Hello
I would like to model an rc airplane propeller with existing dimensions such as 8 x 4.
Is it possible and how because according to what I have seen elsewhere (heliciel), it would be necessary to create several profiles, as far as the length(8) is concerned, it is not a problem but for the step(4)???
diiity
Hello
To make your propeller, you can create the profile of the propeller on planes spaced a certain distance apart. Once you have all the profiles, you use the Boss/Smooth Base function to create the propeller.
Hello diiity
Exactly like Gauthik67 did who put each profile on a plan but who seems to me not to have used a guide curve.
To complete!
1°)The planes must not be equidistant since the pitch varies a lot towards the hub and less and less as it moves away from the hub (towards the tip of the propeller).
2°) Be careful because you need to use at least two guide lines because the dimensions vary in all dimensions. Two or more depending on the complexity of the propeller. I'm thinking of three with a central curve and two with one on the leading edge and one on the trailing edge) (check the vocabulary used leading edge??? for the propellers because here I used the one of the airplane wings)) In other words, as the width of the propeller also varies, your guide curves must be used to control the width.
Nothing is more difficult to make a theoretical profile except for specialists (hence the usefulness of heliciel) after smoothing with good sketches and good guide curves, so it's "finger in the nose" for Solidworks.
Thank you both for answering.
The problem is that I have to make a propeller with a known pitch in my example 4.
How do you reproduce it that I think corresponds to an angle?
diiity
Hello
We need to be given all the information because for the moment: apart from the fact that it is a propeller, we know nothing about its exact shape.
You give us the radius and the pitch but nothing about the constant angle, which is the angle formed between the horizontal plane and the wire of the coil.
But you follow your idea without apparently reading what we are proposing. To draw the propeller itself, you need to know the cross-sectional profile with, say, every centimeter along the length of 8 from the axis of the rotor to the end of the propeller.
Look here at the different sections of a propeller which shows well what I am trying to make you understand. If you can't establish the shape of what corresponds to a 90° cut from the vertical axis of the propeller. The vertical axis (blade axis) is defined by the center of the rotor axis and the tip of the propeller.
See the attached photo of M. A. Moirier (see the link at the end of the message) 
On this forum we can only tell you technically how to do it with SolidWorks but from the information that you have to provide to make the sketches of each plan yourself and that you will not get on this AMHA forum because it is not its vocation.
Kind regards
Hello
As I want to reproduce a known propeller, I would need to know the profile, which is generally constant, the chord of the profile, the number of sections as well as the angles given to each profile in each section.
It is these last 3 parameters that block me.
diiity
Hi @ diiirty
on your image posted
It is specified how to create the profiles
the number of sections
the location of these sections
you just have to create plans of each section
One sketch per shot
and a smoothing either volume or surface
I think that if you take the values of your scale
It must be possible to find the right formula
@+
Hello
I ended up finding some information on the net.
The number of sections is about 10 from the axis of the blade foot.
In model aeronautics, the profile is constant and therefore so are the gaps. An exception is at the foot of the blade where the profile is reinforced for the strength of the propeller. This is possible because the yield is negligible in this area.
Now the difficulty, for me, is to find the angle of inclination of each profile for a given step, in my case I would like to do an 8x4 so the step of 4. It is this calculation that I lack.
The image posted is just an example
diiity
And your image posted at what pace?
Hello Diiity,
Knowing that the pitch is constant, the angle of inclination of your profile will vary according to your diameter. In principle, propellers are characterized in inches. I guess in your case, it's an 8" x 4" pitch diameter. But whether you calculate in inches or in mm, it won't change anything. You will always have the same angular results.
For example, if you want to know the angle of inclination of the profile at the tip of the blade, you have to calculate as follows:
Alpha ° = atan (pitch / Pi* Diameter)
Which should give you about 9° in your case. You will have to redo this calculation as many times as you have profiles to generate your smoothing. The angle will increase as you get closer to the center.
I hope I was able to help you.
Steve
Hello Steve,
Great, it's progressing, I'm not a math person, can you confirm that atan is indeed tanh on the win7 calculator and if so that you have to first calculate what's in parenthesis and then press the tanh button
So I would have atan(4/3.14*8)
diiity
Hello gt22,
Sorry, I had skipped you, I don't know the step of this image.
diiity
NO!
Tanh is not Atan. to get atan on the W7 calculator, you have to do inv-tan.
tanh is the hyperbolic tangent.
Hi all
I had finally found the formula on the net, I am attaching the excel file.
On the other hand the last data I am missing is the rope and its variations, could you attach to me the SW file which corresponds to the capture you put in your excel file?
diiity
Hello Diiity,
This is a test done a few years ago. I tried to model a propeller for indoor flight models. In such a case, it is not subject to the same stresses as a propeller for external flight. The file I have created is therefore purely indicative. It cannot be applied to an external solution.
Regards.
Steve
Hello
Indeed, the profile is a bit peculiar and does not look anything like a usual profile.
Alternatively, the XYZ curve function allows you to draw a profile based on coordinates from a txt file. that I extracted from the SLDCRV file .
What surprises me in this file is that there are at the same time the coordinates that form the curve, the chord and the angle, the gap between each profile being the 3rd column Z, that I understood.
I attach the corresponding sldprt in the second message
diiity
Hello diiity,
Seeing the propeller modeled in your last post and its dimensions, I guess it's a file you got somewhere.
In any case, it's a very good example of achieving what you're trying to achieve. However, the "know-how" is found in the orientation and positioning of the different profiles. This implies that having the SolidWorks file won't really help you if your goal is to be able to modify the different parameters of your propeller. (especially the PAS)
On closer inspection, in the XYZ curve function, we refer to a script: propscript
If you search on the web, you will find the following information on GitHub: https://github.com/Nate711/propscript
It is likely that the profiles imported into your SolidWorks example come from this script.
Regards.
Steve
Hello
Yes indeed I got this file on the net.
I looked at the link and there is a file, apcsf_9x4.7_geom.txt, whose columns are similar to the first three of this one:
It's from the javaprop software whose site is here:
http://www.mh-aerotools.de/airfoils/javaprop.htm
But how do they integrate this script into the coordinate file and thus have the chord, the angle and the radius of each plane on SW, that's what it's all about because it's the case of each txt file imported with the XYZ curve??
diiity