...in addition to flying yourself. I have a new toy, for the days when it's not nice (enough) to fly myself. But like all the toys that I like, it requires loads of tinkering and a little bit of skill. It's a radio-controlled glider.

Here's the progress report so far. A few weeks ago, I spent a blown-out afternoon at Beechmont playing with Aaron's wing, and finally decided that after 20 years of no RC flying I've got to get back into it.

Being the perfectionist I am, I spent some time reading reviews, checking sources and (always money-wise) looking for the best price. So the Windrider Bee got ordered mid-February. It's an all-EPP foam plane, molded (not hotwire-cut), without spar, very solid and apparently well-liked for its speed and agility (some reviews here and here) -- and it's dirt cheap: $109 was Vagg's price, plus $15 postage. The package comes with everything and then some: all the strapping and covering tape, servo horns and pushrods, two big stickers and three whistles (which I didn't install). The only thing that sucks is the instructions, but then it's really easy to figure most things out anyway.

 2007_02_20-bee-box-contents.jpg  2007_02_20-bee-box-extras.jpg  2007_02_20-bee-box.jpg

The glider can be built without any glue, but I decided to glue the halves nevertheless. Contact glue (aka Pattex, cheapest source here: KS Bond) is perfect for EPP foam I've learned.

 2007_02_20-wing-gluing.jpg  2007_02_21-wing-glued.jpg

I decided on having an external switch on the top ("on" is forward), and that the antenna must go in a nicely cut slot under the cover. The pack actually comes with nice coreflute doors for the RC gear, and all of it is held together and made solid by strapping tape.

 2007_02_22-antenna-installation.jpg  2007_02_22-rc-gear-and-doors.jpg

After some trickery with the ailerons (hinge: 3 strapping tape strips each side, then clear packing tape on the top),

 2007_02_23-hinges.jpg 2007_02_23-bottom-hinges.jpg 2007_02_23-bottom-strapped-ailerons.jpg

the whole shebang was covered in colored packing tape. The receiver cover was hinged with strapping tape, to gain access to the battery charger plug. The rest of the RC gear is (semi)permanently installed: you need to go through the strapping tape but then you get little loops to pull things out easily. I do think ahead :-)

 2007_02_23-front-strapped.jpg 2007_02_23-covering-starts.jpg  2007_02_23-covering-bottom.jpg 2007_02_24-bottom-covered.jpg  2007_02_24-covering-top.jpg 2007_02_24-top-covered.jpg  2007_02_24-top-decorated.jpg  2007_02_24-bottom-decorated.jpg

This was the state very late last Friday. Come Saturday morning, I crawled out of bed and tried to charge my transmitter battery with the Swallow. And blew it.

The transmitter is a not-too-expensive used JR XF631, a six-channel computerised model, which I got complete with all nicads, 4 servos, receiver and crystals for just under $200 off ebay. Nice gear, but the JR engineers should roast in hell for a) using a normal charging plug for the transmitter but with reversed polarity and b) incorporating some stupid trickle charge program into the transmitter.

In the morning I thought that I had maybe reversed the reversed polarity, and frantically started ripping the transmitter apart: would be real cool to blow $200 out of the window before even flying a single time! Fortunately, it was only a blown fuse. Replacements got procured in the arvo (a number of them!), and in the evening I tried again (post-coffee, hence with brain active). There goes the second fuse! See, the JR gear comes with a dinky wallwart and doesn't survive anything else. The charging circuit in the transmitter sucks pretty badly and even the battery check/cell detection of an intelligent charger blows the fuse.

So no in-place charging. Fine, but the transmitter nicad was pretty much shot (holds only about 280mAh, rated 600mAh). So I embarked on a sparky journey to the lands of Jaycar, home of stacks of cool gear and other wallet-reducers. $48 later, I have 8 nimh cells, rated for 2400mAh 8-) Soldering these into the required form was tricky, I shorted 4 of them for about 1.5 seconds, during which the metal tabs actually started burning...

And then the shrinkwrap was of the wrong dimension (too large). Net effect: crap. Now no more shrinkwrap, and hello electrician's tape!

 2007_02_24-fuck-heatshrink.jpg 2007_02_24-xmitter-battpack.jpg

But Sunday was good: first maiden flights of the Bee, all went fine (but it needs some ballast in the nose), and some flying for me myself as well. It's really very nice to fly something when you don't want to fly yourself.

Now the tinkering started. I wanted a lost-model alarm, so that retrieving the Bee from the bushes gets easier. Buying one? nah. Building your own? hell yes! This introduced a whole new universe to me (and my wallet), that of PIC microcontrollers.

But, for now mostly following this project, I made this tiny alarm. The chip, a PIC12F509 was socketed so that I can reprogram and extend its capabilies (maybe replace it with a 12F635, with which I could also make a low-voltage alarm). On the pictures at the bottom you can see the alarm on the side of the switch. Yes, it's that small but makes quite some noise...


And today I solved the ballast setup. The further forward, the more lever and less ballast needed. On the other hand, the very leading edge is prone to impact damage if I carved out too much foam there. And what ballast? that was easy, go to the nearest fishing shop and buy a bag of cheap lead sinkers for $3.98. Yesterday night (or rather today, at about 0300) I had the inspiration that flattening the sinker balls might be good for mounting, but I couldn't hammer at that time. This afternoon after work I tested that flat earth theory with, well, mixed results. In the end I went for this scheme: two paper strips bent into clover shapes to hold up to four lead balls each, which get sunk into the not-quite leading edge, as far forward as sensible (keeping clear of the battery and the servo bays). Load ballast bays, cover with strapping tape (or packing tape or electricians tape; the clovers hold the balls quite tightly). No movement, no loose stuff on impact but still utmost convenience for readjustment.

 2007_03_01-weight-sets.jpg  2007_03_01-weight-installation.jpg  2007_03_01-weight-installation2.jpg 2007_03_01-weight-installation3.jpg

Worked great. Perfectionist that I am, the clovers had to be glued in. For safety, you know :-) We'll see what kind of flying the next three days bring...

[ published on Thu 01.03.2007 23:51 | filed in interests/flying | ]
Debian Silver Server
© Alexander Zangerl