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I replaced one battery in my transmitter battery pack. For as long as I’ve had it, the transmitter was only good for just barely 1 1/2 hrs of flying time per charge. I finally tested it and found that one cell was completely shorted out, 0 volts. I think that it’s always been like this but I never looked into it. The new battery is a Radio Shack 700mah AA cell. The other batteries are 600mah cells. I hope it works alright.

I fixed the motor mount and flew on Saturday :-)I created an EPP foam motor mount. You can’t see in the image but where the front of the motor touches the foam (in the photo, very close to where the blue wire is soldered to the motor) I buried a quarter in the foam to distribute the force of the motor sliding forward during a sudden stop.

I found a coroplast sign on the street that no one was using [grin]… (one of those awful “Lose 50 lbs in 10 days, Guaranteed!!!” signs). I cut a long rectangle of it and put it on the bottom of the plane as a reinforcing plate. I then sliced holes down through the wing to insert “GB Grip Strip” velcro strapping from Home Depot. This strapping now holds the motor in place! As well, I put strapping in front because, cool as it looks, I want to stop the battery from it’s habit of flying loose and cutting into the ground like a throwing dagger tossed high in the air during my inverted stints.

A couple times now, the battery has come loose! Just this weekend it happened too… before we put the battery strapping on. Julian and I had finished putting the motor mount on, and I wanted to FLY immediately. So I gave it a toss. I was showing off my new inverted skills over the strip when…. the engine cut out suddenly, the battery flipped 200 feet with a thud (Julian was looking away at the time but he tells me that he felt the thud!) and the plane wafted down like a giant sheet of construction paper let go from a building-top. Yea, time for better velcro on the battery!

Die Hard Fliers

I am now officially a die-hard. It drizzled on us a couple times when we were out flying. We kept watching the sky, wondering when we’d get the brunt of it. I went up and was having a blast when… It felt almost like I was getting tunnel vision. I was losing my peripheral vision due to a sinister darkness that was sneaking up on me from behind! The air suddenly smelled different. The leaves on the trees flipped over. It was time! The rain hadn’t started but I called out, “That’s it! Here comes the rain!” As I was landing and packing up, the rain started…. and then in earnest! It poured! Four of us hid in the RAMAC shack. Julian luckily had the combination to the lock, there was also a Russian man named Gen and …. oh dear, I forget the last guy’s name. We sat around talking about Gen’s diesel powered control line plane. He last flied a control line when he was 15… an old diesel :-). His new plane had a new engine on it… but it was the exact same model engine :-). Diesel engines are more efficient but they can be a REAL pain to start. While it rained, he worked on getting it started for an hour or so. The smell of the fuel was wild! It’s 1/3 ether, 1/3 kerosene, 1/3 mineral oil. The ether gives it this cool, fruity, clean smell… maybe like a doctor’s office… After a few minutes in the shack with him starting the engine, (the door and windows were open, but still…) we were all permeated with the smell. I didn’t mind.

The rain finally stopped after 1 1/2 hrs or so. We went out and Gen really wanted to get his control line flying. I wanted to see it. I only have 1 vague memory of ever seeing CL and my dad talks a lot about how he flew CL when he was a kid. He finally got it started, I held it, he gave the signal and I let it fly! It went up. And it went down. Smoosh. 5 seconds in the air. The damage wasn’t too too bad… the wing was crushed from the “Art” decal outward. :-(.

After we all moped about the smooshed plane, I whipped out the Zagi to cheer everyone up. I have Gen the controls… he asked if we were ready for a low flyby; he almost hit the shack! It was a gas! I landed on my own once in the parking lot (RE: the mud on the plane in the pix) and Julian caught it once.

On the way out, Julian’s brother finally showed up (only like 3 hrs late) with Angelina, a friend. We had a very nice time talking there.

Stunt flying at night with no lights is dumb.                   And it wasn’t even that fun :-(I have an idea as to how I can fix the motor mount with EPP foam instead of that flimsy, brittle plastic.

I’m reminded of Cliff Whitney’s email .sig. “When flying upside-down, down is up and up is expensive.” Well in my case, up just got me to improve my super-gluing skills. I was working on my rolls and tried doing fun stuff in the roll. I found that the following combination puts the plane into this wacky roll where (if done right) you barely lose any altitude and the plane looks…   I don’t know… cool…:- Dive, then pull up to gain a little speed and an upward angle
– Hard turn right
– When the wing passes vertical, push the stick far-right and far-forward
– When the wing passes vertical again, push the stick far-right and far-back
– Flatten out and smile.

The plane doesn’t roll nearly as fast as just a hard turn. While it’s inverted, it gains a little altitude and it looks like the right wing (which is now on the left side) is being pulled up while the left wing is just sitting there. It looks pretty cool.

I was also working on getting really comfortable with inverted flight. I’m almost there! The Zagi keeps trying to right itself (which is a good safety release) so you have to fight it while upside-down and turning. I was trying to recover from a botched krazy roll; I tried to pull out inverted and…. well… I got my controls confused and drove straight into the ground at full throttle. The motor mount was smashed. I repaired it with superglue and that superglue quick-drying stuff.

