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Archive for March, 2012
Posted by mandevil | Mar 25, 2012 @ 04:41 PM | 3,267 Views
Last weekend I cracked Bixler's tail. So during week I glued the crack and applied hot water. There still remains some bend, but it's fairly minor I don't think it has any bearing on actual flight. Also, I glued 3 mm carbon rod into the groove in the bottom of the fuselage with epoxy resin. Never worked with epoxy before, but it seems to hold fine.

OK, repaired plane goes to the nearby slope on Saturday. There's quite fresh wind and I go on slope soaring for the next three hours. I mostly try to just soar, with only occasional bail-out with motor. I try to get the hang of slope soaring, I try quick turns along the slope edge (no, that doesn't seem to go very well with Bix, I don't seem to be able to do them fast enough and I lose lot of altitude, I try to do gentle circles (seems to limit altitude loss, but wind is often too turbulent and changable to do this well), I try to keep plane afloat at all cost, as if I don't have motor (which inevitably leads to crashes when I try to turns when too low or too late). At any rate it's fun and learning experience. I only use about 600 mAh of battery, I'd say about 80% of the flight time is completely unpowered. I probably could use little stronger wind with more intense lift. Bixler is no fast glider so you really cannot gain too much kinetic energy from the wind, which limits its slope abilities.

My girlfriend was kind enough to shoot some nice in-flight pictures. See more pictures in gallery.

When I was almost ready to...Continue Reading
Posted by mandevil | Mar 18, 2012 @ 04:34 PM | 3,247 Views
On Saturday I did some video flying under castle ruin Blansko and took about 25 minutes of footage, but unfortunately, it doesn't appear to be any good. I have no idea why, but the flight is very jerky. It's as if the plane is constantly being upset by something. With my previous plane (which had the exact same airframe) the flying seemed smoother (though still far from ideal).

On Sunday I took Bixler to a slope. I didn't expect slope soaring, but actually the wind was fairly favourable and I managed to keep the plane in air for a while. After some time I noticed that both my ailerons are little up -- both the same amount. This looked strange and I suspected something wrong with servos. I readjusted the clevis/pushrod linkage, but after more flying the ailerons were up again, this time little too much for comfort. I thought the session's over and started packing, but then an idea flashed in my head. I turned the right knob on my TX and indeed, both ailerons raised and lowered as the knob was turned. I completely forgot that I still have active setting, that allows to adjust the ailerons symetrically when the right switch is on (that is either as spoilerons or flaperons). Oh well, I readjusted the aileron linkages again and continued flying. Unfortunately the wind was quite changeable and I suffered few light crashes. It all ended up when I discovered that my tail is crooked from a crack in the rear of the fuselage.

Note the raised ailerons. This was the moment when I decided that something is seriously wrong and decided to stop flying.

This is how I ended the day; the crack in fuselage is barely visible right below the horizontal stabilizer on the right side. Inevitable when you fly too carelessly.
Posted by mandevil | Mar 13, 2012 @ 05:59 AM | 3,379 Views
On Saturday I did some powered flying, mostly training catching the plane on landing (with not that much success). I discovered quite strong tendency of the plane to turn to left with high throttle. Nothing unmanageable, but fairly noticeable. The wings have tendency to unlock on harder landings and also catching the plane by wing is not good thing to do, but the wings seem to hold well during flight.

On Sunday the wind seemed to be quite strong, so we went to a nearby slope. Even if the wind direction wasn't optimal, there was lot of lift there and it was fun soaring for about 20 minutes. Then the wind picked up enough that I started to have problems staying on the upwind side and also worried about the integrity of the plane as I saw it being buffeted by strong gusts. Fortunately I managed a perfect landing by snatching the plane from air in mid-flight. Quite a stress test, but a successful one.
Posted by mandevil | Mar 04, 2012 @ 01:49 PM | 3,538 Views
Today we went to a slope and tried some soaring. There was some lift, but not enough to sustain flight, though paragliders were soaring nicely nearby. Maybe the spot I was on wasn't very good. I also crashed a little, but nothing got broken. Then we moved to another location and after quick test I put on my GoPro HD Hero and spent rest of the time flying with the camera attached. I made some 45 minutes of footage (on two batteries). Flying was OK, nothing unexpected happened (apart from my accidental switching off throttle and gliding to unexpected landing), wings were holding just fine, even ESC wasn't sliding off its velcro strip. Great.

Unfortunately, the footage is quite disappointing. The flight is very unsteady and I don't have good idea why it is. I reviewed my previous raw videos and they are definitely steadier. My hope is that the wind was rather gusty and that flying in better conditions will yield better video, but I'm bit dubious about it. Well, I have to wait and see.

I'll post the video when it's ready (that's gonna be at least several day, just first pass of Deshaker is about 6 hours).

BTW, I used up 4150 mAh (in three batteries).
Posted by mandevil | Mar 03, 2012 @ 03:47 PM | 3,361 Views
So finally, weekend is here, so I get ready my new Bixler (after gluing back aileron control horn that came loose after I hand-forced servo... aehm). It's been sunny, but windy and chilly. I made number of launches, testing various modes of flight. Relatively strong wind made it impossible to do any fine-tuning. I tried some aerobatics (loops, inverted flight). My main concern was if the wings are held together sufficiently well. Well, on about two occasions, the wings became partially unlocked, though not completely loose. At home I discovered, that one of the magnets is unglued. So I glued it back and we'll see. Maybe I will need to add more magnets, maybe I need to try something better.

Another little thing is that I use stick-on velcro to hold ESC in place. Unfortunately, the glue starts to flow when ESC gets warm/hot and the ESC gradually slides off the velcro. I used some CA glue and we'll see what happens.

As for the motor performance (Turnigy 2826 2200 KV): I haven't flown my previous plane for half a year so I cannot do a good comparison, but I would expect a little more from motor that has some 140 W of rated performance more. It's hard to evaluate the climb rate with ever present wind, but it doesn't seem to be that radically better. Sure, it's got a lot of power, but it's still not vertical climb. We'll see when I get some calmer day.