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Paper Airplane Designs

foldnfly.com

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Re: Paper Airplane Designs

#211

Post by dotancohen »

lmm wrote: post #177
r00fus wrote: post #161

Earlier quoted context omitted.

I wonder if this justifies the US adherence to the imperial standard - meaning it acts as a basic barrier to entry for other countries who use the "world" standard.

Compatibility usually gains you more than you lose. If you can't make US planes with parts from the rest of the world then that does mean other countries can't make US planes, but that also means that the US manufacturers can't import parts from elsewhere.

The F-35 has components made all over the world, but was designed in the US. Is that plane metric?

Re: Paper Airplane Designs

#212

Post by lmm »

dotancohen wrote: post #211
lmm wrote: post #177

Earlier quoted context omitted.

Compatibility usually gains you more than you lose. If you can't make US planes with parts from the rest of the world then that does mean other countries can't make US planes, but that also means that the US manufacturers can't import parts from elsewhere.

The F-35 has components made all over the world, but was designed in the US. Is that plane metric?

I would assume/hope so? Lockheed of all companies should be on top of that after the mars probe incident.

Re: Paper Airplane Designs

#213

Post by dotancohen »

simonsarris wrote: post #3

In the 90's I went to a small middle school, the 8th grade class was 21 people. Once, the school had a contest in the indoor gym, we each designed paper planes and the one who flew it the farthest won a prize. We argued with teachers over an allowance for a little bit of tape, which some of us used just as nose weight. However, each kid was the one to "fly" his own plane, a big oversight. Almost the last kid, when it…

I did the same thing in eighth grade. Put my toes on the throw line with an unfolded sheet of paper, and crumpled it right there on the spot. We were judged on both distance and "straightness" of flight, I believe that I won on both counts. However, I was disqualified for "not being an airplane" though nobody, not even the teachers, could tell me why. I was hoping to justify my stance that golf balls produce lift, so therefore my ball should produce lift and be considered an airplane as well, but there was no interested ear to appeal to.

Re: Paper Airplane Designs

#214

Post by sanityinc »

offsky wrote: post #138
Endy wrote: post #125

Earlier quoted context omitted.

My only problem with this website is that when I used it with a class of students, there were pornographic advertisements in between the plane types. That was really upsetting. Please reconsider your ads.

That is very odd and not what I want. It’s just google Adsense. You sure your computer doesn’t have spyware?

You can control which categories of ads will be displayed in your Adsense account settings. It shouldn't be necessary in a civilised world, of course, but there you go.

Re: Paper Airplane Designs

#215

Post by sandrobfc »

I sure could use this 25 years ago to impress the whole school... However, I hardly can see how some of them get to fly straight, but I think that it's a question of trying it out myself.

Re: Paper Airplane Designs

#216

Post by j2kun »

dmerrick wrote: post #118
j2kun wrote: post #114

One trick I always used but never understood why it worked: When you add a crease to the paper airplane, (say, folding a square corner in on itself at the nose or the tail), it weighs down that part of the plane. So if your plane is pointing up too much, you add a crease in the nose and it flies more level. But why should adding a crease increase the weight of one section of a plane? You're not adding any more paper.

You are moving the center of mass of the paper. Imagine balancing a pipe cleaner on your finger, should be pretty easy, right? Now add a bend and see that you have to reposition the pipe cleaner on your finger

I'm moving the weight more toward the center of the plane, but the plane "appears" heavier in the front. This is the opposite effect, no?

Re: Paper Airplane Designs

#217

Post by tonyarkles »

TylerE wrote: post #109
tonyarkles wrote: post #10

Earlier quoted context omitted.

Hmmmmmm. I wonder if X-Plane would be capable of simulating that... they basically do an FEA model of flight, although I’m not sure if it would scale down appropriately.

X-Plane really only SORT of models flight. There is no actual FEA or fluid simulation of any kind. The airfoils are canned data lookup. So you can't make something out of polygons and have it wactually "work". It'll fuselage calculate drag based on frontal area and the coefficient you specify, but that's about it. This approach works well for real planes since 99.999% of them use standard NACA airfoils that are well…

Oh! Thanks! I've flipped it into the "airflow visualization mode" but didn't know that it was based on lookup tables!

Re: Paper Airplane Designs

#218

Post by tonyarkles »

Alupis wrote: post #28
tonyarkles wrote: post #10

Earlier quoted context omitted.

Hmmmmmm. I wonder if X-Plane would be capable of simulating that... they basically do an FEA model of flight, although I’m not sure if it would scale down appropriately.

Flight physics don't scale down (or up) well. It's the predominant reason small airplane and quad models have enormously unscalable performance characteristics and abilities. Making it bigger doesn't "just work"... same for the inverse.

Isn't that mostly due to the square/cube nature of scaling things? E.g. your wing area changes with the square of your scaling factor, but your mass changes with the cube of your scaling factor?
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