Before launching a rebuilt Cub

[realbob]

I tempted to fly my modded Cub last summer and it crashed very very hard. (FInally found that my TX was defective and loosing signal /$?%&).

I now rebuilt it with brushless and adjusted the COG. I have couple questions:

1- Is it normal while doing some taxi that the cub is always going to the right? I assume that since motor is much more powerfull and with the motor mount angle must be normal?

2- How much mm (or inches) should the elevator go up and down?

3- How is the left-right balancing part important? I remeber that when flying stock, I changed battery and it was unbalanced and flew great.


Thanks!

[realbob]

NO one here?

[gagallagher04401]

Nice thing about the cub is setup is forgiving, for the most part, have to be in the ball park at least.

1. as you taxi I would not expect the plane to track perfectly straight, just correct it with the rudder.

2. elevator up and down I am not sure of the actual distance, remember by moving the clevis to the outer control horn holes it will give you more throw, and vise versa if you go the other way. Move the clevis to the other holes on the servo for more throw as well.

3. Lateral balancing is important, it will effect your loops etc, when pulling back on the elevator. It is easy to check, loop a piece of string around the the motor shaft behind the spinner, and loop a string around at the back of the plane, pick the plane up with the loops of string. Does either wing drop? If so add a little weight to the wing tip that raised up, until you can lift the plane and neither wing drops and the plane stays level.

I am sure other people will chime in, go fly that thing!

[flydiver]

Motor torque will make it track right. Probably a bigger problem is crooked landing gear.
That's what the rudder is for. You don't mount the motor offset for taxi, you do that for flight.

Rudder/elevator travel is a personal setting. The slower you go the more travel you need. The faster you go less travel is needed.

[realbob]

Thanks for all the info here!

But if my landing gear is new and aligned, and in taxi mode even with rudder to opposite direction I still turn right.... Something wrong or could be normal ?

[flydiver]

Why do you think it's aligned just because it's new.
Have you landed it even once? That's more than enough to bend it.

[realbob]

Hi, didn't took off yet. Waiting a no wind day! Very windy on my day off
But also not perfectly lateral balanced so could influence also I guess.

[gagallagher04401]

You need to have enough air moving past the rudder in order to make the plane turn as well.

[gagallagher04401]

It will fly, go fly it

[realbob]

Hi again, tried to make it fly today.
Lost a wheel during take off (I am bad on wheels, always loose them.... aven with thread lock and added some silicon on the end...) Had hard time turning to the left, but the wheel I lost was on the left side (They are large 3'' wheels). Would this make a so big difference in flight?

[iandhunt]

Not really, the Cub is about as aerodynamic as a bus with all the drag it produces due to its shape. It is not gonna be affected too much by a larger set of tires. I fly 3-3/4" super light DuBro's and don't really notice that much of a difference in flight. I replaced my nuts with a 4-40 nut with a squish of Lock-Tite to hold it in place. Luckily the cub is a tough old bird and a forgiving plane so it should fly relatively easily. As long as the Center of Gravity is correct!

[blackthunder]

When I added by bigger wheels, I noticed the wheel holes were to big for the landing gear, so brought a bit of brass tubing and basically made a brass bush on the landing gear for the wheels to sit on, then they don't vibrate/move as much anymore!

[realbob]

OK, but since I lost a wheel during flight, only 1 left, could this influence why I was almost unable to turn left?

[iandhunt]

Lol. Um, yah. I presume that more drag on one side will cause a turn to that side.