Prop Designer blog

For those who don’t know, an ornithoper is an aircraft that uses an animal-like way to fly, usually flapping wings.

The University of Onterio is building a human powered ornithopter to fly the classic figure of eight Kremer prize course to prove the concept. The ornithopter is based on work on a powered ornithopter that flew once and then they had to add a jet engine. The flight lasted 14 seconds and was terminated due to lack of control.

I don’t have high hopes for it ever taking off under it’s own power but… what do I know?

I noticed the site had a visit from www.army.mil . Does this mean the US. army is interested in human powered flight? I am told that the army has some software that searches the web much like Google but it is looking for terrorist materials and links with Al-Qaeda. I think they will have to work hard to create non-existent links between what I do and any terror organization.

I occasionally tweek all or part of the web site to improve them, at least I hope they are improvements. I have added links to news, this blog and the forum to the library part of the site. The gallery needs similar links adding and I will have to ask if Chris Roper would also like the links added to his book at http://humanpoweredflying.propdesigner.co.uk/.

A full redesign of the site would take some time and is not something I feel like doing just yet.

I am thinking of adding features to Prop Designer. A possible improvement that is reasonably easy to add would be a bit on bending moment along the blade. It is up to the user to use this information to work out the strength of the blade.

I was also thinking of adding the option of entering an existing blade design and seeing how good it is. At the moment Prop Designer initially calculates the blade angle based on blade element and momentum theory.

I don’t know what features people want so I normally add the features I want.

One of the most popular searches on my web site is for the NACA 0012 and some coordinates for it. I also have the NACA 0009 section, the NACA 0021 section as well as a number of others on the site.

Pushing my mathematical powers to the limit I noticed that the thickness of these sections were divisible by 3 and I wondered why this was. The answer dates back to the 1940’s and 50’s. Aerofoil section data was hard to get and without computers or access to wind tunnels designing your own was generally not an option so you had to find a source of data. The easiest and most common source was “Theory of wing sections” with a subtitle of “ including a summary of airfoil data” by Ira H. Abbott and Albert E. Von Doenhoff. The appendicies provide a lot of data on NACA aerofoils and they are of various thicknesses all divisible by 3! This was often the source for early HPA designers

With computers it is possible to design your own aerofoil section or even take a NACA section and change it’s thickness to 10, 11 or even 11.5% thickness if you think it is appropriate.

I was thinking about where the early HPAs flew and I realised while Lasham is doing well, Hatfield, where the Puffins flew is now part of campus of Hertfordshire University and Radlett, where Toucan flew, is now a housing estate.

While HPAs require hard surfaces to take off on they don’t have to be runways desiged for passenger jets but other sutable areas like private roads that have the clearance for a HPAs wingspan are not easy to come by.

What’s stopping you building a human powered aircraft? If you want to build one it is easier than ever, especially when compared to the pioneers in the 1960’s. New materials like Carbon fibre have come along, new aerofoils like the DAE series and computers to help the design. There is, of course, the nearly 50 years of previous HPAs for inspiration so there is very little reason not to start a design.

There are, however, the same old problems of where to fly. Most people do not have a 1,000 metre runway nearby and even if they do getting permission is not going to be easy as runways are usually used by other planes that pay for the privilege of using the runway.

I was informed today there was a problem accessing the forum (Thanks Sky Captain) so I invertigated and found I had access problems with FireFox and Chrome. I ,of course, was using something different, Internet Explorer which had no problems. The link has been changed from a button with Javascript to just a link to click on and this seems to have solved the problem. Please let me know if this is not the case.

I hear about problems with opening DAT files but I don’t know how big a problem it is. I have written a small program that associates whatever program your system uses to open TXT files with DAT files. If anybody wants such a program I may add it to the library site or I could add a set of instructions for changing the file association. I know sometimes other programs use the DAT file extension for their own use so opening a DAT file can either show rubbish or at least text that is not in the desired format.

There must be some more exiting or at least more relevant to human powered flight to write about!

I have just uploaded the links to this blog and the forum so now I just sit back and wait for something to happen. Well… I try not to and I will be working on more content for the site. The succes of this blog and forum depend son how much you read this blog and how much you use the forum. Don’t blame other people if very little happens, add your own comments to the blog and add your own entries to the forum.