#### alfredo montalvo

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I am interested in Jan Carlsson's JC Propeller Design software too.

Regards

Regards

- Thread starter FokkerDVII
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I am interested in Jan Carlsson's JC Propeller Design software too.

Regards

Regards

I’m working on a functional replacementI am interested in Jan Carlsson's JC Propeller Design software too.

Any progress?

If you want me to kick-off the process, let me know and I will start with how I did it.

George

How does the program handle different airfoils and blade tapers.

Remember this is just his basic program, I was going to apply Paul Lipps approach of Elliptical Lift distribution for the Chord Lengths and also look to Jack Norris's approach to compare - but all that is a long slow process. It took me a week of spare time to get this far - like others I had been putting this research off for some considerable time. I had two copies on different computers and when one was corrupted I figured it was about time to understand the basic processes.

JC doesn't use modern airfoils, he used a combination of Clark Y and RAF 4, he did offer up that information. From research, others consider that using Laminar Flow Airfoils to be a waste of time, probably considering bugs and damage to the leading edge.

It is a very interesting exercise and an education in itself for those interested in the how and why. My experience is that most people just want something off the shelf, or professionally made. The local Prop maker (now retired), made a beautiful wooden prop, with an indestructible leading edge and brilliantly copied proven propeller designs, but had absolutely no idea of how to calculate and design one.

Personally I think everyone should know the basics, so I will offer up as much as I lean, when it's available - to those who are interested.

George.

I believe Hercules props used his program.

George

That is correct. I spoke with Rupert Wasey of Hercules Propellers some years ago and can confirm.

There's no magic in Carlson's program; he just never told us what book he used to derive his method, but he did not hide the fact that it was a method he found in a book. So a survey of the literature might help instead of trying to reverse engineer it. (P.S. It's RAF-6, not RAF-4.)

Remember this is just his basic program, I was going to apply Paul Lipps approach of Elliptical Lift distribution for the Chord Lengths and also look to Jack Norris's approach to compare - but all that is a long slow process. It took me a week of spare time to get this far - like others I had been putting this research off for some considerable time. I had two copies on different computers and when one was corrupted I figured it was about time to understand the basic processes.

JC doesn't use modern airfoils, he used a combination of Clark Y and RAF 4, he did offer up that information. From research, others consider that using Laminar Flow Airfoils to be a waste of time, probably considering bugs and damage to the leading edge.

It is a very interesting exercise and an education in itself for those interested in the how and why. My experience is that most people just want something off the shelf, or professionally made. The local Prop maker (now retired), made a beautiful wooden prop, with an indestructible leading edge and brilliantly copied proven propeller designs, but had absolutely no idea of how to calculate and design one.

Personally I think everyone should know the basics, so I will offer up as much as I lean, when it's available - to those who are interested.

George.

Let me save you much effort and time:

Instead of trying to reinvent Lipps' work or wade through Norris' swamp of language, just read the papers written by Adkins & Liebeck and by Larrabee, posted as references 10 and 11 on Martin Hepperle's JavaProp bibliography page (Bibliography) and start coding (or just use JavaProp, but you'll have to fudge the transition to the hub, an important detail that JavaProp inconveniently ignores). If you write your own code using this method you will obtain a skeleton into which you can plug Lipps' elliptical load distribution (if you must ) or onto which you can impose Norris' canoe-waterline blade planform ( ) but in any case you'll be well on your way to duplicating the most successful propeller design computer algorithm of the 20th century.

Otherwise, get Fred Weick's 1960(?) Sport Aviation article in which he expands on his N.A.C.A. Technical Note 212 from 1925. It's as good as any thing else, especially when you consider the state of the art as exemplified by your "local prop maker." You can get the important design information for a good prop in about 20 minutes this way.

If you have the stomach for Theodorsen's method, find the 2004 paper by Quentin Wald and the four NACA reports (924 et. seq.?) that tell

Another reference, ANC-9, has a different design approach and also contains lots of good info, but you also must absolutely have the huge errata supplement before trying to use it to design a propeller.

Finally, Henry Borst and Associates did a series of NACA reports (10 parts) in the 1960s(?) that are available from NASA's technical report server and will help you design everything right up to and including your own personal homebuilt V-22 Osprey if you have a spare weekend or two, but it might be overkill.

For ordinary airplanes on ordinary days, Weick's method will get you to a serviceable product faster than anything else. Unless you already have a computer program....

For those awaiting my "functional replacement" of Carlson's JCPropellerDesignX please standby and continue sending me copious amounts of money and caffeine. Thank you.

Sorry, no money but I've got popcorn at the ready!your own personal homebuilt V-22 Osprey

I'm sure I did a spread sheet on Welch, but can't now find that book, it was fairly involved and in the end I wasn't quite sure of what I had. The beauty of Carlson's program it confirms the figures of my own work- apart from the slight difference in angles. However when I reversed the maths for my angles, the Pitch was accurate, and I used all 9 decimal places to assure accuracy. That's why I know he did some modification on the angles.

George

Might some of Carlsons be from empirecal?

George

JC's calculations the Angle (B) at 15% is 48.42 - My answer was 48.41832095, one would initially think a simple rounding-up of the number. I did.

However at 100%, my angle (B) is 25.01533069 where JC's is 23.83 - more than 1° difference, down.

George

George, are you working from the same reference sources as he was? Can you be more specific about where this discrepancy is showing up?JC's calculations the Angle (B) at 15% is 48.42 - My answer was 48.41832095, one would initially think a simple rounding-up of the number. I did.

However at 100%, my angle (B) is 25.01533069 where JC's is 23.83 - more than 1° difference, down.

George

Jay Lempf, really unsure at this point in time - still looking, but appreciate the suggestion.

George