Posted by phil alvirez |
Jan 30, 2011 @ 08:06 PM | 9,607 Views
snowflake 22"-120 sq in wing area
48.5gr auw, 6400 brick, brushless 1015 geared motor-gws 6/3 prop.
i flew it today at the gym. gear box from kenway. it takes some work fitting the motor to the box, though.
for more details on the motor: http://www.rcgroups.com/forums/showthread.php?t=1360585
(see post 105)
1mm foam all over; boom is 4mm od carbon fiber tubing from bp hobbies.
it was a geat day: 2 maiden (this and the Elf 24"), both great! longer tail moment than the Elf, shorter nose. the brushless motor runs great, with lots of power. and it pulls that large gws 6/3 prop well. the slowest plane i have, and have ever seen, so the name was cast right.
here is the link where i will be adding data: http://www.rcgroups.com/forums/showthread.php?t=1386674.
Posted by phil alvirez |
Jan 30, 2011 @ 08:05 PM | 9,520 Views
Elf 24"-144 sq in wing area.
the largest of the series with 4site/suk components.
it began with the 18" size, and has been growing to 20 and 22, and still there is power available, so i went for the next size. auw went from 48 gr of the 22 to 54 grams. same materials, structure (except 2mm instead of 1), components. i flew it today at the gym, and still does not require much throttle. nice take-offs, turns, landings, touch and goes. the motor is a 'black' from the 4site; 5.1" prop. it had a midair with a 4site, and came out with a cut at the leading edge, that a quick patch of invisible tape fixed.
i tested it outdoors in the cold and flies even slower and more floaty. when stopping the motor, it's the easiest to catch!
how big can it go? i guess it is the paper-thin foam that has almost no frontal area, that makes very little drag, and therefore it does not matter very much how large it is, as long as it keeps a very light wing loading. using material this thin places us at the absolute minimum, so close to the theoretical ideal that things are like daydreaming. it is when Schmitz explanation makes sense (see my blog-below, at the end of 'my goal is...').
an update: i fly it whenever there is no wind, and is the most pleasing of all. and there is enough power from the black motor.
for more details, see this thread: http://www.rcgroups.com/forums/showthread.php?t=1474402
january 12, 2011
Classic Elf 20" (stick-n-tissue)
100 sq in, 50 grams auw, for 4s/suk components.
i spent the past 5 weeks working as hard as i could, re-designing the structure of the Elf 20" for balsa stick and tissue, building it, and just finished it. i have been doing foamies for the past who-knows-how-long, and finally went back to balsa. i decided to have 2 planes based on same design, same basic dimensions, 1 foam, the other balsa, and compare them.
so far, what i have to say is that, as we could expect, foamies build way faster, don't require as much skills or precision; take more punishment, and are easier to repair. what i was not expecting is that foamies are lighter than balsa planes, even stick and tissue: the foam Elf 20 weighs 42 grams auw, and the balsa 50. now, i still have to fly them, to learn what the difference in flight is, although that has to be indoor at the time, and in a hurry, because the boys at the gym only let light stuff for a few minutes.(update: maiden flight: see the thread at indoor and micro models-link below)
>>here are some details of the build: airframe: same wing planform (20"x5...Continue Reading
Posted by phil alvirez |
Jan 04, 2011 @ 05:34 PM | 9,655 Views
when i returned to r/c, after some 9 years (i was doing painting, oil on canvas), first i reactivated my 2 elfs, the 36" and the 48", with the new technology. as i realized that i could make smaller airplanes, i got 1 park 250 motor and designed another plane for it (gremlin), and then heard that there was going to be an even smaller motor (park 180), so i designed an airplane for it. it was the Talisman. guessing the power, it came as a 24"ws, 6" chord (144sqin),weighing 140 gr. it was even better than my wildest spectations. with it i began an extensive program evaluating turbulators, with 2 identical wings, 1 of them with turbs and the other without. i measured speed with both, and you will find more at 'my goal...'. it was an exhilarating experience to see that all the work by Schmitz confirmed what i had been living for many years. there is more data on the talisman below, but it has been evolving through the time. i tried another wing with higher aspect ratio and sharper leading edge, first without, then with turbs, then added fixed flaps to increase area and slow it down-the turbs made it too fast for my taste (and for catching it).
then came the variations with pusher configuration. i will add that under the Talisman, at 'my goal is...' look for the notice in here when i do that.
About phil alvirez
my view of life: 'But I don't want to go among mad people,' said Alice. 'Oh, you can't help that,' said the cat. 'We're all mad here.' (from 'Alice in Wonderland')