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phil alvirez's blog
Archive for October, 2011
Posted by phil alvirez | Oct 31, 2011 @ 07:14 PM | 4,598 Views
chapter 4-books!i recall seeing my mother always with a book. any free time she had, she was reading. and that made me try to decipher those signs on the paper, until i learned to read. and that opened a window where the sky is the limit. as soon as i was allowed to go to the library, there i was, exploring all those treasures, windows to the fantasy, where i could learn and dream of all that i wanted. then i discovered books on aviation, first full size, then models. and magazines: Model Airplane News, with all the models, plans, theory...like Charkes H Grant's Design Forum, where i learned how to design my planes. well, he provided proportions, but also let me experiment with structures and airfoils, learning to plot them. and about coordinates, polars, all the mysteries unveiled. then learned about the books of Frank Zaic, with hundreds of plans, structures, more theory. there was no room for more in my life. and so far...still there is no room for anything else. there is no time to try all the ideas. when i corresponded with another great guy, Jim Clem, we agreed that we had to live hundreds of years to be able to try all the things that we dream to do. so little time...although now we have this net thing that goes beyond the wildest dream. today, we are living in a world where science-fiction has become reality. remember Dick Tracy's wrist radio-television that seemed too fantastic? now we all have celulars and see them as the most natural thing.
Posted by phil alvirez | Oct 21, 2011 @ 07:35 AM | 5,249 Views
from my years on modelling, the most valuable thing i have learned is not to say "1 last flight", for if i say so, it is going to be the last flight! if free flight, the plane goes into a spin and crashes, or gets into a thermal and is gone forever. if control line or remote control, any of the zillions of possibilities that something may go wrong, will go wrong.
it's not being superstitious. it's a fact.
so, don't tell the gremlins that.
now, if you don't believe me, i invite you to try saying that and see if you come out clean. or if you believe that, please don't feel free to comment here, because i know this thread will be overcrowded with messages.
instead, say : "another flight", and at the end of it, say "that was the last flight of the day", pack your things, and get back home. you will have better chances to do it with your plane in good shape.
just in case the gremlins are listening.
Posted by phil alvirez | Oct 13, 2011 @ 06:17 PM | 5,066 Views
am not superstitious. and still i want to believe in gremlins. please notice that i said that i 'want' to believe in them, not that i really believe. let me explain: some say that they are mischievous creatures that have great pleasure on making us upset. so i decided to laugh at adversity. whenever something unexpectedly goes wrong, instead of giving them the pleasure of seeing me upset, or discouraged, i laugh. so now, they are the ones who get upset because they don't see me upset. how about that?
the best thing is that it has become a habit to laugh at everything that goes wrong, and now i really laugh at it. honest. and that has changed my view of life. someone said that everything is small stuff, so why get upset? the best thing is that now am a happy man, that few-if any-things put me out of balance-and that momentarily, and then i think that they may be watching, so here i am, laughing at adversity, and soon i forget it. think about what is really a tragedy, and then you realize that almost everything is not worth getting upset. and even if sometime something is really a disaster, think about that old zen proverb that says: 'now that my home has burned out, i have a better view of the sky'.
smile. they may be watching.
Posted by phil alvirez | Oct 10, 2011 @ 09:36 AM | 5,003 Views
i got this gear box made specifically for the 1015, it takes didel gears- pinion: 12t; spur: 60. the plastic housing weighs 0.23 grams.
i have field tested it and runs fine. i modified it to take plywood beams to increase the support area but will get another with longer beams. the prop shaft is 1.5mm and takes ball bearings. you see it here with a gws 7/3.5 trimmed to 6" due to limitations of the fins but i think it can handle the full 7" prop.
>>> now i have done more field tests with this gb. when using it with the clipped 7/3.5, and with the canard shown, as the plane is sort of fast flier, it takes full throttle most of the time. i have been testing it also with another plane that is slower (my owl), and with a full 7/3.5. with it, throttle for climb is 60% and cruising around 50%, and am getting 6 minutes flights. seems that this high 5:1 ratio does better with large props for slow flying.
update: these are the news:
it has an official part number. the manufacturer calls it "bimRC PA-5:1", and it is in the final development stage and will have other versions.
nov 13: finally the housings are available. see details here:
http://www.rcgroups.com/forums/showt...6#post19865005 (post 240)...Continue Reading
Posted by phil alvirez | Oct 10, 2011 @ 09:27 AM | 4,658 Views
some gear boxes have mounts that are too fragile-or not practical. i have made some from plywood, with beams, very much like the ones on the 8.5 motors from horizon-or the ones used with engines. at top, latest from hk: EP-BRUSH8 gb w/12-68 t; 'black' 8.5x20 motor; i added 3x20mm cf tubing and 1/16" ply for beams, trimmed shaft; shown w/ 1933 adapter for gws 6-7" props....Continue Reading
Posted by phil alvirez | Oct 07, 2011 @ 10:45 AM | 4,618 Views
with the snowfox and snowgoose i was trying to see what difference sweep forward or back makes. after evaluation i learned that even if both fly satisfactorily, the goose with sweep back is more stable and predictable. there is a marked difference. it is not only that the fox with sweep forward is more maneurable, it is less stable. nothing comes from nothing.
more maneurability=less stability
there is an interesting article on the issue here:
http://www.rubber-power.com/Articles/ftaf3.pdf
the author mentions that every 10 degrees of sweepback make the same effect as 1 degree of dihedral. he said: "In fact a common rule of thumb in airplane design is that 10 degrees of sweep has about the same stabilizing effect in roll as one degree of dihedral". so the sweep forward acts like negative dihedral. also, with the Mk II versions of both models, at the beginning i did not glue the wing fillets and flew them, and added them later. the effect was that both became more stable with them. i guess that these fillets have same effect as sweepback-or added dihedral.
Posted by phil alvirez | Oct 01, 2011 @ 11:09 AM | 4,474 Views
Chapter 3.-my first car.
At the time, public transportation was good. We could go anywhere. but when a fellow worker at the office told me he was selling his car, that he kept in great shape, and the money he was getting, I decided to buy it, and brough him the money. it was a 1951 studebaker that looked as if it only needed a prop to take-off!
we did the paper work, he handled me the keys, and then...well, i had to ask him the details. like how to start it. the starter worked when depressing the clutch pedal to the floor (something i found many years later in my 1985 firebird). the fact was that i had not driven a car yet. i was into flying, and had some hours behind lightplanes, and even DC3, but was never interested into surface vehicles. driving home, with that clutch so sensitive, and the trafic so close around me, i had to stay in the car for 15 minutes before i could walk, as my legs were so shaky! took me some days to get used to all and feel comfortable. as i grew up flying airplanes, with safety belt of course, i felt unsafe driving a car without it, so i managed to get safety belts from the airplanes that were being overhauled, and installed 2 sets on the front seat (bench seat, remember those?). people around couldn't stop making fun of me. at the time not even race cars had them. some racers began using those egg-shell looking helmets, but that was all. since that car, i kept adding belts to my cars, until the government made it a law.
but i will never forget that wonderful car that looked like an airplane.