Hey Guys..........

Need help with propellers! Whats up with the numbers? 10X5 11X7 etc....

I have a OS 46FX and they suggest 9X7, 10X7, 11X6

I assume its length X pitch........

So any help on the characteristics of these propeller sizes would help!

Thanks
Richard

Hi,

I'm new to this so not much help.. But you may find some answers
here:

http://www.bolly.com.au/book/Book.js...er=2&Section=2

And I'm sure others with jump in soon with help..

Lots of posts on this subject so I'll be brief. First number is prop diameter in inches. Second number is pitch, the (theoretical) number of inches a prop will pull itself foward per revolution

Andy

I flew a SPAD Deb alot with a 46FX using a 10x6 and 11x5 APC props. For trainer type planes you want to keep the speed down so you don't more than a pitch of 6.

You match the pitch and diameter to the engine, fuel and desired flying style.

A typical .46 runs well using the 10X7 to 12X4 with 10% to 20% nitro fuel. The 9X7 is a bit light load for a .46 even on low nitro fuel. in the range of the .40 size engines, you trade one inch of dia for one inch of pitch to keep close to the same load on the engine.

Trainers as mentioned don't need speed. Beginners typically need power for takeoff and you get more power at low airspeed with larger diameter and lower pitch. the low pitch also helps with slowing the aircraft down to land.

Most ".40 size to .60 size" trainers (the "60 size will typically say .40 to .60 engines are recommended and they fly fine as trainers with a .46.) the 11X5 is a good choice for the .46 engine You can use a 11X6 with a more powerful .46 such as the O.S. FX series. (The LA will not turn a an 11X6 nearly as well). If using a .40 on a .40 size trainer (almost no one does it any more... but a .40 size trainer flys fine with a .40 or even a .25...) you would want an 11X4 if its a low power engine... and 11X5 if its a good ball bearing one.

These are STARTING recommendations... different flying styles will make different props seem better, because they will give you different performance.

Thanks for the help guys.................

Lenth of Propeller X Pitch (distance of travel)
Since the OS FX .46 is on a trainer, kinda a slow i will going with a larger prop.

10x7 or 11x6.

Thanks for the advice!

I would suggest 10X6 or 11X4.


Andy

FH as usual is right on the nose. I just want to add a few. Diameter=pulling power More uummph the ability to get in the air quicker, pull out quicker. Pitch=speed, How fast will the plane go. Usually as FH states you want big diameter, low pitch on a trainer.

Mark Shuman