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Favorite Moves

June 10th, 2003 12:00pm. RC

Very nice day at the field. I played with doing a kind of Immelman. Fun! My maneuver was a bit different. I did my 1/2 roll while in the vertical. That seemed like more fun at the moment.Today I felt much more connected to the plane than previously. This gave me a lot more control and smoothness than I’ve had in the past. I’m rolling better, managing power better, managing the exchange of altitude and speed better.

Favorite moves:

  • Launching, giving it full throttle and watching it climb directly away from me in a straight line, ascending at 20 degrees. It just gets smaller and smaller.
  • I was flying 45 degrees away from being into the wind and straight toward me. I noticed that in order to track correctly, the plane was actually side-slipping a lot. We don’t need no stinking rudder!
  • Standing in the middle of the field and having the plane zip around me like a loyal dog darting around in the grass.
  • Getting up to 250 feet, pointing the plane directly at me, building up speed and then bringing the plane straight up, right over my head. As it ascends, I roll. My view sees a dark line in the sky rotating around an axis. I then pull out and dart away.
  • Flying by low and slow, low and fast, low and really really fast out of a steep decent, low and really slo[crash!] oop! When it flies by, engine off, silent except for a “shhhoo” of air, I grin ear to ear.

Oh, I forgot to mention what I did on Sunday! I went to the Poconos field.  I watched just one Stick 40 combat. Zowie! They had to cancel the rest of the combat because moisture was tearing the streamers after just a few seconds in the air. I saw a plane on the ground rev into a fence, shooting 1/3 of a prop 50 feet over peoples’ heads and into the side of the truck. The fuselage of the plane was broken  in-two. Lastly, back at Great Meadows, I saw a 7′ wingspan pattern plane (?) do looping, rolling, flipping 3-D tricks that blew my mind. My jaw was literally agape! It looked like a sprite fluttering about, only this sprite was larger than me and weighed like 50 pounds. Earlier in the day, I was impressed with a biplane doing what looked like shoulder rolls. But this new stuff was in a class 3 times removed.

Oh, I also tried flying at a local unused baseball field. I can now tell you that I can just barely keep the Zagi flying in a little league baseball field. I can also tell you that it sucks to have to fetch a plane in chest-high grass. Personal note: That’s about the smallest field I think I could ever fly at.

Griping about Batteries, Lost a Prop

June 9th, 2003 12:00pm. RC

The old lead-acid batteries in my workshop aren’t cutting it. I think one cell is shot. The other three are probably good, but they aren’t large enough anyway. With these 4 6-volt sealed cells, I’ve only got 8 amp/hours at 12 volts. And I’m trying to charge a 1.1 and a 1.7 amp/hr pack… At their best, they’d be good for 2 chargings. And it’s just a big pain to keep monitoring my car battery charger –> 12v lead-acid batteries –> peak charger setup. It’s too easy to mess up.Since it’s just 15 minutes to the field, I want to charge my batteries at home. (a reasonable slow charge is 1 hour per battery or longer… times 2 batteries). If the field was 2 hours away, I wouldn’t have this issue, I could just charge in the car… but then I wouldn’t go, would I? I’ve been looking around and the best advice I can find on fast charging vs. slow charging (i.e. 3C charging (20 minutes) vs. C/10 charging (10 hours) is that “fast charging can put more of a strain on your batteries so they’ll wear out faster”. Well, if I’m in no rush, I’m happy to slow charge. But I feel uncomfortable leaving a charger pulling my car battery dry for 10 hours. One day that’ll leave my car battery dead and sulphated. I looked around for a good 12 volt power supply. I could rip one out of a computer… I hear that computer repair stores are a good cheap source. But I lucked out and found a 12 volt, 13 amp supply on eBay for $30, shipping included. That’s way better than the $30 -3- amp supply at Radio Shack. Well, it hasn’t arrived yet, so I’ll tell you how well it works when I get it.

I flew today. Well, not really. I had the Zagi up high at a distance and the prop fell off. I should have remembered that I had knocked the prop off the last time I flew on a rough landing… I had reved the engine -after- I was sliding along the ground and justifiably bumped the prop off. I had just stuck it on and flew again, but I should have fixed it with CA glue or something when I got home.

So, I coasted in, landed the Zagi and looked for the prop. No luck. I really really hate those little canals on the flying field (it’s on a sod farm)!! So I broke out the Firebird. No luck there either. Both control horn-holder-downer-thingies had broken, leaving me with no tail controls. I considered cranking it up and throwing it into the wind anyway. But refrained.

