Hi to all.
I would like to ask you some questions on props, as my uni project is about testing an existing one and try to design a more efficient.
My first question is, which brand you think is the most efficient one, in terms of performance...from the mass produced props, like APC, Master Airscrew etc. I mean from your experience which prop you think gives more thrust and performs better through the speed range.

Second question is, do you think the scimitar shapes have any substantial difference. According to some prop manufacturers, they dont and they claim that the only advantage is a small reduction in noise (but really small). So what do you think on that...which ones do you generally use?

My last question is about the aerofoils that are used. I made a mould of a Master Aircrew prop and it seems to me like they use a Clark Y aerofoil...although havent still enlarge it, to confirm that. To your knowledge what aerofoils are used on model propellers generally?

Any help would be appreciated.
Thanks

In order,

1. APC

2. I agree, only a small noise reduction.

3. Most will be a Clark Y, or a slightly modified Clark Y.

Jetts

Thanks for your answer.
So I ll use the APC as a benchmark.

Do you know any site (or any published reports) where i can find low reynolds number aerofoils and their polars. I ve found various sites having aerofoils, mostly designed by professors that want some fame , but in order to get the data from testing you have to pay. So are they any lift and drag data on the net for aerofoils designed for 30,000 to 200,000 Re?

Anyway, thanks again for your answer. Hopefully tommorow i will scan the mould (from the Master Airscrew) and confirm if they use the Clark Y.

Try these sites for polars and co-ordinates:

http://www.nasg.com/afdb/list-polar-e.phtml

http://www.aae.uiuc.edu/m-selig/ads/coord_database.html

-Q.

thanks.
I ll go to check it.

Here's some reading that you might find useful:

http://www.mh-aerotools.de/airfoils/index.htm

http://www.supercoolprops.eftel.com/articles.htm

http://www.geocities.com/AMA271/Aeronotes/pwscol.htm

Good luck!

thanks a lot for that.
Sorry for being late to reply but apparently XP decided to suicide and left me .

Very interesting site (that i havent found before) is the supercool props.

Thanks again...until i have further questions