Current News
Speaking of hardware updates, how about some photos?
The main compartment is missing only a receiver and autopilot, but here is the final arrangement:
.
The green board is the RxMux by Jay Francis which allows switching between the manual receiver control and onboard autopilot control. While I did some homebuilding a while ago, the commercial product is far superior and lighter. And it works EVERY time. The silver boxes are the Skymelody variometer setup. This will be the thermal sensing and will be combined later with a GPS signal to get an overall idea of what thermals look like on the East coast. On the left are two locking switches; the batteries mount on velcro behind the switch tray.
Next let's look at the tail servo arrangement:
You can see the elevator and rudder servos near the aft (right) of the wing opening. The elevator pushrod is a carbon fiber tube, making for very slop-free control. To ease stresses on the rudder servo when landing in grass, the rudder uses a pull-pull cable setup. The cables can stretch slightly to reduce risk of stripping a servo gear when the rudder gets deflected by contact with the ground; however, the aero loads are small by comparison, resulting in solid control while flying. If rudder flutter is a problem, the pull-pull can be switched to a stiff pushrod setup. Also see the foam vibration isolation mounts for the autopilot on the left beneath the wing wiring harness.
Last, the wing servo installations:
After much debate how best to mount servos in the wing, I finally decided to glue them in with Household Goop. Having never used the product before, I was reluctant, but some folks practically swear by it. Let the glue set up for at least 24 hours and it cures hard as a rock. I scored the back of the servo with an X-Acto knife and roughed up the inside of the wing skin with heavy sandpaper before bonding. I am happy to report the rumors are true: the servos are quite securely mounted ... HS-5125 for the ailerons, HS-422 for the flaps.
Hopefully next entry will include images from the maiden flight tests. I have a receiver in the mail currently. Once it arrives and I can give the aircraft a full shakedown and range checks, I should be ready to take it out to the field!
I have a new algorithm that locates an updraft, then will orbit at the optimum radius inside it. I have some preliminary simulator testing which shows extremely promising results, but I am short on the funding needed to fly it.
While it may look like I am fairly set on resources since the vehicle is going together smoothly, there are a few outstanding items still needed. Namely, the Piccolo source code is being pursued at the moment. I am still working out the details to get a loaner Piccolo and ground station. Once I get these two major items, I will need some random other support equipment such as cables or antennas or batteries. Also, I would like to get/build a winch so I can launch the vehicle without needing to travel an hour and a half to an established glider club.
One other item I thought would be fun to involve the public is a web-viewable vehicle position posted on a google-maps interface! This means you (anyone on the web) can watch the vehicle's progress in real-time when I make the record flight attempts! I found a product that uses the Automatic Packet Reporting System (APRS) on the HAM band and some freeware for mapping. Anyone interested in donating one? It is called the MicroTrack 300. More information about the online mapping can be found here: http://wa8lmf.net/aprs/index.htm. This link will track a particular callsign: Add Comments
- I've been emailing Dryden and getting some information about the NASA thermalling plane (ironically the same airframe I was hoping to use). So far I have over 350 pages of reading to know like the back of my hand.
- I've been searching for project funding. I have a few leads, but nothing secured yet. If you are interested or know someone who is interested in funding me, please contact me.
- I'm applying for grad school and fellowships currently, as well as working really long hours on a senior design project for NCSU's Aerospace Engineering program. This is the primary reason I haven't made progress in a while.
News of the physical type...
- The GPS carrier card is being shipped off. My breakout board worked, but Alex offered to make a nice PCB for me. I'll post pics and the project will probably revive a bit after I get it in the mail.
- A new UAV sensor package is in the works, called Flightstix, a soon-to-be product of the Aerial Robotics Club. More on that as it progresses, but let's just say if it works, I can simply concentrate on programming the controller.
Done! Though it wasn't my circuit, I did get a working board from a generous modeler named Jay and who is now selling a limited number of his switches on RC Groups, which you can see here: link. I put it in a box for Aerial Robotics, but it could be smaller and lighter for my application.
So now that the airplane is flying, onward and upward to working on the GPS and BX-24 integration again. As of now, the BX-24is now receiving serial communications from the GPS receiver. I have example code to parse the NMEA GGA sentences into position and altitude, though I have yet to walk outside to test with a good GPS lock. Hanging my electronics out the window juuust wasn't enough to find four satellites. More to come soon.
