounds

    Rotor ground effect oscillations and control

    Greetings all! It's been a long time since I've had a chance to check out the forum, so I need to catch up. While I'm going through the archives, here's my question du jour: I have a rotor that is a drive unit for this four-rotor robot I'm constructing. To design the attitude...
  11. PaulPounds

    Aeroelasticity... counteracting blade twist

    Our blades are fixed-pitch, so I'm not sure they'll have that problem. Blade sweep isn't something I've considered, but it sounds intruiging. I'll have a look into it - thanks! -Paul
  12. PaulPounds

    Flat plate airfoil polars for stall

    Everyone knows about flat plate airfoils, but no one would ever use one, right? Well, I've got a very thin airfoil rotor operating at high AoA, so I reckon it's performance can't be far off a flat plate at and past stall. Can anyone direct me to accurate polars of flat plate behaviour at stall...
  13. PaulPounds

    Aeroelasticity... counteracting blade twist

    Ah, I'd do that in a flash except for two reasons. 1. It's buggy as hell and I'm not even sure the results it gives are meaningful 2. It's probably the IP of the uni at which I work... they have this thing about 'anything you produce blah blah blah is ours, plus your immortal soul'. Mind you...
  14. PaulPounds

    Aeroelasticity... counteracting blade twist

    Yeah - I have this crazy dream of free engineering tools for non-commercial use, like RC aircraft and scale modelling, but I don't think I'll ever see it. Still, the thought of being able to design an airfoil, then a rotor, then the whole craft on my PC is a seductive thought. For now, I'll...
  15. PaulPounds

    Aeroelasticity... counteracting blade twist

    Uh... wellll, nothing quite so fancy as that! My 'simulation' is more of an emulation. I use an iterative algorithm coded in matlab to calculate the moments, lift and drag on each radial station of the rotor blade. It then uses these values to figure out the resultant rotational velocity of...
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