Trying to make a propeller

[cpascual]

Hello everyone,

I am a new user of AutoCAD. I have used other CAD programs like Pro/Engineer, but I am now currently using AutoCAD 2010. I am trying to model a 3-blade marine stlye propeller, but I am kind of stuck right now. I have attached an image of where I am right now in the process, but I am not sure if I am heading in the right direction or if I am going to hit a dead end soon. I have just created a hub and completed the starting point for the propeller blades using EDGESURF. From what I heard online it is somewhat difficult to model a marine style propeller, so any help or advice would be awesome. The propeller has a 12" diameter and an 18 degree pitch angle. If anyone can give me some direction I would be very grateful. Thank you.

 

[kencaz]

This is not precise or even dimensioned but will maybe give you some direction. I used a series of ellipses for the loft profiles and rotated them at progressive angles, (you can add more or less depending on the smoothness you want).

 

Then use a spline to connect the loft profiles and loft using the splines as guides. Spend some time creating the profiles and you can get some good results.

 

Oh! don't do three blades... I only did a single blade and just did a polar array.

 

I believe in 2011 it would be much easier since you can twist and manipulate surfaces better, but I don't have that version to try it.

 

 

 

Good Luck

 

KC

[JD Mather]

I would not use commands like edgesurf. There are better ways in AutoCAD 2007 and later. In fact, I would do this part about the same in AutoCAD, Pro/E, Inventor or SolidWorks.

I think I posted a marine prop in the Inventor forum here a while back.

[cpascual]

This is not precise or even dimensioned but will maybe give you some direction. I used a series of ellipses for the loft profiles and rotated them at progressive angles, (you can add more or less depending on the smoothness you want).

 

Then use a spline to connect the loft profiles and loft using the splines as guides. Spend some time creating the profiles and you can get some good results.

 

Oh! don't do three blades... I only did a single blade and just did a polar array.

 

I believe in 2011 it would be much easier since you can twist and manipulate surfaces better, but I don't have that version to try it.

 

 

Hey KC I got a quick question for you. Can a part of a loft profile be made with a 3D polyine? I see that you only used 2D ellipses, but I just want to see if at least one of the profiles can be done 3 dimensionally, or if that would mess up the command. Let me know when you get the chance. Thanks for your help.

[kencaz]

Hey KC I got a quick question for you. Can a part of a loft profile be made with a 3D polyine? I see that you only used 2D ellipses, but I just want to see if at least one of the profiles can be done 3 dimensionally, or if that would mess up the command. Let me know when you get the chance. Thanks for your help.

 

Well, Yes, but it depends. Autocad can be picky sometimes about lofting especially 3d lines. Try it and see if you get an error.

 

Here is another method that is actually easier and I prefer. In short I created a flat profile of the blade (easier), then created a surface that could be thickened to a solid for slicing. I used only two lines for the loft, (one rotated). I then created the [guides] using splines. These can be easily manipulated to get the curve you want. loft the surface and slice the solid twice to get the thickness you want. Now just fillet the edges.

 

 

 

 

KC

[cpascual]

I haven't gotten to this point yet, but do you mind telling me how it is that you could mate the prop blade to the hub and how it wrapped around it? I just don't want to get stuck later on and I should get to that point sometime later today. Thanks again for all your help.

[cpascual]

I am having a terrible time right now trying to make the guide splines. I am just not able to get the hang of it. You say that splines can be, "easily manipulated to get the curve you want." But I still have been unable to figure them out. If you have any suggestions to using splines or making those curves I am all ears.

[cpascual]

I think I may be able to do it with just 2 straight lines on the ends as guides but you can still let me know how to work with the splines if you get the chance.