sowega flyer

I'm wondering why the Master Airscrew "K" series is recommended for 4 strokes, and how will the performance be when used with a 2 stroke. Is there a difference? I bought a "K" series prop to run on my .61 before I knew the recommendation. I want to run that size prop but all the LHS has is the "K".
Thanks!
Jason

mtwister

They are just a wider series prop that are optimum for 4 strokes.

CoosBayLumber

My Feedback: (1)

They also are not for the RPM that two strokes are capable of. If a four c prop is used on a two cycle engine, and it comes apart, injures someone, it is then your baby for responsibility. And it don't matter at what actual RPM it may have come apart at.

Wm.

meaden

I doubt the K series prop would fly apart on a 2 stroke engine. Since they are wider (more weight) it should just add more load to the engine (reducing the RPM) I think it would just be less efficient than a 2 stroke prop. 4 strokes have more torque an can swing a bigger (wider, longer and heavier) prop at a lower RPM than a 2 stroke.

Flak

My Feedback: (1)

I have a Super Tigre 90 2 stroke with a "K" series Master Airscrew prop and it performs very well. Bolt one on and fly the heck out of it.

jaka

Hi!

All Master Airscrew props should be avoided if you want good performance.
For best performance choose an APC, Graupner , RAM or Bolly plastic prop.

Flak

My Feedback: (1)

Jaka,
What are you saying? I use Master Airscrew props on all my Warbirds that call for a 3 blade prop and they work great.

sowega flyer

Thanks for the responses- I appreciate everyones input. I figure I'll give it a try, my main concern was that if it was made to spin less RPM's than a 2 stroke would it flex so much that the pitch would change. I can't tell if there is any difference in composition.
Jaka- I have an APC prop on it now (I'm talking about a seagull extra 300 .60 size with a .61, swinging an APC 11x7 prop for break-in) I wanted to move up to a 12x6, just to see how it does. I will probably experiment with other sizes until I find the one I like. If anyone knows the best prop for this combination- let me know!
Thanks
Jason

carrellh

Jason, do you plan to do 3D flying with the Extra? If so, you might consider the APC 13x4W (3D-Fun Fly).

sowega flyer

Thanks carrellh,
Right now, I'm just trying to fly typical sport stuff. I'm not even sure if I have enough experience to keep this plane in one piece without trying 3D! LOL Thanks for the suggestion, though!
Jason

carrellh

I used a few different props on my 61 (on the trainer) and they all worked OK

APC 11x7 - recommended by TT, first prop I tried. Idle was high enough it didn't like to land unless we kiled the engine on final

TopFlite 13x5 wood - seemed to be too much load on the engine, but maybe it wasn't broken in.

MA 12x6 K - probably was best overall for my combination and experience level

APC 13x4W - I liked the performance better than the rest but broke too many of them $$$$. The thrust and climb were great. It seemed like the big heavy trainer would almost jump off the ground. Speed was OK for the trainer, and probably would be Ok for a lot of planes. The only negatives were related to my lack of skill in landing, and the $8 price tag per prop. I seem to have problems keeping the nose up. I had 3 of these props. I broke 2 in one day. I went back to the MA 12x6 K series after that.

rc-sport

My Feedback: (12)

Flak, try a Graupner 3 blade, you'll end up taking your MA props and use them to pick mud out of your boots instead

jaka

Hi!
Well ! Then you haven't tried a 2-blade APC , RAM, Graupner Cam-prop or Bolly?!

HighPlains

My Feedback: (1)

And this leaves the other end still clean to stir paint with.

They seem to be the prop to use if you can't land without hitting the prop. After you learn to flair, they have the secondary uses around the house.

falcon7a

Sowega Flyer,

How was the performance with the K-Series prop on the 2-stroke? I am planning on using the MA 12x6 K-Series on an OS 55AX for 3-D flying on a Groovy 50. Since they are wide blade props, I can probably get good torque from them without overloading the engine with a 13x6. I only use 5% nitro.

andrew66

someone should do a thrust test with several different props of the same size. i think that the results would be alot different than most people would think....

mrbigg

My Feedback: (21)

I've used these props twice now. I have a 13x6 on a ST .61 spinning at about 10,500. It's on a trainer and is my favorite prop for it.
I just put a 14x4 on a used Saito .82 and was getting around 12, 300 to 12, 500 so I richened it to 11,800. Pulls my profile great.

chashint

Everyone send me a bunch of 12x6, 13x6, and 14x6 props (or 3 blade equivalents) and I will do the thrust test.
I would also like to test the props for consistancy so several of each brand would be best.