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...
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...
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.
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...
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
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...
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...
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...
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
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...
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...
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...
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...
Actually... my calculations for tip weights look promising. Maybe it's not so impractical after all.
Can anyone direct me to a good source on calculating tip-weights?
-Paul
I've thought about tip-weights, but the problem is that it's difficult and dangerous to put weights on the tips (they are extremely thin). Furthermore, I want to keep the Lock number down, as this does good things to its passive stability.
I can't add tip sweep at this point, as that would...
Here's something topical for those following some of the work being done in aeroelsticity.
The rotors I've been working on for my robot helicopter are tremendously thin and seem to be twisting something awful. I've put together a computer simulation of the blade-twist/rotor speed system and it...
Right, so the Dragonfly doesn't have chord-symetric airfoils, or even reverse-flow airfoils then?
Since the dragonfly is intended for high speed flight, it makes me wonder if it would be more practical to use stopped-rotor reverse flow airfoils for something like a glider. Of course, it would...
That would make sense if you were using the wing as a rotor during forward flight - would that work if you were using stopped rotors?
One disadvantage I thought of recently was low stall angle. A sharp leading edge would make the flow seperate right at the front of the airfoil, much like a...
