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Posted by phil alvirez | Jan 27, 2016 @ 04:10 AM | 1,547 Views
i want to talk about another source for lift, that i have learned recently. it is a narrow band across the wind.
more specifically:
a stationary invisible narrow band across the wind, that generates lift.
this happens to me at a flat field with no elevations in sight (the only obstacle is a row of trees), located at 5km from a large lake. there is no wind blowing at the band mentioned; it is clear air all around; the invisible band does not drift (stationary for a long time). i know is there because the vario sends beeps that let me pinpoint its location; the wind does not penetrate it, and the band generates lift; i know this because i can keep my plane at that level forever. i have to keep the plane doing s turns within it to stay on the lift. if i turn the plane across it (facing the wind that is found below and above) the plane flies away of the band and sinks. the area is a narrow band across the wind (but wide enough to let my 2 meters sailplanes do full turns) that blows down here, and is present only at certain level (some 200 meters). ahead, behind, and below it, there is wind and the plane sinks no matter which way i turn, but drifts with the wind. and above, there is wind and sometimes i catch a thermal and drift with the wind.
considering the complexity of the situation, how it may be called may not be easy to decide. i have been using 'wave' as it runs across the wind, to diferentiate it from 'streets', that run along the wind, but maybe this makes things...Continue Reading
Posted by phil alvirez | Jan 20, 2016 @ 05:45 PM | 7,182 Views
when i studied aeronautical engineering in the 60's, i took meteorology. 1 of the things we had to learn was how to make a report of the direction of wind at several levels, with the purpose to tell pilots what direction of wind at different heights they could encounter. it is critical, as when climbing you may meet wind from the north and suddenly it changes to the south. it may be particularly critical for light planes. wind may flow at different direction depending of the level, and runs in layers, like blankets. if you have light models you may experience these sudden changes in direction. anyway, in those days we had to go to a small isolated room at the airport and inflate a large red ballon with hydrogen, as helium was not available. we connected it to the tank with a valve and let it blow to the point when the amount of gas made the baloon become buoyant while supporting the weight of the valve. this gave it the buoyancy to climb at certain rate. then we prepared a transit theodolite, pressed a switch that started a timer and released the ballon and aimed at it and pressed a button every minute. this punched a hole in a paper disc and as the timer activated a spring, each hole was punctured further from the center. it ended up as sort of a spiral, if the wind changed a lot. this way the experts could decypher it and make the chart of superior winds. the thing was that we had to do this in an isolated room because hydrogen is explosive, and we had to be extremely careful doing this as it could explode in any moment. some times the ballon just blew, and was a shocking experience because at that moment you felt that you were going to die in flames. to make things worse, there were moskitos around, and the silly beasts took the red baloon as something that they would like to pierce and then it blew.
a horrifying experience i would say. thankfully now with satellites and computers all over this routine belongs to the past.but it was something that you will never forget.
Posted by phil alvirez | Jan 18, 2016 @ 05:23 PM | 2,624 Views
once my plane disappeared in sudden dense fog and lost it. i never expected something like that. i never saw anything like that, or heard about it. there is a post somewhere down in this blog (page 4, Aug 03, 2013 ) where i mentioned it in detail.
it was not until now i found an article that mentions the situation. it says:
Coastal fog and low cloud can come in very suddenly. Cliff soaring can be full of hazards! I was amazed recently when on the east coast to watch a bank of sea fog reduce the visibility from 10 kilometres to around 100 metres in less than a minute (although this was not in fact a sea breeze effect)

this is taken from here: http://www.weatherjackwx.co.uk/tutor...20breezes.html

as i was flying inland, also found this in the same article:

