Correct Alignment
 

Hi,

We built an RC plane for our college senior project. We are test flying it next week. Im worried because when we assembled everything, the horizontal tail is not prefectly parallel with the wing. One side of the horizontal is higher than the other. Also, the electric motor we when we permanently installed it, ended up just slightly misaligned to the left. Should we still go test fly it, or there's a great possibility it will crash?

Any inputs will be helpful.

RE: Correct Alignment
 

If the horizontal stabilzer is only a little bit out of alignment it'll fly ok, although it may want to veer one direction. You should be able to correct that with your aileron trim. For your motor, aligned to the left is going to make it want to pull to the left. Once again, corrected with trim. However, there is a simple solution for the motor. Simply place washers under the left side mounts for the motor, which will cant it back towards the right. Motors/engines on planes are usually built with a little right thrust into them to correct for left thrust caused by the torque of the spinning engine/motor. So you'll want to get some right thrust into it if you can. If not, try to get it as close to center as you can.

Ken

RE: Correct Alignment
 

Dean Pappas did a 3-part article called "Trimming from the ground up". It's an excellent read & should help you with your initial trimming activities. To quote Dean on determining the thrust angle: "The simplest way to measure the right-thrust angle is to measure the distance from the propeller tip to the tail post on both sides. Either use that trigonometry you forgot or remember that with a 12-inch propeller, 3/16-inch difference equals 1 degree.". A typical right-thrust is 2 degrees right thrust - aka 3/8". Most of us have long forgotten the trig functions necessary to "do the math". :eek:

Our club works closely with the aeronautic engineering department at the University of Colorado. I have a big smile on my face because the CU students just hand the plane to one of our members and asks what they need to do next.

HTH,


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RE: Correct Alignment
 

I'd agree with Ken that fixing the motor thrust is more important than worrying about the stab.

More important than either one is the CG. If it's out of balance, it will be a bear to fly. You also want to triple check your control throws - both the directions and the amounts.

Do you have an experienced pilot in your group?

RE: Correct Alignment
 

first question when you say the motor is angled to the left are you talking about looking at it from the front or from the back. all the people here know to use sitting in the pilot seat as there reference ofr left and right and most plane are built to have an automatic right thrust. so is your thrust really left or is it right. Left thrust on a trainer will make it fly a lot more funkyier then you would expect. otherwise all the other alignment settings on a trainer are fairly forgiving if they are relatively close

RE: Correct Alignment
 

Oh, its slightly pointed left looking from the front (about less than 5 degrees i think). from the back its to the right.

RE: Correct Alignment
 

Sounds about right then.

RE: Correct Alignment
 

oh really? Coz we didnt know that there is that right thrust that u have to built in to the motor. Anyways, thanks, we`ll be able to test fly it next week and hope everything works out. Coz thats just the problem we have right now. CG is on its proper location so, i hope it`ll turn out well. Thanks.

RE: Correct Alignment
 

Be sure to post a video of the flight

RE: Correct Alignment
 

i will try. i hope if the weather cooperates with us so test flight will go as planned. thanks again.

RE: Correct Alignment
 

Well,

Just asking outta curiosity, as you guys are doing the project, I wish you all the best & success in your project, any of your guys have been flying the r/c plane before. I mean would you have to do the buddy box or this is your project and some other intermediate or expert flyer is gonna fly the plane for ya'll?

RE: Correct Alignment
 

Ya, we have some RC pilot to test fly the plane for us. He havent seen our project yet so thats why i asked this question before hand.

RE: Correct Alignment
 

Well,

As Back in my local country now USA is my country:D I met few engineering university students doing the project with a cam onboard, so they had one of our senior flyer made them a model, they didn't build it themselves, and their project went pretty well, and they had him fly their plane and contacted me to fly their plane but somehow things didn't catch up. Anyway, all the best to your project.

Mody