Lee.org

Julian and I went to Stick 40 Combat in the Poconos. A very nice day! I flew in front of a large audience for the first time. I got over my nerves quick enough… but then I had time for 5 or 6 flights. Near the end, I crashed kinda hard in the corn field. I went out, brushed it off and gave it a toss. I heard an astonished comment behind me and smiled.On Sunday, I had crashed pulling out of my first good inverted flight.. Yesterday I was able to do some inverted flight without a dramatic ending. Here, let me get more technical about my recent improvements:

• The Sullivan Gold-n-Cable #507 .032″ cable that I used for the cable system is a little too thin. I finally got it to work well, but it was a pain. The look is nice but… eh.
• My purpose for the cables was to improve handling by moving the control horn to the middle of the elevon. Unhappily, the plane does NOT fly any better with cables. It’s still flittery in high wind and smooth in low/no wind.
• The smoother covering job helps a little with speed… just a little. Or maybe that’s me thinking that a pretty plane flies faster.
• The balsa elevons have broken 4 times in 3 places. I’ve repaired them with CA but I’d like to get 2mm coroplast.
• I think the motor has a little more thrust now… it’s broken in. I had previously measured a static thrust of 12 oz. I’ll try that test again soon.
• My batteries are breaking in well. Today I did C/5 charges after draining them and put 1800 mah into the 1700 mah battery and 1300 mah into the 1100 mah battery. However, the 1100 mah battery was very warm when it peaked… there might be a growing cell instability issue there. I’ll keep an eye on it.
• My piloting skills are improving dramatically! I don’t -feel- any different but somehow I can now easily do 2 or 3 rolls at a time when just a few months ago I could barely do 1 roll. I can do multiple inside loops with ease, zoop all around comfortably, and am confident with many low altitude maneuvers. Just ask Julian about that last one. I buzzed him when he was trying to take a photo. I came so close that he dropped to the ground! Hehe! Not to worry… I pulled out in time, and a collision with a foam wing is pretty benign. (as long as it’s not the space shuttle you’re hitting :-( )

Photos from last weekend:

Julian and his plane are to the right. Notice the tractor in the background. Which do you think would win in a collision, the plane or tractor? Julian and I know! (he hit the tractor’s wheel with his wing on an approach to a dirt landing strip. The plane sustained relatively minor damage. If the plane had been 2 feet to the right, it would have been scrap)

I don’t remember if I’ve said this in the journal but Julian is a terrific pilot!

Sorry I don’t have any good action shots of either plane. It’s hard taking shots of a little plane zipping around, especially when my camera doesn’t actually take the picture for 1/2 a second after you push the button!

Went flying with Julian again. It turns out that I had not accomplished the impossible :-(. Julian pointed out that channel 2 was backwards. With the flip of a switch, the impossible was possible again. :-)   )-:Zagi is in the air again! More updates and pictures soon.

That’s not to say I accomplished a -good- impossible thing… but my accomplishment is nevertheless impossible. But let me start at the beginning of this very eventful week.

I took my dad to Lakehurst on Independence Day. His father had worked there more than 50 years ago! We watched the indoor flyers for a few hours. We even got to see a record be broken. A man had driven down from Canada for the “good air” in Hanger 1. He was flying a large class plane (I don’t know the exact name) and broke the Canadian record for duration. I watched it take off and then land 34 minutes and 10 seconds later… All on rubber power! They took 5 seconds off the time because he had to use a balloon to steer it once, but 34:05 sets the Canadian duration record by about a minute! Cool.

We also went outside with Robert Romash to slope soar his Zagi Combat wing against the wall of the hanger. He let me have my first hand at soaring. Tré cool. It’s a much different experience than motorized flight. Before going outside, Rob showed off in his inimitable manner by flying the wing indoors… It’s like a high-tech boomerang! He’d give it a fierce throw and he’d bring it back with panache.

I met Julian (a new flying friend :-) at the RAMAC field on Sunday. Since my wing wasn’t completed yet, he let me fly his planes… an ugly stick 40 and a seagull. He tells me that he built the seagull in just a few days with no plans… just by eye. Very impressive.

We flew for a couple hours. A guy with two 70cc gasoline powered fighters came by, a guy with a helicopter, a guy with a trainer… unfortunately, the guy with the trainer left with more plane parts than he arrived with.

