Scratch Mini Skywalker - Hep Needed!

by ProjectFlightDesign | March 18, 2013 | (7) Posted in Projects

Here is my mini Skywalker scratch design. It has a 50 inch x 8 inch wing with a KFm2 airfoil, with the step made from 1/2 inch pink foamboard from Home Depot.

PLEASE LET ME KNOW IF YOU HAVE ANY TIPS FOR THE TURNING PROBLEM!

Wing: 50" x 8"
Fuselage Length: 50", 10.5" in front of wing, 12" boom behind wing before the tail starts

Motor: 2212-13, 1100kV and 50 grams
Prop: 10x4.7 APC
ESC: 18A Exceed RC
Battery: 2500 mAh, 11.1V 3S lipo GensAce 25C
Servos: 9 gram
Rx: OrangeRx 6 channel DSM2 compatible
Tx: Dx7se

COMMENTS

kelvinabrown on March 20, 2013
At a guess I'd say your tail boom is flexing when adding elevator thus reducing the response.
I might have to build something like this, looks simple and effective.
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ProjectFlightDesign on March 20, 2013
The elevator control seems fine though. Maybe I should stiffen it up
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Miracle Air on March 20, 2013
Thrust angle?
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ProjectFlightDesign on March 20, 2013
Someone else mentioned that too. I think that I am going to try to add a few washers on the right side and see what happens
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Miracle Air on March 20, 2013
I like this plane a lot. I run a high school RC club and I bet the kids would love to build this. I'd love to see the dimensions on it. Kf1, yes?
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ProjectFlightDesign on March 20, 2013
Thanks! I put some dimensions above. Its a great plane - aside from the turning issue - which I believe can be resolved - its a KFm2
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Dirt Pilot on March 20, 2013
What is the vertical angle on the motor mount? You could be pushed to the right with the P-Factor on the propeller. If the propeller on the left side has an effective higher angle of attach, you get more push from the left than right. This makes it harder to turn left and easier to turn right. If the propeller is more perpendicular to the effective air flow, you will get less P-Factor. I also notice your tail is sliding in the left turn. Make sure you have as much left throw on the rudder as you do right throw. The torque on a right spinning motor should actually be helping you bank left. See if your plane is laterally balanced. However, the plane is banking. It just isn't turning. The elevator could be twisting as well (boom flexes in torsion).
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ProjectFlightDesign on March 20, 2013
Thanks for the repsonse. Lots of ideas and things to think about. I have about 3-4 degrees on the vertical angle of the motor
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Auxiliarypower on March 21, 2013
I think I will build the same plane this weekend and see if I have the same issue.... I will update later.

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ProjectFlightDesign on March 21, 2013
Let me know! I am curious to hear
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PandaFish on March 23, 2013
Beautiful plane! I loved watching it fly, it just floats - Simply gorgeous.

About the problems hangin' a louie -
Step 1. Hold the prop and put a finger on the back of the tailfeathers - Check your axial balance.

Step 2. Take a look a the plane and how the contols move on the ground. Specifically, the rudder and ailerons.

I like to cut a small sliver out on the sides of my ailerons - So the control surface doesn't 'brush up' against the rest of the wing - If you wing bends, even slightly under load, it can bind up the aileron! Try holding the plane by its wingtips and use the ailerons - this will help aggravate any binding.

Make sure you don't have a lot of slop in the connection between your horns and control rods. try moving the surface with your fingers - Does the rod bend? The the surface move a lot?

Apply some (SLIGHT) pressure against the control surface and try to move it with the transmitter - Are both servos putting out the same amount of power?

Check your transmitter and the endpoints for the servos. Sometimes all those values conspire when you are not looking.

Lastly look to see if your tailfeathers move when you work the rudder. Try the rudder and elevator at the same time. Apply SLIGHT pressure while doing so - Any control rod bend? If the tailfeathers move, some simple BBQ skewers make great bracing!

If I had my bet, I'd think aileron binding as the wing flexes. But please let us know what turns up, buddy!
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Scratch Mini Skywalker - Hep Needed!