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phil alvirez's blog
Archive for January, 2013
Posted by phil alvirez | Jan 24, 2013 @ 01:49 AM | 5,546 Views
when you get into 3d, 1st you want to learn to fly without crashing too often. of course, using epp will cut your training time considerably. once you don't crash too often, and your crashes are not catastrophic anymore, then you can think of improving your plane's performance. you read or hear from other guys talking about lighter planes performing better. sometimes you even watch them flying and speculating about it. then you know that you would like to build light so your plane helps you to do things easier. but how far can you go? when are you passing the boundaries of building light and getting into building fragile? and if you fly at a place where other guys fly at the same time and some are sort of kamikaze hunting for targets, you don't want to build fragile, even if you don't hit hard anymore. so, 1st you decide if you are going to fly only when there is no danger of midairs and build light, or to fly whenever and build strong. then, you begin building planes each 1 lighter than the 1 before. but you have to decide when to stop. that is, if you still have ideas on how to save a few grams without the plane disintegrating in mid air. but it is lots of fun. for instance: when i began building 'compact' 3d (24" ws, 100 gr auw), and using 6mm epp, my 1st plane ended up at 100 gr auw with a 2x300 pack (lipo). with the motor developing 140 grams of thrust on 2 cells, its power-to-weight ratio was enough to do 3d comfortably. then i went further and built a 2nd 1 that weighed 85 grams. what a difference! it flies slower, that gives me more time to think what am doing, so it's easier to do anything. when this happens, you don't want to go back to the heavier 1, that you can fly when the place is crowded and you don't care much if something happens, and also because it can take more punishment. but that creates 2 separate categories. so maybe it's good to keep both to fly depending of circumstances.
Posted by phil alvirez | Jan 19, 2013 @ 03:43 PM | 4,636 Views
i have shown before some plastic models from my son. now he has released a post here http://www.track-link.com/forums/new...ral/43435/flat. where you can see them. they are around the middle of the post, and he will be showing 1 by 1, with historic details and the camouflage he used on each 1.
i hope this will be of some use (or entertainment) to you all. some drawings (the 1s framed) are by me. he started doing plastic models in the 80's, when i owned a hobby shop in vancouver, and he had free access to materials and models. now you see how that evolved.
Posted by phil alvirez | Jan 12, 2013 @ 03:12 PM | 5,436 Views
Phil's Thermal Rex, or Phil's Rex for short, is a hybrid from a fuselage of the scale ASW 28 sold by hobby king. see
http://www.hobbyking.com/hobbyking/s...ider_PNF_.html
and the full size: http://www.easternsailplane.com/east...hleicher/ASW28
the reason why i choose this fuselage is because the looks are like science-fiction but it is very much like the full size. although i did not use the wing shape (especially the wing tips).
(i will be adding data at the bottom of this thread)
the new balsa wing it is a 2mt wingspan, 460 sqin, 543 gr auw w/2x1300 lipos; naca 6409 airfoil.
i used the foam fuselage and tail, and avionics, and designed a woody wing with larger area and an undercamberer airfoil for slower flights.
i got the whole plane and decided to try it as is, before discarding the wing. and boy, was i for a surprise! it falls into a stall and a spin unexpectedly, and i crashed it several times, breaking the nose and reinforcing it, until i throwed away the wing and started my own. fortunately with it the plane is now stable and predictable. originally it comes without dihedral, contrary to the full size, that has some. as the stock was too unstable and prone to snap roll, i added dihedral as per the full size and this helped a little bit; then increased the chord, adding area to the trailing edge, which helped more-but still was a handful. then it was when went into the balsa wing. it has a planked leading edge, polyhedral, and is covered with...Continue Reading