The Game’s Afoot!

Feb 19, 2011

I managed to get myself a mentor. I posted a few questions over on DIYDrones and he was the only who really took time to encourage me and help me figure out what mistakes not to make. As it turned out, I had the wrong plane, the wrong GPS, the wrong xBee radios and was about to go to the wrong place to buy the various autopilot parts. Martin, over at BYOD (Build Your Own Drone) in the UK took me under his wing <wink, wink. Pun alert> and set me straight on a few things.  I decided to go with an EasyStar airframe, abut then ran into it’s twin brother over at NitroPlanes. Called the Hawk Sky, it is the same dimensions, wingform, power and configuration as the EasyStar, except it has a bit more room inside than the EasyStar. It’s made out of the same foam construction too. It has the added value of being a Ready To Fly kit, with only minimal assembly required, most likely that means I have to install the wings, tailplane and landing gear. It has a 2.4GHz frequency hopping spread spectrum radio, which is good in areas of high interference. I can attest to having some sad occasions when my 27 and 72 MHz radio planes developed minds of their own due to interference.

Martin sells a kit at BYOD that is pretty much the majority of the autopilot in an assembled set for about $410 US. I will still need better xBee radios and a few other items to have all of the electronics, but the cool part is that a lot of work has been saved by available products. For instance, I can get a kit of the female to female patch cables that connect the autopilot to the R/C receiver. By going with the whole kit concept, I also get preprogrammed firmware and access to proven existing Arduino sketches to boot. For a novice, such as yours truly, this will no doubt save a lot of frustration.  I’m feeling kind of jazzed.  Okay, I’m a little bummed I couldn’t use the components I already had. But they were actually purchased with rolling autonomo0us vehicles in mind, and there’s no reason I can’t go back to using them that way.  I set a budget for my project at $1000. I think it’s going to be more than that, but I’ll give it a shot. Say four-ten for the boards, another one-thirty for the airplane, the radios will be about a hundred bucks —that over $700 right there.

In the end I will have a lot more invested in this hobby. In the end I will want to have a plane that can languish in the air for a couple of hours and carry a video camera that I have on a pan and tilt gimble. That’s going to be a lot of weight and no way I could put it on a plane like the HawkSky or EasyStar. In the end I think I will use a canard. Their ability to pack a greater load with a wider CG is very attractive to someone who wants to swing a 2 ounce camera around on a 1.5 ounce gimble. Plus aux radio to stream the video and permit real time aiming and operation of the camera while the autopilot does the flying.  The photo at right just shows what a canard is, basically a plane that flies bass ackwards. The little wing is in the front and the big wing is in the back. Industry legend Burt Rutan has championed the canard aircraft in many of his designs. I’m a great admirer and have built a couple of canard aircraft copying his design methods and been quite successful. I think I can build a canard with the ability to pack an 8 to 10 ounce payload on top of it’s battery pack(s). But, that’s another story; one that ends with me in bankruptcy and divorce. Right about now we’re talking autopilot.

I happen to be a card carrying member of the Experimental Aircraft Association. Not like that’s any mean feat; anyone who pays the subscription magically becomes a member.  My point here is that airplanes have been an important part of my life. I carry a commercial pilot ticket and have logged time in everything from Waco UPF-7 biplanes to a CitationJet. At least, I have that time in my logbook, not to say I’m qualified in some of the fancier fare I was able to finagle a ride and some right seat time in.  The most fun I ever had in an airplane I had in an old Aeroncas Champ. Actualyy it was called the Champion, but everyone call ‘em Champs.  It got to the point that I’f dlown old N81966 so many times that I no longer got in it, I put it on like a batman suit. I could make that plane do whatever I wanted, so long as I stayed within its placarded limits, with a safety factor. As a result, the most violent move I made in the plane was to do a snap roll.  Sure, loops and barrels for sure, the occasional hammerhead or four leaf clover, and immelmans, I did a lot of immelmans, I enjoyed myself in three dimensions.  I have a lot of time flying microlights too, especially the Microlite Eagle. Wouldn’t you know it was a powered canard hang glider. (I see a pattern here).  I got my introduction to the Eagle by a guy named George, wnd he traded me flight time in it for hopping up his motor and fitting a fatter prop to it.  I flew the crap out of it but I never got comfortable in it. There was something about swaying back and forth to help steer, climb or dive that put me off a little. I much preferred the Quicksilvers with their fixed 3-axis control. Much better.  The Quicksilvers weren’t canards though, they were –are– little high wings with conventional tail, and drives by stick and rudder.

Getting cancer, has taken away my ability to fly, but here I am making model planes that will go up to the altitudes I miss so much, and eventually allow me to attain the pilot’s perspective. Our bird’s eye view. Multiple Myeloma may be rotting away my skeleton, but I can still use my hands and brain and even employ a little hand to eye coordination when pressed. I figure if I can fly my other models (which flying real airplanes actually didn’t help much) then I should be much better a flier with an autopilot engaged.

UPDATE:  02/22/2011

Well, the Hawk Sky arrived and I unpacked it. So, here’s the review.

The Hawk Sky by Dynam is a typical low end foam aircraft. It uses the flexibility of the foam in thin areas as a hinge for the control surfaces, which I don’t like. I will reinforce those flex points with mylar tape. I may even fully spearate the ailerons, elevator and rudder completely and then reinstall them with appropriate hinges. The way they have it, I would expect a control surface failure before too much time went by. The wings install on the beefy side though. There are wood dowls (2) that penetrate the fuselage and plug into cylindrical holes drilled into the wing root. This makes for a pair of nice carry-through wing spars. Many models just trap the wing ends between plastic forms that are screwed through the wing to one another. I’ve had a couple of planes with this style wing mount fold up in the air when I loaded the wings a bit too much. This won’t happen with the Hawk Sky.  The radio equipment is lightweight and small, and there certainly appears to be enough room for the ardupilot setup. All servos are already installed because the plane is RTF, so the task will be to place the arduStuff at the CG.  The 2.4gHz transmitter unit isn’t the prettiest I’ve seen (Walker’s helicopter factory preffered units are pretty by contrast.)

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