Hello-

It seems as if I have had many different recommendations for prop sizes on my Tower 46 engine. I was using a 10x8 that came with the RTF plane and engine, but I was recently told at a local LHS to use an 11x6. I also have checked the manufacturer's recommendations, but they are all over the board. Is there a prop size that works better for 46 sized engines?

Bjfrankl

BJ,
I am running an O.S. .46 LA in my Sig LT-25 with an 11x6 prop. Take offs are quick and and there is plenty of power for bailing a guy out of trouble. Ihope that helps.

Hi!
It all depends on what plane you have got!
A low winged sport plane a 11x6 (APC or RAM) is the prefered prop.
In a large slow flying high winged plane like a CUB a 12x4 is better.
For a Q-500 racer (Weight 1,6-1,8kg and 130 cm in span) a 9x7 APC prop is the way to go!

Tower sent me 11x7 for my trainer 60  when what I needed was 13 x 5   (OS LA65 engine)

Basically the engine will turn a variety of different props. Which one to choose depends on the particular application and how you want the plane to fly. Larger diameter props with a low pitch give the plane more pulling power but less top speed, sort of like low gear in a car. Small diameter, higher pitch props give less pulling power but higher top speeds. Those are just general rules of course, you'll always find one that seems like the exception.

Props of different designs and from different manufacturers will perform differently as well even if they are the same diameter and pitch.

The 11x6 that was recommended to you is probably a good all around prop for your engine and general sport flying.

The bottom line though is to collect a few props appropriate for the engine and fly them all then choose the one you like best.<br type="_moz" />

the tower like to rev a little, put a 11x5 or 10x7 on it and it really moves

It's not a Tower, it's an LA 65.

I gota agree 11x6 was a bit too much my motor. I liked the 11x5 best the 10x7 ran good but didn't let the plane slow down for landing.

Pretty much related to this thread I started this thread

http://www.rcuniverse.com/forum/m_9707771/tm.htm

I'm still stuck in between 11X6 and 10X7 APC props for my Evolution .45 Engine on P51 Mustang PTS. 10X7 is my LHS owner recommended, and I was doing good with 11X6, and due to weather condition, and my moving partially to new house, plus my new job I have not yet tried my Mustang with 10X7, but my personal choice is 11X6 and Im gonna try 10X7 hopefully this weekend if weather does not deceive[:@]

Mody

Post number 1 is asking about a Tower 46.

Prop selection and preference is a personal thing and what seems great to me may seem terrible to you.

If you want to experiment, that's fine and it can be fun. But, if you're happy with the performance of your current combination, there is no "need" to change anything.

The 10x8 and 11x6 will put a similar load on the engine. You'll probably get slightly less RPM with the 11x6 but should gain some static thrust.

What this truly means will only be known when you fly the plane and see which one YOU like better.

Most 10 and 11 inch props cost under 4 dollars so the cash required to do some testing is not huge.

See this link:

http://www.top-flite.com/accys/topq5000a.html

Thanks for all of the responses everyone! I went from using a 10x8 to using a 11x6 on my Tower 46 and have noticed a difference. My engine seems to have more power with the 11x6 but not as much top-end speed. The graph on the previous thread was very helpful since it allowed me to see the range recommended for my size of engine.

Bjfrankl

That really is a good chart and most engines will come with a list of props that fit in there operating range. Testing is the only way you will ever really know what prop on what engine plane combo YOU the pilot likes. One of my club web sites has a chart showing what the tested torque is on different engines using different props was. We have a torque meter we hook up planes to to see what kind of torque different props produce. It's just a static tester but it is fun just seeing how different makes of props will pull better. The chart isn't complete showing all brands and sizes of engines and props but it is an eye opener.