How do you know what size spinner to run? I am replacing my 10x4 3 blade Evo PTS prop with the common MAS 2 blade 10x6, for starters. I used a 2", which was very close to what was OEM. I hear people saying run 2.5 to 2.75 spinners...............what determines this?

Will the 10x6 load the motor harder than the 10x4 3 blade? I still want docile handling for the wife, but dont want to overev the motor. The two blades seem to be the best option.

Spinner size is determined more by the plane that it's going on than the engine/prop size. Most times spinners will be sized to blend in with the lines of the cowl, or the fuselage of the plane.

Ken

An old Aeromodeller Annual has a statement that the most aerodynamically sound spinner is 1/5 the diameter of the prop, say 2" for a 10" prop.

2" or 2.25" should work well. An 11x5 or 11x6 will give better take-off and climb performance.

Guys, I have a query to send and would like to hear your feedback.  Ihave a World Model P51 Mustang size 46.  Engine is OS 55AX 2-stroke.
I installed a Tru-turn spinner 3" and a 3-blade 13x8 propeller. 

Is this alright or am I killing my engine?

Anybody try 11x8 3-blade on P51 size 46 ?

Thanks in advance.

A 10x7 would be a better 3bl prop, standard for .60's, 13x8 will have the revs down to a place where little power is being developed, you won't like it at all.
Evan.

You might check the response to your almost identical question in the "how to choose a propeller" thread.

If you can find any size 3blade you wonder about, buy it and try it. The "rules of thumb" and "convention wisdom" about 3blades is so far off the mark, and so very, very few people have real experience flying 3blades that the only really dependable way to find out about 3blade props is to try everyone that you can find to buy that even looks like it might work for you.

As for spinner size......... you chose a scale model, why use any spinner that doesn't fit?


BTW, the answer in the other thread covers actual testing and experimentation of 3bladers on an OS55AX.

I have recently started making the switch from spinners to prop nuts. They make it so much easier to change props, and they don't get chewed up by the starter. On my last three planes I have used Dubro aluminum prop nuts, and I am gradually replacing the spinners on my other models.

http://www3.towerhobbies.com/cgi-bin...?&I=LXE158&P=0

Prop nuts are great. And they look pretty good also, even the chunky style. http://www3.towerhobbies.com/cgi-bin...?&P=9&I=LXL745

Do regular electric starters work with these prop nuts?

Mine always has.

Yes they do.

Thanks

Hi!
Yes! All you do is reverse them.

On the ones I am using, the prop nuts fit into the same starter cone at the 2"-3" spinners. I don't even need to reverse the starter cone insert.

I think you may need to reverse the insert for the Harry Higley nuts.