On Wed, 2008-11-05 at 23:06 -0600, Curtis Olson wrote: > On Wed, Nov 5, 2008 at 9:21 PM, Ron Jensen wrote:
> The new airframe has a *really* nice blended body center section. The > wings plug in are are replacable. We have experimented with a couple > airfoils, different wing areas, wing sweep, and different vertical > stabilizer configurations. We also shaved about 2 lbs of weight for > the newest airframe which is significant since that is equivalent to > about an hour's worth of battery. Hmm... I've been playing with xfoil a little trying to hone my aerodynamics knowledge... I've also been working with DATCOM+ a bit for the same purpose, but DATCOM isn't good for low reynolds numbers, so I don't know what it would do in this application... What Reynolds number are we looking at? Somewhere between 5e6 and 1.5e7? > If anyone cares, the wing span is just under 8' now. It's constructed > of foam core covered with carbon fiber, kevlar, and fiberglass > depending on the strength/weight needs of different portions of the > airframe. The all up weight with autopilot, camera, and 1 hour worth > of battery is about 9 lbs. It is capable of being fully "marinized" > and is able to land in the ocean and all the important bits are sealed > and protected from salt water. It cannot take off from water, but > instead is designed to be hand or catapult launched. We over > engineered it to be extremely strong and robust. Operations at sea > are very hard on equipment and this airframe needs to stand up to > abuse. In our field test last spring, on one recovery, the small boat > that was picking it up out of the ocean was lifted up out of the water > by a wave and slammed down on top of the wing. In another situation > we almost had a 240' NOAA ship run over it. We can't make it out of > 1/4" steel, so this is the next best thing. :-) Remember, I modeled the Oscar Sette... And followed the mission on the blog... > Top speed is hard to say and depends very much on power and prop. We > are shooting for efficiency and longer flight times, not high end > speed. However, I do have data from one flight clocking the wing at > about 88 kts in a dive. Later I put on a speed prop for fun and I > know I was hitting even higher number, but I don't have any hard data > to say exactly how fast. Typical cruise speeds under autonomous > control are in the 35-50 knot range. > We don't have rudder control, but the airframe is capable of rolls, > loops, inverted flight, and most of the basic aerobatic things a > person might want to do. Duplicating your flight control system in JSBSim is what I'm most interested in... You only have one control surface per wing so I assume they must function as elevons (both elevators and ailerons). Do you simply sum the aileron input and elevator input? Is pure elevator or pure aileron input capable of driving the elevon to full deflection? > This serious aspects of this project are sponsered by NOAA. Hopefully that doesn't make design too super-secret. > What was your question? Oh yes, certainly if someone was interested > in making some tweaks and updates to the 3d model, that would be > awesome. I've learned how to do a few things in my life, but 3d > modeling is something I've always really struggled with. It looks like a fairly simple model... But none of your pictures has anything I can use for scale... Any hints like root chord, tip cord and semi-span (the length of the removable wing panel). Maybe body width and length... > And if there are ways to improve the flight model and make it closer > to the real thing, then please, I'd love to work with you on that. The better the flight model, the better the autopilot, right? > I'm nearing the point where I could start to think about doing some > automated/consistent flight testing to hopefully generate high quality > data (versus just flying around aimlessly and collecting that data) > > > Please don't kill yourself! We need someone with write access > to maintain the CVS server ;) > > How does that saying go? "Someone cracked my password, so now I need > to come up with a new name for my dog." I solved that problem... I have two dogs! Ron ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Flightgear-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/flightgear-devel