A strong sea breeze front could move up to 50 kilometres inland
so now i understand what happened to me, although it is a rare event.
Posted by phil alvirez | Jan 14, 2016 @ 09:54 AM | 2,124 Views
1 of the most valuable things i have learned, now that am dealing with electronics and having to program everything, from the answering machine to the range, and of course our radios, is that, if when programming something it does not work, is trying again.
don't know why, but it works many times.
don't get scared, just try again.
maybe won't everytime, but it's worth trying it.
Posted by phil alvirez | Jan 11, 2016 @ 01:41 PM | 1,576 Views
conclusions (revised)
based on the opinions from very knowledgeable people, am compiling the data about charging lipo cells in parallel.
this is what i have learned from all the comments from experts:
regarding the installation:
use cells spot-welded (or with tabs and then soldered)
if soldered in parallel you can't check the condition of each cell;
if is series you can, but you have to add 1 extra wire coming from each cell (this is the common way we find in lipos).
with this extra wire each cell is also charged and balanced.
with cells installed in a battery box and connected with springs, there is the risk of having false contacts, but you can charge them individually and keep the pack balanced.
you use parallel connections when you need to keep single cell voltage for the pack, and series if you need to increase voltage to the sum of all.
when using nicads or nimh you can live without checking their condition, as they are tolerant to disbalance.
in the case of cells in parallel, as you can't check volts of each cell, i heard from dickw that you can get an idea of the pack condition by measuring the charge they take and keeping records, so you can see if the pack is going down and needs to be dismantled and you can check each cell and replace the one(s) gone bad.
for this you need to have a charger that measures the charge.
but could be that i did not get it right in something, so i would like to hear your comments about this
the reason for this quest was that i learned that the radio am using has the option to use lipos in the transmitter, and this works for some guys. see their comments; http://www.rcgroups.com/forums/showt...3#post33698877
Posted by phil alvirez | Dec 21, 2015 @ 03:24 PM | 2,955 Views
today i was sent this and tried it. how about you?
it could be good to improve your reactions when flying your plane.
https://www.justpark.com/creative/reaction-time-test/

enjoy!
Posted by phil alvirez | Dec 20, 2015 @ 02:05 PM | 3,199 Views
those were the days!
i was getting memories of my early days (about 5 years old) when we lived downtown in a 1 level apartments building that had gates so only the residents children could play around. there was a paved street, with sidewalks, and i rode around on my tricycle. there was a fountain with white and blue tiles and 4 frogs that were spitting water, and some gold fish too. the house had a patio layed with bricks and a trellis with a pink bougainvillea and at night there were trains of assorted colors (worms that glow at dark like fireflies) and sometimes fireflies too. there was another patio at the back where my mother washed the cloths and used the same tin tub, that she filled with water so the sun warmed it up for me to bath in the afternoon. i just got in and played with my rubber ducklin and she sung sons to me when she bathed me. 1 of them was about swallows, that came in spring and left in fall, and everytime i cried and the tears ran all over my face and body to the water. whenever i asked her to sing it she said that i cried and i said that i liked it anyway. memories that have enhanced my life...
Posted by phil alvirez | Dec 20, 2015 @ 01:26 PM | 3,157 Views
i started a thread on the modeling science forum about a new adhesive that could revolutionize assemblying and repairing models.
see it there and bring ideas and links if you can.

