Cad

Well if I could get my hands on Windows 7 Pro and install it on the other puter and give it back to whom ever helped out there would be greatly appreciated!

Doc
 
I learned AutoCAD back in college in '93. It was a bit on the expensive side for just my home use. But I found TurboCAD. Very similar, pretty powerful and under $100. You can export/import to about any popular cad format. I still only work 2D but there is 3D in the package. Just I don't bother with it.
 
I have been using a program called Fastcad for about fifteen years. It has a 2D and 3D version and is easy to learn. Being old school I like being able to enter dimensions from the keyboard. I have Alibre as well, purchased it last August. I am still trying to learn Alibre, purchased the tutorial and direct help, but it is slow. The help system is poorly written, and direct support, expensive is slow to respond. I know, once you learn it it is great but be prepared to take a lot of time.

Check out Fastcad @ [h=3]About FastCAD v7[/h]


www.fastcad.com/infofc7.php
 
I use draftsight for all my 2D drawings. Havent really played with 3D yet. I run a waterjet for work and they use IGEMS cad/cam. Draftsight is 100% free. And works great.
 
With the advent of cow cost 3D printers, I decided I needed to learn a solid modeling program. I have Alibre. The two things I would make are propellers and two stroke cylinders. Both are very complex shapes and my last attempt at machining propellers using CAD and CAM was a failure. However, I've been able to model some of the important characteristics of a surface piercing propeller with Alibre. Below are three examples. So far a method to draw the transfer passages of a high performance two stroke have been unsuccessful. These programs are far from intuitive foe complex shapes. The last two pictures show whgat is needed. I've tried various lofts, cuts, and revolves. Any suggestions?

Lohring MillerPropeller 72 x 100 with cup.jpgPropeller 72 x 100 - 20 rake - 50% progression.jpgPropeller 72 x 100 - 20 rake.jpgAp125-01.jpgAprillia 125 transfers.jpg

Ap125-01.jpg Aprillia 125 transfers.jpg Propeller 72 x 100 - 20 rake - 50% progression.jpg Propeller 72 x 100 - 20 rake.jpg Propeller 72 x 100 with cup.jpg
 
I'm no help on the engine core problem. I am working on prop designs for model Z drives. How did you generate your props. I am generating a helix at the diameter and pitch I want and then using that as a pattern to make sketches for a loft. I also use Alibre. Here is a 5 blade prop that will go into a 74mm Kort nozzle.

Dave

prop74mmsqew_zps23ef29f4.jpg
 
I have no experience with shrouded propellers. Surface piercing props have several characteristics that need modeled:

1. Helical pitch - no successful racing propellers have straight helical pitch
2. Pitch progression - many props have a gradual increase in pitch from the leading edge to the trailing edge
3. Cup - most successful props have trailing edge cup, a sharp increase in pitch at the trailing edge
4. Rake - the newer propeller designs have the blades raked to direct the thrust cone more to the rear
5. Edge cup - many racers curl the outside edge of the propeller to help contain the water flow
6. Projected blade shape

I model the prop blade as two helices traveling in different directions from the same cross section. You need to create two planes, each with the same cross section, at the same place; one for each helix. The cross section controls blade thickness, cross section shape, rake, and edge cup. Progressive pitch is controlled by the variable ratio of the forward helix. Cup is also controlled the same way on the rearward helix. I start the helix with the same pitch both directions then change the ratio. As an example, if the ratio forward is .5, the pitch at the end of the revolved blade will be 1/2 the start pitch. If the ratio to the rear is 3, the end of the cupped section will be 3 times the start pitch. The projected blade shape is determined with the extrude cut command along the shaft axis.

Lohring Miller
 
Hi Guys,

Autodesk Inventor Pro (student edition), has all the bells and whistles---just prints a text border on all your drawings stating that it is from a student version, is available for free as a download from Autodesk's website. I personally downloaded version 10 and have to admit it is almost as good as SolidWorks for 3D models and drawings. There are also a lot of free models available for SolidWorks and Inventor Pro from a website called GrabCad.

Hope this helps a few.....
Regards,
Norman
 
I worked in Auto Cad for 15 years of so while I worked, and I continue to use it in retirement. As other have mentioned, I too picked up a student license very cheap for my own use.

I found Auto Cad is able to handle many needs of large organizations which smaller scale users might not have. I moved from product design to product testing to regulatory compliance (it's a dirty job, but somebody needs to do it). The design guys moved toward other software, but I was forced to stay with Auto Cad because the whole regulatory structure had settled on it as their common tongue, and it interfaced with a lot of other software. I had thousands of "drawings" from dozens of suppliers that were passed on to engineering consultants and certification agencies with chain of custody assurances. They accepted Auto Cad.

If you are focused on CAD/CAM just to make better parts, that aspect of Auto Cad, which I suspect is a substantial contributor to its price, might not be valuable to you. If you have to submit finite element analysis of deflection under load or heat flow to a PE for validation before you can sell you products, you'll find Auto Cad is universally accepted.
 
So how much does Alibre cost if a guy was going to buy a full-up version?



I like Alibre. -a lot. In the past several years, I tried at least a half-dozen of the big name CAD programs. I'd spend 4-5 days doing the tutorials and interactively using the program -And I got nowhere. This was with the full-demo versions of SolidWorks, AutoCad, Pro-E etc. Also purchased AutoCad thinking it must be fairly easy to use. Nope... BTW: I'm an electrical engineer in real life so, complex programs are nothing new to me.

I tried the demo version of Alibre, watched 45 minutes of online tutorial videos and two hours later was making simple parts. Liked it so much, I got the professional version. Here's something I made tonight in a couple hours. I've only had the program a couple weeks -but admit burning the midnight oil, mainly because it's fun and addictive. This is the first CAD program that ever struck me so well.


BTW: If you click the PDF image, you can use the mouse buttons and scroll button to move and 3D rotate the image. Some of the clone versions of PDF readers don't handle it too well though. Use Acrobat Reader.

Ray
 
Back
Top