Griping about Batteries, Lost a Prop

June 9th, 2003 12:00pm. RC

The old lead-acid batteries in my workshop aren’t cutting it. I think one cell is shot. The other three are probably good, but they aren’t large enough anyway. With these 4 6-volt sealed cells, I’ve only got 8 amp/hours at 12 volts. And I’m trying to charge a 1.1 and a 1.7 amp/hr pack… At their best, they’d be good for 2 chargings. And it’s just a big pain to keep monitoring my car battery charger –> 12v lead-acid batteries –> peak charger setup. It’s too easy to mess up.Since it’s just 15 minutes to the field, I want to charge my batteries at home. (a reasonable slow charge is 1 hour per battery or longer… times 2 batteries). If the field was 2 hours away, I wouldn’t have this issue, I could just charge in the car… but then I wouldn’t go, would I? I’ve been looking around and the best advice I can find on fast charging vs. slow charging (i.e. 3C charging (20 minutes) vs. C/10 charging (10 hours) is that “fast charging can put more of a strain on your batteries so they’ll wear out faster”. Well, if I’m in no rush, I’m happy to slow charge. But I feel uncomfortable leaving a charger pulling my car battery dry for 10 hours. One day that’ll leave my car battery dead and sulphated. I looked around for a good 12 volt power supply. I could rip one out of a computer… I hear that computer repair stores are a good cheap source. But I lucked out and found a 12 volt, 13 amp supply on eBay for $30, shipping included. That’s way better than the $30 -3- amp supply at Radio Shack. Well, it hasn’t arrived yet, so I’ll tell you how well it works when I get it.

I flew today. Well, not really. I had the Zagi up high at a distance and the prop fell off. I should have remembered that I had knocked the prop off the last time I flew on a rough landing… I had reved the engine -after- I was sliding along the ground and justifiably bumped the prop off. I had just stuck it on and flew again, but I should have fixed it with CA glue or something when I got home.

So, I coasted in, landed the Zagi and looked for the prop. No luck. I really really hate those little canals on the flying field (it’s on a sod farm)!! So I broke out the Firebird. No luck there either. Both control horn-holder-downer-thingies had broken, leaving me with no tail controls. I considered cranking it up and throwing it into the wind anyway. But refrained.

What I Did on Memorial Day

May 26th, 2003 12:00pm. RC

My airplane is pretty. It is an electric airplane. I fly it in the air. I went to the flying field on Memorial Day. I flyed it there real good. ;-)

I had a very nice flying experience today due to a combination of improvements:

- I used careful throttle management and was very happy to find that I got about 15 minutes in the air. Previously, I got about 5 minutes in the air mostly WOT. I have seen several reports of people that get “10 minutes WOT” with a 1700 mah battery… Those claims sound dubious (at least from my experience). And it seems to be the case that since my battery was draining slower, it also offered up more juice before giving out. As proof, when I went out last week, I got 5 minutes of flight time and then my peak charger put 800 mah back in. Today, it put 1,500 mah back in during recharge!

Twice I had a problem where I launched at full throttle, went about 5 seconds and then the engine cut out. I still had elevon control. Apparently, the battery voltage dipped and tricked the ESC into thinking the battery was almost dead. :-( After another start, I was ok. I guess the think to do is just keep off the full throttle until the battery is warmed up… or maybe pre-warm it on the ground.

- I fiddled with the CG, not to much effect. Though I’m going to put some more velcro in the tray so I can move the battery around more.

- Last night I reironed the Oracover. It had gotten crinkled up after some crashes. I think it helped with the aerodynamics. I’ve also got an issue with… ok, I’ll just come out and say it… when I first ironed it on, I didn’t take the protective film off. It stuck kinda-well, so I left it. It’s still on. Of course I’ll redo it eventually.

- I got in some inverted flight! Woo hoo! Unfortunately, I couldn’t quite maintain altitude, even by pushing all the way forward on the stick and all the way forward on the trim. I started at around 200 feet, was inverted at 175 feet and then started losing maybe 10 feet per second down to 100 feet, where I peeled out. I’ll keep at it though.

- As Yoda always said, “Control! You must learn control!” Improving my stick control is improving my flying. Of course, I still crashed 3 times… But that’s ok, I just brushed away the grass and mud, plugged the battery back in and zooOOM!