http://www.rcgroups.com/forums/showthread.php?t=2563452
Posted by phil alvirez | Dec 12, 2015 @ 07:00 PM | 3,553 Views
from the beginning, i always have placed a sticker with my name, address and phone on every plane.
for those who don't believe it works, i can tell you that, well,sometimes it does. maybe rarely, but it is worth doing it.
from my years of free flight, to these years of radio control.
last year i lost a 2 meters sailplane in the fog, and 2 months later a farmer driving his tractor to our field brought it back. i thanked him and later checked the plane. as it was exposed to the elements for so long, and as it crashed and the wing split and the covering lifted, water got all inside. the only thing i could salvage was the spinner, prop, and motor.
then about 2 months ago i lost another (my best) sailplane, this time due to running out of power. i was so deep into thermalling that by the time i noticed something was wrong it was too late. am not sure if i didn't feel the vibrations of the low volts alarm due to the excitement of thermalling, but when i stood up (i was lying on the grass for about 45minutes) and tried to see it again, it was gone.
searched but to no avail. then 5 weeks later a phone call from a nice fellow brough it back, this time in not so bad shape. extensive repairs after drying it out, was ready for the next window in the weather. and this happened today. it flew as well as before. great satisfaction to see it flying again. so, sometimes miracles happen.
post your name and phone on every plane you own.
you never know...
Posted by phil alvirez | Nov 20, 2015 @ 09:23 AM | 3,732 Views
at least we at the northern hemisphere are facing the season when it is too cold and windy to fly our planes, and it will not improve until maybe the end of april, so we have to aim at something to do with our time. so, maybe posting some anecdotes will entertain the other viewers, for instance? i have been doing so for some time, so why not you too?
Posted by phil alvirez | Nov 11, 2015 @ 07:07 AM | 4,076 Views
i have been compiling opinions on the subject:
1.-"All sailplanes are gliders, but not all gliders are sailplanes.
2.-A glider is any airplane without an engine.
3.-A sailplane is a glider that is aerodynamic enough that sustained flight is possible by using rising air currents to maintain altitude, or even to climb.
4.-A glider that is not a sailplane is not expected to maintain altitude or travel very far. During world War II the US, Britain, and Germany all used large troop carrying gliders. These could in no way be called sailplanes.
5.-The words are virtually interchangeable but generally a sailplane is a high performance glider. Some gliders have engines to allow them to takeoff or stay aloft longer but they are referred to as motor gliders. Usually a glider has a glide ratio of less than 20:1. 20 feet forward for every foot down. Some sailplanes have glide ratios of more than 50:1 but there is no clear cut definition of the glide ratio when a glider becomes a sailplane.
6.-They're interchangeable. It's only a matter of semantics.
7.-From a certification point of view, a sailplane really doesn't exist.
8.-The license in your pocket will say glider on it.
9.-A glider is designed to descend in a controlled manner, whereas a sailplane is designed or intended to be able to climb in lift."

in our case with models, as powering a glider/sailplane to get to altitude, mostly with an electric motor, we call them ' electric sailplanes (or electric gliders').
i myself call my planes 'sailplanes' because they can get into thermals. and the 1 i agree most is #9.
anyway, i think that we can call ours whatever we find more to our liking. as long as we understand what kind of planes we are talking about.
above all, enjoy them.
Posted by phil alvirez | Nov 06, 2015 @ 09:11 AM | 4,311 Views
i started with thermals when my 1st plane (free flight) got into 1 and went up and away. from then i began to use a fuse for dethermalizing and was able to get back my planes most of the time. then came radio and got into sailplanes, with which i was able to hunt for thermals. climb to about 45 to 60 degrees and watch the plane for jumping up and turning until got it. when drifted too far brought it back and search for another. no more than 10 minutes. fun!
then recently got a vario and a new dimension, as i am able to 'see' the thermal-or whatever makes my plane stay there or climb. but then i faced another situation, as now i could stay longer, so got devices to warn me of low voltage. ended up having 1 that sends vibrations, and another that shows volts of each cell, and sends beeps when reaching the voltage that i decided to be the lowest safest. the smaller (vibrator) fits my planes with reduced space, and the other the larger 1s.
but once on a long flight i didn't feel the vibrations and lost a plane. am not sure if the device failed or its battery went down or i just didn't pay attention to it, but now am trying to take measures to avoid this to happen again, like bringing the plane down at a higher voltage warning, and above all, not staying up for so long.
and will keep enjoying the most enjoyable (to me) experience.
these are the alarms:
http://www.hobbyking.com/hobbyking/s...15Mhz_FM_.html
http://www.hobbyking.com/hobbyking/s..._mAh_V3_1.html

