topic Re: how would you model this blade ? in Libraries & objects

how would you model this blade ?

Rakela Raul — Wed, 05 Mar 2008 23:42:15 GMT

can you please direct me on how to model this blade??
it has a thin area, a fat area and the tricky thing is the 'twisting' of the one end.
thanku in advance

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 00:05:14 GMT

two meshes - one deflected up and over, one deflected down and around

Re: how would you model this blade ?

Rakela Raul — Thu, 06 Mar 2008 03:04:32 GMT

Thanku Dwight, I will give it a try rt now....i was expecting to get some sleep tonite, but I guess that can wait till tomorrow nite !! thanku again ..
i have noticed several times that i underestimate the mesh tool..., i didnt even think of it !!

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 03:10:06 GMT

The firm got shortlisted for three public art projects today otherwise I would model an example for you.

Trick: make your top mesh, then duplicate it and drop the central nodes for the bottom- this way the edges stay together.

Re: how would you model this blade ?

Anonymous — Thu, 06 Mar 2008 03:19:52 GMT

Hello Raul,
Never underestimate the the mesh tool.
For controlled organic shapes in Archicad
it is often the only tool that can do it.
I was looking at your image and I don't
see the "twist" in the blade itself.
To me it appears that the pitch is controlled
by rotating the entire blade about it's long axis
at the hub unlike a normal propeller blade which
is twisted within the body of the blade.
Peter Devlin

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 03:32:51 GMT

But I have an Otter prop here and the actual prop blade is quite flat - shaped like a wing with a tricky transitional twist at the base - unlike laminated wooden props from before WW2.

In Canada we had an airline pioneer named Max Ward who crashed his plane up North and built a prop. It is easier than it looks to build one - a saw, a drawknife and a spin balance.

At the Boeing museum in Seattle there's a shop drawing on cutting a block of wood to carve a prop. very pretty. Tried to use it to model a prop myself but too hard....

Re: how would you model this blade ?

Anonymous — Thu, 06 Mar 2008 03:54:21 GMT

Hello Dwight,
Which type of propeller blade do you think
most resembles the blade shown in Raul's image ?
You would agree that this relevant to how to model
this object. If it has a twist in the body of the blade
then you would have to change the plane that you
use as the X,Y plane of the mesh.
Peter Devlin

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 04:01:46 GMT

I'd make the blade like a wing and bulge the shoulder down into the pitch adjustment coupling.

Here's a set of profiles to consider:

http://www.greeleynet.com/~cmorrison/airfoil3.pdf

Re: how would you model this blade ?

Anonymous — Thu, 06 Mar 2008 04:21:11 GMT

Thank you Dwight,
Now both Raul and I have the the section fairing lines
to make this kind of blade.
As usual, you have taught me something. This time about propeller blades.
Now I wonder if you know something about submarine propellers.
They are different from normal surface boat and ship propellers
Thanks,
Peter Devlin

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 04:28:38 GMT

Of course they are different, designed to work underwater like that.

haha.

But I CAN tell you about sewage impellers.

Re: how would you model this blade ?

Rakela Raul — Thu, 06 Mar 2008 04:29:56 GMT

im not sleeping !! working on it...
if I dont put my hands on it, never learn...if I come out with something decent will post it.

Re: how would you model this blade ?

Anonymous — Thu, 06 Mar 2008 04:47:08 GMT

Hello Raul,
A modest suggestion. Instead of making the underside of the blade
by using negative values of the nodes for the top side, after you
have made the top side mesh, save it as a library part, copy
the code for the MASS command, type MULz -1 then paste the
code for the MASS command and after that type del 1.
This way is easier than doing all that typing and you have an
object that you can rotate about any axis to assemble the wind turbine.
You did post this topic in the libraries/GDL sub-forum and I know you are interested in GDL.
Peter Devlin

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 04:53:09 GMT

but the faces aren't symmetric and the node editing is all done visually in 3D.....

Re: how would you model this blade ?

Anonymous — Thu, 06 Mar 2008 05:11:00 GMT

Hello Dwight,
I assumed the faces were symmetric. It is late for me and
I will have to study the .pdf tomorrow.
Thanks,
Peter Devlin

Re: how would you model this blade ?

Mats_Knutsson — Thu, 06 Mar 2008 09:09:58 GMT

Peter wrote:
Thank you Dwight,
Now both Raul and I have the the section fairing lines
to make this kind of blade.
As usual, you have taught me something. This time about propeller blades.
Now I wonder if you know something about submarine propellers.
They are different from normal surface boat and ship propellers
Thanks,
Peter Devlin

In addition to your submarine propeller question to Dwight I also would like to ask Dwight if you also know how to analyze submarine propeller sound? We had an infamous submarine visit here close to Stockholm in the eighties, and we sill don't know if it was a US or Russian sub. The marine have some recorded sound but they are not clever enough to figure out who came to see us.

Re: how would you model this blade ?

Dwight — Thu, 06 Mar 2008 18:29:09 GMT

Depends who is listening.

The Americans make out the Russians to be bad guys, so of course they want to be superior - making less sound, but the movie Hunt For Red October, a tome of science and accuracy, indicates that sonar is inexact.

