I know that an airfoil located toward the leading edge produces better lift, but is better suited to mono-directional applications such as fixed pitch where there is usually no inverted lift needed. A bi-directional airfoil is closer to center and reacts better upright or inverted. It's like the difference between the wing cross-sections of a passenger jet and a fighter or aerobatic jet. (same differences in wing loading and whether or not inversion is anticipated.) One would have to apply more negative collective during inversion with a mono-directional blade compared to normal upright flight in order to make up for the difference in directional lift characteristics.

 

http://www.grc.nasa.gov/WWW/K-12/airplane/geom.html

 

Stability and maneuverability have more to do with weight and/or rotating mass. A heavier blade or even longer blades will have more rotating mass, especially at higher head speeds and will have more of a "flywheel" effect and be more stable and less likely to buffet at high forward speeds, but response will be slower thus affecting overall maneuverability. a lighter weight blade or a shorter blade will have quicker response due to less rotating mass and less of the flywheel effect, but will be more unstable at high forward speeds. There is a happy medium somewhere in balancing length, surface area, head speed, and weight. A long blade will usually have a narrow cross-section, and a shorter blade will have a wider cross-section. Example: I use two sets of blades on my 120sr: stock blades have more surface area, especially toward the grip where velocity of blade is slower,and they have a more aggressive airfoil. They are light weight and are fairly responsive even considering they are on a FP heli with a mixing fly bar. I use the stock blades when flying outside or in larger indoor areas. On the other hand, I use a set of 200srx blades that are shortened to 1/4 inch (6mm) shorter than stock, pitch was increased about +4 degrees to increase lift just a bit, they are a bit heavier, and have less surface area, which produces higher head speed, higher stability due to more rotating mass (more flywheel effect), but make the heli respond slower. I use the modified 200srx blades primarily for flying indoors in smaller areas where more stability is beneficial.

 

By the way, I'm no aeronautical engineer, so if I'm wrong about anything, feel free to correct me.

 

Check this vid out from Tim Jones the designer of Cyclone Blades.

Probably the first video ive seen of any manufacturer on why they designed they're blades a certain way.

Watch till the end and you'll get to see his famous Beast getting is ass smacked.

Cyclone Rotor Blades - Tapered Airfoil Technology:

 

Oh nice work Tim.
I have never tried them, has anyone had a go with them?

 

I know Quang loves them he's offered a couple of times to try them id feel slack if I decked them I might have to harden up and give them a crack

 

Thanks @Beaver and @feral.. Im going to read these really closely - i think there is alot of truth in what you say @Beaver . Thats some good material...

 

Nice video "feral"

 

Nice!

 

I have really been enjoying rails (715's) due to their wide code and awesome FF light characteristics. There is certainly a compromise between a blade that is suited for both FBL or FB helicopter set ups. I am yet to fly a blade with both styles considered. I have never tried Cyclones, their design is nothing like anything else so it would be interesting if they cater for all things relative?

 

I like the concept behind those Cyclone blades. They seem like a perfect mix of the two sets of blades I use on my 120sr I posted earlier in this thread. We need more innovative thinking like that.

 

I liked flybar blades on my old trex 500 dfc turned it into a squirrel on crack

 

I'm running Cyclone main blades on my Rush 700. They are much quieter than the blades that they replaced. IMO noise=innefficeincy.

 

Based on what I've read, they cater to 500 series and up. That being the case, I will have to modify another set of 200srx blades to Cyclone specs for my 120sr, and I'm s.o.l. for my Nano.

 

Or just buy a 550 class heli... ;-)

 

Easier said than done. I don't have $1000 to spend on a "high end" heli right at the moment...... till then, I'll have my fun experimenting and modding what I have at minimal expense.

 

Trex 550 awesome heli... Regret selling mine.. You should pick up a second hand one for 500 with spares