have fun.
Posted by phil alvirez | Nov 02, 2015 @ 08:20 AM | 4,181 Views
this what i have learned about the rad's duration:
there are several ways it could reach the end of its serviceable life:
1.- wearing out the brushes of the motors, be the 1 that powers the plane, or those at the servos;
2.-the resistive ink on the PCB wears out as the wiper slides through it.
the symptoms for the motors may be: for the main motor, it may just get weak, or runs uneven, even sometimes refuses to re-start in flight;
for the servo motors, the servos may run uneven or sometimes don't re-start in the middle of the flight.
and is practically impossible to check them unless having specialized equipment and may be removing or disconnecting them.
for the track on the pcb you have to remove the servo, which is sort of delicate task and also have to remove the brick.
(this is what happened to 1 of my rads, so maybe this part is the 1 that wears out before the others).
so, whenever your plane starts to behave erratical, or any of the servos stop functioning (and this may happen in the middle of the flight), it is time to get a new brick-or a new plane.
these are not complaints. to me this plane is the most wonderful i even flew, and intend to keep using it despite these facts.
just to any1 to consider this in case it happens to you.
http://www.rcgroups.com/forums/showthread.php?t=2089760
Posted by phil alvirez | Oct 15, 2015 @ 04:31 PM | 4,813 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.
anyway, a most...Continue Reading
Posted by phil alvirez | Oct 14, 2015 @ 07:10 AM | 5,857 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.
http://www.rcgroups.com/forums/showthread.php?t=2089760
Posted by phil alvirez | Oct 12, 2015 @ 08:14 AM | 5,396 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.
conclusions:
1.-what i learned from all this is that thermalling is addictive: you get dizzy catching and staying in a thermal and loose sense of the time spent, and just want to stay there. it is especially critical if you fly alone.
2.-it is necessary to set a timer or have...Continue Reading
Posted by phil alvirez | Oct 06, 2015 @ 11:52 PM | 5,429 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 531 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.
Posted by phil alvirez | Sep 25, 2015 @ 01:50 PM | 5,717 Views
umx radian: http://www.rcgroups.com/forums/showthread.php?t=2089760
for those of you fans of the lil rad am starting a thread where am bringing the posts i have placed in my blog, that are scattered all over the several pages, so you don't have to search.
http://www.rcgroups.com/forums/showthread.php?t=2508435
Posted by phil alvirez | Sep 23, 2015 @ 09:42 AM | 5,094 Views
the only way i knew of going up without motor was with thermals.
(of course there is a way of staying up at a slope, but that is not the subject of this thread).
the purpose here is to seek for means to climb at a relatively flat field.
until recently i was of the idea that thermals were the only mean to do so, but when i moved to a new field, and got a vario that tells with beeps when the plane is climbing, i could search for lift and practically 'see' it as if it were painted in bright color. and then 1 day with clear sky my plane began to find lift in a long rectangular area across the field. there was a light breeze but lift was across it, not a circular pattern. i used it for as long as i wanted. it didn't move. it was an exhilarating experience. i couldn't believe my eyes-and my ears! i had to trim the plane down and drift far from the area to get out of it.
then i began to post at several forums and learned that it was a wave. there are several threads where i got answers.
eventually i moved them to my blog but now am starting this again here to see if there are more contributions and add data as i get it.will talk about my experience, but 1st will tell how is the place where i moved recently and am experiencing this: it is all flat farm land around, located at about 5 km (3 mi) at the north of a large lake, from where the wind blows most of the time. the 1st time i just explained it before, and for several days it didn't happen, until now again in clear sky, but this time stronger wind blowing from the north. and there were several waves that moved with the wind so i had to drift with them. altitude in both cases was about 200 meters (450 ft).
will bring more data as i find more experiences like this, but all polite, positive and to the point contributions are welcome.
Posted by phil alvirez | Sep 08, 2015 @ 09:23 AM | 5,789 Views
i have been an enthusiast about flying on thermals, since my days of free flight, and now more with sailplanes, radio and vario at my hand am having the time of my life.
i have been compiling data on the subject, and as i said, with the aid of the vario am learning still more about them.
as far as i knew, thermals form from the ground and rise to the condensation level and become clouds. their shape could be bubbles or a column.
but now on clear sky am getting some lift that i find in areas like waves that run across, like some clouds that are lines that run parallel. this i 'see' because am using a vario that sends beeps when the plane climbs.
has any1 experienced this?
is there any link about this?
for more details i started a thread here:
http://www.rcgroups.com/forums/showthread.php?t=2487246
and if you have any info please bring it here.