We tried out my new Zing Wings. They’re these cute little rubber band launched gliders. They actually are quite a bit of fun. They only go up like 50 feet but they spiral around in nice big circles, cruising around.. neat. The plan was to give them to visitors and kids to fly while I’m flying my plane. Yea, I’ll do that. Of course we had to attach one to his Ugly Stick. The best placement was by putting the Zing Wing with one wing above and one wing below the Ugly Stick’s wing. Then a bit of throttle held the Zing Wing in place. He got it up to 300 feet or so and did a hammerhead to release it. It was HIGH! I ran after it but the wind carried it pretty far pretty fast. I lost track of it a couple times and ended up just standing there scanning the beautiful partly cloudy sky for a sign of that glider. No luck. It was gone! I like to think that it went to airplane heaven. Now it’s out there playing with all the other lost airplanes… like the big camouflage colored fighter-plane that some guy lost a few weeks back. It was worth it watching it just soar away.

Julian tried a few slick landings after that. Since the field is on a sod farm, there are strips where the sod has been pulled up and sold. Those strips made nice smooth runways on this day. He tried landing on a strip just across the canal and into the wind. Nice. Though with no brakes the thing rolled for a really long time. Then he wanted to try a crosswind landing. That strip started 5 feet in front of and downwind of where we were standing and continued a good 100 yards to our left. It was bound by the grass we were standing on to our side and a sod tractor on the other, about 30 feet downwind. A tight fit but he’s that good. He brought the plane in on a pretty nice crosswind approach. He had good rudder action to compensate. Both our heads were turned toward the plane which was going to cross from right to left onto the runway. It flew by on approach. Both our heads turned to follow and then we saw it. The plane was too far downwCRASH! into the tractor. The right wing hit the big rubber wheel, it spun around like a top, banged the tractor once more for good luck and hit the ground tail first.

The damage was weird. The end of the wing got a good scuff but was ok. The fin of the tail broke out of it’s slot (happily an easy repair). Strangely, a 1/2″ x 1/2″ x 1/8″ piece of structural balsa that had been inside the plane was knocked out and then embedded somehow in the skin of the wing! It wasn’t just sticking out, it flew out and then flew back in again! Weird.

But that’s ok! That’s why you bring two planes to the field! They’re like classic Jaguar automobiles. You buy one for the road and one for the shop. He let me take control of the seagull for several short flights (air was getting in the fuel line or something). I made a couple textbook Immelmans, some very nice rolls (the wings have practically no camber) and had just a blast. I was doing these tight sideways inside loops around and around and around… weeee! When I tried to pull out of the loop, badness ensued. Apparently, even though I was still whizzing around as fast as can be (the plane has no throttle control. It’s full-speed ahead until you run out of gas!) I had gotten down near stall speed and the wings started performing poorly. I spiraled right into a ditch! No, not a ditch, a small canal!! When we reached the plane a few minutes later, it was 3/4 submerged. We drained it and brought it back right away. We were both really afraid that the 6 channel PCM receiver (read: expensive) was dead. Happily it was ok but we couldn’t get the motor started.

That ended our -long- day at the field. We went back to my house and worked on the Zagi. Julian helped me finish reconstruction. Click on the photo to the right for a good shot of Zagi 2.0. Sullivan #507 .032 Gold-N-Rod cabled elevons, a better Oracover job, a better cut tray and top… kickin’.

Unfortunately, I realized that the cables weren’t supported well enough at the ends. See the zoomed in photo of the cable… See how the wire is a little bent? Well, when I gave full down elevon, the wire would bend. Suckiness. I used some hot glue to create a strut beneath the unsupported cables. Inside, the wire was bending at the servo too. I bent two paperclips into croquet wicket-like things and glued them in place to hold the wire near the servos down. Done!

Well, not really. You see, that’s when I realized that I had performed the impossible. The controls are impossibly messed up. I threw it a couple times and the plane spiral wildly out of control. Even when I’d pull a hard right turn on launch, it rolled hard left. I checked the controls… up, down, left, right, elevon mixing. Everything was good. Scratching my head, I threw a couple test flights.

Launch --> pull back on stick    --> plane goes up

Launch --> push forward on stick --> plane noses in

Launch --> pull stick right      --> plane rolls left

Launch --> pull stick left       --> plane rolls right

This, as everyone patently knows, is IMPOSSIBLE! If up and down work correctly, and elevon mixing is set correctly (it is), then left and right HAVE to work correctly. I’ve only got two control surfaces! It’s like… you’re standing on a street corner in New York City. The Walk light comes on. You look left, you look right, and as you step off the curb, a car falls from the sky onto your head. It just doesn’t happen!

