rcworld2000

its a 46 la

dabigboy

Seems like you are making some progress....good! Stick with the Cub if you can, they are pure joy to fly once you get the hang of it. I am in the process of restoring my old GP Cub .40 right now as a matter of fact, it was always one of my favorite models to fly. They fly MUCH more like a full-scale aircraft than your average sport RC model. And while they punish bad stick-and-rudder skills, they reward good skills.

Matt

thailazer

RCWorld.... A flat bottom wing will tend to want to climb with zero incidence on the wing and horizontal stab. You might want to add some down trim on the tail as suggested in an earlier post. A plane that has some up trim in the elevator will definitely be a handful to control but an experienced helper pilot should be able to diagnose that fairly quickly. Good luck and keep at it. Sometimes planes take a little debugging until they become good flyers.

do335a

"My trainer was against me changing cg point he thinks the plane needs aileron differential which I am also going to add.

wish me luck."

That's totally idiotic. Aileron differential has absolutely no impact on how the plane flys due to CG location along the longitudinal axis. Period. It will impact yaw and roll.

You need a new instructor - preferably someone who knows how a plane actually flys.

jester_s1

Let's don't be too quick to judge the instructor. The instructor actually saw how the plane flew and made recommendations based on that. All we have is the description of an inexperienced pilot of how the plane flew and the second hand telling of the conversation with the instructor filtered through the understanding of the inexperienced pilot. If the plane has a CG problem and the instructor wasn't worried about it, then maybe he really does need to get a second opinion on that. Some instructors for whatever reason aren't interested in helping new pilots get their planes set up right. But that still doesn't mean it's time to stop working with that instructor. He may still have some good things to teach, and he may be the only one available.

rcworld2000

He's a great help. And many others helped.. he was worried aabout both points. And both did help. He just was making g suggestions towhat maybe the ccause of how the plane was reacting. But I should state he really has never flown cubs..

52larry52

My Feedback: (1)

Your last statement, "But I should state he has never flown cubs" is very revealing! I think the instructor is learning about Cubs right along with the student.

Ken Erickson

If it is an LA, use an 11 X 4 APC prop. You are going for Thrust, not RPM or speed.

(Edited)

By golly, I noticed in post #51 that you wrote that it is an LA. The plane in my Avatar uses .40 LAs or FPs or GPs. All very similar to your LA. We all use 11 X 4 APC props for the thrust .

You will get less than 12,000 RPM.

Ken Erickson

rcworld2000

i have a 11 x 7 on there now?

JohnBuckner

My Feedback: (1)

An 11 x 7 is to much load for a .46LA If you want to use an 11 inch prop you need to use a flatter one more like a four and no more than a five. Yes APC makes those sizes.

John

jester_s1

Geez, who told you to put an 11x7 on that engine? That's a prop you'd use on a hot .60.

52larry52

My Feedback: (1)

For what it's worth.....I have a 71" wingspan World Models J-3 Cub ARF, powered by an O.S. 46LA, and I use a Top Flite 10x6 wood prop. Works fine for me. I like the look of a wooden prop an a Cub but a 10x6 nylon prop would be fine also and less prone to damage from prop strikes if your still working on your taildragger landings.

52larry52

My Feedback: (1)

I just checked in an O.S. Engine owner's instruction manual...... for a 46LA it lists an 11x6 as a "running-in" prop and an 11x6 and an 11x7 as a "trainer and sport" prop. So, I guess O.S. thinks a 46LA can spin an 11x7 but I tend to agree with John and jester that a little less than an 11x7 would be better. As I said my 71" Cub uses a 10x6, and I still have two fourty size trainers collecting dust in my hanger, both with 46LA power, one spinning a 10x6 and the other spinning an 11x6. For your Cub I would drop down in pitch and maybe diameter too. Try several sizes for yourself and decide.

thailazer

My 71 inch Flair Cub flys well on the ASP-46 with either an 11-6 or 12-4 Master Air Screw. I've also used a 10-7 three blade on it.

Ken Erickson

Guys,

Use an 11 X 4 APC!!!! I currently have 6 airplanes running OS FPs or LAs and clones, They are trainers or aerobatic trainers. The most thrust is achieved with either an 11 X 4 APC or an 11.5 X 4 APC. Using a 10 X 6 will take 3 times the length to get off the ground and have lots less thrust.

You will get a bit less than 12,000 RPM and lots of thrust to pull you out of bad situations.