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Archive for October, 2015

# waves (or fronts?)

Posted by phil alvirez | Oct 15, 2015 @ 03:31 PM | 9,464 Views
waves are spaces where lift is found. their shape is similar to a sea wave. i have been flying in waves long enough to understand their behaviour at this field. it is in a flat area all over, some 5 km north of lake erie, and the prevailing wind blows from the lake too.
and the great thing is that i have the vario that sends tones and switching i can get height too, so it is as if they were colored clouds. no guess work. with this i have been able to learn:
1.-they are found on a line across the wind;
2.-climbing to 200 meters is where i find them;
3.-at this height they don't move. are stationary for a long time;
4.-if i climb to 300 meters i find thermals that drift with the wind:
5.-this happens even in clear sky, but not all the time;
6.-and sometimes i get them even if the wind is blowing from the north (away from the lake);
7.-usually waves are located around a slope or mountain range but as i see, also at flat surfaces;
8.-so this means that even if waves are stationary, thermals can drift above them.
9.-this does not happen in many places; it takes some sort of special situation like the 1 i find at this specific place;
10.-but as i said, it is necessary to have a vario like mine that tells height and sends tones that tell if the plane is climbing (and how fast depending of the pitch and frecuency of the tones) to pinpoint their location.
11.-even if they are stationary waves, are linked to fronts: they depend on the front that pushes the air inland.

Posted by phil alvirez | Oct 14, 2015 @ 06:10 AM | 10,529 Views
slow start
1 trick that i have learned with the umx rad is to have a slow start. launch and run it at low throttle for 10 seconds, then accelerate at whatever speed you want. before i learned that, i have experienced unexpected cut-offs at about 5 seconds after launch, with the consequent dive and crash. i guess somehow the esc can't handle the surge. this happens only at the 1st flight after plugging-in a cell. now doing this it does not happen anymore.
https://www.rcgroups.com/forums/show....php?t=2089760

Posted by phil alvirez | Oct 12, 2015 @ 07:14 AM | 9,710 Views
well, after the most enjoyable time when i catched great thermals, i found my plane again into another situation where it drifted through a wave for some time and then decided to stay at the point where the lift was strongest. it drifted with the wind so brought it back and catched another thermal and drifted again. started at 200 meters and climbed to 330, so decided it was enough and began a return and descent. all seemed ok, but when it was near the field at 180 meters high it stopped sending signals from the vario. it was not beyond the range, but didn't know what that could mean at the time. as i was lying flat on my back through all this time i decided to stand up for the approach and landing, so i stood up and when i looked back at the plane it was nowhere to be seen. it was about 10 seconds. gone. in clear sky. i think it dove vertical, as when you turn off the radio by mistake. the vario is supposed to send a warning of low batteries, but i didn't hear it. not only that, it also had a low volt warning that vibrates, and it saved my plane last time, but i didn't feel it this time. later realized it had been in the air for 45 minutes. the other day when i almost lost it, it did 35 minutes.
>>>>An update: nov 14, 2016: after reading the manual again, i noticed this:
it really tells when the battery in the plane-or the battery in the receiver-is low by saying this:
“Battery Low”

# another exhilarating experience in thermalling

Posted by phil alvirez | Oct 06, 2015 @ 10:52 PM | 9,445 Views
yesterday i went to our field at noon. it was overcast, and the windmills in the way were still. when arrived, there were clouds all over and almost no wind, so i launched my Maverick 3 (a 2 meter electric sailplane) that has vario, and climbed to 200 meters (440 ft), which is the height that makes easy to catch thermals for this size of airplane, and immediately began to get beeps that tell that there is lift, so swept the area. lift was at a corridor across the field from where the breeze was coming, a so-called wake, that i have experienced here some times before. then. after some time, i began to turn at the point where there was the strongest lift (the highest tones) and in short time i reached 351 meters (1,168 ft)! i could not believe my eyes (or should say: my ears, as it was the vario that told me the height). i never had an airplane so high. and still i could see the plane and what it was doing. but was so tiny! the good thing of having a vario is that now i know how high it is at any time. before, without it, my estimate of height was out of reality. anyway, now i began to worry at loosing the plane and trimmed it to go down, but still kept getting the tones that it wanted to climb. had to give it 'down' signal until i watched it increasing its speed, but was careful that it was not too fast as it could loose its wings. it was quite a fight, but eventually i managed to bring it down to 200 meters. and then the low voltage alarm went off! i had to hurry it down and land. then at home i checked the battery: it was down to 9%! i barely made it.
the flight was 35 minutes, but could stay there for a long time. it was good that i decided to bring it down to 200 meters, otherwise i would loose it due to low battery.
some say that flying is an adventure: you never know what may come. sometimes is the agony and the ecstasy.
still, i was lucky to have such experience and having a happy ending.