What will the different sizes do? I've got an 11x7 on my OS46 for my sig senior. I've been told maybe to change to a 11x6 ... what will that do? what would it do to change to a 10x6?

I guess I just don't understand how the changes will effect the flight charactaristics. I know RPM's will go up with less bite, but what will that do in flight?

Thanks

Kevin

the numbers mean 11 inch and every revolution means 6/7 depending on the pitch 11/7 11/6 ect

Hi!
In due time you will find out how it all works...it's really easy.
A smaller prop will increase rpm, a bigger will load the engine more (that means more heat).
A 11x6 (preferably an APC is the one you should use ...or a 12x4 if you want to fly real slow)

In general, going to a lower pitch/higher diameter, you will see an increase in acceleration at the expense of top speed. Going to lower diameter/higher pitch, you will see an increase in top speed and decrease in acceleration. This is very much like the gearing in an automobile. With any given gear, you get a certain combination of speed and pulling power. The trick with props is to find the right compromise for your airframe and flying style. On that Kadet, you would probably be better served by the 11x6 than the 11x7 since you don't want/need lots of speed. You might want to also experiment with an 11x5 or 12x4. In the end, it all comes down to what you are looking for out of your plane.

Hope this helps.

That helps ... my instructor suggested a 11x6 for my next prop and we were flying at the time and I forgot to ask why.

So going from 11x7 to 11x6 is essentially a "lower gear"

accelerate better on take-off?
slower at idle speed for landings?
less top speed? (which I really get to with a trainer)

right?

Absolutely correct. It's like you downshifted.

Yes, but...

There are cases where going down in pitch at the same diameter can result in more airspeed.

The reason is that our engines are not linear devices. If the prop is too big, then the engine can't produce it's peak power. Using a prop with less load should allow the engine to run at a higher rpm, and that increase in RPM might more than compensate for the decrease in pitch.

It also depends a LOT on the airframe. A low drag plane will allow the engine to "unload" more, allowing you to use a prop with a higher static load. With a higher drag airframe, the engine is going to work more with the same prop, so it might benifit from the lower-load prop.

Different people will sometimes prefer different props on the same engine/airframe as well. So, give it a try, and see if you like it. If you don't, then put the first prop back on. Or try a 3rd size. Messing around with props is almost always worth doing.

Once you get to the point where you can fly a lot without problems, go buy all the props you can find around the size you think you need. You will probably find that one or two of them work noticeably better for you than any of the others. Keep the others. When you get another airplane and/or engine of similar size, you may find that one of your discards is the best for that combination.

Try an APC 11x5 while you are at it. You may find the same speed with much more prop. The Senior seems to hit a top speed and that is all you get unless you go with the next engine size up.
Have fun, it's a great plane. MikeB