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Pumpkin drop event

Please help finding plans and help with current plane.

semvdm

Junior Member
#1
Hey guys,
Atm I'm flying a Robbe Student (O.S. 25FP 4cc Motor) but when I'm taking off it want's to turn to the left to the point that I can't help it and have to ask someone in the club to help, does anyone has some ideas how I can remedy this.
robbestudent.jpg
Second I want to ask if someone has/can find plans for a lancair 120 (also know as lancair 360 mk II) because I can't find any.
I really want to go fly low wings because at this time I can fly, aerobatics and land with this plane but I want to learn taking of and new trick my current plane can't do.
rc plane.jpg
Also if anyone has plans for an Alula i would like to get them too if possible.
alula.jpg
Thanks in advance.
 
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#2
Plane in top of top picture is this the one that turns left ?

Check the wing alignment looks like the left wing (Port) is low compare to the right (Starboard) from eye sight only, but plane is dihedral so that alone would not be the problem.

Also check the horizontal stabilizer for the same problem

Check the balance of the plane port to starboard, for and aft. The CG point in those type of planes are normally 1/3 wings chord in from the wings leading edge. just behind the pilot seat and in front of where passengers may seat.

I have no idea if it would be prop pitch or prop drag I am not experienced enough in RC to be able to answer that question but from a model builders point of view the model is what I would check first.
 
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#4
If you have checked and double checked all surfaces, balance and CG is correct then the only thing I can think of is Prop Thrust/Prop Torque related issue.

I would love to help you with this but I have no experience with regards to that and remote controlled planes. I guess you could look up the motor type and use a prop the manufacturer recommends see if that helps.

I can only hope someone else jumps on this thread with more knowledge than me on the subjects of "Props" and Thrust angles with regards to RC planes and motors.
 

AkimboGlueGuns

Biplane Guy
Mentor
#5
Add right thrust to the motor. The left turn tendencies are caused by "P-effect" which is more commonly known as torque. This is actually an effect on all fixed wing single prop aircraft. The prop spinning causes the fuselage to move to counteract the torque. The best thing that you can do if the thrust line is correct is advance the throttle really slowly and apply right rudder on takeoff roll.
 

FAI-F1D

Free Flight Indoorist
#9
Here's my $.02, probably not even worth a tenth that...

1. In terms of the model pulling to the left, we teach full scale pilots to be ready to pretty much stand on the right rudder pedal on takeoff in high performance aircraft because of the torque effects. That being said, you also need to check the alignment of your nose gear to verify that it's tracking correctly. Also verify that your rudder is correctly aligned, and that the wing has no warps (even a slight one on a model of that wingloading is going to have major effects).

2. The Lancair has something of a bubble canopy, which is going to be big enough that you might have trouble molding your own. I'd recommend looking for a kit to build it from. You might be able to find a "short kit" which includes the canopy and laser cut parts, but lets you pick up your own hardware and strip wood--those kits are considerably less expensive, at the cost of a little more work on your part.

3. I can't direct you to the plans for the Alula, but your first stop when looking for plans should be www.outerzone.co.uk. Specifically for the model you're looking for, Hobbyking makes an ok balsa kit for a flying wing DLG styled after the Alula. The kit is not of exceptional quality, but it's cheap and the model flies quite well from what I've heard.