As for control surfaces… It always seemed to me that the horns were placed too close to the center of the plane. If they were moved out to the middle of the wing, the far end of the elevon wouldn’t have nearly as much of a chance to flutter or strain. Net result: more responsive flight. That’s my thought anyway. I haven’t seen any photos of such a configuration though. Thoughts?

- I learned a valuable lesson about near-stall speed flying and elevon airplanes. It had to happen to me twice before I sat the plane down in the grass, put my fluid dynamics hat on, played with the controls and thought about it for a while. The lesson is this: If you’re flying very slowly and pull a hard turn… lets call it a hard right turn, the right wing now has it’s elevon pointed up in the air like a flag. At stall speed, that wing isn’t going to bank and turn the plane. Instead the elevon will act as an AIR-BRAKE, slowing that wing down and sending the plane into a really cool though horribly tragic spin. What does the airplane doctor say about that? “Don’t do that!” “But Doctor, sometimes I find myself in that predicament when flying fairly low and then making a turning error.. Like for example turning away from the wind too quickly.” The doctor just repeats, “Don’t do that.” And I bow my head and agree.

- Could someone else put their stock zagi on a postal scale and crank it up to test how much thrust their motor is generating at full throttle? As I said before, mine comes in at 12 oz and the Zagi site shows 16 oz. Which is more normal? Of course, this number isn’t a totally accurate representation for flying because the prop might be stalling when there is no airspeed (in the test environment) but in the wild, when the plane is flying at 25 mph, the prop wouldn’t be stalling.

Cliff writes
>>How are you charging your battery? it should be at 2 amps max
>I’ve been charging at 2C to 2.5C, 3.4-4.25 amps. I’ve done that about 12 time

Hmm, I just reread the Zagi manual…. ”
SANYO RECOMMENDS CHARGING THE KR 1700AE CELL AT A RATE UP TO 1
AMP….SOME MODELERS REGULARLY CHARGE THEM FOR 40 MINUTES AT 2 AMPS.

Oop. My bad! But I so often hear about charging nicads at 2-3C…. ugh. I suppose slow charge time is part of the penalty for these batteries having such a good weight to energy density ratio. I’ll be good to my batteries from now on.
- The heavy aired misty day worked to my benefit. The wind was light and there was no one else there. If there’s glow planes on the field, it’s a bad idea to just walk into the middle of the field for the fun of having the plane fly by 5 feet away!

—————————–

Now I’m coming around to the Zagi way… I’ll probably be getting another battery pack and a brushless motor soon. Cliff has been good to me from the beginning so I’ll likely get it from him. :-)


226 hits in 76 visits from July 17, 2003 to Aug 31, 2003.

Kenvil Hobbies Visit, WCCC Flying Field

March 7th, 2003 12:00pm. RC

I went to Kenvil Hobbies the other day. I ended up hanging out there for an hour or so, talking about electric planes to the proprietor and a couple customers. It was nice. I ended up buying an 1100 mah Ni-MH 9.6v battery. I initially thought that I had bought it out of a need to buy “something, anything” from the nice guy at the shop (we spoke for a good long while about the potential badness of not having a local hobby dealer), but after I flew with it once, I was very pleasantly surprised at the zippy, light-on-it’s wings performance I got when I flew with this very light battery. I know that I wouldn’t have bought it otherwise… I probably would have bought another (heavy) Zagi 1700mah battery.

I found a great new flying field, the front yard of my community college, WCCC. So now I can fly before and after class. :-)

In that photo to the right, the school is in the lower right portion and the field is centered. It’s like 220 yards by 100 yards, plenty big enough for my “fast park flyer”. Just across the way in the lower left corner of the map is the Warren County Technical school. They’ve got a couple signs that say, “No ball playing, no running,… blah blah, no R/C vehicles…” And just to the south of the map is the Warren County Communications center, complete with big multi-frequency radio antenna. I hope none of these folks get mad at me for flying… But then I don’t dare ask, because they’ll of course say, “No, and we’re going to keep an eye on you now, you suspicious terrorist-type.”

My favorite is that with the 1100 mah battery, I can fly along, pull back on the stick and the plane lifts it’s nose like it’s been startled awake from a daze. And up she goes!

Skywalker: “What a piece of junk!”
Solo: “She’ll make point five past lightspeed. She may not look like much but she’s got it where it counts, kid. I’ve made a lot of special modifications myself.”

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