I have a GP Big Stik 60 ARF and Magnum 91 FS. What prop(s) should I get for this combo?

I was thinking 15x4 and 14x6? I know that a 13x8 works on this engine as well, but didn't think it would be a good prop for this plane given its design. What do you think?

Cost wise, the 13x8 props sure are A LOT cheaper than a 15x4, but I would think that a 15x4 would be a better choice for aerobatics given the high diameter and low pitch. Would the 15x4 be that much better than the 14x6?

Also, does it matter what kind of prop I get (material wise)? This is my first 4-stroke engine and am not sure if they are picky on what props they can use or if I can use wood and composite props. Can I use a basic Top Flite Wood prop?
So far I have looked at these props-

APC 14x6 Pattern* Propeller
Master Airscrew 14x6 Maple Wood Scimitar Propeller
Master Airscrew 14x6 K Series G/F Nylon Propeller
Master Airscrew 15x4 K Series Propeller
APC 15x4W Propeller

*Does the "pattern" designation have any significance?

Sorry for all the questions, just want to make sure that I buy the right props.

Thanks for the help!

of course it depends on your flight expierence but for a 91fs a 14/6MAS is a good start I like the plastic composit props they do have alot of flex in them but one prop strike and you are replacing the wood ones until your used to flying a particular plane start with a plastic or composit prop all the props you have listed will work it has alot to do with ground clearance the wood ones have alot less flex in them but they don't last long if you are not making perfect landings.

My experience has been that APC props are by far superior to MAS. MAS will take a prop-strikle better, but if you are confident in your abilities, get the APC.


APC 15X4 W will give you quicker spool-up and a lower top speed. I don't think top speed is important at all,. so I would get the 15/4 W from APC. Also, the 15/4 W will slow you down a bit better when you throttle-down.

That plane is not a SUPER aerobatic plane, but I learned to hover on a stick plane. They can do a lot more than you would think, but I could never get into a good KE with mine...probably my fault as usual.

You just can't go wrong with any prop on your list, but APC is best for performance, MAS is best for durablity. I think you should stick with a plastic/nylon prop. Wooden props in that size range are just not that great for learning new things.

I fly a Big Stik 60 size with an Evo 1.00 on the front.I like the MA 14x6.I have used the APC but didn't like it as well as the MA.That is just a matter of personal choice.The Stik will do just about any manuveur you want,with exception of a good flat spin.KE takes some compounded stick inputs but very doable.I can KE the field in big ovals with mine and reverse directions and do so in the opposite direction.

I am a fan of the 14x6 for general flying with a 91 four stroke.

Master Airscrew now has a 14x6 in their "Scimitar" line, which I have on my Big Stik 60 with OS 91 four stroke. It has less flex than the K series if that's important to you.

Since the only 14x6 APC makes is labeled "pattern" I doubt there's much significance, and if you want APC it's your only choice.

I was curious about the pattern designation since most of the the APC props are listed as being a "sport" prop on Tower's website. IE- The APC 13x8 Sport Propeller.

I take it that I shouldn't bother getting a 13x8 prop for this plane then?

I also run a 14/6 MAS on one of my OS91fs and it pulls pretty good no complaints its a warbird so I have the K style square tips.
MAS also has some decent 3 blade props on my Hangar-9 P-40 I am using a 14/9-3blade and it moves through the air pretty fast the 91fs doesn't have any problems spinning that prop at all.

If you use a Master Air Screw make sure you take the time to balance it. Only thing I don't care for on that mfg. is how bad the balance is. APC props are pretty close off the rack and can get by if not able to balance. Make sure on any new prop you use take the time to sand the sharp edges. They can cut like a razor blade. Most of the sizes that you mentioned are ok. For power go with a long prop with little pitch.

Hmm... a 3-blade ehh? That sounds pretty cool. Is there a rule of thumb for what size to use for what engine? Is there any benefit to running a 3-blade prop? IE-does it spin up faster, is it mostly cosmetic, or...? I had thought that you had to drop down a size in diameter when going from a two to 3-blade prop, but if you're using a 14x9 3-blade that must not be the case? I would think that the 14x9 would really lug the engine with an extra blade and a relatively high pitch; what RPM are you turning with it compared to, say, a 14x6 or 15x4?

Has anyone put a 16x4 prop on a 91 FS or is that just crazy? From the responses I have got here, I think that I'll stay away from wood props until I get used to the plane.

As for balancing props, I have never ran an engine w/o balancing the prop first. My logic is if you have a balancer, why not use it?

rule of thumb drop 1" of dia.for each blade added the OS 91 will spin a 15" prop in the rec. range the 14/6 will spin up to 10,500 the 3 blade gets about 500 less rpm but I seem to get alot more speed out of it with the higher pitch prop at a lower rpm + I like the look on the ground I dipped the tips in wt paint the 3 blades come with no painted tips MAS has a pretty big selection of prop sizes I havn't settled on one particular size just trying diferent ones out to see what performance I get

In my mind the Stik seems to be made for flying at a slow or medium speed.
At the same RPM you'll most likely have less pulling power with a 13 compared to a 14.
The Stik is not a very 'slippery' design, so the 8 pitch might not gain a lot of speed over the 6.
Of course, you might bolt on the 13x8 and like it better than any other.
We all like different things when it comes to props.
My brother tried a Graupner 3 blade (not sure of size) on one of his 91s and swapped back to the 14x6 after two flights. I think the plane was his Super Sportster.

Looks like I'll just stick with a 2-blade for now since, as many of you have pointed out, this isn't exactly a speed plane. I'm about to place my order at Tower and decided to try out a few 15x4 and 14x6 props. Once I get the engine broke-in I will mount all of the different props and report my findings.

Thanks for the help everyone!

i have a big stik 60 with a supertiger 75 two stroke. it is awsome. it really moves out anywhere you point it it goes. if you look on the box it is the recomended engine for the plane. i use a 11/9 prop like i use on all my planes. for 109.99 go for the supertiger. dallor for dallor i put them against os anyday. and are just as reliable. i use them on all my planes. its just a sugestion to everyone with one . this is the perfect setup for the bigstik 60...

You might want to consider an APC 16X4W. great torque and lower top speed. works great at low rpms'.

Bruce