Hi!

Recently started flying a SkySurfer and am throughly enjoying the same. However I realise that despite the rudder working well - the plane does not respond and I need to use the ailerons to turn the plane.

Can anything be done to improve on the performance of my plane?


Looking forward to your comments on this

ATK

Quote from: Adel on January 11, 2021, 08:39:01 PM
I realise that despite the rudder working well - the plane does not respond and I need to use the ailerons to turn the plane.

I checked with another member of this group who told me that due to the SkySurfer's big size as compared to the small rudder - this is happening and that this is intact a design fault. He also said that he had installed the original Emax Servos and even then the performance of the rudder was unsatisfactory.

Can anything be done to improve on the performance of my plane?

Please do not bad mouth a good design.
Design fault, eh? Whoever told you this, how many successful models has he designed?
I'm not posting the full answer here, as it may offend you.

If really interested, PM me.
I'll answer privately or publicly, as you wish.
Regards

@adel,
To avoid being sued by the owner of RCBazaar, I suggest you remove the word 'unsatisfactory' from the title bar.
Regards

Tried increasing the throws?

Good to hear from you!

I am using TowerPro MG 90 servos. I have also increased the throw of my rudder servo to the maximum on my transmitter. Besides this I have also made the foam hinge flexible. Can upload a video of this if that helps.

Quote from: sanjayrai55 on January 12, 2021, 05:10:20 AM
Tried increasing the throws?

Try checking the rates and expo on your Tx. Reduce Expo on Rudder to 0

Thanks for your advise. Done as you suggested.

I am keen to know how the response of the rudder could be increased?  

Looking forward to your hear from you!

Quote from: K K Iyer on January 11, 2021, 10:33:55 PM
@adel,
To avoid being sued by the owner of RCBazaar, I suggest you remove the word 'unsatisfactory' from the title bar.
Regards

Quote from: sanjayrai55 on January 12, 2021, 10:42:51 AM
Try checking the rates and expo on your Tx. Reduce Expo on Rudder to 0

The expo is 0 on my transmitter for the rudder and the dual rate is 100.

Then I can't help unless I actually see the model. I've flown a Sky Surfer - the rudder response was fine. Not a design issue - something else is wrong

Would a video of the the servo and the the rudder moving help in identifying the problem?

Quote from: sanjayrai55 on January 12, 2021, 10:50:47 AM
Then I can't help unless I actually see the model. I've flown a Sky Surfer - the rudder response was fine. Not a design issue - something else is wrong

I have a skysurfer for a long time now... i don't see any problem with the Rudder it responds perfectly.
Guess it can be a servo throw issue.

Which servo do you use?

Post the video. You might be using the wrong holes in the servo arm and getting less throw. Or your pushrod may be flexing under load

@adel

After all the servo, linkage, throw etc, let's look at the basics.

I wondered if you were flying without ailerons, depending on rudder alone. But a look atyour first post clarified that you have ailerons.

Rudder alone can only initiate a YAW, not a turn.

A TURN requires the wings to be banked. Then the lift vector has a horizontal component that causes the change of direction of the flight path. The easiest way to bank is by using ailerons.

If ailerons are not there, dihedral is needed. The rudder yaws the model, so the outer wing gets an upward lift, leading to roll, and then to the turn.

Usually an aileron equipped model will have less dihedral than required for initiating a strong turn with rudder alone.

In such models, the rudder is usually used for steering during takeoff, And in crosswind landing.
Turns are done with ailerons (with a touch of up elevator or throttle)

My 64" Sunbird doesn't have ailerons, though designed to have them.
It turns just fine with rudder, because I increased the dihedral

So my suggestion is to use the ailerons to turn, and forget the rudder except for crosswind landing.

There are of course more issues involved, like coordinated turns, adverse yaw etc, which can be gone into if required...

Hope this is of some help.

Regards

Many thanks for your detailed reply.

I have read it carefully and do understand the point that you are making. Have been using ailerons to turn. Whenever I attempted to use only the rudder I did not manage to turn the airplane. Now I understand why this was not happening. However I still feel that the throw could be an issue. But I do not know how to increase the same. Would be uploading a video of the same asap.

@adel,

I don't understand why the preference for rudder when you have ailerons.

An easy way to increase the rudder power is to increase it's area by adding some plastic sheet or depron.
But this will only increase the yaw, an inefficient way to turn.

A powerful rudder may be needed only for knife edge flight, or super quick snap rolls, neither of which is part of the Skysurfer's intended flight envelope.

But then, to each his own...

Thanks for your reply.

I wonder why I am unable to post a video in this thread. When I click on add file it does not respond.

As I could not post the videos here have sent them to you on email.

Would be grateful if you could have a look and see

thanks

Adel

Quote from: sanjayrai55 on January 12, 2021, 04:16:51 PM
Post the video. You might be using the wrong holes in the servo arm and getting less throw. Or your pushrod may be flexing under load

Hope you don't mind; I took the liberty of uploading to YouTube and posting here for a wider reach

My comments:
1. Rudder movement is more on one side (right). Correct this
2. The throws are too low
3. Move the Z bend on the Rudder end more inboard - i.e. closer to the rudder. This will increase the throw

The throw should be more than 30 mm in each direction

To post a video on RCI, you have to convert to  YouTube

I can't make out clearly, but the rudder pushrod seems to be bending

Firstly correct the pushrod bending. Use a stiffer rod

After that if the rudder movement is unequal, check the servo

Which mm pushrod should I use?

More than 2 mm won't fit in the linkage stopper. What's important is the stiffness

Use spring steel if you can

Quote from: sanjayrai55 on January 13, 2021, 11:40:04 AM
More than 2 mm won't fit in the linkage stopper. What's important is the stiffness

Use spring steel if you can

Yes, Also it needs to pass through the silicon tube that came with the airplane.

Any ideas from where one could get spring steel that would work?

I maybe a bit inexperienced when it comes to sky surfers but I think another reason why the pushrod is bending so much is because of the linkage stopper. Consider using a z bend if possible.

Regards