Also, it was pretty cool when I dislodged my battery at about 100 feet. That happens when you’re inverted and wiggling a lot. Duh. The battery flew out like a throwing knife and stuck in the ground about 3″ deep. Cool. Happily, the controls were locked in a position where the plane wafted down like a piece of paper… back and forth… back and forth. Ploop.

Wow, I burned through 5 batteries today.

I’m going to keep track of my battery usage until both 1100mah batteries have the same age on them…. So here is a new section of my journal. Tracking. woop.

• Battery 1: my original 1100mah ni-mh. Has approx 19 flights on it. Charged at 2.5C approx 4 times. Charged at 1.5C approx 10 times. Charged at 1C or below approx 5 times.
• Battery 2: purchased 6-22-03. Same as Battery 1
• Battery 3: Zagi KR-1700AU. Has approx 21 flights on it. Never charged above 3C. Charged at 3C without air cooling maybe 4 times.

I wussed out and bought another battery pack from Kenvil Hobbies instead of building my own out of snazzy 1700mah Sanyo HR-4/5AUP Ni-MH batteries. I just didn’t feel comfortable spending $80 in batteries ($4.50 apiece + shipping), another $30 for battery bars, shrink wrap, wire, soldering gun, & connectors… and THEN have to put ’em together in my lair. All that work would get me packs that are only marginally better than what I could get from Kenvil Hobbies for $35 apiece… for something like $55 apiece.

So I was picking up misc. items at Kenvil Hobbies and I just bought a battery pack. It’s the same type I got last time. So I’m going to use the new battery 19 times (occasionally abusing the charging times… just like I did on the first battery) and then I’ll start charging them in series together. That’ll be nice… more air time, less charging time.

I flew today. I’m enjoying inverted flight.

When I bought the new 1100 mah battery, I told myself that I should return the 100 watt Radio Shack soldering gun (64-2193) I bought to assemble packs with. But I didn’t :-).

I had never used a gun before. All these years I had this impression that irons were the way to go… because. I’ve got the Radio Shack 15/30 watt dual heat iron and have been happy with it for a long time. But after trying the gun, I’ve got to say that I am -very- impressed with it’s power and ease of use. IE: Plug gun in. Pull trigger for 10 seconds. Start tinning tip of gun. [yes, 10 seconds, not 10 minutes] Release trigger while positioning pieces to be soldered. Pull trigger and wait 3 seconds. [yea, it’s a slight bother that it’s not always at the ready like an iron, but the tip needs less tinning] Touch tip to Deans Ultra connector, wire and solder for 3 seconds to solder together. [The 30 watt iron would take 10-20 seconds of heating time]. It’s also nice that the gun is safely cool again in 5 minutes.

I like the gun.

So now that I’ve spent the $12.99 on the gun and I’ve browsed too many battery websites, I might just build my own packs after all. More details as they develop.

As I was going to the field, I heard a severe weather advisory for eastern PA…. 30 miles to the west of me. Did that stop me? Nope! Of course, I flew like crap in the gusty 25 mph winds…. but I flew! I also busted the elevon again when I hit an outfield foul-line pole. Nothing a little Krazy Glue can’t fix. I can now get into inverted flight via a 1/2 roll… in 25 mph multi-directional gusts, no less. Tré cool.

Optimally, I’d want a battery 1500mAh battery, under 10 mOhm, under 30g. 20mOhm is right out. Here’s stats from Sanyo’s website

comparison according to Sanyo charts:
CP-1300SCR – drained after 8C for 6.9 minutes. that’s 10.4 amps for 6.9 min (.115 hrs). 10.4 * .115 = 1.196 amp/hrs
KR-1700AU – drained 8C for 5.2 minutes. that’s 13.6 amps for 5.2 min (.087 hrs). 13.6 * .087 = 1.1832 amp/hrs
Conclusion: you get an insignificant 1% more amp/hrs out of the CP-1300SCR during high drain applications (like flying wide open throttle). At lower drain, like when cruising around, the KR-1700AU does better.

The HR-4/5AUP looks like the best candidate. Andrew Mileski on the Zagi group says it’s his favorite and that’s good for something. It pains me slightly to spend $70 in batteries + $20 pack making supplies… Hmm. But thinking about it, I’ll then have 2 complete kick-ass packs for $45 apiece. So the cycle would be: fly the 2 new packs for 25 min. Fly the 1100 Ni-MH for 10 min while letting the pair cool. Start charging the new pair at 1.5C. Fly the 1700 Ni-Cad pack for 15 min. Sit out for 30 min. Then start charging the 1100 Ni-MH and start flying the pair for 25 min.

I suppose the best and most simple configuration would be for me to have 2 pairs of batteries and a charger with a charge delay. Then it would be:
fly pair #1 for 25 min
plug pair #1 in (with a 5 minute cooling delay on the charger) at 1.5C and fly pair #2 for 25 min
sit out for 20 min
plug pair #2 in at 1.5C and fly pair #2 for 25 min

But now I’m just fantasizing…