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Help me please

#1
For a project in school i am building a plane, and have gone threw 16 renditions and none of them work, their either to nose heavy, too tail heavy, arent stable crash on its maiden flight unexpectantly. Please give me plans or ideas.
 

Vimana89

Well-known member
#2
You will find tons of good info here. Does your plane have to be of your own design, or would a kit or printable plans be appropriate? If it has to be, or if you want it to be your own design, there are some factors to look at and think about, that would otherwise be solved and the thinking done for you were you to use a kit or plan. What type of plane is it, where is the prop located? The most basic issues that usually mess up home designs are usually related to motor thrust angle or center of gravity. If it isn't one of these two things, some other common issues are wing loading(your plane is just straight up too heavy), electronics or linkage issues, or pilot error, such as over-controlling(especially bad on a touchy or rough design, and even worse if your transmitter does not have expo.)

So the main questions are, what type of plane is it?(pics help). Is it your own design from scratch, or your own design based on a historical plane or proposed model or current RC plane? Is it a kit, or maybe a plan you found somewhere or purchased? What materials are you using to build it? Dollar store foam board or other? What is your electronics setup, and what sort of transmitter are you using?
 

Michael763

Well-known member
#3
Not sure of your school project requirements are. Could you change a bloody wonder or a tiny trainer to fit your needs? I have seen a lot of people do their own mods to these airframes.
 
#5
The guidlines are it needs to be my own design, it it has to maintain flight. I have mashed a couple designs together to make different planes.
 

DamoRC

Well-known member
Mentor
#7
Another important consideration might be your piloting skills. Is this your first plane to fly or do you have previous experience flying RC planes?
 

DamoRC

Well-known member
Mentor
#10
But i hope to get into flying planes a little more
Okay - so this is going to make it a little harder as you try to learn to fly a plane while designing and building one. You are probably also facing a deadline given that school will be out soon? For the project is it a must have that you fly the plane yourself or can you find a friend with plane skills to fly your design for you?
 

Dreamy_Bongo

...Because I was inverted
#11
I think "own" design can be interpreted as getting inspiration from another plane. For instance, seeing a known working design and guestimating it's measurements and assembly should suffice.
 
#12
Ya its kinda tricky because i don't have any freinds that fly rc planes. So my dad is kind of helping me because he has his pilots license so he is helping me kind of with the design a bit
 
#13
Simple, simple, simple. Keep it long, light, and ugly and it'll surely fly great. Do you have any size restrictions? Will it be tested inside or outside? If you have the room, bigger is always better. Your wing loading will be light and gives you plenty of room to move electronics around for balance. Go with something with a simple dihedral. I know it's not very popular, but I've had great luck with v-tails especially on motor-gliders. I believe you're TX shouldn't have any problems with that.
 

clolsonus

Active member
#14
I am just skimming this topic, so sorry if I missed something, but I think in order to get helpful feedback here, you would need to post pictures of your design attempts. There are some basic rules of thumb for RC airplane design in terms of sizing the wing and tail surfaces, length of fuselage, relative placement of wing, recommended power, CG location, etc. If you aren't starting with the basic aircraft feature and dimensions in roughly the right ball park, it can be very challenging to get your design to fly. (Don't expect to be able to whip out crazy designs like the flite test guys until you have a lot of more basic successful designs under your belt.) You can't ignore physics and aerodynamics and hope you'll somehow get lucky.

This might not be exactly how I would tackle the problem, but there is lots of good [basic] information here: https://www.instructables.com/id/Design-Build-Your-Own-Electric-RC-Airplane/

If you haven't done RC before, there are other super basic things that need to be taken care of. I would summarize all of these things by saying craftsmanship is very important. Wings and tail surfaces need to be straight and square without unintended warping or misalignment. Hinges need to be free moving, but also solid and not sloppy. Control linkages also need to move freely and not be sloppy. You want about the same amount of up motion as down motion in the control surface ... maybe about 20-30 degrees up and down is a good start. You shouldn't be able to grab the control surface and slop it around with hinge play or slop from a loose linkage ... it should be pretty tight. It is essential that the CG be in about the right place. There are ways to estimate the location depending on your design. The thrust line on your motor is important. Straight/square is usually ok, but again craftsmanship is important. Down the road you might want a little bit of down/right thrust to help the plane react less to changes in throttle, but I wouldn't worry too much about that at this stage.

For a school project, write about the things you tried and why you tried them, followed by the results or the progression of results. If I was a teacher, I'd love to see your wheels spinning, see your thought process, see your design evolution. It took the Wright brothers years to figure out some basic things. We have a head start, but there is still some complexity and non-obvious things to learn if you haven't seen them before. It is definitely fun and rewarding to figure things out for yourself, so good luck!