Hurumph! I’ve thrown the plane about as many times as I dare and it behaves quite predictably in the way I’ve described. I tried throwing it slow. I tried throwing it fast (ouch, I broke my new canopy), I tried to adapt and fly the plane with these wacked controls. No.

I’m gonna call Julian up and have him stare at it for a while.

OUCH! From YourZagi.com and http://www.wrightbrothersrc.com

You know, the more I stare at speed 400 brushless motors, the less I think I want one. It basically comes down to:brushed vs. brushless speed 400 motor

• Brushless is 20% more efficient (making for potentially 20% longer flights)
• Brushless is $200 ($100 motor, $100 ESC), brushed is $40 ($10 motor, $30 ESC)
• Brushless provides 2x the thrust per lb of motor (drawing about 1.6x the amperage…) (average 400 brushed motor is about 3 oz) giving me the opportunity to push the throttle such that I’ll use up the battery really darn quick.
• top level flight speed goes from about 50 mph to about 70 mph
• Brushless improves powered handling considerably

I’m not into electrics for super vertical performance. I’d switch to .90cc glow engines for that. So I’ve been looking around and I’ve got a lot of other options besides plunking down $200…   I could switch to a high performance speed 480 motor, an 8″ x 4.5″ prop and get 3/4 of the way toward a brushless for under $20. Hobby Lobby reference. Or a Rocket 400… or the new Zagi Speed 400 for $10. I’ve got a lot of options that cost a heck of a lot less than $200. Hey, $200 would get me a lot of Estes model rocket engines….

I’ve started ripping the old covering off the plane.

My mom isn’t the best pilot. How do I know this? This is how I know:

Don’t let it be said that the Zagi flying wing is indestructible. I brought my mom, dad and niece out to the airfield yesterday. After a couple minutes of flight (they oo-ed and ahh-ed in all the right places), my mom wanted to try her hand at it. So I gave her a quick lesson, brought the plane up to 200 feet (what I thought to be “2 mistakes high”) and handed her the controls. She promptly pointed the nose down and gave it full throttle. Three seconds later, there was a 5″ deep hole in the ground. It was astounding. RIP Lee’s Zagi version 1.0

Dad and I have been having a good time joking about it. We’re saying that we should get her a purple heart. Or maybe she should have watched more of my dad’s war TV shows before taking to the air. She just keeps repeating how she’s so sorry and will never fly it again.. never ever ever. But I struck a deal with her. I’ll feel better about it if she learns how to fly and takes the controls just one more time. After all, we can’t have her grieving about some silly little plane forever. It also doesn’t hurt that she volunteered to pay for the damage. That last bit means I’ll be rebuilding the plane to version 1.1 :-). I was never happy with my Monocote job. So I’ll send away for new trays, maybe a new motor (brushless?? hmm? hmm?) and we’ll be back in the air in a month or two. Actually, speaking of indestructibility….. The only things I lost in the crash were the motor tray and canopy. The entire rest of the plane is still intact! wing, winglets, elevons… The motor, receiver, and servos are still good too. It’s the loss of the motor tray that “killed” the plane. That’s because I have to rip out a lot to fix it the motor tray. And if I’m going to rip out so much, then I want to do a total overhaul.

The Cosel K150A 12 volt, 13 amp power supply came in the mail today. I hooked up wires, plugged it in and it worked right out of the box. :-) I’m very happy to be rid of my Rube Goldberg battery charging contraption. It used to go:Car battery charger set on 2 amp manual charge
–> block of UPS batteries
–> Astro charger
–> nicads

The UPS batteries were there as a power sink/capacitor because they say that a car charger doesn’t have an even enough output to be trusted going straight into an electronics device (I believe them)

I’d have to watch the state of charge on the UPS batteries or badness would ensue. And when done, unplug the whole thing. To boot, the lead-acids were on their way out. I charged them individually last night and today 2 are at 6.39 volts, 2 at 6.29 volts. Maybe I’ll keep 2 of the lead-acids as field-chargers.

But now, when I’m home, I can “Set it, and forget it!”

————————

I -was- going to wish for An Astro 020 brushless motor with controller from Atlanta Hobby for Christmas but after looking into motor and prop efficiencies (see my Flying Tips page) I’m not exactly sure which motor I want. I’ll have to research it some more.

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.

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.

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.