Prop
 

What size prop for a 45 Super Tigre motor. I have been using a 10/6 on a Great Planes Cherokee kit plane. Would a 11/??? be better?

The best way to find out is the put one on and test. Just be sure you still have ground clearance before you taxi it to the runway

I would suggest an APC 11 x 5 as a starting point.

11x6 is perfect

Hi!
If you fly at sea level an 11x6 prop is the best size for most sportplanes with a .45 engine, but...prop brand is equally important!
Best props on the market performance vise is Graupner G-Sonic, APC, and RAM!

And that, in a nutshell, is why I said to take the props being considered and test Test TEST!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
There is no way to really know what a prop will do until you fly with it several times and chart the results

What do you want to change about the flying characteristics? If you want better acceleration or more vertical performance, go with a bigger diameter prop with less pitch. If you want more speed, go smaller with more pitch. Going bigger and keeping the same pitch will slow the plane, make it quieter, and reduce the power output and fuel consumption of your engine. So what do you like or not like about the 10x6 that makes you want to try something different?

The 10/6 works very well. I was just wondering if anyone had any ideas about other props.I will try the 11/6 and a 11/7 just to note the difference. Sometimes to try something does result in a difference that is more to my liking.

Hi!
You can ofcourse use a any prop, including a 10x6 on a .45 engine. On a Q-500 type of plane with a span of 130cm a 10x6 is better but on a 140cm span Cheeroke a 11x6 is the prefered size.

I tried the 11/6 today and it did reduce the power output. The plane was not as responsive from 1/2 throttle to full and at 1/2 throttle it flew slower with a tail down attitude. On the second flight I went back to a 10/6 and the ST 45 opened up with more power and quicker from 1/2 to full throttle. I will stick with the 10/6 .Thanks for your comments. Testing did help but your input was interesting.

Hi!
What prop brand did you use? Did you adjust the needle?

I adjusted the needle with the 11/6. It was a wooden prop. The 10/6 change caused a needle change also and it was a Master Airscrew prop. The 11/6 just seemed to lag with power from 1/2 throttle to full. The 10/6 just worked better for me.

Not all props are created equal. You might try an APC prop in the same size, or maybe even a size up... I would honestly first try a 10x6 APC and see if that makes a diff. They're far stiffer then the Master Airscrews, and perform much better in my experience. An APC should rip pretty good compared to the Master.

APC makes a 10.5x6 that I like on an OS 46 AX; about 500 rpm less than the APC 10x6 with a little more diameter.

Apc
 

I have used APC props and they do well. I think they break easier and the color doesn't appeal to me.I have painted them flat black with yellow tips and they look good but still break easier than MAS.I have everything packed for my move and it will be several weeks til I fly again but I will try the APC again. Thanks for your input. I enjoy getting a discussion going on this forum.

Yes... an APC prop breaks easier then a MAS... that's a fact. A MAS prop will scuff/scratch/wear in many cases from a prop-strike.., where an APC will chip and/or just break from a simple prop strike... and I do always advise if an APC prop comes into any contact with the ground, toss it. They do also fracture and splinter.. and it can be undetectable until it explodes... I'm not knocking APC... I use them more then any other prop for small engines.. probably every plane.

It's up to you if you want more durability, or better performance. There's a point where you won't be as much concerned about the durability, and you'll want more performance.

When you get to the point that you're not breaking any props(regardless of brand)... then put the APC on it. Some of us haven't broken a prop in years... I usually break one maybe once every year or 2, not on the same planes though... I like to rotate my breakages.. :D. I have went years at times though with no problem... I do have a few planes that have the originally installed prop from well over 10yrs ago... Really it's a matter of just experience and learning.... just grease the landings as best you can... try to focus and concentrate.. don't carry on conversations when your flying or landing.. stuff like that... you can do it.
Good luck.

Hello everybody, I think the OP got some good answers and info now on a bit of a different side....I have said engine in a biplane and would like to "tone " it down. I am using an Xoar 11x6
now as I have a few for the other planes which are 4 cycles. But the ST45 is over powered to me and would like hopefully experienced help on the use of say a 12x4-5 prop on it. It's my Sportster
in my gallery if you need pic's I just found a prop at my local HS they are holding it .

Why not just pull back a little on the throttle stick.

Thats what I've been doing. Don't get me wrong I just want it toned down alittle right now it seems like flying at just above idle to cruise.
At 3/4 its crazy fast and then if ya go full.....hoopdy tear the wings off. I'm think 12" to keep rpm's right and pitch to keep some verticle.

I had an old BUSA Phaeton biplane with an Enya 45SS. I put a 12x4 prop on it and loved it that way. Slows down better on the back side of a loop, and it lands easy because it slows down better. Keep up a bit of throttle till you're close to the ground, then cut the throttle and it drops right in for a three point. Speed level was still way more than I needed. I think you've got the right idea. Jim

buzzard we is cut from the same...I like it. Only prop manuf that seems to make a 4" is Xoar and hard to find....but my local is holding the last one of theirs for ME !!
I really just need to try'em

Mike, APC and MA also make them...https://www.towerhobbies.com/cgi-bin...?FVSEARCH=12x4

Good luck!
Jim

Thanks buzzard, I try to stay away from the composites, although I've had good luck with the glass MA's

Hi!
MA props are the worst props there are! Both sound wise and performing wise.
Best props are Graupner G-Sonic, RAM and APC.

Just so ya know, I don't have any real experience with glass props had
one MA and it got the plane in the air...I fly wood exclusively.