The American submarine, buoyed as it is by the hubris of inherant technological superiority probably is quieter. There's probably an undertone of "nyah nyah" in the American sound. "Throb… nyah… throb… nyah…raspberry sound… ruskies go home!!!"

The Americans teach their sonartechs to listen for steam jets, cracking donkey thigh bone piston rods and the clank of rolling vodka bottles.

Of course i am joking. The Americans have a greater tax base, a larger population and less domestic problems at home. They have more money to make a quiet submarine including rubber propellors. You don't see any web site where appealing American women doctors are signing up to be brides in Russia, do you?

There was one thing that told me volumes about the technical differences between these countries. At Expo 86, a "transportation" theme fair we held here in Vancouver, the Soviets [at that time] sent a spacecraft for exhibit. Looking at the command station, there was a fine, hand-tooled cowhide document pouch holding a large TIN [!] of Estonian bacon, a big hunk of dense black bread [floating zero-gravity CRUMBS], and a GLASS bottle of vodka. Their Soyuz [?] boosters deliver a higher payload than the American Apollos - and their use to launch tins and bottle while the Americans made powdered tang and the tiny calculator tells me that they can use brute force to get things done whereas a quiet submarine propulsion system is a matter of finesse.

Re: how would you model this blade ?

Rakela Raul — Thu, 06 Mar 2008 19:07:50 GMT

Thanks to P & D for helping me out lastnite

I am absolutely not proud of the outcome, not an object for the just released AC11 hotfix lib for sure, but from a couple of miles will not be that bad !!!

I learned a huge deal in the process and now im kind of ready for something similar !!!!!.

thanks again

Re: how would you model this blade ?

Mats_Knutsson — Fri, 07 Mar 2008 08:06:20 GMT

Dwight wrote:
Depends who is listening.

The Americans make out the Russians to be bad guys, so of course they want to be superior - making less sound, but the movie Hunt For Red October, a tome of science and accuracy, indicates that sonar is inexact.

The American submarine, buoyed as it is by the hubris of inherant technological superiority probably is quieter. There's probably an undertone of "nyah nyah" in the American sound. "Throb… nyah… throb… nyah…raspberry sound… ruskies go home!!!"

The Americans teach their sonartechs to listen for steam jets, cracking donkey thigh bone piston rods and the clank of rolling vodka bottles.

Of course i am joking. The Americans have a greater tax base, a larger population and less domestic problems at home. They have more money to make a quiet submarine including rubber propellors. You don't see any web site where appealing American women doctors are signing up to be brides in Russia, do you?

There was one thing that told me volumes about the technical differences between these countries. At Expo 86, a "transportation" theme fair we held here in Vancouver, the Soviets [at that time] sent a spacecraft for exhibit. Looking at the command station, there was a fine, hand-tooled cowhide document pouch holding a large TIN [!] of Estonian bacon, a big hunk of dense black bread [floating zero-gravity CRUMBS], and a GLASS bottle of vodka. Their Soyuz [?] boosters deliver a higher payload than the American Apollos - and their use to launch tins and bottle while the Americans made powdered tang and the tiny calculator tells me that they can use brute force to get things done whereas a quiet submarine propulsion system is a matter of finesse.

Haha! You're the man!
I'll pass your knowledge to our prime minister. Brute force sometimes gets it done actually and the soviet jets combined brute force with utter beauty.

Sometimes when I read you comments (I admit I read most of yours and a couple of others) my Dr House alert starts blinking. Are you actually the architectural, slightly nicer version of Dr House? That said I think your comments are really funny and informative!

A Dwight-book for ArtLantis in the same style as your Lightworks would probably be a success!? I've got Abvents ArtLantis book but it's a feature based book which is pretty useless most of the time.

Nice modeling tips for the blades btw.

Re: how would you model this blade ?

Dwight — Fri, 07 Mar 2008 08:43:19 GMT

I love "House" because he is outwardly being true to himself while protecting himself from emotional pain. But he hurts people and this is what makes him so interesting. It is clear that when he has conflict with others, he does NOT ask himself "What would Jesus do?" before replying. Good thing he has smart and loving colleagues: especially sister Cuddy and brother Wilson in his TV "family."

He is the epitome of the phrase "does not suffer fools gladly." In my work on Archicad Talk, it is sometimes hard not to tease someone when the answer in front of them would take less time to obtain than writing to the forum. Like not knowing your computer has a search function, for instance. So helping people here has been my way to de-House [de-louse] myself.

I'm glad that you find me funny. I live an absurd life down here in the basement in my underwear - you are my coffee break buddies. I take a lot of coffee breaks.

Re: how would you model this blade ?

Djordje — Sun, 09 Mar 2008 16:55:42 GMT

Dwight wrote:
Depends who is listening.
///
they can use brute force to get things done whereas a quiet submarine propulsion system is a matter of finesse.

Reminds me of a story ...

US spent millions researching a ballpoint pen that writes in zero gravity. Russians used lead pencils.

If you don't have means, you have to think. See Archicad.